split generation up into new tabs

This commit is contained in:
Grimsace
2026-02-02 10:15:26 -06:00
parent 1a71905da9
commit a3bf84a408
4 changed files with 521 additions and 517 deletions
-58
View File
@@ -1,58 +0,0 @@
package main
import (
"image"
"image/color"
"image/draw"
"github.com/aquilax/go-perlin"
)
const (
alpha = 2.
beta = 2.
n = 3
)
func GenerateHeightmap(width, height, octaves int, scale float64, seed int64) image.Image {
p := perlin.NewPerlin(alpha, beta, n, seed)
img := image.NewGray(image.Rect(0, 0, width, height))
if scale == 0 {
scale = 100.0
}
for x := 0; x < width; x++ {
for y := 0; y < height; y++ {
var noise float64
frequency := 1.0
amplitude := 1.0
maxAmplitude := 0.0
for i := 0; i < octaves; i++ {
noise += p.Noise2D(float64(x)*frequency/scale, float64(y)*frequency/scale) * amplitude
maxAmplitude += amplitude
amplitude /= 2.0
frequency *= 2.0
}
noise /= maxAmplitude
grayColor := uint8((noise + 1) * 127.5)
img.SetGray(x, y, color.Gray{Y: grayColor})
}
}
return img
}
func ApplyRoughness(heightmap image.Image, roughness float64) image.Image {
bounds := heightmap.Bounds()
composite := image.NewRGBA(bounds)
draw.Draw(composite, bounds, heightmap, image.Point{}, draw.Src)
alphaValue := 255 - uint8(roughness*2.55)
overlay := image.NewUniform(color.RGBA{R: 128, G: 128, B: 128, A: alphaValue})
draw.Draw(composite, bounds, overlay, image.Point{}, draw.Over)
return composite
}
+16 -12
View File
@@ -373,6 +373,20 @@ func main() {
detailSlider,
roughnessLabel,
roughnessSlider,
widget.NewLabel(""), // Spacer
minTreeSizeLabel,
minTreeSizeSlider,
maxTreeSizeLabel,
maxTreeSizeSlider,
treeCoverageLabel,
treeCoverageSlider,
treeClumpinessLabel,
treeClumpinessSlider,
))
waterTab := container.NewTabItem("Water", container.NewVBox(
lakesLabel,
lakesSlider,
lakeSizeLowerLabel,
@@ -390,17 +404,6 @@ func main() {
maxRiverWidthSlider,
riverCurvynessLabel,
riverCurvynessSlider,
widget.NewLabel(""), // Spacer
minTreeSizeLabel,
minTreeSizeSlider,
maxTreeSizeLabel,
maxTreeSizeSlider,
treeCoverageLabel,
treeCoverageSlider,
treeClumpinessLabel,
treeClumpinessSlider,
))
imageTab := container.NewTabItem("Image", container.NewVBox(
@@ -419,10 +422,11 @@ func main() {
tabs := container.NewAppTabs(
imageTab,
terrainTab,
waterTab,
)
left := container.NewVBox(
widget.NewLabel("Hello World!"),
widget.NewLabel("RPG City Maker Reborn"),
tabs,
)
+174 -447
View File
@@ -1,471 +1,64 @@
package main
import (
"container/heap"
"image"
"image/color"
"image/draw"
"math"
"math/rand"
"sort"
"github.com/aquilax/go-perlin"
"github.com/disintegration/imaging"
"github.com/ojrac/opensimplex-go"
)
// lakePixel represents a potential pixel to be added to a lake during growth
type lakePixel struct {
point image.Point
score float64
index int // required for heap.Interface
}
const (
alpha = 2.
beta = 2.
n = 3
)
type priorityQueue []*lakePixel
func GenerateHeightmap(width, height, octaves int, scale float64, seed int64) image.Image {
p := perlin.NewPerlin(alpha, beta, n, seed)
img := image.NewGray(image.Rect(0, 0, width, height))
func (pq priorityQueue) Len() int { return len(pq) }
func (pq priorityQueue) Less(i, j int) bool { return pq[i].score > pq[j].score } // Max-heap
func (pq priorityQueue) Swap(i, j int) {
pq[i], pq[j] = pq[j], pq[i]
pq[i].index = i
pq[j].index = j
}
func (pq *priorityQueue) Push(x interface{}) {
n := len(*pq)
item := x.(*lakePixel)
item.index = n
*pq = append(*pq, item)
}
func (pq *priorityQueue) Pop() interface{} {
old := *pq
n := len(old)
item := old[n-1]
old[n-1] = nil
item.index = -1
*pq = old[0 : n-1]
return item
}
func GenerateLakes(width, height, numLakes int, lakeSizeLower, lakeSizeUpper float64, heightmap image.Image, seed int64) (image.Image, [][]image.Point) {
canvas := image.NewRGBA(image.Rect(0, 0, width, height))
draw.Draw(canvas, canvas.Bounds(), image.NewUniform(color.White), image.Point{}, draw.Src)
if numLakes <= 0 || lakeSizeLower <= 0 {
return canvas, nil
if scale == 0 {
scale = 100.0
}
var allLakes [][]image.Point
randSrc := rand.New(rand.NewSource(seed))
// 1. Divide the image into a grid
gridDim := int(math.Ceil(math.Sqrt(float64(numLakes))))
if gridDim == 0 {
return canvas, nil
}
chunkWidth := width / gridDim
chunkHeight := height / gridDim
if chunkWidth == 0 || chunkHeight == 0 {
return canvas, nil
}
// 2. Create a list of chunk indices and shuffle them to randomize lake placement
chunkIndices := make([]int, gridDim*gridDim)
for i := range chunkIndices {
chunkIndices[i] = i
}
randSrc.Shuffle(len(chunkIndices), func(i, j int) {
chunkIndices[i], chunkIndices[j] = chunkIndices[j], chunkIndices[i]
})
totalArea := float64(width * height)
noiseGen := opensimplex.New(seed)
// 3. Generate a lake in a subset of the chunks
for i := 0; i < numLakes; i++ {
if i >= len(chunkIndices) {
break
}
var currentLake []image.Point
// Each lake gets a random size within the defined range
lakeSize := lakeSizeLower
if lakeSizeUpper > lakeSizeLower {
lakeSize = lakeSizeLower + randSrc.Float64()*(lakeSizeUpper-lakeSizeLower)
}
targetPixelsPerLake := int(math.Round(totalArea*(lakeSize/100.0))) / 2
if targetPixelsPerLake <= 0 {
targetPixelsPerLake = 1
}
chunkIndex := chunkIndices[i]
chunkGridX := chunkIndex % gridDim
chunkGridY := chunkIndex / gridDim
chunkRect := image.Rect(
chunkGridX*chunkWidth,
chunkGridY*chunkHeight,
(chunkGridX+1)*chunkWidth,
(chunkGridY+1)*chunkHeight,
)
// Use the growth algorithm within the chunk
pq := &priorityQueue{}
heap.Init(pq)
visited := make(map[image.Point]bool)
// Start near the center of the chunk
startPt := image.Point{
X: chunkRect.Min.X + chunkWidth/2,
Y: chunkRect.Min.Y + chunkHeight/2,
}
// just in case the center is out of bounds
if !startPt.In(chunkRect) {
continue
}
seedX := randSrc.Float64() * 10000.0
seedY := randSrc.Float64() * 10000.0
radius := math.Sqrt(float64(targetPixelsPerLake) / math.Pi)
noiseFreq := 0.01 + (0.2 / (radius + 1.0))
getScore := func(pt image.Point) float64 {
dx, dy := pt.X-startPt.X, pt.Y-startPt.Y
dist := math.Sqrt(float64(dx*dx + dy*dy))
noise := noiseGen.Eval2(seedX+float64(dx)*noiseFreq, seedY+float64(dy)*noiseFreq)
distPenalty := math.Pow(dist/radius, 3.0)
luma, _, _, _ := heightmap.At(pt.X, pt.Y).RGBA()
heightmapVal := float64(luma) / 65535.0
heightmapEffect := (0.5 - heightmapVal) * 1.5
return noise - distPenalty + heightmapEffect
}
heap.Push(pq, &lakePixel{point: startPt, score: getScore(startPt)})
visited[startPt] = true
lakeCount := 0
for pq.Len() > 0 && lakeCount < targetPixelsPerLake {
current := heap.Pop(pq).(*lakePixel)
// The pixel is valid, claim it.
canvas.Set(current.point.X, current.point.Y, color.RGBA{R: 0, G: 0, B: 255, A: 255})
currentLake = append(currentLake, current.point)
lakeCount++
// Add neighbors, constrained to the chunk rectangle
for dy := -1; dy <= 1; dy++ {
for dx := -1; dx <= 1; dx++ {
if dx == 0 && dy == 0 {
continue
}
neighbor := image.Point{X: current.point.X + dx, Y: current.point.Y + dy}
if !neighbor.In(chunkRect) || visited[neighbor] {
continue
}
visited[neighbor] = true
heap.Push(pq, &lakePixel{
point: neighbor,
score: getScore(neighbor),
})
}
}
}
if len(currentLake) > 0 {
allLakes = append(allLakes, currentLake)
}
}
return canvas, allLakes
}
type River struct {
Width float64
Start, End image.Point
Points []image.Point
}
func GenerateRivers(width, height, numRivers int, minWidth, maxWidth, curvyness float64, inputImage image.Image, lakes [][]image.Point, seed int64, heightmap image.Image) (image.Image, []image.Point) {
if numRivers == 0 {
return inputImage, nil
}
canvas, ok := inputImage.(*image.RGBA)
if !ok {
canvas = image.NewRGBA(inputImage.Bounds())
draw.Draw(canvas, canvas.Bounds(), inputImage, image.Point{}, draw.Src)
}
var allRiverPixels []image.Point
randSrc := rand.New(rand.NewSource(seed))
avgDim := float64(width+height) / 2.0
isWater := make(map[image.Point]bool)
lakePixelMap := make(map[image.Point]int)
for i, lake := range lakes {
for _, p := range lake {
isWater[p] = true
lakePixelMap[p] = i
}
}
rivers := make([]River, numRivers)
for i := 0; i < numRivers; i++ {
widthPercent := float64(i) / float64(numRivers-1)
if numRivers == 1 {
widthPercent = 0.5
}
rivers[i].Width = maxWidth - widthPercent*(maxWidth-minWidth)
}
sort.Slice(rivers, func(i, j int) bool {
return rivers[i].Width > rivers[j].Width
})
numControlPoints := int(avgDim * 0.03)
if numControlPoints < 60 {
numControlPoints = 60
}
for i := range rivers {
r := &rivers[i]
startEdge := randSrc.Intn(4)
endEdge := (startEdge + randSrc.Intn(3) + 1) % 4
r.Start = getPointOnEdge(width, height, startEdge, randSrc)
r.End = getPointOnEdge(width, height, endEdge, randSrc)
path := calculatePath(r.Start, r.End, curvyness/100.0, avgDim, randSrc, numControlPoints)
for _, p := range path {
if isWater[p] {
if lakeIndex, isLake := lakePixelMap[p]; isLake {
// Intersection is with a lake, find its center
lakeCenter := findCenter(lakes[lakeIndex])
r.End = lakeCenter
} else {
// Intersection is with another river
r.End = p
}
path = calculatePath(r.Start, r.End, curvyness/100.0, avgDim, randSrc, numControlPoints)
break
}
}
riverWidthPx := (r.Width / 100.0) * avgDim
radius := riverWidthPx / 2.0
for _, p := range path {
// When drawing river pixels, add them to isWater to detect river-river intersections
drawCircle(canvas, p, radius, color.RGBA{R: 0, G: 0, B: 255, A: 255}, &allRiverPixels, isWater, heightmap)
}
r.Points = path
}
return canvas, allRiverPixels
}
func findCenter(pixels []image.Point) image.Point {
if len(pixels) == 0 {
return image.Point{}
}
var sumX, sumY int
for _, p := range pixels {
sumX += p.X
sumY += p.Y
}
return image.Point{
X: sumX / len(pixels),
Y: sumY / len(pixels),
}
}
func getPointOnEdge(width, height, edge int, randSrc *rand.Rand) image.Point {
switch edge {
case 0: // Top
return image.Point{X: randSrc.Intn(width), Y: 0}
case 1: // Right
return image.Point{X: width - 1, Y: randSrc.Intn(height)}
case 2: // Bottom
return image.Point{X: randSrc.Intn(width), Y: height - 1}
default: // Left
return image.Point{X: 0, Y: randSrc.Intn(height)}
}
}
func calculatePath(start, end image.Point, curvyness, avgDim float64, randSrc *rand.Rand, numControlPoints int) []image.Point {
dx := end.X - start.X
dy := end.Y - start.Y
dist := math.Sqrt(float64(dx*dx + dy*dy))
if dist == 0 {
return []image.Point{start}
}
if curvyness == 0 {
return bresenham([]image.Point{start, end})
}
type wave struct {
amplitude float64
numWaves float64
phase float64
}
waves := make([]wave, 3)
amp := (avgDim / 10.0) * curvyness
mainWavelength := avgDim / 4.0
if mainWavelength < 1 {
mainWavelength = 1
}
baseNumWaves := (dist / mainWavelength) * curvyness
for i := 0; i < 3; i++ {
freqMultiplier := 1.0 + float64(i)
randomizedNumWaves := baseNumWaves * freqMultiplier * (0.75 + randSrc.Float64()*0.5)
waves[i] = wave{
amplitude: amp,
numWaves: randomizedNumWaves,
phase: randSrc.Float64() * 2 * math.Pi,
}
amp /= 3
}
controlPoints := make([]image.Point, numControlPoints+1)
for i := 0; i <= numControlPoints; i++ {
t := float64(i) / float64(numControlPoints)
x := float64(start.X) + t*float64(dx)
y := float64(start.Y) + t*float64(dy)
perpX, perpY := -float64(dy)/dist, float64(dx)/dist
totalOffset := 0.0
for _, w := range waves {
totalOffset += math.Sin(t*w.numWaves*2*math.Pi+w.phase) * w.amplitude
}
// Apply an envelope to ensure start/end points are anchored
totalOffset *= math.Sin(t * math.Pi)
x += totalOffset * perpX
y += totalOffset * perpY
controlPoints[i] = image.Point{X: int(math.Round(x)), Y: int(math.Round(y))}
}
return bresenham(controlPoints)
}
func bresenham(path []image.Point) []image.Point {
if len(path) < 2 {
return path
}
var fullPath []image.Point
for i := 0; i < len(path)-1; i++ {
p1, p2 := path[i], path[i+1]
dx, dy := p2.X-p1.X, p2.Y-p1.Y
absDx, absDy := int(math.Abs(float64(dx))), int(math.Abs(float64(dy)))
sx, sy := 1, 1
if dx < 0 {
sx = -1
}
if dy < 0 {
sy = -1
}
err := absDx - absDy
x, y := p1.X, p1.Y
for {
fullPath = append(fullPath, image.Point{X: x, Y: y})
if x == p2.X && y == p2.Y {
break
}
e2 := 2 * err
if e2 > -absDy {
err -= absDy
x += sx
}
if e2 < absDx {
err += absDx
y += sy
}
}
}
return fullPath
}
func drawCircle(img *image.RGBA, center image.Point, radius float64, c color.Color, pixels *[]image.Point, isWater map[image.Point]bool, heightmap image.Image) {
bounds := img.Bounds()
r2 := radius * radius
innerRadius := radius * 0.875 // The inner 75% of the river is smooth
innerR2 := innerRadius * innerRadius
for y := int(math.Floor(float64(center.Y) - radius)); y <= int(math.Ceil(float64(center.Y)+radius)); y++ {
for x := int(math.Floor(float64(center.X) - radius)); x <= int(math.Ceil(float64(center.X)+radius)); x++ {
p := image.Point{X: x, Y: y}
if !p.In(bounds) {
continue
for x := 0; x < width; x++ {
for y := 0; y < height; y++ {
var noise float64
frequency := 1.0
amplitude := 1.0
maxAmplitude := 0.0
for i := 0; i < octaves; i++ {
noise += p.Noise2D(float64(x)*frequency/scale, float64(y)*frequency/scale) * amplitude
maxAmplitude += amplitude
amplitude /= 2.0
frequency *= 2.0
}
dx, dy := float64(x-center.X), float64(y-center.Y)
dist2 := dx*dx + dy*dy
if dist2 <= r2 {
if !isWater[p] {
// Roughen the outer 15% of the river
if dist2 > innerR2 {
luma, _, _, _ := heightmap.At(x, y).RGBA()
// Normalize luma to 0-1 range
heightmapVal := float64(luma) / 65535.0
// Roughen the edges based on the heightmap
if heightmapVal < 0.5 {
continue
}
}
img.Set(x, y, c)
*pixels = append(*pixels, p)
isWater[p] = true
}
}
noise /= maxAmplitude
grayColor := uint8((noise + 1) * 127.5)
img.SetGray(x, y, color.Gray{Y: grayColor})
}
}
return img
}
func ApplyRoughness(heightmap image.Image, roughness float64) image.Image {
bounds := heightmap.Bounds()
composite := image.NewRGBA(bounds)
draw.Draw(composite, bounds, heightmap, image.Point{}, draw.Src)
alphaValue := 255 - uint8(roughness*2.55)
overlay := image.NewUniform(color.RGBA{R: 128, G: 128, B: 128, A: alphaValue})
draw.Draw(composite, bounds, overlay, image.Point{}, draw.Over)
return composite
}
// DarkenLakeAreas applies a visual darkening effect to the heightmap where lakes exist.
@@ -648,3 +241,137 @@ func poissonDiscSampling(width, height int, minRadius float64, k int, initialPoi
}
return points
}
func bresenham(path []image.Point) []image.Point {
if len(path) < 2 {
return path
}
var fullPath []image.Point
for i := 0; i < len(path)-1; i++ {
p1, p2 := path[i], path[i+1]
dx, dy := p2.X-p1.X, p2.Y-p1.Y
absDx, absDy := int(math.Abs(float64(dx))), int(math.Abs(float64(dy)))
sx, sy := 1, 1
if dx < 0 {
sx = -1
}
if dy < 0 {
sy = -1
}
err := absDx - absDy
x, y := p1.X, p1.Y
for {
fullPath = append(fullPath, image.Point{X: x, Y: y})
if x == p2.X && y == p2.Y {
break
}
e2 := 2 * err
if e2 > -absDy {
err -= absDy
x += sx
}
if e2 < absDx {
err += absDx
y += sy
}
}
}
return fullPath
}
func calculatePath(start, end image.Point, curvyness, avgDim float64, randSrc *rand.Rand, numControlPoints int) []image.Point {
dx := end.X - start.X
dy := end.Y - start.Y
dist := math.Sqrt(float64(dx*dx + dy*dy))
if dist == 0 {
return []image.Point{start}
}
if curvyness == 0 {
return bresenham([]image.Point{start, end})
}
type wave struct {
amplitude float64
numWaves float64
phase float64
}
waves := make([]wave, 3)
amp := (avgDim / 10.0) * curvyness
mainWavelength := avgDim / 4.0
if mainWavelength < 1 {
mainWavelength = 1
}
baseNumWaves := (dist / mainWavelength) * curvyness
for i := 0; i < 3; i++ {
freqMultiplier := 1.0 + float64(i)
randomizedNumWaves := baseNumWaves * freqMultiplier * (0.75 + randSrc.Float64()*0.5)
waves[i] = wave{
amplitude: amp,
numWaves: randomizedNumWaves,
phase: randSrc.Float64() * 2 * math.Pi,
}
amp /= 3
}
controlPoints := make([]image.Point, numControlPoints+1)
for i := 0; i <= numControlPoints; i++ {
t := float64(i) / float64(numControlPoints)
x := float64(start.X) + t*float64(dx)
y := float64(start.Y) + t*float64(dy)
perpX, perpY := -float64(dy)/dist, float64(dx)/dist
totalOffset := 0.0
for _, w := range waves {
totalOffset += math.Sin(t*w.numWaves*2*math.Pi+w.phase) * w.amplitude
}
// Apply an envelope to ensure start/end points are anchored
totalOffset *= math.Sin(t * math.Pi)
x += totalOffset * perpX
y += totalOffset * perpY
controlPoints[i] = image.Point{X: int(math.Round(x)), Y: int(math.Round(y))}
}
return bresenham(controlPoints)
}
+331
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@@ -0,0 +1,331 @@
package main
import (
"container/heap"
"image"
"image/color"
"image/draw"
"math"
"math/rand"
"sort"
"github.com/ojrac/opensimplex-go"
)
// lakePixel represents a potential pixel to be added to a lake during growth
type lakePixel struct {
point image.Point
score float64
index int // required for heap.Interface
}
type priorityQueue []*lakePixel
func (pq priorityQueue) Len() int { return len(pq) }
func (pq priorityQueue) Less(i, j int) bool { return pq[i].score > pq[j].score } // Max-heap
func (pq priorityQueue) Swap(i, j int) {
pq[i], pq[j] = pq[j], pq[i]
pq[i].index = i
pq[j].index = j
}
func (pq *priorityQueue) Push(x interface{}) {
n := len(*pq)
item := x.(*lakePixel)
item.index = n
*pq = append(*pq, item)
}
func (pq *priorityQueue) Pop() interface{} {
old := *pq
n := len(old)
item := old[n-1]
old[n-1] = nil
item.index = -1
*pq = old[0 : n-1]
return item
}
func GenerateLakes(width, height, numLakes int, lakeSizeLower, lakeSizeUpper float64, heightmap image.Image, seed int64) (image.Image, [][]image.Point) {
canvas := image.NewRGBA(image.Rect(0, 0, width, height))
draw.Draw(canvas, canvas.Bounds(), image.NewUniform(color.White), image.Point{}, draw.Src)
if numLakes <= 0 || lakeSizeLower <= 0 {
return canvas, nil
}
var allLakes [][]image.Point
randSrc := rand.New(rand.NewSource(seed))
// 1. Divide the image into a grid
gridDim := int(math.Ceil(math.Sqrt(float64(numLakes))))
if gridDim == 0 {
return canvas, nil
}
chunkWidth := width / gridDim
chunkHeight := height / gridDim
if chunkWidth == 0 || chunkHeight == 0 {
return canvas, nil
}
// 2. Create a list of chunk indices and shuffle them to randomize lake placement
chunkIndices := make([]int, gridDim*gridDim)
for i := range chunkIndices {
chunkIndices[i] = i
}
randSrc.Shuffle(len(chunkIndices), func(i, j int) {
chunkIndices[i], chunkIndices[j] = chunkIndices[j], chunkIndices[i]
})
totalArea := float64(width * height)
noiseGen := opensimplex.New(seed)
// 3. Generate a lake in a subset of the chunks
for i := 0; i < numLakes; i++ {
if i >= len(chunkIndices) {
break
}
var currentLake []image.Point
// Each lake gets a random size within the defined range
lakeSize := lakeSizeLower
if lakeSizeUpper > lakeSizeLower {
lakeSize = lakeSizeLower + randSrc.Float64()*(lakeSizeUpper-lakeSizeLower)
}
targetPixelsPerLake := int(math.Round(totalArea*(lakeSize/100.0))) / 2
if targetPixelsPerLake <= 0 {
targetPixelsPerLake = 1
}
chunkIndex := chunkIndices[i]
chunkGridX := chunkIndex % gridDim
chunkGridY := chunkIndex / gridDim
chunkRect := image.Rect(
chunkGridX*chunkWidth,
chunkGridY*chunkHeight,
(chunkGridX+1)*chunkWidth,
(chunkGridY+1)*chunkHeight,
)
// Use the growth algorithm within the chunk
pq := &priorityQueue{}
heap.Init(pq)
visited := make(map[image.Point]bool)
// Start near the center of the chunk
startPt := image.Point{
X: chunkRect.Min.X + chunkWidth/2,
Y: chunkRect.Min.Y + chunkHeight/2,
}
// just in case the center is out of bounds
if !startPt.In(chunkRect) {
continue
}
seedX := randSrc.Float64() * 10000.0
seedY := randSrc.Float64() * 10000.0
radius := math.Sqrt(float64(targetPixelsPerLake) / math.Pi)
noiseFreq := 0.01 + (0.2 / (radius + 1.0))
getScore := func(pt image.Point) float64 {
dx, dy := pt.X-startPt.X, pt.Y-startPt.Y
dist := math.Sqrt(float64(dx*dx + dy*dy))
noise := noiseGen.Eval2(seedX+float64(dx)*noiseFreq, seedY+float64(dy)*noiseFreq)
distPenalty := math.Pow(dist/radius, 3.0)
luma, _, _, _ := heightmap.At(pt.X, pt.Y).RGBA()
heightmapVal := float64(luma) / 65535.0
heightmapEffect := (0.5 - heightmapVal) * 1.5
return noise - distPenalty + heightmapEffect
}
heap.Push(pq, &lakePixel{point: startPt, score: getScore(startPt)})
visited[startPt] = true
lakeCount := 0
for pq.Len() > 0 && lakeCount < targetPixelsPerLake {
current := heap.Pop(pq).(*lakePixel)
// The pixel is valid, claim it.
canvas.Set(current.point.X, current.point.Y, color.RGBA{R: 0, G: 0, B: 255, A: 255})
currentLake = append(currentLake, current.point)
lakeCount++
// Add neighbors, constrained to the chunk rectangle
for dy := -1; dy <= 1; dy++ {
for dx := -1; dx <= 1; dx++ {
if dx == 0 && dy == 0 {
continue
}
neighbor := image.Point{X: current.point.X + dx, Y: current.point.Y + dy}
if !neighbor.In(chunkRect) || visited[neighbor] {
continue
}
visited[neighbor] = true
heap.Push(pq, &lakePixel{
point: neighbor,
score: getScore(neighbor),
})
}
}
}
if len(currentLake) > 0 {
allLakes = append(allLakes, currentLake)
}
}
return canvas, allLakes
}
type River struct {
Width float64
Start, End image.Point
Points []image.Point
}
func GenerateRivers(width, height, numRivers int, minWidth, maxWidth, curvyness float64, inputImage image.Image, lakes [][]image.Point, seed int64, heightmap image.Image) (image.Image, []image.Point) {
if numRivers == 0 {
return inputImage, nil
}
canvas, ok := inputImage.(*image.RGBA)
if !ok {
canvas = image.NewRGBA(inputImage.Bounds())
draw.Draw(canvas, canvas.Bounds(), inputImage, image.Point{}, draw.Src)
}
var allRiverPixels []image.Point
randSrc := rand.New(rand.NewSource(seed))
avgDim := float64(width+height) / 2.0
isWater := make(map[image.Point]bool)
lakePixelMap := make(map[image.Point]int)
for i, lake := range lakes {
for _, p := range lake {
isWater[p] = true
lakePixelMap[p] = i
}
}
rivers := make([]River, numRivers)
for i := 0; i < numRivers; i++ {
widthPercent := float64(i) / float64(numRivers-1)
if numRivers == 1 {
widthPercent = 0.5
}
rivers[i].Width = maxWidth - widthPercent*(maxWidth-minWidth)
}
sort.Slice(rivers, func(i, j int) bool {
return rivers[i].Width > rivers[j].Width
})
numControlPoints := int(avgDim * 0.03)
if numControlPoints < 60 {
numControlPoints = 60
}
for i := range rivers {
r := &rivers[i]
startEdge := randSrc.Intn(4)
endEdge := (startEdge + randSrc.Intn(3) + 1) % 4
r.Start = getPointOnEdge(width, height, startEdge, randSrc)
r.End = getPointOnEdge(width, height, endEdge, randSrc)
path := calculatePath(r.Start, r.End, curvyness/100.0, avgDim, randSrc, numControlPoints)
for _, p := range path {
if isWater[p] {
if lakeIndex, isLake := lakePixelMap[p]; isLake {
// Intersection is with a lake, find its center
lakeCenter := findCenter(lakes[lakeIndex])
r.End = lakeCenter
} else {
// Intersection is with another river
r.End = p
}
path = calculatePath(r.Start, r.End, curvyness/100.0, avgDim, randSrc, numControlPoints)
break
}
}
riverWidthPx := (r.Width / 100.0) * avgDim
radius := riverWidthPx / 2.0
for _, p := range path {
// When drawing river pixels, add them to isWater to detect river-river intersections
drawCircle(canvas, p, radius, color.RGBA{R: 0, G: 0, B: 255, A: 255}, &allRiverPixels, isWater, heightmap)
}
r.Points = path
}
return canvas, allRiverPixels
}
func findCenter(pixels []image.Point) image.Point {
if len(pixels) == 0 {
return image.Point{}
}
var sumX, sumY int
for _, p := range pixels {
sumX += p.X
sumY += p.Y
}
return image.Point{
X: sumX / len(pixels),
Y: sumY / len(pixels),
}
}
func getPointOnEdge(width, height, edge int, randSrc *rand.Rand) image.Point {
switch edge {
case 0: // Top
return image.Point{X: randSrc.Intn(width), Y: 0}
case 1: // Right
return image.Point{X: width - 1, Y: randSrc.Intn(height)}
case 2: // Bottom
return image.Point{X: randSrc.Intn(width), Y: height - 1}
default: // Left
return image.Point{X: 0, Y: randSrc.Intn(height)}
}
}
func drawCircle(img *image.RGBA, center image.Point, radius float64, c color.Color, pixels *[]image.Point, isWater map[image.Point]bool, heightmap image.Image) {
bounds := img.Bounds()
r2 := radius * radius
innerRadius := radius * 0.875 // The inner 75% of the river is smooth
innerR2 := innerRadius * innerRadius
for y := int(math.Floor(float64(center.Y) - radius)); y <= int(math.Ceil(float64(center.Y)+radius)); y++ {
for x := int(math.Floor(float64(center.X) - radius)); x <= int(math.Ceil(float64(center.X)+radius)); x++ {
p := image.Point{X: x, Y: y}
if !p.In(bounds) {
continue
}
dx, dy := float64(x-center.X), float64(y-center.Y)
dist2 := dx*dx + dy*dy
if dist2 <= r2 {
if !isWater[p] {
// Roughen the outer 15% of the river
if dist2 > innerR2 {
luma, _, _, _ := heightmap.At(x, y).RGBA()
// Normalize luma to 0-1 range
heightmapVal := float64(luma) / 65535.0
// Roughen the edges based on the heightmap
if heightmapVal < 0.5 {
continue
}
}
img.Set(x, y, c)
*pixels = append(*pixels, p)
isWater[p] = true
}
}
}
}
}