108 lines
2.1 KiB
Go
108 lines
2.1 KiB
Go
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package shape
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import (
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"zworld/plugins/math/mat4"
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"zworld/plugins/math/vec3"
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)
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type Plane struct {
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Normal vec3.T
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Distance float32
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}
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func (p *Plane) normalize() {
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length := p.Normal.LengthSqr() + p.Distance*p.Distance
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p.Normal = p.Normal.Scaled(1 / length)
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p.Distance /= length
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}
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func (p *Plane) DistanceToPoint(point vec3.T) float32 {
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return vec3.Dot(p.Normal, point) + p.Distance
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}
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type Frustum struct {
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Front, Back, Left, Right, Top, Bottom Plane
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}
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func (f *Frustum) IntersectsSphere(s *Sphere) bool {
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if f.Left.DistanceToPoint(s.Center) <= -s.Radius {
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return false
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}
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if f.Right.DistanceToPoint(s.Center) <= -s.Radius {
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return false
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}
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if f.Top.DistanceToPoint(s.Center) <= -s.Radius {
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return false
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}
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if f.Bottom.DistanceToPoint(s.Center) <= -s.Radius {
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return false
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}
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if f.Front.DistanceToPoint(s.Center) <= -s.Radius {
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return false
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}
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if f.Back.DistanceToPoint(s.Center) <= -s.Radius {
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return false
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}
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return true
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}
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func FrustumFromMatrix(vp mat4.T) Frustum {
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f := Frustum{
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Left: Plane{
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Normal: vec3.T{
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X: vp[0+3] + vp[0+0],
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Y: vp[4+3] + vp[4+0],
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Z: vp[8+3] + vp[8+0],
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},
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Distance: vp[12+3] + vp[12+0],
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},
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Right: Plane{
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Normal: vec3.T{
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X: vp[0+3] - vp[0+0],
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Y: vp[4+3] - vp[4+0],
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Z: vp[8+3] - vp[8+0],
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},
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Distance: vp[12+3] - vp[12+0],
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},
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Top: Plane{
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Normal: vec3.T{
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X: vp[0+3] - vp[0+1],
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Y: vp[4+3] - vp[4+1],
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Z: vp[8+3] - vp[8+1],
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},
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Distance: vp[12+3] - vp[12+1],
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},
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Bottom: Plane{
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Normal: vec3.T{
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X: vp[0+3] + vp[0+1],
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Y: vp[4+3] + vp[4+1],
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Z: vp[8+3] + vp[8+1],
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},
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Distance: vp[12+3] + vp[12+1],
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},
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Back: Plane{
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Normal: vec3.T{
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X: vp[0+3] + vp[0+2],
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Y: vp[4+3] + vp[4+2],
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Z: vp[8+3] + vp[8+2],
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},
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Distance: vp[12+3] + vp[12+2],
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},
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Front: Plane{
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Normal: vec3.T{
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X: vp[0+3] - vp[0+2],
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Y: vp[4+3] - vp[4+2],
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Z: vp[8+3] - vp[8+2],
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},
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Distance: vp[12+3] - vp[12+2],
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},
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}
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f.Front.normalize()
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f.Back.normalize()
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f.Top.normalize()
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f.Bottom.normalize()
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f.Left.normalize()
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f.Right.normalize()
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return f
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}
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