adding gfx and ui stuff

gfx/Color.c

@@ -0,0 +1,42 @@
+#include "math.h"
+#include "Color.h"
+
+real32 hueToRGB(real32 p, real32 q, real32 t) {
+    if (t < 0) {
+        t += 1;
+    } else if (t > 1) {
+        t -= 1;
+    }
+    if (t < 1.0f / 6) return p + (q - p) * 6 * t;
+    if (t < 1.0f / 2) return q;
+    if (t < 2.0f / 3) return p + (q - p) * (2.0f / 3 - t) * 6;
+    return p;
+};
+
+Vec4 hslToHex(real32 h, real32 s, real32 l) {
+    h /= 360;
+    s /= 100;
+    l /= 100;
+    real32 r, g, b;
+    if (s == 0) {
+        r = g = b = l;
+    } else {
+        real32 q = l < 0.5f ? l * (1 + s) : l + s - l * s;
+        real32 p = 2 * l - q;
+        r = hueToRGB(p, q, h + 1.0f / 3);
+        g = hueToRGB(p, q, h);
+        b = hueToRGB(p, q, h - 1.0f / 3);
+    }
+    return (Vec4){r, g, b, 1};
+}
+
+Vec4 colorFromIndex(int index) {
+    real32 color_wheel_cycle = floorf(index / 6.0f);
+    real32 darkness_cycle = floorf(index / 12.0f);
+    real32 spacing = (360.0f / 6.0f);
+    real32 offset = color_wheel_cycle == 0 ? 0 : spacing / (color_wheel_cycle + 2);
+    real32 hue = spacing * (index % 6) + offset;
+    real32 saturation = 100.0f;
+    real32 lightness = 1.0f / (2 + darkness_cycle) * 100;
+    return hslToHex(hue, saturation, lightness);
+}