gpu: Extend CopyTextureCHROMIUM with support for copying part of source texture.

gpu/command_buffer/service/gles2_cmd_decoder.cc

Index: gpu/command_buffer/service/gles2_cmd_decoder.cc
diff --git a/gpu/command_buffer/service/gles2_cmd_decoder.cc b/gpu/command_buffer/service/gles2_cmd_decoder.cc
index 7b0f522e3631afc080582c7a2de331de22f58d8b..e48efc8235c46cb52a57a7ead5e0bd38906b48ec 100644
--- a/gpu/command_buffer/service/gles2_cmd_decoder.cc
+++ b/gpu/command_buffer/service/gles2_cmd_decoder.cc
@@ -1003,7 +1003,11 @@ class GLES2DecoderImpl : public GLES2Decoder,
                                 GLuint source_id,
                                 GLuint dest_id,
                                 GLint xoffset,
-                                GLint yoffset);
+                                GLint yoffset,
+                                GLint x,
+                                GLint y,
+                                GLsizei width,
+                                GLsizei height);
 
   // Wrapper for TexStorage2DEXT.
   void DoTexStorage2DEXT(
@@ -11995,7 +11999,11 @@ void GLES2DecoderImpl::DoCopySubTextureCHROMIUM(GLenum target,
                                                 GLuint source_id,
                                                 GLuint dest_id,
                                                 GLint xoffset,
-                                                GLint yoffset) {
+                                                GLint yoffset,
+                                                GLint x,
+                                                GLint y,
+                                                GLsizei width,
+                                                GLsizei height) {
   TRACE_EVENT0("gpu", "GLES2DecoderImpl::DoCopySubTextureCHROMIUM");
 
   TextureRef* source_texture_ref = GetTexture(source_id);
@@ -12036,6 +12044,13 @@ void GLES2DecoderImpl::DoCopySubTextureCHROMIUM(GLenum target,
   GLenum source_internal_format = 0;
   source_texture->GetLevelType(source_texture->target(), 0, &source_type,
                                &source_internal_format);
+  if (!source_texture->ValidForTexture(source_texture->target(), 0, x, y, 0,
+                                       width, height, 1, source_type)) {
+    LOCAL_SET_GL_ERROR(GL_INVALID_VALUE, "glCopySubTextureCHROMIUM",
+                       "source texture bad dimensions.");
+    return;
+  }
+
   GLenum dest_type = 0;
   GLenum dest_internal_format = 0;
   bool dest_level_defined = dest_texture->GetLevelType(
@@ -12046,8 +12061,7 @@ void GLES2DecoderImpl::DoCopySubTextureCHROMIUM(GLenum target,
     return;
   }
   if (!dest_texture->ValidForTexture(dest_texture->target(), 0, xoffset,
-                                     yoffset, 0, source_width, source_height,
-                                     1, dest_type)) {
+                                     yoffset, 0, width, height, 1, dest_type)) {
     LOCAL_SET_GL_ERROR(GL_INVALID_VALUE, "glCopySubTextureCHROMIUM",
                        "destination texture bad dimensions.");
     return;
@@ -12083,8 +12097,8 @@ void GLES2DecoderImpl::DoCopySubTextureCHROMIUM(GLenum target,
   bool ok = dest_texture->GetLevelSize(
       GL_TEXTURE_2D, 0, &dest_width, &dest_height, nullptr);
   DCHECK(ok);
-  if (xoffset != 0 || yoffset != 0 || source_width != dest_width ||
-      source_height != dest_height) {
+  if (xoffset != 0 || yoffset != 0 || width != dest_width ||
+      height != dest_height) {
     if (!texture_manager()->ClearTextureLevel(this, dest_texture_ref, target,
                                               0)) {
       LOCAL_SET_GL_ERROR(GL_OUT_OF_MEMORY, "glCopySubTextureCHROMIUM",
@@ -12104,31 +12118,19 @@ void GLES2DecoderImpl::DoCopySubTextureCHROMIUM(GLenum target,
   if (image && !unpack_flip_y_ && !unpack_premultiply_alpha_change) {
     glBindTexture(GL_TEXTURE_2D, dest_texture->service_id());
     if (image->CopyTexSubImage(GL_TEXTURE_2D, gfx::Point(xoffset, yoffset),
-                               gfx::Rect(0, 0, source_width, source_height))) {
+                               gfx::Rect(x, y, source_width, source_height))) {
       return;
     }
   }
 
   DoWillUseTexImageIfNeeded(source_texture, source_texture->target());
 
-  // GL_TEXTURE_EXTERNAL_OES texture requires apply a transform matrix
-  // before presenting.
-  if (source_texture->target() == GL_TEXTURE_EXTERNAL_OES) {
-    // TODO(hkuang): get the StreamTexture transform matrix in GPU process
-    // instead of using kIdentityMatrix crbug.com/226218.

[piman, 2015/05/22 21:11:03]

nit: can you keep the TODO and a reference to this bug?

[reveman, 2015/05/22 22:18:14]

We have this TODO and bug reference in GLES2DecoderImpl::DoCopyTextureCHROMIUM.
It was copied here when CopyTexture forked into CopyTexture+CopySubTexture. I
don't think we need to support stream textures in the CopySubTexture case and
applying a generic transformation matrix when performing a sub copy makes
everything more complicated.

+sievers to make sure I understand this correctly.

[no sievers, 2015/05/22 22:37:55]

This stuff is a bit unfortunate. You can put a TODO, although I don't think
anything would use CopyTexSubImage() with a stream texture (but the full copy
API is broken in the same way).

It might actually be easy to implement: We only need to worry about the matrix
if there is an image attached to the texture. So we'd probably need to have a
GLImage API to get the matrix which the StreamTexture implementation on Android
can then simply return. 

But again, this is much more interesting for CopyTextureCHROMIUM than
CopySubTexture touched in this patch.

[reveman, 2015/05/23 18:56:13]

Can we simply implement the copy in GLImage::CopyTexSubImage for stream
textures? I think that would be cleaner than pulling some magic matrix out the
generic GLImage.
Ok, thanks for explaining. I kept the TODO for now as it shouldn't hurt to have
it here.

-    copy_texture_CHROMIUM_->DoCopySubTextureWithTransform(
-        this, source_texture->target(), source_texture->service_id(),
-        dest_texture->service_id(), xoffset, yoffset, dest_width, dest_height,
-        source_width, source_height, unpack_flip_y_, unpack_premultiply_alpha_,
-        unpack_unpremultiply_alpha_, kIdentityMatrix);
-  } else {
-    copy_texture_CHROMIUM_->DoCopySubTexture(
-        this, source_texture->target(), source_texture->service_id(),
-        source_internal_format, dest_texture->service_id(),
-        dest_internal_format, xoffset, yoffset, dest_width, dest_height,
-        source_width, source_height, unpack_flip_y_, unpack_premultiply_alpha_,
-        unpack_unpremultiply_alpha_);
-  }
+  copy_texture_CHROMIUM_->DoCopySubTexture(
+      this, source_texture->target(), source_texture->service_id(),
+      source_internal_format, dest_texture->service_id(), dest_internal_format,
+      xoffset, yoffset, x, y, width, height, dest_width, dest_height,
+      source_width, source_height, unpack_flip_y_, unpack_premultiply_alpha_,
+      unpack_unpremultiply_alpha_);
 
   DoDidUseTexImageIfNeeded(source_texture, source_texture->target());
 }