Make attrib missing buffer message clearer.

Source/core/html/canvas/WebGLRenderingContext.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 1775 matching lines @@
     state.enabled = false;
 
     // If the disabled index is the current maximum, trace backwards to find the new max enabled attrib index
     if (m_onePlusMaxEnabledAttribIndex == index + 1) {
         findNewMaxEnabledAttribIndex();
     }
 
     m_context->disableVertexAttribArray(index);
 }
 
-bool WebGLRenderingContext::validateRenderingState()
+bool WebGLRenderingContext::validateRenderingState(const char* functionName)
 {
-    if (!m_currentProgram)
+    if (!m_currentProgram) {
+        synthesizeGLError(GL_INVALID_OPERATION, functionName, "no valid shader program in use");
         return false;
+    }
 
     // Look in each enabled vertex attrib and check if they've been bound to a buffer.
     for (unsigned i = 0; i < m_onePlusMaxEnabledAttribIndex; ++i) {
         const WebGLVertexArrayObjectOES::VertexAttribState& state = m_boundVertexArrayObject->getVertexAttribState(i);
         if (state.enabled
-            && (!state.bufferBinding || !state.bufferBinding->object()))
+            && (!state.bufferBinding || !state.bufferBinding->object())) {
+            synthesizeGLError(GL_INVALID_OPERATION, functionName, String::format("attribute %d is enabled but has no buffer bound", i).utf8().data());
             return false;
+        }
     }
 
     return true;
 }
 
 bool WebGLRenderingContext::validateWebGLObject(const char* functionName, WebGLObject* object)
 {
     if (!object || !object->object()) {
         synthesizeGLError(GL_INVALID_VALUE, functionName, "no object or object deleted");
         return false;
@@ skipping 3395 matching lines @@
     if (first < 0 || count < 0) {
         synthesizeGLError(GL_INVALID_VALUE, functionName, "first or count < 0");
         return false;
     }
 
     if (!count) {
         markContextChanged();
         return false;
     }
 
-    if (!validateRenderingState()) {
-        synthesizeGLError(GL_INVALID_OPERATION, functionName, "attribs not setup correctly");
+    if (!validateRenderingState(functionName)) {
         return false;
     }
 
     const char* reason = "framebuffer incomplete";
     if (m_framebufferBinding && !m_framebufferBinding->onAccess(graphicsContext3D(), &reason)) {
         synthesizeGLError(GL_INVALID_FRAMEBUFFER_OPERATION, functionName, reason);
         return false;
     }
 
     return true;
@@ skipping 29 matching lines @@
     if (!count) {
         markContextChanged();
         return false;
     }
 
     if (!m_boundVertexArrayObject->boundElementArrayBuffer()) {
         synthesizeGLError(GL_INVALID_OPERATION, functionName, "no ELEMENT_ARRAY_BUFFER bound");
         return false;
     }
 
-    if (!validateRenderingState()) {
-        synthesizeGLError(GL_INVALID_OPERATION, functionName, "attribs not setup correctly");
+    if (!validateRenderingState(functionName)) {
         return false;
     }
 
     const char* reason = "framebuffer incomplete";
     if (m_framebufferBinding && !m_framebufferBinding->onAccess(graphicsContext3D(), &reason)) {
         synthesizeGLError(GL_INVALID_FRAMEBUFFER_OPERATION, functionName, reason);
         return false;
     }
 
     return true;
@@ skipping 354 matching lines @@
         if (m_textureUnits[i].m_texture2DBinding
             || m_textureUnits[i].m_textureCubeMapBinding) {
             m_onePlusMaxNonDefaultTextureUnit = i + 1;
             return;
         }
     }
     m_onePlusMaxNonDefaultTextureUnit = 0;
 }
 
 } // namespace WebCore