Dynamic Y draw offset depending on player position.

include/conf.h

@@ -12,5 +12,7 @@
 #define LEVEL_WIDTH 16
 #define LEVEL_HEIGHT 16
 #define LEVEL_SIZE (LEVEL_WIDTH * LEVEL_HEIGHT)
+#define LEVEL_WIDTH_PX (LEVEL_WIDTH * TILE_SIZE)
+#define LEVEL_HEIGHT_PX (LEVEL_HEIGHT * TILE_SIZE)
 #define DRAW_OFFSET_X 70
 #define DRAW_OFFSET_Y -16

include/level.h

@@ -19,6 +19,6 @@ typedef struct Level{
 #include "player.h"
 
 void level_load(Level *level, Player *player, u8 id);
-void level_draw(Level level);
+void level_draw(Level level, i16 y_offset);
 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

@@ -42,7 +42,7 @@ typedef struct Player{
 
 void player_init(Player *player);
 void player_update(Player *player, Level *level, Input input, u8 *level_id);
-void player_draw(Player player);
+void player_draw(Player player, i16 y_offset);
 /* 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);

src/level.c

@@ -13,10 +13,10 @@
 #include "player.h"
 #include "vec2.h"
 
-void level_draw(Level level) {
+void level_draw(Level level, i16 y_offset) {
 	/* Pixel position (where we draw). */
-	u16 x = DRAW_OFFSET_X;
-	u16 y = DRAW_OFFSET_Y;
+	i32 x = DRAW_OFFSET_X;
+	i16 y = y_offset;
 	/* Cursor position. */
 	u8 cx = 0;
 	while (cx < LEVEL_WIDTH) {
@@ -28,7 +28,7 @@ void level_draw(Level level) {
 			y += TILE_SIZE;
 			cy += 1;
 		}
-		y = DRAW_OFFSET_Y;
+		y = y_offset;
 		x += TILE_SIZE;
 		cx += 1;
 	}
@@ -52,7 +52,7 @@ tile_t level_get_tile_at_px(Level level, Vec2 pos) {
 	u8 x = pos.x / TILE_SIZE;
 	u8 y = pos.y / TILE_SIZE;
 	/* Out of bounds check. */
-	if (pos.x >= LEVEL_WIDTH * TILE_SIZE || pos.y >= LEVEL_HEIGHT * TILE_SIZE)
+	if (pos.x >= LEVEL_WIDTH_PX || pos.y >= LEVEL_HEIGHT_PX)
 		return OUT_OF_BOUNDS;
 	/* If everything is OK, get the tile and return it. */
 	return level.content[x + y * LEVEL_WIDTH];

src/main.c

@@ -48,10 +48,13 @@ int main(void) {
 			input_update(&input);
 			player_update(&player, &level, input, &level_id);
 		}
+		/* Calculate y offset ("camera"). */
+		const i16 y_offset = ((f32)player.pos.y / (f32)LEVEL_HEIGHT_PX) *
+		                     (DHEIGHT - LEVEL_HEIGHT_PX);
 		/* Draw. */
 		dclear(C_BLACK);
-		level_draw(level);
-		player_draw(player);
+		level_draw(level, y_offset);
+		player_draw(player, y_offset);
 		dupdate();
 	}
 

src/player.c

@@ -111,8 +111,8 @@ void player_update(Player *player, Level *level, Input input, u8 *level_id) {
 	/* Return to last checkpoint if out of bounds. */
 	if ((player->pos.x <= -PLAYER_WIDTH) ||
 	    (player->pos.y <= -PLAYER_HEIGHT) ||
-	    (player->pos.x >= LEVEL_WIDTH * TILE_SIZE) ||
-	    (player->pos.y >= LEVEL_HEIGHT * TILE_SIZE))
+	    (player->pos.x >= LEVEL_WIDTH_PX) ||
+	    (player->pos.y >= LEVEL_HEIGHT_PX))
 	{
 		player_init(player);
 		player->pos = level->start_pos;
@@ -126,7 +126,7 @@ void player_update(Player *player, Level *level, Input input, u8 *level_id) {
 	}
 }
 
-void player_draw(Player player) {
+void player_draw(Player player, i16 y_offset) {
 	/* Draw colored rectangle depending on player state. */
 	u32 color = 0;
 	if (player.stun)
@@ -134,7 +134,7 @@ void player_draw(Player player) {
 	else
 		color = C_RGB(0/8, 121/8, 241/8); /* Blue. */
 	const vec2_int_t x = player.pos.x + DRAW_OFFSET_X;
-	const vec2_int_t y = player.pos.y + DRAW_OFFSET_Y;
+	const vec2_int_t y = player.pos.y + y_offset;
 	drect(x, y, x + PLAYER_WIDTH - 1, y + PLAYER_HEIGHT - 1, color);
 }