minor code cleanup

[rocksndiamonds.git] / src / game_bd / bd_graphics.c

diff --git a/src/game_bd/bd_graphics.c b/src/game_bd/bd_graphics.c
index 8938ab80d8c23444dd674846dce14e12d4047b28..fb3ec4dff4d407b5cf3e6da8c62709037354acd2 100644 (file)
--- a/src/game_bd/bd_graphics.c
+++ b/src/game_bd/bd_graphics.c
@@ -292,6 +292,18 @@ static boolean use_native_bd_graphics_engine(void)
 }
 #endif
 
+/* returns true if the element is a player */
+static inline boolean is_player(const int element)
+{
+  return (gd_elements[element & O_MASK].properties & P_PLAYER) != 0;
+}
+
+/* returns true if the element is collectible */
+static inline boolean is_collectible(const int element)
+{
+  return (gd_elements[element & O_MASK].properties & P_COLLECTIBLE) != 0;
+}
+
 int gd_drawcave(Bitmap *dest, GdGame *game, boolean force_redraw)
 {
   GdCave *cave = game->cave;
@@ -357,8 +369,13 @@ int gd_drawcave(Bitmap *dest, GdGame *game, boolean force_redraw)
          if (!(game->last_element_buffer[y][x] & SKIPPED))
          {
            /* redraw previous game element on the cave field the new element is moving to */
-           int tile_old = game->last_element_buffer[y][x];
-           struct GraphicInfo_BD *g_old = &graphic_info_bd_object[tile_old][frame];
+           int tile_last = game->last_element_buffer[y][x];
+
+           /* only redraw previous game element if it is not collectible (like dirt etc.) */
+           if (is_collectible(tile_last))
+             tile_last = O_SPACE;
+
+           struct GraphicInfo_BD *g_old = &graphic_info_bd_object[tile_last][frame];
 
            blit_bitmap(g_old->bitmap, dest, g_old->src_x, g_old->src_y, cell_size, cell_size,
                        sx, sy);
@@ -369,18 +386,20 @@ int gd_drawcave(Bitmap *dest, GdGame *game, boolean force_redraw)
          int dy = (dir == GD_MV_UP   ? +1 : dir == GD_MV_DOWN  ? -1 : 0);
          int old_x = cave->getx(cave, x + dx, y + dy);
          int old_y = cave->gety(cave, x + dx, y + dy);
-
-         if (old_x >= cave->x1 &&
-             old_x <= cave->x2 &&
-             old_y >= cave->y1 &&
-             old_y <= cave->y2)
+         int tile_from = game->element_buffer[old_y][old_x];
+         struct GraphicInfo_BD *g_from = &graphic_info_bd_object[tile_from][frame];
+         boolean old_is_player = is_player(tile_from);
+         boolean old_is_moving = (game->dir_buffer[old_y][old_x] != GD_MV_STILL);
+         boolean old_is_visible = (old_x >= cave->x1 &&
+                                   old_x <= cave->x2 &&
+                                   old_y >= cave->y1 &&
+                                   old_y <= cave->y2);
+
+         if (old_is_visible)
          {
-           if (game->dir_buffer[old_y][old_x] == GD_MV_STILL)
+           if (!old_is_moving && !old_is_player)
            {
              /* redraw game element on the cave field the element is moving from */
-             int tile_from = game->element_buffer[old_y][old_x];
-             struct GraphicInfo_BD *g_from = &graphic_info_bd_object[tile_from][0];
-
              blit_bitmap(g_from->bitmap, dest, g_from->src_x, g_from->src_y, cell_size, cell_size,
                          sx + dx * cell_size, sy + dy * cell_size);
 
@@ -388,7 +407,7 @@ int gd_drawcave(Bitmap *dest, GdGame *game, boolean force_redraw)
            }
            else
            {
-             /* if old tile also moving (like pushing player), do not redraw it again */
+             /* if old tile also moving (like pushing player), do not redraw tile background */
              game->last_element_buffer[old_y][old_x] |= SKIPPED;
            }
          }
@@ -397,11 +416,21 @@ int gd_drawcave(Bitmap *dest, GdGame *game, boolean force_redraw)
          int itercycle = MIN(MAX(0, game->itermax - game->itercycle - 1), game->itermax);
          int shift = cell_size * itercycle / game->itermax;
 
-         sx += dx * shift;
-         sy += dy * shift;
-       }
+         blit_bitmap(g->bitmap, dest, g->src_x, g->src_y, cell_size, cell_size,
+                     sx + dx * shift, sy + dy * shift);
 
-       blit_bitmap(g->bitmap, dest, g->src_x, g->src_y, cell_size, cell_size, sx, sy);
+         /* special case: redraw player snapping a game element */
+         if (old_is_visible && old_is_player && !old_is_moving)
+         {
+           /* redraw game element on the cave field the element is moving from */
+           blit_bitmap(g_from->bitmap, dest, g_from->src_x, g_from->src_y, cell_size, cell_size,
+                       sx + dx * cell_size, sy + dy * cell_size);
+         }
+       }
+       else
+       {
+         blit_bitmap(g->bitmap, dest, g->src_x, g->src_y, cell_size, cell_size, sx, sy);
+       }
 
 #if DO_GFX_SANITY_CHECK
        if (use_native_bd_graphics_engine() && !setup.small_game_graphics && !program.headless)