Use glTexSubImage2D while binding with external texture for map-image.

ui/gl/gl_image_shm.cc

 // Copyright 2013 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 "ui/gl/gl_image_shm.h"
 
 #include "base/debug/trace_event.h"
 #include "base/process/process_handle.h"
 #include "ui/gl/scoped_binders.h"
 
@@ skipping 121 matching lines @@
   if (!shared_memory_->Map(size)) {
     DVLOG(0) << "Failed to map shared memory.";
     return false;
   }
 
   DCHECK(shared_memory_->memory());
 
 #if defined(OS_WIN) || defined(USE_X11) || defined(OS_ANDROID) || \
     defined(USE_OZONE)
   if (target == GL_TEXTURE_EXTERNAL_OES) {
-    if (egl_image_ != EGL_NO_IMAGE_KHR)
-      eglDestroyImageKHR(GLSurfaceEGL::GetHardwareDisplay(), egl_image_);
-
-    if (!egl_texture_id_)
+    if (egl_image_ == EGL_NO_IMAGE_KHR) {

[sohanjg, 2014/03/28 12:36:20]

Should we add an extra check for egl_texture_id_ being 0.

[reveman, 2014/03/28 13:34:17]

Add a DCHECK_EQ(0, ..) check.

       glGenTextures(1, &egl_texture_id_);
 
-    {
+      {
+        ScopedTextureBinder texture_binder(GL_TEXTURE_2D, egl_texture_id_);
+        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
+        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
+        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
+
+        glTexImage2D(GL_TEXTURE_2D,
+                     0,  // mip level
+                     TextureFormat(internalformat_),
+                     size_.width(),
+                     size_.height(),
+                     0,  // border
+                     DataFormat(internalformat_),
+                     DataType(internalformat_),
+                     shared_memory_->memory());
+      }
+
+      EGLint attrs[] = {EGL_GL_TEXTURE_LEVEL_KHR, 0, EGL_IMAGE_PRESERVED_KHR,
+                        EGL_TRUE, EGL_NONE};
+      // Need to pass current EGL rendering context to eglCreateImageKHR for
+      // target type EGL_GL_TEXTURE_2D_KHR.
+      egl_image_ =
+          eglCreateImageKHR(GLSurfaceEGL::GetHardwareDisplay(),
+                            eglGetCurrentContext(),
+                            EGL_GL_TEXTURE_2D_KHR,
+                            reinterpret_cast<EGLClientBuffer>(egl_texture_id_),
+                            attrs);
+      DCHECK_NE(EGL_NO_IMAGE_KHR, egl_image_)
+          << "Error creating EGLImage: " << eglGetError();
+
+      glEGLImageTargetTexture2DOES(target, egl_image_);

[reveman, 2014/03/28 13:34:17]

You need to do this in the case below too. You're assuming that the client will
always attach the image to the same target and id otherwise.

+      DCHECK_EQ(static_cast<GLenum>(GL_NO_ERROR), glGetError());
+    } else {
       ScopedTextureBinder texture_binder(GL_TEXTURE_2D, egl_texture_id_);
-      glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
-      glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
-      glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
-
-      glTexImage2D(GL_TEXTURE_2D,
-                   0,  // mip level
-                   TextureFormat(internalformat_),
-                   size_.width(),
-                   size_.height(),
-                   0,  // border
-                   DataFormat(internalformat_),
-                   DataType(internalformat_),
-                   shared_memory_->memory());
+      glTexSubImage2D(GL_TEXTURE_2D,
+                      0,  // mip level
+                      0,  // x-offset
+                      0,  // y-offset
+                      size_.width(),
+                      size_.height(),
+                      DataFormat(internalformat_),
+                      DataType(internalformat_),
+                      shared_memory_->memory());
     }
 
-    EGLint attrs[] = {EGL_GL_TEXTURE_LEVEL_KHR, 0, EGL_IMAGE_PRESERVED_KHR,
-                      EGL_TRUE, EGL_NONE};
-    // Need to pass current EGL rendering context to eglCreateImageKHR for
-    // target type EGL_GL_TEXTURE_2D_KHR.
-    egl_image_ =
-        eglCreateImageKHR(GLSurfaceEGL::GetHardwareDisplay(),
-                          eglGetCurrentContext(),
-                          EGL_GL_TEXTURE_2D_KHR,
-                          reinterpret_cast<EGLClientBuffer>(egl_texture_id_),
-                          attrs);
-    DCHECK_NE(EGL_NO_IMAGE_KHR, egl_image_)
-        << "Error creating EGLImage: " << eglGetError();
-
-    glEGLImageTargetTexture2DOES(target, egl_image_);
-    DCHECK_EQ(static_cast<GLenum>(GL_NO_ERROR), glGetError());
-
     shared_memory_->Unmap();
     return true;
   }
 #endif
 
   DCHECK_NE(static_cast<GLenum>(GL_TEXTURE_EXTERNAL_OES), target);
   glTexImage2D(target,
                0,  // mip level
                TextureFormat(internalformat_),
                size_.width(),
                size_.height(),
                0,  // border
                DataFormat(internalformat_),
                DataType(internalformat_),
                shared_memory_->memory());
 
   shared_memory_->Unmap();
   return true;
 }
 
 }  // namespace gfx