Basic system and window creation.

game.go

@@ -0,0 +1,89 @@
+package goga
+
+import (
+	"github.com/go-gl/glfw/v3.1/glfw"
+	"math"
+	"time"
+)
+
+const (
+	default_width         = uint32(600)
+	default_height        = uint32(400)
+	default_title         = "Game"
+	default_exit_on_close = true
+)
+
+// Run options allow to set some parameters on startup.
+type RunOptions struct {
+	Title       string
+	Width       uint32
+	Height      uint32
+	ExitOnClose bool
+}
+
+// Main game object.
+type Game interface {
+}
+
+var (
+	running = true
+)
+
+// Creates a new window with given options and starts the game.
+// The game struct must implement the Game interface.
+// If options is nil, the default options will be used.
+// This function will panic on error.
+func Run(game Game, options *RunOptions) {
+	// init glfw
+	if err := glfw.Init(); err != nil {
+		panic("Error initializing GLFW: " + err.Error())
+	}
+
+	defer glfw.Terminate()
+
+	// create window
+	width := default_width
+	height := default_height
+	title := default_title
+	exitOnClose := default_exit_on_close
+
+	if options != nil {
+		width = options.Width
+		height = options.Height
+		title = options.Title
+		exitOnClose = options.ExitOnClose
+	}
+
+	wnd, err := glfw.CreateWindow(int(width), int(height), title, nil, nil)
+
+	if err != nil {
+		panic("Error creating GLFW window: " + err.Error())
+	}
+
+	// start and loop
+	wnd.MakeContextCurrent()
+	delta := time.Duration(0)
+	var deltaSec float64
+
+	for running {
+		if exitOnClose && wnd.ShouldClose() {
+			return
+		}
+
+		start := time.Now()
+
+		if !math.IsInf(deltaSec, 0) && !math.IsInf(deltaSec, -1) {
+			updateSystems(deltaSec)
+		}
+
+		delta = time.Since(start)
+		deltaSec = delta.Seconds()
+		wnd.SwapBuffers()
+		glfw.PollEvents()
+	}
+}
+
+// Stops the game and closes the window.
+func Stop() {
+	running = false
+}