kc3-lang/angle/src/compiler/translator/BuiltInFunctionEmulatorGLSL.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>

• src/compiler/translator/BuiltInFunctionEmulatorGLSL.cpp

• //
  // Copyright 2002 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 "compiler/translator/BuiltInFunctionEmulatorGLSL.h"
  
  #include "angle_gl.h"
  #include "compiler/translator/BuiltInFunctionEmulator.h"
  #include "compiler/translator/VersionGLSL.h"
  #include "compiler/translator/tree_util/BuiltIn_autogen.h"
  
  namespace sh
  {
  
  void InitBuiltInAbsFunctionEmulatorForGLSLWorkarounds(BuiltInFunctionEmulator *emu,
                                                        sh::GLenum shaderType)
  {
      if (shaderType == GL_VERTEX_SHADER)
      {
          emu->addEmulatedFunction(BuiltInId::abs_Int1, "int abs_emu(int x) { return x * sign(x); }");
      }
  }
  
  void InitBuiltInIsnanFunctionEmulatorForGLSLWorkarounds(BuiltInFunctionEmulator *emu,
                                                          int targetGLSLVersion)
  {
      // isnan() is supported since GLSL 1.3.
      if (targetGLSLVersion < GLSL_VERSION_130)
          return;
  
      // !(x > 0.0 || x < 0.0 || x == 0.0) will be optimized and always equal to false.
      emu->addEmulatedFunction(
          BuiltInId::isnan_Float1,
          "bool isnan_emu(float x) { return (x > 0.0 || x < 0.0) ? false : x != 0.0; }");
      emu->addEmulatedFunction(
          BuiltInId::isnan_Float2,
          "bvec2 isnan_emu(vec2 x)\n"
          "{\n"
          "    bvec2 isnan;\n"
          "    for (int i = 0; i < 2; i++)\n"
          "    {\n"
          "        isnan[i] = (x[i] > 0.0 || x[i] < 0.0) ? false : x[i] != 0.0;\n"
          "    }\n"
          "    return isnan;\n"
          "}\n");
      emu->addEmulatedFunction(
          BuiltInId::isnan_Float3,
          "bvec3 isnan_emu(vec3 x)\n"
          "{\n"
          "    bvec3 isnan;\n"
          "    for (int i = 0; i < 3; i++)\n"
          "    {\n"
          "        isnan[i] = (x[i] > 0.0 || x[i] < 0.0) ? false : x[i] != 0.0;\n"
          "    }\n"
          "    return isnan;\n"
          "}\n");
      emu->addEmulatedFunction(
          BuiltInId::isnan_Float4,
          "bvec4 isnan_emu(vec4 x)\n"
          "{\n"
          "    bvec4 isnan;\n"
          "    for (int i = 0; i < 4; i++)\n"
          "    {\n"
          "        isnan[i] = (x[i] > 0.0 || x[i] < 0.0) ? false : x[i] != 0.0;\n"
          "    }\n"
          "    return isnan;\n"
          "}\n");
  }
  
  void InitBuiltInAtanFunctionEmulatorForGLSLWorkarounds(BuiltInFunctionEmulator *emu)
  {
      emu->addEmulatedFunction(BuiltInId::atan_Float1_Float1,
                               "emu_precision float atan_emu(emu_precision float y, emu_precision "
                               "float x)\n"
                               "{\n"
                               "    if (x > 0.0) return atan(y / x);\n"
                               "    else if (x < 0.0 && y >= 0.0) return atan(y / x) + 3.14159265;\n"
                               "    else if (x < 0.0 && y < 0.0) return atan(y / x) - 3.14159265;\n"
                               "    else return 1.57079632 * sign(y);\n"
                               "}\n");
      static const std::array<TSymbolUniqueId, 4> ids = {
          BuiltInId::atan_Float1_Float1,
          BuiltInId::atan_Float2_Float2,
          BuiltInId::atan_Float3_Float3,
          BuiltInId::atan_Float4_Float4,
      };
      for (int dim = 2; dim <= 4; ++dim)
      {
          std::stringstream ss = sh::InitializeStream<std::stringstream>();
          ss << "emu_precision vec" << dim << " atan_emu(emu_precision vec" << dim
             << " y, emu_precision vec" << dim << " x)\n"
             << "{\n"
                "    return vec"
             << dim << "(";
          for (int i = 0; i < dim; ++i)
          {
              ss << "atan_emu(y[" << i << "], x[" << i << "])";
              if (i < dim - 1)
              {
                  ss << ", ";
              }
          }
          ss << ");\n"
                "}\n";
          emu->addEmulatedFunctionWithDependency(BuiltInId::atan_Float1_Float1, ids[dim - 1],
                                                 ss.str().c_str());
      }
  }
  
  // Emulate built-in functions missing from GLSL 1.30 and higher
  void InitBuiltInFunctionEmulatorForGLSLMissingFunctions(BuiltInFunctionEmulator *emu,
                                                          sh::GLenum shaderType,
                                                          int targetGLSLVersion)
  {
      // Emulate packUnorm2x16 and unpackUnorm2x16 (GLSL 4.10)
      if (targetGLSLVersion < GLSL_VERSION_410)
      {
          // clang-format off
          emu->addEmulatedFunction(BuiltInId::packUnorm2x16_Float2,
              "uint packUnorm2x16_emu(vec2 v)\n"
              "{\n"
              "    int x = int(round(clamp(v.x, 0.0, 1.0) * 65535.0));\n"
              "    int y = int(round(clamp(v.y, 0.0, 1.0) * 65535.0));\n"
              "    return uint((y << 16) | (x & 0xFFFF));\n"
              "}\n");
  
          emu->addEmulatedFunction(BuiltInId::unpackUnorm2x16_UInt1,
              "vec2 unpackUnorm2x16_emu(uint u)\n"
              "{\n"
              "    float x = float(u & 0xFFFFu) / 65535.0;\n"
              "    float y = float(u >> 16) / 65535.0;\n"
              "    return vec2(x, y);\n"
              "}\n");
          // clang-format on
      }
  
      // Emulate packSnorm2x16, packHalf2x16, unpackSnorm2x16, and unpackHalf2x16 (GLSL 4.20)
      // by using floatBitsToInt, floatBitsToUint, intBitsToFloat, and uintBitsToFloat (GLSL 3.30).
      if (targetGLSLVersion >= GLSL_VERSION_330 && targetGLSLVersion < GLSL_VERSION_420)
      {
          // clang-format off
          emu->addEmulatedFunction(BuiltInId::packSnorm2x16_Float2,
              "uint packSnorm2x16_emu(vec2 v)\n"
              "{\n"
              "    #if defined(GL_ARB_shading_language_packing)\n"
              "        return packSnorm2x16(v);\n"
              "    #else\n"
              "        int x = int(round(clamp(v.x, -1.0, 1.0) * 32767.0));\n"
              "        int y = int(round(clamp(v.y, -1.0, 1.0) * 32767.0));\n"
              "        return uint((y << 16) | (x & 0xFFFF));\n"
              "    #endif\n"
              "}\n");
          emu->addEmulatedFunction(BuiltInId::unpackSnorm2x16_UInt1,
              "#if !defined(GL_ARB_shading_language_packing)\n"
              "    float fromSnorm(uint x)\n"
              "    {\n"
              "        int xi = (int(x) & 0x7FFF) - (int(x) & 0x8000);\n"
              "        return clamp(float(xi) / 32767.0, -1.0, 1.0);\n"
              "    }\n"
              "#endif\n"
              "\n"
              "vec2 unpackSnorm2x16_emu(uint u)\n"
              "{\n"
              "    #if defined(GL_ARB_shading_language_packing)\n"
              "        return unpackSnorm2x16(u);\n"
              "    #else\n"
              "        uint y = (u >> 16);\n"
              "        uint x = u;\n"
              "        return vec2(fromSnorm(x), fromSnorm(y));\n"
              "    #endif\n"
              "}\n");
          // Functions uint f32tof16(float val) and float f16tof32(uint val) are
          // based on the OpenGL redbook Appendix Session "Floating-Point Formats Used in OpenGL".
          emu->addEmulatedFunction(BuiltInId::packHalf2x16_Float2,
              "#if !defined(GL_ARB_shading_language_packing)\n"
              "    uint f32tof16(float val)\n"
              "    {\n"
              "        uint f32 = floatBitsToUint(val);\n"
              "        uint f16 = 0u;\n"
              "        uint sign = (f32 >> 16) & 0x8000u;\n"
              "        int exponent = int((f32 >> 23) & 0xFFu) - 127;\n"
              "        uint mantissa = f32 & 0x007FFFFFu;\n"
              "        if (exponent == 128)\n"
              "        {\n"
              "            // Infinity or NaN\n"
              "            // NaN bits that are masked out by 0x3FF get discarded.\n"
              "            // This can turn some NaNs to infinity, but this is allowed by the spec.\n"
              "            f16 = sign | (0x1Fu << 10);\n"
              "            f16 |= (mantissa & 0x3FFu);\n"
              "        }\n"
              "        else if (exponent > 15)\n"
              "        {\n"
              "            // Overflow - flush to Infinity\n"
              "            f16 = sign | (0x1Fu << 10);\n"
              "        }\n"
              "        else if (exponent > -15)\n"
              "        {\n"
              "            // Representable value\n"
              "            exponent += 15;\n"
              "            mantissa >>= 13;\n"
              "            f16 = sign | uint(exponent << 10) | mantissa;\n"
              "        }\n"
              "        else\n"
              "        {\n"
              "            f16 = sign;\n"
              "        }\n"
              "        return f16;\n"
              "    }\n"
              "#endif\n"
              "\n"
              "uint packHalf2x16_emu(vec2 v)\n"
              "{\n"
              "    #if defined(GL_ARB_shading_language_packing)\n"
              "        return packHalf2x16(v);\n"
              "    #else\n"
              "        uint x = f32tof16(v.x);\n"
              "        uint y = f32tof16(v.y);\n"
              "        return (y << 16) | x;\n"
              "    #endif\n"
              "}\n");
          emu->addEmulatedFunction(BuiltInId::unpackHalf2x16_UInt1,
              "#if !defined(GL_ARB_shading_language_packing)\n"
              "    float f16tof32(uint val)\n"
              "    {\n"
              "        uint sign = (val & 0x8000u) << 16;\n"
              "        int exponent = int((val & 0x7C00u) >> 10);\n"
              "        uint mantissa = val & 0x03FFu;\n"
              "        float f32 = 0.0;\n"
              "        if(exponent == 0)\n"
              "        {\n"
              "            if (mantissa != 0u)\n"
              "            {\n"
              "                const float scale = 1.0 / (1 << 24);\n"
              "                f32 = scale * mantissa;\n"
              "            }\n"
              "        }\n"
              "        else if (exponent == 31)\n"
              "        {\n"
              "            return uintBitsToFloat(sign | 0x7F800000u | mantissa);\n"
              "        }\n"
              "        else\n"
              "        {\n"
              "            exponent -= 15;\n"
              "            float scale;\n"
              "            if(exponent < 0)\n"
              "            {\n"
              "                // The negative unary operator is buggy on OSX.\n"
              "                // Work around this by using abs instead.\n"
              "                scale = 1.0 / (1 << abs(exponent));\n"
              "            }\n"
              "            else\n"
              "            {\n"
              "                scale = 1 << exponent;\n"
              "            }\n"
              "            float decimal = 1.0 + float(mantissa) / float(1 << 10);\n"
              "            f32 = scale * decimal;\n"
              "        }\n"
              "\n"
              "        if (sign != 0u)\n"
              "        {\n"
              "            f32 = -f32;\n"
              "        }\n"
              "\n"
              "        return f32;\n"
              "    }\n"
              "#endif\n"
              "\n"
              "vec2 unpackHalf2x16_emu(uint u)\n"
              "{\n"
              "    #if defined(GL_ARB_shading_language_packing)\n"
              "        return unpackHalf2x16(u);\n"
              "    #else\n"
              "        uint y = (u >> 16);\n"
              "        uint x = u & 0xFFFFu;\n"
              "        return vec2(f16tof32(x), f16tof32(y));\n"
              "    #endif\n"
              "}\n");
          // clang-format on
      }
  }
  
  }  // namespace sh