apps,litenes,ppu: refactor scanline drawing
This commit is contained in:
Zihao Yu
parent
9d103b1de3
commit
4c772f1a1e
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@ -13,7 +13,6 @@ static byte PPU_RAM[0x4000];
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static bool ppu_2007_first_read;
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static byte ppu_addr_latch;
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static bool ppu_sprite_hit_occured = false;
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static uint16_t ppu_bg_XHLidx[264][(264 + W) / 8];
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static uint16_t pattern2XHLidx[16][256];
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static const word ppu_base_nametable_addresses[4] = { 0x2000, 0x2400, 0x2800, 0x2C00 };
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@ -277,88 +276,89 @@ static void ppu_preprocess(void) {
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extern bool do_update;
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static uint16_t ppu_sprite0_bg_scanline[W / 8];
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void ppu_draw_background_scanline(bool mirror) {
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int tile_y = ppu.scanline >> 3;
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int taddr = base_nametable_address | (tile_y << 5);
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static inline void ppu_check_sprite0_bg_scanline(
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int taddr, int tile_x, int tile_x_max, uint16_t *p_XHLidx) {
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int tile_x_max = 32;
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int tile_x = ppu_shows_background_in_leftmost_8px() ? 0 : 1;
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int skip_tiles = ppu.PPUSCROLL_X >> 3;
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if (mirror) {
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taddr += 0x400;
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// Skipping off-screen pixels
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tile_x_max = skip_tiles + 1;
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}
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else if (ppu.PPUSCROLL_X > 0) {
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tile_x += skip_tiles;
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}
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uint16_t *p_bg = &ppu_bg_XHLidx[ppu.scanline][mirror ? W / 8 : 0];
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uint16_t *p_XHLidx = &pattern2XHLidx[(background_pattern_table_address >> 9) | (ppu.scanline & 7)][0];
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bool is_in_sprite0_scanline = (ppu.scanline >= spr_array[0].y && ppu.scanline < spr_array[0].y + 8);
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if (!ppu_sprite_hit_occured && is_in_sprite0_scanline) {
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for (; tile_x < tile_x_max; tile_x ++) {
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int tile_index = ppu_ram_read_fast(taddr + tile_x);
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uint32_t XHLidx = p_XHLidx[tile_index];
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p_bg[tile_x] = XHLidx;
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if (XHLidx != 0) {
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ppu_sprite0_bg_scanline[tile_x] = XHLidx;
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}
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}
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}
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else {
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for (; tile_x < tile_x_max; tile_x ++) {
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int tile_index = ppu_ram_read_fast(taddr + tile_x);
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uint32_t XHLidx = p_XHLidx[tile_index];
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p_bg[tile_x] = XHLidx;
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}
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for (; tile_x < tile_x_max; tile_x ++) {
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int tile_index = ppu_ram_read_fast(taddr + tile_x);
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uint32_t XHLidx = p_XHLidx[tile_index];
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if (XHLidx != 0) {
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ppu_sprite0_bg_scanline[tile_x] = XHLidx;
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}
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}
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}
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void ppu_update_background_scanline(bool mirror) {
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int scroll_base = 256 - ppu.PPUSCROLL_X;
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int tile_x_max = 32;
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int tile_x = ppu_shows_background_in_leftmost_8px() ? 0 : 1;
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int skip_tiles = ppu.PPUSCROLL_X >> 3;
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if (mirror) {
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scroll_base += 256;
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// Skipping off-screen pixels
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tile_x_max = skip_tiles + 1;
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}
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else if (ppu.PPUSCROLL_X > 0) {
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tile_x += skip_tiles;
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scroll_base += ppu.PPUSCROLL_X & ~0x7;
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}
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void ppu_draw_bg_scanline(
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int taddr, int scroll_base, int tile_x, int tile_x_max,
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uint16_t *p_XHLidx, uint32_t *p_palette_attribute) {
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uint32_t *p_palette_attribute = &palette_attr_cache[(ppu.PPUCTRL & 0x3) + mirror]
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[ppu.scanline >> 4][0];
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uint16_t *p_bg = &ppu_bg_XHLidx[ppu.scanline][mirror ? W / 8 : 0];
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for (; tile_x < tile_x_max; tile_x ++) {
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int tile_index = ppu_ram_read_fast(taddr + tile_x);
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uint32_t XHLidx = p_XHLidx[tile_index];
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for (; tile_x < tile_x_max; tile_x ++) {
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uint32_t XHLidx = p_bg[tile_x];
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// most of the tiles of bg are transparent, which are unnecessary to process
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if (XHLidx != 0) {
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uint32_t *color_cache_line = color_cache[p_palette_attribute[tile_x >> 2]];
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byte *pXHL = &XHL[XHLidx][0];
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if (XHLidx != 0) {
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uint32_t *color_cache_line = color_cache[p_palette_attribute[tile_x >> 2]];
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byte *pXHL = &XHL[XHLidx][0];
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#define macro(x) \
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draw_color(scroll_base + x, ppu.scanline, color_cache_line[pXHL[x]]);
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draw_color(scroll_base + x, ppu.scanline, color_cache_line[pXHL[x]]);
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// loop unrolling
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macro(0); macro(1); macro(2); macro(3);
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macro(4); macro(5); macro(6); macro(7);
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// loop unrolling
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macro(0); macro(1); macro(2); macro(3);
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macro(4); macro(5); macro(6); macro(7);
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#undef macro
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}
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scroll_base += 8;
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}
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scroll_base += 8;
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}
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}
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static inline void check_sprite0_hit(int XHLidx, int y, int hflip) {
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void ppu_bg_scanline_wrapper(void) {
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bool is_in_sprite0_scanline = (ppu.scanline >= spr_array[0].y && ppu.scanline < spr_array[0].y + 8);
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bool check_sprite0 = (!ppu_sprite_hit_occured && is_in_sprite0_scanline);
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int tile_y = ppu.scanline >> 3;
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int taddr_nonmirror = base_nametable_address | (tile_y << 5);
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int taddr_mirror = taddr_nonmirror + 0x400;
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int skip_tiles = ppu.PPUSCROLL_X >> 3;
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int tile_x_max_nonmirror = 32;
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int tile_x_max_mirror = skip_tiles + 1;
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int tile_x_mirror = ppu_shows_background_in_leftmost_8px() ? 0 : 1;
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int tile_x_nonmirror = tile_x_mirror + (ppu.PPUSCROLL_X > 0 ? skip_tiles : 0);
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uint16_t *p_XHLidx = &pattern2XHLidx[(background_pattern_table_address >> 9) | (ppu.scanline & 7)][0];
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if (check_sprite0) {
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// non-mirror pass
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ppu_check_sprite0_bg_scanline(taddr_nonmirror, tile_x_nonmirror, tile_x_max_nonmirror, p_XHLidx);
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// mirror pass
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ppu_check_sprite0_bg_scanline(taddr_mirror, tile_x_mirror, tile_x_max_mirror, p_XHLidx);
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}
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if (do_update) {
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int scroll_base = 256 - ppu.PPUSCROLL_X;
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int scroll_base_mirror = scroll_base + 256;
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int scroll_base_nonmirror = scroll_base + (ppu.PPUSCROLL_X > 0 ? (ppu.PPUSCROLL_X & ~0x7) : 0);
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uint32_t *p_palette_attr_mirror = &palette_attr_cache[(ppu.PPUCTRL & 0x3) + 1][ppu.scanline >> 4][0];
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uint32_t *p_palette_attr_nonmirror = &palette_attr_cache[(ppu.PPUCTRL & 0x3)][ppu.scanline >> 4][0];
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// non-mirror pass
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ppu_draw_bg_scanline(
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taddr_nonmirror, scroll_base_nonmirror, tile_x_nonmirror, tile_x_max_nonmirror,
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p_XHLidx, p_palette_attr_nonmirror);
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// mirror pass
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ppu_draw_bg_scanline(
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taddr_mirror, scroll_base_mirror, tile_x_mirror, tile_x_max_mirror,
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p_XHLidx, p_palette_attr_mirror);
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}
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}
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void check_sprite0_hit(int XHLidx, int y, int hflip) {
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int x;
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if (!ppu_sprite_hit_occured && ppu_shows_background()) {
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for (x = 0; x < 8; x ++) {
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@ -463,12 +463,7 @@ void ppu_cycle() {
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ppu.scanline++;
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if (ppu.scanline < H && ppu_shows_background()) {
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ppu_draw_background_scanline(false);
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ppu_draw_background_scanline(true);
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if (do_update) {
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ppu_update_background_scanline(false);
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ppu_update_background_scanline(true);
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}
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ppu_bg_scanline_wrapper();
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}
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time_read(t2);
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