第 44 课：Branch Divergence

我的解：从结果来看没有区别？

我的解

uniform float iTime;
uniform sampler2D iChannel0;
uniform sampler2D iChannel1;

varying vec2 vUv;

void main() {
  vec2 uv = vUv;

  vec4 result = texture(iChannel0, uv);
  result.a = 0.0;

  result.a = mix(result.a, 1.0,  uv.x < 0.1 || uv.x > 0.9);
  result.a = mix(result.a, 1.0, uv.y < 0.1 || uv.y > 0.9);
  result.a = mix(result.a, 1.0, texture(iChannel1, uv).r > 0.45);


  gl_FragColor = result;
}

复盘笔记

• 从结果来看没有区别？
• 原版用if写的，会引入一个概念叫 Divergence aka wrap split,
• <2025/09/16>