Sprite overflow games: Difference between revisions
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The sprite overflow flag is rarely used, mainly due to bugs when exactly 8 sprites are present on a scanline. No games rely on this buggy behavior. See [[PPU_sprite_evaluation#Sprite_overflow_bug|sprite overflow bug]] for more details. | The sprite overflow flag is rarely used, mainly due to bugs when exactly 8 sprites are present on a scanline. No games rely on this buggy behavior. See [[PPU_sprite_evaluation#Sprite_overflow_bug|sprite overflow bug]] for more details. | ||
Nonetheless, games can intentionally place 9 or more sprites in a scanline to trigger the overflow flag consistently. | Nonetheless, games can intentionally place 9 or more sprites in a scanline to trigger the overflow flag consistently, as long as no previous scanlines have exactly 8 sprites. | ||
=== Commercial === | === Commercial === | ||
Revision as of 07:27, 27 December 2014
The following is a list of games which rely on putting more than 8 sprites on a scanline.
Use of sprite overflow flag
The sprite overflow flag is rarely used, mainly due to bugs when exactly 8 sprites are present on a scanline. No games rely on this buggy behavior. See sprite overflow bug for more details.
Nonetheless, games can intentionally place 9 or more sprites in a scanline to trigger the overflow flag consistently, as long as no previous scanlines have exactly 8 sprites.
Commercial
- Bee 52: At the title screen, the game splits the screen with sprite overflow (at scanline 165), then splits the screen with a sprite 0 hit (at scanline 207). If sprite overflow is not emulated, the game will crash at a solid blue-purple screen.
Homebrew
- blargg's sprite overflow test ROMs: tests behavior of sprite overflow, including the buggy behavior.
Use of excess sprites for masking effects
Some games intentionally place multiple blank sprites early in the OAM at the same Y position so that other sprites on those scanlines are hidden.
Commercial
- Castlevania II: Simon's Quest (a.k.a. Dracula 2): when Simon enters a swamp, the lower half of his body should be "hidden".
- Felix the Cat: when entering or exiting a bag.
- Gimmick!: when entering a level.
- Gremlins 2 - The New Batch: uses multiple blank sprites to mask rows during cutscenes.
- Majou Densetsu II: Daimashikyou Galious: when entering a doorway, Popolon's body should gradually disappear (to imitate walking down stairs); Youtube video demonstrating the effect.
- Ninja Gaiden: some cutscenes (more details needed).
- The Legend of Zelda (a.k.a. Zelda 1, Zeruda no Densetsu): when entering vertical (top-bottom-facing) doorways.
Misc
Commercial
- Solstice: during the intro cutscene, there are stray sprites on the screen beyond the 8 per scanline, but the NES won't display the excess sprites. This is not a masking effect, it is merely the hardware covering up a mistake that wasn't caught by the original programmers.
References
- BBS topic (with screenshots of Castlevania II: Simon's Quest)
