Scissor Test

A scissor rectangle limits which framebuffer pixels can be changed while it is enabled.

Program

The scissor test is a simple rectangular mask. It is useful for UI panes, partial clears, and region-limited rendering.

scissor_test.html

<canvas id="stage" width="360" height="210"></canvas>
<script>
  gl.enable(gl.SCISSOR_TEST);
  gl.scissor(48, 36, 264, 138);
  gl.clearColor(0.08, 0.72, 0.64, 1.0);
  gl.clear(gl.COLOR_BUFFER_BIT);
  gl.disable(gl.SCISSOR_TEST);
</script>

scissor test The scissor test rejects fragments and clear writes outside a rectangular pixel box.

partial clear A partial clear updates only a selected framebuffer region.