Disallow drawing feedback loops.

gpu/command_buffer/service/gles2_cmd_decoder_unittest_drawing.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "gpu/command_buffer/service/gles2_cmd_decoder.h"
 
 #include "base/command_line.h"
 #include "base/strings/string_number_conversions.h"
 #include "gpu/command_buffer/common/gles2_cmd_format.h"
 #include "gpu/command_buffer/common/gles2_cmd_utils.h"
@@ skipping 296 matching lines @@
       .Times(1)
       .RetiresOnSaturation();
   EXPECT_EQ(error::kNoError, ExecuteCmd(draw_cmd));
   EXPECT_EQ(GL_NO_ERROR, GetGLError());
 
   // Setup Frame buffer.
   // needs to be 1x1 or else it's not renderable.
   const GLsizei kWidth = 1;
   const GLsizei kHeight = 1;
   const GLenum kFormat = GL_RGB;
-  DoBindTexture(GL_TEXTURE_2D, client_texture_id_, kServiceTextureId);
+  // Use a different texture for framebuffer to avoid drawing feedback loops.
+  EXPECT_CALL(*gl_, GenTextures(_, _))
+      .WillOnce(SetArgumentPointee<1>(kNewServiceId))
+      .RetiresOnSaturation();
+  GenHelper<cmds::GenTexturesImmediate>(kNewClientId);
+  DoBindTexture(GL_TEXTURE_2D, kNewClientId, kNewServiceId);
   // Pass some data so the texture will be marked as cleared.
   DoTexImage2D(GL_TEXTURE_2D,
                0,
                kFormat,
                kWidth,
                kHeight,
                0,
                kFormat,
                GL_UNSIGNED_BYTE,
                kSharedMemoryId,
                kSharedMemoryOffset);
   DoBindFramebuffer(
       GL_FRAMEBUFFER, client_framebuffer_id_, kServiceFramebufferId);
   DoFramebufferTexture2D(GL_FRAMEBUFFER,
                          GL_COLOR_ATTACHMENT0,
                          GL_TEXTURE_2D,
-                         client_texture_id_,
-                         kServiceTextureId,
+                         kNewClientId,
+                         kNewServiceId,
                          0,
                          GL_NO_ERROR);
+  DoBindTexture(GL_TEXTURE_2D, client_texture_id_, kServiceTextureId);
   EXPECT_CALL(*gl_, CheckFramebufferStatusEXT(GL_FRAMEBUFFER))
       .WillOnce(Return(GL_FRAMEBUFFER_COMPLETE))
       .RetiresOnSaturation();
 
   // This time state needs to be set.
   SetupExpectationsForApplyingDirtyState(false,   // Framebuffer is RGB
                                          false,   // Framebuffer has depth
                                          false,   // Framebuffer has stencil
                                          0x1110,  // color bits
                                          false,   // depth mask
@@ skipping 2033 matching lines @@
       .Times(1)
       .RetiresOnSaturation();
   DrawArrays cmd;
   cmd.Init(GL_TRIANGLES, 0, kNumVertices);
   EXPECT_EQ(error::kNoError, ExecuteCmd(cmd));
   EXPECT_EQ(GL_NO_ERROR, GetGLError());
 }
 
 }  // namespace gles2
 }  // namespace gpu