chore(ppu): use @ptrCast in drawTextMode

window wrap now works (it's pretty slow though?)

.github/workflows/main.yml

@@ -17,7 +17,7 @@ jobs:
         os: [ubuntu-latest, windows-latest, macos-latest]
     runs-on: ${{matrix.os}}
     steps:
-      - uses: goto-bus-stop/setup-zig@v1
+      - uses: goto-bus-stop/setup-zig@v2
         with:
           version: master
       - name: prepare-linux
@@ -51,7 +51,7 @@ jobs:
       - uses: actions/checkout@v3
         with:
           submodules: true
-      - uses: goto-bus-stop/setup-zig@v1
+      - uses: goto-bus-stop/setup-zig@v2
         with:
           version: master
       - run: zig fmt src/**/*.zig

src/core/bus/backup.zig

@@ -6,7 +6,6 @@ const Eeprom = @import("backup/eeprom.zig").Eeprom;
 const Flash = @import("backup/Flash.zig");
 
 const escape = @import("../../util.zig").escape;
-const span = @import("../../util.zig").span;
 
 const Needle = struct { str: []const u8, kind: Backup.Kind };
 const backup_kinds = [6]Needle{
@@ -195,7 +194,7 @@ pub const Backup = struct {
     }
 
     fn saveName(self: *const Self, allocator: Allocator) ![]const u8 {
-        const title_str = span(&escape(self.title));
+        const title_str = std.mem.sliceTo(&escape(self.title), 0);
         const name = if (title_str.len != 0) title_str else "untitled";
 
         return try std.mem.concat(allocator, u8, &[_][]const u8{ name, ".sav" });

src/core/ppu.zig

@@ -573,7 +573,7 @@ pub const Ppu = struct {
 
         switch (bg_mode) {
             0x0 => {
-                const fb_base = framebuf_pitch * @as(usize, scanline);
+                const framebuf_base = width * @as(usize, scanline);
                 if (obj_enable) self.fetchSprites();
 
                 var layer: usize = 0;
@@ -585,23 +585,10 @@ pub const Ppu = struct {
                     if (layer == self.bg[3].cnt.priority.read() and bg_enable >> 3 & 1 == 1) self.drawBackground(3);
                 }
 
-                // Copy Drawn Scanline to Frame Buffer
+                self.drawTextMode(framebuf_base);
-                // If there are any nulls present in self.scanline it means that no background drew a pixel there, so draw backdrop
-                for (self.scanline.top()) |maybe_px, i| {
-                    const maybe_top = maybe_px;
-                    const maybe_btm = self.scanline.btm()[i];
-
-                    const bgr555 = self.getBgr555(maybe_top, maybe_btm);
-                    std.mem.writeIntNative(u32, self.framebuf.get(.Emulator)[fb_base + i * @sizeOf(u32) ..][0..@sizeOf(u32)], rgba888(bgr555));
-                }
-
-                // Reset Current Scanline Pixel Buffer and list of fetched sprites
-                // in prep for next scanline
-                self.scanline.reset();
-                std.mem.set(?Sprite, self.scanline_sprites, null);
             },
             0x1 => {
-                const fb_base = framebuf_pitch * @as(usize, scanline);
+                const framebuf_base = width * @as(usize, scanline);
                 if (obj_enable) self.fetchSprites();
 
                 var layer: usize = 0;
@@ -612,23 +599,10 @@ pub const Ppu = struct {
                     if (layer == self.bg[2].cnt.priority.read() and bg_enable >> 2 & 1 == 1) self.drawAffineBackground(2);
                 }
 
-                // Copy Drawn Scanline to Frame Buffer
+                self.drawTextMode(framebuf_base);
-                // If there are any nulls present in self.scanline.top() it means that no background drew a pixel there, so draw backdrop
-                for (self.scanline.top()) |maybe_px, i| {
-                    const maybe_top = maybe_px;
-                    const maybe_btm = self.scanline.btm()[i];
-
-                    const bgr555 = self.getBgr555(maybe_top, maybe_btm);
-                    std.mem.writeIntNative(u32, self.framebuf.get(.Emulator)[fb_base + i * @sizeOf(u32) ..][0..@sizeOf(u32)], rgba888(bgr555));
-                }
-
-                // Reset Current Scanline Pixel Buffer and list of fetched sprites
-                // in prep for next scanline
-                self.scanline.reset();
-                std.mem.set(?Sprite, self.scanline_sprites, null);
             },
             0x2 => {
-                const fb_base = framebuf_pitch * @as(usize, scanline);
+                const framebuf_base = width * @as(usize, scanline);
                 if (obj_enable) self.fetchSprites();
 
                 var layer: usize = 0;
@@ -638,40 +612,32 @@ pub const Ppu = struct {
                     if (layer == self.bg[3].cnt.priority.read() and bg_enable >> 3 & 1 == 1) self.drawAffineBackground(3);
                 }
 
-                // Copy Drawn Scanline to Frame Buffer
+                self.drawTextMode(framebuf_base);
-                // If there are any nulls present in self.scanline.top() it means that no background drew a pixel there, so draw backdrop
-                for (self.scanline.top()) |maybe_px, i| {
-                    const maybe_top = maybe_px;
-                    const maybe_btm = self.scanline.btm()[i];
-
-                    const bgr555 = self.getBgr555(maybe_top, maybe_btm);
-                    std.mem.writeIntNative(u32, self.framebuf.get(.Emulator)[fb_base + i * @sizeOf(u32) ..][0..@sizeOf(u32)], rgba888(bgr555));
-                }
-
-                // Reset Current Scanline Pixel Buffer and list of fetched sprites
-                // in prep for next scanline
-                self.scanline.reset();
-                std.mem.set(?Sprite, self.scanline_sprites, null);
             },
             0x3 => {
-                const vram_base = width * @sizeOf(u16) * @as(usize, scanline);
+                const vram_base = width * @as(usize, scanline);
-                const fb_base = framebuf_pitch * @as(usize, scanline);
+                const framebuf_base = width * @as(usize, scanline);
 
-                var i: usize = 0;
+                // FIXME: @ptrCast between slices changing the length isn't implemented yet
-                while (i < width) : (i += 1) {
+                const vram_buf = @ptrCast([*]const u16, @alignCast(@alignOf(u16), self.vram.buf));
-                    const bgr555 = self.vram.read(u16, vram_base + i * @sizeOf(u16));
+                const framebuf = @ptrCast([*]u32, @alignCast(@alignOf(u32), self.framebuf.get(.Emulator)));
-                    std.mem.writeIntNative(u32, self.framebuf.get(.Emulator)[fb_base + i * @sizeOf(u32) ..][0..@sizeOf(u32)], rgba888(bgr555));
+
+                for (vram_buf[vram_base .. vram_base + width]) |bgr555, i| {
+                    framebuf[framebuf_base + i] = rgba888(bgr555);
                 }
             },
             0x4 => {
                 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);
 
-                // Render Current Scanline
+                const vram_base = width * @as(usize, scanline) + if (sel) 0xA000 else @as(usize, 0);
-                for (self.vram.buf[vram_base .. vram_base + width]) |byte, i| {
+                const framebuf_base = width * @as(usize, scanline);
-                    const bgr555 = self.palette.read(u16, @as(u16, byte) * @sizeOf(u16));
+
-                    std.mem.writeIntNative(u32, self.framebuf.get(.Emulator)[fb_base + i * @sizeOf(u32) ..][0..@sizeOf(u32)], rgba888(bgr555));
+                // FIXME: @ptrCast between slices changing the length isn't implemented yet
+                const pal_buf = @ptrCast([*]const u16, @alignCast(@alignOf(u16), self.palette.buf));
+                const framebuf = @ptrCast([*]u32, @alignCast(@alignOf(u32), self.framebuf.get(.Emulator)));
+
+                for (self.vram.buf[vram_base .. vram_base + width]) |pal_id, i| {
+                    framebuf[framebuf_base + i] = rgba888(pal_buf[pal_id]);
                 }
             },
             0x5 => {
@@ -679,22 +645,44 @@ pub const Ppu = struct {
                 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 vram_base = m5_width * @as(usize, scanline) + if (sel) 0xA000 else @as(usize, 0);
-                const fb_base = framebuf_pitch * @as(usize, scanline);
+                const framebuf_base = width * @as(usize, scanline);
+
+                // FIXME: @ptrCast between slices changing the length isn't implemented yet
+                const vram_buf = @ptrCast([*]const u16, @alignCast(@alignOf(u16), self.vram.buf));
+                const framebuf = @ptrCast([*]u32, @alignCast(@alignOf(u32), self.framebuf.get(.Emulator)));
 
                 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) vram_buf[vram_base + i] else self.palette.backdrop();
-                    const bgr555 =
+                    framebuf[framebuf_base + i] = rgba888(bgr555);
-                        if (scanline < m5_height and i < m5_width) self.vram.read(u16, vram_base + i * @sizeOf(u16)) else self.palette.backdrop();
-
-                    std.mem.writeIntNative(u32, self.framebuf.get(.Emulator)[fb_base + i * @sizeOf(u32) ..][0..@sizeOf(u32)], rgba888(bgr555));
                 }
             },
             else => std.debug.panic("[PPU] TODO: Implement BG Mode {}", .{bg_mode}),
         }
     }
 
+    fn drawTextMode(self: *Self, framebuf_base: usize) void {
+        // Copy Drawn Scanline to Frame Buffer
+        // If there are any nulls present in self.scanline.top() it means that no background drew a pixel there, so draw backdrop
+
+        // FIXME: @ptrCast between slices changing the length isn't implemented yet
+        const framebuf = @ptrCast([*]u32, @alignCast(@alignOf(u32), self.framebuf.get(.Emulator)));
+
+        for (self.scanline.top()) |maybe_px, i| {
+            const maybe_top = maybe_px;
+            const maybe_btm = self.scanline.btm()[i];
+
+            const bgr555 = self.getBgr555(maybe_top, maybe_btm);
+            framebuf[framebuf_base + i] = rgba888(bgr555);
+        }
+
+        // Reset Current Scanline Pixel Buffer and list of fetched sprites
+        // in prep for next scanline
+        self.scanline.reset();
+        std.mem.set(?Sprite, self.scanline_sprites, null);
+    }
+
     fn getBgr555(self: *Self, maybe_top: ?u16, maybe_btm: ?u16) u16 {
         if (maybe_btm) |btm| {
             return switch (self.bld.cnt.mode.read()) {

src/core/ppu/Palette.zig

@@ -42,6 +42,6 @@ pub fn deinit(self: *Self) void {
     self.* = undefined;
 }
 
-pub fn backdrop(self: *const Self) u16 {
+pub inline fn backdrop(self: *const Self) u16 {
-    return self.read(u16, 0);
+    return std.mem.readIntNative(u16, self.buf[0..2]);
 }

src/platform.zig

@@ -9,8 +9,6 @@ const Arm7tdmi = @import("core/cpu.zig").Arm7tdmi;
 const Scheduler = @import("core/scheduler.zig").Scheduler;
 const FpsTracker = @import("util.zig").FpsTracker;
 
-const span = @import("util.zig").span;
-
 const gba_width = @import("core/ppu.zig").width;
 const gba_height = @import("core/ppu.zig").height;
 
@@ -73,7 +71,7 @@ pub const Gui = struct {
 
         return Self{
             .window = window,
-            .title = span(title),
+            .title = std.mem.sliceTo(title, 0),
             .ctx = ctx,
             .program_id = program_id,
             .audio = Audio.init(apu),

src/util.zig

@@ -68,57 +68,6 @@ pub fn intToBytes(comptime T: type, value: anytype) [@sizeOf(T)]u8 {
     return result;
 }
 
-/// The Title from the GBA Cartridge is an Uppercase ASCII string which is
-/// null-padded to 12 bytes
-///
-/// This function returns a slice of the ASCII string without the null terminator(s)
-/// (essentially, a proper Zig/Rust/Any modern language String)
-pub fn span(title: *const [12]u8) []const u8 {
-    const end = std.mem.indexOfScalar(u8, title, '\x00');
-    return title[0 .. end orelse title.len];
-}
-
-test "span" {
-    var example: *const [12]u8 = "POKEMON_EMER";
-    try std.testing.expectEqualSlices(u8, "POKEMON_EMER", span(example));
-
-    example = "POKEMON_EME\x00";
-    try std.testing.expectEqualSlices(u8, "POKEMON_EME", span(example));
-
-    example = "POKEMON_EM\x00\x00";
-    try std.testing.expectEqualSlices(u8, "POKEMON_EM", span(example));
-
-    example = "POKEMON_E\x00\x00\x00";
-    try std.testing.expectEqualSlices(u8, "POKEMON_E", span(example));
-
-    example = "POKEMON_\x00\x00\x00\x00";
-    try std.testing.expectEqualSlices(u8, "POKEMON_", span(example));
-
-    example = "POKEMON\x00\x00\x00\x00\x00";
-    try std.testing.expectEqualSlices(u8, "POKEMON", span(example));
-
-    example = "POKEMO\x00\x00\x00\x00\x00\x00";
-    try std.testing.expectEqualSlices(u8, "POKEMO", span(example));
-
-    example = "POKEM\x00\x00\x00\x00\x00\x00\x00";
-    try std.testing.expectEqualSlices(u8, "POKEM", span(example));
-
-    example = "POKE\x00\x00\x00\x00\x00\x00\x00\x00";
-    try std.testing.expectEqualSlices(u8, "POKE", span(example));
-
-    example = "POK\x00\x00\x00\x00\x00\x00\x00\x00\x00";
-    try std.testing.expectEqualSlices(u8, "POK", span(example));
-
-    example = "PO\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00";
-    try std.testing.expectEqualSlices(u8, "PO", span(example));
-
-    example = "P\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00";
-    try std.testing.expectEqualSlices(u8, "P", span(example));
-
-    example = "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00";
-    try std.testing.expectEqualSlices(u8, "", span(example));
-}
-
 /// Creates a copy of a title with all Filesystem-invalid characters replaced
 ///
 /// e.g. POKEPIN R/S to POKEPIN R_S