automated snapshot

shaders/saturation.fs

@@ -0,0 +1,21 @@
+#version 330
+
+in vec2 fragTexCoord;
+in vec4 fragColor;
+
+uniform sampler2D texture0;
+uniform float uSat;   // 0 = grayscale, 1 = original, >1 = boosted
+
+out vec4 finalColor;
+
+void main() {
+    vec4 c = texture(texture0, fragTexCoord) * fragColor;
+
+    // luminance (perceptual-ish)
+    float l = dot(c.rgb, vec3(0.2126, 0.7152, 0.0722));
+    vec3 gray = vec3(l);
+
+    c.rgb = mix(gray, c.rgb, uSat);
+    finalColor = c; // preserves alpha
+}
+