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..4f1fae28ddbbef0f2a28a74acf1681571f31a2fb 100644
--- a/gpu/command_buffer/service/framebuffer_manager.cc
+++ b/gpu/command_buffer/service/framebuffer_manager.cc
@@ -102,7 +102,8 @@ class RenderbufferAttachment
   }
 
   virtual bool ValidForAttachmentType(
-      GLenum attachment_type, uint32 max_color_attachments) OVERRIDE {
+      GLenum attachment_type, uint32 max_color_attachments,
+      bool) OVERRIDE {
     uint32 need = GLES2Util::GetChannelsNeededForAttachmentType(
         attachment_type, max_color_attachments);
     uint32 have = GLES2Util::GetChannelsForFormat(internal_format());
@@ -216,7 +217,8 @@ class TextureAttachment
   }
 
   virtual bool ValidForAttachmentType(
-      GLenum attachment_type, uint32 max_color_attachments) OVERRIDE {
+      GLenum attachment_type, uint32 max_color_attachments,
+      bool allow_float_color_attachment) OVERRIDE {
     GLenum type = 0;
     GLenum internal_format = 0;
     if (!texture_ref_->texture()->GetLevelType(
@@ -233,6 +235,11 @@ class TextureAttachment
         internal_format == GL_LUMINANCE_ALPHA) {
       return false;
     }
+    if (type == GL_FLOAT &&
+        (!allow_float_color_attachment ||
+         (internal_format != GL_RGBA32F && internal_format != GL_RGB32F))) {
+      return false;
+    }
     return (need & have) != 0;
   }
 
@@ -406,7 +413,8 @@ GLenum Framebuffer::GetColorAttachmentTextureType() const {
   return attachment->texture_type();
 }
 
-GLenum Framebuffer::IsPossiblyComplete() const {
+GLenum Framebuffer::IsPossiblyComplete(
+    bool allow_float_color_attachment) const {
   if (attachments_.empty()) {
     return GL_FRAMEBUFFER_INCOMPLETE_MISSING_ATTACHMENT;
   }
@@ -418,7 +426,8 @@ 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_,
+                                            allow_float_color_attachment)) {
       return GL_FRAMEBUFFER_INCOMPLETE_ATTACHMENT;
     }
     if (width < 0) {