distance(x,y) => length(x-y)

src/rewriter.fs

@@ -328,6 +328,11 @@ module private RewriterImpl =
             | _ -> failwithf "Cannot inline function %s because type-based disambiguation of user-defined function overloading is not supported" v.Name
 
         | FunCall(Op _, _) as op -> simplifyOperator env op
+
+        | FunCall(Var dist, [arg1; arg2]) when dist.Name = "distance" ->
+            let len = Ident("length", dist.Loc.line, dist.Loc.col)
+            FunCall(Var len, [FunCall (Op "-", [arg1; arg2])])
+
         | FunCall(Var constr, args) when constr.Name = "vec2" || constr.Name = "vec3" || constr.Name = "vec4" ->
             simplifyVec constr args
 

tests/compression_results.log

@@ -1,13 +1,13 @@
 clod.frag...                              8760 => 1486.187
-mouton/mouton.vert...                    16740 => 2404.493
+mouton/mouton.vert...                    16738 => 2401.196
 audio-flight-v2.frag                      4486 =>  878.312
 buoy.frag                                 4013 =>  606.290
 controllable-machinery.frag               7683 => 1225.947
 ed-209.frag                               7672 => 1338.529
 elevated.hlsl                             3401 =>  602.542
 endeavour.frag                            2568 =>  529.992
-from-the-seas-to-the-stars.frag          14240 => 2285.909
-frozen-wasteland.frag                     4517 =>  813.441
+from-the-seas-to-the-stars.frag          14236 => 2285.862
+frozen-wasteland.frag                     4515 =>  804.894
 kinder_painter.frag                       2836 =>  442.689
 leizex.frag                               2252 =>  506.309
 lunaquatic.frag                           5222 => 1043.256
@@ -20,5 +20,5 @@ slisesix.frag                             4497 =>  890.639
 terrarium.frag                            3575 =>  747.116
 the_real_party_is_in_your_pocket.frag    11986 => 1774.550
 valley_ball.glsl                          4307 =>  881.820
-yx_long_way_from_home.frag                2938 =>  600.714
-Total: 133509 => 23334.181
+yx_long_way_from_home.frag                2936 =>  598.845
+Total: 133499 => 23320.420

tests/real/chocolux.expected

@@ -1,37 +1,37 @@
 // Generated with  (https://github.com/laurentlb/Shader_Minifier/)
 #ifndef CHOCOLUX_EXPECTED_
 # define CHOCOLUX_EXPECTED_
-# define VAR_resolution "d"
+# define VAR_resolution "k"
 # define VAR_time "v"
 
 const char *chocolux_frag =
- "uniform vec2 d;"
+ "uniform vec2 k;"
  "uniform float v;"
  "float s(vec3 d)"
  "{"
-   "return distance(d,vec3(cos(v)+sin(v*.2),.3,2.+cos(v*.5)*.5))*distance(d,vec3(-cos(v*.7),.3,2.+sin(v*.5)))*distance(d,vec3(-sin(v*.2)*.5,sin(v),2))*(cos(d.y)*cos(d.x)-.1-cos(d.z*7.+v*7.)*cos(d.x*3.)*cos(d.y*4.)*.1);"
+   "return length(d-vec3(cos(v)+sin(v*.2),.3,2.+cos(v*.5)*.5))*length(d-vec3(-cos(v*.7),.3,2.+sin(v*.5)))*length(d-vec3(-sin(v*.2)*.5,sin(v),2))*(cos(d.y)*cos(d.x)-.1-cos(d.z*7.+v*7.)*cos(d.x*3.)*cos(d.y*4.)*.1);"
  "}"
  "void main()"
  "{"
-   "vec2 c=-1.+2.*gl_FragCoord.xy/d.xy;"
-   "vec3 i=vec3(c.x,c.y*1.25-.3,0),y=vec3(c.x+cos(v)*.3,c.y,1)/64.;"
+   "vec2 d=-1.+2.*gl_FragCoord.xy/k.xy;"
+   "vec3 c=vec3(d.x,d.y*1.25-.3,0),y=vec3(d.x+cos(v)*.3,d.y,1)/64.;"
    "vec4 f=vec4(0);"
    "float x=0.;"
    "for(int v=0;v<75;v++)"
      "{"
-       "if(s(i+y*x)<.4)"
+       "if(s(c+y*x)<.4)"
          "{"
            "x-=5.;"
            "for(int f=0;f<5;f++)"
              "{"
-               "if(s(i+y*x)<.4)"
+               "if(s(c+y*x)<.4)"
                  "break;"
                "x+=1.;"
              "}"
            "vec3 d=vec3(.01,0,0),v=vec3(0);"
-           "v.x=s(i+y*x)-s(vec3(i+y*x+d.xyy));"
-           "v.y=s(i+y*x)-s(vec3(i+y*x+d.yxy));"
-           "v.z=s(i+y*x)-s(vec3(i+y*x+d.yyx));"
+           "v.x=s(c+y*x)-s(vec3(c+y*x+d.xyy));"
+           "v.y=s(c+y*x)-s(vec3(c+y*x+d.yxy));"
+           "v.z=s(c+y*x)-s(vec3(c+y*x+d.yyx));"
            "v=normalize(v);"
            "f+=max(dot(vec3(0,0,-.5),v),0.)+max(dot(vec3(0,-.5,.5),v),0.)*.5;"
            "break;"

tests/real/from-the-seas-to-the-stars.frag.expected

@@ -636,7 +636,7 @@ void main()
                     col=vec3(.3,1,.3)/7.*clamp(p.y+1.,0,1);
                     col=mix(col,vec3(1),length(op.xz)-.12)/4;
                     p.y-=.8;
-                    p.xz+=normalize(p.xz-fp.xz)*(1.-smoothstep(0.,4.,distance(p.xz,fp.xz)))*pow(max(0.,p.y+.5),2.)*.3;
+                    p.xz+=normalize(p.xz-fp.xz)*(1.-smoothstep(0.,4.,length(p.xz-fp.xz)))*pow(max(0.,p.y+.5),2.)*.3;
                     w.x=R();
                     col+=pow(w.x,32.)*vec3(1,1,.5)/3.;
                     if(p.y<-1)
@@ -819,7 +819,7 @@ void main()
           vec3 bg=vec3(.02)*vec3(.7,.9,1)*.6;
           if(time>=200)
             bg*=max(0.,1.-(time-200)/7.);
-          c.xyz=mix(bg,c.xyz,c.w)*3*(1.-smoothstep(.2,1.,distance(vec2(coord),vec2(640,360))/880.));
+          c.xyz=mix(bg,c.xyz,c.w)*3*(1.-smoothstep(.2,1.,length(vec2(coord)-vec2(640,360))/880.));
           c*=min(1.,time/20.)*smoothstep(0.,3.,abs(time-60-18.5))*smoothstep(0.,1.,abs(time-61))*smoothstep(0.,1.,abs(time-148))*smoothstep(0.,1.,abs(time-165));
           if(time<43)
             c*=1.-smoothstep(42,43,time);

tests/real/frozen-wasteland.frag.expected

@@ -249,7 +249,7 @@ void mainImage(out vec4 fragColor,vec2 fragCoord)
   if(rz<FAR)
     {
       vec3 pos=ro+rz*rightdir,nor=normal(pos,rz);
-      float d=distance(pos,ro);
+      float d=length(pos-ro);
       nor=bump(pos,nor,d);
       float shd=shadow(pos,eyedir),dif=clamp(dot(nor,eyedir),0.,1.);
       vec3 ref=reflect(rightdir,nor);