initial commit

Signed-off-by: Xe Iaso <me@christine.website>

README.md

@@ -1,4 +1,4 @@
-# snek
+# tamamo
 
 A game written in Zig for the [WASM-4](https://wasm4.org) fantasy console.
 

build.zig

@@ -1,27 +1,69 @@
 const std = @import("std");
 
-pub fn build(b: *std.build.Builder) void {
+// Returns true if the version includes https://github.com/ziglang/zig/pull/10572/commits.
-    const mode = b.standardReleaseOptions();
+// When this is false, trying to place the stack first will result in data corruption.
+fn version_supports_stack_first(zig_version: std.SemanticVersion) !bool {
+    if (zig_version.order(try std.SemanticVersion.parse("0.10.0")).compare(.gte)) {
+        // Merged here: https://github.com/ziglang/zig/pull/10572
+        return true;
+    }
+    if (zig_version.major == 0 and zig_version.minor == 10) {
+        // Check for 0.10.0-dev.258+. Conservatively check the prefix of the tag
+        // in case zig uses other prefixes that don't respect semver ordering.
+        if (zig_version.pre) |pre| {
+            // Merged here: https://github.com/ziglang/zig/pull/10572
+            return std.mem.startsWith(u8, pre, "dev.") and zig_version.order(try std.SemanticVersion.parse("0.10.0-dev.258")).compare(.gte);
+        }
+    }
+    // Backported here: https://github.com/ziglang/zig/commit/6f49233ac6a6569b909b689f22fc260dc8c19234
+    return zig_version.order(try std.SemanticVersion.parse("0.9.1")).compare(.gte);
+}
 
+test "stack version check" {
+    const expect = std.testing.expect;
+    const parse = std.SemanticVersion.parse;
+    try expect(!try version_supports_stack_first(try parse("0.8.0")));
+
+    try expect(!try version_supports_stack_first(try parse("0.9.0")));
+    try expect(!try version_supports_stack_first(try parse("0.9.1-dev.259")));
+    try expect(try version_supports_stack_first(try parse("0.9.1")));
+
+    // Conservatively don't recognize tags other than 'dev'.
+    try expect(!try version_supports_stack_first(try parse("0.10.0-aev.259")));
+    try expect(!try version_supports_stack_first(try parse("0.10.0-zev.259")));
+
+    try expect(!try version_supports_stack_first(try parse("0.10.0-dev.257")));
+    try expect(try version_supports_stack_first(try parse("0.10.0-dev.258")));
+    try expect(try version_supports_stack_first(try parse("0.10.0-dev.259")));
+    try expect(try version_supports_stack_first(try parse("0.10.0")));
+
+    try expect(try version_supports_stack_first(try parse("0.10.1-dev.100")));
+    try expect(try version_supports_stack_first(try parse("0.10.1-dev.300")));
+    try expect(try version_supports_stack_first(try parse("0.10.1")));
+
+    try expect(try version_supports_stack_first(try parse("1.0.0")));
+}
+
+pub fn build(b: *std.build.Builder) !void {
+    const zig_version = @import("builtin").zig_version;
+    const mode = b.standardReleaseOptions();
     const lib = b.addSharedLibrary("cart", "src/main.zig", .unversioned);
     lib.setBuildMode(mode);
     lib.setTarget(.{ .cpu_arch = .wasm32, .os_tag = .freestanding });
     lib.import_memory = true;
     lib.initial_memory = 65536;
     lib.max_memory = 65536;
+    if (try version_supports_stack_first(zig_version)) {
+        lib.stack_size = 14752;
+    } else {
+        // `--stack-first` option have been reenabled on wasm targets with https://github.com/ziglang/zig/pull/10572
+        std.log.warn("Update to Zig >=0.9.1 (or >=0.10.0-dev.258 for nightly) to detect stack overflows at runtime.", .{});
         lib.global_base = 6560;
         lib.stack_size = 8192;
+    }
+    // Workaround https://github.com/ziglang/zig/issues/2910, preventing
+    // functions from compiler_rt getting incorrectly marked as exported, which
+    // prevents them from being removed even if unused.
     lib.export_symbol_names = &[_][]const u8{ "start", "update" };
     lib.install();
-
-    const lib_artifact = b.addInstallArtifact(lib);
-
-    const run_command = b.addSystemCommand(&.{
-        "w4", "run", "zig-out/lib/cart.wasm",
-        "--no-open",
-    });
-    run_command.step.dependOn(&lib_artifact.step);
-
-    const run_step = b.step("run", "Run the app");
-    run_step.dependOn(&run_command.step);
 }

sprites/TownTiles.tsx

@@ -0,0 +1,4 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<tileset version="1.8" tiledversion="1.8.2" name="TownTiles" tilewidth="8" tileheight="8" tilecount="288" columns="24">
+ <image source="TownTiles.png" width="192" height="96"/>
+</tileset>

src/main.zig

@@ -11,17 +11,15 @@ const smiley = [8]u8{
     0b11000011,
 };
 
-export fn start() void {}
-
 export fn update() void {
-    w4.m.colors._0 = .p1;
+    w4.DRAW_COLORS.* = 2;
     w4.text("Hello from Zig!", 10, 10);
 
-    const gamepad = w4.m.gamepads[0];
+    const gamepad = w4.GAMEPAD1.*;
-    if (gamepad.a) {
+    if (gamepad & w4.BUTTON_1 != 0) {
-        w4.m.colors._0 = .p3;
+        w4.DRAW_COLORS.* = 4;
     }
 
-    w4.blit(&smiley, 76, 76, 8, 8, .{});
+    w4.blit(&smiley, 76, 76, 8, 8, w4.BLIT_1BPP);
     w4.text("Press X to blink", 16, 90);
 }

src/wasm4.zig

@@ -1,25 +1,13 @@
 //
 // WASM-4: https://wasm4.org/docs
 
-const std = @import("std");
-
-fn assert_equal(a: anytype, b: anytype, comptime error_msg: []const u8) void {
-    if (a != b) @compileError(std.fmt.comptimePrint("{} != {}  {s}", .{a, b, error_msg}));
-}
-
-comptime {
-    const builtin = @import("builtin");
-    const native_endian = builtin.target.cpu.arch.endian();
-    assert_equal(native_endian, .Little, "Bit flags need little endian");
-}
-
 // ┌───────────────────────────────────────────────────────────────────────────┐
 // │                                                                           │
 // │ Platform Constants                                                        │
 // │                                                                           │
 // └───────────────────────────────────────────────────────────────────────────┘
 
-pub const SCREEN_SIZE: u32 = 160;
+pub const CANVAS_SIZE: u32 = 160;
 
 // ┌───────────────────────────────────────────────────────────────────────────┐
 // │                                                                           │
@@ -27,99 +15,31 @@ pub const SCREEN_SIZE: u32 = 160;
 // │                                                                           │
 // └───────────────────────────────────────────────────────────────────────────┘
 
-pub const Memory = packed struct {
+pub const PALETTE: *[4]u32 = @intToPtr(*[4]u32, 0x04);
-    _padding: [4]u8,
+pub const DRAW_COLORS: *u16 = @intToPtr(*u16, 0x14);
-    palette: [4]Color,
+pub const GAMEPAD1: *const u8 = @intToPtr(*const u8, 0x16);
-    colors: DrawColors,
+pub const GAMEPAD2: *const u8 = @intToPtr(*const u8, 0x17);
-    gamepads: [4]GamePad,
+pub const GAMEPAD3: *const u8 = @intToPtr(*const u8, 0x18);
-    mouse: Mouse,
+pub const GAMEPAD4: *const u8 = @intToPtr(*const u8, 0x19);
-    system: SystemFlags,
+pub const MOUSE_X: *const i16 = @intToPtr(*const i16, 0x1a);
-    _reserved: [128]u8,
+pub const MOUSE_Y: *const i16 = @intToPtr(*const i16, 0x1c);
-    framebuffer: [6400]u8,
+pub const MOUSE_BUTTONS: *const u8 = @intToPtr(*const u8, 0x1e);
-    userdata: [58976]u8,
+pub const SYSTEM_FLAGS: *u8 = @intToPtr(*u8, 0x1f);
-};
+pub const FRAMEBUFFER: *[6400]u8 = @intToPtr(*[6400]u8, 0xA0);
 
-comptime {
+pub const BUTTON_1: u8 = 1;
-    assert_equal(@bitSizeOf(Memory), 64 * 1024 * 8, "Memory layout wrong");
+pub const BUTTON_2: u8 = 2;
-}
+pub const BUTTON_LEFT: u8 = 16;
+pub const BUTTON_RIGHT: u8 = 32;
+pub const BUTTON_UP: u8 = 64;
+pub const BUTTON_DOWN: u8 = 128;
 
-const dummym: Memory = undefined;
+pub const MOUSE_LEFT: u8 = 1;
+pub const MOUSE_RIGHT: u8 = 2;
+pub const MOUSE_MIDDLE: u8 = 4;
 
-pub const m = struct {
+pub const SYSTEM_PRESERVE_FRAMEBUFFER: u8 = 1;
-    pub const palette     = @intToPtr(*@TypeOf(dummym.palette    ), 0 + @offsetOf(Memory, "palette"    ));
+pub const SYSTEM_HIDE_GAMEPAD_OVERLAY: u8 = 2;
-    pub const colors      = @intToPtr(*@TypeOf(dummym.colors     ), 0 + @offsetOf(Memory, "colors"     ));
-    pub const gamepads    = @intToPtr(*@TypeOf(dummym.gamepads   ), 0 + @offsetOf(Memory, "gamepads"   ));
-    pub const mouse       = @intToPtr(*@TypeOf(dummym.mouse      ), 0 + @offsetOf(Memory, "mouse"      ));
-    pub const system      = @intToPtr(*@TypeOf(dummym.system     ), 0 + @offsetOf(Memory, "system"     ));
-    pub const framebuffer = @intToPtr(*@TypeOf(dummym.framebuffer), 0 + @offsetOf(Memory, "framebuffer"));
-    pub const userdata    = @intToPtr(*@TypeOf(dummym.userdata   ), 0 + @offsetOf(Memory, "userdata"   ));
-};
-
-pub const Color = packed struct {
-    blue  : u8,
-    green : u8,
-    red   : u8,
-    _reserved: u8 = 0,
-};
-
-pub const DrawColors = packed struct {
-    _0: ColorIndex,
-    _1: ColorIndex,
-    _2: ColorIndex,
-    _3: ColorIndex,
-};
-
-pub const ColorIndex = enum(u4) {
-    transparent = 0,
-    /// Use palette[0]
-    p0   = 1,
-    /// Use palette[1]
-    p1   = 2,
-    /// Use palette[2]
-    p2   = 3,
-    /// Use palette[3]
-    p3   = 4,
-};
-
-pub const GamePad = packed struct {
-    a: bool,
-    b: bool,
-    _reserved: u2,
-    left: bool,
-    right: bool,
-    up: bool,
-    down: bool,
-};
-
-pub const Mouse = packed struct {
-    x: i16,
-    y: i16,
-    /// primary button
-    b0: bool,
-    /// secondary button
-    b1: bool,
-    /// third button
-    b2: bool,
-    _reserved: u5,
-};
-
-pub const SystemFlags = packed struct {
-    preserve_framebuffer: bool,
-    hide_gamepad_overlay: bool,
-    _reserved: u6,
-};
-
-// ┌───────────────────────────────────────────────────────────────────────────┐
-// │                                                                           │
-// │ Raw Functions                                                             │
-// │                                                                           │
-// └───────────────────────────────────────────────────────────────────────────┘
-
-const raw_api = struct {
-    extern fn blit(sprite: [*]const u8, x: u32, y: u32, width: u32, height: u32, flags: u32) void;
-    extern fn blitSub(sprite: [*]const u8, x: u32, y: u32, width: u32, height: u32, src_x: u32, src_y: u32, stride: u32, flags: u32) void;
-    extern fn tone(frequency: u32, duration: u32, volume: u32, flags: u32) void;
-};
 
 // ┌───────────────────────────────────────────────────────────────────────────┐
 // │                                                                           │
@@ -127,49 +47,38 @@ const raw_api = struct {
 // │                                                                           │
 // └───────────────────────────────────────────────────────────────────────────┘
 
-pub const BlitFlags = packed struct {
-    /// one or two bits per pixel
-    two_bits:  bool = false,
-    flip_x: bool = false,
-    flip_y: bool = false,
-    rotate: bool = false,
-    _reserved: u28 = 0,
-};
-
 /// Copies pixels to the framebuffer.
-pub fn blit(sprite: []const u8, x: u32, y: u32, width: u32, height: u32, flags: BlitFlags) void {
+pub extern fn blit(sprite: [*]const u8, x: i32, y: i32, width: i32, height: i32, flags: u32) void;
-    
-    raw_api.blit(sprite.ptr, x, y, width, height, @bitCast(u32, flags));
-}
 
 /// Copies a subregion within a larger sprite atlas to the framebuffer.
-/// srcX: Source X position of the sprite region.
+pub extern fn blitSub(sprite: [*]const u8, x: i32, y: i32, width: i32, height: i32, src_x: u32, src_y: u32, stride: i32, flags: u32) void;
-/// srcY: Source Y position of the sprite region.
+
-/// stride: Total width of the overall sprite atlas. This is typically larger than width.
+pub const BLIT_2BPP: u32 = 1;
-pub fn blitSub(sprite: []const u8, x: u32, y: u32, width: u32, height: u32, src_x: u32, src_y: u32, stride: u32, flags: BlitFlags) void {
+pub const BLIT_1BPP: u32 = 0;
-    raw_api.blitSub(sprite.ptr, x, y, width, height, src_x, src_y, stride, @bitCast(u32, flags));
+pub const BLIT_FLIP_X: u32 = 2;
-}
+pub const BLIT_FLIP_Y: u32 = 4;
+pub const BLIT_ROTATE: u32 = 8;
 
 /// Draws a line between two points.
-pub extern fn line(x1: u32, y1: u32, x2: u32, y2: u32) void;
+pub extern fn line(x1: i32, y1: i32, x2: i32, y2: i32) void;
 
 /// Draws an oval (or circle).
-pub extern fn oval(x: u32, y: u32, width: u32, height: u32) void;
+pub extern fn oval(x: i32, y: i32, width: i32, height: i32) void;
 
 /// Draws a rectangle.
-pub extern fn rect(x: u32, y: u32, width: u32, height: u32) void;
+pub extern fn rect(x: i32, y: i32, width: u32, height: u32) void;
 
 /// Draws text using the built-in system font.
-pub fn text(str: []const u8, x: u32, y: u32) void {
+pub fn text(str: []const u8, x: i32, y: i32) void {
     textUtf8(str.ptr, str.len, x, y);
 }
-extern fn textUtf8(strPtr: [*]const u8, strLen: usize, x: u32, y: u32) void;
+extern fn textUtf8(strPtr: [*]const u8, strLen: usize, x: i32, y: i32) void;
 
 /// Draws a vertical line
-pub extern fn vline(x: u32, y: u32, len: u32) void;
+pub extern fn vline(x: i32, y: i32, len: u32) void;
 
 /// Draws a horizontal line
-pub extern fn hline(x: u32, y: u32, len: u32) void;
+pub extern fn hline(x: i32, y: i32, len: u32) void;
 
 // ┌───────────────────────────────────────────────────────────────────────────┐
 // │                                                                           │
@@ -178,81 +87,16 @@ pub extern fn hline(x: u32, y: u32, len: u32) void;
 // └───────────────────────────────────────────────────────────────────────────┘
 
 /// Plays a sound tone.
-/// frequency: Wave frequency in hertz.
+pub extern fn tone(frequency: u32, duration: u32, volume: u32, flags: u32) void;
-/// duration: Duration of the tone in frames (1/60th of a second), up to 255 frames.
-/// volume: Volume of the sustain and attack durations, between 0 and 100.
-pub fn tone(frequency: Tone.Frequency, duration: Tone.Duration, volume: Tone.Volume, flags: Tone.Flags) void {
-    std.debug.assert(volume.is_valid());
-    tone(@bitCast(u32, frequency), @bitCast(u32, duration), @bitCast(u32, volume), @bitCast(u32, flags));
-}
 
-pub const Tone = struct {
+pub const TONE_PULSE1: u32 = 0;
-    /// Wave frequency in hertz.
+pub const TONE_PULSE2: u32 = 1;
-    pub const Frequency = packed struct {
+pub const TONE_TRIANGLE: u32 = 2;
-        start: u16,
+pub const TONE_NOISE: u32 = 3;
-        end: u16 = 0,
+pub const TONE_MODE1: u32 = 0;
-    };
+pub const TONE_MODE2: u32 = 4;
-    
+pub const TONE_MODE3: u32 = 8;
-    /// Duration of ADSR of note (unit: frames)
+pub const TONE_MODE4: u32 = 12;
-    ///
-    ///          ^
-    ///         / \ decay
-    /// attack /   \ 
-    ///       /     \--------
-    ///      /       sustain \ release
-    ///     /                 \
-    pub const Duration = packed struct {
-        sustain : u8 = 0,
-        release : u8 = 0,
-        decay   : u8 = 0,
-        attack  : u8 = 0,
-    };
-    
-    /// Volume of note (0 to 100)
-    ///
-    ///          ^  <-- attack volume
-    ///         / \
-    ///        /   \ 
-    ///       /     \--------  <-- sustain valume
-    ///      /               \
-    ///     /                 \
-    pub const Volume = packed struct {
-        sustain : u8,
-        attack  : u8 = 100,
-
-        pub fn is_valid(volume: @This()) bool {
-            return (0 <= volume.sustain) and (volume.sustain <= 100)
-               and (0 <= volume.attack ) and (volume.attack  <= 100);
-        }
-    };
-
-    pub const Flags = packed struct {
-        channel: Channel,
-        pulse_duty: DutyCycle = 2,
-        pan: Pan = .both,
-    };
-
-    pub const Channel = enum(u2) {
-        pulse0 = 0,
-        pulse1 = 1,
-        triangle = 2,
-        noise = 3,
-    };
-
-    pub const DutyCycle = enum(u2) {
-        @"1/8" = 0,
-        @"1/4" = 1,
-        @"1/2" = 2,
-    };
-
-    /// Which stereo channel(s) to play audio in
-    pub const Pan = enum(u2) {
-        /// play audio in both stereo channels
-        both  = 0,
-        left  = 1,
-        right = 2,
-    };
-};
 
 // ┌───────────────────────────────────────────────────────────────────────────┐
 // │                                                                           │
@@ -277,3 +121,13 @@ pub fn trace(x: []const u8) void {
     traceUtf8(x.ptr, x.len);
 }
 extern fn traceUtf8(strPtr: [*]const u8, strLen: usize) void;
+
+/// Use with caution, as there's no compile-time type checking.
+///
+/// * %c, %d, and %x expect 32-bit integers.
+/// * %f expects 64-bit floats.
+/// * %s expects a *zero-terminated* string pointer.
+///
+/// See https://github.com/aduros/wasm4/issues/244 for discussion and type-safe
+/// alternatives.
+pub extern fn tracef(x: [*:0]const u8, ...) void;