67 lines
1.4 KiB
Go
67 lines
1.4 KiB
Go
package main
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const EPS = 0.001
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type SDF interface {
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Distance(Vector3) float64
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}
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func Gradient(sdf SDF, p Vector3, eps float64) Vector3 {
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dx := (sdf.Distance(p.Add(Vector3{X: eps})) - sdf.Distance(p.Add(Vector3{X: -eps}))) / (2 * eps)
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dy := (sdf.Distance(p.Add(Vector3{Y: eps})) - sdf.Distance(p.Add(Vector3{Y: -eps}))) / (2 * eps)
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dz := (sdf.Distance(p.Add(Vector3{Z: eps})) - sdf.Distance(p.Add(Vector3{Z: -eps}))) / (2 * eps)
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return Vector3{X: dx, Y: dy, Z: dz}
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}
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// Some transformations see https://iquilezles.org/articles/distfunctions/
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type translatedSDF struct {
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primitive SDF
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translate Vector3
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}
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func (s translatedSDF) Distance(p Vector3) float64 {
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return s.primitive.Distance(p.Sub(s.translate))
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}
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type rotatedSDF struct {
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primitive SDF
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rotVector Vector3
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angle float64
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}
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func (s rotatedSDF) Distance(p Vector3) float64 {
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rotated_p := rotate(p, s.rotVector, s.angle)
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return s.primitive.Distance(rotated_p)
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}
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type scaledSDF struct {
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primitive SDF
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scale float64
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}
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func (s scaledSDF) Distance(p Vector3) float64 {
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return s.primitive.Distance(p.Scale(1/s.scale)) * s.scale
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}
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type infiniteRep struct {
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primitive SDF
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cellSize Vector3
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}
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// TODO
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// func (s infiniteRep) Distance(p Vector3) float64 {
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// x, y, z := p.Unpack()
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// sx, sy, sz := s.cellSize.Unpack()
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// }
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// Sphere
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type Sphere struct {
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center Vector3
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radius float64
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}
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func (s Sphere) Distance(p Vector3) float64 {
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return p.Sub(s.center).Length()
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}
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