Resolve "Voxel cone tracing"

Closes #82 (closed)

projects/voxelization/resources/shaders/luma.inc

+#ifndef LUMA_INC
+#define LUMA_INC
+
+float computeLuma(vec3 c){
+    return dot(c, vec3(0.21, 0.72, 0.07));
+}
+
+#endif // #ifndef LUMA_INC
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