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kc3-lang/angle/src/libGLESv2/validationES.cpp

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  • Author : Jamie Madill
    Date : 2014-08-04 10:47:59
    Hash : d9ba4f73
    Message : Move implementation of hasMappedBuffer to State. Refactoring patch only. BUG=angle:571 Change-Id: Ib9f3145eaa457d94e488fd42eb4c4b9133768996 Reviewed-on: https://chromium-review.googlesource.com/210643 Tested-by: Jamie Madill <jmadill@chromium.org> Reviewed-by: Geoff Lang <geofflang@chromium.org> Reviewed-by: Shannon Woods <shannonwoods@chromium.org>

  • src/libGLESv2/validationES.cpp
  • #include "precompiled.h"
    //
    // Copyright (c) 2013-2014 The ANGLE Project Authors. All rights reserved.
    // Use of this source code is governed by a BSD-style license that can be
    // found in the LICENSE file.
    //
    
    // validationES.h: Validation functions for generic OpenGL ES entry point parameters
    
    #include "libGLESv2/validationES.h"
    #include "libGLESv2/validationES2.h"
    #include "libGLESv2/validationES3.h"
    #include "libGLESv2/Context.h"
    #include "libGLESv2/Texture.h"
    #include "libGLESv2/Framebuffer.h"
    #include "libGLESv2/FramebufferAttachment.h"
    #include "libGLESv2/formatutils.h"
    #include "libGLESv2/main.h"
    #include "libGLESv2/Query.h"
    #include "libGLESv2/ProgramBinary.h"
    #include "libGLESv2/TransformFeedback.h"
    #include "libGLESv2/VertexArray.h"
    
    #include "common/mathutil.h"
    #include "common/utilities.h"
    
    namespace gl
    {
    
    bool ValidCap(const Context *context, GLenum cap)
    {
        switch (cap)
        {
          case GL_CULL_FACE:
          case GL_POLYGON_OFFSET_FILL:
          case GL_SAMPLE_ALPHA_TO_COVERAGE:
          case GL_SAMPLE_COVERAGE:
          case GL_SCISSOR_TEST:
          case GL_STENCIL_TEST:
          case GL_DEPTH_TEST:
          case GL_BLEND:
          case GL_DITHER:
            return true;
          case GL_PRIMITIVE_RESTART_FIXED_INDEX:
          case GL_RASTERIZER_DISCARD:
            return (context->getClientVersion() >= 3);
          default:
            return false;
        }
    }
    
    bool ValidTextureTarget(const Context *context, GLenum target)
    {
        switch (target)
        {
          case GL_TEXTURE_2D:
          case GL_TEXTURE_CUBE_MAP:
            return true;
    
          case GL_TEXTURE_3D:
          case GL_TEXTURE_2D_ARRAY:
            return (context->getClientVersion() >= 3);
    
          default:
            return false;
        }
    }
    
    // This function differs from ValidTextureTarget in that the target must be
    // usable as the destination of a 2D operation-- so a cube face is valid, but
    // GL_TEXTURE_CUBE_MAP is not.
    // Note: duplicate of IsInternalTextureTarget
    bool ValidTexture2DDestinationTarget(const Context *context, GLenum target)
    {
        switch (target)
        {
          case GL_TEXTURE_2D:
          case GL_TEXTURE_CUBE_MAP_POSITIVE_X:
          case GL_TEXTURE_CUBE_MAP_NEGATIVE_X:
          case GL_TEXTURE_CUBE_MAP_POSITIVE_Y:
          case GL_TEXTURE_CUBE_MAP_NEGATIVE_Y:
          case GL_TEXTURE_CUBE_MAP_POSITIVE_Z:
          case GL_TEXTURE_CUBE_MAP_NEGATIVE_Z:
            return true;
          case GL_TEXTURE_2D_ARRAY:
          case GL_TEXTURE_3D:
            return (context->getClientVersion() >= 3);
          default:
            return false;
        }
    }
    
    bool ValidFramebufferTarget(GLenum target)
    {
        META_ASSERT(GL_DRAW_FRAMEBUFFER_ANGLE == GL_DRAW_FRAMEBUFFER && GL_READ_FRAMEBUFFER_ANGLE == GL_READ_FRAMEBUFFER);
    
        switch (target)
        {
          case GL_FRAMEBUFFER:      return true;
          case GL_READ_FRAMEBUFFER: return true;
          case GL_DRAW_FRAMEBUFFER: return true;
          default:                  return false;
        }
    }
    
    bool ValidBufferTarget(const Context *context, GLenum target)
    {
        switch (target)
        {
          case GL_ARRAY_BUFFER:
          case GL_ELEMENT_ARRAY_BUFFER:
            return true;
    
          case GL_PIXEL_PACK_BUFFER:
          case GL_PIXEL_UNPACK_BUFFER:
            return context->getExtensions().pixelBufferObject;
    
          case GL_COPY_READ_BUFFER:
          case GL_COPY_WRITE_BUFFER:
          case GL_TRANSFORM_FEEDBACK_BUFFER:
          case GL_UNIFORM_BUFFER:
            return (context->getClientVersion() >= 3);
    
          default:
            return false;
        }
    }
    
    bool ValidBufferParameter(const Context *context, GLenum pname)
    {
        switch (pname)
        {
          case GL_BUFFER_USAGE:
          case GL_BUFFER_SIZE:
            return true;
    
          // GL_BUFFER_MAP_POINTER is a special case, and may only be
          // queried with GetBufferPointerv
          case GL_BUFFER_ACCESS_FLAGS:
          case GL_BUFFER_MAPPED:
          case GL_BUFFER_MAP_OFFSET:
          case GL_BUFFER_MAP_LENGTH:
            return (context->getClientVersion() >= 3);
    
          default:
            return false;
        }
    }
    
    bool ValidMipLevel(const Context *context, GLenum target, GLint level)
    {
        size_t maxDimension = 0;
        switch (target)
        {
          case GL_TEXTURE_2D:                  maxDimension = context->getCaps().max2DTextureSize;       break;
          case GL_TEXTURE_CUBE_MAP:
          case GL_TEXTURE_CUBE_MAP_POSITIVE_X:
          case GL_TEXTURE_CUBE_MAP_NEGATIVE_X:
          case GL_TEXTURE_CUBE_MAP_POSITIVE_Y:
          case GL_TEXTURE_CUBE_MAP_NEGATIVE_Y:
          case GL_TEXTURE_CUBE_MAP_POSITIVE_Z:
          case GL_TEXTURE_CUBE_MAP_NEGATIVE_Z: maxDimension = context->getCaps().maxCubeMapTextureSize;  break;
          case GL_TEXTURE_3D:                  maxDimension = context->getCaps().max3DTextureSize;       break;
          case GL_TEXTURE_2D_ARRAY:            maxDimension = context->getCaps().max2DTextureSize;       break;
          default: UNREACHABLE();
        }
    
        return level <= gl::log2(maxDimension);
    }
    
    bool ValidImageSize(const gl::Context *context, GLenum target, GLint level,
                        GLsizei width, GLsizei height, GLsizei depth)
    {
        if (level < 0 || width < 0 || height < 0 || depth < 0)
        {
            return false;
        }
    
        if (!context->getExtensions().textureNPOT &&
            (level != 0 && (!gl::isPow2(width) || !gl::isPow2(height) || !gl::isPow2(depth))))
        {
            return false;
        }
    
        if (!ValidMipLevel(context, target, level))
        {
            return false;
        }
    
        return true;
    }
    
    bool ValidCompressedImageSize(const gl::Context *context, GLenum internalFormat, GLsizei width, GLsizei height)
    {
        const gl::InternalFormat &formatInfo = gl::GetInternalFormatInfo(internalFormat);
        if (!formatInfo.compressed)
        {
            return false;
        }
    
        if (width  < 0 || (static_cast<GLuint>(width)  > formatInfo.compressedBlockWidth  && width  % formatInfo.compressedBlockWidth != 0) ||
            height < 0 || (static_cast<GLuint>(height) > formatInfo.compressedBlockHeight && height % formatInfo.compressedBlockHeight != 0))
        {
            return false;
        }
    
        return true;
    }
    
    bool ValidQueryType(const Context *context, GLenum queryType)
    {
        META_ASSERT(GL_ANY_SAMPLES_PASSED == GL_ANY_SAMPLES_PASSED_EXT);
        META_ASSERT(GL_ANY_SAMPLES_PASSED_CONSERVATIVE == GL_ANY_SAMPLES_PASSED_CONSERVATIVE_EXT);
    
        switch (queryType)
        {
          case GL_ANY_SAMPLES_PASSED:
          case GL_ANY_SAMPLES_PASSED_CONSERVATIVE:
            return true;
          case GL_TRANSFORM_FEEDBACK_PRIMITIVES_WRITTEN:
            return (context->getClientVersion() >= 3);
          default:
            return false;
        }
    }
    
    bool ValidProgram(const Context *context, GLuint id)
    {
        // ES3 spec (section 2.11.1) -- "Commands that accept shader or program object names will generate the
        // error INVALID_VALUE if the provided name is not the name of either a shader or program object and
        // INVALID_OPERATION if the provided name identifies an object that is not the expected type."
    
        if (context->getProgram(id) != NULL)
        {
            return true;
        }
        else if (context->getShader(id) != NULL)
        {
            // ID is the wrong type
            return gl::error(GL_INVALID_OPERATION, false);
        }
        else
        {
            // No shader/program object has this ID
            return gl::error(GL_INVALID_VALUE, false);
        }
    }
    
    bool ValidateAttachmentTarget(const gl::Context *context, GLenum attachment)
    {
        if (attachment >= GL_COLOR_ATTACHMENT0_EXT && attachment <= GL_COLOR_ATTACHMENT15_EXT)
        {
            const unsigned int colorAttachment = (attachment - GL_COLOR_ATTACHMENT0_EXT);
    
            if (colorAttachment >= context->getCaps().maxColorAttachments)
            {
                return gl::error(GL_INVALID_VALUE, false);
            }
        }
        else
        {
            switch (attachment)
            {
              case GL_DEPTH_ATTACHMENT:
              case GL_STENCIL_ATTACHMENT:
                break;
    
              case GL_DEPTH_STENCIL_ATTACHMENT:
                if (context->getClientVersion() < 3)
                {
                    return gl::error(GL_INVALID_ENUM, false);
                }
                break;
    
              default:
                return gl::error(GL_INVALID_ENUM, false);
            }
        }
    
        return true;
    }
    
    bool ValidateRenderbufferStorageParameters(const gl::Context *context, GLenum target, GLsizei samples,
                                               GLenum internalformat, GLsizei width, GLsizei height,
                                               bool angleExtension)
    {
        switch (target)
        {
          case GL_RENDERBUFFER:
            break;
          default:
            return gl::error(GL_INVALID_ENUM, false);
        }
    
        if (width < 0 || height < 0 || samples < 0)
        {
            return gl::error(GL_INVALID_VALUE, false);
        }
    
        const gl::InternalFormat &formatInfo = gl::GetInternalFormatInfo(internalformat);
        if (!formatInfo.textureSupport(context->getClientVersion(), context->getExtensions()))
        {
            return gl::error(GL_INVALID_ENUM, false);
        }
    
        // ANGLE_framebuffer_multisample does not explicitly state that the internal format must be
        // sized but it does state that the format must be in the ES2.0 spec table 4.5 which contains
        // only sized internal formats. The ES3 spec (section 4.4.2) does, however, state that the
        // internal format must be sized and not an integer format if samples is greater than zero.
        if (formatInfo.pixelBytes == 0)
        {
            return gl::error(GL_INVALID_ENUM, false);
        }
    
        if ((formatInfo.componentType == GL_UNSIGNED_INT || formatInfo.componentType == GL_INT) && samples > 0)
        {
            return gl::error(GL_INVALID_OPERATION, false);
        }
    
        const TextureCaps &formatCaps = context->getTextureCaps().get(internalformat);
        if (!formatCaps.renderable)
        {
            return gl::error(GL_INVALID_ENUM, false);
        }
    
        if (static_cast<GLuint>(std::max(width, height)) > context->getCaps().maxRenderbufferSize)
        {
            return gl::error(GL_INVALID_VALUE, false);
        }
    
        // ANGLE_framebuffer_multisample states that the value of samples must be less than or equal
        // to MAX_SAMPLES_ANGLE (Context::getMaxSupportedSamples) while the ES3.0 spec (section 4.4.2)
        // states that samples must be less than or equal to the maximum samples for the specified
        // internal format.
        if (angleExtension)
        {
            ASSERT(context->getExtensions().framebufferMultisample);
            if (static_cast<GLuint>(samples) > context->getExtensions().maxSamples)
            {
                return gl::error(GL_INVALID_VALUE, false);
            }
    
            // Check if this specific format supports enough samples
            if (static_cast<GLuint>(samples) > formatCaps.getMaxSamples())
            {
                return gl::error(GL_OUT_OF_MEMORY, false);
            }
        }
        else
        {
            if (static_cast<GLuint>(samples) > formatCaps.getMaxSamples())
            {
                return gl::error(GL_INVALID_VALUE, false);
            }
        }
    
        GLuint handle = context->getState().getRenderbufferId();
        if (handle == 0)
        {
            return gl::error(GL_INVALID_OPERATION, false);
        }
    
        return true;
    }
    
    bool ValidateFramebufferRenderbufferParameters(gl::Context *context, GLenum target, GLenum attachment,
                                                   GLenum renderbuffertarget, GLuint renderbuffer)
    {
        if (!ValidFramebufferTarget(target))
        {
            return gl::error(GL_INVALID_ENUM, false);
        }
    
        gl::Framebuffer *framebuffer = context->getState().getTargetFramebuffer(target);
        GLuint framebufferHandle = context->getState().getTargetFramebuffer(target)->id();
    
        if (!framebuffer || (framebufferHandle == 0 && renderbuffer != 0))
        {
            return gl::error(GL_INVALID_OPERATION, false);
        }
    
        if (!ValidateAttachmentTarget(context, attachment))
        {
            return false;
        }
    
        // [OpenGL ES 2.0.25] Section 4.4.3 page 112
        // [OpenGL ES 3.0.2] Section 4.4.2 page 201
        // 'renderbuffer' must be either zero or the name of an existing renderbuffer object of
        // type 'renderbuffertarget', otherwise an INVALID_OPERATION error is generated.
        if (renderbuffer != 0)
        {
            if (!context->getRenderbuffer(renderbuffer))
            {
                return gl::error(GL_INVALID_OPERATION, false);
            }
        }
    
        return true;
    }
    
    static bool IsPartialBlit(gl::Context *context, gl::FramebufferAttachment *readBuffer, gl::FramebufferAttachment *writeBuffer,
                              GLint srcX0, GLint srcY0, GLint srcX1, GLint srcY1,
                              GLint dstX0, GLint dstY0, GLint dstX1, GLint dstY1)
    {
        if (srcX0 != 0 || srcY0 != 0 || dstX0 != 0 || dstY0 != 0 ||
            dstX1 != writeBuffer->getWidth() || dstY1 != writeBuffer->getHeight() ||
            srcX1 != readBuffer->getWidth() || srcY1 != readBuffer->getHeight())
        {
            return true;
        }
        else if (context->getState().isScissorTestEnabled())
        {
            const Rectangle &scissor = context->getState().getScissor();
    
            return scissor.x > 0 || scissor.y > 0 ||
                   scissor.width < writeBuffer->getWidth() ||
                   scissor.height < writeBuffer->getHeight();
        }
        else
        {
            return false;
        }
    }
    
    bool ValidateBlitFramebufferParameters(gl::Context *context, GLint srcX0, GLint srcY0, GLint srcX1, GLint srcY1,
                                           GLint dstX0, GLint dstY0, GLint dstX1, GLint dstY1, GLbitfield mask,
                                           GLenum filter, bool fromAngleExtension)
    {
        switch (filter)
        {
          case GL_NEAREST:
            break;
          case GL_LINEAR:
            if (fromAngleExtension)
            {
                return gl::error(GL_INVALID_ENUM, false);
            }
            break;
          default:
            return gl::error(GL_INVALID_ENUM, false);
        }
    
        if ((mask & ~(GL_COLOR_BUFFER_BIT | GL_STENCIL_BUFFER_BIT | GL_DEPTH_BUFFER_BIT)) != 0)
        {
            return gl::error(GL_INVALID_VALUE, false);
        }
    
        if (mask == 0)
        {
            // ES3.0 spec, section 4.3.2 specifies that a mask of zero is valid and no
            // buffers are copied.
            return false;
        }
    
        if (fromAngleExtension && (srcX1 - srcX0 != dstX1 - dstX0 || srcY1 - srcY0 != dstY1 - dstY0))
        {
            ERR("Scaling and flipping in BlitFramebufferANGLE not supported by this implementation.");
            return gl::error(GL_INVALID_OPERATION, false);
        }
    
        // ES3.0 spec, section 4.3.2 states that linear filtering is only available for the
        // color buffer, leaving only nearest being unfiltered from above
        if ((mask & ~GL_COLOR_BUFFER_BIT) != 0 && filter != GL_NEAREST)
        {
            return gl::error(GL_INVALID_OPERATION, false);
        }
    
        if (context->getState().getReadFramebuffer()->id() == context->getState().getDrawFramebuffer()->id())
        {
            if (fromAngleExtension)
            {
                ERR("Blits with the same source and destination framebuffer are not supported by this "
                    "implementation.");
            }
            return gl::error(GL_INVALID_OPERATION, false);
        }
    
        gl::Framebuffer *readFramebuffer = context->getState().getReadFramebuffer();
        gl::Framebuffer *drawFramebuffer = context->getState().getDrawFramebuffer();
        if (!readFramebuffer || readFramebuffer->completeness() != GL_FRAMEBUFFER_COMPLETE ||
            !drawFramebuffer || drawFramebuffer->completeness() != GL_FRAMEBUFFER_COMPLETE)
        {
            return gl::error(GL_INVALID_FRAMEBUFFER_OPERATION, false);
        }
    
        if (drawFramebuffer->getSamples() != 0)
        {
            return gl::error(GL_INVALID_OPERATION, false);
        }
    
        bool sameBounds = srcX0 == dstX0 && srcY0 == dstY0 && srcX1 == dstX1 && srcY1 == dstY1;
    
        if (mask & GL_COLOR_BUFFER_BIT)
        {
            gl::FramebufferAttachment *readColorBuffer = readFramebuffer->getReadColorbuffer();
            gl::FramebufferAttachment *drawColorBuffer = drawFramebuffer->getFirstColorbuffer();
    
            if (readColorBuffer && drawColorBuffer)
            {
                GLenum readInternalFormat = readColorBuffer->getActualFormat();
                const InternalFormat &readFormatInfo = GetInternalFormatInfo(readInternalFormat);
    
                for (unsigned int i = 0; i < gl::IMPLEMENTATION_MAX_DRAW_BUFFERS; i++)
                {
                    if (drawFramebuffer->isEnabledColorAttachment(i))
                    {
                        GLenum drawInternalFormat = drawFramebuffer->getColorbuffer(i)->getActualFormat();
                        const InternalFormat &drawFormatInfo = GetInternalFormatInfo(drawInternalFormat);
    
                        // The GL ES 3.0.2 spec (pg 193) states that:
                        // 1) If the read buffer is fixed point format, the draw buffer must be as well
                        // 2) If the read buffer is an unsigned integer format, the draw buffer must be as well
                        // 3) If the read buffer is a signed integer format, the draw buffer must be as well
                        if ( (readFormatInfo.componentType == GL_UNSIGNED_NORMALIZED || readFormatInfo.componentType == GL_SIGNED_NORMALIZED) &&
                            !(drawFormatInfo.componentType == GL_UNSIGNED_NORMALIZED || drawFormatInfo.componentType == GL_SIGNED_NORMALIZED))
                        {
                            return gl::error(GL_INVALID_OPERATION, false);
                        }
    
                        if (readFormatInfo.componentType == GL_UNSIGNED_INT && drawFormatInfo.componentType != GL_UNSIGNED_INT)
                        {
                            return gl::error(GL_INVALID_OPERATION, false);
                        }
    
                        if (readFormatInfo.componentType == GL_INT && drawFormatInfo.componentType != GL_INT)
                        {
                            return gl::error(GL_INVALID_OPERATION, false);
                        }
    
                        if (readColorBuffer->getSamples() > 0 && (readInternalFormat != drawInternalFormat || !sameBounds))
                        {
                            return gl::error(GL_INVALID_OPERATION, false);
                        }
                    }
                }
    
                if ((readFormatInfo.componentType == GL_INT || readFormatInfo.componentType == GL_UNSIGNED_INT) && filter == GL_LINEAR)
                {
                    return gl::error(GL_INVALID_OPERATION, false);
                }
    
                if (fromAngleExtension)
                {
                    const GLenum readColorbufferType = readFramebuffer->getReadColorbufferType();
                    if (readColorbufferType != GL_TEXTURE_2D && readColorbufferType != GL_RENDERBUFFER)
                    {
                        return gl::error(GL_INVALID_OPERATION, false);
                    }
    
                    for (unsigned int colorAttachment = 0; colorAttachment < gl::IMPLEMENTATION_MAX_DRAW_BUFFERS; colorAttachment++)
                    {
                        if (drawFramebuffer->isEnabledColorAttachment(colorAttachment))
                        {
                            FramebufferAttachment *attachment = drawFramebuffer->getColorbuffer(colorAttachment);
                            ASSERT(attachment);
    
                            if (attachment->type() != GL_TEXTURE_2D && attachment->type() != GL_RENDERBUFFER)
                            {
                                return gl::error(GL_INVALID_OPERATION, false);
                            }
    
                            if (attachment->getActualFormat() != readColorBuffer->getActualFormat())
                            {
                                return gl::error(GL_INVALID_OPERATION, false);
                            }
                        }
                    }
                    if (readFramebuffer->getSamples() != 0 && IsPartialBlit(context, readColorBuffer, drawColorBuffer,
                                                                            srcX0, srcY0, srcX1, srcY1,
                                                                            dstX0, dstY0, dstX1, dstY1))
                    {
                        return gl::error(GL_INVALID_OPERATION, false);
                    }
                }
            }
        }
    
        if (mask & GL_DEPTH_BUFFER_BIT)
        {
            gl::FramebufferAttachment *readDepthBuffer = readFramebuffer->getDepthbuffer();
            gl::FramebufferAttachment *drawDepthBuffer = drawFramebuffer->getDepthbuffer();
    
            if (readDepthBuffer && drawDepthBuffer)
            {
                if (readDepthBuffer->getActualFormat() != drawDepthBuffer->getActualFormat())
                {
                    return gl::error(GL_INVALID_OPERATION, false);
                }
    
                if (readDepthBuffer->getSamples() > 0 && !sameBounds)
                {
                    return gl::error(GL_INVALID_OPERATION, false);
                }
    
                if (fromAngleExtension)
                {
                    if (IsPartialBlit(context, readDepthBuffer, drawDepthBuffer,
                                      srcX0, srcY0, srcX1, srcY1, dstX0, dstY0, dstX1, dstY1))
                    {
                        ERR("Only whole-buffer depth and stencil blits are supported by this implementation.");
                        return gl::error(GL_INVALID_OPERATION, false); // only whole-buffer copies are permitted
                    }
    
                    if (readDepthBuffer->getSamples() != 0 || drawDepthBuffer->getSamples() != 0)
                    {
                        return gl::error(GL_INVALID_OPERATION, false);
                    }
                }
            }
        }
    
        if (mask & GL_STENCIL_BUFFER_BIT)
        {
            gl::FramebufferAttachment *readStencilBuffer = readFramebuffer->getStencilbuffer();
            gl::FramebufferAttachment *drawStencilBuffer = drawFramebuffer->getStencilbuffer();
    
            if (readStencilBuffer && drawStencilBuffer)
            {
                if (readStencilBuffer->getActualFormat() != drawStencilBuffer->getActualFormat())
                {
                    return gl::error(GL_INVALID_OPERATION, false);
                }
    
                if (readStencilBuffer->getSamples() > 0 && !sameBounds)
                {
                    return gl::error(GL_INVALID_OPERATION, false);
                }
    
                if (fromAngleExtension)
                {
                    if (IsPartialBlit(context, readStencilBuffer, drawStencilBuffer,
                                      srcX0, srcY0, srcX1, srcY1, dstX0, dstY0, dstX1, dstY1))
                    {
                        ERR("Only whole-buffer depth and stencil blits are supported by this implementation.");
                        return gl::error(GL_INVALID_OPERATION, false); // only whole-buffer copies are permitted
                    }
    
                    if (readStencilBuffer->getSamples() != 0 || drawStencilBuffer->getSamples() != 0)
                    {
                        return gl::error(GL_INVALID_OPERATION, false);
                    }
                }
            }
        }
    
        return true;
    }
    
    bool ValidateGetVertexAttribParameters(GLenum pname, int clientVersion)
    {
        switch (pname)
        {
          case GL_VERTEX_ATTRIB_ARRAY_ENABLED:
          case GL_VERTEX_ATTRIB_ARRAY_SIZE:
          case GL_VERTEX_ATTRIB_ARRAY_STRIDE:
          case GL_VERTEX_ATTRIB_ARRAY_TYPE:
          case GL_VERTEX_ATTRIB_ARRAY_NORMALIZED:
          case GL_VERTEX_ATTRIB_ARRAY_BUFFER_BINDING:
          case GL_CURRENT_VERTEX_ATTRIB:
            return true;
    
          case GL_VERTEX_ATTRIB_ARRAY_DIVISOR:
            // Don't verify ES3 context because GL_VERTEX_ATTRIB_ARRAY_DIVISOR_ANGLE uses
            // the same constant.
            META_ASSERT(GL_VERTEX_ATTRIB_ARRAY_DIVISOR == GL_VERTEX_ATTRIB_ARRAY_DIVISOR_ANGLE);
            return true;
    
          case GL_VERTEX_ATTRIB_ARRAY_INTEGER:
            return ((clientVersion >= 3) ? true : gl::error(GL_INVALID_ENUM, false));
    
          default:
            return gl::error(GL_INVALID_ENUM, false);
        }
    }
    
    bool ValidateTexParamParameters(gl::Context *context, GLenum pname, GLint param)
    {
        switch (pname)
        {
          case GL_TEXTURE_WRAP_R:
          case GL_TEXTURE_SWIZZLE_R:
          case GL_TEXTURE_SWIZZLE_G:
          case GL_TEXTURE_SWIZZLE_B:
          case GL_TEXTURE_SWIZZLE_A:
          case GL_TEXTURE_BASE_LEVEL:
          case GL_TEXTURE_MAX_LEVEL:
          case GL_TEXTURE_COMPARE_MODE:
          case GL_TEXTURE_COMPARE_FUNC:
          case GL_TEXTURE_MIN_LOD:
          case GL_TEXTURE_MAX_LOD:
            if (context->getClientVersion() < 3)
            {
                return gl::error(GL_INVALID_ENUM, false);
            }
            break;
    
          default: break;
        }
    
        switch (pname)
        {
          case GL_TEXTURE_WRAP_S:
          case GL_TEXTURE_WRAP_T:
          case GL_TEXTURE_WRAP_R:
            switch (param)
            {
              case GL_REPEAT:
              case GL_CLAMP_TO_EDGE:
              case GL_MIRRORED_REPEAT:
                return true;
              default:
                return gl::error(GL_INVALID_ENUM, false);
            }
    
          case GL_TEXTURE_MIN_FILTER:
            switch (param)
            {
              case GL_NEAREST:
              case GL_LINEAR:
              case GL_NEAREST_MIPMAP_NEAREST:
              case GL_LINEAR_MIPMAP_NEAREST:
              case GL_NEAREST_MIPMAP_LINEAR:
              case GL_LINEAR_MIPMAP_LINEAR:
                return true;
              default:
                return gl::error(GL_INVALID_ENUM, false);
            }
            break;
    
          case GL_TEXTURE_MAG_FILTER:
            switch (param)
            {
              case GL_NEAREST:
              case GL_LINEAR:
                return true;
              default:
                return gl::error(GL_INVALID_ENUM, false);
            }
            break;
    
          case GL_TEXTURE_USAGE_ANGLE:
            switch (param)
            {
              case GL_NONE:
              case GL_FRAMEBUFFER_ATTACHMENT_ANGLE:
                return true;
              default:
                return gl::error(GL_INVALID_ENUM, false);
            }
            break;
    
          case GL_TEXTURE_MAX_ANISOTROPY_EXT:
            if (!context->getExtensions().textureFilterAnisotropic)
            {
                return gl::error(GL_INVALID_ENUM, false);
            }
    
            // we assume the parameter passed to this validation method is truncated, not rounded
            if (param < 1)
            {
                return gl::error(GL_INVALID_VALUE, false);
            }
            return true;
    
          case GL_TEXTURE_MIN_LOD:
          case GL_TEXTURE_MAX_LOD:
            // any value is permissible
            return true;
    
          case GL_TEXTURE_COMPARE_MODE:
            // Acceptable mode parameters from GLES 3.0.2 spec, table 3.17
            switch (param)
            {
              case GL_NONE:
              case GL_COMPARE_REF_TO_TEXTURE:
                return true;
              default:
                return gl::error(GL_INVALID_ENUM, false);
            }
            break;
    
          case GL_TEXTURE_COMPARE_FUNC:
            // Acceptable function parameters from GLES 3.0.2 spec, table 3.17
            switch (param)
            {
              case GL_LEQUAL:
              case GL_GEQUAL:
              case GL_LESS:
              case GL_GREATER:
              case GL_EQUAL:
              case GL_NOTEQUAL:
              case GL_ALWAYS:
              case GL_NEVER:
                return true;
              default:
                return gl::error(GL_INVALID_ENUM, false);
            }
            break;
    
          case GL_TEXTURE_SWIZZLE_R:
          case GL_TEXTURE_SWIZZLE_G:
          case GL_TEXTURE_SWIZZLE_B:
          case GL_TEXTURE_SWIZZLE_A:
            switch (param)
            {
              case GL_RED:
              case GL_GREEN:
              case GL_BLUE:
              case GL_ALPHA:
              case GL_ZERO:
              case GL_ONE:
                return true;
              default:
                return gl::error(GL_INVALID_ENUM, false);
            }
            break;
    
          case GL_TEXTURE_BASE_LEVEL:
          case GL_TEXTURE_MAX_LEVEL:
            if (param < 0)
            {
                return gl::error(GL_INVALID_VALUE, false);
            }
            return true;
    
          default:
            return gl::error(GL_INVALID_ENUM, false);
        }
    }
    
    bool ValidateSamplerObjectParameter(GLenum pname)
    {
        switch (pname)
        {
          case GL_TEXTURE_MIN_FILTER:
          case GL_TEXTURE_MAG_FILTER:
          case GL_TEXTURE_WRAP_S:
          case GL_TEXTURE_WRAP_T:
          case GL_TEXTURE_WRAP_R:
          case GL_TEXTURE_MIN_LOD:
          case GL_TEXTURE_MAX_LOD:
          case GL_TEXTURE_COMPARE_MODE:
          case GL_TEXTURE_COMPARE_FUNC:
            return true;
    
          default:
            return gl::error(GL_INVALID_ENUM, false);
        }
    }
    
    bool ValidateReadPixelsParameters(gl::Context *context, GLint x, GLint y, GLsizei width, GLsizei height,
                                      GLenum format, GLenum type, GLsizei *bufSize, GLvoid *pixels)
    {
        gl::Framebuffer *framebuffer = context->getState().getReadFramebuffer();
        ASSERT(framebuffer);
    
        if (framebuffer->completeness() != GL_FRAMEBUFFER_COMPLETE)
        {
            return gl::error(GL_INVALID_FRAMEBUFFER_OPERATION, false);
        }
    
        if (context->getState().getReadFramebuffer()->id() != 0 && framebuffer->getSamples() != 0)
        {
            return gl::error(GL_INVALID_OPERATION, false);
        }
    
        if (!framebuffer->getReadColorbuffer())
        {
            return gl::error(GL_INVALID_OPERATION, false);
        }
    
        GLenum currentInternalFormat, currentFormat, currentType;
        GLuint clientVersion = context->getClientVersion();
    
        context->getCurrentReadFormatType(&currentInternalFormat, &currentFormat, &currentType);
    
        bool validReadFormat = (clientVersion < 3) ? ValidES2ReadFormatType(context, format, type) :
                                                     ValidES3ReadFormatType(context, currentInternalFormat, format, type);
    
        if (!(currentFormat == format && currentType == type) && !validReadFormat)
        {
            return gl::error(GL_INVALID_OPERATION, false);
        }
    
        GLenum sizedInternalFormat = GetSizedInternalFormat(format, type);
        const InternalFormat &sizedFormatInfo = GetInternalFormatInfo(sizedInternalFormat);
    
        GLsizei outputPitch = sizedFormatInfo.computeRowPitch(type, width, context->getState().getPackAlignment());
        // sized query sanity check
        if (bufSize)
        {
            int requiredSize = outputPitch * height;
            if (requiredSize > *bufSize)
            {
                return gl::error(GL_INVALID_OPERATION, false);
            }
        }
    
        return true;
    }
    
    bool ValidateBeginQuery(gl::Context *context, GLenum target, GLuint id)
    {
        if (!ValidQueryType(context, target))
        {
            return gl::error(GL_INVALID_ENUM, false);
        }
    
        if (id == 0)
        {
            return gl::error(GL_INVALID_OPERATION, false);
        }
    
        // From EXT_occlusion_query_boolean: If BeginQueryEXT is called with an <id>
        // of zero, if the active query object name for <target> is non-zero (for the
        // targets ANY_SAMPLES_PASSED_EXT and ANY_SAMPLES_PASSED_CONSERVATIVE_EXT, if
        // the active query for either target is non-zero), if <id> is the name of an
        // existing query object whose type does not match <target>, or if <id> is the
        // active query object name for any query type, the error INVALID_OPERATION is
        // generated.
    
        // Ensure no other queries are active
        // NOTE: If other queries than occlusion are supported, we will need to check
        // separately that:
        //    a) The query ID passed is not the current active query for any target/type
        //    b) There are no active queries for the requested target (and in the case
        //       of GL_ANY_SAMPLES_PASSED_EXT and GL_ANY_SAMPLES_PASSED_CONSERVATIVE_EXT,
        //       no query may be active for either if glBeginQuery targets either.
        if (context->getState().isQueryActive())
        {
            return gl::error(GL_INVALID_OPERATION, false);
        }
    
        Query *queryObject = context->getQuery(id, true, target);
    
        // check that name was obtained with glGenQueries
        if (!queryObject)
        {
            return gl::error(GL_INVALID_OPERATION, false);
        }
    
        // check for type mismatch
        if (queryObject->getType() != target)
        {
            return gl::error(GL_INVALID_OPERATION, false);
        }
    
        return true;
    }
    
    bool ValidateEndQuery(gl::Context *context, GLenum target)
    {
        if (!ValidQueryType(context, target))
        {
            return gl::error(GL_INVALID_ENUM, false);
        }
    
        const Query *queryObject = context->getState().getActiveQuery(target);
    
        if (queryObject == NULL)
        {
            return gl::error(GL_INVALID_OPERATION, false);
        }
    
        if (!queryObject->isStarted())
        {
            return gl::error(GL_INVALID_OPERATION, false);
        }
    
        return true;
    }
    
    static bool ValidateUniformCommonBase(gl::Context *context, GLenum targetUniformType,
                                          GLint location, GLsizei count, LinkedUniform **uniformOut)
    {
        if (count < 0)
        {
            return gl::error(GL_INVALID_VALUE, false);
        }
    
        gl::ProgramBinary *programBinary = context->getState().getCurrentProgramBinary();
        if (!programBinary)
        {
            return gl::error(GL_INVALID_OPERATION, false);
        }
    
        if (location == -1)
        {
            // Silently ignore the uniform command
            return false;
        }
    
        if (!programBinary->isValidUniformLocation(location))
        {
            return gl::error(GL_INVALID_OPERATION, false);
        }
    
        LinkedUniform *uniform = programBinary->getUniformByLocation(location);
    
        // attempting to write an array to a non-array uniform is an INVALID_OPERATION
        if (uniform->elementCount() == 1 && count > 1)
        {
            return gl::error(GL_INVALID_OPERATION, false);
        }
    
        *uniformOut = uniform;
        return true;
    }
    
    bool ValidateUniform(gl::Context *context, GLenum uniformType, GLint location, GLsizei count)
    {
        // Check for ES3 uniform entry points
        if (VariableComponentType(uniformType) == GL_UNSIGNED_INT && context->getClientVersion() < 3)
        {
            return gl::error(GL_INVALID_OPERATION, false);
        }
    
        LinkedUniform *uniform = NULL;
        if (!ValidateUniformCommonBase(context, uniformType, location, count, &uniform))
        {
            return false;
        }
    
        GLenum targetBoolType = VariableBoolVectorType(uniformType);
        bool samplerUniformCheck = (IsSampler(uniform->type) && uniformType == GL_INT);
        if (!samplerUniformCheck && uniformType != uniform->type && targetBoolType != uniform->type)
        {
            return gl::error(GL_INVALID_OPERATION, false);
        }
    
        return true;
    }
    
    bool ValidateUniformMatrix(gl::Context *context, GLenum matrixType, GLint location, GLsizei count,
                               GLboolean transpose)
    {
        // Check for ES3 uniform entry points
        int rows = VariableRowCount(matrixType);
        int cols = VariableColumnCount(matrixType);
        if (rows != cols && context->getClientVersion() < 3)
        {
            return gl::error(GL_INVALID_OPERATION, false);
        }
    
        if (transpose != GL_FALSE && context->getClientVersion() < 3)
        {
            return gl::error(GL_INVALID_VALUE, false);
        }
    
        LinkedUniform *uniform = NULL;
        if (!ValidateUniformCommonBase(context, matrixType, location, count, &uniform))
        {
            return false;
        }
    
        if (uniform->type != matrixType)
        {
            return gl::error(GL_INVALID_OPERATION, false);
        }
    
        return true;
    }
    
    bool ValidateStateQuery(gl::Context *context, GLenum pname, GLenum *nativeType, unsigned int *numParams)
    {
        if (!context->getQueryParameterInfo(pname, nativeType, numParams))
        {
            return gl::error(GL_INVALID_ENUM, false);
        }
    
        if (pname >= GL_DRAW_BUFFER0 && pname <= GL_DRAW_BUFFER15)
        {
            unsigned int colorAttachment = (pname - GL_DRAW_BUFFER0);
    
            if (colorAttachment >= context->getCaps().maxDrawBuffers)
            {
                return gl::error(GL_INVALID_OPERATION, false);
            }
        }
    
        switch (pname)
        {
          case GL_TEXTURE_BINDING_2D:
          case GL_TEXTURE_BINDING_CUBE_MAP:
          case GL_TEXTURE_BINDING_3D:
          case GL_TEXTURE_BINDING_2D_ARRAY:
            if (context->getState().getActiveSampler() >= context->getMaximumCombinedTextureImageUnits())
            {
                return gl::error(GL_INVALID_OPERATION, false);
            }
            break;
    
          case GL_IMPLEMENTATION_COLOR_READ_TYPE:
          case GL_IMPLEMENTATION_COLOR_READ_FORMAT:
            {
                Framebuffer *framebuffer = context->getState().getReadFramebuffer();
                ASSERT(framebuffer);
                if (framebuffer->completeness() != GL_FRAMEBUFFER_COMPLETE)
                {
                    return gl::error(GL_INVALID_OPERATION, false);
                }
    
                FramebufferAttachment *attachment = framebuffer->getReadColorbuffer();
                if (!attachment)
                {
                    return gl::error(GL_INVALID_OPERATION, false);
                }
            }
            break;
    
          default:
            break;
        }
    
        // pname is valid, but there are no parameters to return
        if (numParams == 0)
        {
            return false;
        }
    
        return true;
    }
    
    bool ValidateCopyTexImageParametersBase(gl::Context* context, GLenum target, GLint level, GLenum internalformat, bool isSubImage,
                                            GLint xoffset, GLint yoffset, GLint zoffset, GLint x, GLint y, GLsizei width, GLsizei height,
                                            GLint border, GLenum *textureFormatOut)
    {
    
        if (!ValidTexture2DDestinationTarget(context, target))
        {
            return gl::error(GL_INVALID_ENUM, false);
        }
    
        if (level < 0 || xoffset < 0 || yoffset < 0 || zoffset < 0 || width < 0 || height < 0)
        {
            return gl::error(GL_INVALID_VALUE, false);
        }
    
        if (std::numeric_limits<GLsizei>::max() - xoffset < width || std::numeric_limits<GLsizei>::max() - yoffset < height)
        {
            return gl::error(GL_INVALID_VALUE, false);
        }
    
        if (border != 0)
        {
            return gl::error(GL_INVALID_VALUE, false);
        }
    
        if (!ValidMipLevel(context, target, level))
        {
            return gl::error(GL_INVALID_VALUE, false);
        }
    
        gl::Framebuffer *framebuffer = context->getState().getReadFramebuffer();
        if (framebuffer->completeness() != GL_FRAMEBUFFER_COMPLETE)
        {
            return gl::error(GL_INVALID_FRAMEBUFFER_OPERATION, false);
        }
    
        if (context->getState().getReadFramebuffer()->id() != 0 && framebuffer->getSamples() != 0)
        {
            return gl::error(GL_INVALID_OPERATION, false);
        }
    
        const gl::Caps &caps = context->getCaps();
    
        gl::Texture *texture = NULL;
        GLenum textureInternalFormat = GL_NONE;
        GLint textureLevelWidth = 0;
        GLint textureLevelHeight = 0;
        GLint textureLevelDepth = 0;
        GLuint maxDimension = 0;
    
        switch (target)
        {
          case GL_TEXTURE_2D:
            {
                gl::Texture2D *texture2d = context->getTexture2D();
                if (texture2d)
                {
                    textureInternalFormat = texture2d->getInternalFormat(level);
                    textureLevelWidth = texture2d->getWidth(level);
                    textureLevelHeight = texture2d->getHeight(level);
                    textureLevelDepth = 1;
                    texture = texture2d;
                    maxDimension = caps.max2DTextureSize;
                }
            }
            break;
    
          case GL_TEXTURE_CUBE_MAP_POSITIVE_X:
          case GL_TEXTURE_CUBE_MAP_NEGATIVE_X:
          case GL_TEXTURE_CUBE_MAP_POSITIVE_Y:
          case GL_TEXTURE_CUBE_MAP_NEGATIVE_Y:
          case GL_TEXTURE_CUBE_MAP_POSITIVE_Z:
          case GL_TEXTURE_CUBE_MAP_NEGATIVE_Z:
            {
                gl::TextureCubeMap *textureCube = context->getTextureCubeMap();
                if (textureCube)
                {
                    textureInternalFormat = textureCube->getInternalFormat(target, level);
                    textureLevelWidth = textureCube->getWidth(target, level);
                    textureLevelHeight = textureCube->getHeight(target, level);
                    textureLevelDepth = 1;
                    texture = textureCube;
                    maxDimension = caps.maxCubeMapTextureSize;
                }
            }
            break;
    
          case GL_TEXTURE_2D_ARRAY:
            {
                gl::Texture2DArray *texture2dArray = context->getTexture2DArray();
                if (texture2dArray)
                {
                    textureInternalFormat = texture2dArray->getInternalFormat(level);
                    textureLevelWidth = texture2dArray->getWidth(level);
                    textureLevelHeight = texture2dArray->getHeight(level);
                    textureLevelDepth = texture2dArray->getLayers(level);
                    texture = texture2dArray;
                    maxDimension = caps.max2DTextureSize;
                }
            }
            break;
    
          case GL_TEXTURE_3D:
            {
                gl::Texture3D *texture3d = context->getTexture3D();
                if (texture3d)
                {
                    textureInternalFormat = texture3d->getInternalFormat(level);
                    textureLevelWidth = texture3d->getWidth(level);
                    textureLevelHeight = texture3d->getHeight(level);
                    textureLevelDepth = texture3d->getDepth(level);
                    texture = texture3d;
                    maxDimension = caps.max3DTextureSize;
                }
            }
            break;
    
          default:
            return gl::error(GL_INVALID_ENUM, false);
        }
    
        if (!texture)
        {
            return gl::error(GL_INVALID_OPERATION, false);
        }
    
        if (texture->isImmutable() && !isSubImage)
        {
            return gl::error(GL_INVALID_OPERATION, false);
        }
    
        const gl::InternalFormat &formatInfo = gl::GetInternalFormatInfo(internalformat);
    
        if (formatInfo.depthBits > 0)
        {
            return gl::error(GL_INVALID_OPERATION, false);
        }
    
        if (formatInfo.compressed)
        {
            if (((width % formatInfo.compressedBlockWidth) != 0 && width != textureLevelWidth) ||
                ((height % formatInfo.compressedBlockHeight) != 0 && height != textureLevelHeight))
            {
                return gl::error(GL_INVALID_OPERATION, false);
            }
        }
    
        if (isSubImage)
        {
            if (xoffset + width > textureLevelWidth ||
                yoffset + height > textureLevelHeight ||
                zoffset >= textureLevelDepth)
            {
                return gl::error(GL_INVALID_VALUE, false);
            }
        }
        else
        {
            if (IsCubemapTextureTarget(target) && width != height)
            {
                return gl::error(GL_INVALID_VALUE, false);
            }
    
            if (!formatInfo.textureSupport(context->getClientVersion(), context->getExtensions()))
            {
                return gl::error(GL_INVALID_ENUM, false);
            }
    
            int maxLevelDimension = (maxDimension >> level);
            if (static_cast<int>(width) > maxLevelDimension || static_cast<int>(height) > maxLevelDimension)
            {
                return gl::error(GL_INVALID_VALUE, false);
            }
        }
    
        *textureFormatOut = textureInternalFormat;
        return true;
    }
    
    static bool ValidateDrawBase(const gl::State &state, GLenum mode, GLsizei count)
    {
        switch (mode)
        {
          case GL_POINTS:
          case GL_LINES:
          case GL_LINE_LOOP:
          case GL_LINE_STRIP:
          case GL_TRIANGLES:
          case GL_TRIANGLE_STRIP:
          case GL_TRIANGLE_FAN:
            break;
          default:
            return gl::error(GL_INVALID_ENUM, false);
        }
    
        if (count < 0)
        {
            return gl::error(GL_INVALID_VALUE, false);
        }
    
        // Check for mapped buffers
        if (state.hasMappedBuffer(GL_ARRAY_BUFFER))
        {
            return gl::error(GL_INVALID_OPERATION, false);
        }
    
        const gl::DepthStencilState &depthStencilState = state.getDepthStencilState();
        if (depthStencilState.stencilWritemask != depthStencilState.stencilBackWritemask ||
            state.getStencilRef() != state.getStencilBackRef() ||
            depthStencilState.stencilMask != depthStencilState.stencilBackMask)
        {
            // Note: these separate values are not supported in WebGL, due to D3D's limitations.
            // See Section 6.10 of the WebGL 1.0 spec
            ERR("This ANGLE implementation does not support separate front/back stencil "
                "writemasks, reference values, or stencil mask values.");
            return gl::error(GL_INVALID_OPERATION, false);
        }
    
        const gl::Framebuffer *fbo = state.getDrawFramebuffer();
        if (!fbo || fbo->completeness() != GL_FRAMEBUFFER_COMPLETE)
        {
            return gl::error(GL_INVALID_FRAMEBUFFER_OPERATION, false);
        }
    
        if (state.getCurrentProgramId() == 0)
        {
            return gl::error(GL_INVALID_OPERATION, false);
        }
    
        gl::ProgramBinary *programBinary = state.getCurrentProgramBinary();
        if (!programBinary->validateSamplers(NULL))
        {
            return gl::error(GL_INVALID_OPERATION, false);
        }
    
        // No-op if zero count
        return (count > 0);
    }
    
    bool ValidateDrawArrays(const gl::Context *context, GLenum mode, GLint first, GLsizei count)
    {
        if (first < 0)
        {
            return gl::error(GL_INVALID_VALUE, false);
        }
    
        const State &state = context->getState();
        gl::TransformFeedback *curTransformFeedback = state.getCurrentTransformFeedback();
        if (curTransformFeedback && curTransformFeedback->isStarted() && !curTransformFeedback->isPaused() &&
            curTransformFeedback->getDrawMode() != mode)
        {
            // It is an invalid operation to call DrawArrays or DrawArraysInstanced with a draw mode
            // that does not match the current transform feedback object's draw mode (if transform feedback
            // is active), (3.0.2, section 2.14, pg 86)
            return gl::error(GL_INVALID_OPERATION, false);
        }
    
        if (!ValidateDrawBase(state, mode, count))
        {
            return false;
        }
    
        return true;
    }
    
    bool ValidateDrawArraysInstanced(const gl::Context *context, GLenum mode, GLint first, GLsizei count, GLsizei primcount)
    {
        if (primcount < 0)
        {
            return gl::error(GL_INVALID_VALUE, false);
        }
    
        if (!ValidateDrawArrays(context, mode, first, count))
        {
            return false;
        }
    
        // No-op if zero primitive count
        return (primcount > 0);
    }
    
    bool ValidateDrawElements(const gl::Context *context, GLenum mode, GLsizei count, GLenum type, const GLvoid* indices)
    {
        switch (type)
        {
          case GL_UNSIGNED_BYTE:
          case GL_UNSIGNED_SHORT:
            break;
          case GL_UNSIGNED_INT:
            if (!context->getExtensions().elementIndexUint)
            {
                return gl::error(GL_INVALID_ENUM, false);
            }
            break;
          default:
            return gl::error(GL_INVALID_ENUM, false);
        }
    
        const State &state = context->getState();
    
        gl::TransformFeedback *curTransformFeedback = state.getCurrentTransformFeedback();
        if (curTransformFeedback && curTransformFeedback->isStarted() && !curTransformFeedback->isPaused())
        {
            // It is an invalid operation to call DrawElements, DrawRangeElements or DrawElementsInstanced
            // while transform feedback is active, (3.0.2, section 2.14, pg 86)
            return gl::error(GL_INVALID_OPERATION, false);
        }
    
        // Check for mapped buffers
        if (state.hasMappedBuffer(GL_ELEMENT_ARRAY_BUFFER))
        {
            return gl::error(GL_INVALID_OPERATION, false);
        }
    
        gl::VertexArray *vao = state.getVertexArray();
        if (!indices && !vao->getElementArrayBuffer())
        {
            return gl::error(GL_INVALID_OPERATION, false);
        }
    
        if (!ValidateDrawBase(state, mode, count))
        {
            return false;
        }
    
        return true;
    }
    
    bool ValidateDrawElementsInstanced(const gl::Context *context, GLenum mode, GLsizei count, GLenum type,
                                       const GLvoid *indices, GLsizei primcount)
    {
        if (primcount < 0)
        {
            return gl::error(GL_INVALID_VALUE, false);
        }
    
        if (!ValidateDrawElements(context, mode, count, type, indices))
        {
            return false;
        }
    
        // No-op zero primitive count
        return (primcount > 0);
    }
    
    bool ValidateFramebufferTextureBase(const gl::Context *context, GLenum target, GLenum attachment,
                                        GLuint texture, GLint level)
    {
        if (!ValidFramebufferTarget(target))
        {
            return gl::error(GL_INVALID_ENUM, false);
        }
    
        if (!ValidateAttachmentTarget(context, attachment))
        {
            return false;
        }
    
        if (texture != 0)
        {
            gl::Texture *tex = context->getTexture(texture);
    
            if (tex == NULL)
            {
                return gl::error(GL_INVALID_OPERATION, false);
            }
    
            if (level < 0)
            {
                return gl::error(GL_INVALID_VALUE, false);
            }
        }
    
        const gl::Framebuffer *framebuffer = context->getState().getTargetFramebuffer(target);
        GLuint framebufferHandle = context->getState().getTargetFramebuffer(target)->id();
    
        if (framebufferHandle == 0 || !framebuffer)
        {
            return gl::error(GL_INVALID_OPERATION, false);
        }
    
        return true;
    }
    
    bool ValidateFramebufferTexture2D(const gl::Context *context, GLenum target, GLenum attachment,
                                      GLenum textarget, GLuint texture, GLint level)
    {
        // Attachments are required to be bound to level 0 in ES2
        if (context->getClientVersion() < 3 && level != 0)
        {
            return gl::error(GL_INVALID_VALUE, false);
        }
    
        if (!ValidateFramebufferTextureBase(context, target, attachment, texture, level))
        {
            return false;
        }
    
        if (texture != 0)
        {
            gl::Texture *tex = context->getTexture(texture);
            ASSERT(tex);
    
            const gl::Caps &caps = context->getCaps();
    
            switch (textarget)
            {
              case GL_TEXTURE_2D:
                {
                    if (level > gl::log2(caps.max2DTextureSize))
                    {
                        return gl::error(GL_INVALID_VALUE, false);
                    }
                    if (tex->getTarget() != GL_TEXTURE_2D)
                    {
                        return gl::error(GL_INVALID_OPERATION, false);
                    }
                    gl::Texture2D *tex2d = static_cast<gl::Texture2D *>(tex);
                    if (tex2d->isCompressed(level))
                    {
                        return gl::error(GL_INVALID_OPERATION, false);
                    }
                }
                break;
    
              case GL_TEXTURE_CUBE_MAP_POSITIVE_X:
              case GL_TEXTURE_CUBE_MAP_NEGATIVE_X:
              case GL_TEXTURE_CUBE_MAP_POSITIVE_Y:
              case GL_TEXTURE_CUBE_MAP_NEGATIVE_Y:
              case GL_TEXTURE_CUBE_MAP_POSITIVE_Z:
              case GL_TEXTURE_CUBE_MAP_NEGATIVE_Z:
                {
                    if (level > gl::log2(caps.maxCubeMapTextureSize))
                    {
                        return gl::error(GL_INVALID_VALUE, false);
                    }
                    if (tex->getTarget() != GL_TEXTURE_CUBE_MAP)
                    {
                        return gl::error(GL_INVALID_OPERATION, false);
                    }
                    gl::TextureCubeMap *texcube = static_cast<gl::TextureCubeMap *>(tex);
                    if (texcube->isCompressed(textarget, level))
                    {
                        return gl::error(GL_INVALID_OPERATION, false);
                    }
                }
                break;
    
              default:
                return gl::error(GL_INVALID_ENUM, false);
            }
        }
    
        return true;
    }
    
    }