bloom.gdshader

shader_type canvas_item;

uniform float bloomRadius = 1.0;
uniform float bloomThreshold = 1.0;
uniform float bloomIntensity = 1.0;

vec3 GetBloomPixel(sampler2D tex, vec2 uv, vec2 texPixelSize) {
  vec2 uv2 = floor(uv / texPixelSize) * texPixelSize;
  uv2 += texPixelSize * .001;
  vec3 tl = max(texture(tex, uv2).rgb - bloomThreshold, 0.0);
  vec3 tr = max(texture(tex, uv2 + vec2(texPixelSize.x, 0.0)).rgb - bloomThreshold, 0.0);
  vec3 bl = max(texture(tex, uv2 + vec2(0.0, texPixelSize.y)).rgb - bloomThreshold, 0.0);
  vec3 br = max(texture(tex, uv2 + vec2(texPixelSize.x, texPixelSize.y)).rgb - bloomThreshold, 0.0);
  vec2 f = fract( uv / texPixelSize );

  vec3 tA = mix( tl, tr, f.x );
  vec3 tB = mix( bl, br, f.x );

  return mix( tA, tB, f.y );
}

vec3 GetBloom(sampler2D tex, vec2 uv, vec2 texPixelSize) {
  vec3 bloom = vec3(0.0);
  vec2 off = vec2(1) * texPixelSize * bloomRadius;
  bloom += GetBloomPixel(tex, uv + off * vec2(-1, -1), texPixelSize * bloomRadius) * 0.292893;
  bloom += GetBloomPixel(tex, uv + off * vec2(-1, 0), texPixelSize * bloomRadius) * 0.5;
  bloom += GetBloomPixel(tex, uv + off * vec2(-1, 1), texPixelSize * bloomRadius) * 0.292893;
  bloom += GetBloomPixel(tex, uv + off * vec2(0, -1), texPixelSize * bloomRadius) * 0.5;
  bloom += GetBloomPixel(tex, uv + off * vec2(0, 0), texPixelSize * bloomRadius) * 1.0;
  bloom += GetBloomPixel(tex, uv + off * vec2(0, 1), texPixelSize * bloomRadius) * 0.5;
  bloom += GetBloomPixel(tex, uv + off * vec2(1, -1), texPixelSize * bloomRadius) * 0.292893;
  bloom += GetBloomPixel(tex, uv + off * vec2(1, 0), texPixelSize * bloomRadius) * 0.5;
  bloom += GetBloomPixel(tex, uv + off * vec2(1, 1), texPixelSize * bloomRadius) * 0.292893;
  bloom /= 4.171573f;
  return bloom;
}

void fragment() {
  vec4 col = texture(TEXTURE, UV);
//  vec3 bloom = GetBloom(TEXTURE, UV, TEXTURE_PIXEL_SIZE);
//  col.rgb += bloom * bloomIntensity;
col.r = 1.0;
col.a = 0.5;
  COLOR = col;
}