1.2.zig

const std = @import("std");
const glfw = @import("mach-glfw");
const gl = @import("zgl");

const log = std.log.scoped(.Engine);

const SCR_WIDTH = 800;
const SCR_HEIGHT = 600;

fn glGetProcAddress(p: glfw.GLProc, proc: [:0]const u8) ?gl.binding.FunctionPointer {
    _ = p;
    return glfw.getProcAddress(proc);
}

/// Default GLFW error handling callback
fn errorCallback(error_code: glfw.ErrorCode, description: [:0]const u8) void {
    std.log.err("glfw: {}: {s}\n", .{ error_code, description });
}

pub fn main() !void {
    // glfw.setErrorCallback(errorCallback);
    if (!glfw.init(.{})) {
        std.log.err("failed to initialize GLFW: {?s}", .{glfw.getErrorString()});
        std.process.exit(1);
    }
    defer glfw.terminate();

    // Create our window
    const window = glfw.Window.create(640, 480, "Learn opengl", null, null, .{
        .opengl_profile = .opengl_core_profile,
        .context_version_major = 4,
        .context_version_minor = 4,
    }) orelse {
        std.log.err("failed to create GLFW window: {?s}", .{glfw.getErrorString()});
        std.process.exit(1);
    };
    defer window.destroy();
    glfw.makeContextCurrent(window);

    const proc: glfw.GLProc = undefined;
    try gl.loadExtensions(proc, glGetProcAddress);

    // render loop
    // -----------
    while (!window.shouldClose()) {
        processInput(window);

        // render
        // ------
        gl.clearColor(0.2, 0.3, 0.3, 1.0);
        gl.clear(.{.color = true});

        window.swapBuffers();
        glfw.pollEvents();
    }
}

// process all input: query GLFW whether relevant keys are pressed/released this frame and react accordingly
// ---------------------------------------------------------------------------------------------------------
fn processInput(window: glfw.Window) void {
    if (window.getKey(glfw.Key.escape) == glfw.Action.press) {
        window.setShouldClose(true);
    }
}