From 072eba3e5a58ef08f015c57972df46aee38ca3a5 Mon Sep 17 00:00:00 2001
From: "Sascha L. Teichmann" <sascha.teichmann@intevation.de>
Date: Thu, 11 Sep 2014 02:28:09 +0200
Subject: [PATCH] Better early stopping when the tile is filled.

---
 tilemapper/main.go     |  9 ++++++---
 tilemapper/renderer.go | 42 +++++++++++++++++++++++-------------------
 2 files changed, 29 insertions(+), 22 deletions(-)

diff --git a/tilemapper/main.go b/tilemapper/main.go
index 041f18b..ae5a26d 100644
--- a/tilemapper/main.go
+++ b/tilemapper/main.go
@@ -72,8 +72,8 @@ func main() {
 
 	c1 := common.Coord{X: q1x, Z: q1z}
 	c2 := common.Coord{X: q2x, Z: q2z}
-	for c2.Y = q2y; c2.Y > q1y; c2.Y -= 16 {
-		c1.Y = c2.Y - 15
+	for c2.Y = q2y; c2.Y > q1y; c2.Y -= 8 {
+		c1.Y = c2.Y - 7
 		if c1.Y < q1y {
 			c1.Y = q1y
 		}
@@ -81,6 +81,9 @@ func main() {
 		if err = client.QueryCuboid(cuboid, drawBlock); err != nil {
 			log.Fatalf("query failed: %s", err)
 		}
+		if renderer.IsFilled() {
+			break
+		}
 	}
 
 	image := renderer.CreateImage(
@@ -90,6 +93,6 @@ func main() {
 		log.Fatalf("writing image failed: %s", err)
 	}
 
-	fmt.Printf("Rejected blocks: %d\n", renderer.RejectedBlocks)
 	fmt.Printf("num blocks: %d\n", numBlocks)
+	fmt.Printf("rejected blocks: %d\n", renderer.Rejected)
 }
diff --git a/tilemapper/renderer.go b/tilemapper/renderer.go
index 3bf8bb0..2e207fb 100644
--- a/tilemapper/renderer.go
+++ b/tilemapper/renderer.go
@@ -13,15 +13,14 @@ import (
 )
 
 type Renderer struct {
-	width          int
-	height         int
-	xOfs           int16
-	zOfs           int16
-	yBuffer        []int32
-	cBuffer        []int32
-	filled         []uint16
-	minYs          []int16
-	RejectedBlocks int
+	width    int
+	height   int
+	xOfs     int16
+	zOfs     int16
+	yBuffer  []int32
+	cBuffer  []int32
+	filled   int
+	Rejected int
 }
 
 func NewRenderer(xOfs, zOfs int16, width, height int) (renderer *Renderer) {
@@ -45,11 +44,10 @@ func NewRenderer(xOfs, zOfs int16, width, height int) (renderer *Renderer) {
 	return
 }
 
-func (r *Renderer) minY(x, z int16) (minY int32) {
-	x -= r.xOfs
-	z -= r.zOfs
-	w := r.width << 4
-	ofs := int(z)*w<<4 + int(x)<<4
+//func (r *Renderer) minY(x, z int16) (minY int32) {
+func (r *Renderer) minY(ofs, w int) (minY int32) {
+	//w := r.width << 4
+	//ofs := int(z)*w<<4 + int(x)<<4
 	minY = int32(math.MaxInt32)
 	for yEnd := ofs + w<<4; ofs < yEnd; {
 		for xEnd := ofs + 16; ofs < xEnd; ofs++ {
@@ -63,15 +61,21 @@ func (r *Renderer) minY(x, z int16) (minY int32) {
 	return
 }
 
+func (r *Renderer) IsFilled() bool {
+	return r.filled == r.width<<4*r.height<<4
+}
+
 func (r *Renderer) RenderBlock(block *common.Block, nameIndex map[string]int32) (err error) {
 
 	bx := block.Coord.X - r.xOfs
 	bz := block.Coord.Z - r.zOfs
 	// We do not need to render the block if the whole 16x16 area
 	// is already filled and the block is strictly below.
+	w := r.width << 4
+	ofs := int(bz)*w<<4 + int(bx)<<4
 	blockY := int32(block.Coord.Y) << 4
-	if blockY < r.minY(block.Coord.X, block.Coord.Z) {
-		r.RejectedBlocks++
+	if blockY < r.minY(ofs, w) {
+		r.Rejected++
 		return
 	}
 
@@ -81,14 +85,14 @@ func (r *Renderer) RenderBlock(block *common.Block, nameIndex map[string]int32)
 		return
 	}
 
-	w := r.width << 4
-
-	ofs := int(bz)*w<<4 + int(bx)<<4
 	for z := 0; z < 16; z++ {
 		for x := 0; x < 16; x++ {
 			if currentY := r.yBuffer[ofs]; currentY < blockY {
 				for y := 15; y >= 0; y-- {
 					if c, ok := db.Content(x, y, z); ok {
+						if r.cBuffer[ofs] == -1 {
+							r.filled++
+						}
 						r.cBuffer[ofs] = c
 						r.yBuffer[ofs] = blockY + int32(y)
 						break