188 lines
8.3 KiB
Zig
188 lines
8.3 KiB
Zig
//
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// WASM-4: https://wasm4.org/docs
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const std = @import("std");
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fn assert_equal(a: anytype, b: anytype, comptime error_msg: []const u8) void {
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if (a != b) @compileError(std.fmt.comptimePrint("{} != {} {s}", .{a, b, error_msg}));
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}
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comptime {
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const builtin = @import("builtin");
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const native_endian = builtin.target.cpu.arch.endian();
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assert_equal(native_endian, .Little, "Bit flags need little endian");
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}
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// ┌───────────────────────────────────────────────────────────────────────────┐
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// │ │
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// │ Platform Constants │
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// │ │
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// └───────────────────────────────────────────────────────────────────────────┘
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pub const SCREEN_SIZE: u32 = 160;
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// ┌───────────────────────────────────────────────────────────────────────────┐
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// │ │
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// │ Memory Addresses │
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// │ │
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// └───────────────────────────────────────────────────────────────────────────┘
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pub const Memory = packed struct {
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_padding: [4]u8,
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palette: [4]Color,
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colors: DrawColors,
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gamepads: [4]GamePad,
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mouse: Mouse,
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system: SystemFlags,
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_reserved: [128]u8,
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framebuffer: [6400]u8,
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userdata: [58976]u8,
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};
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comptime {
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assert_equal(@bitSizeOf(Memory), 64 * 1024 * 8, "Memory layout wrong");
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}
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pub const m = @intToPtr(*allowzero Memory, 0);
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pub const Color = packed struct {
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blue : u8,
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green : u8,
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red : u8,
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_reserved: u8 = 0,
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};
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pub const DrawColors = packed struct {
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_0: ColorIndex,
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_1: ColorIndex,
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_2: ColorIndex,
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_3: ColorIndex,
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};
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pub const ColorIndex = enum(u4) {
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transparent = 0,
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_0 = 1,
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_1 = 2,
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_2 = 3,
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_3 = 4,
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};
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pub const GamePad = packed struct {
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x: bool,
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z: bool,
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_reserved: u2,
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left: bool,
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right: bool,
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up: bool,
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down: bool,
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};
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pub const Mouse = packed struct {
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x: i16,
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y: i16,
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_0: bool, // primary button
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_1: bool, // secondary button
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_2: bool, // third button
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_reserved: u5,
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};
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pub const SystemFlags = packed struct {
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preserve_framebuffer: bool,
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hide_gamepad_overlay: bool,
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_reserved: u6,
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};
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// ┌───────────────────────────────────────────────────────────────────────────┐
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// │ │
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// │ Drawing Functions │
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// │ │
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// └───────────────────────────────────────────────────────────────────────────┘
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pub const BlitFlags = packed struct {
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_2bpp: bool = false,
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flip_x: bool = false,
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flip_y: bool = false,
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rotate: bool = false,
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_reserved: u28 = 0,
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};
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/// Copies pixels to the framebuffer.
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pub fn blit(sprite: [*]const u8, x: u32, y: u32, width: u32, height: u32, flags: BlitFlags) void {
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raw_api.blit(sprite, x, y, width, height, @bitCast(u32, flags));
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}
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/// Copies a subregion within a larger sprite atlas to the framebuffer.
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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 {
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raw_api.blitSub(sprite, x, y, width, height, src_x, src_y, stride, @bitCast(u32, flags));
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}
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const raw_api = struct {
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extern fn blit(sprite: [*]const u8, x: u32, y: u32, width: u32, height: u32, flags: u32) void;
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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;
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};
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/// Draws a line between two points.
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pub extern fn line(x1: u32, y1: u32, x2: u32, y2: u32) void;
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/// Draws an oval (or circle).
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pub extern fn oval(x: u32, y: u32, width: u32, height: u32) void;
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/// Draws a rectangle.
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pub extern fn rect(x: u32, y: u32, width: u32, height: u32) void;
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/// Draws text using the built-in system font.
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pub fn text(str: []const u8, x: u32, y: u32) void {
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textUtf8(str.ptr, str.len, x, y);
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}
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extern fn textUtf8(strPtr: [*]const u8, strLen: usize, x: u32, y: u32) void;
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/// Draws a vertical line
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pub extern fn vline(x: u32, y: u32, len: u32) void;
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/// Draws a horizontal line
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pub extern fn hline(x: u32, y: u32, len: u32) void;
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// ┌───────────────────────────────────────────────────────────────────────────┐
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// │ │
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// │ Sound Functions │
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// │ │
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// └───────────────────────────────────────────────────────────────────────────┘
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/// Plays a sound tone.
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pub extern fn tone(frequency: u32, duration: u32, volume: u32, flags: u32) void;
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pub const TONE_PULSE1: u32 = 0;
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pub const TONE_PULSE2: u32 = 1;
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pub const TONE_TRIANGLE: u32 = 2;
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pub const TONE_NOISE: u32 = 3;
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pub const TONE_MODE1: u32 = 0;
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pub const TONE_MODE2: u32 = 4;
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pub const TONE_MODE3: u32 = 8;
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pub const TONE_MODE4: u32 = 12;
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pub const TONE_PAN_LEFT: u32 = 16;
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pub const TONE_PAN_RIGHT: u32 = 32;
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// ┌───────────────────────────────────────────────────────────────────────────┐
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// │ │
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// │ Storage Functions │
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// │ │
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// └───────────────────────────────────────────────────────────────────────────┘
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/// Reads up to `size` bytes from persistent storage into the pointer `dest`.
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pub extern fn diskr(dest: [*]u8, size: u32) u32;
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/// Writes up to `size` bytes from the pointer `src` into persistent storage.
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pub extern fn diskw(src: [*]const u8, size: u32) u32;
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// ┌───────────────────────────────────────────────────────────────────────────┐
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// │ │
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// │ Other Functions │
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// │ │
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// └───────────────────────────────────────────────────────────────────────────┘
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/// Prints a message to the debug console.
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pub fn trace(x: []const u8) void {
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traceUtf8(x.ptr, x.len);
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}
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extern fn traceUtf8(strPtr: [*]const u8, strLen: usize) void;
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