Refactor of luminance threshold logic (#495)

handheld/gb-dot-matrix-white.glslp

@@ -35,7 +35,7 @@ scale_y2 = "1.000000"
 
 
 textures = "COLOR_PALETTE;BACKGROUND"
-COLOR_PALETTE = shaders/gameboy/resources/sample-palettes/w-palette.png
+COLOR_PALETTE = shaders/gameboy/resources/sample-palettes/b-w-palette.png
 COLOR_PALETTE_linear = "false"
 COLOR_PALETTE_wrap_mode = "clamp_to_border"
 COLOR_PALETTE_mipmap = "false"

handheld/shaders/gameboy-dm-color/gb-pass0.glsl

@@ -144,6 +144,9 @@ COMPAT_VARYING vec4 TEX0;
 COMPAT_VARYING vec2 dot_size;
 COMPAT_VARYING vec2 one_texel;
 
+// compatibility #defines
+#define Source Texture
+#define vTexCoord TEX0.xy
 #define SourceSize vec4(TextureSize, 1.0 / TextureSize) //either TextureSize or InputSize
 #define outsize vec4(OutputSize, 1.0 / OutputSize)
 
@@ -155,12 +158,16 @@ uniform COMPAT_PRECISION float color_toggle;
 uniform COMPAT_PRECISION float negative_toggle;
 uniform COMPAT_PRECISION float desaturate_toggle;
 #endif
-  
+
+ 
+////////////////////////////////////////////////////////////////////////////////
+//fragment definitions                                                        //
+////////////////////////////////////////////////////////////////////////////////
+ 
 
 void main()
 {
     vec3 foreground_color = COMPAT_TEXTURE(COLOR_PALETTE, vec2(0.75, 0.5)).rgb;
-
     vec3 curr_rgb_original = COMPAT_TEXTURE(Texture, TEX0.xy).rgb;
     vec3 curr_rgb_negative = vec3(1.0) - curr_rgb_original;
     vec3 curr_rgb = mix(curr_rgb_original, curr_rgb_negative, step(0.5, negative_toggle));
@@ -170,29 +177,41 @@ void main()
         is_on_dot = 1.0;
 
     vec3 input_rgb = curr_rgb;
-    input_rgb += (texture2D(PrevTexture, TEX0.xy).rgb - input_rgb) * response_time;
-    input_rgb += (texture2D(Prev1Texture, TEX0.xy).rgb - input_rgb) * pow(response_time, 2.0);
-    input_rgb += (texture2D(Prev2Texture, TEX0.xy).rgb - input_rgb) * pow(response_time, 3.0);
-    input_rgb += (texture2D(Prev3Texture, TEX0.xy).rgb - input_rgb) * pow(response_time, 4.0);
-    input_rgb += (texture2D(Prev4Texture, TEX0.xy).rgb - input_rgb) * pow(response_time, 5.0);
-    input_rgb += (texture2D(Prev5Texture, TEX0.xy).rgb - input_rgb) * pow(response_time, 6.0);
-    input_rgb += (texture2D(Prev6Texture, TEX0.xy).rgb - input_rgb) * pow(response_time, 7.0);
 
+    // Apply response time smoothing with a decreasing impact of each previous frame
+    float base_factor = pow(response_time, 2.0); // Adjust the exponent for a smoother curve
+
+    input_rgb += (COMPAT_TEXTURE(PrevTexture, TEX0.xy).rgb - input_rgb) * response_time;
+    input_rgb += (COMPAT_TEXTURE(Prev1Texture, TEX0.xy).rgb - input_rgb) * base_factor * 0.5;
+    input_rgb += (COMPAT_TEXTURE(Prev2Texture, TEX0.xy).rgb - input_rgb) * base_factor * 0.25;
+    input_rgb += (COMPAT_TEXTURE(Prev3Texture, TEX0.xy).rgb - input_rgb) * base_factor * 0.125;
+    input_rgb += (COMPAT_TEXTURE(Prev4Texture, TEX0.xy).rgb - input_rgb) * base_factor * 0.0625;
+    input_rgb += (COMPAT_TEXTURE(Prev5Texture, TEX0.xy).rgb - input_rgb) * base_factor * 0.03125;
+    input_rgb += (COMPAT_TEXTURE(Prev6Texture, TEX0.xy).rgb - input_rgb) * base_factor * 0.015625;
+
+    // Calculate the alpha based on the weighted input RGB
     float rgb_to_alpha = (input_rgb.r + input_rgb.g + input_rgb.b) / 3.0 + (is_on_dot * baseline_alpha);
-    
+
+    // Apply color toggle and mix the input color with the foreground color
     vec3 final_color = mix(input_rgb, foreground_color, color_toggle);
 
-    // luminance calculation
+    // Luminance calculation for desaturation
     float luminance = dot(final_color, vec3(0.299, 0.587, 0.114));
-    final_color = mix(final_color, vec3(luminance), desaturate_toggle); // Mix color
+    final_color = mix(final_color, vec3(luminance), desaturate_toggle);
 
-    vec4 out_color = vec4(final_color, rgb_to_alpha);  
+    vec4 out_color = vec4(final_color, rgb_to_alpha);
 
+// Determine if all elements should be considered as "on dot" based on color_toggle
+if (color_toggle > 0.5) {
+    out_color.a *= is_on_dot; // Treat all pixels as "on dot"
+} else {
+    // Adjust alpha transparency based on luminance threshold
     if (dot(input_rgb, vec3(0.299, 0.587, 0.114)) > 0.85) {
-        out_color.a = 1.0;
+        out_color.a = 1.0; // Fully opaque if luminance is high enough
     } else {
-        out_color.a *= is_on_dot;
+        out_color.a *= is_on_dot; // Only apply dot masking if necessary
     }
+}
 
     gl_FragColor = out_color;
 }