fix Union CPU implementations for more than 2 unions

cpu_evaluators.go

@@ -120,26 +120,18 @@ func (u *OpUnion) Evaluate(pos []ms3.Vec, dist []float32, userData any) error {
 	}
 	auxDist := vp.Float.Acquire(len(dist))
 	defer vp.Float.Release(auxDist)
-	// This algorithm of switching distance buffers avoids needing to allocate
-	// a new distance buffer for every SDF in the union list.
-	distCalc, distAccum := dist, auxDist
-	if len(u.joined)%2 != 0 {
-		// If odd number of elements we ensure the last accumulated
-		// distance calculation is stored in dist to avoid needing to copy.
-		// All we need to do is switch our buffers once before we start.
-		distCalc, distAccum = distAccum, distCalc
-	}
-	for i := range u.joined {
-		err = evaluateSDF3(u.joined[i], pos, distCalc, userData)
+	err = evaluateSDF3(u.joined[0], pos, dist, userData)
+	if err != nil {
+		return err
+	}
+	for _, shape := range u.joined[1:] {
+		err = evaluateSDF3(shape, pos, auxDist, userData)
 		if err != nil {
 			return err
 		}
-		for i, d := range distAccum {
-			distAccum[i] = math32.Min(d, distCalc[i])
+		for i, d := range dist {
+			dist[i] = math32.Min(d, auxDist[i])
 		}
-		// Buffer switcheroo for next evaluation to not overwrite
-		// the minumum distance we just calculated.
-		distCalc, distAccum = distAccum, distCalc
 	}
 	return nil
 }
@@ -553,11 +545,11 @@ func (l *line2D) Evaluate(pos []ms2.Vec, dist []float32, userData any) error {
 	a := l.a
 	ba := ms2.Sub(l.b, l.a)
 	dotba := ms2.Dot(ba, ba)
-	t := l.thick / 2
+	w := l.width / 2
 	for i, p := range pos {
 		pa := ms2.Sub(p, a)
 		h := ms1.Clamp(ms2.Dot(pa, ba)/dotba, 0, 1)
-		dist[i] = ms2.Norm(ms2.Sub(pa, ms2.Scale(h, ba))) - t
+		dist[i] = ms2.Norm(ms2.Sub(pa, ms2.Scale(h, ba))) - w
 	}
 	return nil
 }
@@ -705,19 +697,19 @@ func (u *OpUnion2D) Evaluate(pos []ms2.Vec, dist []float32, userData any) error
 	}
 	auxDist := vp.Float.Acquire(len(dist))
 	defer vp.Float.Release(auxDist)
-	distCalc, distAccum := dist, auxDist
-	if len(u.joined)%2 != 0 {
-		distCalc, distAccum = distAccum, distCalc
+
+	err = evaluateSDF2(u.joined[0], pos, dist, userData)
+	if err != nil {
+		return err
 	}
-	for i := range u.joined {
-		err = evaluateSDF2(u.joined[i], pos, distCalc, userData)
+	for _, shape := range u.joined[1:] {
+		err = evaluateSDF2(shape, pos, auxDist, userData)
 		if err != nil {
 			return err
 		}
-		for i, d := range distAccum {
-			distAccum[i] = math32.Min(d, distCalc[i])
+		for i, d := range dist {
+			dist[i] = math32.Min(d, auxDist[i])
 		}
-		distCalc, distAccum = distAccum, distCalc
 	}
 	return nil
 }

examples/bolt/main.go

@@ -57,7 +57,7 @@ func run() error {
 	}
 	defer fpvis.Close()
 
-	err = gsdfaux.Render(sdf, gsdfaux.RenderConfig{
+	err = gsdfaux.RenderShader3D(sdf, gsdfaux.RenderConfig{
 		STLOutput:    fpstl,
 		VisualOutput: fpvis,
 		Resolution:   sdf.Bounds().Diagonal() / 200,

examples/fibonacci-showerhead/main.go

@@ -100,7 +100,7 @@ func run() error {
 	}
 	defer fpvis.Close()
 
-	err = gsdfaux.Render(object, gsdfaux.RenderConfig{
+	err = gsdfaux.RenderShader3D(object, gsdfaux.RenderConfig{
 		STLOutput:     fpstl,
 		VisualOutput:  fpvis,
 		Resolution:    object.Bounds().Diagonal() / 200,

examples/gasket/main.go

@@ -12,6 +12,7 @@ import (
 	"github.com/soypat/glgl/math/ms2"
 	"github.com/soypat/gsdf"
 	"github.com/soypat/gsdf/glbuild"
+	"github.com/soypat/gsdf/gleval"
 	"github.com/soypat/gsdf/gsdfaux"
 )
 
@@ -72,7 +73,11 @@ func scene() (glbuild.Shader3D, error) {
 	poly2 = gsdf.Offset2D(poly2, tol)
 	if visualization2D != "" {
 		start := time.Now()
-		err = gsdfaux.RenderPNGFile(visualization2D, poly2, 500, false, nil)
+		sdf, err := gleval.NewCPUSDF2(poly2)
+		if err != nil {
+			return nil, err
+		}
+		err = gsdfaux.RenderPNGFile(visualization2D, sdf, 500, nil)
 		if err != nil {
 			return nil, err
 		}
@@ -99,7 +104,7 @@ func run() error {
 	}
 	defer fpvis.Close()
 
-	err = gsdfaux.Render(object, gsdfaux.RenderConfig{
+	err = gsdfaux.RenderShader3D(object, gsdfaux.RenderConfig{
 		STLOutput:    fpstl,
 		VisualOutput: fpvis,
 		Resolution:   object.Bounds().Diagonal() / 350,

examples/image/image.go

@@ -7,11 +7,12 @@ import (
 	"github.com/soypat/glgl/math/ms2"
 	"github.com/soypat/gsdf"
 	"github.com/soypat/gsdf/glbuild"
+	"github.com/soypat/gsdf/gleval"
 	"github.com/soypat/gsdf/gsdfaux"
 )
 
 const dim = 20
-const filename = "circle.png"
+const filename = "image-example.png"
 
 func scene() (glbuild.Shader2D, error) {
 	s, err := gsdf.NewCircle(dim)
@@ -36,9 +37,18 @@ func main() {
 	if err != nil {
 		log.Fatal(err)
 	}
-	err = gsdfaux.RenderPNGFile(filename, s, 1080, useGPU, nil)
+	var sdf2 gleval.SDF2
+	if useGPU {
+		sdf2, err = gsdfaux.MakeGPUSDF2(s)
+	} else {
+		sdf2, err = gleval.NewCPUSDF2(s)
+	}
+	if err != nil {
+		log.Fatal(err)
+	}
+	err = gsdfaux.RenderPNGFile(filename, sdf2, 1080, nil)
 	if err != nil {
 		log.Fatal(err)
 	}
-	fmt.Println("PNG file rendered")
+	fmt.Println("PNG file rendered to", filename)
 }

examples/npt-flange/flange.go

@@ -77,7 +77,7 @@ func run() error {
 	}
 	defer fpvis.Close()
 
-	err = gsdfaux.Render(s, gsdfaux.RenderConfig{
+	err = gsdfaux.RenderShader3D(s, gsdfaux.RenderConfig{
 		STLOutput:    fpstl,
 		VisualOutput: fpvis,
 		Resolution:   s.Bounds().Diagonal() / 200,

examples/plantpot/main.go

@@ -13,6 +13,7 @@ import (
 	"github.com/soypat/glgl/math/ms2"
 	"github.com/soypat/gsdf"
 	"github.com/soypat/gsdf/glbuild"
+	"github.com/soypat/gsdf/gleval"
 	"github.com/soypat/gsdf/gsdfaux"
 )
 
@@ -54,7 +55,11 @@ func scenePotBase() (glbuild.Shader3D, error) {
 	if err != nil {
 		return nil, err
 	}
-	err = gsdfaux.RenderPNGFile(visualization2D, poly2, 1080, false, gsdfaux.ColorConversionInigoQuilez(poly2.Bounds().Diagonal()/3))
+	sdf, err := gleval.NewCPUSDF2(poly2)
+	if err != nil {
+		return nil, err
+	}
+	err = gsdfaux.RenderPNGFile(visualization2D, sdf, 1080, nil)
 	if err != nil {
 		return nil, err
 	}
@@ -79,7 +84,7 @@ func run() error {
 	}
 	defer fpvis.Close()
 
-	err = gsdfaux.Render(object, gsdfaux.RenderConfig{
+	err = gsdfaux.RenderShader3D(object, gsdfaux.RenderConfig{
 		STLOutput:    fpstl,
 		VisualOutput: fpvis,
 		Resolution:   object.Bounds().Diagonal() / 350,