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

gpu/command_buffer/build_gles2_cmd_buffer.py

Index: gpu/command_buffer/build_gles2_cmd_buffer.py
diff --git a/gpu/command_buffer/build_gles2_cmd_buffer.py b/gpu/command_buffer/build_gles2_cmd_buffer.py
index cad0c00a7a02bbb94be515703d95eaa1f87b4185..2a44c43f77af0dc54360a0b18211451bce273f9b 100755
--- a/gpu/command_buffer/build_gles2_cmd_buffer.py
+++ b/gpu/command_buffer/build_gles2_cmd_buffer.py
@@ -1508,11 +1508,14 @@ _NAMED_TYPE_INFO = {
       'GL_RGBA',
     ],
     'valid_es3': [
+      'GL_RED',
+      'GL_RED_INTEGER',
+      'GL_RG',
+      'GL_RG_INTEGER',
+      'GL_RGB_INTEGER',
       'GL_RGBA_INTEGER',
-    ],
-    'deprecated_es3': [

[Ken Russell (switch to Gerrit), 2015/08/26 01:00:44]

What's the consequence of un-deprecating these?

[Zhenyao Mo, 2015/08/26 01:11:05]

It's a mistake to deprecate them in the first place.

-      'GL_ALPHA',
-      'GL_RGB',
+      'GL_LUMINANCE',
+      'GL_LUMINANCE_ALPHA',

[Ken Russell (switch to Gerrit), 2015/08/26 01:00:43]

It looks to me like GL_LUMINANCE and GL_LUMINANCE_ALPHA are defined in Table 3.3
rather than 3.2 in the spec, and that the implementation color read format and
type are defined as coming from Table 3.2. Can you verify?

[Zhenyao Mo, 2015/08/26 01:11:04]

3.2 defines the sized ones, and 3.3 defines the unsized ones.  Both should be
valid.

[Ken Russell (switch to Gerrit), 2015/08/26 01:53:32]

Not sure about that. ES 3.0.4 section 4.4.4 "Framebuffer Completeness":

"An internal format is color-renderable if it is one of the formats from table
3.13 noted as color-renderable or if it is unsized format RGBA or RGB. No other
formats, including compressed internal formats, are color-renderable."

I think this excludes LUMINANCE and LUMINANCE_ALPHA type textures as being valid
framebuffer object color attachments, so it's not possible to call ReadPixels
when a framebuffer is using that format and type.

     ],
   },
   'PixelType': {
@@ -1600,20 +1603,16 @@ _NAMED_TYPE_INFO = {
       'GL_UNSIGNED_SHORT_4_4_4_4',
       'GL_UNSIGNED_SHORT_5_5_5_1',
     ],
-    'invalid': [
-      'GL_SHORT',
-    ],
     'valid_es3': [
+      'GL_BYTE',
+      'GL_UNSIGNED_SHORT',
+      'GL_SHORT',
       'GL_UNSIGNED_INT',
       'GL_INT',
+      'GL_HALF_FLOAT',
       'GL_FLOAT',
       'GL_UNSIGNED_INT_2_10_10_10_REV',
     ],
-    'deprecated_es3': [
-      'GL_UNSIGNED_SHORT_5_6_5',
-      'GL_UNSIGNED_SHORT_4_4_4_4',
-      'GL_UNSIGNED_SHORT_5_5_5_1',

[Ken Russell (switch to Gerrit), 2015/08/26 01:00:43]

Similarly, what's the consequence of un-deprecating these?

[Zhenyao Mo, 2015/08/26 01:11:04]

The same, table 3.3 (valid unsized ones) should also be included

-    ],
   },
   'RenderBufferFormat': {
     'type': 'GLenum',