gecko-dev/gfx/gl/GLBlitHelper.cpp

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#include "gfxUtils.h"
#include "GLBlitHelper.h"
#include "GLContext.h"
#include "GLScreenBuffer.h"
#include "ScopedGLHelpers.h"
#include "mozilla/Preferences.h"
#include "ImageContainer.h"
#include "HeapCopyOfStackArray.h"
#include "mozilla/ArrayUtils.h"
#include "mozilla/gfx/Logging.h"
#include "mozilla/gfx/Matrix.h"
#include "mozilla/UniquePtr.h"
#include "GPUVideoImage.h"

#ifdef MOZ_WIDGET_ANDROID
#  include "GeneratedJNIWrappers.h"
#  include "AndroidSurfaceTexture.h"
#  include "GLImages.h"
#  include "GLLibraryEGL.h"
#endif

#ifdef XP_MACOSX
#  include "MacIOSurfaceImage.h"
#  include "GLContextCGL.h"
#endif

using mozilla::layers::PlanarYCbCrData;
using mozilla::layers::PlanarYCbCrImage;

namespace mozilla {
namespace gl {

// --

const char* const kFragHeader_Tex2D =
    "\
    #define SAMPLER sampler2D                                                \n\
    #if __VERSION__ >= 130                                                   \n\
        #define TEXTURE texture                                              \n\
    #else                                                                    \n\
        #define TEXTURE texture2D                                            \n\
    #endif                                                                   \n\
";
const char* const kFragHeader_Tex2DRect =
    "\
    #define SAMPLER sampler2DRect                                            \n\
    #if __VERSION__ >= 130                                                   \n\
        #define TEXTURE texture                                              \n\
    #else                                                                    \n\
        #define TEXTURE texture2DRect                                        \n\
    #endif                                                                   \n\
";
const char* const kFragHeader_TexExt =
    "\
    #extension GL_OES_EGL_image_external : require                           \n\
    #if __VERSION__ >= 130                                                   \n\
        #define TEXTURE texture                                              \n\
    #else                                                                    \n\
        #define TEXTURE texture2D                                            \n\
    #endif                                                                   \n\
    #define SAMPLER samplerExternalOES                                       \n\
";

const char* const kFragBody_RGBA =
    "\
    VARYING vec2 vTexCoord0;                                                 \n\
    uniform SAMPLER uTex0;                                                   \n\
                                                                             \n\
    void main(void)                                                          \n\
    {                                                                        \n\
        FRAG_COLOR = TEXTURE(uTex0, vTexCoord0);                             \n\
    }                                                                        \n\
";
const char* const kFragBody_CrYCb =
    "\
    VARYING vec2 vTexCoord0;                                                 \n\
    uniform SAMPLER uTex0;                                                   \n\
    uniform MAT4X3 uColorMatrix;                                             \n\
                                                                             \n\
    void main(void)                                                          \n\
    {                                                                        \n\
        vec4 yuv = vec4(TEXTURE(uTex0, vTexCoord0).gbr,                      \n\
                        1.0);                                                \n\
        FRAG_COLOR = vec4((uColorMatrix * yuv).rgb, 1.0);                    \n\
    }                                                                        \n\
";
const char* const kFragBody_NV12 =
    "\
    VARYING vec2 vTexCoord0;                                                 \n\
    VARYING vec2 vTexCoord1;                                                 \n\
    uniform SAMPLER uTex0;                                                   \n\
    uniform SAMPLER uTex1;                                                   \n\
    uniform MAT4X3 uColorMatrix;                                             \n\
                                                                             \n\
    void main(void)                                                          \n\
    {                                                                        \n\
        vec4 yuv = vec4(TEXTURE(uTex0, vTexCoord0).x,                        \n\
                        TEXTURE(uTex1, vTexCoord1).xy,                       \n\
                        1.0);                                                \n\
        FRAG_COLOR = vec4((uColorMatrix * yuv).rgb, 1.0);                    \n\
    }                                                                        \n\
";
const char* const kFragBody_PlanarYUV =
    "\
    VARYING vec2 vTexCoord0;                                                 \n\
    VARYING vec2 vTexCoord1;                                                 \n\
    uniform SAMPLER uTex0;                                                   \n\
    uniform SAMPLER uTex1;                                                   \n\
    uniform SAMPLER uTex2;                                                   \n\
    uniform MAT4X3 uColorMatrix;                                             \n\
                                                                             \n\
    void main(void)                                                          \n\
    {                                                                        \n\
        vec4 yuv = vec4(TEXTURE(uTex0, vTexCoord0).x,                        \n\
                        TEXTURE(uTex1, vTexCoord1).x,                        \n\
                        TEXTURE(uTex2, vTexCoord1).x,                        \n\
                        1.0);                                                \n\
        FRAG_COLOR = vec4((uColorMatrix * yuv).rgb, 1.0);                    \n\
    }                                                                        \n\
";

// --

template <uint8_t N>
/*static*/ Mat<N> Mat<N>::Zero() {
  Mat<N> ret;
  for (auto& x : ret.m) {
    x = 0.0f;
  }
  return ret;
}

template <uint8_t N>
/*static*/ Mat<N> Mat<N>::I() {
  auto ret = Mat<N>::Zero();
  for (uint8_t i = 0; i < N; i++) {
    ret.at(i, i) = 1.0f;
  }
  return ret;
}

template <uint8_t N>
Mat<N> Mat<N>::operator*(const Mat<N>& r) const {
  Mat<N> ret;
  for (uint8_t x = 0; x < N; x++) {
    for (uint8_t y = 0; y < N; y++) {
      float sum = 0.0f;
      for (uint8_t i = 0; i < N; i++) {
        sum += at(i, y) * r.at(x, i);
      }
      ret.at(x, y) = sum;
    }
  }
  return ret;
}

Mat3 SubRectMat3(const float x, const float y, const float w, const float h) {
  auto ret = Mat3::Zero();
  ret.at(0, 0) = w;
  ret.at(1, 1) = h;
  ret.at(2, 0) = x;
  ret.at(2, 1) = y;
  ret.at(2, 2) = 1.0f;
  return ret;
}

Mat3 SubRectMat3(const gfx::IntRect& subrect, const gfx::IntSize& size) {
  return SubRectMat3(float(subrect.X()) / size.width,
                     float(subrect.Y()) / size.height,
                     float(subrect.Width()) / size.width,
                     float(subrect.Height()) / size.height);
}

Mat3 SubRectMat3(const gfx::IntRect& bigSubrect, const gfx::IntSize& smallSize,
                 const gfx::IntSize& divisors) {
  const float x = float(bigSubrect.X()) / divisors.width;
  const float y = float(bigSubrect.Y()) / divisors.height;
  const float w = float(bigSubrect.Width()) / divisors.width;
  const float h = float(bigSubrect.Height()) / divisors.height;
  return SubRectMat3(x / smallSize.width, y / smallSize.height,
                     w / smallSize.width, h / smallSize.height);
}

// --

ScopedSaveMultiTex::ScopedSaveMultiTex(GLContext* const gl,
                                       const uint8_t texCount,
                                       const GLenum texTarget)
    : mGL(*gl),
      mTexCount(texCount),
      mTexTarget(texTarget),
      mOldTexUnit(mGL.GetIntAs<GLenum>(LOCAL_GL_ACTIVE_TEXTURE)) {
  GLenum texBinding;
  switch (mTexTarget) {
    case LOCAL_GL_TEXTURE_2D:
      texBinding = LOCAL_GL_TEXTURE_BINDING_2D;
      break;
    case LOCAL_GL_TEXTURE_RECTANGLE:
      texBinding = LOCAL_GL_TEXTURE_BINDING_RECTANGLE;
      break;
    case LOCAL_GL_TEXTURE_EXTERNAL:
      texBinding = LOCAL_GL_TEXTURE_BINDING_EXTERNAL;
      break;
    default:
      gfxCriticalError() << "Unhandled texTarget: " << texTarget;
  }

  for (uint8_t i = 0; i < mTexCount; i++) {
    mGL.fActiveTexture(LOCAL_GL_TEXTURE0 + i);
    if (mGL.IsSupported(GLFeature::sampler_objects)) {
      mOldTexSampler[i] = mGL.GetIntAs<GLuint>(LOCAL_GL_SAMPLER_BINDING);
      mGL.fBindSampler(i, 0);
    }
    mOldTex[i] = mGL.GetIntAs<GLuint>(texBinding);
  }
}

ScopedSaveMultiTex::~ScopedSaveMultiTex() {
  for (uint8_t i = 0; i < mTexCount; i++) {
    mGL.fActiveTexture(LOCAL_GL_TEXTURE0 + i);
    if (mGL.IsSupported(GLFeature::sampler_objects)) {
      mGL.fBindSampler(i, mOldTexSampler[i]);
    }
    mGL.fBindTexture(mTexTarget, mOldTex[i]);
  }
  mGL.fActiveTexture(mOldTexUnit);
}

// --

class ScopedBindArrayBuffer final {
  GLContext& mGL;
  const GLuint mOldVBO;

 public:
  ScopedBindArrayBuffer(GLContext* const gl, const GLuint vbo)
      : mGL(*gl), mOldVBO(mGL.GetIntAs<GLuint>(LOCAL_GL_ARRAY_BUFFER_BINDING)) {
    mGL.fBindBuffer(LOCAL_GL_ARRAY_BUFFER, vbo);
  }

  ~ScopedBindArrayBuffer() { mGL.fBindBuffer(LOCAL_GL_ARRAY_BUFFER, mOldVBO); }
};

// --

class ScopedShader final {
  GLContext& mGL;
  const GLuint mName;

 public:
  ScopedShader(GLContext* const gl, const GLenum shaderType)
      : mGL(*gl), mName(mGL.fCreateShader(shaderType)) {}

  ~ScopedShader() { mGL.fDeleteShader(mName); }

  operator GLuint() const { return mName; }
};

// --

class SaveRestoreCurrentProgram final {
  GLContext& mGL;
  const GLuint mOld;

 public:
  explicit SaveRestoreCurrentProgram(GLContext* const gl)
      : mGL(*gl), mOld(mGL.GetIntAs<GLuint>(LOCAL_GL_CURRENT_PROGRAM)) {}

  ~SaveRestoreCurrentProgram() { mGL.fUseProgram(mOld); }
};

// --

class ScopedDrawBlitState final {
  GLContext& mGL;

  const bool blend;
  const bool cullFace;
  const bool depthTest;
  const bool dither;
  const bool polyOffsFill;
  const bool sampleAToC;
  const bool sampleCover;
  const bool scissor;
  const bool stencil;
  Maybe<bool> rasterizerDiscard;

  realGLboolean colorMask[4];
  GLint viewport[4];

 public:
  ScopedDrawBlitState(GLContext* const gl, const gfx::IntSize& destSize)
      : mGL(*gl),
        blend(mGL.PushEnabled(LOCAL_GL_BLEND, false)),
        cullFace(mGL.PushEnabled(LOCAL_GL_CULL_FACE, false)),
        depthTest(mGL.PushEnabled(LOCAL_GL_DEPTH_TEST, false)),
        dither(mGL.PushEnabled(LOCAL_GL_DITHER, true)),
        polyOffsFill(mGL.PushEnabled(LOCAL_GL_POLYGON_OFFSET_FILL, false)),
        sampleAToC(mGL.PushEnabled(LOCAL_GL_SAMPLE_ALPHA_TO_COVERAGE, false)),
        sampleCover(mGL.PushEnabled(LOCAL_GL_SAMPLE_COVERAGE, false)),
        scissor(mGL.PushEnabled(LOCAL_GL_SCISSOR_TEST, false)),
        stencil(mGL.PushEnabled(LOCAL_GL_STENCIL_TEST, false)) {
    if (mGL.IsSupported(GLFeature::transform_feedback2)) {
      // Technically transform_feedback2 requires transform_feedback, which
      // actually adds RASTERIZER_DISCARD.
      rasterizerDiscard =
          Some(mGL.PushEnabled(LOCAL_GL_RASTERIZER_DISCARD, false));
    }

    mGL.fGetBooleanv(LOCAL_GL_COLOR_WRITEMASK, colorMask);
    mGL.fColorMask(true, true, true, true);

    mGL.fGetIntegerv(LOCAL_GL_VIEWPORT, viewport);
    MOZ_ASSERT(destSize.width && destSize.height);
    mGL.fViewport(0, 0, destSize.width, destSize.height);
  }

  ~ScopedDrawBlitState() {
    mGL.SetEnabled(LOCAL_GL_BLEND, blend);
    mGL.SetEnabled(LOCAL_GL_CULL_FACE, cullFace);
    mGL.SetEnabled(LOCAL_GL_DEPTH_TEST, depthTest);
    mGL.SetEnabled(LOCAL_GL_DITHER, dither);
    mGL.SetEnabled(LOCAL_GL_POLYGON_OFFSET_FILL, polyOffsFill);
    mGL.SetEnabled(LOCAL_GL_SAMPLE_ALPHA_TO_COVERAGE, sampleAToC);
    mGL.SetEnabled(LOCAL_GL_SAMPLE_COVERAGE, sampleCover);
    mGL.SetEnabled(LOCAL_GL_SCISSOR_TEST, scissor);
    mGL.SetEnabled(LOCAL_GL_STENCIL_TEST, stencil);
    if (rasterizerDiscard) {
      mGL.SetEnabled(LOCAL_GL_RASTERIZER_DISCARD, rasterizerDiscard.value());
    }

    mGL.fColorMask(colorMask[0], colorMask[1], colorMask[2], colorMask[3]);
    mGL.fViewport(viewport[0], viewport[1], viewport[2], viewport[3]);
  }
};

// --

DrawBlitProg::DrawBlitProg(const GLBlitHelper* const parent, const GLuint prog)
    : mParent(*parent),
      mProg(prog),
      mLoc_uDestMatrix(mParent.mGL->fGetUniformLocation(mProg, "uDestMatrix")),
      mLoc_uTexMatrix0(mParent.mGL->fGetUniformLocation(mProg, "uTexMatrix0")),
      mLoc_uTexMatrix1(mParent.mGL->fGetUniformLocation(mProg, "uTexMatrix1")),
      mLoc_uColorMatrix(
          mParent.mGL->fGetUniformLocation(mProg, "uColorMatrix")) {
  const auto& gl = mParent.mGL;
  MOZ_GL_ASSERT(gl, mLoc_uDestMatrix != -1);
  MOZ_GL_ASSERT(gl, mLoc_uTexMatrix0 != -1);
  if (mLoc_uColorMatrix != -1) {
    MOZ_GL_ASSERT(gl, mLoc_uTexMatrix1 != -1);

    int32_t numActiveUniforms = 0;
    gl->fGetProgramiv(mProg, LOCAL_GL_ACTIVE_UNIFORMS, &numActiveUniforms);

    const size_t kMaxNameSize = 32;
    char name[kMaxNameSize] = {0};
    GLint size = 0;
    GLenum type = 0;
    for (int32_t i = 0; i < numActiveUniforms; i++) {
      gl->fGetActiveUniform(mProg, i, kMaxNameSize, nullptr, &size, &type,
                            name);
      if (strcmp("uColorMatrix", name) == 0) {
        mType_uColorMatrix = type;
        break;
      }
    }
    MOZ_GL_ASSERT(gl, mType_uColorMatrix);
  }
}

DrawBlitProg::~DrawBlitProg() {
  const auto& gl = mParent.mGL;
  if (!gl->MakeCurrent()) return;

  gl->fDeleteProgram(mProg);
}

void DrawBlitProg::Draw(const BaseArgs& args,
                        const YUVArgs* const argsYUV) const {
  const auto& gl = mParent.mGL;

  const SaveRestoreCurrentProgram oldProg(gl);
  gl->fUseProgram(mProg);

  // --

  Mat3 destMatrix;
  if (args.destRect) {
    const auto& destRect = args.destRect.value();
    destMatrix = SubRectMat3(destRect.X() / args.destSize.width,
                             destRect.Y() / args.destSize.height,
                             destRect.Width() / args.destSize.width,
                             destRect.Height() / args.destSize.height);
  } else {
    destMatrix = Mat3::I();
  }

  if (args.yFlip) {
    // Apply the y-flip matrix before the destMatrix.
    // That is, flip y=[0-1] to y=[1-0] before we restrict to the destRect.
    destMatrix.at(2, 1) += destMatrix.at(1, 1);
    destMatrix.at(1, 1) *= -1.0f;
  }

  gl->fUniformMatrix3fv(mLoc_uDestMatrix, 1, false, destMatrix.m);
  gl->fUniformMatrix3fv(mLoc_uTexMatrix0, 1, false, args.texMatrix0.m);

  MOZ_ASSERT(bool(argsYUV) == (mLoc_uColorMatrix != -1));
  if (argsYUV) {
    gl->fUniformMatrix3fv(mLoc_uTexMatrix1, 1, false, argsYUV->texMatrix1.m);

    const auto& colorMatrix =
        gfxUtils::YuvToRgbMatrix4x4ColumnMajor(argsYUV->colorSpace);
    float mat4x3[4 * 3];
    switch (mType_uColorMatrix) {
      case LOCAL_GL_FLOAT_MAT4:
        gl->fUniformMatrix4fv(mLoc_uColorMatrix, 1, false, colorMatrix);
        break;
      case LOCAL_GL_FLOAT_MAT4x3:
        for (int x = 0; x < 4; x++) {
          for (int y = 0; y < 3; y++) {
            mat4x3[3 * x + y] = colorMatrix[4 * x + y];
          }
        }
        gl->fUniformMatrix4x3fv(mLoc_uColorMatrix, 1, false, mat4x3);
        break;
      default:
        gfxCriticalError() << "Bad mType_uColorMatrix: "
                           << gfx::hexa(mType_uColorMatrix);
    }
  }

  // --

  const ScopedDrawBlitState drawState(gl, args.destSize);

  GLuint oldVAO;
  GLint vaa0Enabled;
  GLint vaa0Size;
  GLenum vaa0Type;
  GLint vaa0Normalized;
  GLsizei vaa0Stride;
  GLvoid* vaa0Pointer;
  if (mParent.mQuadVAO) {
    oldVAO = gl->GetIntAs<GLuint>(LOCAL_GL_VERTEX_ARRAY_BINDING);
    gl->fBindVertexArray(mParent.mQuadVAO);
  } else {
    // clang-format off
        gl->fGetVertexAttribiv(0, LOCAL_GL_VERTEX_ATTRIB_ARRAY_ENABLED, &vaa0Enabled);
        gl->fGetVertexAttribiv(0, LOCAL_GL_VERTEX_ATTRIB_ARRAY_SIZE, &vaa0Size);
        gl->fGetVertexAttribiv(0, LOCAL_GL_VERTEX_ATTRIB_ARRAY_TYPE, (GLint*)&vaa0Type);
        gl->fGetVertexAttribiv(0, LOCAL_GL_VERTEX_ATTRIB_ARRAY_NORMALIZED, &vaa0Normalized);
        gl->fGetVertexAttribiv(0, LOCAL_GL_VERTEX_ATTRIB_ARRAY_STRIDE, (GLint*)&vaa0Stride);
        gl->fGetVertexAttribPointerv(0, LOCAL_GL_VERTEX_ATTRIB_ARRAY_POINTER, &vaa0Pointer);
    // clang-format on

    gl->fEnableVertexAttribArray(0);
    const ScopedBindArrayBuffer bindVBO(gl, mParent.mQuadVBO);
    gl->fVertexAttribPointer(0, 2, LOCAL_GL_FLOAT, false, 0, 0);
  }

  gl->fDrawArrays(LOCAL_GL_TRIANGLE_STRIP, 0, 4);

  if (mParent.mQuadVAO) {
    gl->fBindVertexArray(oldVAO);
  } else {
    if (vaa0Enabled) {
      gl->fEnableVertexAttribArray(0);
    } else {
      gl->fDisableVertexAttribArray(0);
    }
    gl->fVertexAttribPointer(0, vaa0Size, vaa0Type, bool(vaa0Normalized),
                             vaa0Stride, vaa0Pointer);
  }
}

// --

GLBlitHelper::GLBlitHelper(GLContext* const gl)
    : mGL(gl),
      mDrawBlitProg_VertShader(mGL->fCreateShader(LOCAL_GL_VERTEX_SHADER))
//, mYuvUploads_YSize(0, 0)
//, mYuvUploads_UVSize(0, 0)
{
  mGL->fGenBuffers(1, &mQuadVBO);
  {
    const ScopedBindArrayBuffer bindVBO(mGL, mQuadVBO);

    const float quadData[] = {0, 0, 1, 0, 0, 1, 1, 1};
    const HeapCopyOfStackArray<float> heapQuadData(quadData);
    mGL->fBufferData(LOCAL_GL_ARRAY_BUFFER, heapQuadData.ByteLength(),
                     heapQuadData.Data(), LOCAL_GL_STATIC_DRAW);

    if (mGL->IsSupported(GLFeature::vertex_array_object)) {
      const auto prev = mGL->GetIntAs<GLuint>(LOCAL_GL_VERTEX_ARRAY_BINDING);

      mGL->fGenVertexArrays(1, &mQuadVAO);
      mGL->fBindVertexArray(mQuadVAO);
      mGL->fEnableVertexAttribArray(0);
      mGL->fVertexAttribPointer(0, 2, LOCAL_GL_FLOAT, false, 0, 0);

      mGL->fBindVertexArray(prev);
    }
  }

  // --

  const auto glslVersion = mGL->ShadingLanguageVersion();

  // Always use 100 on ES because some devices have OES_EGL_image_external but
  // not OES_EGL_image_external_essl3. We could just use 100 in that particular
  // case, but this is a lot easier and is not harmful to other usages.
  if (mGL->IsGLES()) {
    mDrawBlitProg_VersionLine = nsCString("#version 100\n");
  } else if (glslVersion >= 130) {
    mDrawBlitProg_VersionLine = nsPrintfCString("#version %u\n", glslVersion);
  }

  const char kVertSource[] =
      "\
        #if __VERSION__ >= 130                                               \n\
            #define ATTRIBUTE in                                             \n\
            #define VARYING out                                              \n\
        #else                                                                \n\
            #define ATTRIBUTE attribute                                      \n\
            #define VARYING varying                                          \n\
        #endif                                                               \n\
                                                                             \n\
        ATTRIBUTE vec2 aVert; // [0.0-1.0]                                   \n\
                                                                             \n\
        uniform mat3 uDestMatrix;                                            \n\
        uniform mat3 uTexMatrix0;                                            \n\
        uniform mat3 uTexMatrix1;                                            \n\
                                                                             \n\
        VARYING vec2 vTexCoord0;                                             \n\
        VARYING vec2 vTexCoord1;                                             \n\
                                                                             \n\
        void main(void)                                                      \n\
        {                                                                    \n\
            vec2 destPos = (uDestMatrix * vec3(aVert, 1.0)).xy;              \n\
            gl_Position = vec4(destPos * 2.0 - 1.0, 0.0, 1.0);               \n\
                                                                             \n\
            vTexCoord0 = (uTexMatrix0 * vec3(aVert, 1.0)).xy;                \n\
            vTexCoord1 = (uTexMatrix1 * vec3(aVert, 1.0)).xy;                \n\
        }                                                                    \n\
    ";
  const char* const parts[] = {mDrawBlitProg_VersionLine.get(), kVertSource};
  mGL->fShaderSource(mDrawBlitProg_VertShader, ArrayLength(parts), parts,
                     nullptr);
  mGL->fCompileShader(mDrawBlitProg_VertShader);
}

GLBlitHelper::~GLBlitHelper() {
  for (const auto& pair : mDrawBlitProgs) {
    const auto& ptr = pair.second;
    delete ptr;
  }
  mDrawBlitProgs.clear();

  if (!mGL->MakeCurrent()) return;

  mGL->fDeleteShader(mDrawBlitProg_VertShader);
  mGL->fDeleteBuffers(1, &mQuadVBO);

  if (mQuadVAO) {
    mGL->fDeleteVertexArrays(1, &mQuadVAO);
  }
}

// --

const DrawBlitProg* GLBlitHelper::GetDrawBlitProg(
    const DrawBlitProg::Key& key) const {
  const auto& res = mDrawBlitProgs.insert({key, nullptr});
  auto& pair = *(res.first);
  const auto& didInsert = res.second;
  if (didInsert) {
    pair.second = CreateDrawBlitProg(pair.first);
  }
  return pair.second;
}

const DrawBlitProg* GLBlitHelper::CreateDrawBlitProg(
    const DrawBlitProg::Key& key) const {
  const char kFragHeader_Global[] =
      "\
        #ifdef GL_ES                                                         \n\
            #ifdef GL_FRAGMENT_PRECISION_HIGH                                \n\
                precision highp float;                                       \n\
            #else                                                            \n\
                precision mediump float;                                     \n\
            #endif                                                           \n\
        #endif                                                               \n\
                                                                             \n\
        #if __VERSION__ >= 130                                               \n\
            #define VARYING in                                               \n\
            #define FRAG_COLOR oFragColor                                    \n\
            out vec4 FRAG_COLOR;                                             \n\
        #else                                                                \n\
            #define VARYING varying                                          \n\
            #define FRAG_COLOR gl_FragColor                                  \n\
        #endif                                                               \n\
                                                                             \n\
        #if __VERSION__ >= 120                                               \n\
            #define MAT4X3 mat4x3                                            \n\
        #else                                                                \n\
            #define MAT4X3 mat4                                              \n\
        #endif                                                               \n\
    ";

  const ScopedShader fs(mGL, LOCAL_GL_FRAGMENT_SHADER);
  const char* const parts[] = {mDrawBlitProg_VersionLine.get(), key.fragHeader,
                               kFragHeader_Global, key.fragBody};
  mGL->fShaderSource(fs, ArrayLength(parts), parts, nullptr);
  mGL->fCompileShader(fs);

  const auto prog = mGL->fCreateProgram();
  mGL->fAttachShader(prog, mDrawBlitProg_VertShader);
  mGL->fAttachShader(prog, fs);

  mGL->fBindAttribLocation(prog, 0, "aPosition");
  mGL->fLinkProgram(prog);

  GLenum status = 0;
  mGL->fGetProgramiv(prog, LOCAL_GL_LINK_STATUS, (GLint*)&status);
  if (status == LOCAL_GL_TRUE || !mGL->CheckContextLost()) {
    const SaveRestoreCurrentProgram oldProg(mGL);
    mGL->fUseProgram(prog);
    const char* samplerNames[] = {"uTex0", "uTex1", "uTex2"};
    for (int i = 0; i < 3; i++) {
      const auto loc = mGL->fGetUniformLocation(prog, samplerNames[i]);
      if (loc == -1) break;
      mGL->fUniform1i(loc, i);
    }

    return new DrawBlitProg(this, prog);
  }

  GLuint progLogLen = 0;
  mGL->fGetProgramiv(prog, LOCAL_GL_INFO_LOG_LENGTH, (GLint*)&progLogLen);
  const UniquePtr<char[]> progLog(new char[progLogLen + 1]);
  mGL->fGetProgramInfoLog(prog, progLogLen, nullptr, progLog.get());
  progLog[progLogLen] = 0;

  const auto& vs = mDrawBlitProg_VertShader;
  GLuint vsLogLen = 0;
  mGL->fGetShaderiv(vs, LOCAL_GL_INFO_LOG_LENGTH, (GLint*)&vsLogLen);
  const UniquePtr<char[]> vsLog(new char[vsLogLen + 1]);
  mGL->fGetShaderInfoLog(vs, vsLogLen, nullptr, vsLog.get());
  vsLog[vsLogLen] = 0;

  GLuint fsLogLen = 0;
  mGL->fGetShaderiv(fs, LOCAL_GL_INFO_LOG_LENGTH, (GLint*)&fsLogLen);
  const UniquePtr<char[]> fsLog(new char[fsLogLen + 1]);
  mGL->fGetShaderInfoLog(fs, fsLogLen, nullptr, fsLog.get());
  fsLog[fsLogLen] = 0;

  gfxCriticalError() << "DrawBlitProg link failed:\n"
                     << "progLog: " << progLog.get() << "\n"
                     << "vsLog: " << vsLog.get() << "\n"
                     << "fsLog: " << fsLog.get() << "\n";
  MOZ_CRASH();
}

// -----------------------------------------------------------------------------

bool GLBlitHelper::BlitImageToFramebuffer(layers::Image* const srcImage,
                                          const gfx::IntSize& destSize,
                                          const OriginPos destOrigin) {
  switch (srcImage->GetFormat()) {
    case ImageFormat::PLANAR_YCBCR:
      return BlitImage(static_cast<PlanarYCbCrImage*>(srcImage), destSize,
                       destOrigin);

#ifdef MOZ_WIDGET_ANDROID
    case ImageFormat::SURFACE_TEXTURE:
      return BlitImage(static_cast<layers::SurfaceTextureImage*>(srcImage),
                       destSize, destOrigin);
#endif
#ifdef XP_MACOSX
    case ImageFormat::MAC_IOSURFACE:
      return BlitImage(srcImage->AsMacIOSurfaceImage(), destSize, destOrigin);
#endif
#ifdef XP_WIN
    case ImageFormat::GPU_VIDEO:
      return BlitImage(static_cast<layers::GPUVideoImage*>(srcImage), destSize,
                       destOrigin);
    case ImageFormat::D3D11_YCBCR_IMAGE:
      return BlitImage((layers::D3D11YCbCrImage*)srcImage, destSize,
                       destOrigin);
    case ImageFormat::D3D9_RGB32_TEXTURE:
      return false;  // todo
#endif
    default:
      gfxCriticalError() << "Unhandled srcImage->GetFormat(): "
                         << uint32_t(srcImage->GetFormat());
      return false;
  }
}

// -------------------------------------

#ifdef MOZ_WIDGET_ANDROID
bool GLBlitHelper::BlitImage(layers::SurfaceTextureImage* srcImage,
                             const gfx::IntSize& destSize,
                             const OriginPos destOrigin) const {
  AndroidSurfaceTextureHandle handle = srcImage->GetHandle();
  const auto& surfaceTexture = java::GeckoSurfaceTexture::Lookup(handle);

  if (!surfaceTexture) {
    return false;
  }

  const ScopedBindTextureUnit boundTU(mGL, LOCAL_GL_TEXTURE0);

  if (!surfaceTexture->IsAttachedToGLContext((int64_t)mGL)) {
    GLuint tex;
    mGL->MakeCurrent();
    mGL->fGenTextures(1, &tex);

    if (NS_FAILED(surfaceTexture->AttachToGLContext((int64_t)mGL, tex))) {
      mGL->fDeleteTextures(1, &tex);
      return false;
    }
  }

  const ScopedBindTexture savedTex(mGL, surfaceTexture->GetTexName(),
                                   LOCAL_GL_TEXTURE_EXTERNAL);
  surfaceTexture->UpdateTexImage();

  gfx::Matrix4x4 transform4;
  AndroidSurfaceTexture::GetTransformMatrix(
      java::sdk::SurfaceTexture::Ref::From(surfaceTexture), &transform4);
  Mat3 transform3;
  transform3.at(0, 0) = transform4._11;
  transform3.at(0, 1) = transform4._12;
  transform3.at(0, 2) = transform4._14;
  transform3.at(1, 0) = transform4._21;
  transform3.at(1, 1) = transform4._22;
  transform3.at(1, 2) = transform4._24;
  transform3.at(2, 0) = transform4._41;
  transform3.at(2, 1) = transform4._42;
  transform3.at(2, 2) = transform4._44;

  // We don't do w-divison, so if these aren't what we expect, we're probably
  // doing something wrong.
  MOZ_ASSERT(transform3.at(0, 2) == 0);
  MOZ_ASSERT(transform3.at(1, 2) == 0);
  MOZ_ASSERT(transform3.at(2, 2) == 1);

  const auto& srcOrigin = srcImage->GetOriginPos();

  // I honestly have no idea why this logic is flipped, but changing the
  // source origin would mean we'd have to flip it in the compositor
  // which makes just as little sense as this.
  const bool yFlip = (srcOrigin == destOrigin);

  const auto& prog = GetDrawBlitProg({kFragHeader_TexExt, kFragBody_RGBA});

  // There is no padding on these images, so we can use the GetTransformMatrix
  // directly.
  const DrawBlitProg::BaseArgs baseArgs = {transform3, yFlip, destSize,
                                           Nothing()};
  prog->Draw(baseArgs, nullptr);

  if (surfaceTexture->IsSingleBuffer()) {
    surfaceTexture->ReleaseTexImage();
  }

  return true;
}
#endif

// -------------------------------------

bool GuessDivisors(const gfx::IntSize& ySize, const gfx::IntSize& uvSize,
                   gfx::IntSize* const out_divisors) {
  const gfx::IntSize divisors((ySize.width == uvSize.width) ? 1 : 2,
                              (ySize.height == uvSize.height) ? 1 : 2);
  if (uvSize.width * divisors.width != ySize.width ||
      uvSize.height * divisors.height != ySize.height) {
    return false;
  }
  *out_divisors = divisors;
  return true;
}

bool GLBlitHelper::BlitImage(layers::PlanarYCbCrImage* const yuvImage,
                             const gfx::IntSize& destSize,
                             const OriginPos destOrigin) {
  const auto& prog = GetDrawBlitProg({kFragHeader_Tex2D, kFragBody_PlanarYUV});

  if (!mYuvUploads[0]) {
    mGL->fGenTextures(3, mYuvUploads);
    const ScopedBindTexture bindTex(mGL, mYuvUploads[0]);
    mGL->TexParams_SetClampNoMips();
    mGL->fBindTexture(LOCAL_GL_TEXTURE_2D, mYuvUploads[1]);
    mGL->TexParams_SetClampNoMips();
    mGL->fBindTexture(LOCAL_GL_TEXTURE_2D, mYuvUploads[2]);
    mGL->TexParams_SetClampNoMips();
  }

  // --

  const PlanarYCbCrData* const yuvData = yuvImage->GetData();

  if (yuvData->mYSkip || yuvData->mCbSkip || yuvData->mCrSkip ||
      yuvData->mYSize.width < 0 || yuvData->mYSize.height < 0 ||
      yuvData->mCbCrSize.width < 0 || yuvData->mCbCrSize.height < 0 ||
      yuvData->mYStride < 0 || yuvData->mCbCrStride < 0) {
    gfxCriticalError() << "Unusual PlanarYCbCrData: " << yuvData->mYSkip << ","
                       << yuvData->mCbSkip << "," << yuvData->mCrSkip << ", "
                       << yuvData->mYSize.width << "," << yuvData->mYSize.height
                       << ", " << yuvData->mCbCrSize.width << ","
                       << yuvData->mCbCrSize.height << ", " << yuvData->mYStride
                       << "," << yuvData->mCbCrStride;
    return false;
  }

  gfx::IntSize divisors;
  if (!GuessDivisors(yuvData->mYSize, yuvData->mCbCrSize, &divisors)) {
    gfxCriticalError() << "GuessDivisors failed:" << yuvData->mYSize.width
                       << "," << yuvData->mYSize.height << ", "
                       << yuvData->mCbCrSize.width << ","
                       << yuvData->mCbCrSize.height;
    return false;
  }

  // --

  // RED textures aren't valid in GLES2, and ALPHA textures are not valid in
  // desktop GL Core Profiles. So use R8 textures on GL3.0+ and GLES3.0+, but
  // LUMINANCE/LUMINANCE/UNSIGNED_BYTE otherwise.
  GLenum internalFormat;
  GLenum unpackFormat;
  if (mGL->IsAtLeast(gl::ContextProfile::OpenGLCore, 300) ||
      mGL->IsAtLeast(gl::ContextProfile::OpenGLES, 300)) {
    internalFormat = LOCAL_GL_R8;
    unpackFormat = LOCAL_GL_RED;
  } else {
    internalFormat = LOCAL_GL_LUMINANCE;
    unpackFormat = LOCAL_GL_LUMINANCE;
  }

  // --

  const ScopedSaveMultiTex saveTex(mGL, 3, LOCAL_GL_TEXTURE_2D);
  const ResetUnpackState reset(mGL);
  const gfx::IntSize yTexSize(yuvData->mYStride, yuvData->mYSize.height);
  const gfx::IntSize uvTexSize(yuvData->mCbCrStride, yuvData->mCbCrSize.height);

  if (yTexSize != mYuvUploads_YSize || uvTexSize != mYuvUploads_UVSize) {
    mYuvUploads_YSize = yTexSize;
    mYuvUploads_UVSize = uvTexSize;

    mGL->fActiveTexture(LOCAL_GL_TEXTURE0);
    mGL->fBindTexture(LOCAL_GL_TEXTURE_2D, mYuvUploads[0]);
    mGL->fTexImage2D(LOCAL_GL_TEXTURE_2D, 0, internalFormat, yTexSize.width,
                     yTexSize.height, 0, unpackFormat, LOCAL_GL_UNSIGNED_BYTE,
                     nullptr);
    for (int i = 1; i < 3; i++) {
      mGL->fActiveTexture(LOCAL_GL_TEXTURE0 + i);
      mGL->fBindTexture(LOCAL_GL_TEXTURE_2D, mYuvUploads[i]);
      mGL->fTexImage2D(LOCAL_GL_TEXTURE_2D, 0, internalFormat, uvTexSize.width,
                       uvTexSize.height, 0, unpackFormat,
                       LOCAL_GL_UNSIGNED_BYTE, nullptr);
    }
  }

  // --

  mGL->fActiveTexture(LOCAL_GL_TEXTURE0);
  mGL->fBindTexture(LOCAL_GL_TEXTURE_2D, mYuvUploads[0]);
  mGL->fTexSubImage2D(LOCAL_GL_TEXTURE_2D, 0, 0, 0, yTexSize.width,
                      yTexSize.height, unpackFormat, LOCAL_GL_UNSIGNED_BYTE,
                      yuvData->mYChannel);
  mGL->fActiveTexture(LOCAL_GL_TEXTURE1);
  mGL->fBindTexture(LOCAL_GL_TEXTURE_2D, mYuvUploads[1]);
  mGL->fTexSubImage2D(LOCAL_GL_TEXTURE_2D, 0, 0, 0, uvTexSize.width,
                      uvTexSize.height, unpackFormat, LOCAL_GL_UNSIGNED_BYTE,
                      yuvData->mCbChannel);
  mGL->fActiveTexture(LOCAL_GL_TEXTURE2);
  mGL->fBindTexture(LOCAL_GL_TEXTURE_2D, mYuvUploads[2]);
  mGL->fTexSubImage2D(LOCAL_GL_TEXTURE_2D, 0, 0, 0, uvTexSize.width,
                      uvTexSize.height, unpackFormat, LOCAL_GL_UNSIGNED_BYTE,
                      yuvData->mCrChannel);

  // --

  const auto& clipRect = yuvData->GetPictureRect();
  const auto srcOrigin = OriginPos::BottomLeft;
  const bool yFlip = (destOrigin != srcOrigin);

  const DrawBlitProg::BaseArgs baseArgs = {SubRectMat3(clipRect, yTexSize),
                                           yFlip, destSize, Nothing()};
  const DrawBlitProg::YUVArgs yuvArgs = {
      SubRectMat3(clipRect, uvTexSize, divisors), yuvData->mYUVColorSpace};
  prog->Draw(baseArgs, &yuvArgs);
  return true;
}

// -------------------------------------

#ifdef XP_MACOSX
bool GLBlitHelper::BlitImage(layers::MacIOSurfaceImage* const srcImage,
                             const gfx::IntSize& destSize,
                             const OriginPos destOrigin) const {
  MacIOSurface* const iosurf = srcImage->GetSurface();
  if (mGL->GetContextType() != GLContextType::CGL) {
    MOZ_ASSERT(false);
    return false;
  }
  const auto glCGL = static_cast<GLContextCGL*>(mGL);
  const auto cglContext = glCGL->GetCGLContext();

  const auto& srcOrigin = OriginPos::BottomLeft;

  DrawBlitProg::BaseArgs baseArgs;
  baseArgs.yFlip = (destOrigin != srcOrigin);
  baseArgs.destSize = destSize;

  DrawBlitProg::YUVArgs yuvArgs;
  yuvArgs.colorSpace = YUVColorSpace::BT601;

  const DrawBlitProg::YUVArgs* pYuvArgs = nullptr;

  auto planes = iosurf->GetPlaneCount();
  if (!planes) {
    planes = 1;  // Bad API. No cookie.
  }

  const GLenum texTarget = LOCAL_GL_TEXTURE_RECTANGLE;
  const char* const fragHeader = kFragHeader_Tex2DRect;

  const ScopedSaveMultiTex saveTex(mGL, planes, texTarget);
  const ScopedTexture tex0(mGL);
  const ScopedTexture tex1(mGL);
  const ScopedTexture tex2(mGL);
  const GLuint texs[3] = {tex0, tex1, tex2};

  const auto pixelFormat = iosurf->GetPixelFormat();
  const auto formatChars = (const char*)&pixelFormat;
  const char formatStr[] = {formatChars[3], formatChars[2], formatChars[1],
                            formatChars[0], 0};
  if (mGL->ShouldSpew()) {
    printf_stderr("iosurf format: %s (0x%08x)\n", formatStr,
                  uint32_t(pixelFormat));
  }

  const char* fragBody;
  GLenum internalFormats[3] = {0, 0, 0};
  GLenum unpackFormats[3] = {0, 0, 0};
  GLenum unpackTypes[3] = {LOCAL_GL_UNSIGNED_BYTE, LOCAL_GL_UNSIGNED_BYTE,
                           LOCAL_GL_UNSIGNED_BYTE};
  switch (planes) {
    case 1:
      fragBody = kFragBody_RGBA;
      internalFormats[0] = LOCAL_GL_RGBA;
      unpackFormats[0] = LOCAL_GL_RGBA;
      break;
    case 2:
      fragBody = kFragBody_NV12;
      if (mGL->Version() >= 300) {
        internalFormats[0] = LOCAL_GL_R8;
        unpackFormats[0] = LOCAL_GL_RED;
        internalFormats[1] = LOCAL_GL_RG8;
        unpackFormats[1] = LOCAL_GL_RG;
      } else {
        internalFormats[0] = LOCAL_GL_LUMINANCE;
        unpackFormats[0] = LOCAL_GL_LUMINANCE;
        internalFormats[1] = LOCAL_GL_LUMINANCE_ALPHA;
        unpackFormats[1] = LOCAL_GL_LUMINANCE_ALPHA;
      }
      pYuvArgs = &yuvArgs;
      break;
    case 3:
      fragBody = kFragBody_PlanarYUV;
      if (mGL->Version() >= 300) {
        internalFormats[0] = LOCAL_GL_R8;
        unpackFormats[0] = LOCAL_GL_RED;
      } else {
        internalFormats[0] = LOCAL_GL_LUMINANCE;
        unpackFormats[0] = LOCAL_GL_LUMINANCE;
      }
      internalFormats[1] = internalFormats[0];
      internalFormats[2] = internalFormats[0];
      unpackFormats[1] = unpackFormats[0];
      unpackFormats[2] = unpackFormats[0];
      pYuvArgs = &yuvArgs;
      break;
    default:
      gfxCriticalError() << "Unexpected plane count: " << planes;
      return false;
  }

  if (pixelFormat == '2vuy') {
    fragBody = kFragBody_CrYCb;
    // APPLE_rgb_422 adds RGB_RAW_422_APPLE for `internalFormat`, but only RGB
    // seems to work?
    internalFormats[0] = LOCAL_GL_RGB;
    unpackFormats[0] = LOCAL_GL_RGB_422_APPLE;
    unpackTypes[0] = LOCAL_GL_UNSIGNED_SHORT_8_8_APPLE;
    pYuvArgs = &yuvArgs;
  }

  for (uint32_t p = 0; p < planes; p++) {
    mGL->fActiveTexture(LOCAL_GL_TEXTURE0 + p);
    mGL->fBindTexture(texTarget, texs[p]);
    mGL->TexParams_SetClampNoMips(texTarget);

    const auto width = iosurf->GetDevicePixelWidth(p);
    const auto height = iosurf->GetDevicePixelHeight(p);
    auto err = iosurf->CGLTexImageIOSurface2D(
        cglContext, texTarget, internalFormats[p], width, height,
        unpackFormats[p], unpackTypes[p], p);
    if (err) {
      const nsPrintfCString errStr(
          "CGLTexImageIOSurface2D(context, target, 0x%04x,"
          " %u, %u, 0x%04x, 0x%04x, iosurfPtr, %u) -> %i",
          internalFormats[p], uint32_t(width), uint32_t(height),
          unpackFormats[p], unpackTypes[p], p, err);
      gfxCriticalError() << errStr.get() << " (iosurf format: " << formatStr
                         << ")";
      return false;
    }

    if (p == 0) {
      baseArgs.texMatrix0 = SubRectMat3(0, 0, width, height);
      yuvArgs.texMatrix1 = SubRectMat3(0, 0, width / 2.0, height / 2.0);
    }
  }

  const auto& prog = GetDrawBlitProg({fragHeader, fragBody});
  prog->Draw(baseArgs, pYuvArgs);
  return true;
}
#endif

// -----------------------------------------------------------------------------

void GLBlitHelper::DrawBlitTextureToFramebuffer(const GLuint srcTex,
                                                const gfx::IntSize& srcSize,
                                                const gfx::IntSize& destSize,
                                                const GLenum srcTarget) const {
  const char* fragHeader;
  Mat3 texMatrix0;
  switch (srcTarget) {
    case LOCAL_GL_TEXTURE_2D:
      fragHeader = kFragHeader_Tex2D;
      texMatrix0 = Mat3::I();
      break;
    case LOCAL_GL_TEXTURE_RECTANGLE_ARB:
      fragHeader = kFragHeader_Tex2DRect;
      texMatrix0 = SubRectMat3(0, 0, srcSize.width, srcSize.height);
      break;
    default:
      gfxCriticalError() << "Unexpected srcTarget: " << srcTarget;
      return;
  }
  const auto& prog = GetDrawBlitProg({fragHeader, kFragBody_RGBA});

  const ScopedSaveMultiTex saveTex(mGL, 1, srcTarget);
  mGL->fBindTexture(srcTarget, srcTex);

  const bool yFlip = false;
  const DrawBlitProg::BaseArgs baseArgs = {texMatrix0, yFlip, destSize,
                                           Nothing()};
  prog->Draw(baseArgs);
}

// -----------------------------------------------------------------------------

void GLBlitHelper::BlitFramebuffer(const gfx::IntSize& srcSize,
                                   const gfx::IntSize& destSize,
                                   GLuint filter) const {
  MOZ_ASSERT(mGL->IsSupported(GLFeature::framebuffer_blit));

  const ScopedGLState scissor(mGL, LOCAL_GL_SCISSOR_TEST, false);
  mGL->fBlitFramebuffer(0, 0, srcSize.width, srcSize.height, 0, 0,
                        destSize.width, destSize.height,
                        LOCAL_GL_COLOR_BUFFER_BIT, filter);
}

// --

void GLBlitHelper::BlitFramebufferToFramebuffer(const GLuint srcFB,
                                                const GLuint destFB,
                                                const gfx::IntSize& srcSize,
                                                const gfx::IntSize& destSize,
                                                GLuint filter) const {
  MOZ_ASSERT(mGL->IsSupported(GLFeature::framebuffer_blit));
  MOZ_GL_ASSERT(mGL, !srcFB || mGL->fIsFramebuffer(srcFB));
  MOZ_GL_ASSERT(mGL, !destFB || mGL->fIsFramebuffer(destFB));

  const ScopedBindFramebuffer boundFB(mGL);
  mGL->fBindFramebuffer(LOCAL_GL_READ_FRAMEBUFFER, srcFB);
  mGL->fBindFramebuffer(LOCAL_GL_DRAW_FRAMEBUFFER, destFB);

  BlitFramebuffer(srcSize, destSize, filter);
}

void GLBlitHelper::BlitTextureToFramebuffer(GLuint srcTex,
                                            const gfx::IntSize& srcSize,
                                            const gfx::IntSize& destSize,
                                            GLenum srcTarget) const {
  MOZ_GL_ASSERT(mGL, mGL->fIsTexture(srcTex));

  if (mGL->IsSupported(GLFeature::framebuffer_blit)) {
    const ScopedFramebufferForTexture srcWrapper(mGL, srcTex, srcTarget);
    const ScopedBindFramebuffer bindFB(mGL);
    mGL->fBindFramebuffer(LOCAL_GL_READ_FRAMEBUFFER, srcWrapper.FB());
    BlitFramebuffer(srcSize, destSize);
    return;
  }

  DrawBlitTextureToFramebuffer(srcTex, srcSize, destSize, srcTarget);
}

void GLBlitHelper::BlitFramebufferToTexture(GLuint destTex,
                                            const gfx::IntSize& srcSize,
                                            const gfx::IntSize& destSize,
                                            GLenum destTarget) const {
  MOZ_GL_ASSERT(mGL, mGL->fIsTexture(destTex));

  if (mGL->IsSupported(GLFeature::framebuffer_blit)) {
    const ScopedFramebufferForTexture destWrapper(mGL, destTex, destTarget);
    const ScopedBindFramebuffer bindFB(mGL);
    mGL->fBindFramebuffer(LOCAL_GL_DRAW_FRAMEBUFFER, destWrapper.FB());
    BlitFramebuffer(srcSize, destSize);
    return;
  }

  ScopedBindTexture autoTex(mGL, destTex, destTarget);
  ScopedGLState scissor(mGL, LOCAL_GL_SCISSOR_TEST, false);
  mGL->fCopyTexSubImage2D(destTarget, 0, 0, 0, 0, 0, srcSize.width,
                          srcSize.height);
}

void GLBlitHelper::BlitTextureToTexture(GLuint srcTex, GLuint destTex,
                                        const gfx::IntSize& srcSize,
                                        const gfx::IntSize& destSize,
                                        GLenum srcTarget,
                                        GLenum destTarget) const {
  MOZ_GL_ASSERT(mGL, mGL->fIsTexture(srcTex));
  MOZ_GL_ASSERT(mGL, mGL->fIsTexture(destTex));

  // Start down the CopyTexSubImage path, not the DrawBlit path.
  const ScopedFramebufferForTexture srcWrapper(mGL, srcTex, srcTarget);
  const ScopedBindFramebuffer bindFB(mGL, srcWrapper.FB());
  BlitFramebufferToTexture(destTex, srcSize, destSize, destTarget);
}

}  // namespace gl
}  // namespace mozilla