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 using_bind_uniform,
             int* base_uniform_index);
   std::string GetShaderString() const;
 
@@ skipping 161 matching lines @@
   int edge_location() const { return -1; }
   int fragment_tex_transform_location() const { return -1; }
   int sampler_location() const { return sampler_location_; }
 
  private:
   int sampler_location_;
 };
 
 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 using_bind_uniform,
             int* base_uniform_index);
  private:
   int sampler_location_;
 };
 
 class FragmentShaderRGBATexAlphaAA {
  public:
   FragmentShaderRGBATexAlphaAA();
 
   void Init(WebKit::WebGraphicsContext3D*,
             unsigned program,
             bool using_bind_uniform,
             int* base_uniform_index);
-  std::string GetShaderString() const;
+  std::string GetShaderString(TexCoordPrecision precision) const;
 
   int alpha_location() const { return alpha_location_; }
   int sampler_location() const { return sampler_location_; }
   int edge_location() const { return edge_location_; }
 
  private:
   int sampler_location_;
   int alpha_location_;
   int edge_location_;
 };
@@ skipping 16 matching lines @@
  private:
   int sampler_location_;
   int alpha_location_;
   int fragment_tex_transform_location_;
   int edge_location_;
 };
 
 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 using_bind_uniform,
             int* base_uniform_index);
   int alpha_location() const { return alpha_location_; }
   int sampler_location() const { return sampler_location_; }
   int mask_sampler_location() const { return mask_sampler_location_; }
   int mask_tex_coord_scale_location() const {
     return mask_tex_coord_scale_location_;
   }
   int mask_tex_coord_offset_location() const {
     return mask_tex_coord_offset_location_;
   }
 
  private:
   int sampler_location_;
   int mask_sampler_location_;
   int alpha_location_;
   int mask_tex_coord_scale_location_;
   int mask_tex_coord_offset_location_;
 };
 
 class FragmentShaderRGBATexAlphaMaskAA {
  public:
   FragmentShaderRGBATexAlphaMaskAA();
-  std::string GetShaderString() const;
+  std::string GetShaderString(TexCoordPrecision precision) const;
 
   void Init(WebKit::WebGraphicsContext3D*,
             unsigned program,
             bool using_bind_uniform,
             int* base_uniform_index);
   int alpha_location() const { return alpha_location_; }
   int sampler_location() const { return sampler_location_; }
   int mask_sampler_location() const { return mask_sampler_location_; }
   int edge_location() const { return edge_location_; }
   int mask_tex_coord_scale_location() const {
     return mask_tex_coord_scale_location_;
   }
   int mask_tex_coord_offset_location() const {
     return mask_tex_coord_offset_location_;
   }
 
  private:
   int sampler_location_;
   int mask_sampler_location_;
   int alpha_location_;
   int edge_location_;
   int mask_tex_coord_scale_location_;
   int mask_tex_coord_offset_location_;
 };
 
 class FragmentShaderYUVVideo {
  public:
   FragmentShaderYUVVideo();
-  std::string GetShaderString() const;
+  std::string GetShaderString(TexCoordPrecision precision) const;
 
   void Init(WebKit::WebGraphicsContext3D*,
             unsigned program,
             bool using_bind_uniform,
             int* base_uniform_index);
   int y_texture_location() const { return y_texture_location_; }
   int u_texture_location() const { return u_texture_location_; }
   int v_texture_location() const { return v_texture_location_; }
   int alpha_location() const { return alpha_location_; }
   int yuv_matrix_location() const { return yuv_matrix_location_; }
   int yuv_adj_location() const { return yuv_adj_location_; }
 
  private:
   int y_texture_location_;
   int u_texture_location_;
   int v_texture_location_;
   int alpha_location_;
   int yuv_matrix_location_;
   int yuv_adj_location_;
 };
 
 class FragmentShaderColor {
  public:
   FragmentShaderColor();
-  std::string GetShaderString() const;
+  std::string GetShaderString(TexCoordPrecision precision) const;
 
   void Init(WebKit::WebGraphicsContext3D*,
             unsigned program,
             bool using_bind_uniform,
             int* base_uniform_index);
   int edge_location() const { return -1; }
   int color_location() const { return color_location_; }
 
  private:
   int color_location_;
 };
 
 class FragmentShaderColorAA {
  public:
   FragmentShaderColorAA();
-  std::string GetShaderString() const;
+  std::string GetShaderString(TexCoordPrecision precision) const;
 
   void Init(WebKit::WebGraphicsContext3D*,
             unsigned program,
             bool using_bind_uniform,
             int* base_uniform_index);
   int edge_location() const { return edge_location_; }
   int color_location() const { return color_location_; }
 
  private:
   int edge_location_;
   int color_location_;
 };
 
 class FragmentShaderCheckerboard {
  public:
   FragmentShaderCheckerboard();
-  std::string GetShaderString() const;
+  std::string GetShaderString(TexCoordPrecision precision) const;
 
   void Init(WebKit::WebGraphicsContext3D*,
             unsigned program,
             bool using_bind_uniform,
             int* base_uniform_index);
   int alpha_location() const { return alpha_location_; }
   int tex_transform_location() const { return tex_transform_location_; }
   int frequency_location() const { return frequency_location_; }
   int color_location() const { return color_location_; }
 
  private:
   int alpha_location_;
   int tex_transform_location_;
   int frequency_location_;
   int color_location_;
 };
 
 } // namespace cc
 
 #endif  // CC_OUTPUT_SHADER_H_