chore: separate render code for affine sprites
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8d32d9788e
commit
d3bc58d71c
130
src/ppu.zig
130
src/ppu.zig
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@ -132,16 +132,16 @@ pub const Ppu = struct {
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if (maybe_sprite) |sprite| {
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// Skip this sprite if it isn't on the current priority
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if (sprite.priority() != layer) continue;
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if (sprite.attr0.is_affine.read()) self.drawSprite(sprite) else self.drawSprite(sprite);
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if (sprite.attr0.is_affine.read()) self.drawAffineSprite(AffineSprite.from(sprite)) else self.drawSprite(sprite);
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} else break;
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}
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}
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fn drawSprite(self: *Self, sprite: Sprite) void {
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fn drawAffineSprite(self: *Self, sprite: AffineSprite) void {
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const iy = @bitCast(i8, self.vcount.scanline.read());
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const is_8bpp = sprite.is_8bpp();
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const tile_id: u32 = sprite.tile_id();
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const is_8bpp = sprite.is8bpp();
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const tile_id: u32 = sprite.tileId();
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const obj_mapping = self.dispcnt.obj_mapping.read();
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const tile_row_offset: u32 = if (is_8bpp) 8 else 4;
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const tile_len: u32 = if (is_8bpp) 0x40 else 0x20;
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@ -165,14 +165,8 @@ pub const Ppu = struct {
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// Sprite is within bounds and therefore should be rendered
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// std.math.absInt is branchless
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const x_diff = @bitCast(u9, std.math.absInt(ix - isprite_start) catch unreachable);
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const y_diff = @bitCast(u8, std.math.absInt(iy -% @bitCast(i8, sprite.y())) catch unreachable);
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// Note that we flip the tile_pos not the (tile_pos % 8) like we do for
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// Background Tiles. By doing this we mirror the entire sprite instead of
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// just a specific tile (see how sprite.width and sprite.height are involved)
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const tile_y = y_diff ^ if (sprite.v_flip()) (sprite.height - 1) else 0;
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const tile_x = x_diff ^ if (sprite.h_flip()) (sprite.width - 1) else 0;
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const tile_x = @bitCast(u9, std.math.absInt(ix - @bitCast(i9, sprite.x())) catch unreachable);
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const tile_y = @bitCast(u8, std.math.absInt(iy -% @bitCast(i8, sprite.y())) catch unreachable);
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const row = @truncate(u3, tile_y);
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const col = @truncate(u3, tile_x);
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@ -183,7 +177,60 @@ pub const Ppu = struct {
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const tile_offset = (tile_x >> 3) * tile_len + (tile_y >> 3) * tile_len * mapping_offset;
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const tile = self.vram.buf[tile_base + tile_offset];
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const pal_id: u16 = if (!is_8bpp) get4bppTilePalette(sprite.pal_bank(), col, tile) else tile;
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const pal_id: u16 = if (!is_8bpp) get4bppTilePalette(sprite.palBank(), col, tile) else tile;
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// Sprite Palette starts at 0x0500_0200
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if (pal_id != 0) self.scanline_buf[x] = self.palette.read(u16, 0x200 + pal_id * 2);
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}
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}
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fn drawSprite(self: *Self, sprite: Sprite) void {
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const iy = @bitCast(i8, self.vcount.scanline.read());
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const is_8bpp = sprite.is8bpp();
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const tile_id: u32 = sprite.tileId();
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const obj_mapping = self.dispcnt.obj_mapping.read();
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const tile_row_offset: u32 = if (is_8bpp) 8 else 4;
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const tile_len: u32 = if (is_8bpp) 0x40 else 0x20;
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const char_base = 0x4000 * 4;
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var i: u9 = 0;
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while (i < sprite.width) : (i += 1) {
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const x = (sprite.x() +% i) % width;
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const ix = @bitCast(i9, x);
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if (self.scanline_buf[x] != null) continue;
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const sprite_start = sprite.x();
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const isprite_start = @bitCast(i9, sprite_start);
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const sprite_end = sprite_start +% sprite.width;
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const isprite_end = @bitCast(i9, sprite_end);
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const condition = (sprite_start <= x and x < sprite_end) or (isprite_start <= ix and ix < isprite_end);
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if (!condition) continue;
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// Sprite is within bounds and therefore should be rendered
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// std.math.absInt is branchless
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const x_diff = @bitCast(u9, std.math.absInt(ix - @bitCast(i9, sprite.x())) catch unreachable);
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const y_diff = @bitCast(u8, std.math.absInt(iy -% @bitCast(i8, sprite.y())) catch unreachable);
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// Note that we flip the tile_pos not the (tile_pos % 8) like we do for
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// Background Tiles. By doing this we mirror the entire sprite instead of
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// just a specific tile (see how sprite.width and sprite.height are involved)
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const tile_y = y_diff ^ if (sprite.vFlip()) (sprite.height - 1) else 0;
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const tile_x = x_diff ^ if (sprite.hFlip()) (sprite.width - 1) else 0;
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const row = @truncate(u3, tile_y);
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const col = @truncate(u3, tile_x);
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// TODO: Finish that 2D Sprites Test ROM
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const tile_base = char_base + (tile_id * 0x20) + (row * tile_row_offset) + if (is_8bpp) col else col >> 1;
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const mapping_offset = if (obj_mapping) sprite.width >> 3 else if (is_8bpp) @as(u32, 0x10) else 0x20;
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const tile_offset = (tile_x >> 3) * tile_len + (tile_y >> 3) * tile_len * mapping_offset;
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const tile = self.vram.buf[tile_base + tile_offset];
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const pal_id: u16 = if (!is_8bpp) get4bppTilePalette(sprite.palBank(), col, tile) else tile;
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// Sprite Palette starts at 0x0500_0200
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if (pal_id != 0) self.scanline_buf[x] = self.palette.read(u16, 0x200 + pal_id * 2);
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@ -760,31 +807,23 @@ const Sprite = struct {
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return self.attr0.y.read();
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}
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fn is_8bpp(self: *const Self) bool {
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fn is8bpp(self: *const Self) bool {
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return self.attr0.is_8bpp.read();
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}
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fn shape(self: *const Self) u2 {
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return self.attr0.shape.read();
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}
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fn size(self: *const Self) u2 {
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return self.attr1.size.read();
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}
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fn tile_id(self: *const Self) u10 {
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fn tileId(self: *const Self) u10 {
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return self.attr2.tile_id.read();
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}
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fn pal_bank(self: *const Self) u4 {
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fn palBank(self: *const Self) u4 {
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return self.attr2.pal_bank.read();
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}
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fn h_flip(self: *const Self) bool {
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fn hFlip(self: *const Self) bool {
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return self.attr1.h_flip.read();
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}
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fn v_flip(self: *const Self) bool {
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fn vFlip(self: *const Self) bool {
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return self.attr1.v_flip.read();
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}
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@ -803,17 +842,39 @@ const AffineSprite = struct {
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width: u8,
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height: u8,
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fn init(attr0: AffineAttr0, attr1: AffineAttr1, attr2: Attr2) Self {
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const d = spriteDimensions(attr0.shape.read(), attr1.size.read());
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fn from(sprite: Sprite) AffineSprite {
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return .{
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.attr0 = attr0,
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.attr1 = attr1,
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.attr2 = attr2,
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.width = d[0],
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.height = d[1],
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.attr0 = .{ .raw = sprite.attr0.raw },
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.attr1 = .{ .raw = sprite.attr1.raw },
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.attr2 = sprite.attr2,
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.width = sprite.width,
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.height = sprite.height,
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};
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}
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fn x(self: *const Self) u9 {
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return self.attr1.x.read();
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}
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fn y(self: *const Self) u8 {
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return self.attr0.y.read();
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}
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fn is8bpp(self: *const Self) bool {
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return self.attr0.is_8bpp.read();
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}
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fn tileId(self: *const Self) u10 {
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return self.attr2.tile_id.read();
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}
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fn palBank(self: *const Self) u4 {
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return self.attr2.pal_bank.read();
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}
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fn matrixId(self: *const Self) u5 {
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return self.attr1.aff_sel.read();
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}
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};
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const Attr0 = extern union {
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@ -857,6 +918,7 @@ const Attr2 = extern union {
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tile_id: Bitfield(u16, 0, 10),
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rel_prio: Bitfield(u16, 10, 2),
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pal_bank: Bitfield(u16, 12, 4),
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raw: u16,
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};
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fn spriteDimensions(shape: u2, size: u2) [2]u8 {
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