cc: Use highp precision for texture coords if available and needed

cc/output/shader.h

 // Copyright 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CC_OUTPUT_SHADER_H_
 #define CC_OUTPUT_SHADER_H_
 
 #include <string>
 #include "third_party/skia/include/core/SkColorPriv.h"
 
+namespace gfx {
+class Point;
+}
+
 namespace WebKit {
 class WebGraphicsContext3D;
 }
 
 namespace cc {
 
+enum TexCoordPrecision {
+  TexCoordPrecisionNA,
+  TexCoordPrecisionMedium,
+  TexCoordPrecisionHigh,
+};
+
+int TexCoordHighpThreshold(WebKit::WebGraphicsContext3D* context);
+
+TexCoordPrecision TexCoordPrecisionRequired(
+    WebKit::WebGraphicsContext3D* context,
+    const gfx::Point &max_coordinate);
+
 class VertexShaderPosTex {
 public:
     VertexShaderPosTex();
 
     void init(WebKit::WebGraphicsContext3D*, unsigned program, bool usingBindUniform, int* baseUniformIndex);
     std::string getShaderString() const;
 
     int matrixLocation() const { return m_matrixLocation; }
 
 private:
@@ skipping 129 matching lines @@
     int edgeLocation() const { return -1; }
     int fragmentTexTransformLocation() const { return -1; }
     int samplerLocation() const { return m_samplerLocation; }
 
 private:
     int m_samplerLocation;
 };
 
 class FragmentShaderRGBATexVaryingAlpha : public FragmentTexOpaqueBinding {
 public:
-    std::string getShaderString() const;
+    std::string getShaderString(TexCoordPrecision precision) const;
 };
 
 class FragmentShaderRGBATexAlpha : public FragmentTexAlphaBinding {
 public:
-    std::string getShaderString() const;
+    std::string getShaderString(TexCoordPrecision precision) const;
 };
 
 class FragmentShaderRGBATexRectVaryingAlpha : public FragmentTexAlphaBinding {
 public:
-    std::string getShaderString() const;
+    std::string getShaderString(TexCoordPrecision precision) const;
 };
 
 class FragmentShaderRGBATexOpaque : public FragmentTexOpaqueBinding {
 public:
-    std::string getShaderString() const;
+    std::string getShaderString(TexCoordPrecision precision) const;
 };
 
 class FragmentShaderRGBATex : public FragmentTexOpaqueBinding {
 public:
-    std::string getShaderString() const;
+    std::string getShaderString(TexCoordPrecision precision) const;
 };
 
 // Swizzles the red and blue component of sampled texel with alpha.
 class FragmentShaderRGBATexSwizzleAlpha : public FragmentTexAlphaBinding {
 public:
-    std::string getShaderString() const;
+    std::string getShaderString(TexCoordPrecision precision) const;
 };
 
 // Swizzles the red and blue component of sampled texel without alpha.
 class FragmentShaderRGBATexSwizzleOpaque : public FragmentTexOpaqueBinding {
 public:
-    std::string getShaderString() const;
+    std::string getShaderString(TexCoordPrecision precision) const;
 };
 
 // Fragment shader for external textures.
 class FragmentShaderOESImageExternal : public FragmentTexAlphaBinding {
 public:
-    std::string getShaderString() const;
+    std::string getShaderString(TexCoordPrecision precision) const;
     bool init(WebKit::WebGraphicsContext3D*, unsigned program, bool usingBindUniform, int* baseUniformIndex);
 private:
     int m_samplerLocation;
 };
 
 class FragmentShaderRGBATexAlphaAA {
 public:
     FragmentShaderRGBATexAlphaAA();
 
     void init(WebKit::WebGraphicsContext3D*, unsigned program, bool usingBindUniform, int* baseUniformIndex);
-    std::string getShaderString() const;
+    std::string getShaderString(TexCoordPrecision precision) const;
 
     int alphaLocation() const { return m_alphaLocation; }
     int samplerLocation() const { return m_samplerLocation; }
     int edgeLocation() const { return m_edgeLocation; }
 
 private:
     int m_samplerLocation;
     int m_alphaLocation;
     int m_edgeLocation;
 };
@@ skipping 10 matching lines @@
 
 private:
     int m_samplerLocation;
     int m_alphaLocation;
     int m_fragmentTexTransformLocation;
     int m_edgeLocation;
 };
 
 class FragmentShaderRGBATexClampAlphaAA : public FragmentTexClampAlphaAABinding {
 public:
-    std::string getShaderString() const;
+    std::string getShaderString(TexCoordPrecision precision) const;
 };
 
 // Swizzles the red and blue component of sampled texel.
 class FragmentShaderRGBATexClampSwizzleAlphaAA : public FragmentTexClampAlphaAABinding {
 public:
-    std::string getShaderString() const;
+    std::string getShaderString(TexCoordPrecision precision) const;
 };
 
 class FragmentShaderRGBATexAlphaMask {
 public:
     FragmentShaderRGBATexAlphaMask();
-    std::string getShaderString() const;
+    std::string getShaderString(TexCoordPrecision precision) const;
 
     void init(WebKit::WebGraphicsContext3D*, unsigned program, bool usingBindUniform, int* baseUniformIndex);
     int alphaLocation() const { return m_alphaLocation; }
     int samplerLocation() const { return m_samplerLocation; }
     int maskSamplerLocation() const { return m_maskSamplerLocation; }
     int maskTexCoordScaleLocation() const { return m_maskTexCoordScaleLocation; }
     int maskTexCoordOffsetLocation() const { return m_maskTexCoordOffsetLocation; }
 
 private:
     int m_samplerLocation;
     int m_maskSamplerLocation;
     int m_alphaLocation;
     int m_maskTexCoordScaleLocation;
     int m_maskTexCoordOffsetLocation;
 };
 
 class FragmentShaderRGBATexAlphaMaskAA {
 public:
     FragmentShaderRGBATexAlphaMaskAA();
-    std::string getShaderString() const;
+    std::string getShaderString(TexCoordPrecision precision) const;
 
     void init(WebKit::WebGraphicsContext3D*, unsigned program, bool usingBindUniform, int* baseUniformIndex);
     int alphaLocation() const { return m_alphaLocation; }
     int samplerLocation() const { return m_samplerLocation; }
     int maskSamplerLocation() const { return m_maskSamplerLocation; }
     int edgeLocation() const { return m_edgeLocation; }
     int maskTexCoordScaleLocation() const { return m_maskTexCoordScaleLocation; }
     int maskTexCoordOffsetLocation() const { return m_maskTexCoordOffsetLocation; }
 
 private:
     int m_samplerLocation;
     int m_maskSamplerLocation;
     int m_alphaLocation;
     int m_edgeLocation;
     int m_maskTexCoordScaleLocation;
     int m_maskTexCoordOffsetLocation;
 };
 
 class FragmentShaderYUVVideo {
 public:
     FragmentShaderYUVVideo();
-    std::string getShaderString() const;
+    std::string getShaderString(TexCoordPrecision precision) const;
 
     void init(WebKit::WebGraphicsContext3D*, unsigned program, bool usingBindUniform, int* baseUniformIndex);
 
     int yTextureLocation() const { return m_yTextureLocation; }
     int uTextureLocation() const { return m_uTextureLocation; }
     int vTextureLocation() const { return m_vTextureLocation; }
     int alphaLocation() const { return m_alphaLocation; }
     int yuvMatrixLocation() const { return m_yuvMatrixLocation; }
     int yuvAdjLocation() const { return m_yuvAdjLocation; }
 
 private:
     int m_yTextureLocation;
     int m_uTextureLocation;
     int m_vTextureLocation;
     int m_alphaLocation;
     int m_yuvMatrixLocation;
     int m_yuvAdjLocation;
 };
 
 class FragmentShaderColor {
 public:
     FragmentShaderColor();
-    std::string getShaderString() const;
+    std::string getShaderString(TexCoordPrecision precision) const;
 
     void init(WebKit::WebGraphicsContext3D*, unsigned program, bool usingBindUniform, int* baseUniformIndex);
     int edgeLocation() const { return -1; }
     int colorLocation() const { return m_colorLocation; }
 
 private:
     int m_colorLocation;
 };
 
 class FragmentShaderColorAA {
 public:
     FragmentShaderColorAA();
-    std::string getShaderString() const;
+    std::string getShaderString(TexCoordPrecision precision) const;
 
     void init(WebKit::WebGraphicsContext3D*, unsigned program, bool usingBindUniform, int* baseUniformIndex);
     int edgeLocation() const { return m_edgeLocation; }
     int colorLocation() const { return m_colorLocation; }
 
 private:
     int m_edgeLocation;
     int m_colorLocation;
 };
 
 class FragmentShaderCheckerboard {
 public:
     FragmentShaderCheckerboard();
-    std::string getShaderString() const;
+    std::string getShaderString(TexCoordPrecision precision) const;
 
     void init(WebKit::WebGraphicsContext3D*, unsigned program, bool usingBindUniform, int* baseUniformIndex);
     int alphaLocation() const { return m_alphaLocation; }
     int texTransformLocation() const { return m_texTransformLocation; }
     int frequencyLocation() const { return m_frequencyLocation; }
     int colorLocation() const { return m_colorLocation; }
 private:
     int m_alphaLocation;
     int m_texTransformLocation;
     int m_frequencyLocation;
     int m_colorLocation;
 };
 
 } // namespace cc
 
 #endif  // CC_OUTPUT_SHADER_H_