Bug 636002 - better messages about attrib index validation - r=jrmuizel, a=joe

content/canvas/src/WebGLContextValidate.cpp

@@ -376,6 +376,22 @@ PRBool WebGLContext::ValidateTexFormatAndType(WebGLenum format, WebGLenum type,
     }
 }
 
+PRBool WebGLContext::ValidateAttribIndex(WebGLuint index, const char *info)
+{
+    if (index > mAttribBuffers.Length()) {
+        if (index == WebGLuint(-1)) {
+             ErrorInvalidValue("%s: index -1 is invalid. That probably comes from a getAttribLication() call, "
+                               "where this return value -1 means that the passed name didn't correspond to an active attribute in "
+                               "the specified program.", info);
+        } else {
+             ErrorInvalidValue("%s: index %d is out of range", info, index);
+        }
+        return PR_FALSE;
+    } else {
+        return PR_TRUE;
+    }
+}
+
 PRBool
 WebGLContext::InitAndValidateGL()
 {