Update CopyTexImage2D to do internal format validation in ES3

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 a555557a96e6859dde37b5d94e1558de7b50f297..c56d28f9d45c9201b6c1339afffe8476c991f145 100644
--- a/gpu/command_buffer/service/gles2_cmd_decoder.cc
+++ b/gpu/command_buffer/service/gles2_cmd_decoder.cc
@@ -1567,6 +1567,10 @@ class GLES2DecoderImpl : public GLES2Decoder,
   // attached. Generates GL error if not.
   bool CheckBoundReadFramebufferColorAttachment(const char* func_name);
 
+  // Get the value of GL_FRAMEBUFFER_ATTACHMENT_COLOR_ENCODING for the
+  // framebuffer attachment corresponding to the read buffer.
+  GLint GetReadFramebufferAttachmentColorEncoding();
+
   // Check that the currently bound read framebuffer's color image
   // isn't the target texture of the glCopyTex{Sub}Image2D.
   bool FormsTextureCopyingFeedbackLoop(TextureRef* texture, GLint level);
@@ -4019,6 +4023,16 @@ bool GLES2DecoderImpl::CheckBoundReadFramebufferColorAttachment(
   return true;
 }
 
+GLint GLES2DecoderImpl::GetReadFramebufferAttachmentColorEncoding() {
+  GLenum target = features().chromium_framebuffer_multisample ?
+      GL_READ_FRAMEBUFFER_EXT : GL_FRAMEBUFFER_EXT;
+  GLint v = GL_NONE;
+  glGetFramebufferAttachmentParameterivEXT(
+      target, GL_COLOR_ATTACHMENT0,
+      GL_FRAMEBUFFER_ATTACHMENT_COLOR_ENCODING, &v);
+  return v;
+}
+
 bool GLES2DecoderImpl::FormsTextureCopyingFeedbackLoop(
     TextureRef* texture, GLint level) {
   Framebuffer* framebuffer = features().chromium_framebuffer_multisample ?
@@ -11003,6 +11017,23 @@ void GLES2DecoderImpl::DoCopyTexImage2D(
     return;
   }
 
+  if (feature_info_->IsES3Enabled()) {
+    GLint color_encoding = GetReadFramebufferAttachmentColorEncoding();
+    if ((GL_LINEAR == color_encoding &&
+         GLES2Util::IsSRGBFormat(internal_format)) ||

[Zhenyao Mo, 2015/10/13 01:22:49]

One optimization is, instead of asking IsSRGBFormat, you can have a function
called GetColorEncodingFromInternalFormat().  Then you don't even have to call
the gl function, you can just infer from read_format.  Also, you will not need
to call IsSRGBFormat() twice here, you can just do if (color_endoding !=
GetReadFramebufferAttachmentColorEncoding())

Just an idea.

[qiankun, 2015/10/13 14:28:01]

Thanks for this suggestion! I implemented this optimization.

+        (GL_SRGB == color_encoding &&
+         !GLES2Util::IsSRGBFormat(internal_format)) ||
+        GLES2Util::IsFloatFormat(internal_format) ||
+        (GLES2Util::IsSignedIntegerFormat(internal_format) !=
+         GLES2Util::IsSignedIntegerFormat(read_format)) ||
+        (GLES2Util::IsUnsignedIntegerFormat(internal_format) !=
+         GLES2Util::IsUnsignedIntegerFormat(read_format))) {
+      LOCAL_SET_GL_ERROR(
+          GL_INVALID_OPERATION, "glCopyTexImage2D", "incompatible format");
+      return;
+    }
+  }
+
   if ((channels_needed & (GLES2Util::kDepth | GLES2Util::kStencil)) != 0) {
     LOCAL_SET_GL_ERROR(
         GL_INVALID_OPERATION,