feat: post-processing effects

res/shaders/effect.glslf

@@ -0,0 +1,13 @@
+in vec2 v_uv;
+out vec4 f_color;
+
+uniform sampler2D u_screen;
+uniform ivec2 u_screenSize;
+uniform float u_intensity;
+
+#include <__effect__>
+
+void main() {
+    f_color = effect();
+}
+