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feat: implement mode 5 

I wonder which obscure game makes heavy use of this mode
This commit is contained in:
Rekai Nyangadzayi Musuka 2022-10-21 05:12:40 -03:00
parent f1c68fb0de
commit 192d7645eb
1 changed files with 31 additions and 17 deletions
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48
src/ppu.zig
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@ -281,31 +281,30 @@ pub const Ppu = struct {
const fb_base = framebuf_pitch * @as(usize, scanline); const fb_base = framebuf_pitch * @as(usize, scanline);
if (obj_enable) self.fetchSprites(); if (obj_enable) self.fetchSprites();
var i: usize = 0; var layer: usize = 0;
while (i < 4) : (i += 1) { while (layer < 4) : (layer += 1) {
// Draw Sprites Here self.drawSprites(@truncate(u2, layer));
self.drawSprites(@truncate(u2, i)); if (layer == self.bg[0].cnt.priority.read() and bg_enable & 1 == 1) self.drawBackround(0);
if (i == self.bg[0].cnt.priority.read() and bg_enable & 1 == 1) self.drawBackround(0); if (layer == self.bg[1].cnt.priority.read() and bg_enable >> 1 & 1 == 1) self.drawBackround(1);
if (i == self.bg[1].cnt.priority.read() and bg_enable >> 1 & 1 == 1) self.drawBackround(1); if (layer == self.bg[2].cnt.priority.read() and bg_enable >> 2 & 1 == 1) self.drawBackround(2);
if (i == self.bg[2].cnt.priority.read() and bg_enable >> 2 & 1 == 1) self.drawBackround(2); if (layer == self.bg[3].cnt.priority.read() and bg_enable >> 3 & 1 == 1) self.drawBackround(3);
if (i == self.bg[3].cnt.priority.read() and bg_enable >> 3 & 1 == 1) self.drawBackround(3);
} }
// Copy Drawn Scanline to Frame Buffer // Copy Drawn Scanline to Frame Buffer
// If there are any nulls present in self.scanline_buf it means that no background drew a pixel there, so draw backdrop // If there are any nulls present in self.scanline_buf it means that no background drew a pixel there, so draw backdrop
for (self.scanline_buf) |maybe_px, j| { for (self.scanline_buf) |maybe_px, i| {
const bgr555 = if (maybe_px) |px| px else self.palette.getBackdrop(); const bgr555 = if (maybe_px) |px| px else self.palette.getBackdrop();
std.mem.copy(u8, self.framebuf[fb_base + j * @sizeOf(u32) ..][0..4], &intToBytes(u32, toRgba8888(bgr555))); std.mem.copy(u8, self.framebuf[fb_base + i * @sizeOf(u32) ..][0..4], &intToBytes(u32, toRgba8888(bgr555)));
} }
// Reset Scanline Buffer // Reset Current Scanline Pixel Buffer and list of fetched sprites
// in prep for next scanline
std.mem.set(?u16, &self.scanline_buf, null); std.mem.set(?u16, &self.scanline_buf, null);
// Reset List of Sprites
std.mem.set(?Sprite, &self.scanline_sprites, null); std.mem.set(?Sprite, &self.scanline_sprites, null);
}, },
0x3 => { 0x3 => {
const fb_base = framebuf_pitch * @as(usize, scanline);
const vram_base = width * @sizeOf(u16) * @as(usize, scanline); const vram_base = width * @sizeOf(u16) * @as(usize, scanline);
const fb_base = framebuf_pitch * @as(usize, scanline);
var i: usize = 0; var i: usize = 0;
while (i < width) : (i += 1) { while (i < width) : (i += 1) {
@ -314,14 +313,29 @@ pub const Ppu = struct {
} }
}, },
0x4 => { 0x4 => {
const select = self.dispcnt.frame_select.read(); const sel = self.dispcnt.frame_select.read();
const vram_base = width * @as(usize, scanline) + if (sel) 0xA000 else @as(usize, 0);
const fb_base = framebuf_pitch * @as(usize, scanline); const fb_base = framebuf_pitch * @as(usize, scanline);
const vram_base = width * @as(usize, scanline) + if (select) 0xA000 else @as(usize, 0);
// Render Current Scanline // Render Current Scanline
for (self.vram.buf[vram_base .. vram_base + width]) |byte, i| { for (self.vram.buf[vram_base .. vram_base + width]) |byte, i| {
const pal_id = @as(u16, byte) * @sizeOf(u16); const bgr555 = self.palette.read(u16, @as(u16, byte) * @sizeOf(u16));
const bgr555 = self.palette.read(u16, pal_id); std.mem.copy(u8, self.framebuf[fb_base + i * @sizeOf(u32) ..][0..4], &intToBytes(u32, toRgba8888(bgr555)));
}
},
0x5 => {
const m5_width = 160;
const m5_height = 128;
const sel = self.dispcnt.frame_select.read();
const vram_base = m5_width * @sizeOf(u16) * @as(usize, scanline) + if (sel) 0xA000 else @as(usize, 0);
const fb_base = framebuf_pitch * @as(usize, scanline);
var i: usize = 0;
while (i < width) : (i += 1) {
// If we're outside of the bounds of mode 5, draw the background colour
const bgr555 =
if (scanline < m5_height and i < m5_width) self.vram.read(u16, vram_base + i * @sizeOf(u16)) else self.palette.getBackdrop();
std.mem.copy(u8, self.framebuf[fb_base + i * @sizeOf(u32) ..][0..4], &intToBytes(u32, toRgba8888(bgr555))); std.mem.copy(u8, self.framebuf[fb_base + i * @sizeOf(u32) ..][0..4], &intToBytes(u32, toRgba8888(bgr555)));
} }