From e145779ca0b077f10b788cc0bec47cffb9c15876 Mon Sep 17 00:00:00 2001
From: "Sascha L. Teichmann" <sascha.teichmann@intevation.de>
Date: Wed, 10 Sep 2014 01:21:55 +0200
Subject: [PATCH] Added incomplete renderer.

---
 tilemapper/blockdecoder.go | 17 ++++++++
 tilemapper/renderer.go     | 83 ++++++++++++++++++++++++++++++++++++++
 2 files changed, 100 insertions(+)
 create mode 100644 tilemapper/renderer.go

diff --git a/tilemapper/blockdecoder.go b/tilemapper/blockdecoder.go
index 1ab47ea..5c7b6fd 100644
--- a/tilemapper/blockdecoder.go
+++ b/tilemapper/blockdecoder.go
@@ -144,6 +144,23 @@ func NewDecodedBlock(data []byte, nameIndex map[string]int) (db *DecodedBlock, e
 	return
 }
 
+func (db *DecodedBlock) Content(x, y, z int) int {
+	pos := z<<8 + y<<4 + x
+
+	switch {
+	case db.Version >= 24:
+		pos <<= 1
+		return int(db.MapContent[pos])<<8 | int(db.MapContent[pos+1])
+	case db.Version >= 20:
+		if db.MapContent[pos] <= 0x80 {
+			return int(db.MapContent[pos])
+		}
+		return int(db.MapContent[pos])<<4 | int(db.MapContent[pos+0x2000])>>4
+	default:
+		return db.IgnoreId
+	}
+}
+
 func NewPosBuf(data []byte) *PosBuf {
 	return &PosBuf{Data: data}
 }
diff --git a/tilemapper/renderer.go b/tilemapper/renderer.go
new file mode 100644
index 0000000..7b05dca
--- /dev/null
+++ b/tilemapper/renderer.go
@@ -0,0 +1,83 @@
+// Copyright 2014 by Sascha L. Teichmann
+// Use of this source code is governed by the MIT license
+// that can be found in the LICENSE file.
+
+package main
+
+import (
+	"math"
+
+	"bitbucket.org/s_l_teichmann/mtredisalize/common"
+)
+
+type Renderer struct {
+	width   int
+	height  int
+	xOfs    int16
+	zOfs    int16
+	yBuffer []int32
+	cBuffer []int32
+	filled  []byte
+	minYs   []int16
+}
+
+func NewRenderer(xOfs, zOfs int16, width, height int) (renderer *Renderer) {
+	dim := width * height
+	pixSize := dim * 16 * 16
+	yBuffer := make([]int32, pixSize)
+	cBuffer := make([]int32, pixSize)
+	filled := make([]byte, dim)
+	minYs := make([]int16, dim)
+
+	for i := 0; i < pixSize; i++ {
+		yBuffer[i] = math.MinInt32
+		cBuffer[i] = -1
+	}
+
+	for i := 0; i < dim; i++ {
+		minYs[i] = math.MinInt16
+	}
+
+	renderer = &Renderer{
+		width:   width,
+		height:  height,
+		xOfs:    xOfs,
+		zOfs:    zOfs,
+		yBuffer: yBuffer,
+		cBuffer: cBuffer,
+		filled:  filled,
+		minYs:   minYs}
+	return
+}
+
+func (r *Renderer) RenderBlock(coord common.Coord, data []byte, nameIndex map[string]int) (err error) {
+	x := coord.X + r.xOfs
+	z := coord.Z + r.zOfs
+	dimIndex := (x << 4) + z
+	// We do not need to render the block if the whole 16x16 area
+	// is already filled and the block is strictly below.
+	if r.filled[dimIndex] == 0xff && r.minYs[dimIndex] > coord.Y {
+		return
+	}
+
+	var db *DecodedBlock
+	if db, err = NewDecodedBlock(data, nameIndex); err != nil {
+		return
+	}
+
+	_ = db
+
+	ay := int32(coord.Y) << 4
+
+	_ = ay
+
+	for x := 0; x < 16; x++ {
+		for z := 0; z < 16; z++ {
+			for y := 15; y >= 0; y-- {
+				_, _, _ = x, y, z
+			}
+		}
+	}
+
+	return
+}