Calculate the focus factor z in the post shader

res/shaders/post.frag

@@ -11,9 +11,11 @@ uniform uint windowHeight;
 uniform float time;
 
 void main() {
-    float dx = 1.0/windowWidth;
-    float dy = 1.0/windowHeight;
-    
+    vec2 dx = vec2(1,0) * 1.0/windowWidth;
+    vec2 dy = vec2(0,1) * 1.0/windowHeight;
     vec2 UV = gl_FragCoord.xy / vec2(windowWidth, windowHeight);
-    color_out = texture(framebuffer, UV);
+
+    float z = pow(texture(depthbuffer, UV).r , 0x800);
+    z = abs(z*2-1)*1.2;
+    color_out = vec4(vec3(texture(depthbuffer, UV).r), 1.0);
 }

res/shaders/post.vert

@@ -1,9 +1,7 @@
 #version 430 core
 
 in layout(location = 0) vec3 vertex;
-out layout(location = 0) vec2 UV;
 
 void main() {
     gl_Position = vec4(vertex, 1.0);
-    UV = vertex.xy*0.5 + 0.5;
 }

src/renderlogic.cpp

@@ -341,9 +341,9 @@ void renderFrame(GLFWwindow* window, int windowWidth, int windowHeight) {
     glDepthMask(GL_FALSE); // read only
     for (NodeDistShader a : transparent_nodes)
         renderNode(a.node, a.s, nullptr, false);
+    renderNode(hudNode, nullptr); // rootNode defined in scene.hpp
     glDepthMask(GL_TRUE); // read write
 
-    renderNode(hudNode, nullptr); // rootNode defined in scene.hpp
   
     // render framebuffer to window
     glBindFramebuffer(GL_FRAMEBUFFER, 0);