case GL_INVALID_ENUM: return "invalid enumerant";
case GL_INVALID_VALUE: return "invalid value";
case GL_INVALID_OPERATION: return "invalid operation";
+#ifndef GL_ES_VERSION_2_0
case GL_STACK_OVERFLOW: return "stack overflow";
case GL_STACK_UNDERFLOW: return "stack underflow";
+#endif
case GL_OUT_OF_MEMORY: return "out of memory";
case GL_TABLE_TOO_LARGE: return "table too large";
case GL_INVALID_FRAMEBUFFER_OPERATION: return "invalid framebuffer operation";