ClipBounds.shader

void ClipBounds(float4 bounds, float2 pos) {
		float2 min = bounds.xy;
		float2 max = bounds.zw;

		float a = step(min.x, pos.x);
		float b = step(pos.x, max.x);

		float c = step(min.y, pos.y);
		float d = step(pos.y, max.y);
		clip(3.0f - a - b - c - d);
	}
	
	// Call from surface shader like so
	ClipBounds(_Mask1, IN.worldPos.xz);