mtsatellite/tilemapper/renderer.go

128 lines
2.6 KiB
Go

// 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 (
"image"
"image/color"
"math"
"bitbucket.org/s_l_teichmann/mtredisalize/common"
)
type Renderer struct {
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) {
dim := width * height
pixSize := dim * 16 * 16
yBuffer := make([]int32, pixSize)
cBuffer := make([]int32, pixSize)
for i := 0; i < pixSize; i++ {
yBuffer[i] = math.MinInt32
cBuffer[i] = -1
}
renderer = &Renderer{
width: width,
height: height,
xOfs: xOfs,
zOfs: zOfs,
yBuffer: yBuffer,
cBuffer: cBuffer}
return
}
func (r *Renderer) minY(ofs, w int) (minY int32, filled bool) {
minY = int32(math.MaxInt32)
for yEnd := ofs + w<<4; ofs < yEnd; {
for xEnd := ofs + 16; ofs < xEnd; ofs++ {
y := r.yBuffer[ofs]
switch {
case y == math.MaxInt32:
return
case y < minY:
minY = y
}
}
ofs += w - 16
}
filled = true
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 minY, filled := r.minY(ofs, w); filled && blockY < minY {
r.Rejected++
return
}
// Decoding is pretty expensive so it that late.
var db *DecodedBlock
if db, err = NewDecodedBlock(block.Data, nameIndex); err != nil {
return
}
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
}
}
}
ofs++
}
ofs += w - 16
}
return
}
func (r *Renderer) CreateImage(colors []color.RGBA, background color.RGBA) *image.RGBA {
pw, ph := r.width<<4, r.height<<4
image := image.NewRGBA(image.Rect(0, 0, pw, ph))
ofs, numCols := 0, int32(len(colors))
for z := ph - 1; z >= 0; z-- {
for x := 0; x < pw; x++ {
colIdx := r.cBuffer[ofs]
if colIdx >= 0 && colIdx < numCols {
image.Set(x, z, colors[colIdx])
} else {
image.Set(x, z, background)
}
ofs++
}
}
return image
}