Support rendering YUV formatted frames

data/yuv.frag

@@ -0,0 +1,32 @@
+#ifdef GL_ES
+precision highp float;
+#endif
+
+uniform sampler2D texture;
+uniform mat3 color_matrix;
+uniform float inv_gamma;
+uniform float blacklevel;
+
+varying vec2 top_left_uv;
+varying vec2 top_right_uv;
+varying vec2 bottom_left_uv;
+varying vec2 bottom_right_uv;
+
+void
+main()
+{
+    // Note the coordinates for texture samples need to be a varying, as the
+    // Mali-400 has this as a fast path allowing 32-bit floats. Otherwise
+    // they end up as 16-bit floats and that's not accurate enough.
+
+    vec4 samples = vec4(texture2D(texture, top_left_uv).r,
+    texture2D(texture, top_right_uv).r,
+    texture2D(texture, bottom_left_uv).r,
+    texture2D(texture, bottom_right_uv).r);
+    vec3 color = vec3(samples.x, samples.y, samples.z);
+
+    color *= color_matrix;
+    vec3 gamma_color = pow(color, vec3(inv_gamma));
+
+    gl_FragColor = vec4(gamma_color, 1);
+}