diff options
Diffstat (limited to 'src/nes/ppu.cc')
| -rw-r--r-- | src/nes/ppu.cc | 66 |
1 files changed, 44 insertions, 22 deletions
diff --git a/src/nes/ppu.cc b/src/nes/ppu.cc index 003c3d6..29a5643 100644 --- a/src/nes/ppu.cc +++ b/src/nes/ppu.cc @@ -50,12 +50,10 @@ namespace nes scanline_cycle_ = 0; scanline_ += 1; - if (scanline_ == 261) + if (scanline_ == 262) { scanline_ = 0; even_frame_ = !even_frame_; - - display_.switch_buffers(); } } @@ -76,6 +74,7 @@ namespace nes if (render_line && fetch_cycle) { + tile_data_ <<= 4; switch (scanline_cycle_ % 8) { case 1: @@ -139,6 +138,7 @@ namespace nes // Vblank Logic if (scanline_ == 241 && scanline_cycle_ == 1) { + display_.switch_buffers(); status_.vblank = true; nmi_change(); } @@ -146,7 +146,7 @@ namespace nes { status_.vblank = false; nmi_change(); - status_.sprite_0_hit = false; + status_.sprite_zero_hit = false; status_.sprite_overflow = false; } } @@ -180,11 +180,12 @@ namespace nes break; } - if (x < 8 && !mask_.show_background_start) { background_color = color_index{ 0 }; } - if (x < 8 && !mask_.show_sprites_start) { foreground_color = color_index{ 0 }; } + auto has_background = background_color.color != 0; + auto has_foreground = foreground_color.color != 0; + + if (x < 8 && !mask_.show_background_start) { has_background = false; } + if (x < 8 && !mask_.show_sprites_start) { has_foreground = false; } - auto const has_background = background_color.color != 0; - auto const has_foreground = foreground_color.color != 0; auto color = color_index{ 0 }; if (!has_background && has_foreground) { @@ -198,7 +199,7 @@ namespace nes { if (foreground.is_sprite_zero && x < 255) { - status_.sprite_0_hit = true; + status_.sprite_zero_hit = true; } color = foreground.is_in_front ? foreground_color : background_color; @@ -236,7 +237,7 @@ namespace nes auto const table = control_.background_pattern_table; auto const tile = name_table_byte_; auto const addr = static_cast<std::uint16_t>(0x1000 * table + 16 * tile + fine_y); - low_tile_byte_ = read8(address{ addr } + 8); + high_tile_byte_ = read8(address{ addr } + 8); } auto ppu::store_tile_data() -> void @@ -251,7 +252,6 @@ namespace nes data <<= 4; data |= attribute_table_byte_ | p1 | p2; } - tile_data_ <<= 32; tile_data_ |= data; } @@ -261,7 +261,9 @@ namespace nes if ((internal_.v & 0x1F) == 0x1F) { // Coarse X = 0 - internal_.v &= ~0x1F; + // TODO: Check + // internal_.v &= ~0x1F; + internal_.v &= 0xFFE0; // Switch horizontal nametable internal_.v ^= 0x400; } @@ -299,7 +301,9 @@ namespace nes y += 1; } // Put coarse Y back into v - internal_.v &= ~0x03E0; + // TODO: Check + // internal_.v &= ~0x03E0; + internal_.v &= 0xFC1F; internal_.v |= y << 5; } else @@ -335,7 +339,9 @@ namespace nes { sprites_[sprite_count_].pattern = fetch_sprite_pattern(i, row); sprites_[sprite_count_].position = x; - sprites_[sprite_count_].is_in_front = a & 0b00100000; + // TODO: Check + // sprites_[sprite_count_].is_in_front = a & 0b00100000; + sprites_[sprite_count_].is_in_front = (a >> 5) & 1; sprites_[sprite_count_].is_sprite_zero = i == 0; sprite_count_ += 1; } @@ -383,10 +389,21 @@ namespace nes for (auto j = unsigned{ 0 }; j < 8; ++j) { auto const flip_horizontal = (attributes & 0x40) == 0x40; - auto const p1 = flip_horizontal ? (low_tile_byte & 1) << 0 : (low_tile_byte & 0x80) >> 7; - auto const p2 = flip_horizontal ? (high_tile_byte & 1) << 1 : (high_tile_byte & 0x80) >> 6; - low_tile_byte <<= 1; - high_tile_byte <<= 1; + std::uint8_t p1, p2; + if (flip_horizontal) + { + p1 = (low_tile_byte & 1) << 0; + p2 = (high_tile_byte & 1) << 1; + low_tile_byte >>= 1; + high_tile_byte >>= 1; + } + else + { + p1 = (low_tile_byte & 0x80) >> 7; + p2 = (high_tile_byte & 0x80) >> 6; + low_tile_byte <<= 1; + high_tile_byte <<= 1; + } data <<= 4; data |= a | p1 | p2; } @@ -454,13 +471,17 @@ namespace nes internal_.w = false; nmi_change(); - write_latch(res); + //write_latch(res); return res; } auto ppu::read_oamdata() -> std::uint8_t { - auto const res = oam_[oamaddr_]; + auto res = oam_[oamaddr_]; + if ((oamaddr_ & 0x3) == 0x2) + { + res &= 0xE3; + } write_latch(res); return res; } @@ -470,7 +491,7 @@ namespace nes auto const addr = address{ internal_.v }; auto res = read8(addr); - if (addr <= address{ 0x3F00 }) + if (addr % 0x4000 <= address{ 0x3F00 }) { std::swap(res, ppudata_read_buffer_); } @@ -496,6 +517,7 @@ namespace nes if (current_cycles_ > boot_up_cycles) { control_.value = value; + internal_.t = (internal_.t & 0xF3FF) | ((value & 0x03) << 10); nmi_change(); } } @@ -539,7 +561,7 @@ namespace nes if (!internal_.w) { // First write. - internal_.t = (internal_.t & 0b0000000011111111) | ((value & 0b00111111) << 8); + internal_.t = (internal_.t & 0b1000000011111111) | ((value & 0b00111111) << 8); } else { |