From a26673163f2e08c9876886efdaf82fb501ce4fba Mon Sep 17 00:00:00 2001
From: myownfriend <obiwankenobi23@live.com>
Date: Tue, 20 May 2014 23:39:48 -0400
Subject: [PATCH] Update asciiart.glsl

---
 Data/Sys/Shaders/asciiart.glsl | 157 +++++++++++++++++----------------
 1 file changed, 81 insertions(+), 76 deletions(-)

diff --git a/Data/Sys/Shaders/asciiart.glsl b/Data/Sys/Shaders/asciiart.glsl
index d8cfbb4c0d..3a04cf0e1d 100644
--- a/Data/Sys/Shaders/asciiart.glsl
+++ b/Data/Sys/Shaders/asciiart.glsl
@@ -1,4 +1,5 @@
-uniform sampler2D samp8; // textures
+// textures
+uniform sampler2D samp8;
 uniform sampler2D samp9;
 
 const int char_width = 8;
@@ -15,81 +16,85 @@ uniform vec4 resolution;
 
 void main()
 {
-  vec2 char_pos = floor(uv0*resolution.xy/char_dim);
-  vec2 pixel_offset = floor(uv0*resolution.xy) - char_pos*char_dim;
+	vec2 char_pos = floor(uv0*resolution.xy/char_dim);
+	vec2 pixel_offset = floor(uv0*resolution.xy) - char_pos*char_dim;
 
-  float mindiff = float(char_width*char_height) * 100.0; // just a big number
-  float minc = 0.0;
-  vec4 mina = vec4(0.0, 0.0, 0.0, 0.0);
-  vec4 minb = vec4(0.0, 0.0, 0.0, 0.0);
-  
-  for(int i=0; i<char_count; i++) {
-    vec4 ff = vec4(0.0, 0.0, 0.0, 0.0);
-    vec4 f = vec4(0.0, 0.0, 0.0, 0.0);
-    vec4 ft = vec4(0.0, 0.0, 0.0, 0.0);
-    vec4 t = vec4(0.0, 0.0, 0.0, 0.0);
-    vec4 tt = vec4(0.0, 0.0, 0.0, 0.0);
-    
-    for(int x=0; x<char_width; x++) {
-      for(int y=0; y<char_height; y++) {
-      
-	vec2 tex_pos = char_pos*char_dim + vec2(x,y) + 0.5;
-	vec4 tex = texture(samp9, tex_pos * resolution.zw);
-      
-	vec2 font_pos = vec2(x+i*char_width, y) + 0.5;
-	vec4 font = texture(samp8, font_pos * font_scale);
-	
-	// generates sum of texture and font and their squares
-	ff += font*font;
-	f += font;
-	ft += font*tex;
-	t += tex;
-	tt += tex*tex;
-      }
-    }
-    
-    /*
-      The next lines are a bit harder, hf :-)
-      
-      The idea is to find the perfect char with the perfect background color and the perfect font color.
-      As this is an equation with three unknowns, we can't just try all chars and color combinations.
-      
-      As criterion how "perfect" the selection is, we compare the "mean squared error" of the resulted colors of all chars.
-      So, now the big issue: how to calculate the MSE without knowing the two colors ...
-      
-      In the next steps, "a" is the font color, "b" is the background color, "f" is the font value at this pixel, "t" is the texture value
-      
-      So the square error of one pixel is: 
-        e = ( t - a⋅f - b⋅(1-f) ) ^ 2
-        
-      In longer:
-        e = a^2⋅f^2 - 2⋅a⋅b⋅f^2 + 2⋅a⋅b⋅f - 2⋅a⋅f⋅t + b^2⋅f^2 - 2⋅b^2⋅f + b^2 + 2⋅b⋅f⋅t - 2⋅b⋅t + t^2
-        
-      The sum of all errors is: (as shortcut, ff,f,ft,t,tt are now the sums like declared above, sum(1) is the count of pixels)
-        sum(e) = a^2⋅ff - 2⋅a^2⋅ff + 2⋅a⋅b⋅f - 2⋅a⋅ft + b^2⋅ff - 2⋅b^2⋅f + b^2⋅sum(1) + 2⋅b⋅ft - 2⋅b⋅t + tt
-        
-      To find the minimum, we have to derive this by "a" and "b":
-        d/da sum(e) = 2⋅a⋅ff + 2⋅b⋅f - 2⋅b⋅ff - 2⋅ft
-        d/db sum(e) = 2⋅a⋅f - 2⋅a⋅ff - 4⋅b⋅f + 2⋅b⋅ff + 2⋅b⋅sum(1) + 2⋅ft - 2⋅t
-      
-      So, both equations must be zero at minimum and there is only one solution.
-    */
-    vec4 a = (f*ft - ff*t + f*t - ft*float(char_pixels)) / (f*f  - ff*float(char_pixels));
-    vec4 b = (f*ft - ff*t)                        / (f*f  - ff*float(char_pixels));
-    
-    vec4 diff = a*a*ff + 2.0*a*b*f - 2.0*a*b*ff - 2.0*a*ft + b*b *(-2.0*f + ff + float(char_pixels)) + 2.0*b*ft - 2.0*b*t + tt;
-    float diff_f = dot(diff, vec4(1.0, 1.0, 1.0, 1.0));
-    
-    if(diff_f < mindiff) {
-      mindiff = diff_f;
-      minc = float(i);
-      mina = a;
-      minb = b;
-    }
-  }
-  
-  vec2 font_pos_res = vec2(minc * float(char_width), 0.0) + pixel_offset + 0.5;
+	// just a big number
+	float mindiff = float(char_width*char_height) * 100.0;
 
-  vec4 col = texture(samp8, font_pos_res * font_scale);
-  ocol0 = mina * col + minb * (vec4(1.0,1.0,1.0,1.0) - col);
+	float minc = 0.0;
+	vec4 mina = vec4(0.0, 0.0, 0.0, 0.0);
+	vec4 minb = vec4(0.0, 0.0, 0.0, 0.0);
+
+	for(int i=0; i<char_count; i++)
+	{
+		vec4 ff = vec4(0.0, 0.0, 0.0, 0.0);
+		vec4 f = vec4(0.0, 0.0, 0.0, 0.0);
+		vec4 ft = vec4(0.0, 0.0, 0.0, 0.0);
+		vec4 t = vec4(0.0, 0.0, 0.0, 0.0);
+		vec4 tt = vec4(0.0, 0.0, 0.0, 0.0);
+
+		for(int x=0; x<char_width; x++)
+		{
+			for(int y=0; y<char_height; y++)
+			{
+				vec2 tex_pos = char_pos*char_dim + vec2(x,y) + 0.5;
+				vec4 tex = texture(samp9, tex_pos * resolution.zw);
+
+				vec2 font_pos = vec2(x+i*char_width, y) + 0.5;
+				vec4 font = texture(samp8, font_pos * font_scale);
+
+				// generates sum of texture and font and their squares
+				ff += font*font;
+				f += font;
+				ft += font*tex;
+				t += tex;
+				tt += tex*tex;
+			}
+		}
+
+		/*
+			The next lines are a bit harder, hf :-)
+
+			The idea is to find the perfect char with the perfect background color and the perfect font color.
+			As this is an equation with three unknowns, we can't just try all chars and color combinations.
+
+			As criterion how "perfect" the selection is, we compare the "mean squared error" of the resulted colors of all chars.
+			So, now the big issue: how to calculate the MSE without knowing the two colors ...
+
+			In the next steps, "a" is the font color, "b" is the background color, "f" is the font value at this pixel, "t" is the texture value
+
+			So the square error of one pixel is: 
+			e = ( t - a⋅f - b⋅(1-f) ) ^ 2
+
+			In longer:
+			e = a^2⋅f^2 - 2⋅a⋅b⋅f^2 + 2⋅a⋅b⋅f - 2⋅a⋅f⋅t + b^2⋅f^2 - 2⋅b^2⋅f + b^2 + 2⋅b⋅f⋅t - 2⋅b⋅t + t^2
+
+			The sum of all errors is: (as shortcut, ff,f,ft,t,tt are now the sums like declared above, sum(1) is the count of pixels)
+			sum(e) = a^2⋅ff - 2⋅a^2⋅ff + 2⋅a⋅b⋅f - 2⋅a⋅ft + b^2⋅ff - 2⋅b^2⋅f + b^2⋅sum(1) + 2⋅b⋅ft - 2⋅b⋅t + tt
+
+			To find the minimum, we have to derive this by "a" and "b":
+			d/da sum(e) = 2⋅a⋅ff + 2⋅b⋅f - 2⋅b⋅ff - 2⋅ft
+			d/db sum(e) = 2⋅a⋅f - 2⋅a⋅ff - 4⋅b⋅f + 2⋅b⋅ff + 2⋅b⋅sum(1) + 2⋅ft - 2⋅t
+
+			So, both equations must be zero at minimum and there is only one solution.
+		*/
+		vec4 a = (f*ft - ff*t + f*t - ft*float(char_pixels)) / (f*f  - ff*float(char_pixels));
+		vec4 b = (f*ft - ff*t) / (f*f  - ff*float(char_pixels));
+
+		vec4 diff = a*a*ff + 2.0*a*b*f - 2.0*a*b*ff - 2.0*a*ft + b*b *(-2.0*f + ff + float(char_pixels)) + 2.0*b*ft - 2.0*b*t + tt;
+		float diff_f = dot(diff, vec4(1.0, 1.0, 1.0, 1.0));
+
+		if(diff_f < mindiff) {
+			mindiff = diff_f;
+			minc = float(i);
+			mina = a;
+			minb = b;
+		}
+	}
+
+	vec2 font_pos_res = vec2(minc * float(char_width), 0.0) + pixel_offset + 0.5;
+
+	vec4 col = texture(samp8, font_pos_res * font_scale);
+	ocol0 = mina * col + minb * (vec4(1.0,1.0,1.0,1.0) - col);
 }