Grimsace/RPG_City_Maker_Reborn
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fixed up comments

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Grimsace
2026-02-05 17:50:55 -06:00
parent 8d746d5c0b
commit 7440b000c1
8 changed files with 239 additions and 89 deletions
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terrain.go
+25 -12
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@@ -14,13 +14,16 @@ import (
"github.com/ojrac/opensimplex-go"
)
// Constants for Perlin noise generation
const (
alpha = 2.
beta = 2.
n = 3
)
// GenerateHeightmap creates a grayscale image representing the terrain's elevation using Perlin noise.
func GenerateHeightmap(width, height, octaves int, scale float64, seed int64) image.Image {
// Initialize Perlin noise generator
p := perlin.NewPerlin(alpha, beta, n, seed)
img := image.NewGray(image.Rect(0, 0, width, height))
@@ -28,6 +31,7 @@ func GenerateHeightmap(width, height, octaves int, scale float64, seed int64) im
scale = 100.0
}
// Use multiple goroutines to speed up noise generation
numGoroutines := runtime.NumCPU()
var wg sync.WaitGroup
rowsPerGoroutine := height / numGoroutines
@@ -43,6 +47,7 @@ func GenerateHeightmap(width, height, octaves int, scale float64, seed int64) im
defer wg.Done()
for y := startY; y < endY; y++ {
for x := 0; x < width; x++ {
// Combine multiple octaves of noise for more detail
var noise float64
frequency := 1.0
amplitude := 1.0
@@ -55,6 +60,7 @@ func GenerateHeightmap(width, height, octaves int, scale float64, seed int64) im
frequency *= 2.0
}
// Normalize the noise value and set the pixel color
noise /= maxAmplitude
grayColor := uint8((noise + 1) * 127.5)
img.SetGray(x, y, color.Gray{Y: grayColor})
@@ -67,11 +73,13 @@ func GenerateHeightmap(width, height, octaves int, scale float64, seed int64) im
return img
}
// ApplyRoughness adds a visual roughness effect to the heightmap.
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)
// The alpha value of the overlay determines the roughness effect
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)
@@ -91,11 +99,11 @@ func DarkenLakeAreas(heightmap image.Image, lakePixels []image.Point) image.Imag
lakeMask.Set(p.X, p.Y, black)
}
// Apply a Gaussian blur to the lake mask
// Apply a Gaussian blur to the lake mask to create smooth edges
blurRadius := float64(width) * 0.05
blurredLakeMask := imaging.Blur(lakeMask, blurRadius)
// Composite the blurred lake mask onto the heightmap with 50% opacity
// Composite the blurred lake mask onto the heightmap with some opacity
composite := image.NewRGBA(bounds)
draw.Draw(composite, bounds, heightmap, image.Point{}, draw.Src)
draw.DrawMask(composite, bounds, blurredLakeMask, image.Point{}, image.NewUniform(color.Alpha{192}), image.Point{}, draw.Over)
@@ -103,31 +111,33 @@ func DarkenLakeAreas(heightmap image.Image, lakePixels []image.Point) image.Imag
return composite
}
// FlattenRoadAreas smoothens the terrain under roads.
func FlattenRoadAreas(heightmap image.Image, roadPixels []image.Point) image.Image {
bounds := heightmap.Bounds()
width := bounds.Dx()
// Create a new image with the road pixels drawn on it.
// Create a mask with the road pixels
roadMask := image.NewGray(bounds)
for _, p := range roadPixels {
roadMask.SetGray(p.X, p.Y, color.Gray{Y: 255})
}
// Blur the road mask.
// Blur the road mask to create a smooth transition
blurRadius := float64(width) * 0.01
blurredRoadMask := imaging.Blur(roadMask, blurRadius)
// Create a new image to store the blurred heightmap.
// Blur the entire heightmap
blurredHeightmap := imaging.Blur(heightmap, blurRadius)
// Create a new composite image.
// Create a new composite image
composite := image.NewRGBA(bounds)
// Interpolate between the original and blurred heightmap based on the road mask
for y := bounds.Min.Y; y < bounds.Max.Y; y++ {
for x := bounds.Min.X; x < bounds.Max.X; x++ {
maskAlpha, _, _, _ := blurredRoadMask.At(x, y).RGBA()
if maskAlpha > 0 {
// Linearly interpolate between the original and blurred heightmap based on the mask alpha.
// Linearly interpolate between the original and blurred heightmap
originalColor := heightmap.At(x, y)
blurredColor := blurredHeightmap.At(x, y)
@@ -151,11 +161,12 @@ func FlattenRoadAreas(heightmap image.Image, roadPixels []image.Point) image.Ima
return composite
}
// GenerateTrees places trees on the map.
func GenerateTrees(img *image.RGBA, lakePixels, roadPixels, buildingPixels []image.Point, minTreeSize, maxTreeSize, treeCoverage, treeClumpiness float64, seed int64) []image.Point {
width := img.Bounds().Dx()
height := img.Bounds().Dy()
// 1. Calculate number of trees to place from coverage %.
// Step 1: Calculate the number of trees to place based on coverage percentage.
avgTreeSize := (minTreeSize + maxTreeSize) / 2
if avgTreeSize <= 0 {
return nil
@@ -172,7 +183,7 @@ func GenerateTrees(img *image.RGBA, lakePixels, roadPixels, buildingPixels []ima
return nil
}
// 2. Generate a simplex noise map for tree placement.
// Step 2: Generate a simplex noise map to guide tree placement.
noise := opensimplex.New(seed)
treeNoiseMap := image.NewGray(image.Rect(0, 0, width, height))
treeNoiseZoom := 0.05
@@ -185,6 +196,7 @@ func GenerateTrees(img *image.RGBA, lakePixels, roadPixels, buildingPixels []ima
}
threshold := uint8(255 * (1 - (treeCoverage / 100.0)))
// Create lookup maps for water, roads, and buildings for efficient collision detection
isLake := make(map[image.Point]bool)
for _, p := range lakePixels {
isLake[p] = true
@@ -202,7 +214,7 @@ func GenerateTrees(img *image.RGBA, lakePixels, roadPixels, buildingPixels []ima
randSrc := rand.New(rand.NewSource(seed))
// 3. Determine initial clump trees
// Step 3: Determine initial points for clumps of trees.
numClumpTrees := min(int(treeClumpiness), numTreesToPlace)
initialPoints := make([]image.Point, 0, numClumpTrees)
@@ -216,14 +228,14 @@ func GenerateTrees(img *image.RGBA, lakePixels, roadPixels, buildingPixels []ima
}
}
// 4. Place remaining trees using Bridson's Algorithm
// Step 4: Place remaining trees using Poisson Disc Sampling for a natural distribution.
minRadius := minTreeSize
allPoints := poissonDiscSampling(width, height, minRadius, 30, initialPoints, func(p image.Point) bool {
return treeNoiseMap.GrayAt(p.X, p.Y).Y >= threshold && !isLake[p] && !isRoad[p] && !isBuilding[p]
}, seed)
var treePixels []image.Point
// 5. Draw the trees.
// Step 5: Draw the trees on the image.
numGoroutines := runtime.NumCPU()
if len(allPoints) < numGoroutines {
numGoroutines = len(allPoints)
@@ -282,6 +294,7 @@ func GenerateTrees(img *image.RGBA, lakePixels, roadPixels, buildingPixels []ima
return treePixels
}
// poissonDiscSampling generates points that are randomly distributed but no closer than a given minimum radius.
func poissonDiscSampling(width, height int, minRadius float64, k int, initialPoints []image.Point, isValid func(image.Point) bool, seed int64) []image.Point {
randSrc := rand.New(rand.NewSource(seed))
points := initialPoints