feat: process external custom block models for variable textures

src/maths/UVRegion.hpp

@@ -2,6 +2,7 @@
 
 #include <cmath>
 #include <glm/vec2.hpp>
+#include <glm/vec4.hpp>
 
 struct UVRegion {
     float u1;
@@ -51,4 +52,11 @@ struct UVRegion {
         u2 = cx + w * 0.5f * x;
         v2 = cy + h * 0.5f * y;
     }
+
+    void set(const glm::vec4& vec) {
+        u1 = vec.x;
+        v1 = vec.y;
+        u2 = vec.z;
+        v2 = vec.w;
+    }
 };