Restructure following https://github.com/fogleman/nes ideas

ui/run.go

@@ -0,0 +1,75 @@
+package ui
+
+import (
+	"fmt"
+	"log"
+	"runtime"
+
+	"github.com/veandco/go-sdl2/sdl"
+	"github.com/veandco/go-sdl2/ttf"
+)
+
+var renderer *sdl.Renderer
+var font *ttf.Font
+
+func init() {
+	runtime.LockOSThread()
+}
+
+func Run(romPath string) {
+	if err := sdl.Init(sdl.INIT_EVERYTHING); err != nil {
+		log.Fatal(err)
+	}
+	defer sdl.Quit()
+
+	if err := ttf.Init(); err != nil {
+		log.Fatal((err))
+	}
+	defer ttf.Quit()
+
+	window, err := sdl.CreateWindow(
+		"GB Player",
+		sdl.WINDOWPOS_UNDEFINED,
+		sdl.WINDOWPOS_UNDEFINED,
+		800, 600,
+		sdl.WINDOW_SHOWN)
+	if err != nil {
+		panic(err)
+	}
+	defer window.Destroy()
+
+	renderer, err = sdl.CreateRenderer(window, -1, 0)
+	if err != nil {
+		panic(err)
+	}
+	defer renderer.Destroy()
+	renderer.RenderSetVSync(true)
+
+	font, err = ttf.OpenFont("SourceCodePro.ttf", 18)
+	if err != nil {
+		log.Fatal(err)
+	}
+	defer font.Close()
+	font.SetStyle(ttf.STYLE_BOLD)
+
+	controller := NewController(renderer)
+	controller.Start(romPath)
+}
+
+func drawDebugWindow(fps float64) {
+	// FPS
+	textSurface, err := font.RenderUTF8Blended(fmt.Sprintf("FPS: %.2f", fps), sdl.Color{R: 0, G: 0, B: 0, A: 255})
+	if err != nil {
+		log.Fatal(err)
+	}
+	defer textSurface.Free()
+
+	textTexture, err := renderer.CreateTextureFromSurface(textSurface)
+	if err != nil {
+		log.Fatal(err)
+	}
+	defer textTexture.Destroy()
+
+	textRect := sdl.Rect{X: 0, Y: 0, W: textSurface.W, H: textSurface.H}
+	renderer.Copy(textTexture, nil, &textRect)
+}