Improved performance of Renderer.Reset by factor of 2.

common/renderer.go

@@ -152,20 +152,31 @@ func (r *Renderer) SetPos(xOfs, zOfs int16) {
 }
 
 func (r *Renderer) Reset() {
-	for i, n := 0, len(r.yBuffer); i < n; i++ {
-		r.yBuffer[i] = math.MinInt32
-		r.cBuffer[i] = -1
+	yb := r.yBuffer
+	yb = yb[:len(yb)]
+	for i := range yb {
+		yb[i] = math.MinInt32
 	}
-	for i, n := 0, len(r.yMin); i < n; i++ {
-		r.yMin[i] = math.MinInt32
+
+	cb := r.cBuffer
+	cb = cb[:len(cb)]
+	for i := range cb {
+		cb[i] = -1
+	}
+
+	ym := r.yMin
+	ym = ym[:len(ym)]
+	for i := range ym {
+		ym[i] = math.MinInt32
 	}
 
 	if r.TransparentBlocks > 0 {
 		r.TransparentBlocks = 0
-		for i, t := range r.tBuffer {
+		tb := r.tBuffer
+		for i, t := range tb {
 			if t != nil {
 				r.spans.FreeAll(t)
-				r.tBuffer[i] = nil
+				tb[i] = nil
 			}
 		}
 	}