From 055e35257856a2254ba0055b98c355b7480da338 Mon Sep 17 00:00:00 2001
From: Laurent Le Brun <laurentlb@gmail.com>
Date: Sat, 31 Dec 2022 22:18:26 +0100
Subject: [PATCH] Simple vec when all arguments are equal

vec2(1,1)  =>  vec2(1)
---
 README.md                                             |  9 ++++++++-
 src/rewriter.fs                                       | 11 +++++++++++
 tests/real/from-the-seas-to-the-stars.frag.expected   |  4 ++--
 tests/real/leizex.expected                            |  2 +-
 tests/real/mandelbulb.expected                        |  4 ++--
 tests/real/ohanami.frag.expected                      |  2 +-
 tests/real/sult.expected                              |  2 +-
 .../the_real_party_is_in_your_pocket.frag.expected    |  8 ++++----
 tests/real/valley_ball.glsl.expected                  |  2 +-
 tests/real/yx_long_way_from_home.frag.expected        |  4 ++--
 tests/unit/vectors.frag.expected                      |  2 +-
 11 files changed, 34 insertions(+), 16 deletions(-)

diff --git a/README.md b/README.md
index 88a5c3c9..b3285971 100644
--- a/README.md
+++ b/README.md
@@ -480,18 +480,25 @@ stored the result of a computation), so be careful with it.
 
 ### Vector constructors
 
-Calls to `vec2`, `vec3`, and `vec4` can be simplified using swizzles.
+- Calls to `vec2`, `vec3`, and `vec4` can be simplified using swizzles.
+- Remove useless constructor, when the argument is already a vec using swizzles.
+- If all arguments are equal (but not function calls), use only one argument.
+- Replace floats with ints, as it is safe inside the vec constructors.
 
 Input:
 ```glsl
 vec4(v1.x, v1.z, v2.r, v2.t);
 vec2(v1.xx);
+vec2(1.2, 1.2);
+vec2(1.);
 ```
 
 Output:
 ```glsl
 vec4(v1.xz,v2.xy);
 v1.xx;
+vec2(1.2);
+vec2(1);
 ```
 
 <!--
diff --git a/src/rewriter.fs b/src/rewriter.fs
index 8a18cae7..b77c0d8e 100644
--- a/src/rewriter.fs
+++ b/src/rewriter.fs
@@ -196,7 +196,18 @@ let private simplifyVec constr args =
         | Float (f, _) when Decimal.Round(f) = f -> Int (int f, "")
         | e -> e
 
+    // vec3(1,1,1)  =>  vec3(1)
+    // For safety, do not merge if there are function calls, e.g. vec2(rand(), rand()).
+    // Iterate over the args as long as the arguments are equal.
+    let rec mergeAllEquals allArgs = function
+        | FunCall _ :: _ -> allArgs
+        | e1 :: e2 :: rest when Printer.exprToS e1 = Printer.exprToS e2 ->
+            mergeAllEquals allArgs (e2 :: rest)
+        | [e] -> [e]
+        | _ -> allArgs
+
     let args = combineSwizzles args |> List.map useInts
+    let args = mergeAllEquals args args
     match args with
     | [Dot (_, field) as arg] when field.Length > 1 && isFieldSwizzle field ->
         // vec3(v.xxy)  =>  v.xxy
diff --git a/tests/real/from-the-seas-to-the-stars.frag.expected b/tests/real/from-the-seas-to-the-stars.frag.expected
index c6715317..aa41c978 100644
--- a/tests/real/from-the-seas-to-the-stars.frag.expected
+++ b/tests/real/from-the-seas-to-the-stars.frag.expected
@@ -17,7 +17,7 @@ float s(vec2 p)
 float valnoise(vec2 p)
 {
   vec2 c=floor(p),f=smoothstep(0.,1.,fract(p));
-  return mix(mix(s(c+vec2(0,0)),s(c+vec2(1,0)),f.x),mix(s(c+vec2(0,1)),s(c+vec2(1,1)),f.x),f.y);
+  return mix(mix(s(c+vec2(0)),s(c+vec2(1,0)),f.x),mix(s(c+vec2(0,1)),s(c+vec2(1)),f.x),f.y);
 }
 float fbm(vec2 p)
 {
@@ -561,7 +561,7 @@ void main()
                     w.w=R();
                     if(w.w<.5)
                       {
-                        p=(w.xyz*2-1)*vec3(.1,.1,.1);
+                        p=(w.xyz*2-1)*vec3(.1);
                         vec3 op=p;
                         p.y-=.3;
                         p.xz*=mix(.1,.5*p.y*4.-1.,pow(fract(p.y*8.),4));
diff --git a/tests/real/leizex.expected b/tests/real/leizex.expected
index 73b4dc1c..41104220 100644
--- a/tests/real/leizex.expected
+++ b/tests/real/leizex.expected
@@ -23,7 +23,7 @@ _leizex_frag:
 	db '{'
 	db   'ivec3 ip=ivec3(floor(x));'
 	db   'vec3 f=fract(x);'
-	db   'vec2 dmin=vec2(1,1);'
+	db   'vec2 dmin=vec2(1);'
 	db   'for(int k=-1;k<=1;k++)'
 	db     'for(int j=-1;j<=1;j++)'
 	db       'for(int i=-1;i<=1;i++)'
diff --git a/tests/real/mandelbulb.expected b/tests/real/mandelbulb.expected
index 3f34b9e0..a08fb9a0 100644
--- a/tests/real/mandelbulb.expected
+++ b/tests/real/mandelbulb.expected
@@ -91,7 +91,7 @@ const char *mandelbulb_frag =
  "void main()"
  "{"
    "vec2 v=-1.+2.*gl_FragCoord.xy/resolution.xy,c=v*vec2(1.33,1);"
-   "vec3 x=vec3(.577,.577,.577),o=vec3(-.707,0,.707);"
+   "vec3 x=vec3(.577),o=vec3(-.707,0,.707);"
    "float y=1.,s=1.4+.2*cos(6.28318*time/20.);"
    "vec3 z=vec3(s*sin(6.28318*time/20.),.3-.4*sin(6.28318*time/20.),s*cos(6.28318*time/20.)),p=vec3(0,.1,0),m=normalize(p-z),t=vec3(0,1,0),r=normalize(cross(m,t)),w=normalize(cross(r,m)),e=normalize(c.x*r+c.y*w+1.5*m),l,i;"
    "vec4 u;"
@@ -111,7 +111,7 @@ const char *mandelbulb_frag =
        "if(d>.001)"
          "if(f(n,x,q,1e20,g,C,y))"
            "d=.1;"
-       "i=vec3(1,1,1);"
+       "i=vec3(1);"
        "i=mix(i,vec3(.8,.6,.2),sqrt(u.x)*1.25);"
        "i=mix(i,vec3(.8,.3,.3),sqrt(u.y)*1.25);"
        "i=mix(i,vec3(.7,.4,.3),sqrt(u.z)*1.25);"
diff --git a/tests/real/ohanami.frag.expected b/tests/real/ohanami.frag.expected
index 90aebff1..31b9b187 100644
--- a/tests/real/ohanami.frag.expected
+++ b/tests/real/ohanami.frag.expected
@@ -37,7 +37,7 @@ float noise(vec2 p)
 float valnoise(vec2 p)
 {
   vec2 c=floor(p),f=smoothstep(0.,1,fract(p));
-  return mix(mix(noise(c+vec2(0,0)),noise(c+vec2(1,0)),f.x),mix(noise(c+vec2(0,1)),noise(c+vec2(1,1)),f.x),f.y);
+  return mix(mix(noise(c+vec2(0)),noise(c+vec2(1,0)),f.x),mix(noise(c+vec2(0,1)),noise(c+vec2(1)),f.x),f.y);
 }
 vec4 samp(vec2 p)
 {
diff --git a/tests/real/sult.expected b/tests/real/sult.expected
index deb5a200..464692f2 100644
--- a/tests/real/sult.expected
+++ b/tests/real/sult.expected
@@ -8,7 +8,7 @@
 
 const char *sult_frag =
  "float v=5.,y=.9,a=0.,f=90.,e=0.;"
- "vec3 r=vec3(1,1,1),c=vec3(0,0,1),t=vec3(0,0,1.5);"
+ "vec3 r=vec3(1),c=vec3(0,0,1),t=vec3(0,0,1.5);"
  "uniform vec2 m;"
  "uniform float l;"
  "vec3 rotatey(vec3 v,float m)"
diff --git a/tests/real/the_real_party_is_in_your_pocket.frag.expected b/tests/real/the_real_party_is_in_your_pocket.frag.expected
index c6af978b..09585ada 100644
--- a/tests/real/the_real_party_is_in_your_pocket.frag.expected
+++ b/tests/real/the_real_party_is_in_your_pocket.frag.expected
@@ -66,7 +66,7 @@ const char *the_real_party_is_in_your_pocket_frag =
    "m.x-=.023;"
    "m.x=abs(m.x);"
    "m.x-=max(m.y/2.+.002,0.);"
-   "l=min(l,v(m-vec2(0,0),vec2(.0065,.028)));"
+   "l=min(l,v(m-vec2(0),vec2(.0065,.028)));"
    "return l;"
  "}"
  "float v(vec2 l)"
@@ -135,7 +135,7 @@ const char *the_real_party_is_in_your_pocket_frag =
        "a=m(a,min(l.z,-t+.004),320.);"
        "a=m(a,min(l.z,-min(1.,e)+.006),192.);"
        "l.xy-=vec2(.405,-.28);"
-       "float g=(1.-x(.002,min(min(n(l.xy,vec2(0,-.035),vec2(-.014,.024)),n(l.xy,vec2(-.03,-.035),vec2(-.014,.024))),n(l.xy,vec2(-.02,-.02),vec2(-.01,-.02)))-.0025))*.002;"
+       "float g=(1.-x(.002,min(min(n(l.xy,vec2(0,-.035),vec2(-.014,.024)),n(l.xy,vec2(-.03,-.035),vec2(-.014,.024))),n(l.xy,vec2(-.02),vec2(-.01,-.02)))-.0025))*.002;"
        "l.xy+=vec2(.405,-.28);"
        "l.xy-=vec2(.202,-.345);"
        "float w=min(min(min(n(l.xy,vec2(-.03,-.035),vec2(-.03,.024)),n(l.xy,vec2(-.03,-.035),vec2(-.018,-.035))),n(l.xy,vec2(-.03,.024),vec2(-.018,.024))),n(l.xy,vec2(-.03,-.0055),vec2(-.018,-.0055)));"
@@ -295,7 +295,7 @@ const char *the_real_party_is_in_your_pocket_frag =
                        "if(d.y>.5)"
                          "{"
                            "vec2 h=o.zw-vec2(-.38,.6);"
-                           "float g=min(min(min(min(min(min(max(length(h-vec2(.005,.005))-.0125,-(length(h-vec2(-.012,.005))-.025)),max(length(h-vec2(-.02,.005))-.0125,-(length(h-vec2(-.045,.005))-.03))),max(length(h-vec2(.005,.005))-.0125,-(length(h-vec2(-.012,.005))-.025))),max(length(h-vec2(.03,.005))-.0125,-(length(h-vec2(.02,.005))-.02))),abs(length(h-vec2(-.037,-.0398))-.0104)),n(h,vec2(-.064,-.05),vec2(-.064,-.03))),max(-h.x-.063,abs(length(vec2(max(0.,h.x+.06),h.y+.035))-.006)));"
+                           "float g=min(min(min(min(min(min(max(length(h-vec2(.005))-.0125,-(length(h-vec2(-.012,.005))-.025)),max(length(h-vec2(-.02,.005))-.0125,-(length(h-vec2(-.045,.005))-.03))),max(length(h-vec2(.005))-.0125,-(length(h-vec2(-.012,.005))-.025))),max(length(h-vec2(.03,.005))-.0125,-(length(h-vec2(.02,.005))-.02))),abs(length(h-vec2(-.037,-.0398))-.0104)),n(h,vec2(-.064,-.05),vec2(-.064,-.03))),max(-h.x-.063,abs(length(vec2(max(0.,h.x+.06),h.y+.035))-.006)));"
                            "h.x-=.091;"
                            "g=min(g,n(h,vec2(-.064,-.05),vec2(-.064,-.03)));"
                            "g=min(g,max(-h.x-.063,abs(length(vec2(max(0.,h.x+.06),h.y+.035))-.006)));"
@@ -338,7 +338,7 @@ const char *the_real_party_is_in_your_pocket_frag =
                              "t=mix(t,vec3(.730857,.454964,.000553633),step(abs(length(h)-.02)-.007,0.));"
                            "}"
                            "{"
-                             "vec2 h=o.zw-vec2(.24,.103),g=vec2(-.006,-.026),u=vec2(-.002,0),q=vec2(-.007,.016),C=q+normalize(q-u)*.012,F=vec2(.02,.02),T=C+normalize(F-C)*.05,Z=vec2(.002,-.007),Y=vec2(.025,-.028);"
+                             "vec2 h=o.zw-vec2(.24,.103),g=vec2(-.006,-.026),u=vec2(-.002,0),q=vec2(-.007,.016),C=q+normalize(q-u)*.012,F=vec2(.02),T=C+normalize(F-C)*.05,Z=vec2(.002,-.007),Y=vec2(.025,-.028);"
                              "t=mix(t,vec3(0,.332318,.292872),step(min(min(min(m(h,q,C,F),m(h,g,u,q)),m(h,F,T,Z)),m(h,Z,(Z+Y)/2.+vec2(.001),Y))-.007,0.));"
                            "}"
                          "}"
diff --git a/tests/real/valley_ball.glsl.expected b/tests/real/valley_ball.glsl.expected
index de320461..d7a52904 100644
--- a/tests/real/valley_ball.glsl.expected
+++ b/tests/real/valley_ball.glsl.expected
@@ -18,7 +18,7 @@ float smoothrnd(vec2 x)
   vec2 a=fract(x);
   x-=a;
   vec2 u=a*a*(3.-2.*a);
-  return mix(mix(rnd(x+vec2(0,0)),rnd(x+vec2(1,0)),u.x),mix(rnd(x+vec2(0,1)),rnd(x+vec2(1,1)),u.x),u.y);
+  return mix(mix(rnd(x+vec2(0)),rnd(x+vec2(1,0)),u.x),mix(rnd(x+vec2(0,1)),rnd(x+vec2(1)),u.x),u.y);
 }
 float norm(float x)
 {
diff --git a/tests/real/yx_long_way_from_home.frag.expected b/tests/real/yx_long_way_from_home.frag.expected
index 43cb96f7..9c9e51c8 100644
--- a/tests/real/yx_long_way_from_home.frag.expected
+++ b/tests/real/yx_long_way_from_home.frag.expected
@@ -73,7 +73,7 @@ const char *yx_long_way_from_home_frag =
  "vec2 i;"
  "vec3 h(vec3 v)"
  "{"
-   "vec3 i=cross(vec3(-1,-1,-1),v);"
+   "vec3 i=cross(vec3(-1),v);"
    "return i;"
  "}"
  "vec3 e(vec3 v,float y)"
@@ -174,7 +174,7 @@ const char *yx_long_way_from_home_frag =
    "i=s(x);"
    "v+=(i-.5)/iResolution.xy;"
    "v.x*=iResolution.x/iResolution.y;"
-   "const vec3 f=vec3(-4,2,3),y=vec3(0,0,0);"
+   "const vec3 f=vec3(-4,2,3),y=vec3(0);"
    "const float z=distance(f,y);"
    "const vec2 r=vec2(1,2)*.015;"
    "vec3 c=vec3(0),o=normalize(vec3(v,2));"
diff --git a/tests/unit/vectors.frag.expected b/tests/unit/vectors.frag.expected
index f727d3b1..515a6145 100644
--- a/tests/unit/vectors.frag.expected
+++ b/tests/unit/vectors.frag.expected
@@ -1,6 +1,6 @@
 float swizzles()
 {
-  vec2 v1=vec2(1,1);
+  vec2 v1=vec2(1);
   vec3 v2=v1.xyx,v3=vec3(v1.x,v2.xx);
   vec4 v4=v1.xxyx,v5=vec4(1,v2.zy,2),v6=vec4(v1.xy,v2.xy);
   return v1.x+v2.x+v3.x+v4.x+v5.x+v6.x;