Adding YUVA support for enabling Alpha Playback

cc/output/shader.cc

 // 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.
 
 #include "cc/output/shader.h"
 
 #include "base/basictypes.h"
 #include "base/logging.h"
 #include "third_party/WebKit/Source/Platform/chromium/public/WebGraphicsContext3D.h"
 
@@ skipping 895 matching lines @@
       float y_raw = texture2D(y_texture, v_texCoord).x;
       float u_unsigned = texture2D(u_texture, v_texCoord).x;
       float v_unsigned = texture2D(v_texture, v_texCoord).x;
       vec3 yuv = vec3(y_raw, u_unsigned, v_unsigned) + yuv_adj;
       vec3 rgb = yuv_matrix * yuv;
       gl_FragColor = vec4(rgb, float(1)) * alpha;
     }
   );
 }
 
+FragmentShaderYUVAVideo::FragmentShaderYUVAVideo()
+    : y_texture_location_(-1)

[enne (OOO), 2013/04/04 22:08:44]

style nit: commas don't go at the beginning of lines.

[vignesh, 2013/04/05 22:00:28]

Done.

+    , u_texture_location_(-1)
+    , v_texture_location_(-1)
+    , a_texture_location_(-1)
+    , alpha_location_(-1)
+    , yuv_matrix_location_(-1)
+    , yuv_adj_location_(-1)
+{
+}
+
+void FragmentShaderYUVAVideo::Init(WebGraphicsContext3D* context,
+                                   unsigned program,
+                                   bool using_bind_uniform,
+                                   int* base_uniform_index)
+{

[enne (OOO), 2013/04/04 22:08:44]

style nit: { goes on the previous line.  How did this pass presubmit?

[vignesh, 2013/04/05 22:00:28]

Sorry, but i did not get any presubmit warnings. Not sure why.

Done.

+    static const char* shader_uniforms[] = {

[enne (OOO), 2013/04/04 22:08:44]

style nit: don't use a 4 space indent

[vignesh, 2013/04/05 22:00:28]

Done.

+        "y_texture",
+        "u_texture",
+        "v_texture",
+        "a_texture",
+        "alpha",
+        "cc_matrix",
+        "yuv_adj",
+    };
+    int locations[7];
+
+    GetProgramUniformLocations(context,
+                               program,
+                               shader_uniforms,
+                               arraysize(shader_uniforms),
+                               arraysize(locations),
+                               locations,
+                               using_bind_uniform,
+                               base_uniform_index);
+
+    y_texture_location_ = locations[0];
+    u_texture_location_ = locations[1];
+    v_texture_location_ = locations[2];
+    a_texture_location_ = locations[3];
+    alpha_location_ = locations[4];
+    yuv_matrix_location_ = locations[5];
+    yuv_adj_location_ = locations[6];
+
+    DCHECK(y_texture_location_ != -1 && u_texture_location_ != -1 &&
+           v_texture_location_ != -1 && a_texture_location_ != -1 &&
+           alpha_location_ != -1 && yuv_matrix_location_ != -1 &&
+           yuv_adj_location_ != -1);
+}
+
+std::string FragmentShaderYUVAVideo::GetShaderString() const
+{
+    return SHADER(
+        precision mediump float;
+        precision mediump int;
+        varying vec2 y_texCoord;
+        varying vec2 uv_texCoord;

[enne (OOO), 2013/04/04 22:08:44]

What does this second varying parameter get hooked up to? Doesn't the vertex
shader only emit one varying parameter?

+        uniform sampler2D y_texture;
+        uniform sampler2D u_texture;
+        uniform sampler2D v_texture;
+        uniform sampler2D a_texture;
+        uniform float alpha;
+        uniform vec3 yuv_adj;
+        uniform mat3 cc_matrix;
+        void main()
+        {
+            float y_raw = texture2D(y_texture, y_texCoord).x;
+            float u_unsigned = texture2D(u_texture, uv_texCoord).x;
+            float v_unsigned = texture2D(v_texture, uv_texCoord).x;
+            float a_raw = texture2D(a_texture, y_texCoord).x;
+            vec3 yuv = vec3(y_raw, u_unsigned, v_unsigned) + yuv_adj;
+            vec3 rgb = cc_matrix * yuv;
+            gl_FragColor = vec4(rgb, float(1)) * (a_raw * alpha);
+        }
+    );
+}
+
 FragmentShaderColor::FragmentShaderColor()
     : color_location_(-1) {}
 
 void FragmentShaderColor::Init(WebGraphicsContext3D* context,
                                unsigned program,
                                bool using_bind_uniform,
                                int* base_uniform_index) {
   static const char* shader_uniforms[] = {
     "color",
   };
@@ skipping 122 matching lines @@
       vec2 texCoord = clamp(v_texCoord, 0.0, 1.0) * texTransform.zw +
           texTransform.xy;
       vec2 coord = mod(floor(texCoord * frequency * 2.0), 2.0);
       float picker = abs(coord.x - coord.y);
       gl_FragColor = mix(color1, color2, picker) * alpha;
     }
   );
 }
 
 }  // namespace cc