add accessibility_mods shader

misc/accessibility_mods.slang

@@ -0,0 +1,85 @@
+#version 450
+
+// Accessibility Mods
+// based on work by Karen Stevens for Electronic Arts
+// adapted for slang by hunterk
+
+layout(push_constant) uniform Push
+{
+	vec4 SourceSize;
+	vec4 OriginalSize;
+	vec4 OutputSize;
+	uint FrameCount;
+   float Protanopia, Deuteranopia, Tritanopia, D_factor, D_contrast, D_brightness;
+} params;
+
+#pragma parameter D_factor "Accessibility Adjustment Strength" 0.5 0.0 1.0 0.05
+#pragma parameter Protanopia "Protanopia Correction Toggle" 0.0 0.0 1.0 1.0
+#pragma parameter Deuteranopia "Deuteranopia Correction Toggle" 0.0 0.0 1.0 1.0
+#pragma parameter Tritanopia "Tritanopia Correction Toggle" 0.0 0.0 1.0 1.0
+#pragma parameter D_contrast "Contrast Adjustment" 0.0 0.0 1.0 0.05
+#pragma parameter D_brightness "Brightness Adjustment" 0.0 -1.0 1.0 0.05
+
+layout(std140, set = 0, binding = 0) uniform UBO
+{
+	mat4 MVP;
+} global;
+
+#define mul(a,b) b*a
+
+// RGB to LMS and back again
+// https://ssodelta.wordpress.com/tag/rgb-to-lms/
+mat3 RGBtoLMS = mat3( 17.8824,  43.5161,  4.1193,
+                       3.4557,  27.1554,  3.8671,
+                       0.02996,  0.18431, 1.4670);
+                       
+mat3 LMStoRGB = mat3( 0.0809, -0.1305,  0.1167,
+                     -0.0102,  0.0540, -0.1136,
+                     -0.0003, -0.0041,  0.6935);
+
+// This function draws heavily from Karen Stevens' Daltonization work, found here:
+// https://twvideo01.ubm-us.net/o1/vault/gdc2017/Presentations/Stevens_Karen_GameAccessibilityPracticalFixes.pdf
+vec3 Daltonize(vec3 input_col){
+   vec3 Dalton_col = input_col;
+   vec3 LMS_col = mul(input_col, RGBtoLMS);
+   Dalton_col.r = mix(LMS_col.r, (2.02344 * LMS_col.g) - (2.5281 * LMS_col.b), params.Protanopia);
+   Dalton_col.g = mix(LMS_col.g, (0.494207 * LMS_col.r) + (1.24827 * LMS_col.b), params.Deuteranopia);
+   Dalton_col.b = mix(LMS_col.b, (-0.395913 * LMS_col.r) + (0.801109 * LMS_col.g), params.Tritanopia);
+   
+   vec3 diff_col = input_col - mul(Dalton_col, LMStoRGB);
+
+   vec3 shift_col;
+   shift_col.r = 0.0;
+   shift_col.g = diff_col.g + diff_col.r;
+   shift_col.b = diff_col.b + diff_col.r;
+   
+   vec3 out_col = input_col + shift_col.rgb;
+   out_col = clamp(out_col, 0.0, 1.0);
+   
+   return out_col;
+}
+
+#pragma stage vertex
+layout(location = 0) in vec4 Position;
+layout(location = 1) in vec2 TexCoord;
+layout(location = 0) out vec2 vTexCoord;
+
+void main()
+{
+   gl_Position = global.MVP * Position;
+   vTexCoord = TexCoord;
+}
+
+#pragma stage fragment
+layout(location = 0) in vec2 vTexCoord;
+layout(location = 0) out vec4 FragColor;
+layout(set = 0, binding = 2) uniform sampler2D Source;
+
+void main()
+{
+   vec3 frame = texture(Source, vTexCoord).rgb;
+   frame = mix(frame, (((frame - 0.5) * (1.0 + params.D_contrast * 5.)) + 0.5), params.D_factor);
+   frame += params.D_brightness * params.D_factor;
+   vec3 Daltonized_frame = Daltonize(frame);
+   FragColor = vec4(mix(frame, Daltonized_frame, params.D_factor), 1.0);
+}