BloomGaussianWgsl.h

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#pragma once
namespace eve::graphics::shaders {
inline constexpr const char* kBloomGaussian = R"wgsl(
fn gaussian_linear(image:texture_2d<f32>,uv:vec2f)->vec3f {
 let size=vec2i(textureDimensions(image));let pos=uv*vec2f(size)-.5;let lo=vec2i(floor(pos));let f=fract(pos);
 var a=textureLoad(image,clamp(lo,vec2i(0),size-1),0).rgb;
 var b=textureLoad(image,clamp(lo+vec2i(1,0),vec2i(0),size-1),0).rgb;
 var c=textureLoad(image,clamp(lo+vec2i(0,1),vec2i(0),size-1),0).rgb;
 var d=textureLoad(image,clamp(lo+vec2i(1,1),vec2i(0),size-1),0).rgb;
 if(p(2)>5.5){
  a=select(vec3f(0),a,all(lo>=vec2i(0))&&all(lo<size));
  b=select(vec3f(0),b,all(lo+vec2i(1,0)>=vec2i(0))&&all(lo+vec2i(1,0)<size));
  c=select(vec3f(0),c,all(lo+vec2i(0,1)>=vec2i(0))&&all(lo+vec2i(0,1)<size));
  d=select(vec3f(0),d,all(lo+vec2i(1,1)>=vec2i(0))&&all(lo+vec2i(1,1)<size));
 }
 return mix(mix(a,b,f.x),mix(c,d,f.x),f.y);
}
fn gaussian_sample(uv:vec2f,h:vec2f)->vec3f{return gaussian_linear(mainTex,clamp(uv,.5*vec2f(p(0),p(1)),vec2f(1)-h));}
@fragment fn fs_main(i:FSIn)->@location(0) vec4f {
 let t=vec2f(p(0),p(1)); var c=vec3f(0);
 if(p(2)>4.5){
  if(p(2)<5.5){
   c=gaussian_linear(mainTex,i.uv);
   if(p(10)<.5){
    c=max(vec3f(0),(gaussian_linear(mainTex,i.uv+t*vec2f(-1,-1))+
      gaussian_linear(mainTex,i.uv+t*vec2f(1,-1))+
      gaussian_linear(mainTex,i.uv+t*vec2f(-1,1))+
      gaussian_linear(mainTex,i.uv+t*vec2f(1,1)))*.25);
   }
   if(p(10)>.5){
    c=min(c,vec3f(p(4)));
    if(p(3)>0){
     let brightness=max(c.r,max(c.g,c.b));let knee=p(3)*.5;
     var soft=clamp(brightness-p(3)+knee,0,2*knee);soft=soft*soft/(4*knee+.0001);
     c=max(c*(max(brightness-p(3),soft)/max(brightness,.0001)),vec3f(0));
    }
   }
  }
  else{
   let radius=max(p(7),.0001);var sum:f32=0;let count=i32(ceil(radius));
   let axis=select(vec2f(0,t.y),vec2f(t.x,0),p(2)<6.5);
   for(var j:i32=-count;j<=count;j++){
    let dx=f32(j)/radius;let weight=exp(-16.7*dx*dx);
    c+=gaussian_linear(mainTex,i.uv+axis*f32(j))*weight;sum+=weight;
   }
   c/=sum;
   if(p(2)>6.5){c*=p(8);if(p(9)>.5){c+=gaussian_linear(auxTex,i.uv);}}
  }
 }else if(p(2)<.5){
  c=min(gaussian_sample(i.uv,t*.5),vec3f(p(4)));
  let brightness=max(c.r,max(c.g,c.b));let knee=p(3)*.5;
  var soft=clamp(brightness-p(3)+knee,0,2*knee);soft=soft*soft/(4*knee+.0001);
  c=max(c*(max(brightness-p(3),soft)/max(brightness,.0001)),vec3f(0));
 }else if(p(2)<1.5){
  let weights=array<f32,5>(.22702703,.19459459,.12162162,.05405405,.01621622);
  for(var j:i32=-4;j<=4;j++){c+=gaussian_sample(i.uv+vec2f(f32(j)*2*t.x,0),t)*weights[abs(j)];}
 }else if(p(2)<2.5){
  c=gaussian_sample(i.uv,t*.5)*.22702703;
  c+=(gaussian_sample(i.uv+vec2f(0,1.38461538*t.y),t*.5)+gaussian_sample(i.uv-vec2f(0,1.38461538*t.y),t*.5))*.31621622;
  c+=(gaussian_sample(i.uv+vec2f(0,3.23076923*t.y),t*.5)+gaussian_sample(i.uv-vec2f(0,3.23076923*t.y),t*.5))*.07027027;
 }else{
  let h=.5/vec2f(textureDimensions(auxTex));
  let high=gaussian_sample(i.uv,t*.5);let low=gaussian_linear(auxTex,clamp(i.uv,h,vec2f(1)-h));
  c=select(high+low*p(6),mix(high,low,p(5)),p(2)<3.5);
 }
 return vec4f(c*i.color.rgb,1);
}
)wgsl";
}  // namespace eve::graphics::shaders