--- a/shader/sprite_vtx.glsl	Thu Mar 21 20:48:18 2024 +0100
+++ b/shader/sprite_vtx.glsl	Thu Mar 21 22:23:00 2024 +0100
@@ -5,8 +5,12 @@
 
 uniform mat4 projection;
 uniform mat4 model;
+uniform float depth;
 
 void main(void) {
-    gl_Position = projection*model*vec4(position, 0.0, 1.0);
+    vec4 pos = projection*model*vec4(position.x, position.y, 0, 1.0);
+    // apply depth
+    pos.z = depth / -256.0;
+    gl_Position = pos;
     texcoord = vec2(model[0].x, model[1].y)*position;
 }