wiki: Add fall_and_rotate window-close custom shader example

1 files changed, 35 insertions, 1 deletions

diff --git a/wiki/examples/close_custom_shader.frag b/wiki/examples/close_custom_shader.frag
index 8a777b99..f45ec22e 100644
--- a/wiki/examples/close_custom_shader.frag
+++ b/wiki/examples/close_custom_shader.frag
@@ -105,9 +105,43 @@ vec4 default_close(vec3 coords_geo, vec3 size_geo) {
     return color;
 }
 
+// Example: make the window "fall down" with slight rotation.
+vec4 fall_and_rotate(vec3 coords_geo, vec3 size_geo) {
+    // For this shader, set animation curve to linear for best results.
+
+    // Simulate an accelerated fall: square the (linear) progress.
+    float progress = niri_clamped_progress * niri_clamped_progress;
+
+    // Get our rotation pivot point coordinates at the bottom center of the window.
+    vec2 coords = (coords_geo.xy - vec2(0.5, 1.0)) * size_geo.xy;
+
+    // Move the window down to simulate a fall.
+    coords.y -= progress * 200.0;
+
+    // Randomize rotation direction and maximum angle.
+    float random = (niri_random_seed - 0.5) / 2.0;
+    random = sign(random) - random;
+    float max_angle = 0.05 * random;
+
+    // Rotate the window around our pivot point.
+    float angle = progress * max_angle;
+    mat2 rotate = mat2(cos(angle), -sin(angle), sin(angle), cos(angle));
+    coords = rotate * coords;
+
+    // Transform the coordinates back.
+    coords_geo = vec3(coords / size_geo.xy + vec2(0.5, 1.0), 1.0);
+
+    // Sample the window texture.
+    vec3 coords_tex = niri_geo_to_tex * coords_geo;
+    vec4 color = texture2D(niri_tex, coords_tex.st);
+
+    // Multiply by alpha to fade out.
+    return color * (1.0 - niri_clamped_progress);
+}
+
 // This is the function that you must define.
 vec4 close_color(vec3 coords_geo, vec3 size_geo) {
     // You can pick one of the example functions or write your own.
-    return solid_gradient(coords_geo, size_geo);
+    return rotate_and_fall_down(coords_geo, size_geo);
 }