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apps,litenes,ppu: fix buffer overflow bug when drawing sprite with y > H

This commit is contained in:
Zihao Yu 2019-05-02 18:18:35 +08:00
parent b7af5518f6
commit aa54af854c
1 changed files with 3 additions and 2 deletions
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5
apps/litenes/src/ppu.c
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@ -386,12 +386,13 @@ void ppu_draw_sprite_scanline() {
for (i = 0; i < nr_sprite; i ++) {
n = sprite_per_scanline_list[ppu.scanline][i];
int y_in_tile = ppu.scanline & 0x7;
uint32_t y = spr_array[n].y + y_in_tile;
if (y >= H) continue;
bool vflip = spr_array[n].atr & 0x80;
bool hflip = spr_array[n].atr & 0x40;
int y_in_tile = ppu.scanline & 0x7;
uint32_t y = spr_array[n].y + y_in_tile;
uint32_t tile_address = sprite_pattern_table_address + 16 * spr_array[n].tile + (vflip ? (7 - y_in_tile) : y_in_tile);
uint32_t l = ppu_ram_read_fast(tile_address);
uint32_t XHLidx = (ppu_ram_read_fast(tile_address + 8) << 8) | l;