implemented png export so that we get a overlay of the splitt lines and also directly export a node tree visualization of the node tree with graphviz.

internal/viz/dot.go

@@ -5,6 +5,7 @@ import (
 	"bytes"
 	"fmt"
 	"os"
+	"os/exec"
 )
 
 // EmitDOT serialisiert den BSP-Baum mit Wurzel root und schreibt ihn als DOT-Datei nach path.
@@ -39,3 +40,12 @@ func EmitDOT(root *bsp.Node, path string) error {
 	buf.WriteString("}\n")
 	return os.WriteFile(path, buf.Bytes(), 0644)
 }
+
+func RunGraphviz(dotFile, pngFile string) error {
+	cmd := exec.Command("dot", "-Tpng", dotFile, "-o", pngFile)
+	out, err := cmd.CombinedOutput()
+	if err != nil {
+		return fmt.Errorf("graphviz failed: %v\n%s", err, string(out))
+	}
+	return nil
+}

internal/viz/png.go

@@ -1,3 +1,177 @@
 package viz
 
-//init
+import (
+	"bspviz/internal/bsp"
+	"bspviz/internal/geom"
+	"bspviz/internal/mapfmt"
+	"image"
+	"image/color"
+	"image/png"
+	"math"
+	"math/rand"
+	"os"
+	"time"
+)
+
+// worldToScreen transformiert Doom-Koordinaten in Bildkoordinaten
+type worldToScreen struct {
+	minX, minY float64
+	scale      float64
+	W, H       int
+	margin     float64
+}
+
+func makeTransform(verts []mapfmt.Vertex, W, H int) worldToScreen {
+	minX, minY := math.MaxFloat64, math.MaxFloat64
+	maxX, maxY := -math.MaxFloat64, -math.MaxFloat64
+	for _, v := range verts {
+		x, y := float64(v.X), float64(v.Y)
+		if x < minX {
+			minX = x
+		}
+		if y < minY {
+			minY = y
+		}
+		if x > maxX {
+			maxX = x
+		}
+		if y > maxY {
+			maxY = y
+		}
+	}
+	margin := 20.0
+	w := maxX - minX
+	h := maxY - minY
+	if w < 1 {
+		w = 1
+	}
+	if h < 1 {
+		h = 1
+	}
+	scale := math.Min((float64(W)-2*margin)/w, (float64(H)-2*margin)/h)
+	return worldToScreen{minX, minY, scale, W, H, margin}
+}
+
+func (t worldToScreen) P(p geom.Vec) (int, int) {
+	x := t.margin + (p.X-t.minX)*t.scale
+	y := t.margin + (p.Y-t.minY)*t.scale
+	// Y-Achse flippen (Doom: +Y nach oben, Bild: +Y nach unten)
+	yy := float64(t.H) - y
+	return int(x + 0.5), int(yy + 0.5)
+}
+
+// einfache Bresenham-Linie
+func drawLine(img *image.RGBA, x0, y0, x1, y1 int, c color.Color) {
+	dx := int(math.Abs(float64(x1 - x0)))
+	dy := -int(math.Abs(float64(y1 - y0)))
+	sx := -1
+	if x0 < x1 {
+		sx = 1
+	}
+	sy := -1
+	if y0 < y1 {
+		sy = 1
+	}
+	err := dx + dy
+	for {
+		if x0 >= 0 && y0 >= 0 && x0 < img.Bounds().Dx() && y0 < img.Bounds().Dy() {
+			img.Set(x0, y0, c)
+		}
+		if x0 == x1 && y0 == y1 {
+			break
+		}
+		e2 := 2 * err
+		if e2 >= dy {
+			err += dy
+			x0 += sx
+		}
+		if e2 <= dx {
+			err += dx
+			y0 += sy
+		}
+	}
+}
+
+// RenderPNG zeichnet die Map und den BSP-Baum
+func RenderPNG(m *mapfmt.MapData, root *bsp.Node, outPath string) error {
+	W, H := 1200, 900
+	img := image.NewRGBA(image.Rect(0, 0, W, H))
+
+	// Hintergrund
+	bg := color.RGBA{20, 20, 24, 255}
+	for y := 0; y < H; y++ {
+		for x := 0; x < W; x++ {
+			img.Set(x, y, bg)
+		}
+	}
+
+	tr := makeTransform(m.Vertices, W, H)
+
+	// 1) Linedefs grau
+	gray := color.RGBA{180, 180, 180, 255}
+	for _, L := range m.Linedefs {
+		a := m.Vertices[L.V1]
+		b := m.Vertices[L.V2]
+		x0, y0 := tr.P(geom.V(float64(a.X), float64(a.Y)))
+		x1, y1 := tr.P(geom.V(float64(b.X), float64(b.Y)))
+		drawLine(img, x0, y0, x1, y1, gray)
+	}
+
+	// 2) Split-Linien (gelb)
+	yellow := color.RGBA{240, 210, 40, 255}
+	var drawSplits func(*bsp.Node)
+	drawSplits = func(n *bsp.Node) {
+		if n == nil || n.Leaf != nil {
+			return
+		}
+		D := n.D
+		L := geom.Len(D)
+		if L < 1e-9 {
+			return
+		}
+		dx, dy := D.X/L, D.Y/L
+		k := 1e6 // "lange" Linie
+		p0 := geom.V(n.O.X-k*dx, n.O.Y-k*dy)
+		p1 := geom.V(n.O.X+k*dx, n.O.Y+k*dy)
+		x0, y0 := tr.P(p0)
+		x1, y1 := tr.P(p1)
+		drawLine(img, x0, y0, x1, y1, yellow)
+		drawSplits(n.Left)
+		drawSplits(n.Right)
+	}
+	drawSplits(root)
+
+	// 3) Leaves farbig
+	rng := rand.New(rand.NewSource(time.Now().UnixNano()))
+	var paintLeaves func(*bsp.Node)
+	paintLeaves = func(n *bsp.Node) {
+		if n == nil {
+			return
+		}
+		if n.Leaf != nil {
+			col := color.RGBA{
+				uint8(100 + rng.Intn(100)),
+				uint8(100 + rng.Intn(100)),
+				uint8(100 + rng.Intn(100)),
+				255,
+			}
+			for _, s := range n.Leaf.Segs {
+				x0, y0 := tr.P(s.A)
+				x1, y1 := tr.P(s.B)
+				drawLine(img, x0, y0, x1, y1, col)
+			}
+			return
+		}
+		paintLeaves(n.Left)
+		paintLeaves(n.Right)
+	}
+	paintLeaves(root)
+
+	// speichern
+	f, err := os.Create(outPath)
+	if err != nil {
+		return err
+	}
+	defer f.Close()
+	return png.Encode(f, img)
+}

main.go

@@ -32,6 +32,8 @@ func main() {
 	cands := flag.Int("cands", 16, "Anzahl Kandidaten (Subsample)")
 	seed := flag.Int64("seed", 0, "RNG-Seed (0 = default)")
 	dotOut := flag.String("dot", "", "DOT-Export-Datei (optional)")
+	treePNG := flag.String("treepng", "", "Graphviz-Baum als PNG (optional, benötigt -dot)")
+	overlay := flag.String("overlay", "", "Map-Overlay als PNG (optional)")
 
 	flag.Parse()
 
@@ -197,8 +199,22 @@ func main() {
 			if err := viz.EmitDOT(root, *dotOut); err != nil {
 				log.Fatalf("write DOT: %v", err)
 			}
-			fmt.Printf("DOT export geschrieben: %s (mit 'dot -Tpng %s -o tree.png' rendern)\n",
+			fmt.Printf("DOT export geschrieben: %s\n", *dotOut)
-				*dotOut, *dotOut)
+
+			if *treePNG != "" {
+				if err := viz.RunGraphviz(*dotOut, *treePNG); err != nil {
+					log.Printf("Graphviz fehlgeschlagen: %v", err)
+				} else {
+					fmt.Printf("Graphviz PNG gebaut: %s\n", *treePNG)
+				}
+			}
+		}
+
+		if *overlay != "" {
+			if err := viz.RenderPNG(m, root, *overlay); err != nil {
+				log.Fatalf("write overlay PNG: %v", err)
+			}
+			fmt.Printf("Overlay PNG geschrieben: %s\n", *overlay)
 		}
 		return
 	}