/* 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 "OGLShaderProgram.h"
#include <stdint.h>                     // for uint32_t
#include <sstream>                      // for ostringstream
#include "gfxEnv.h"
#include "gfxRect.h"                    // for gfxRect
#include "gfxUtils.h"
#include "mozilla/DebugOnly.h"          // for DebugOnly
#include "mozilla/layers/Compositor.h"  // for BlendOpIsMixBlendMode
#include "nsAString.h"
#include "nsString.h"                   // for nsAutoCString
#include "Layers.h"
#include "GLContext.h"

namespace mozilla {
namespace layers {

using namespace std;

#define GAUSSIAN_KERNEL_HALF_WIDTH 11
#define GAUSSIAN_KERNEL_STEP 0.2

void
AddUniforms(ProgramProfileOGL& aProfile)
{
    // This needs to be kept in sync with the KnownUniformName enum
    static const char *sKnownUniformNames[] = {
        "uLayerTransform",
        "uLayerTransformInverse",
        "uMaskTransform",
        "uBackdropTransform",
        "uLayerRects",
        "uMatrixProj",
        "uTextureTransform",
        "uTextureRects",
        "uRenderTargetOffset",
        "uLayerOpacity",
        "uTexture",
        "uYTexture",
        "uCbTexture",
        "uCrTexture",
        "uBlackTexture",
        "uWhiteTexture",
        "uMaskTexture",
        "uBackdropTexture",
        "uRenderColor",
        "uTexCoordMultiplier",
        "uCbCrTexCoordMultiplier",
        "uTexturePass2",
        "uColorMatrix",
        "uColorMatrixVector",
        "uBlurRadius",
        "uBlurOffset",
        "uBlurAlpha",
        "uBlurGaussianKernel",
        "uSSEdges",
        "uViewportSize",
        "uVisibleCenter",
        "uYuvColorMatrix",
        nullptr
    };

    for (int i = 0; sKnownUniformNames[i] != nullptr; ++i) {
        aProfile.mUniforms[i].mNameString = sKnownUniformNames[i];
        aProfile.mUniforms[i].mName = (KnownUniform::KnownUniformName) i;
    }
}

void
ShaderConfigOGL::SetRenderColor(bool aEnabled)
{
  SetFeature(ENABLE_RENDER_COLOR, aEnabled);
}

void
ShaderConfigOGL::SetTextureTarget(GLenum aTarget)
{
  SetFeature(ENABLE_TEXTURE_EXTERNAL | ENABLE_TEXTURE_RECT, false);
  switch (aTarget) {
  case LOCAL_GL_TEXTURE_EXTERNAL:
    SetFeature(ENABLE_TEXTURE_EXTERNAL, true);
    break;
  case LOCAL_GL_TEXTURE_RECTANGLE_ARB:
    SetFeature(ENABLE_TEXTURE_RECT, true);
    break;
  }
}

void
ShaderConfigOGL::SetRBSwap(bool aEnabled)
{
  SetFeature(ENABLE_TEXTURE_RB_SWAP, aEnabled);
}

void
ShaderConfigOGL::SetNoAlpha(bool aEnabled)
{
  SetFeature(ENABLE_TEXTURE_NO_ALPHA, aEnabled);
}

void
ShaderConfigOGL::SetOpacity(bool aEnabled)
{
  SetFeature(ENABLE_OPACITY, aEnabled);
}

void
ShaderConfigOGL::SetYCbCr(bool aEnabled)
{
  SetFeature(ENABLE_TEXTURE_YCBCR, aEnabled);
  MOZ_ASSERT(!(mFeatures & ENABLE_TEXTURE_NV12));
}

void
ShaderConfigOGL::SetNV12(bool aEnabled)
{
  SetFeature(ENABLE_TEXTURE_NV12, aEnabled);
  MOZ_ASSERT(!(mFeatures & ENABLE_TEXTURE_YCBCR));
}

void
ShaderConfigOGL::SetComponentAlpha(bool aEnabled)
{
  SetFeature(ENABLE_TEXTURE_COMPONENT_ALPHA, aEnabled);
}

void
ShaderConfigOGL::SetColorMatrix(bool aEnabled)
{
  SetFeature(ENABLE_COLOR_MATRIX, aEnabled);
}

void
ShaderConfigOGL::SetBlur(bool aEnabled)
{
  SetFeature(ENABLE_BLUR, aEnabled);
}

void
ShaderConfigOGL::SetMask(bool aEnabled)
{
  SetFeature(ENABLE_MASK, aEnabled);
}

void
ShaderConfigOGL::SetNoPremultipliedAlpha()
{
  SetFeature(ENABLE_NO_PREMUL_ALPHA, true);
}

void
ShaderConfigOGL::SetDEAA(bool aEnabled)
{
  SetFeature(ENABLE_DEAA, aEnabled);
}

void
ShaderConfigOGL::SetCompositionOp(gfx::CompositionOp aOp)
{
  mCompositionOp = aOp;
}

void
ShaderConfigOGL::SetDynamicGeometry(bool aEnabled)
{
  SetFeature(ENABLE_DYNAMIC_GEOMETRY, aEnabled);
}

/* static */ ProgramProfileOGL
ProgramProfileOGL::GetProfileFor(ShaderConfigOGL aConfig)
{
  ProgramProfileOGL result;
  ostringstream fs, vs;

  AddUniforms(result);

  gfx::CompositionOp blendOp = aConfig.mCompositionOp;

  vs << "#ifdef GL_ES" << endl;
  vs << "#define EDGE_PRECISION mediump" << endl;
  vs << "#else" << endl;
  vs << "#define EDGE_PRECISION" << endl;
  vs << "#endif" << endl;
  vs << "uniform mat4 uMatrixProj;" << endl;
  vs << "uniform vec4 uLayerRects[4];" << endl;
  vs << "uniform mat4 uLayerTransform;" << endl;
  if (aConfig.mFeatures & ENABLE_DEAA) {
    vs << "uniform mat4 uLayerTransformInverse;" << endl;
    vs << "uniform EDGE_PRECISION vec3 uSSEdges[4];" << endl;
    vs << "uniform vec2 uVisibleCenter;" << endl;
    vs << "uniform vec2 uViewportSize;" << endl;
  }
  vs << "uniform vec2 uRenderTargetOffset;" << endl;
  vs << "attribute vec4 aCoord;" << endl;
  result.mAttributes.AppendElement(Pair<nsCString, GLuint> {"aCoord", 0});

  if (!(aConfig.mFeatures & ENABLE_RENDER_COLOR)) {
    vs << "uniform mat4 uTextureTransform;" << endl;
    vs << "uniform vec4 uTextureRects[4];" << endl;
    vs << "varying vec2 vTexCoord;" << endl;

    if (aConfig.mFeatures & ENABLE_DYNAMIC_GEOMETRY) {
      vs << "attribute vec2 aTexCoord;" << endl;
      result.mAttributes.AppendElement(Pair<nsCString, GLuint> {"aTexCoord", 1});
    }
  }

  if (BlendOpIsMixBlendMode(blendOp)) {
    vs << "uniform mat4 uBackdropTransform;" << endl;
    vs << "varying vec2 vBackdropCoord;" << endl;
  }

  if (aConfig.mFeatures & ENABLE_MASK) {
    vs << "uniform mat4 uMaskTransform;" << endl;
    vs << "varying vec3 vMaskCoord;" << endl;
  }

  vs << "void main() {" << endl;

  if (aConfig.mFeatures & ENABLE_DYNAMIC_GEOMETRY) {
    vs << "  vec4 finalPosition = vec4(aCoord.xy, 0.0, 1.0);" << endl;
  } else {
    vs << "  int vertexID = int(aCoord.w);" << endl;
    vs << "  vec4 layerRect = uLayerRects[vertexID];" << endl;
    vs << "  vec4 finalPosition = vec4(aCoord.xy * layerRect.zw + layerRect.xy, 0.0, 1.0);" << endl;
  }

  vs << "  finalPosition = uLayerTransform * finalPosition;" << endl;

  if (aConfig.mFeatures & ENABLE_DEAA) {
    // XXX kip - The DEAA shader could be made simpler if we switch to
    //           using dynamic vertex buffers instead of sending everything
    //           in through uniforms.  This would enable passing information
    //           about how to dilate each vertex explicitly and eliminate the
    //           need to extrapolate this with the sub-pixel coverage
    //           calculation in the vertex shader.

    // Calculate the screen space position of this vertex, in screen pixels
    vs << "  vec4 ssPos = finalPosition;" << endl;
    vs << "  ssPos.xy -= uRenderTargetOffset * finalPosition.w;" << endl;
    vs << "  ssPos = uMatrixProj * ssPos;" << endl;
    vs << "  ssPos.xy = ((ssPos.xy/ssPos.w)*0.5+0.5)*uViewportSize;" << endl;

    if (aConfig.mFeatures & ENABLE_MASK ||
        !(aConfig.mFeatures & ENABLE_RENDER_COLOR)) {
      vs << "  vec4 coordAdjusted;" << endl;
      vs << "  coordAdjusted.xy = aCoord.xy;" << endl;
    }

    // It is necessary to dilate edges away from uVisibleCenter to ensure that
    // fragments with less than 50% sub-pixel coverage will be shaded.
    // This offset is applied when the sub-pixel coverage of the vertex is
    // less than 100%.  Expanding by 0.5 pixels in screen space is sufficient
    // to include these pixels.
    vs << "  if (dot(uSSEdges[0], vec3(ssPos.xy, 1.0)) < 1.5 ||" << endl;
    vs << "      dot(uSSEdges[1], vec3(ssPos.xy, 1.0)) < 1.5 ||" << endl;
    vs << "      dot(uSSEdges[2], vec3(ssPos.xy, 1.0)) < 1.5 ||" << endl;
    vs << "      dot(uSSEdges[3], vec3(ssPos.xy, 1.0)) < 1.5) {" << endl;
    // If the shader reaches this branch, then this vertex is on the edge of
    // the layer's visible rect and should be dilated away from the center of
    // the visible rect.  We don't want to hit this for inner facing
    // edges between tiles, as the pixels may be covered twice without clipping
    // against uSSEdges.  If all edges were dilated, it would result in
    // artifacts visible within semi-transparent layers with multiple tiles.
    vs << "    vec4 visibleCenter = uLayerTransform * vec4(uVisibleCenter, 0.0, 1.0);" << endl;
    vs << "    vec2 dilateDir = finalPosition.xy / finalPosition.w - visibleCenter.xy / visibleCenter.w;" << endl;
    vs << "    vec2 offset = sign(dilateDir) * 0.5;" << endl;
    vs << "    finalPosition.xy += offset * finalPosition.w;" << endl;
    if (!(aConfig.mFeatures & ENABLE_RENDER_COLOR)) {
      // We must adjust the texture coordinates to compensate for the dilation
      vs << "    coordAdjusted = uLayerTransformInverse * finalPosition;" << endl;
      vs << "    coordAdjusted /= coordAdjusted.w;" << endl;

      if (!(aConfig.mFeatures & ENABLE_DYNAMIC_GEOMETRY)) {
        vs << "    coordAdjusted.xy -= layerRect.xy;" << endl;
        vs << "    coordAdjusted.xy /= layerRect.zw;" << endl;
      }
    }
    vs << "  }" << endl;

    if (!(aConfig.mFeatures & ENABLE_RENDER_COLOR)) {
      if (aConfig.mFeatures & ENABLE_DYNAMIC_GEOMETRY) {
        vs << "  vTexCoord = (uTextureTransform * vec4(aTexCoord, 0.0, 1.0)).xy;" << endl;
      } else {
        vs << "  vec4 textureRect = uTextureRects[vertexID];" << endl;
        vs << "  vec2 texCoord = coordAdjusted.xy * textureRect.zw + textureRect.xy;" << endl;
        vs << "  vTexCoord = (uTextureTransform * vec4(texCoord, 0.0, 1.0)).xy;" << endl;
      }
    }
  } else if (!(aConfig.mFeatures & ENABLE_RENDER_COLOR)) {
    if (aConfig.mFeatures & ENABLE_DYNAMIC_GEOMETRY) {
      vs << "  vTexCoord = (uTextureTransform * vec4(aTexCoord, 0.0, 1.0)).xy;" << endl;
    } else {
      vs << "  vec4 textureRect = uTextureRects[vertexID];" << endl;
      vs << "  vec2 texCoord = aCoord.xy * textureRect.zw + textureRect.xy;" << endl;
      vs << "  vTexCoord = (uTextureTransform * vec4(texCoord, 0.0, 1.0)).xy;" << endl;
    }
  }

  if (aConfig.mFeatures & ENABLE_MASK) {
    vs << "  vMaskCoord.xy = (uMaskTransform * (finalPosition / finalPosition.w)).xy;" << endl;
    // correct for perspective correct interpolation, see comment in D3D11 shader
    vs << "  vMaskCoord.z = 1.0;" << endl;
    vs << "  vMaskCoord *= finalPosition.w;" << endl;
  }
  vs << "  finalPosition.xy -= uRenderTargetOffset * finalPosition.w;" << endl;
  vs << "  finalPosition = uMatrixProj * finalPosition;" << endl;
  if (BlendOpIsMixBlendMode(blendOp)) {
    // Translate from clip space (-1, 1) to (0..1), apply the backdrop
    // transform, then invert the y-axis.
    vs << "  vBackdropCoord.x = (finalPosition.x + 1.0) / 2.0;" << endl;
    vs << "  vBackdropCoord.y = 1.0 - (finalPosition.y + 1.0) / 2.0;" << endl;
    vs << "  vBackdropCoord = (uBackdropTransform * vec4(vBackdropCoord.xy, 0.0, 1.0)).xy;" << endl;
    vs << "  vBackdropCoord.y = 1.0 - vBackdropCoord.y;" << endl;
  }
  vs << "  gl_Position = finalPosition;" << endl;
  vs << "}" << endl;

  if (aConfig.mFeatures & ENABLE_TEXTURE_RECT) {
    fs << "#extension GL_ARB_texture_rectangle : require" << endl;
  }
  if (aConfig.mFeatures & ENABLE_TEXTURE_EXTERNAL) {
    fs << "#extension GL_OES_EGL_image_external : require" << endl;
  }
  fs << "#ifdef GL_ES" << endl;
  fs << "precision mediump float;" << endl;
  fs << "#define COLOR_PRECISION lowp" << endl;
  fs << "#define EDGE_PRECISION mediump" << endl;
  fs << "#else" << endl;
  fs << "#define COLOR_PRECISION" << endl;
  fs << "#define EDGE_PRECISION" << endl;
  fs << "#endif" << endl;
  if (aConfig.mFeatures & ENABLE_RENDER_COLOR) {
    fs << "uniform COLOR_PRECISION vec4 uRenderColor;" << endl;
  } else {
    // for tiling, texcoord can be greater than the lowfp range
    fs << "varying vec2 vTexCoord;" << endl;
    if (aConfig.mFeatures & ENABLE_BLUR) {
      fs << "uniform bool uBlurAlpha;" << endl;
      fs << "uniform vec2 uBlurRadius;" << endl;
      fs << "uniform vec2 uBlurOffset;" << endl;
      fs << "uniform float uBlurGaussianKernel[" << GAUSSIAN_KERNEL_HALF_WIDTH << "];" << endl;
    }
    if (aConfig.mFeatures & ENABLE_COLOR_MATRIX) {
      fs << "uniform mat4 uColorMatrix;" << endl;
      fs << "uniform vec4 uColorMatrixVector;" << endl;
    }
    if (aConfig.mFeatures & ENABLE_OPACITY) {
      fs << "uniform COLOR_PRECISION float uLayerOpacity;" << endl;
    }
  }
  if (BlendOpIsMixBlendMode(blendOp)) {
    fs << "varying vec2 vBackdropCoord;" << endl;
  }

  const char *sampler2D = "sampler2D";
  const char *texture2D = "texture2D";

  if (aConfig.mFeatures & ENABLE_TEXTURE_RECT) {
    fs << "uniform vec2 uTexCoordMultiplier;" << endl;
    if (aConfig.mFeatures & ENABLE_TEXTURE_YCBCR ||
        aConfig.mFeatures & ENABLE_TEXTURE_NV12) {
      fs << "uniform vec2 uCbCrTexCoordMultiplier;" << endl;
    }
    sampler2D = "sampler2DRect";
    texture2D = "texture2DRect";
  }

  if (aConfig.mFeatures & ENABLE_TEXTURE_EXTERNAL) {
    sampler2D = "samplerExternalOES";
  }

  if (aConfig.mFeatures & ENABLE_TEXTURE_YCBCR) {
    fs << "uniform sampler2D uYTexture;" << endl;
    fs << "uniform sampler2D uCbTexture;" << endl;
    fs << "uniform sampler2D uCrTexture;" << endl;
    fs << "uniform mat3 uYuvColorMatrix;" << endl;
  } else if (aConfig.mFeatures & ENABLE_TEXTURE_NV12) {
    fs << "uniform " << sampler2D << " uYTexture;" << endl;
    fs << "uniform " << sampler2D << " uCbTexture;" << endl;
  } else if (aConfig.mFeatures & ENABLE_TEXTURE_COMPONENT_ALPHA) {
    fs << "uniform " << sampler2D << " uBlackTexture;" << endl;
    fs << "uniform " << sampler2D << " uWhiteTexture;" << endl;
    fs << "uniform bool uTexturePass2;" << endl;
  } else {
    fs << "uniform " << sampler2D << " uTexture;" << endl;
  }

  if (BlendOpIsMixBlendMode(blendOp)) {
    // Component alpha should be flattened away inside blend containers.
    MOZ_ASSERT(!(aConfig.mFeatures & ENABLE_TEXTURE_COMPONENT_ALPHA));

    fs << "uniform sampler2D uBackdropTexture;" << endl;
  }

  if (aConfig.mFeatures & ENABLE_MASK) {
    fs << "varying vec3 vMaskCoord;" << endl;
    fs << "uniform sampler2D uMaskTexture;" << endl;
  }

  if (aConfig.mFeatures & ENABLE_DEAA) {
    fs << "uniform EDGE_PRECISION vec3 uSSEdges[4];" << endl;
  }

  if (BlendOpIsMixBlendMode(blendOp)) {
    BuildMixBlender(aConfig, fs);
  }

  if (!(aConfig.mFeatures & ENABLE_RENDER_COLOR)) {
    fs << "vec4 sample(vec2 coord) {" << endl;
    fs << "  vec4 color;" << endl;
    if (aConfig.mFeatures & ENABLE_TEXTURE_YCBCR ||
        aConfig.mFeatures & ENABLE_TEXTURE_NV12) {
      if (aConfig.mFeatures & ENABLE_TEXTURE_YCBCR) {
        if (aConfig.mFeatures & ENABLE_TEXTURE_RECT) {
          fs << "  COLOR_PRECISION float y = texture2D(uYTexture, coord * uTexCoordMultiplier).r;" << endl;
          fs << "  COLOR_PRECISION float cb = texture2D(uCbTexture, coord * uCbCrTexCoordMultiplier).r;" << endl;
          fs << "  COLOR_PRECISION float cr = texture2D(uCrTexture, coord * uCbCrTexCoordMultiplier).r;" << endl;
        } else {
          fs << "  COLOR_PRECISION float y = texture2D(uYTexture, coord).r;" << endl;
          fs << "  COLOR_PRECISION float cb = texture2D(uCbTexture, coord).r;" << endl;
          fs << "  COLOR_PRECISION float cr = texture2D(uCrTexture, coord).r;" << endl;
        }
      } else {
        if (aConfig.mFeatures & ENABLE_TEXTURE_RECT) {
          fs << "  COLOR_PRECISION float y = " << texture2D << "(uYTexture, coord * uTexCoordMultiplier).r;" << endl;
          fs << "  COLOR_PRECISION float cb = " << texture2D << "(uCbTexture, coord * uCbCrTexCoordMultiplier).r;" << endl;
          fs << "  COLOR_PRECISION float cr = " << texture2D << "(uCbTexture, coord * uCbCrTexCoordMultiplier).a;" << endl;
        } else {
          fs << "  COLOR_PRECISION float y = " << texture2D << "(uYTexture, coord).r;" << endl;
          fs << "  COLOR_PRECISION float cb = " << texture2D << "(uCbTexture, coord).r;" << endl;
          fs << "  COLOR_PRECISION float cr = " << texture2D << "(uCbTexture, coord).a;" << endl;
        }
      }

      fs << "  y = y - 0.06275;" << endl;
      fs << "  cb = cb - 0.50196;" << endl;
      fs << "  cr = cr - 0.50196;" << endl;
      fs << "  vec3 yuv = vec3(y, cb, cr);" << endl;
      fs << "  color.rgb = uYuvColorMatrix * yuv;" << endl;
      fs << "  color.a = 1.0;" << endl;
    } else if (aConfig.mFeatures & ENABLE_TEXTURE_COMPONENT_ALPHA) {
      if (aConfig.mFeatures & ENABLE_TEXTURE_RECT) {
        fs << "  COLOR_PRECISION vec3 onBlack = " << texture2D << "(uBlackTexture, coord * uTexCoordMultiplier).rgb;" << endl;
        fs << "  COLOR_PRECISION vec3 onWhite = " << texture2D << "(uWhiteTexture, coord * uTexCoordMultiplier).rgb;" << endl;
      } else {
        fs << "  COLOR_PRECISION vec3 onBlack = " << texture2D << "(uBlackTexture, coord).rgb;" << endl;
        fs << "  COLOR_PRECISION vec3 onWhite = " << texture2D << "(uWhiteTexture, coord).rgb;" << endl;
      }
      fs << "  COLOR_PRECISION vec4 alphas = (1.0 - onWhite + onBlack).rgbg;" << endl;
      fs << "  if (uTexturePass2)" << endl;
      fs << "    color = vec4(onBlack, alphas.a);" << endl;
      fs << "  else" << endl;
      fs << "    color = alphas;" << endl;
    } else {
      if (aConfig.mFeatures & ENABLE_TEXTURE_RECT) {
        fs << "  color = " << texture2D << "(uTexture, coord * uTexCoordMultiplier);" << endl;
      } else {
        fs << "  color = " << texture2D << "(uTexture, coord);" << endl;
      }
    }
    if (aConfig.mFeatures & ENABLE_TEXTURE_RB_SWAP) {
      fs << "  color = color.bgra;" << endl;
    }
    if (aConfig.mFeatures & ENABLE_TEXTURE_NO_ALPHA) {
      fs << "  color = vec4(color.rgb, 1.0);" << endl;
    }
    fs << "  return color;" << endl;
    fs << "}" << endl;
    if (aConfig.mFeatures & ENABLE_BLUR) {
      fs << "vec4 sampleAtRadius(vec2 coord, float radius) {" << endl;
      fs << "  coord += uBlurOffset;" << endl;
      fs << "  coord += radius * uBlurRadius;" << endl;
      fs << "  if (coord.x < 0. || coord.y < 0. || coord.x > 1. || coord.y > 1.)" << endl;
      fs << "    return vec4(0, 0, 0, 0);" << endl;
      fs << "  return sample(coord);" << endl;
      fs << "}" << endl;
      fs << "vec4 blur(vec4 color, vec2 coord) {" << endl;
      fs << "  vec4 total = color * uBlurGaussianKernel[0];" << endl;
      fs << "  for (int i = 1; i < " << GAUSSIAN_KERNEL_HALF_WIDTH << "; ++i) {" << endl;
      fs << "    float r = float(i) * " << GAUSSIAN_KERNEL_STEP << ";" << endl;
      fs << "    float k = uBlurGaussianKernel[i];" << endl;
      fs << "    total += sampleAtRadius(coord, r) * k;" << endl;
      fs << "    total += sampleAtRadius(coord, -r) * k;" << endl;
      fs << "  }" << endl;
      fs << "  if (uBlurAlpha) {" << endl;
      fs << "    color *= total.a;" << endl;
      fs << "  } else {" << endl;
      fs << "    color = total;" << endl;
      fs << "  }" << endl;
      fs << "  return color;" << endl;
      fs << "}" << endl;
    }
  }
  fs << "void main() {" << endl;
  if (aConfig.mFeatures & ENABLE_RENDER_COLOR) {
    fs << "  vec4 color = uRenderColor;" << endl;
  } else {
    fs << "  vec4 color = sample(vTexCoord);" << endl;
    if (aConfig.mFeatures & ENABLE_BLUR) {
      fs << "  color = blur(color, vTexCoord);" << endl;
    }
    if (aConfig.mFeatures & ENABLE_COLOR_MATRIX) {
      fs << "  color = uColorMatrix * vec4(color.rgb / color.a, color.a) + uColorMatrixVector;" << endl;
      fs << "  color.rgb *= color.a;" << endl;
    }
    if (aConfig.mFeatures & ENABLE_OPACITY) {
      fs << "  color *= uLayerOpacity;" << endl;
    }
  }
  if (aConfig.mFeatures & ENABLE_DEAA) {
    // Calculate the sub-pixel coverage of the pixel and modulate its opacity
    // by that amount to perform DEAA.
    fs << "  vec3 ssPos = vec3(gl_FragCoord.xy, 1.0);" << endl;
    fs << "  float deaaCoverage = clamp(dot(uSSEdges[0], ssPos), 0.0, 1.0);" << endl;
    fs << "  deaaCoverage *= clamp(dot(uSSEdges[1], ssPos), 0.0, 1.0);" << endl;
    fs << "  deaaCoverage *= clamp(dot(uSSEdges[2], ssPos), 0.0, 1.0);" << endl;
    fs << "  deaaCoverage *= clamp(dot(uSSEdges[3], ssPos), 0.0, 1.0);" << endl;
    fs << "  color *= deaaCoverage;" << endl;
  }
  if (BlendOpIsMixBlendMode(blendOp)) {
    fs << "  vec4 backdrop = texture2D(uBackdropTexture, vBackdropCoord);" << endl;
    fs << "  color = mixAndBlend(backdrop, color);" << endl;
  }
  if (aConfig.mFeatures & ENABLE_MASK) {
    fs << "  vec2 maskCoords = vMaskCoord.xy / vMaskCoord.z;" << endl;
    fs << "  COLOR_PRECISION float mask = texture2D(uMaskTexture, maskCoords).r;" << endl;
    fs << "  color *= mask;" << endl;
  } else {
    fs << "  COLOR_PRECISION float mask = 1.0;" << endl;
    fs << "  color *= mask;" << endl;
  }
  fs << "  gl_FragColor = color;" << endl;
  fs << "}" << endl;

  result.mVertexShaderString = vs.str();
  result.mFragmentShaderString = fs.str();

  if (aConfig.mFeatures & ENABLE_RENDER_COLOR) {
    result.mTextureCount = 0;
  } else {
    if (aConfig.mFeatures & ENABLE_TEXTURE_YCBCR) {
      result.mTextureCount = 3;
    } else if (aConfig.mFeatures & ENABLE_TEXTURE_NV12) {
      result.mTextureCount = 2;
    } else if (aConfig.mFeatures & ENABLE_TEXTURE_COMPONENT_ALPHA) {
      result.mTextureCount = 2;
    } else {
      result.mTextureCount = 1;
    }
  }
  if (aConfig.mFeatures & ENABLE_MASK) {
    result.mTextureCount = 1;
  }
  if (BlendOpIsMixBlendMode(blendOp)) {
    result.mTextureCount += 1;
  }

  return result;
}

void
ProgramProfileOGL::BuildMixBlender(const ShaderConfigOGL& aConfig, std::ostringstream& fs)
{
  // From the "Compositing and Blending Level 1" spec.
  // Generate helper functions first.
  switch (aConfig.mCompositionOp) {
  case gfx::CompositionOp::OP_OVERLAY:
  case gfx::CompositionOp::OP_HARD_LIGHT:
    // Note: we substitute (2*src-1) into the screen formula below.
    fs << "float hardlight(float dest, float src) {" << endl;
    fs << "  if (src <= 0.5) {" << endl;
    fs << "    return dest * (2.0 * src);" << endl;
    fs << "  } else {" << endl;
    fs << "    return 2.0*dest + 2.0*src - 1.0 - 2.0*dest*src;" << endl;
    fs << "  }" << endl;
    fs << "}" << endl;
    break;
  case gfx::CompositionOp::OP_COLOR_DODGE:
    fs << "float dodge(float dest, float src) {" << endl;
    fs << "  if (dest == 0.0) {" << endl;
    fs << "    return 0.0;" << endl;
    fs << "  } else if (src == 1.0) {" << endl;
    fs << "    return 1.0;" << endl;
    fs << "  } else {" << endl;
    fs << "    return min(1.0, dest / (1.0 - src));" << endl;
    fs << "  }" << endl;
    fs << "}" << endl;
    break;
  case gfx::CompositionOp::OP_COLOR_BURN:
    fs << "float burn(float dest, float src) {" << endl;
    fs << "  if (dest == 1.0) {" << endl;
    fs << "    return 1.0;" << endl;
    fs << "  } else if (src == 0.0) {" << endl;
    fs << "    return 0.0;" << endl;
    fs << "  } else {" << endl;
    fs << "    return 1.0 - min(1.0, (1.0 - dest) / src);" << endl;
    fs << "  }" << endl;
    fs << "}" << endl;
    break;
  case gfx::CompositionOp::OP_SOFT_LIGHT:
    fs << "float darken(float dest) {" << endl;
    fs << "  if (dest <= 0.25) {" << endl;
    fs << "    return ((16.0 * dest - 12.0) * dest + 4.0) * dest;" << endl;
    fs << "  } else {" << endl;
    fs << "    return sqrt(dest);" << endl;
    fs << "  }" << endl;
    fs << "}" << endl;
    fs << "float softlight(float dest, float src) {" << endl;
    fs << "  if (src <= 0.5) {" << endl;
    fs << "    return dest - (1.0 - 2.0 * src) * dest * (1.0 - dest);" << endl;
    fs << "  } else {" << endl;
    fs << "    return dest + (2.0 * src - 1.0) * (darken(dest) - dest);" << endl;
    fs << "  }" << endl;
    fs << "}" << endl;
    break;
  case gfx::CompositionOp::OP_HUE:
  case gfx::CompositionOp::OP_SATURATION:
  case gfx::CompositionOp::OP_COLOR:
  case gfx::CompositionOp::OP_LUMINOSITY:
    fs << "float Lum(vec3 c) {" << endl;
    fs << "  return dot(vec3(0.3, 0.59, 0.11), c);" << endl;
    fs << "}" << endl;
    fs << "vec3 ClipColor(vec3 c) {" << endl;
    fs << "  float L = Lum(c);" << endl;
    fs << "  float n = min(min(c.r, c.g), c.b);" << endl;
    fs << "  float x = max(max(c.r, c.g), c.b);" << endl;
    fs << "  if (n < 0.0) {" << endl;
    fs << "    c = L + (((c - L) * L) / (L - n));" << endl;
    fs << "  }" << endl;
    fs << "  if (x > 1.0) {" << endl;
    fs << "    c = L + (((c - L) * (1.0 - L)) / (x - L));" << endl;
    fs << "  }" << endl;
    fs << "  return c;" << endl;
    fs << "}" << endl;
    fs << "vec3 SetLum(vec3 c, float L) {" << endl;
    fs << "  float d = L - Lum(c);" << endl;
    fs << "  return ClipColor(vec3(" << endl;
    fs << "    c.r + d," << endl;
    fs << "    c.g + d," << endl;
    fs << "    c.b + d));" << endl;
    fs << "}" << endl;
    fs << "float Sat(vec3 c) {" << endl;
    fs << "  return max(max(c.r, c.g), c.b) - min(min(c.r, c.g), c.b);" << endl;
    fs << "}" << endl;

    // To use this helper, re-arrange rgb such that r=min, g=mid, and b=max.
    fs << "vec3 SetSatInner(vec3 c, float s) {" << endl;
    fs << "  if (c.b > c.r) {" << endl;
    fs << "    c.g = (((c.g - c.r) * s) / (c.b - c.r));" << endl;
    fs << "    c.b = s;" << endl;
    fs << "  } else {" << endl;
    fs << "    c.gb = vec2(0.0, 0.0);" << endl;
    fs << "  }" << endl;
    fs << "  return vec3(0.0, c.gb);" << endl;
    fs << "}" << endl;

    fs << "vec3 SetSat(vec3 c, float s) {" << endl;
    fs << "  if (c.r <= c.g) {" << endl;
    fs << "    if (c.g <= c.b) {" << endl;
    fs << "      c.rgb = SetSatInner(c.rgb, s);" << endl;
    fs << "    } else if (c.r <= c.b) {" << endl;
    fs << "      c.rbg = SetSatInner(c.rbg, s);" << endl;
    fs << "    } else {" << endl;
    fs << "      c.brg = SetSatInner(c.brg, s);" << endl;
    fs << "    }" << endl;
    fs << "  } else if (c.r <= c.b) {" << endl;
    fs << "    c.grb = SetSatInner(c.grb, s);" << endl;
    fs << "  } else if (c.g <= c.b) {" << endl;
    fs << "    c.gbr = SetSatInner(c.gbr, s);" << endl;
    fs << "  } else {" << endl;
    fs << "    c.bgr = SetSatInner(c.bgr, s);" << endl;
    fs << "  }" << endl;
    fs << "  return c;" << endl;
    fs << "}" << endl;
    break;
  default:
    break;
  }

  // Generate the main blending helper.
  fs << "vec3 blend(vec3 dest, vec3 src) {" << endl;
  switch (aConfig.mCompositionOp) {
  case gfx::CompositionOp::OP_MULTIPLY:
    fs << "  return dest * src;" << endl;
    break;
  case gfx::CompositionOp::OP_SCREEN:
    fs << "  return dest + src - (dest * src);" << endl;
    break;
  case gfx::CompositionOp::OP_OVERLAY:
    fs << "  return vec3(" << endl;
    fs << "    hardlight(src.r, dest.r)," << endl;
    fs << "    hardlight(src.g, dest.g)," << endl;
    fs << "    hardlight(src.b, dest.b));" << endl;
    break;
  case gfx::CompositionOp::OP_DARKEN:
    fs << "  return min(dest, src);" << endl;
    break;
  case gfx::CompositionOp::OP_LIGHTEN:
    fs << "  return max(dest, src);" << endl;
    break;
  case gfx::CompositionOp::OP_COLOR_DODGE:
    fs << "  return vec3(" << endl;
    fs << "    dodge(dest.r, src.r)," << endl;
    fs << "    dodge(dest.g, src.g)," << endl;
    fs << "    dodge(dest.b, src.b));" << endl;
    break;
  case gfx::CompositionOp::OP_COLOR_BURN:
    fs << "  return vec3(" << endl;
    fs << "    burn(dest.r, src.r)," << endl;
    fs << "    burn(dest.g, src.g)," << endl;
    fs << "    burn(dest.b, src.b));" << endl;
    break;
  case gfx::CompositionOp::OP_HARD_LIGHT:
    fs << "  return vec3(" << endl;
    fs << "    hardlight(dest.r, src.r)," << endl;
    fs << "    hardlight(dest.g, src.g)," << endl;
    fs << "    hardlight(dest.b, src.b));" << endl;
    break;
  case gfx::CompositionOp::OP_SOFT_LIGHT:
    fs << "  return vec3(" << endl;
    fs << "    softlight(dest.r, src.r)," << endl;
    fs << "    softlight(dest.g, src.g)," << endl;
    fs << "    softlight(dest.b, src.b));" << endl;
    break;
  case gfx::CompositionOp::OP_DIFFERENCE:
    fs << "  return abs(dest - src);" << endl;
    break;
  case gfx::CompositionOp::OP_EXCLUSION:
    fs << "  return dest + src - 2.0*dest*src;" << endl;
    break;
  case gfx::CompositionOp::OP_HUE:
    fs << "  return SetLum(SetSat(src, Sat(dest)), Lum(dest));" << endl;
    break;
  case gfx::CompositionOp::OP_SATURATION:
    fs << "  return SetLum(SetSat(dest, Sat(src)), Lum(dest));" << endl;
    break;
  case gfx::CompositionOp::OP_COLOR:
    fs << "  return SetLum(src, Lum(dest));" << endl;
    break;
  case gfx::CompositionOp::OP_LUMINOSITY:
    fs << "  return SetLum(dest, Lum(src));" << endl;
    break;
  default:
    MOZ_ASSERT_UNREACHABLE("unknown blend mode");
  }
  fs << "}" << endl;

  // Generate the mix-blend function the fragment shader will call.
  fs << "vec4 mixAndBlend(vec4 backdrop, vec4 color) {" << endl;

  // Shortcut when the backdrop or source alpha is 0, otherwise we may leak
  // Infinity into the blend function and return incorrect results.
  fs << "  if (backdrop.a == 0.0) {" << endl;
  fs << "    return color;" << endl;
  fs << "  }" << endl;
  fs << "  if (color.a == 0.0) {" << endl;
  fs << "    return vec4(0.0, 0.0, 0.0, 0.0);" << endl;
  fs << "  }" << endl;

  // The spec assumes there is no premultiplied alpha. The backdrop is always
  // premultiplied, so undo the premultiply. If the source is premultiplied we
  // must fix that as well.
  fs << "  backdrop.rgb /= backdrop.a;" << endl;
  if (!(aConfig.mFeatures & ENABLE_NO_PREMUL_ALPHA)) {
    fs << "  color.rgb /= color.a;" << endl;
  }
  fs << "  vec3 blended = blend(backdrop.rgb, color.rgb);" << endl;
  fs << "  color.rgb = (1.0 - backdrop.a) * color.rgb + backdrop.a * blended.rgb;" << endl;
  fs << "  color.rgb *= color.a;" << endl;
  fs << "  return color;" << endl;
  fs << "}" << endl;
}

ShaderProgramOGL::ShaderProgramOGL(GLContext* aGL, const ProgramProfileOGL& aProfile)
  : mGL(aGL)
  , mProgram(0)
  , mProfile(aProfile)
  , mProgramState(STATE_NEW)
{
}

ShaderProgramOGL::~ShaderProgramOGL()
{
  if (mProgram <= 0) {
    return;
  }

  RefPtr<GLContext> ctx = mGL->GetSharedContext();
  if (!ctx) {
    ctx = mGL;
  }
  ctx->MakeCurrent();
  ctx->fDeleteProgram(mProgram);
}

bool
ShaderProgramOGL::Initialize()
{
  NS_ASSERTION(mProgramState == STATE_NEW, "Shader program has already been initialised");

  ostringstream vs, fs;
  for (uint32_t i = 0; i < mProfile.mDefines.Length(); ++i) {
    vs << mProfile.mDefines[i] << endl;
    fs << mProfile.mDefines[i] << endl;
  }
  vs << mProfile.mVertexShaderString << endl;
  fs << mProfile.mFragmentShaderString << endl;

  if (!CreateProgram(vs.str().c_str(), fs.str().c_str())) {
    mProgramState = STATE_ERROR;
    return false;
  }

  mProgramState = STATE_OK;

  for (uint32_t i = 0; i < KnownUniform::KnownUniformCount; ++i) {
    mProfile.mUniforms[i].mLocation =
      mGL->fGetUniformLocation(mProgram, mProfile.mUniforms[i].mNameString);
  }

  return true;
}

GLint
ShaderProgramOGL::CreateShader(GLenum aShaderType, const char *aShaderSource)
{
  GLint success, len = 0;

  GLint sh = mGL->fCreateShader(aShaderType);
  mGL->fShaderSource(sh, 1, (const GLchar**)&aShaderSource, nullptr);
  mGL->fCompileShader(sh);
  mGL->fGetShaderiv(sh, LOCAL_GL_COMPILE_STATUS, &success);
  mGL->fGetShaderiv(sh, LOCAL_GL_INFO_LOG_LENGTH, (GLint*) &len);
  /* Even if compiling is successful, there may still be warnings.  Print them
   * in a debug build.  The > 10 is to catch silly compilers that might put
   * some whitespace in the log but otherwise leave it empty.
   */
  if (!success
#ifdef DEBUG
      || (len > 10 && gfxEnv::DebugShaders())
#endif
      )
  {
    nsAutoCString log;
    log.SetCapacity(len);
    mGL->fGetShaderInfoLog(sh, len, (GLint*) &len, (char*) log.BeginWriting());
    log.SetLength(len);

    if (!success) {
      printf_stderr("=== SHADER COMPILATION FAILED ===\n");
    } else {
      printf_stderr("=== SHADER COMPILATION WARNINGS ===\n");
    }

      printf_stderr("=== Source:\n%s\n", aShaderSource);
      printf_stderr("=== Log:\n%s\n", log.get());
      printf_stderr("============\n");

    if (!success) {
      mGL->fDeleteShader(sh);
      return 0;
    }
  }

  return sh;
}

bool
ShaderProgramOGL::CreateProgram(const char *aVertexShaderString,
                                const char *aFragmentShaderString)
{
  GLuint vertexShader = CreateShader(LOCAL_GL_VERTEX_SHADER, aVertexShaderString);
  GLuint fragmentShader = CreateShader(LOCAL_GL_FRAGMENT_SHADER, aFragmentShaderString);

  if (!vertexShader || !fragmentShader)
    return false;

  GLint result = mGL->fCreateProgram();
  mGL->fAttachShader(result, vertexShader);
  mGL->fAttachShader(result, fragmentShader);

  for (Pair<nsCString, GLuint>& attribute : mProfile.mAttributes) {
    mGL->fBindAttribLocation(result, attribute.second(),
                             attribute.first().get());
  }

  mGL->fLinkProgram(result);

  GLint success, len;
  mGL->fGetProgramiv(result, LOCAL_GL_LINK_STATUS, &success);
  mGL->fGetProgramiv(result, LOCAL_GL_INFO_LOG_LENGTH, (GLint*) &len);
  /* Even if linking is successful, there may still be warnings.  Print them
   * in a debug build.  The > 10 is to catch silly compilers that might put
   * some whitespace in the log but otherwise leave it empty.
   */
  if (!success
#ifdef DEBUG
      || (len > 10 && gfxEnv::DebugShaders())
#endif
      )
  {
    nsAutoCString log;
    log.SetCapacity(len);
    mGL->fGetProgramInfoLog(result, len, (GLint*) &len, (char*) log.BeginWriting());
    log.SetLength(len);

    if (!success) {
      printf_stderr("=== PROGRAM LINKING FAILED ===\n");
    } else {
      printf_stderr("=== PROGRAM LINKING WARNINGS ===\n");
    }
    printf_stderr("=== Log:\n%s\n", log.get());
    printf_stderr("============\n");
  }

  // We can mark the shaders for deletion; they're attached to the program
  // and will remain attached.
  mGL->fDeleteShader(vertexShader);
  mGL->fDeleteShader(fragmentShader);

  if (!success) {
    mGL->fDeleteProgram(result);
    return false;
  }

  mProgram = result;
  return true;
}

GLuint
ShaderProgramOGL::GetProgram()
{
  if (mProgramState == STATE_NEW) {
    if (!Initialize()) {
      NS_WARNING("Shader could not be initialised");
    }
  }
  MOZ_ASSERT(HasInitialized(), "Attempting to get a program that's not been initialized!");
  return mProgram;
}

void
ShaderProgramOGL::SetBlurRadius(float aRX, float aRY)
{
  float f[] = {aRX, aRY};
  SetUniform(KnownUniform::BlurRadius, 2, f);

  float gaussianKernel[GAUSSIAN_KERNEL_HALF_WIDTH];
  float sum = 0.0f;
  for (int i = 0; i < GAUSSIAN_KERNEL_HALF_WIDTH; i++) {
    float x = i * GAUSSIAN_KERNEL_STEP;
    float sigma = 1.0f;
    gaussianKernel[i] = exp(-x * x / (2 * sigma * sigma)) / sqrt(2 * M_PI * sigma * sigma);
    sum += gaussianKernel[i] * (i == 0 ? 1 : 2);
  }
  for (int i = 0; i < GAUSSIAN_KERNEL_HALF_WIDTH; i++) {
    gaussianKernel[i] /= sum;
  }
  SetArrayUniform(KnownUniform::BlurGaussianKernel, GAUSSIAN_KERNEL_HALF_WIDTH, gaussianKernel);
}

void
ShaderProgramOGL::SetYUVColorSpace(YUVColorSpace aYUVColorSpace)
{
  float* yuvToRgb = gfxUtils::Get3x3YuvColorMatrix(aYUVColorSpace);
  SetMatrix3fvUniform(KnownUniform::YuvColorMatrix, yuvToRgb);
}

} // namespace layers
} // namespace mozilla
