initial version

.gitignore

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+/zig-cache/

README.md

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+# SDL2 Zig Demo
+
+Here's a basic window with SDL2 in Zig.
+
+![screenshot](screenshot.png)
+
+## How to build and run it
+
+```
+zig build run
+```

build.zig

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+const Builder = @import("std").build.Builder;
+
+pub fn build(b: &Builder) {
+    const mode = b.standardReleaseOptions();
+    const exe = b.addExecutable("sdl-zig-demo", "src/main.zig");
+    exe.setBuildMode(mode);
+    exe.linkSystemLibrary("SDL2");
+    exe.linkSystemLibrary("c");
+
+    b.default_step.dependOn(&exe.step);
+    b.installArtifact(exe);
+
+
+    const run = b.step("run", "Run the demo");
+    const run_cmd = b.addCommand(".", b.env_map,
+        [][]const u8{exe.getOutputPath(), });
+    run.dependOn(&run_cmd.step);
+    run_cmd.step.dependOn(&exe.step);
+}

src/main.zig

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+const c = @cImport({
+    @cInclude("SDL2/SDL.h");
+});
+const assert = @import("std").debug.assert;
+
+
+// See https://github.com/zig-lang/zig/issues/565
+// SDL_video.h:#define SDL_WINDOWPOS_UNDEFINED         SDL_WINDOWPOS_UNDEFINED_DISPLAY(0)
+// SDL_video.h:#define SDL_WINDOWPOS_UNDEFINED_DISPLAY(X)  (SDL_WINDOWPOS_UNDEFINED_MASK|(X))
+// SDL_video.h:#define SDL_WINDOWPOS_UNDEFINED_MASK    0x1FFF0000u
+const SDL_WINDOWPOS_UNDEFINED = @bitCast(c_int, c.SDL_WINDOWPOS_UNDEFINED_MASK);
+
+// Zig does not support extern unions yet.
+// See https://github.com/zig-lang/zig/issues/144
+const SDL_Event = extern struct {
+    _type: c.Uint32,
+    _union: [56]u8,
+};
+extern fn SDL_PollEvent(event: &SDL_Event) -> c_int;
+
+// SDL_RWclose is fundamentally unrepresentable in Zig, because `ctx` is
+// evaluated twice. One could make the case that this is a bug in SDL,
+// especially since the docs list a real function prototype that would not
+// have this double-evaluation of the parameter.
+// If SDL would instead of a macro use a static inline function,
+// it would resolve the SDL bug as well as make the function visible to Zig
+// and to debuggers.
+// SDL_rwops.h:#define SDL_RWclose(ctx)        (ctx)->close(ctx)
+inline fn SDL_RWclose(ctx: &c.SDL_RWops) -> c_int {
+    const aligned_ctx = @alignCast(@alignOf(my_SDL_RWops), ctx);
+    const casted_ctx = @ptrCast(&my_SDL_RWops, aligned_ctx);
+    return casted_ctx.close(casted_ctx);
+}
+// Zig does not support extern unions yet.
+// See https://github.com/zig-lang/zig/issues/144
+const my_SDL_RWops = extern struct {
+    size: extern fn(),
+    seek: extern fn(),
+    read: extern fn(),
+    write: extern fn(),
+    close: extern fn(context: &my_SDL_RWops)->c_int,
+};
+
+error SDLInitializationFailed;
+
+pub fn main() -> %void {
+    if (c.SDL_Init(c.SDL_INIT_VIDEO) != 0) {
+        c.SDL_Log(c"Unable to initialize SDL: %s", c.SDL_GetError());
+        return error.SDLInitializationFailed;
+    }
+    defer c.SDL_Quit();
+
+    const screen = c.SDL_CreateWindow(c"My Game Window",
+            SDL_WINDOWPOS_UNDEFINED,
+            SDL_WINDOWPOS_UNDEFINED,
+            300, 73,
+            c.SDL_WINDOW_OPENGL) ??
+    {
+        c.SDL_Log(c"Unable to create window: %s", c.SDL_GetError());
+        return error.SDLInitializationFailed;
+    };
+    defer c.SDL_DestroyWindow(screen);
+
+    const renderer = c.SDL_CreateRenderer(screen, -1, 0) ?? {
+        c.SDL_Log(c"Unable to create renderer: %s", c.SDL_GetError());
+        return error.SDLInitializationFailed;
+    };
+    defer c.SDL_DestroyRenderer(renderer);
+
+    const zig_bmp = @embedFile("zig.bmp");
+    const rw = c.SDL_RWFromConstMem(@ptrCast(&c_void, &zig_bmp[0]), c_int(zig_bmp.len)) ?? {
+        c.SDL_Log(c"Unable to get RWFromConstMem: %s", c.SDL_GetError());
+        return error.SDLInitializationFailed;
+    };
+    defer assert(SDL_RWclose(rw) == 0);
+
+    const zig_surface = c.SDL_LoadBMP_RW(rw, 1) ?? {
+        c.SDL_Log(c"Unable to load bmp: %s", c.SDL_GetError());
+        return error.SDLInitializationFailed;
+    };
+    defer c.SDL_FreeSurface(zig_surface);
+
+    const zig_texture = c.SDL_CreateTextureFromSurface(renderer, zig_surface) ?? {
+        c.SDL_Log(c"Unable to create texture from surface: %s", c.SDL_GetError());
+        return error.SDLInitializationFailed;
+    };
+    defer c.SDL_DestroyTexture(zig_texture);
+
+    var quit = false;
+    while (!quit) {
+        var event: SDL_Event = undefined;
+        while (SDL_PollEvent(&event) != 0) {
+            switch (event._type) {
+                c.SDL_QUIT => {
+                    quit = true;
+                },
+                else => {},
+            }
+        }
+
+        _ = c.SDL_RenderClear(renderer);
+        _ = c.SDL_RenderCopy(renderer, zig_texture, null, null);
+        c.SDL_RenderPresent(renderer);
+
+        c.SDL_Delay(17);
+    }
+}