Comment by io_eric

Thanks for the feedback! You're absolutely right to question this.

Just to clarify, my benchmark was using Canvas2D, not WebGL, that's why the numbers are much lower than your WebGL2 example. Based on your comment I actually removed the command batching to test the difference, and yeah, the batching optimization is smaller than I initially thought. WebCC with batched commands hits ~100 FPS, without batching it's ~86 FPS, and Emscripten is ~40 FPS. So the batching itself only contributes about ~14 FPS.

The bigger performance difference compared to Emscripten seems to come from how Canvas2D operations are handled. Emscripten uses their val class for JS interop which wraps each canvas call in their abstraction layer. WebCC writes raw commands (opcode + arguments) directly into a buffer that the JS side decodes with a tight switch statement. The JS decoder already has direct references to canvas objects and can call methods immediately without property lookups or wrapper overhead. With 10k draw calls per frame, these small per-call differences (property access, type boxing/unboxing, generic dispatch) compound significantly.