Add GL_TEXTURE_EXTERNAL_OES as supported texture target for CHROMIUM_map_image.

ui/gl/gl_image_shm.cc

Index: ui/gl/gl_image_shm.cc
diff --git a/ui/gl/gl_image_shm.cc b/ui/gl/gl_image_shm.cc
index 076b1fcb79379acb8e21d8fa2481d645500e4179..8f7dec5ae45e9e1a5ae86bcfeacf448941f68f0b 100644
--- a/ui/gl/gl_image_shm.cc
+++ b/ui/gl/gl_image_shm.cc
@@ -6,7 +6,7 @@
 
 #include "base/debug/trace_event.h"
 #include "base/process/process_handle.h"
-#include "ui/gl/gl_bindings.h"
+#include "ui/gl/gl_surface_egl.h"

[reveman, 2014/03/17 01:13:38]

why is gl_bindings.h not enough?

 
 namespace gfx {
 
@@ -64,8 +64,9 @@ GLenum BytesPerPixel(unsigned internalformat) {
 
 GLImageShm::GLImageShm(gfx::Size size, unsigned internalformat)
     : size_(size),
-      internalformat_(internalformat) {
-}
+      internalformat_(internalformat),
+      external_texture_id_(0),
+      egl_image_(EGL_NO_IMAGE_KHR) {}
 
 GLImageShm::~GLImageShm() {
   Destroy();
@@ -95,9 +96,40 @@ bool GLImageShm::Initialize(gfx::GpuMemoryBufferHandle buffer) {
   return true;
 }
 
-void GLImageShm::Destroy() {
+void GLImageShm::CreateTexture2D() {
+  glGenTextures(1, &external_texture_id_);
+  glBindTexture(GL_TEXTURE_2D, external_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);
+}
+
+bool GLImageShm::CreateEGLImage() {
+  EGLint egl_attrib_list[] = {EGL_GL_TEXTURE_LEVEL_KHR, 0,  // mip-level.
+                              EGL_IMAGE_PRESERVED_KHR, EGL_TRUE, EGL_NONE};
+  egl_image_ =
+      eglCreateImageKHR(eglGetCurrentDisplay(),
+                        eglGetCurrentContext(),
+                        EGL_GL_TEXTURE_2D_KHR,
+                        reinterpret_cast<EGLClientBuffer>(external_texture_id_),
+                        egl_attrib_list);
+  if (egl_image_ == EGL_NO_IMAGE_KHR) {
+    EGLint error = eglGetError();
+    LOG(ERROR) << "Error creating EGLImage: " << error;
+    return false;
+  }
+  return true;
 }
 
+void GLImageShm::ReleaseEGLImageandTexture() {
+  if (egl_image_ != EGL_NO_IMAGE_KHR)
+    eglDestroyImageKHR(eglGetCurrentDisplay(), egl_image_);
+  if (external_texture_id_)
+    glDeleteTextures(1, &external_texture_id_);
+}
+
+void GLImageShm::Destroy() { ReleaseEGLImageandTexture(); }
+
 gfx::Size GLImageShm::GetSize() {
   return size_;
 }
@@ -114,17 +146,45 @@ bool GLImageShm::BindTexImage(unsigned target) {
     return false;
   }
 
-  DCHECK(shared_memory_->memory());
-  glTexImage2D(target,
-               0,  // mip level
-               TextureFormat(internalformat_),
-               size_.width(),
-               size_.height(),
-               0,  // border
-               DataFormat(internalformat_),
-               DataType(internalformat_),
-               shared_memory_->memory());
+  if (target != GL_TEXTURE_EXTERNAL_OES) {
+    DCHECK(shared_memory_->memory());
+    glTexImage2D(target,
+                 0,  // mip level
+                 TextureFormat(internalformat_),
+                 size_.width(),
+                 size_.height(),
+                 0,  // border
+                 DataFormat(internalformat_),
+                 DataType(internalformat_),
+                 shared_memory_->memory());
+  } else {
+    // Save current GL state.
+    GLint current_texture_id = 0;
+    glGetIntegerv(GL_TEXTURE_BINDING_EXTERNAL_OES, &current_texture_id);

[reveman, 2014/03/15 14:08:45]

EXTERNAL_OES binding is not the state you're changing. It's the TEXTURE_2D
binding you're changing.

[reveman, 2014/03/17 01:13:38]

Also, use ScopedTextureBinder here instead.

+    CreateTexture2D();
+
+    DCHECK(shared_memory_->memory());
+    glTexImage2D(GL_TEXTURE_2D,
+                 0,  // mip level
+                 TextureFormat(internalformat_),
+                 size_.width(),
+                 size_.height(),
+                 0,  // border
+                 DataFormat(internalformat_),
+                 DataType(internalformat_),
+                 shared_memory_->memory());
+
+    if (!CreateEGLImage()) {
+      shared_memory_->Unmap();
+      return false;
+    }
+    glBindTexture(GL_TEXTURE_2D, external_texture_id_);
+    glEGLImageTargetTexture2DOES(target, egl_image_);
 
+    // Restore GL State and release.
+    ReleaseEGLImageandTexture();

[reveman, 2014/03/15 14:08:45]

what's the point of having egl_image_ and external_texture_id_ members if the
lifetime of them doesn't go beyond this function?

You can reuse the egl image and the external texture id if you use
glTexSubImage2D. If not already, please look at
http://www.khronos.org/registry/egl/extensions/KHR/EGL_KHR_gl_image.txt to
understand how this extension works.

[reveman, 2014/03/17 01:13:38]

Don't get hung up on reusing the egl image though. I'd like to keep this as
clean and simple as possible. If calling TexImage2D and re-creating the egl
image with each bind is cleaner, then do that. I'm pretty sure you still have to
keep the egl image and texture around as members though. Binding the egl image
to a texture and then destroying the egl image doesn't seem right.

+    glBindTexture(target, current_texture_id);
+  }
   shared_memory_->Unmap();
   return true;
 }