.

PresenterConsole/assets/shader/ascii.shader

@@ -37,34 +37,50 @@ const vec3 ConsoleColorVec3[16] = vec3[](
     vec3(1.0, 1.0, 1.0)  // White
 );
 
-// RGB to LAB conversion (simplified approximation)
-vec3 rgb2lab(vec3 x) {
-    const float epsilon = 0.008856;
-    const float k = 903.3;
-    vec3 fx;
-    fx.x = x.x > epsilon ? pow(x.x, 1.0 / 3.0) : (k * x.x + 16.0) / 116.0;
-    fx.y = x.y > epsilon ? pow(x.y, 1.0 / 3.0) : (k * x.y + 16.0) / 116.0;
-    fx.z = x.z > epsilon ? pow(x.z, 1.0 / 3.0) : (k * x.z + 16.0) / 116.0;
-    return fx;
+vec3 srgbToLinear(vec3 color) {
+    return mix(color / 12.92, pow((color + 0.055) / 1.055, vec3(2.4)), step(0.04045, color));
+}
+
+vec3 rgbToXyz(vec3 color) {
+    const mat3 rgbToXyzMatrix = mat3(
+        0.4124564, 0.3575761, 0.1804375,
+        0.2126729, 0.7151522, 0.0721750,
+        0.0193339, 0.1191920, 0.9503041
+    );
+    return rgbToXyzMatrix * color;
+}
+
+vec3 xyzToLab(vec3 xyz) {
+    const vec3 whitePoint = vec3(0.95047, 1.0, 1.08883); // D65 white point
+    xyz = xyz / whitePoint;
+
+    vec3 f = mix(pow(xyz, vec3(1.0 / 3.0)), 7.787 * xyz + 16.0 / 116.0, step(0.008856, xyz));
+    return vec3(
+        (116.0 * f.y) - 16.0,
+        500.0 * (f.x - f.y),
+        200.0 * (f.y - f.z)
+    );
+}
+
+vec3 rgb2hsv(vec3 c)
+{
+    vec4 K = vec4(0.0, -1.0 / 3.0, 2.0 / 3.0, -1.0);
+    vec4 p = mix(vec4(c.bg, K.wz), vec4(c.gb, K.xy), step(c.b, c.g));
+    vec4 q = mix(vec4(p.xyw, c.r), vec4(c.r, p.yzx), step(p.x, c.r));
+
+    float d = q.x - min(q.w, q.y);
+    float e = 1.0e-10;
+    return vec3(abs(q.z + (q.w - q.y) / (6.0 * d + e)), d / (q.x + e), q.x);
 }
 
-// Perceptually weighted color difference (CIEDE2000-inspired)
 float perceptualColorDistance(vec3 color1, vec3 color2) {
-    vec3 lab1 = rgb2lab(color1);
-    vec3 lab2 = rgb2lab(color2);
+    vec3 lab1 = xyzToLab(rgbToXyz(srgbToLinear(color1)));
+    vec3 lab2 = xyzToLab(rgbToXyz(srgbToLinear(color2)));
+    vec3 delta = lab1 - lab2;
 
-    // Compute LAB-like color difference with perceptual weighting
-    float deltaL = lab1.x - lab2.x;
-    float deltaA = lab1.y - lab2.y;
-    float deltaB = lab1.z - lab2.z;
-
-    // Perceptual weighting
-    return deltaL * deltaL * 1.0 + // Lightness difference
-        deltaA * deltaA * 1.5 +    // Green-Red difference
-        deltaB * deltaB * 1.5;     // Blue-Yellow difference
+    return dot(delta, delta);
 }
 
-// Advanced color matching considering multiple color attributes
 int findMostPerceptuallyAccurateColor(vec3 color) {
     int bestMatchIndex = 0;
     float minDistance = perceptualColorDistance(color, ConsoleColorVec3[0]);