Animating a nice backbuffer. Thank you Casey Muratori of Handmade Hero fame (https://www.youtube.com/watch?v=hNKU8Jiza2g)

ui/view.go

@@ -1,6 +1,11 @@
 package ui
 
 import (
+	"image"
+	"log"
+
+	"github.com/veandco/go-sdl2/sdl"
+
 	"gb-player/gb"
 )
 
@@ -12,3 +17,45 @@ type View struct {
 func NewView(controller *Controller, console *gb.Console) *View {
 	return &View{controller, console}
 }
+
+func (view *View) Update(dt uint64) {
+	console := view.console
+	renderer := view.controller.renderer
+
+	// console.StepMilliSeconds(dt)
+	console.StepMilliSeconds(sdl.GetTicks64())
+
+	buffer := console.Buffer()
+
+	drawBuffer(renderer, buffer)
+}
+
+func drawBuffer(renderer *sdl.Renderer, buffer *image.RGBA) {
+	width, height := gb.ConsoleWidth, gb.ConsoleHeight
+
+	imageTexture, err := renderer.CreateTexture(
+		uint32(sdl.PIXELFORMAT_RGBA32),
+		sdl.TEXTUREACCESS_STREAMING,
+		int32(width), int32(height))
+	if err != nil {
+		log.Fatal(err)
+	}
+	defer imageTexture.Destroy()
+
+	pixels, pitch, err := imageTexture.Lock(nil)
+	if err != nil {
+		log.Fatal(err)
+	}
+	for y := range height {
+		start := y * buffer.Stride
+		end := start + width*4
+		copy(pixels[y*pitch:y*pitch+width*4], buffer.Pix[start:end])
+	}
+	imageTexture.Unlock()
+
+	x := (windowWidth / 2) - width
+	y := (windowHeight / 2) - height
+	imageRect := sdl.Rect{X: int32(x), Y: int32(y), W: 2 * int32(width), H: 2 * int32(height)}
+
+	renderer.Copy(imageTexture, nil, &imageRect)
+}