Return size 0 for NULL array, correct for min/max in spatial grid

engine/breeze/util/array.c

@@ -28,6 +28,7 @@ void _bzArrayClear(void *arr) {
 }
 
 i32 _bzArraySize(void *arr) {
+    if (arr == NULL) return 0;
     return ARRAY_HEAD(arr)->size;
 }
 i32 _bzArrayCapacity(void *arr) {

engine/breeze/util/spatial_grid.c

@@ -104,6 +104,17 @@ static BzSpatialGridIndex calculateGridIndex(BzSpatialGrid *grid, f32 posX, f32
     if (index.minY < 0) index.minY = 0;
     if (index.maxX >= grid->width) index.maxX = grid->width - 1;
     if (index.maxY >= grid->height) index.maxY = grid->height - 1;
+
+    if (index.minX > index.maxX) {
+        i32 tmp = index.minX;
+        index.minX = index.maxX;
+        index.maxX = tmp;
+    }
+    if (index.minY > index.maxY) {
+        i32 tmp = index.minY;
+        index.minY = index.maxY;
+        index.maxX = tmp;
+    }
     return index;
 }