many optimizations

shaders/diff.frag

@@ -0,0 +1,46 @@
+#version 330 core
+// Or appropriate GLSL version
+
+out vec4 FragColor;
+
+in vec2 TexCoords; // Comes from passthrough.vert
+
+uniform sampler2D texBefore;
+uniform sampler2D texAfter;
+
+uniform float diffBoost = 5.0; // Uniform to control contrast boost
+
+// Basic Luma calculation (Rec.709)
+float Luma(vec3 color) {
+    return dot(color, vec3(0.2126, 0.7152, 0.0722));
+}
+
+void main() {
+    vec3 colorBefore = texture(texBefore, TexCoords).rgb;
+    vec3 colorAfter = texture(texAfter, TexCoords).rgb;
+
+    // Calculate absolute difference per channel
+    vec3 diff = abs(colorAfter - colorBefore);
+
+    // Calculate average difference or luma difference (luma might be better)
+    // float avgDiff = (diff.r + diff.g + diff.b) / 3.0;
+    float lumaDiff = abs(Luma(colorAfter) - Luma(colorBefore));
+
+    // Boost the difference for visibility and clamp
+    float boostedDiff = clamp(lumaDiff * diffBoost, 0.0, 1.0);
+
+    // Output as grayscale
+    FragColor = vec4(vec3(boostedDiff), 1.0);
+
+    // --- Alternative Visualizations ---
+    // // Simple Red highlight for changes:
+    // if (boostedDiff > 0.05) { // Threshold
+    //     FragColor = vec4(1.0, 0.0, 0.0, 1.0);
+    // } else {
+    //     FragColor = vec4(colorBefore, 1.0); // Show original where no change
+    // }
+
+    // // False color based on difference magnitude (example):
+    // vec3 diffColor = vec3(boostedDiff * 2.0, (1.0 - boostedDiff) * 2.0, 0.0); // Example: Red=High diff, Green=Low diff
+    // FragColor = vec4(clamp(diffColor, 0.0, 1.0), 1.0);
+}