Use GL_ARB_conservative_depth when possible

- Allows the depth test to discard fragments before the fragment shader is run

src/main/resources/assets/create/flywheel/shaders/context/contraption.glsl

@@ -39,12 +39,13 @@ void FLWFinalizeWorldPos(inout vec4 worldPos) {
 #use "flywheel:core/lightutil.glsl"
 
 #define ALPHA_DISCARD 0.1
-//
-//#if defined(ALPHA_DISCARD)
-//#if defined(GL_ARB_conservative_depth)
-//layout (depth_greater) out float gl_FragDepth;
-//#endif
-//#endif
+// optimize discard usage
+#if defined(ALPHA_DISCARD)
+#if defined(GL_ARB_conservative_depth)
+#extension GL_ARB_conservative_depth : enable
+layout (depth_greater) out float gl_FragDepth;
+#endif
+#endif
 
 in vec3 BoxCoord;