shader_utils.cpp

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Author : Stuart Morgan
Date : 2019-08-14 12:25:12
Hash : 9d737966
Message : Standardize copyright notices to project style For all "ANGLE Project" copyrights, standardize to the format specified by the style guide. Changes: - "Copyright (c)" and "Copyright(c)" changed to just "Copyright". - Removed the second half of date ranges ("Y1Y1-Y2Y2"->"Y1Y1"). - Fixed a small number of files that had no copyright date using the initial commit year from the version control history. - Fixed one instance of copyright being "The ANGLE Project" rather than "The ANGLE Project Authors" These changes are applied both to the copyright of source file, and where applicable to copyright statements that are generated by templates. BUG=angleproject:3811 Change-Id: I973dd65e4ef9deeba232d5be74c768256a0eb2e5 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/1754397 Commit-Queue: Jamie Madill <jmadill@chromium.org> Reviewed-by: Jamie Madill <jmadill@chromium.org>
util/shader_utils.cpp
//
// Copyright 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.
//

#include "shader_utils.h"

#include <cstring>
#include <fstream>
#include <iostream>
#include <vector>

namespace
{
std::string ReadFileToString(const std::string &source)
{
    std::ifstream stream(source.c_str());
    if (!stream)
    {
        std::cerr << "Failed to load shader file: " << source;
        return "";
    }

    std::string result;

    stream.seekg(0, std::ios::end);
    result.reserve(static_cast<unsigned int>(stream.tellg()));
    stream.seekg(0, std::ios::beg);

    result.assign((std::istreambuf_iterator<char>(stream)), std::istreambuf_iterator<char>());

    return result;
}

GLuint CompileProgramInternal(const char *vsSource,
                              const char *gsSource,
                              const char *fsSource,
                              const std::function<void(GLuint)> &preLinkCallback)
{
    GLuint vs = CompileShader(GL_VERTEX_SHADER, vsSource);
    GLuint fs = CompileShader(GL_FRAGMENT_SHADER, fsSource);

    if (vs == 0 || fs == 0)
    {
        glDeleteShader(fs);
        glDeleteShader(vs);
        return 0;
    }

    GLuint program = glCreateProgram();

    glAttachShader(program, vs);
    glDeleteShader(vs);

    glAttachShader(program, fs);
    glDeleteShader(fs);

    GLuint gs = 0;

    if (strlen(gsSource) > 0)
    {
        gs = CompileShader(GL_GEOMETRY_SHADER_EXT, gsSource);
        if (gs == 0)
        {
            glDeleteShader(vs);
            glDeleteShader(fs);
            glDeleteProgram(program);
            return 0;
        }

        glAttachShader(program, gs);
        glDeleteShader(gs);
    }

    if (preLinkCallback)
    {
        preLinkCallback(program);
    }

    glLinkProgram(program);

    return CheckLinkStatusAndReturnProgram(program, true);
}
}  // namespace

GLuint CompileShader(GLenum type, const char *source)
{
    GLuint shader = glCreateShader(type);

    const char *sourceArray[1] = {source};
    glShaderSource(shader, 1, sourceArray, nullptr);
    glCompileShader(shader);

    GLint compileResult;
    glGetShaderiv(shader, GL_COMPILE_STATUS, &compileResult);

    if (compileResult == 0)
    {
        GLint infoLogLength;
        glGetShaderiv(shader, GL_INFO_LOG_LENGTH, &infoLogLength);

        // Info log length includes the null terminator, so 1 means that the info log is an empty
        // string.
        if (infoLogLength > 1)
        {
            std::vector<GLchar> infoLog(infoLogLength);
            glGetShaderInfoLog(shader, static_cast<GLsizei>(infoLog.size()), nullptr, &infoLog[0]);
            std::cerr << "shader compilation failed: " << &infoLog[0];
        }
        else
        {
            std::cerr << "shader compilation failed. <Empty log message>";
        }

        std::cerr << std::endl;

        glDeleteShader(shader);
        shader = 0;
    }

    return shader;
}

GLuint CompileShaderFromFile(GLenum type, const std::string &sourcePath)
{
    std::string source = ReadFileToString(sourcePath);
    if (source.empty())
    {
        return 0;
    }

    return CompileShader(type, source.c_str());
}

GLuint CheckLinkStatusAndReturnProgram(GLuint program, bool outputErrorMessages)
{
    if (glGetError() != GL_NO_ERROR)
        return 0;

    GLint linkStatus;
    glGetProgramiv(program, GL_LINK_STATUS, &linkStatus);
    if (linkStatus == 0)
    {
        if (outputErrorMessages)
        {
            GLint infoLogLength;
            glGetProgramiv(program, GL_INFO_LOG_LENGTH, &infoLogLength);

            // Info log length includes the null terminator, so 1 means that the info log is an
            // empty string.
            if (infoLogLength > 1)
            {
                std::vector<GLchar> infoLog(infoLogLength);
                glGetProgramInfoLog(program, static_cast<GLsizei>(infoLog.size()), nullptr,
                                    &infoLog[0]);

                std::cerr << "program link failed: " << &infoLog[0];
            }
            else
            {
                std::cerr << "program link failed. <Empty log message>";
            }
        }

        glDeleteProgram(program);
        return 0;
    }

    return program;
}

GLuint CompileProgramWithTransformFeedback(
    const char *vsSource,
    const char *fsSource,
    const std::vector<std::string> &transformFeedbackVaryings,
    GLenum bufferMode)
{
    auto preLink = [&](GLuint program) {
        if (transformFeedbackVaryings.size() > 0)
        {
            std::vector<const char *> constCharTFVaryings;

            for (const std::string &transformFeedbackVarying : transformFeedbackVaryings)
            {
                constCharTFVaryings.push_back(transformFeedbackVarying.c_str());
            }

            glTransformFeedbackVaryings(program,
                                        static_cast<GLsizei>(transformFeedbackVaryings.size()),
                                        &constCharTFVaryings[0], bufferMode);
        }
    };

    return CompileProgramInternal(vsSource, "", fsSource, preLink);
}

GLuint CompileProgram(const char *vsSource, const char *fsSource)
{
    return CompileProgramInternal(vsSource, "", fsSource, nullptr);
}

GLuint CompileProgram(const char *vsSource,
                      const char *fsSource,
                      const std::function<void(GLuint)> &preLinkCallback)
{
    return CompileProgramInternal(vsSource, "", fsSource, preLinkCallback);
}

GLuint CompileProgramWithGS(const char *vsSource, const char *gsSource, const char *fsSource)
{
    return CompileProgramInternal(vsSource, gsSource, fsSource, nullptr);
}

GLuint CompileProgramFromFiles(const std::string &vsPath, const std::string &fsPath)
{
    std::string vsSource = ReadFileToString(vsPath);
    std::string fsSource = ReadFileToString(fsPath);
    if (vsSource.empty() || fsSource.empty())
    {
        return 0;
    }

    return CompileProgram(vsSource.c_str(), fsSource.c_str());
}

GLuint CompileComputeProgram(const char *csSource, bool outputErrorMessages)
{
    GLuint program = glCreateProgram();

    GLuint cs = CompileShader(GL_COMPUTE_SHADER, csSource);
    if (cs == 0)
    {
        glDeleteProgram(program);
        return 0;
    }

    glAttachShader(program, cs);

    glLinkProgram(program);

    return CheckLinkStatusAndReturnProgram(program, outputErrorMessages);
}

GLuint LoadBinaryProgramOES(const std::vector<uint8_t> &binary, GLenum binaryFormat)
{
    GLuint program = glCreateProgram();
    glProgramBinaryOES(program, binaryFormat, binary.data(), static_cast<GLint>(binary.size()));
    return CheckLinkStatusAndReturnProgram(program, true);
}

GLuint LoadBinaryProgramES3(const std::vector<uint8_t> &binary, GLenum binaryFormat)
{
    GLuint program = glCreateProgram();
    glProgramBinary(program, binaryFormat, binary.data(), static_cast<GLint>(binary.size()));
    return CheckLinkStatusAndReturnProgram(program, true);
}

bool LinkAttachedProgram(GLuint program)
{
    glLinkProgram(program);
    return (CheckLinkStatusAndReturnProgram(program, true) != 0);
}

namespace angle
{

namespace essl1_shaders
{

const char *PositionAttrib()
{
    return "a_position";
}
const char *ColorUniform()
{
    return "u_color";
}

const char *Texture2DUniform()
{
    return "u_tex2D";
}

namespace vs
{

// A shader that sets gl_Position to zero.
const char *Zero()
{
    return R"(void main()
{
    gl_Position = vec4(0);
})";
}

// A shader that sets gl_Position to attribute a_position.
const char *Simple()
{
    return R"(precision highp float;
attribute vec4 a_position;

void main()
{
    gl_Position = a_position;
})";
}

// A shader that simply passes through attribute a_position, setting it to gl_Position and varying
// v_position.
const char *Passthrough()
{
    return R"(precision highp float;
attribute vec4 a_position;
varying vec4 v_position;

void main()
{
    gl_Position = a_position;
    v_position = a_position;
})";
}

// A shader that simply passes through attribute a_position, setting it to gl_Position and varying
// texcoord.
const char *Texture2D()
{
    return R"(precision highp float;
attribute vec4 a_position;
varying vec2 v_texCoord;

void main()
{
    gl_Position = vec4(a_position.xy, 0.0, 1.0);
    v_texCoord = a_position.xy * 0.5 + vec2(0.5);
})";
}

}  // namespace vs

namespace fs
{

// A shader that renders a simple checker pattern of red and green. X axis and y axis separate the
// different colors. Needs varying v_position.
const char *Checkered()
{
    return R"(precision highp float;
varying vec4 v_position;

void main()
{
    if (v_position.x * v_position.y > 0.0)
    {
        gl_FragColor = vec4(1.0, 0.0, 0.0, 1.0);
    }
    else
    {
        gl_FragColor = vec4(0.0, 1.0, 0.0, 1.0);
    }
})";
}

// A shader that fills with color taken from uniform named "color".
const char *UniformColor()
{
    return R"(uniform mediump vec4 u_color;
void main(void)
{
    gl_FragColor = u_color;
})";
}

// A shader that fills with 100% opaque red.
const char *Red()
{
    return R"(precision mediump float;

void main()
{
    gl_FragColor = vec4(1.0, 0.0, 0.0, 1.0);
})";
}

// A shader that fills with 100% opaque green.
const char *Green()
{
    return R"(precision mediump float;

void main()
{
    gl_FragColor = vec4(0.0, 1.0, 0.0, 1.0);
})";
}

// A shader that fills with 100% opaque blue.
const char *Blue()
{
    return R"(precision mediump float;

void main()
{
    gl_FragColor = vec4(0.0, 0.0, 1.0, 1.0);
})";
}

// A shader that samples the texture.
const char *Texture2D()
{
    return R"(precision mediump float;
uniform sampler2D u_tex;
varying vec2 v_texCoord;

void main()
{
    gl_FragColor = texture2D(u_tex, v_texCoord);
})";
}

}  // namespace fs
}  // namespace essl1_shaders

namespace essl3_shaders
{

const char *PositionAttrib()
{
    return "a_position";
}

namespace vs
{

// A shader that sets gl_Position to zero.
const char *Zero()
{
    return R"(#version 300 es
void main()
{
    gl_Position = vec4(0);
})";
}

// A shader that sets gl_Position to attribute a_position.
const char *Simple()
{
    return R"(#version 300 es
in vec4 a_position;
void main()
{
    gl_Position = a_position;
})";
}

// A shader that simply passes through attribute a_position, setting it to gl_Position and varying
// v_position.
const char *Passthrough()
{
    return R"(#version 300 es
in vec4 a_position;
out vec4 v_position;
void main()
{
    gl_Position = a_position;
    v_position = a_position;
})";
}

}  // namespace vs

namespace fs
{

// A shader that fills with 100% opaque red.
const char *Red()
{
    return R"(#version 300 es
precision highp float;
out vec4 my_FragColor;
void main()
{
    my_FragColor = vec4(1.0, 0.0, 0.0, 1.0);
})";
}

// A shader that fills with 100% opaque green.
const char *Green()
{
    return R"(#version 300 es
precision highp float;
out vec4 my_FragColor;
void main()
{
    my_FragColor = vec4(0.0, 1.0, 0.0, 1.0);
})";
}

// A shader that fills with 100% opaque blue.
const char *Blue()
{
    return R"(#version 300 es
precision highp float;
out vec4 my_FragColor;
void main()
{
    my_FragColor = vec4(0.0, 0.0, 1.0, 1.0);
})";
}

}  // namespace fs
}  // namespace essl3_shaders

namespace essl31_shaders
{

const char *PositionAttrib()
{
    return "a_position";
}

namespace vs
{

// A shader that sets gl_Position to zero.
const char *Zero()
{
    return R"(#version 310 es
void main()
{
    gl_Position = vec4(0);
})";
}

// A shader that sets gl_Position to attribute a_position.
const char *Simple()
{
    return R"(#version 310 es
in vec4 a_position;
void main()
{
    gl_Position = a_position;
})";
}

// A shader that simply passes through attribute a_position, setting it to gl_Position and varying
// v_position.
const char *Passthrough()
{
    return R"(#version 310 es
in vec4 a_position;
out vec4 v_position;
void main()
{
    gl_Position = a_position;
    v_position = a_position;
})";
}

}  // namespace vs

namespace fs
{

// A shader that fills with 100% opaque red.
const char *Red()
{
    return R"(#version 310 es
precision highp float;
out vec4 my_FragColor;
void main()
{
    my_FragColor = vec4(1.0, 0.0, 0.0, 1.0);
})";
}

}  // namespace fs
}  // namespace essl31_shaders
}  // namespace angle
kc3-lang/angle/util/shader_utils.cpp

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kc3-lang/angle /util/shader_utils.cpp
