Initial template

.gitignore

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+zig-cache/
+zig-out/

README.md

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+# snek
+
+A game written in Zig for the [WASM-4](https://wasm4.org) fantasy console.
+
+## Building
+
+Build the cart by running:
+
+```shell
+zig build -Drelease-small=true
+```
+
+Then run it with:
+
+```shell
+w4 run zig-out/lib/cart.wasm
+```
+
+For more info about setting up WASM-4, see the [quickstart guide](https://wasm4.org/docs/getting-started/setup?code-lang=zig#quickstart).
+
+## Links
+
+- [Documentation](https://wasm4.org/docs): Learn more about WASM-4.
+- [Snake Tutorial](https://wasm4.org/docs/tutorials/snake/goal): Learn how to build a complete game
+  with a step-by-step tutorial.
+- [GitHub](https://github.com/aduros/wasm4): Submit an issue or PR. Contributions are welcome!

build.zig

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+const std = @import("std");
+
+pub fn build(b: *std.build.Builder) !void {
+    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;
+    lib.stack_size = 14752;
+
+    // Export WASM-4 symbols
+    lib.export_symbol_names = &[_][]const u8{ "start", "update" };
+
+    lib.install();
+}

src/main.zig

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+const w4 = @import("wasm4.zig");
+
+const smiley = [8]u8{
+    0b11000011,
+    0b10000001,
+    0b00100100,
+    0b00100100,
+    0b00000000,
+    0b00100100,
+    0b10011001,
+    0b11000011,
+};
+
+export fn update() void {
+    w4.DRAW_COLORS.* = 2;
+    w4.text("Hello from Zig!", 10, 10);
+
+    const gamepad = w4.GAMEPAD1.*;
+    if (gamepad & w4.BUTTON_1 != 0) {
+        w4.DRAW_COLORS.* = 4;
+    }
+
+    w4.blit(&smiley, 76, 76, 8, 8, w4.BLIT_1BPP);
+    w4.text("Press X to blink", 16, 90);
+}

src/wasm4.zig

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+//
+// WASM-4: https://wasm4.org/docs
+
+// ┌───────────────────────────────────────────────────────────────────────────┐
+// │                                                                           │
+// │ Platform Constants                                                        │
+// │                                                                           │
+// └───────────────────────────────────────────────────────────────────────────┘
+
+pub const SCREEN_SIZE: u32 = 160;
+
+// ┌───────────────────────────────────────────────────────────────────────────┐
+// │                                                                           │
+// │ Memory Addresses                                                          │
+// │                                                                           │
+// └───────────────────────────────────────────────────────────────────────────┘
+
+pub const PALETTE: *[4]u32 = @intToPtr(*[4]u32, 0x04);
+pub const DRAW_COLORS: *u16 = @intToPtr(*u16, 0x14);
+pub const GAMEPAD1: *const u8 = @intToPtr(*const u8, 0x16);
+pub const GAMEPAD2: *const u8 = @intToPtr(*const u8, 0x17);
+pub const GAMEPAD3: *const u8 = @intToPtr(*const u8, 0x18);
+pub const GAMEPAD4: *const u8 = @intToPtr(*const u8, 0x19);
+pub const MOUSE_X: *const i16 = @intToPtr(*const i16, 0x1a);
+pub const MOUSE_Y: *const i16 = @intToPtr(*const i16, 0x1c);
+pub const MOUSE_BUTTONS: *const u8 = @intToPtr(*const u8, 0x1e);
+pub const SYSTEM_FLAGS: *u8 = @intToPtr(*u8, 0x1f);
+pub const FRAMEBUFFER: *[6400]u8 = @intToPtr(*[6400]u8, 0xA0);
+
+pub const BUTTON_1: u8 = 1;
+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;
+
+pub const MOUSE_LEFT: u8 = 1;
+pub const MOUSE_RIGHT: u8 = 2;
+pub const MOUSE_MIDDLE: u8 = 4;
+
+pub const SYSTEM_PRESERVE_FRAMEBUFFER: u8 = 1;
+pub const SYSTEM_HIDE_GAMEPAD_OVERLAY: u8 = 2;
+
+// ┌───────────────────────────────────────────────────────────────────────────┐
+// │                                                                           │
+// │ Drawing Functions                                                         │
+// │                                                                           │
+// └───────────────────────────────────────────────────────────────────────────┘
+
+/// Copies pixels to the framebuffer.
+pub extern fn blit(sprite: [*]const u8, x: i32, y: i32, width: i32, height: i32, flags: u32) void;
+
+/// Copies a subregion within a larger sprite atlas to the framebuffer.
+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;
+
+pub const BLIT_2BPP: u32 = 1;
+pub const BLIT_1BPP: u32 = 0;
+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: i32, y1: i32, x2: i32, y2: i32) void;
+
+/// Draws an oval (or circle).
+pub extern fn oval(x: i32, y: i32, width: i32, height: i32) void;
+
+/// Draws a rectangle.
+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: i32, y: i32) void {
+    textUtf8(str.ptr, str.len, x, y);
+}
+extern fn textUtf8(strPtr: [*]const u8, strLen: usize, x: i32, y: i32) void;
+
+/// Draws a vertical line
+pub extern fn vline(x: i32, y: i32, len: u32) void;
+
+/// Draws a horizontal line
+pub extern fn hline(x: i32, y: i32, len: u32) void;
+
+// ┌───────────────────────────────────────────────────────────────────────────┐
+// │                                                                           │
+// │ Sound Functions                                                           │
+// │                                                                           │
+// └───────────────────────────────────────────────────────────────────────────┘
+
+/// Plays a sound tone.
+pub extern fn tone(frequency: u32, duration: u32, volume: u32, flags: u32) void;
+
+pub const TONE_PULSE1: u32 = 0;
+pub const TONE_PULSE2: u32 = 1;
+pub const TONE_TRIANGLE: u32 = 2;
+pub const TONE_NOISE: u32 = 3;
+pub const TONE_MODE1: u32 = 0;
+pub const TONE_MODE2: u32 = 4;
+pub const TONE_MODE3: u32 = 8;
+pub const TONE_MODE4: u32 = 12;
+pub const TONE_PAN_LEFT: u32 = 16;
+pub const TONE_PAN_RIGHT: u32 = 32;
+
+// ┌───────────────────────────────────────────────────────────────────────────┐
+// │                                                                           │
+// │ Storage Functions                                                         │
+// │                                                                           │
+// └───────────────────────────────────────────────────────────────────────────┘
+
+/// Reads up to `size` bytes from persistent storage into the pointer `dest`.
+pub extern fn diskr(dest: [*]u8, size: u32) u32;
+
+/// Writes up to `size` bytes from the pointer `src` into persistent storage.
+pub extern fn diskw(src: [*]const u8, size: u32) u32;
+
+// ┌───────────────────────────────────────────────────────────────────────────┐
+// │                                                                           │
+// │ Other Functions                                                           │
+// │                                                                           │
+// └───────────────────────────────────────────────────────────────────────────┘
+
+/// Prints a message to the debug console.
+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;