update getFramebufferAttachmentParameter for WebGL 2

Source/core/html/canvas/WebGL2RenderingContextBase.cpp

 // Copyright 2015 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 "config.h"
 #include "core/html/canvas/WebGL2RenderingContextBase.h"
 
 #include "bindings/core/v8/WebGLAny.h"
 #include "core/html/HTMLCanvasElement.h"
 #include "core/html/HTMLImageElement.h"
@@ skipping 1443 matching lines @@
         // FIXME: Some of these ES3 buffer targets may require additional state tracking.
         break;
     default:
         synthesizeGLError(GL_INVALID_ENUM, functionName, "invalid target");
         return false;
     }
 
     return true;
 }
 
+bool WebGL2RenderingContextBase::validateGetFramebufferAttachmentParameterFunc(const char* functionName, GLenum target, GLenum attachment)
+{
+    if (target != GL_FRAMEBUFFER && target != GL_READ_FRAMEBUFFER && target != GL_DRAW_FRAMEBUFFER) {

[Ken Russell (switch to Gerrit), 2015/04/28 05:43:23]

Please make sure that this code eventually uses the new validation function from
 https://codereview.chromium.org/1099853002/ .

[yunchao, 2015/04/29 11:13:11]

Done.

+        synthesizeGLError(GL_INVALID_ENUM, functionName, "invalid target");
+        return false;
+    }
+    ASSERT(m_framebufferBinding || drawingBuffer());
+    if (!m_framebufferBinding) {
+    // for the default framebuffer
+        switch (attachment) {
+        case GL_BACK:
+        case GL_DEPTH:
+        case GL_STENCIL:
+            break;
+        default:
+            synthesizeGLError(GL_INVALID_ENUM, functionName, "invalid attachment");
+            return false;
+        }
+    } else {
+    // for the FBO
+        switch (attachment) {
+        case GL_COLOR_ATTACHMENT0:
+        case GL_DEPTH_ATTACHMENT:
+        case GL_STENCIL_ATTACHMENT:
+            break;
+        case GL_DEPTH_STENCIL_ATTACHMENT:
+            if (m_framebufferBinding->getAttachmentObject(GL_DEPTH_STENCIL_ATTACHMENT) || (m_framebufferBinding->getAttachmentObject(GL_DEPTH_ATTACHMENT) == m_framebufferBinding->getAttachmentObject(GL_STENCIL_ATTACHMENT)))
+                break;
+        default:
+            if (attachment > GL_COLOR_ATTACHMENT0
+                && attachment < static_cast<GLenum>(GL_COLOR_ATTACHMENT0 + maxColorAttachments()))
+                break;
+            synthesizeGLError(GL_INVALID_ENUM, functionName, "invalid attachment");
+            return false;
+        }
+    }
+    return true;
+}
+
+ScriptValue WebGL2RenderingContextBase::getFramebufferAttachmentParameter(ScriptState* scriptState, GLenum target, GLenum attachment, GLenum pname)
+{
+    if (isContextLost() || !validateGetFramebufferAttachmentParameterFunc("getFramebufferAttachmentParameter", target, attachment))
+        return ScriptValue::createNull(scriptState);
+
+    ASSERT(!m_framebufferBinding || m_framebufferBinding->object());

[Ken Russell (switch to Gerrit), 2015/04/28 05:43:23]

target can be either GL_READ_FRAMEBUFFER or GL_DRAW_FRAMEBUFFER.
m_framebufferBinding is only the DRAW_FRAMEBUFFER. As in
https://codereview.chromium.org/1099853002/ , this code needs to be updated to
handle both binding points.

[yunchao, 2015/04/29 11:13:11]

Done.

+
+    WebGLSharedObject* attachmentObject = m_framebufferBinding ? m_framebufferBinding->getAttachmentObject(attachment) : 0;
+    if (m_framebufferBinding && !attachmentObject) {
+        if (pname == GL_FRAMEBUFFER_ATTACHMENT_OBJECT_TYPE)
+            return WebGLAny(scriptState, GL_NONE);
+        if (pname == GL_FRAMEBUFFER_ATTACHMENT_OBJECT_NAME)
+            return WebGLAny(scriptState, 0);
+        synthesizeGLError(GL_INVALID_OPERATION, "getFramebufferAttachmentParameter", "invalid parameter name");
+        return ScriptValue::createNull(scriptState);
+    }
+
+    switch (pname) {
+    case GL_FRAMEBUFFER_ATTACHMENT_OBJECT_TYPE:
+        if (!attachmentObject) {
+            ASSERT(!m_framebufferBinding);
+            return WebGLAny(scriptState, GL_FRAMEBUFFER_DEFAULT);
+        }
+        ASSERT(attachmentObject->isTexture() || attachmentObject->isRenderbuffer());
+        if (attachmentObject->isTexture())
+            return WebGLAny(scriptState, GL_TEXTURE);
+        if (attachmentObject->isRenderbuffer())
+            return WebGLAny(scriptState, GL_RENDERBUFFER);
+        break;
+    case GL_FRAMEBUFFER_ATTACHMENT_OBJECT_NAME:
+        if (!attachmentObject)
+            break;
+        return WebGLAny(scriptState, PassRefPtrWillBeRawPtr<WebGLObject>(attachmentObject));
+    case GL_FRAMEBUFFER_ATTACHMENT_TEXTURE_CUBE_MAP_FACE:
+    case GL_FRAMEBUFFER_ATTACHMENT_TEXTURE_LAYER:
+    case GL_FRAMEBUFFER_ATTACHMENT_TEXTURE_LEVEL:
+        if (!attachmentObject || !attachmentObject->isTexture())
+            break;
+    case GL_FRAMEBUFFER_ATTACHMENT_RED_SIZE:
+    case GL_FRAMEBUFFER_ATTACHMENT_GREEN_SIZE:
+    case GL_FRAMEBUFFER_ATTACHMENT_BLUE_SIZE:
+    case GL_FRAMEBUFFER_ATTACHMENT_ALPHA_SIZE:
+    case GL_FRAMEBUFFER_ATTACHMENT_DEPTH_SIZE:
+    case GL_FRAMEBUFFER_ATTACHMENT_STENCIL_SIZE:
+        {
+            GLint value = 0;
+            webContext()->getFramebufferAttachmentParameteriv(target, attachment, pname, &value);

[Ken Russell (switch to Gerrit), 2015/04/28 05:43:23]

This will return an incorrect answer if the DrawingBuffer's FBO (which is
WebGL's default framebuffer) is bound. The code needs to be updated to handle
that case.

[yunchao, 2015/04/29 11:13:11]

Agreed. The latest patch set has updated bindFramebuffer. If binding to the
default Framebuffer, the latest patch set would bind to DrawingBuffer's FBO for
the given target, so the query would be correct.

+            return WebGLAny(scriptState, value);
+        }
+    case GL_FRAMEBUFFER_ATTACHMENT_COMPONENT_TYPE:
+    case GL_FRAMEBUFFER_ATTACHMENT_COLOR_ENCODING:
+        {
+            GLint value = 0;
+            webContext()->getFramebufferAttachmentParameteriv(target, attachment, pname, &value);
+            return WebGLAny(scriptState, static_cast<unsigned>(value));
+        }
+    default:
+        break;
+    }
+    synthesizeGLError(GL_INVALID_ENUM, "getFramebufferAttachmentParameter", "invalid parameter name");
+    return ScriptValue::createNull(scriptState);
+}
+
 DEFINE_TRACE(WebGL2RenderingContextBase)
 {
     visitor->trace(m_readFramebufferBinding);
     WebGLRenderingContextBase::trace(visitor);
 }
 
 WebGLTexture* WebGL2RenderingContextBase::validateTextureBinding(const char* functionName, GLenum target, bool useSixEnumsForCubeMap)
 {
     switch (target) {
     // FIXME: add 2D Array texture binding point and 3D texture binding point.
@@ skipping 42 matching lines @@
             GLfloat value = 0.f;
             webContext()->getTexParameterfv(target, pname, &value);
             return WebGLAny(scriptState, value);
         }
     default:
         return WebGLRenderingContextBase::getTexParameter(scriptState, target, pname);
     }
 }
 
 } // namespace blink