fized xna shader compatability with copious static consts

Effects/AvaliRecolor.fx

@@ -30,25 +30,23 @@ float4 hsv2rgb(float4 c) {
 
 DECLARE_TEXTURE(sprite, 0);  // The sprite texture
 
+// All of the uniform rgb and hsv colors don't have premultipled alpha!
+// We need to multiply the alpha in by hand.
 uniform float recolor1_threshold;
 uniform float4 recolor1_rgb_from;
 uniform float4 recolor1_rgb_to;
 
 uniform float rehue1_threshold;
 uniform float4 rehue1_threshold_mul;
-uniform float4 rehue1_rgb_from;
-uniform float4 rehue1_rgb_to;
+uniform float4 rehue1_hsv_from;
+uniform float4 rehue1_hsv_to;
 static const float rehue1_threshold_norm = rehue1_threshold * length(rehue1_threshold_mul);
-static const float4 rehue1_hsv_from = rgb2hsv(rehue1_rgb_from);
-static const float4 rehue1_hsv_to = rgb2hsv(rehue1_rgb_to);
 
 uniform float rehue2_threshold;
 uniform float4 rehue2_threshold_mul;
-uniform float4 rehue2_rgb_from;
-uniform float4 rehue2_rgb_to;
+uniform float4 rehue2_hsv_from;
+uniform float4 rehue2_hsv_to;
 static const float rehue2_threshold_norm = rehue2_threshold * length(rehue2_threshold_mul);
-static const float4 rehue2_hsv_from = rgb2hsv(rehue2_rgb_from);
-static const float4 rehue2_hsv_to = rgb2hsv(rehue2_rgb_to);
 
 
 float4 hueshift(
@@ -59,24 +57,33 @@ float4 hueshift(
   return hsv2rgb(hsv_clamp);
 }
 
+float4 multiplya(float4 color) {
+  return color * float4(color.aaa, 1.0);
+}
 
-float4 ps_main(float4 pos: SV_Position, float4 sprite_color: COLOR0, float2 uv: TEXCOORD0): COLOR {
+
+float4 ps_main(
+  float4 pos: SV_Position, float4 sprite_color: COLOR0, float2 uv: TEXCOORD0
+): COLOR {
   float4 tex_rgb = SAMPLE_TEXTURE(sprite, uv);
   float4 tex_hsv = rgb2hsv(tex_rgb);
 
   // replace recolor1_rgb_from with recolor1_rgb_to if in threshold
   if (distance(tex_rgb, recolor1_rgb_from) < recolor1_threshold) {
-    return recolor1_rgb_to * sprite_color;
+    // Multiply the alpha in because our colors are not premultiplied
+    return multiplya(recolor1_rgb_to) * sprite_color;
   }
 
   // hue-shift tex_hsv by the difference between rehue1_hsv_to - rehue1_hsv_from,
   // only if it is in threshold scaled by the threshold multipler
   if (distance(tex_hsv * rehue1_threshold_mul, rehue1_hsv_from * rehue1_threshold_mul) < rehue1_threshold_norm) {
-    return hueshift(tex_hsv, rehue1_hsv_from, rehue1_hsv_to) * sprite_color;
+    return multiplya(hueshift(tex_hsv, rehue1_hsv_from, rehue1_hsv_to))
+      * sprite_color;
   }
 
   if (distance(tex_hsv * rehue2_threshold_mul, rehue2_hsv_from * rehue2_threshold_mul) < rehue2_threshold_norm) {
-    return hueshift(tex_hsv, rehue2_hsv_from, rehue2_hsv_to) * sprite_color;
+    return multiplya(hueshift(tex_hsv, rehue2_hsv_from, rehue2_hsv_to))
+      * sprite_color;
   }
 
   return tex_rgb * sprite_color;

SourceCode/AvaliSkinModule.cs

@@ -202,24 +202,24 @@ namespace Celeste.Mod.AvaliSkin {
             // works at 0.12 minus the dark brown (actually works for real)
             FxRecolor.Parameters["rehue1_threshold"].SetValue(0.07f);
             FxRecolor.Parameters["rehue1_threshold_mul"].SetValue(
-                new Vector4(1f, 0.1f, 0.1f, 0f)
+                new Vector4(1f, 0.1f, 0.3f, 0f)
             );
-            FxRecolor.Parameters["rehue1_rgb_from"].SetValue(
-                (new Color((byte) 0xa2, 0x88, 0x5c, 0xff)).ToVector4()  // #a2885c
+            FxRecolor.Parameters["rehue1_hsv_from"].SetValue(
+                (new Color((byte) 0xa2, 0x88, 0x5c, 0xff)).ToHSV()  // #a2885c
+            );
+            FxRecolor.Parameters["rehue1_hsv_to"].SetValue(
+                lightColor2.ToHSV()
             );
-            FxRecolor.Parameters["rehue1_rgb_to"].SetValue(
-                lightColor2.ToVector4()
-            );  // #433722
 
             FxRecolor.Parameters["rehue2_threshold"].SetValue(0.07f);
             FxRecolor.Parameters["rehue2_threshold_mul"].SetValue(
                 new Vector4(1f, .8f, .8f, 0f)
             );
-            FxRecolor.Parameters["rehue2_rgb_from"].SetValue(
-                (new Color((byte) 0x4e, 0x4e, 0x4e, 0xff)).ToVector4()  // #4e4e4e
+            FxRecolor.Parameters["rehue2_hsv_from"].SetValue(
+                (new Color((byte) 0x4e, 0x4e, 0x4e, 0xff)).ToHSV()  // #4e4e4e
             );
-            FxRecolor.Parameters["rehue2_rgb_to"].SetValue(
-                darkColor2.ToVector4()
+            FxRecolor.Parameters["rehue2_hsv_to"].SetValue(
+                darkColor2.ToHSV()
             );
 
             FxRecolor.CurrentTechnique = FxRecolor.Techniques["Recolor"];

SourceCode/Misc.cs

@@ -1,4 +1,5 @@
 using System;
+using System.Threading;
 using System.Collections.Generic;
 using Microsoft.Xna.Framework;
 
@@ -75,6 +76,33 @@ namespace Celeste.Mod.AvaliSkin {
         public static Color Premultiply(this Color color) {
             return Color.FromNonPremultiplied(color.ToVector4());
         }
+
+        // From https://web.archive.org/web/20200213094821/http://lolengine.net/blog/2013/01/13/fast-rgb-to-hsv
+        public static Vector4 ToHSV(this Color color) {
+            // custom deconstructors are broken on mono
+            float r = color.R / 255.0f;
+            float g = color.G / 255.0f;
+            float b = color.B / 255.0f;
+            float a = color.A / 255.0f;
+
+            float K = 0f;
+
+            if (g < b) {
+                b = Interlocked.Exchange(ref g, b);
+                K = -1f;
+            }
+
+            if (r < g) {
+                g = Interlocked.Exchange(ref r, g);
+                K = -2f / 6f - K;
+            }
+
+            float chroma = r - Math.Min(g, b);
+            float h = Math.Abs(K + (g - b) / (6f * chroma + 1e-20f));
+            float s = chroma / (r + 1e-20f);
+            float v = r;
+
+            return new Vector4(h, s, v, a);
         }
     }
 }