Combine batched/un-batched sprite structs

tools/benchmark/sprite_bench.go

@@ -50,6 +50,7 @@ func newSpriteStatic(win *opengl.Window) (Benchmark, error) {
 	width := bounds.W()
 	height := bounds.H()
 	rows, cols := 32, 32
+
 	benchmark := &spriteStatic{
 		sprite: sprite,
 		rows:   rows,
@@ -59,51 +60,36 @@ func newSpriteStatic(win *opengl.Window) (Benchmark, error) {
 	return benchmark, nil
 }
 
-type spriteStatic struct {
-	sprite     *pixel.Sprite
-	rows, cols int
-	cell       pixel.Vec
-}
-
-func (ss *spriteStatic) Step(win *opengl.Window) {
-	win.Clear(backgroundColor)
-	spriteGrid(ss.sprite, win, ss.rows, ss.cols, ss.cell)
-}
-
 func newSpriteStaticBatched(win *opengl.Window) (Benchmark, error) {
-	sprite, err := loadSprite(logoPath, logoFrame)
+	benchmark, err := newSpriteStatic(win)
 	if err != nil {
 		return nil, err
 	}
-
-	bounds := win.Bounds()
-	width := bounds.W()
-	height := bounds.H()
-	rows, cols := 32, 32
-
-	benchmark := &spriteStaticBatched{
-		sprite: sprite,
-		batch:  pixel.NewBatch(&pixel.TrianglesData{}, sprite.Picture()),
-		rows:   rows,
-		cols:   cols,
-		cell:   gridCell(width, height, rows, cols),
-	}
-
-	return benchmark, nil
+	ss := benchmark.(*spriteStatic)
+	ss.batch = pixel.NewBatch(&pixel.TrianglesData{}, ss.sprite.Picture())
+	return ss, nil
 }
 
-type spriteStaticBatched struct {
+type spriteStatic struct {
 	sprite     *pixel.Sprite
-	batch      *pixel.Batch
 	rows, cols int
 	cell       pixel.Vec
+	batch      *pixel.Batch
 }
 
-func (ssb *spriteStaticBatched) Step(win *opengl.Window) {
+func (ss *spriteStatic) Step(win *opengl.Window) {
 	win.Clear(backgroundColor)
-	ssb.batch.Clear()
-	spriteGrid(ssb.sprite, ssb.batch, ssb.rows, ssb.cols, ssb.cell)
-	ssb.batch.Draw(win)
+	var target pixel.Target
+	if ss.batch != nil {
+		ss.batch.Clear()
+		target = ss.batch
+	} else {
+		target = win
+	}
+	spriteGrid(ss.sprite, target, ss.rows, ss.cols, ss.cell)
+	if ss.batch != nil {
+		ss.batch.Draw(win)
+	}
 }
 
 func spriteGrid(sprite *pixel.Sprite, target pixel.Target, rows, cols int, cell pixel.Vec) {