Fix ReadPixels implementation specific read format/type on desktop GL.

gpu/command_buffer/service/gles2_cmd_decoder.cc

Index: gpu/command_buffer/service/gles2_cmd_decoder.cc
diff --git a/gpu/command_buffer/service/gles2_cmd_decoder.cc b/gpu/command_buffer/service/gles2_cmd_decoder.cc
index 03f87167a04d297bb1826612e44f9736efba132d..fc94af76b9a81d95613893620f4d58226daa1020 100644
--- a/gpu/command_buffer/service/gles2_cmd_decoder.cc
+++ b/gpu/command_buffer/service/gles2_cmd_decoder.cc
@@ -5066,8 +5066,10 @@ bool GLES2DecoderImpl::GetHelper(
             if (glGetError() == GL_NO_ERROR)
               return true;
           }
-          *params = GLES2Util::GetPreferredGLReadPixelsFormat(
-              GetBoundReadFrameBufferInternalFormat());
+          GLES2Util::TargetESVersion target_es_version =
+              feature_info_->IsES3Enabled() ? GLES2Util::kES3 : GLES2Util::kES2;
+          *params = GLES2Util::GetGLReadPixelsImplementationFormat(
+              GetBoundReadFrameBufferInternalFormat(), target_es_version);
         }
         return true;
       case GL_IMPLEMENTATION_COLOR_READ_TYPE:
@@ -5080,9 +5082,12 @@ bool GLES2DecoderImpl::GetHelper(
             if (glGetError() == GL_NO_ERROR)
               return true;
           }
-          *params = GLES2Util::GetPreferredGLReadPixelsType(
+          GLES2Util::TargetESVersion target_es_version =
+              feature_info_->IsES3Enabled() ? GLES2Util::kES3 : GLES2Util::kES2;
+          *params = GLES2Util::GetGLReadPixelsImplementationType(
               GetBoundReadFrameBufferInternalFormat(),
-              GetBoundReadFrameBufferTextureType());
+              GetBoundReadFrameBufferTextureType(),
+              target_es_version);
         }
         return true;
       case GL_MAX_FRAGMENT_UNIFORM_VECTORS:
@@ -8752,9 +8757,6 @@ error::Error GLES2DecoderImpl::HandleReadPixels(uint32 immediate_data_size,
   std::vector<GLenum> accepted_formats;
   std::vector<GLenum> accepted_types;
   switch (src_internal_format) {
-    case GL_RGB10_A2UI:
-      accepted_formats.push_back(GL_RGBA);
-      accepted_types.push_back(GL_UNSIGNED_INT_2_10_10_10_REV);
     case GL_R8UI:
     case GL_R16UI:
     case GL_R32UI:
@@ -8763,6 +8765,7 @@ error::Error GLES2DecoderImpl::HandleReadPixels(uint32 immediate_data_size,
     case GL_RG32UI:
     // All the RGB_INTEGER formats are not renderable.
     case GL_RGBA8UI:
+    case GL_RGB10_A2UI:
     case GL_RGBA16UI:
     case GL_RGBA32UI:
       accepted_formats.push_back(GL_RGBA_INTEGER);
@@ -8780,6 +8783,13 @@ error::Error GLES2DecoderImpl::HandleReadPixels(uint32 immediate_data_size,
       accepted_formats.push_back(GL_RGBA_INTEGER);
       accepted_types.push_back(GL_INT);
       break;
+    case GL_RGB10_A2:
+      accepted_formats.push_back(GL_RGBA);
+      accepted_types.push_back(GL_UNSIGNED_BYTE);
+      // Special case with an extra supported format/type.
+      accepted_formats.push_back(GL_RGBA);
+      accepted_types.push_back(GL_UNSIGNED_INT_2_10_10_10_REV);
+      break;
     default:
       accepted_formats.push_back(GL_RGBA);
       {
@@ -8789,7 +8799,11 @@ error::Error GLES2DecoderImpl::HandleReadPixels(uint32 immediate_data_size,
           case GL_HALF_FLOAT_OES:
           case GL_FLOAT:
           case GL_UNSIGNED_INT_10F_11F_11F_REV:
-            accepted_types.push_back(GL_FLOAT);
+            if (!feature_info_->IsES3Enabled()) {
+              accepted_types.push_back(GL_UNSIGNED_BYTE);
+            } else {
+              accepted_types.push_back(GL_FLOAT);
+            }

[Ken Russell (switch to Gerrit), 2015/08/27 01:45:45]

I'm having difficulty understanding how the earlier code worked. It doesn't look
to me like it would advertise support for reading back RGBA/UNSIGNED_BYTE if a
floating-point framebuffer were bound -- but that would have broken the
conformance/extensions/oes-texture-float.html test.

[Zhenyao Mo, 2015/08/27 03:13:31]

It turned out we never tested RGBA/UNSIGNED_BYTE read back with float/half_float
textures in WebGL 1.  That's why the bug is never caught.

             break;
           default:
             accepted_types.push_back(GL_UNSIGNED_BYTE);