cocos-creator-template/assets/chunks/builtin/internal/embedded-alpha.chunk

// Copyright (c) 2017-2020 Xiamen Yaji Software Co., Ltd.

vec4 CCSampleWithAlphaSeparated(sampler2D tex, vec2 uv) {
#if CC_USE_EMBEDDED_ALPHA
  return vec4(texture(tex, uv).rgb, texture(tex, uv + vec2(0.0, 0.5)).r);
#else
  return texture(tex, uv);
#endif
}