Resolve "Voxel cone tracing"

Closes #82 (closed)

projects/voxelization/resources/shaders/depthPrepass.frag

@@ -2,6 +2,13 @@
 #extension GL_ARB_separate_shader_objects : enable
 #extension GL_GOOGLE_include_directive : enable
 
-void main()	{
+#include "perMeshResources.inc"
+
+layout(location = 0) in vec2 passUV;
 
+void main()	{
+    float alpha = texture(sampler2D(albedoTexture, textureSampler), passUV).a;
+    if(alpha < 0.5){
+        discard;
+    }
 }
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