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Fix enemy rendering screen offset and implement pixel-perfect sprite collision

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Matteo Benedetto
2026-06-22 19:50:44 +02:00
parent 9311e5d1d3
commit b47455c5d2
2 changed files with 18 additions and 10 deletions
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engine.c
+16 -8
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@@ -8,7 +8,7 @@
#include "tiles.h"
#include "player.h"
#define MAP_SIZE 15
#define MAP_SIZE 7
uint8_t maze[MAP_SIZE][MAP_SIZE];
static uint8_t map_buffer[32 * 32];
@@ -386,7 +386,7 @@ void engine_update(uint8_t keys, uint8_t prev_keys) {
}
}
// Render enemy sprite relative to the scroll viewport
// Render enemy sprite relative to the scroll viewport with centering offset
int16_t enemy_px, enemy_py;
if (enemy_is_moving) {
enemy_px = enemy_start_px + (((enemy_target_px - enemy_start_px) * (int16_t)enemy_move_progress) >> 4);
@@ -396,8 +396,9 @@ void engine_update(uint8_t keys, uint8_t prev_keys) {
enemy_py = (enemy_lx + enemy_ly) * 8 + 16;
}
int16_t enemy_screen_x = enemy_px - scroll_x;
int16_t enemy_screen_y = enemy_py - scroll_y;
// Add player centering offset (+24, +16) to align with player sprite at (88, 88)
int16_t enemy_screen_x = enemy_px - scroll_x + 24;
int16_t enemy_screen_y = enemy_py - scroll_y + 16;
// Determine player-enemy distance for visibility masking
int8_t edx = (int8_t)player_lx - (int8_t)enemy_lx;
@@ -413,10 +414,17 @@ void engine_update(uint8_t keys, uint8_t prev_keys) {
move_metasprite(enemy_metasprite, 0, 4, 0, 0); // Hide offscreen
}
// Collision detection / Game Over conditions
if ((player_lx == enemy_lx && player_ly == enemy_ly) ||
(is_moving && enemy_is_moving && target_lx == enemy_target_lx && target_ly == enemy_target_ly) ||
(is_moving && enemy_is_moving && target_lx == enemy_start_lx && target_ly == enemy_start_ly && start_lx == enemy_target_lx && start_ly == enemy_target_ly)) {
// Get current interpolated player coordinates
int16_t p_px = is_moving ? (start_px + (((target_px - start_px) * (int16_t)move_progress) >> 4)) : ((player_lx - player_ly) * 16 + 96);
int16_t p_py = is_moving ? (start_py + (((target_py - start_py) * (int16_t)move_progress) >> 4)) : ((player_lx + player_ly) * 8 + 16);
// Collision detection: check actual pixel distance (sprites overlap)
int16_t dx_collision = p_px - enemy_px;
int16_t dy_collision = p_py - enemy_py;
if (dx_collision < 0) dx_collision = -dx_collision;
if (dy_collision < 0) dy_collision = -dy_collision;
if (dx_collision < 12 && dy_collision < 6) {
game_over = 1;
BGP_REG = 0xFF; // Screen all black
return;