Keys.

include/level.h

@@ -13,6 +13,7 @@
 typedef struct Level{
 	tile_t content[LEVEL_WIDTH * LEVEL_HEIGHT];
 	Vec2 start_pos;
+	u8 keys;
 } Level;
 
 #include "player.h"
@@ -20,3 +21,4 @@ typedef struct Level{
 void level_load(Level *level, Player *player, u8 id);
 void level_draw(Level level);
 tile_t level_get_tile_at_px(Level level, Vec2 pos);
+void level_set_tile_at_px(Level *level, Vec2 pos, tile_t tile);

include/player.h

@@ -46,6 +46,9 @@ void player_draw(Player player);
 /* Helper functions. */
 bool player_collide(Level level, Vec2 pos, tile_t tile, u8 margin);
 bool player_move(Player *player, Level level, i8 spd_x, i8 spd_y);
+u8 player_collide_key(Level *level, vec2_int_t x, vec2_int_t y);
+void player_collide_keys(Player *player, Level *level);
+
 i8 sign(i8 value);
 f32 signf(f32 value);
 i8 round(f32 value);

kble.py

@@ -95,15 +95,20 @@ if __name__ == "__main__":
                 data = kble_parse(BYTES)
                 start_x = 0
                 start_y = 0
+                keys = 0
                 for y, line in enumerate(data):
                     for x, tile in enumerate(line):
                         c_file.write(str(tile))
                         c_file.write(", ")
                         if tile == 3: # spawn tile
                             start_x, start_y = x, y
+                        if tile == 5: # key tile
+                            keys += 1
             c_file.write("},\n")
             c_file.write("\t\t.start_pos = (Vec2){")
             c_file.write(f"{start_x} * TILE_SIZE + 2, {start_y} * TILE_SIZE + 4")
-            c_file.write("}\n\t},\n")
+            c_file.write("},\n")
+            c_file.write(f"\t\t.keys = {keys}\n")
+            c_file.write("\t},\n")
         c_file.write("};")
 

src/level.c

@@ -38,8 +38,10 @@ void level_load(Level *level, Player *player, u8 id) {
 	extern Level levels[LEVEL_SIZE];
 	memcpy(level->content, levels[id].content, LEVEL_SIZE);
 	level->start_pos = levels[id].start_pos;
+	level->keys = levels[id].keys;
 	player_init(player);
 	player->pos = levels[id].start_pos;
+	player->keys_left = levels[id].keys;
 }
 
 tile_t level_get_tile_at_px(Level level, Vec2 pos) {

src/player.c

@@ -98,7 +98,7 @@ void player_update(Player *player, Level *level, Input input, u8 *level_id) {
 	if (player_collide(*level, player->pos, PAIN_TILE, 5)) {
 		if (!player->knocked) {
 			player->spd_y = -signf(player->spd_y) * KNOCKBACK_Y;
-			player->spd_x = -signf(player->facing) * KNOCKBACK_X;
+			player->spd_x = KNOCKBACK_X * -player->facing;
 			player->knocked = true;
 		}
 		player->stun = true;
@@ -117,6 +117,8 @@ void player_update(Player *player, Level *level, Input input, u8 *level_id) {
 		player_init(player);
 		player->pos = level->start_pos;
 	}
+	/* Get keys. */
+	player_collide_keys(player, level);
 	/* Exit, victory! */
 	if (player->keys_left == 0 && player_collide(*level, player->pos, EXIT_TILE, 0)) {
 		*level_id += 1;
@@ -139,14 +141,14 @@ void player_draw(Player player) {
 /* Helper functions */
 
 bool player_collide(Level level, Vec2 pos, tile_t tile, u8 margin) {
-	const vec2_int_t left = pos.x + margin;
-	const vec2_int_t right = pos.x + PLAYER_WIDTH - 1 - margin;
-	const vec2_int_t up = pos.y + margin;
-	const vec2_int_t down = pos.y + PLAYER_HEIGHT - 1 - margin;
-	return ((tile == level_get_tile_at_px(level, (Vec2){left, up})) ||
-		(tile == level_get_tile_at_px(level, (Vec2){right, up})) ||
-		(tile == level_get_tile_at_px(level, (Vec2){left, down})) ||
-		(tile == level_get_tile_at_px(level, (Vec2){right, down})));
+	const vec2_int_t xl = pos.x + margin;
+	const vec2_int_t xr = pos.x + PLAYER_WIDTH - 1 - margin;
+	const vec2_int_t yt = pos.y + margin;
+	const vec2_int_t yb = pos.y + PLAYER_HEIGHT - 1 - margin;
+	return ((tile == level_get_tile_at_px(level, (Vec2){xl, yt})) ||
+		(tile == level_get_tile_at_px(level, (Vec2){xr, yt})) ||
+		(tile == level_get_tile_at_px(level, (Vec2){xl, yb})) ||
+		(tile == level_get_tile_at_px(level, (Vec2){xr, yb})));
 }
 
 bool player_move(Player *player, Level level, i8 spd_x, i8 spd_y) {
@@ -167,6 +169,30 @@ bool player_move(Player *player, Level level, i8 spd_x, i8 spd_y) {
 	return false;
 }
 
+/* Seek for a key tile at given position, if found destroy it and return 1.
+ * Otherwise, return 0. */
+u8 player_collide_key(Level *level, vec2_int_t x, vec2_int_t y) {
+	if (level_get_tile_at_px(*level, (Vec2){x, y}) == KEY_TILE) {
+		level_set_tile_at_px(level, (Vec2){x, y}, AIR_TILE);
+		return 1;
+	}
+	return 0;
+}
+
+/* Destroy keys the player is touching and deduce them from keys left. */
+void player_collide_keys(Player *player, Level *level) {
+	const vec2_int_t xl = player->pos.x;
+	const vec2_int_t xr = xl + PLAYER_WIDTH - 1;
+	const vec2_int_t yt = player->pos.y;
+	const vec2_int_t yb = yt + PLAYER_HEIGHT - 1;
+	player->keys_left -=
+		player_collide_key(level, xl, yt) +
+		player_collide_key(level, xr, yt) +
+		player_collide_key(level, xl, yb) +
+		player_collide_key(level, xr, yb);
+}
+
+/* Used by `collide_keys()`. Don't call this one directly. */
 i8 sign(i8 value) {
 	if (value > 0)
 		return 1;