Change custom-shader to a prelude-epilogue system

1 files changed, 7 insertions, 15 deletions

diff --git a/wiki/Configuration:-Animations.md b/wiki/Configuration:-Animations.md
index 8c933fdd..440d10fa 100644
--- a/wiki/Configuration:-Animations.md
+++ b/wiki/Configuration:-Animations.md
@@ -234,31 +234,23 @@ See [this example shader](./examples/resize-custom-shader.frag) for a full docum
 
 If a custom shader fails to compile, niri will print a warning and fall back to the default, or previous successfully compiled shader.
 
-> [!NOTE]
+> [!WARNING]
 > 
 > Custom shaders do not have a backwards compatibility guarantee.
 > I may need to change their interface as I'm developing new features.
 
+Example: resize will show the next (after resize) window texture right away, stretched to the current geometry.
+
 ```
 animations {
     window-resize {
         spring damping-ratio=1.0 stiffness=800 epsilon=0.0001
 
         custom-shader r"
-            #version 100
-            precision mediump float;
-
-            varying vec2 v_coords;
-            uniform mat3 input_to_curr_geo;
-            uniform sampler2D tex_next;
-            uniform mat3 geo_to_tex_next;
-            uniform float alpha;
-
-            void main() {
-                vec3 coords_curr_geo = input_to_curr_geo * vec3(v_coords, 1.0);
-                vec3 coords_tex_next = geo_to_tex_next * coords_curr_geo;
-                vec4 color = texture2D(tex_next, vec2(coords_tex_next));
-                gl_FragColor = color * alpha;
+            vec4 resize_color(vec3 coords_curr_geo, vec3 size_curr_geo) {
+                vec3 coords_tex_next = niri_geo_to_tex_next * coords_curr_geo;
+                vec4 color = texture2D(niri_tex_next, coords_tex_next.st);
+                return color;
             }
         "
     }