fixed minor regression, cleaned up source tree

src/vkprocessor/shader_kernels.rs

@@ -244,7 +244,7 @@ impl ShaderKernels {
                     third_constant: 0.0,
                 })
                 // The content of the vertex buffer describes a list of triangles.
-                .triangle_list_with_adjacency()
+                .triangle_fan()
                 // Use a resizable viewport set to draw over the entire window
                 .viewports_dynamic_scissors_irrelevant(1)
                 // See `vertex_shader`.