OpenXiangShan
/
nexus-am
mirror of https://github.com/OpenXiangShan/nexus-am.git
3
0
Fork 0
Code Issues Projects Releases Wiki Activity

apps,litenes,ppu: optimize ppu_draw_sprite_scanline()

This commit is contained in:
Zihao Yu 2019-04-24 22:15:25 +08:00
parent b4e5514aee
commit b6556c8cd6
1 changed files with 22 additions and 21 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

43
apps/litenes/src/ppu.c
View File

@ -279,13 +279,22 @@ void ppu_draw_background_scanline(bool mirror) {
}
void ppu_draw_sprite_scanline() {
log("====\n");
int do_update = frame_cnt % 3 == 0;
int scanline_sprite_count = 0;
int n;
int i, n;
int sprite_palette_cache[4][4];
for (i = 0; i < 4; i ++) {
uint32_t palette_address = 0x3F10 + (i << 2);
// still in the range of identify mapping, can bypass ppu_ram_map[]
sprite_palette_cache[i][1] = ppu_ram_read_fast(palette_address + 1);
sprite_palette_cache[i][2] = ppu_ram_read_fast(palette_address + 2);
sprite_palette_cache[i][3] = ppu_ram_read_fast(palette_address + 3);
}
for (n = 0; n < 0x100; n += 4) {
byte sprite_x = PPU_SPRRAM[n + 3];
byte sprite_y = PPU_SPRRAM[n];
uint32_t sprite_x = PPU_SPRRAM[n + 3];
uint32_t sprite_y = PPU_SPRRAM[n];
// Skip if sprite not on scanline
if (sprite_y > ppu.scanline || sprite_y + sprite_height < ppu.scanline)
@ -296,42 +305,34 @@ void ppu_draw_sprite_scanline() {
// PPU can't render > 8 sprites
if (scanline_sprite_count > 8) {
ppu_set_sprite_overflow(true);
return;
// break;
}
bool vflip = PPU_SPRRAM[n + 2] & 0x80;
bool hflip = PPU_SPRRAM[n + 2] & 0x40;
word tile_address = sprite_pattern_table_address + 16 * PPU_SPRRAM[n + 1];
uint32_t tile_address = sprite_pattern_table_address + 16 * PPU_SPRRAM[n + 1];
int y_in_tile = ppu.scanline & 0x7;
log("call ppu_ram_read\n");
byte l = ppu_ram_read(tile_address + (vflip ? (7 - y_in_tile) : y_in_tile));
log("call ppu_ram_read\n");
byte h = ppu_ram_read(tile_address + (vflip ? (7 - y_in_tile) : y_in_tile) + 8);
uint32_t l = ppu_ram_read_fast(tile_address + (vflip ? (7 - y_in_tile) : y_in_tile));
uint32_t h = ppu_ram_read_fast(tile_address + (vflip ? (7 - y_in_tile) : y_in_tile) + 8);
byte palette_attribute = PPU_SPRRAM[n + 2] & 0x3;
word palette_address = 0x3F10 + (palette_attribute << 2);
uint32_t palette_attribute = PPU_SPRRAM[n + 2] & 0x3;
int *palette_cache_line = sprite_palette_cache[palette_attribute];
int x;
for (x = 0; x < 8; x++) {
int color = hflip ? XHL[h][l][7 - x] : XHL[h][l][x];
int color = XHL[h][l][ (hflip ? 7 - x : x) ];
// Color 0 is transparent
if (color != 0) {
int screen_x = sprite_x + x;
if (do_update) {
log("call ppu_ram_read\n");
int idx = ppu_ram_read(palette_address + color);
if (PPU_SPRRAM[n + 2] & 0x20) {
draw(screen_x, sprite_y + y_in_tile + 1, idx); // bbg
}
else {
draw(screen_x, sprite_y + y_in_tile + 1, idx); // fg
}
draw(screen_x, sprite_y + y_in_tile + 1, palette_cache_line[color]);
}
// Checking sprite 0 hit
if (ppu_shows_background() && !ppu_sprite_hit_occured && n == 0 && ppu_screen_background[sprite_y + y_in_tile][screen_x] == color) {
if (n == 0 && !ppu_sprite_hit_occured && ppu_shows_background() && ppu_screen_background[sprite_y + y_in_tile][screen_x] == color) {
ppu_set_sprite_0_hit(true);
ppu_sprite_hit_occured = true;
}