feat: post-processing effects

res/shaders/effect.glslv

@@ -0,0 +1,10 @@
+layout (location = 0) in vec2 v_position;
+
+out vec2 v_uv;
+
+uniform ivec2 u_screenSize;
+
+void main(){
+    v_uv = v_position * 0.5 + 0.5;
+    gl_Position = vec4(v_position, 0.0, 1.0);
+}