From a6305a1789befc3bca5dbd8955c2d1c8f1b6b0b0 Mon Sep 17 00:00:00 2001
From: metallic77 <43163462+metallic77@users.noreply.github.com>
Date: Sat, 13 May 2023 15:21:57 +0300
Subject: [PATCH] Update ega.slang (#426)

add CGA mode
---
 misc/shaders/ega.slang | 52 ++++++++++++++++++++++++++++++++++--------
 1 file changed, 42 insertions(+), 10 deletions(-)

diff --git a/misc/shaders/ega.slang b/misc/shaders/ega.slang
index 60d6e4e..14d5fe4 100644
--- a/misc/shaders/ega.slang
+++ b/misc/shaders/ega.slang
@@ -6,15 +6,21 @@ layout(push_constant) uniform Push
   vec4 OriginalSize;
   vec4 OutputSize;
   uint FrameCount;
-
+  float palette, color_enhance;
 } params;
 
+#pragma parameter palette "Choose palette Hercules/CGA/EGA" 2.0 0.0 2.0 1.0
+#define palette params.palette
+
+#pragma parameter color_enhance "Color Enchance" 1.4 1.0 4.0 0.05
+#define color_enhance params.color_enhance
+
 #define _ 0.0
 #define o (1./3.)
 #define b (2./3.)
 #define B 1.0
 
-#define color_enhance 1.0
+
 #define SourceSize params.SourceSize
 
 layout(std140, set = 0, binding = 0) uniform UBO
@@ -42,7 +48,10 @@ layout(set = 0, binding = 2) uniform sampler2D Source;
 // Color lookup table (RGBI palette with brown fix)
 const vec3 rgbi_palette[19] = 
 {
-  vec3(_, _, _),
+  vec3(_, _, _),   // cga
+  vec3(B, B, B),   // cga white
+  vec3(o, B, B),   // cga cyan
+  vec3(B, o, B),   // cga pink
   vec3(_, _, b),
   vec3(_, b, _),
   vec3(_, b, _),
@@ -56,11 +65,24 @@ const vec3 rgbi_palette[19] =
   vec3(o, o, o),
   vec3(o, o, B),
   vec3(o, B, o),
-  vec3(o, B, B),
   vec3(B, o, o),
-  vec3(B, o, B),
   vec3(B, B, o),
-  vec3(B, B, B),
+ 
+};
+
+const vec3 cga_palette[4] = 
+{
+  vec3(_, _, _),   // cga
+  vec3(o, B, B),   // cga cyan
+  vec3(B, o, B),   // cga pink
+  vec3(B, B, B),   // cga white
+};
+
+const vec3 simcga_palette[2] = 
+{
+  vec3(_, _, _),   // black
+  vec3(o, b, o),   // green
+
 };
 
 
@@ -80,7 +102,9 @@ vec3 nearest_rgbi (vec3 original)
   float dst;
   float min_dst = 2.0;
   int idx = 0;
-  for (int i=0; i<19; i++) 
+
+  int set; if (palette == 2.0)set = 19; else if (palette == 1.0) set = 4;else if (palette == 1.0) set = 2;
+  for (int i=0; i<set; i++) 
   {
     dst = distance(original, rgbi_palette[i]);
     if (dst < min_dst) 
@@ -89,7 +113,10 @@ vec3 nearest_rgbi (vec3 original)
       idx = i;
      }
   }
-  return rgbi_palette[idx];
+  if (palette == 2.0) return rgbi_palette[idx];
+  else if (palette == 1.0) return cga_palette[idx];
+  else if (palette == 0.0) return simcga_palette[idx];
+ 
 }
 
 
@@ -98,7 +125,7 @@ float modu(float x, float y)
 	return x - y * floor(x/y);
 }
 
-//fragment
+
 void main()
 {
   vec3 color = texture(Source, vTexCoord.xy).rgb;
@@ -128,5 +155,10 @@ void main()
       color *= 255.0;
       color += ohyes;
       color /= 255.0;
-  FragColor = vec4(nearest_rgbi(color*color_enhance), 1.0);
+     
+
+      vec3 final = nearest_rgbi(color*color_enhance);
+ 
+
+  FragColor = vec4(final, 1.0);
 }