hypatia/main.zig

const std = @import("std");

const zglfw = @import("zglfw");
const zgpu = @import("zgpu");
const wgpu = zgpu.wgpu;
const zgui = @import("zgui");

pub fn main() !void {
    try zglfw.init();
    defer zglfw.terminate();

    zglfw.windowHintTyped(.client_api, .no_api);

    const window = try zglfw.Window.create(800, 500, "HELLOWORLD", null);
    defer window.destroy();
    window.setSizeLimits(400, 400, -1, -1);

    var gpa_state = std.heap.GeneralPurposeAllocator(.{}){};
    defer _ = gpa_state.deinit();
    const gpa = gpa_state.allocator();

    const gctx = try zgpu.GraphicsContext.create(
        gpa,
        .{
            .window = window,
            .fn_getTime = @ptrCast(&zglfw.getTime),
            .fn_getFramebufferSize = @ptrCast(&zglfw.Window.getFramebufferSize),
            .fn_getWin32Window = @ptrCast(&zglfw.getWin32Window),
            .fn_getX11Display = @ptrCast(&zglfw.getX11Display),
            .fn_getX11Window = @ptrCast(&zglfw.getX11Window),
            .fn_getWaylandDisplay = @ptrCast(&zglfw.getWaylandDisplay),
            .fn_getWaylandSurface = @ptrCast(&zglfw.getWaylandWindow),
            .fn_getCocoaWindow = @ptrCast(&zglfw.getCocoaWindow),
        },
        .{},
    );
    defer gctx.destroy(gpa);

    zgui.init(gpa);
    defer zgui.deinit();

    zgui.backend.init(
        window,
        gctx.device,
        @intFromEnum(zgpu.GraphicsContext.swapchain_format),
        @intFromEnum(wgpu.TextureFormat.undef),
    );
    defer zgui.backend.deinit();

    var prev_scale: f32 = 1.0;
    while (!window.shouldClose() and window.getKey(.escape) != .press) {
        zglfw.pollEvents();

        const scale_factor = scale_factor: {
            const scale = window.getContentScale();
            break :scale_factor @max(scale[0], scale[1]);
        };
        std.debug.print("{}", .{scale_factor / prev_scale});
        zgui.getStyle().scaleAllSizes(scale_factor / prev_scale);
        prev_scale = scale_factor;

        zgui.backend.newFrame(
            gctx.swapchain_descriptor.width,
            gctx.swapchain_descriptor.height,
        );

        // Set the starting window position and size to custom values
        zgui.setNextWindowPos(.{ .x = 20.0, .y = 20.0, .cond = .first_use_ever });
        zgui.setNextWindowSize(.{ .w = -1.0, .h = -1.0, .cond = .first_use_ever });

        if (zgui.begin("My window", .{})) {
            if (zgui.button("Press me!", .{ .w = 200.0 })) {
                std.debug.print("Button pressed\n", .{});
            }
        }
        zgui.end();

        const swapchain_texv = gctx.swapchain.getCurrentTextureView();
        defer swapchain_texv.release();

        const commands = commands: {
            const encoder = gctx.device.createCommandEncoder(null);
            defer encoder.release();

            // GUI pass
            {
                const pass = zgpu.beginRenderPassSimple(encoder, .load, swapchain_texv, null, null, null);
                defer zgpu.endReleasePass(pass);
                zgui.backend.draw(pass);
            }

            break :commands encoder.finish(null);
        };
        defer commands.release();

        gctx.submit(&.{commands});
        _ = gctx.present();
    }
}