finish changing voxel storage to a 1d aray

shaders/cube_frag.glsl

@@ -13,10 +13,10 @@ void main()
     // You can now use v_VoxelKind to modify the color
     // Example: Different colors for different voxel types
     vec3 color = u_Color;
-    if (v_VoxelKind == 0.0) {
+    if (v_VoxelKind == 1.0) {
         // Dirt - brownish
         color *= vec3(0.6, 0.4, 0.2);
-    } else if (v_VoxelKind == 1.0) {
+    } else if (v_VoxelKind == 2.0) {
         // Stone - grayish (keep as is)
     }