[Reland] Fix ReadPixels from float fbo buffer in ES2/WebGL1.

third_party/WebKit/Source/modules/webgl/WebGLRenderingContextBase.cpp

 /*
  * Copyright (C) 2009 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 3530 matching lines @@
         return true;
     case GL_UNSIGNED_SHORT_5_6_5:
     case GL_UNSIGNED_SHORT_4_4_4_4:
     case GL_UNSIGNED_SHORT_5_5_5_1:
         if (buffer && buffer->type() != DOMArrayBufferView::TypeUint16) {
             synthesizeGLError(GL_INVALID_OPERATION, "readPixels", "type UNSIGNED_SHORT but ArrayBufferView not Uint16Array");
             return false;
         }
         return true;
     case GL_FLOAT:
-        if (extensionEnabled(OESTextureFloatName)) {
+        if (extensionEnabled(OESTextureFloatName) || extensionEnabled(OESTextureHalfFloatName)) {
             if (buffer && buffer->type() != DOMArrayBufferView::TypeFloat32) {
                 synthesizeGLError(GL_INVALID_OPERATION, "readPixels", "type FLOAT but ArrayBufferView not Float32Array");
                 return false;
             }
             return true;
         }
         synthesizeGLError(GL_INVALID_ENUM, "readPixels", "invalid type");
         return false;
     case GL_HALF_FLOAT_OES:
         if (extensionEnabled(OESTextureHalfFloatName)) {
@@ skipping 1559 matching lines @@
 {
     GLfloat value = 0;
     if (!isContextLost())
         contextGL()->GetFloatv(pname, &value);
     return WebGLAny(scriptState, value);
 }
 
 ScriptValue WebGLRenderingContextBase::getIntParameter(ScriptState* scriptState, GLenum pname)
 {
     GLint value = 0;
-    if (!isContextLost())
+    if (!isContextLost()) {
         contextGL()->GetIntegerv(pname, &value);
+        switch (pname) {
+        case GL_IMPLEMENTATION_COLOR_READ_FORMAT:
+        case GL_IMPLEMENTATION_COLOR_READ_TYPE:
+            if (value == 0) {
+                // This indicates read framebuffer is incomplete and an
+                // INVALID_OPERATION has been generated.
+                return ScriptValue::createNull(scriptState);
+            }
+            break;
+        default:
+            break;
+        }
+    }
     return WebGLAny(scriptState, value);
 }
 
 ScriptValue WebGLRenderingContextBase::getInt64Parameter(ScriptState* scriptState, GLenum pname)
 {
     GLint64 value = 0;
     if (!isContextLost())
         contextGL()->GetInteger64v(pname, &value);
     return WebGLAny(scriptState, value);
 }
@@ skipping 1115 matching lines @@
         contextGL()->PixelStorei(GL_UNPACK_ALIGNMENT, 1);
 }
 
 void WebGLRenderingContextBase::restoreUnpackParameters()
 {
     if (m_unpackAlignment != 1)
         contextGL()->PixelStorei(GL_UNPACK_ALIGNMENT, m_unpackAlignment);
 }
 
 } // namespace blink