main: backport gl02 goodies

cmd/main.cfg.json

@@ -0,0 +1,7 @@
+{
+	"WindowWidth":  1600,
+	"WindowHeight": 900,
+
+	"FramerateLimit": 60
+}
+

cmd/main.go

@@ -13,34 +13,48 @@ import (
 	"github.com/go-gl/glfw/v3.3/glfw"
 )
 
-const (
-	//windowWidth  = 852
-	//windowHeight = 480
-	windowWidth  = 1600
-	windowHeight = 900
+var (
+	frameTick *time.Ticker
 )
 
+
 func init() {
 	runtime.LockOSThread()
 }
+
 func main() {
 
+	err := gio.LoadConfig()
+	if err != nil {
+		panic(err)
+	}
+
 	if err := glfw.Init(); err != nil {
 		panic(err)
 	}
 	defer glfw.Terminate()
 
+	// framerate limit ticker
+	if gio.MainConfig.FramerateLimit > 0 {
+		frameTick = time.NewTicker(time.Second / time.Duration(gio.MainConfig.FramerateLimit))
+	}
+
 	glfw.WindowHint(glfw.Resizable, 1)
 	glfw.WindowHint(glfw.ContextVersionMajor, 3)
 	glfw.WindowHint(glfw.ContextVersionMinor, 3)
 	glfw.WindowHint(glfw.OpenGLProfile, glfw.OpenGLCoreProfile)
 	glfw.WindowHint(glfw.OpenGLForwardCompatible, 1)
-	win, err := glfw.CreateWindow(windowWidth, windowHeight, "Gl01", nil, nil)
+	win, err := glfw.CreateWindow(gio.MainConfig.WindowWidth, gio.MainConfig.WindowHeight, "Gl01", nil, nil)
 	if err != nil {
 		panic(err)
 	}
 	win.MakeContextCurrent()
-	glfw.SwapInterval(1)
+	// vsync
+	if gio.MainConfig.FramerateLimit == 0 {
+		glfw.SwapInterval(1)
+	} else {
+		glfw.SwapInterval(0)
+	}
 
 	err = gl.Init()
 	if err != nil {
@@ -83,5 +97,9 @@ func main() {
 		} else {
 			fpsCounter++
 		}
+
+		if gio.MainConfig.FramerateLimit > 0 {
+			<-frameTick.C
+		}
 	}
 }