Implement support for rendering to 32-bit float textures on ES3

gpu/command_buffer/service/framebuffer_manager.cc

Index: gpu/command_buffer/service/framebuffer_manager.cc
diff --git a/gpu/command_buffer/service/framebuffer_manager.cc b/gpu/command_buffer/service/framebuffer_manager.cc
index 48e503cb45b3d1e64986d369edfe70d7f3557c16..6f2500e14fc4b300434381e4dd717f8c9996de67 100644
--- a/gpu/command_buffer/service/framebuffer_manager.cc
+++ b/gpu/command_buffer/service/framebuffer_manager.cc
@@ -6,6 +6,7 @@
 #include "base/logging.h"
 #include "base/strings/stringprintf.h"
 #include "gpu/command_buffer/common/gles2_cmd_utils.h"
+#include "gpu/command_buffer/service/feature_info.h"
 #include "gpu/command_buffer/service/renderbuffer_manager.h"
 #include "gpu/command_buffer/service/texture_manager.h"
 #include "ui/gl/gl_bindings.h"
@@ -102,7 +103,8 @@ class RenderbufferAttachment
   }
 
   virtual bool ValidForAttachmentType(
-      GLenum attachment_type, uint32 max_color_attachments) OVERRIDE {
+      GLenum attachment_type, uint32 max_color_attachments,
+      const FeatureInfo*) OVERRIDE {
     uint32 need = GLES2Util::GetChannelsNeededForAttachmentType(
         attachment_type, max_color_attachments);
     uint32 have = GLES2Util::GetChannelsForFormat(internal_format());
@@ -216,7 +218,8 @@ class TextureAttachment
   }
 
   virtual bool ValidForAttachmentType(
-      GLenum attachment_type, uint32 max_color_attachments) OVERRIDE {
+      GLenum attachment_type, uint32 max_color_attachments,
+      const FeatureInfo* feature_info) OVERRIDE {
     GLenum type = 0;
     GLenum internal_format = 0;
     if (!texture_ref_->texture()->GetLevelType(
@@ -233,6 +236,14 @@ class TextureAttachment
         internal_format == GL_LUMINANCE_ALPHA) {
       return false;
     }
+    if ((internal_format == GL_RGBA32F &&
+         !feature_info->feature_flags().chromium_color_buffer_float_rgba) ||
+        (internal_format == GL_RGB32F &&
+         !feature_info->feature_flags().chromium_color_buffer_float_rgb) ||
+        (type == GL_FLOAT &&
+         internal_format != GL_RGBA32F && internal_format != GL_RGB32F)) {
+      return false;

[Ken Russell (switch to Gerrit), 2014/02/11 00:37:23]

I'm pretty sure this is going to break ANGLE's ability to render to
floating-point textures, since it currently advertises itself as an ES2
implementation but "happens" (deliberately, and in a way that violates specs,
sorry about that) to support rendering to GL_FLOAT/GL_RGBA textures.

Can you confirm this?

Can you think of a way to relax these checks slightly to avoid breaking FP
texture rendering on Windows? In other words, if
GL_CHROMIUM_color_buffer_float_rgb / GL_CHROMIUM_color_buffer_float_rgba are
advertised, then be strict about using a sized internal format when rendering to
FP textures?

[oetuaho-nv, 2014/02/11 12:42:16]

Right, I should have realized that ANGLE doesn't follow GL specs in any way as
it comes to rendering to float textures. I can change the patch so that when
is_angle in FeatureInfo is true, the unsized internalformats are still accepted
here. To fix this better, support for the sized internalformats could be added
to ANGLE and it could expose an ANGLE_color_buffer_float extension, but I won't
have time for implementing that.

+    }
     return (need & have) != 0;
   }
 
@@ -406,7 +417,7 @@ GLenum Framebuffer::GetColorAttachmentTextureType() const {
   return attachment->texture_type();
 }
 
-GLenum Framebuffer::IsPossiblyComplete() const {
+GLenum Framebuffer::IsPossiblyComplete(const FeatureInfo* feature_info) const {
   if (attachments_.empty()) {
     return GL_FRAMEBUFFER_INCOMPLETE_MISSING_ATTACHMENT;
   }
@@ -418,7 +429,8 @@ GLenum Framebuffer::IsPossiblyComplete() const {
     GLenum attachment_type = it->first;
     Attachment* attachment = it->second.get();
     if (!attachment->ValidForAttachmentType(attachment_type,
-                                            manager_->max_color_attachments_)) {
+                                            manager_->max_color_attachments_,
+                                            feature_info)) {
       return GL_FRAMEBUFFER_INCOMPLETE_ATTACHMENT;
     }
     if (width < 0) {