diff options
Diffstat (limited to 'src/ppu.rs')
| -rw-r--r-- | src/ppu.rs | 78 |
1 files changed, 35 insertions, 43 deletions
@@ -57,11 +57,13 @@ pub struct PPU<'a> { impl<'a> PPU<'a> { pub fn write_ctl(&mut self, data: u8) { + self.reg = data; self.ppuctl = data; self.t = (self.t & 0x73ff) | ((data as u16 & 3) << 10); } pub fn write_mask(&mut self, data: u8) { + self.reg = data; self.ppumask = data; } @@ -73,10 +75,12 @@ impl<'a> PPU<'a> { } pub fn write_oamaddr(&mut self, data: u8) { + self.reg = data; self.oamaddr = data; } pub fn write_oamdata(&mut self, data: u8) { + self.reg = data; if self.rendering { return } unsafe { let oam_raw = transmute::<&mut[Sprite; 64], &mut[u8; 256]>(&mut self.oam); @@ -93,6 +97,7 @@ impl<'a> PPU<'a> { } pub fn write_scroll(&mut self, data: u8) { + self.reg = data; let data = data as u16; match self.w { false => { @@ -109,6 +114,7 @@ impl<'a> PPU<'a> { } pub fn write_addr(&mut self, data: u8) { + self.reg = data; let data = data as u16; match self.w { false => { @@ -141,6 +147,7 @@ impl<'a> PPU<'a> { } pub fn write_data(&mut self, data: u8) { + self.reg = data; self.mem.write(self.v, data); self.v = self.v.wrapping_add(match self.get_vram_inc() { 0 => 1, @@ -149,6 +156,7 @@ impl<'a> PPU<'a> { } pub fn write_oamdma(&mut self, data: u8, cpu: &mut CPU) { + self.reg = data; let mut addr = (data as u16) << 8; unsafe { let oam_raw = transmute::<&mut[Sprite; 64], &mut[u8; 256]>(&mut self.oam); @@ -217,10 +225,10 @@ impl<'a> PPU<'a> { // self.bg_palette[0] >> 8 == 0 && // self.bg_palette[1] >> 8 == 0)) { // println!("at cycle {} {}", self.scanline, self.cycle) } - //assert!(self.bg_bitmap[0] >> 8 == 0 && - // self.bg_bitmap[1] >> 8 == 0 && - // self.bg_palette[0] >> 8 == 0 && - // self.bg_palette[1] >> 8 == 0); + assert!(self.bg_bitmap[0] >> 8 == 0 && + self.bg_bitmap[1] >> 8 == 0 && + self.bg_palette[0] >> 8 == 0 && + self.bg_palette[1] >> 8 == 0); self.bg_bitmap[0] |= (PPU::reverse_byte(self.bg_bit_low) as u16) << 8; self.bg_bitmap[1] |= (PPU::reverse_byte(self.bg_bit_high) as u16) << 8; self.bg_palette[0] |= (self.bg_attr & 1) as u16 * 0xff00; @@ -244,13 +252,13 @@ impl<'a> PPU<'a> { } #[inline(always)] - fn shift_bgtile(&mut self, d: u8) { + fn shift_bgtile(&mut self) { let t1 = &mut self.bg_bitmap; let t2 = &mut self.bg_palette; - t1[0] = t1[0].wrapping_shr(d as u32); - t1[1] = t1[1].wrapping_shr(d as u32); - t2[0] = t2[0].wrapping_shr(d as u32); - t2[1] = t2[1].wrapping_shr(d as u32); + t1[0] = t1[0].wrapping_shr(1); + t1[1] = t1[1].wrapping_shr(1); + t2[0] = t2[0].wrapping_shr(1); + t2[1] = t2[1].wrapping_shr(1); } #[inline(always)] @@ -292,10 +300,12 @@ impl<'a> PPU<'a> { #[inline(always)] fn clear_sprite(&mut self) { + if self.scanline == 261 { return } self.oam2 = [0x100; 8]; } fn eval_sprite(&mut self) { + if self.scanline == 261 { return } /* we use scanline here because s.y is the (actual y) - 1 */ let mut nidx = 0; let mut n = 0; @@ -341,6 +351,7 @@ impl<'a> PPU<'a> { } fn fetch_sprite(&mut self) { + if self.scanline == 261 { return } /* we use scanline here because s.y is the (actual y) - 1 */ self.sp_idx = [0x100; 8]; for (i, v) in self.oam2.iter().enumerate() { @@ -483,9 +494,9 @@ impl<'a> PPU<'a> { self.cycle = cycle + 1; return false; } - let visible = self.scanline < 240; + let visible_line = self.scanline < 240; let pre_render = self.scanline == 261; - self.rendering = pre_render || visible; + self.rendering = pre_render || visible_line; if pre_render && cycle == 1 { /* clear vblank, sprite zero hit & overflow */ self.ppustatus &= !(PPU::FLAG_VBLANK | @@ -495,14 +506,16 @@ impl<'a> PPU<'a> { if pre_render && 279 < cycle && cycle < 305 { self.reset_y(); } else { - let shifting = 0 < cycle && cycle < 257; /* 1..256 */ - let fetch = shifting || (320 < cycle && cycle < 337); - if fetch { /* 1..256 and 321..336 */ + let visible_cycle = 0 < cycle && cycle < 257; /* 1..256 */ + let fetch_cycle = visible_cycle || (320 < cycle && cycle < 337); + if visible_line && visible_cycle { + self.render_pixel(); + self.shift_sprites(); + } + if fetch_cycle { /* 1..256 and 321..336 */ match cycle & 0x7 { 1 => { - if shifting && cycle > 1 { - self.load_bgtile(); - } + self.load_bgtile(); self.fetch_nametable_byte(); }, 3 => self.fetch_attrtable_byte(), @@ -511,26 +524,15 @@ impl<'a> PPU<'a> { 0 => self.wrapping_inc_cx(), _ => () } - if visible { - match cycle { - 1 => self.clear_sprite(), /* clear secondary OAM */ - 65 => self.eval_sprite(), /* sprite evaluation */ - _ => () - } - } match cycle { - 256 => { - self.wrapping_inc_y() - }, - 329 => self.load_bgtile(), + 1 => self.clear_sprite(), /* clear secondary OAM */ + 65 => self.eval_sprite(), /* sprite evaluation */ + 256 => self.wrapping_inc_y(), _ => () } + self.shift_bgtile(); } else if cycle > 336 { /* 337..340 */ if cycle & 1 == 1 { - if cycle == 337 { - self.shift_bgtile(8); - self.load_bgtile(); - } self.fetch_nametable_byte(); } } else if cycle == 257 { @@ -538,17 +540,7 @@ impl<'a> PPU<'a> { * from the secondary OAM which is not subject to any change during this * scanline */ self.reset_cx(); - if visible { - self.fetch_sprite(); - } - } - - if shifting { - if visible { - self.render_pixel(); - } - self.shift_bgtile(1); - self.shift_sprites(); + self.fetch_sprite(); } } } else if self.scanline == 241 && cycle == 1 { |