More progress.

src/shared/grid.c

@@ -6,6 +6,19 @@
 #define GRID_MIN_WIDTH 8
 #define GRID_MIN_HEIGHT 8
 
+static bool from_grid_index(Grid *grid, uint16_t grid_index, uint16_t *out_x, uint16_t *out_y) {
+    assert(grid != NULL);
+    assert(out_x != NULL);
+    assert(out_y != NULL);
+
+    if (!grid || !out_x || !out_y) return false;
+    if (grid_index >= grid->width * grid->height) return false;
+
+    *out_x = grid_index % grid->width;
+    *out_y = grid_index / grid->width;
+    return true;
+}
+
 bool grid_initialize(Grid *grid, uint16_t width, uint16_t height) {
     assert(grid != NULL);
 
@@ -16,6 +29,12 @@ bool grid_initialize(Grid *grid, uint16_t width, uint16_t height) {
     grid->width = width;
     grid->height = height;
     grid->cells = calloc(width * height, sizeof(Grid_Cell));
+
+    for(uint16_t i = 0; i < (width * height); i++) {
+        Grid_Cell *cell = &grid->cells[i];
+        assert(from_grid_index(grid, i, &cell->x, &cell->y));
+    }
+    
     return true;
 }
 
@@ -37,19 +56,6 @@ static bool to_grid_index(Grid *grid, uint16_t x, uint16_t y, uint16_t *out_grid
     return true;
 }
 
-static bool from_grid_index(Grid *grid, uint16_t grid_index, uint16_t *out_x, uint16_t *out_y) {
-    assert(grid != NULL);
-    assert(out_x != NULL);
-    assert(out_y != NULL);
-
-    if (!grid || !out_x || !out_y) return false;
-    if (grid_index >= grid->width * grid->height) return false;
-
-    *out_x = grid_index % grid->width;
-    *out_y = grid_index / grid->width;
-    return true;
-}
-
 Grid_Cell *grid_get_cell(Grid *grid, uint16_t x, uint16_t y) {
     assert(grid != NULL);
     if(x >= grid->width || y >= grid->height) return NULL;
@@ -60,4 +66,36 @@ Grid_Cell *grid_get_cell(Grid *grid, uint16_t x, uint16_t y) {
     }
     
     return &grid->cells[grid_index];
+}
+
+bool grid_try_add_entity_to_cell(Grid_Cell *cell, Entity *entity) {
+    assert(cell != NULL);
+    assert(entity != NULL);
+
+    // TODO: SS - Could check what type of cell it is to determine if
+    // we're allowed to place an entity here. Is it a wall? Lava?
+    
+    if(cell->entity != NULL) {
+        return false;
+    }
+
+    cell->entity = entity;
+    entity->x = cell->x;
+    entity->y = cell->y;
+    
+    return true;
+}
+
+bool grid_try_remove_entity_from_cell(Grid_Cell *cell) {
+    assert(cell != NULL);
+
+    if(cell->entity == NULL) {
+        return false;
+    }
+
+    cell->entity->x = 0;
+    cell->entity->y = 0;
+    cell->entity = NULL;
+
+    return true;
 }