src/cobalt/renderer/glimp_shaders/glsl/fragment_skia_rect_blur.glsl

#version 100
precision mediump float;
uniform sampler2D uSampler0_Stage0;
uniform vec4 uproxyRect_Stage0;
uniform float uprofileSize_Stage0;
uniform float uRTHeight;
varying vec4 vColor;

void main() {
  vec4 fragCoordYDown =
      vec4(gl_FragCoord.x, uRTHeight - gl_FragCoord.y, 1.0, 1.0);
  vec4 output_Stage0;
  {
    // Stage 0: RectBlur
    vec4 src=vColor;
    vec2 translatedPos = fragCoordYDown.xy - uproxyRect_Stage0.xy;
    float width = uproxyRect_Stage0.z - uproxyRect_Stage0.x;
    float height = uproxyRect_Stage0.w - uproxyRect_Stage0.y;
    vec2 smallDims =
        vec2(width - uprofileSize_Stage0, height-uprofileSize_Stage0);
    float center = 2.0 * floor(uprofileSize_Stage0/2.0 + .25) - 1.0;
    vec2 wh = smallDims - vec2(center,center);
    float horiz_lookup;
    {
      float coord = (0.5 * (abs(2.0*translatedPos.x - width) - wh.x))/uprofileSize_Stage0;
      horiz_lookup = texture2D(uSampler0_Stage0, vec2(coord,0.5)).aaaa.a;
    }
    float vert_lookup;
    {
      float coord = (0.5 * (abs(2.0*translatedPos.y - height) - wh.y))/uprofileSize_Stage0;
      vert_lookup = texture2D(uSampler0_Stage0, vec2(coord,0.5)).aaaa.a;
    }
    float final = horiz_lookup * vert_lookup;
    output_Stage0 = src * vec4(final);
  }

  gl_FragColor = output_Stage0;
}