New helper function converting grid space to flat index.

src/map.odin

@@ -122,12 +122,16 @@ world_to_grid :: proc(world_pos: rl.Vector2) -> Grid_Pos {
 }
 
 // returns world-space position grid pos top-left corner opposite of world_to_grid.
-grid_to_world :: proc(col: int, row: int) -> rl.Vector2 {
+grid_to_world :: proc(col, row: int) -> rl.Vector2 {
 	world_x := f32(col * TILE_SIZE)
 	world_y := f32(row * TILE_SIZE)
 	return rl.Vector2{world_x, world_y}
 }
 
+grid_to_index :: proc(col, row, width: int) -> int {
+	return (row * width) + col
+}
+
 // requires world x/y and then gives the rectangle in pixels that matches that
 get_world_tile_rect :: proc(gx, gy, offset_x, offset_y, w, h: f32) -> rl.Rectangle {
 	return rl.Rectangle {