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chore: correct logic errors in map size 1 and 3

This commit is contained in:
Rekai Nyangadzayi Musuka 2022-02-16 23:49:08 -04:00
parent 4018f3875b
commit 07343efdf3
1 changed files with 24 additions and 9 deletions
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33
src/ppu.zig
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@ -87,15 +87,15 @@ pub const Ppu = struct {
const vofs = self.bg[n].vofs.offset.read();
const hofs = self.bg[n].hofs.offset.read();
const y = scanline + vofs;
const y = vofs + scanline;
var i: u32 = 0;
while (i < width) : (i += 1) {
const x = i + hofs;
const x = hofs + i;
// Grab the Screen Entry from VRAM
const entry_addr = screen_base + tilemapOffset(size, x, y);
const entry = @bitCast(ScreenEntry, @as(u16, self.vram.get16(entry_addr)));
const entry = @bitCast(ScreenEntry, self.vram.get16(entry_addr));
// Calculate the Address of the Tile in the designated Charblock
// We also take this opportunity to flip tiles if necessary
@ -112,13 +112,13 @@ pub const Ppu = struct {
// If we're in 8bpp, then the tile value is an index into the palette,
// If we're in 4bpp, we have to account for a pal bank value in the Screen entry
// and then we can index the palette
const colour = if (!is_8bpp) blk: {
const pal_id = if (!is_8bpp) blk: {
tile = if (col & 1 == 1) tile >> 4 else tile & 0xF;
const pal_bank: u8 = @as(u8, entry.palette_bank.read()) << 4;
break :blk pal_bank | tile;
} else tile;
std.mem.copy(u8, scanline_buf[i * 2 ..][0..2], self.palette.buf[colour * 2 ..][0..2]);
std.mem.copy(u8, scanline_buf[i * 2 ..][0..2], self.palette.buf[pal_id * 2 ..][0..2]);
}
std.mem.copy(u8, self.framebuf[start..][0..framebuf_pitch], &scanline_buf);
@ -168,11 +168,26 @@ pub const Ppu = struct {
// Current COlumn: (x % PIXEL_COUNT) / 8
// Length of 1 row of Screen Entries: 0x40
// Length of 1 Screen Entry: 0x2 is the size of a screen entry
@setRuntimeSafety(false);
return switch (size) {
0 => (y % 256 / 8) * 0x40 + (x % 256 / 8) * 2, // 256 x 256
1 => (y % 512 / 8) * 0x40 + (x % 256 / 8) * 2, // 512 x 256
2 => (y % 256 / 8) * 0x40 + (x % 512 / 8) * 2, // 256 x 512
3 => (y % 512 / 8) * 0x40 + (x % 512 / 8) * 2, // 512 x 512
0 => (x % 256 / 8) * 2 + (y % 256 / 8) * 0x40, // 256 x 256
1 => blk: {
// 512 x 256
const offset: u32 = if (x & 0x1FF > 0xFF) 0x800 else 0;
break :blk offset + (x % 256 / 8) * 2 + (y % 256 / 8) * 0x40;
},
2 => blk: {
// 256 x 512
const offset: u32 = if (y & 0x1FF > 0xFF) 0x800 else 0;
break :blk offset + (x % 256 / 8) * 2 + (y % 256 / 8) * 0x40;
},
3 => blk: {
// 512 x 512
const offset: u32 = if (x & 0x1FF > 0xFF) 0x800 else 0;
const offset_2: u32 = if (y & 0x1FF > 0xFF) 0x800 else 0;
break :blk offset + offset_2 + (x % 256 / 8) * 2 + (y % 512 / 8) * 0x40;
},
};
}
};