示例#1
0
// Vec3Diff returns the rotation quaternion between two vectors.
func Vec3Diff(a, b *vec3.T) T {
	cr := vec3.Cross(a, b)
	sr := math.Sqrt(2 * (1 + vec3.Dot(a, b)))
	oosr := 1 / sr

	q := T{cr[0] * oosr, cr[1] * oosr, cr[2] * oosr, sr * 0.5}
	return q.Normalized()
}
示例#2
0
func (c *FreeFlightCamera) Lift(dist float32) {
	position := vec3.T(c.Pos)
	forward := vec3.T(c.Forward())
	right := vec3.T(c.Right())
	up := vec3.Cross(&forward, &right)

	up.Scale(dist)
	c.Pos = Vec3(vec3.Add(&position, &up))
}
示例#3
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func (rt *Raytracer) calcIncVectors(camera Camera, size image.Point) (vec3.T, vec3.T, vec3.T) {
	width := float32(size.X)
	height := float32(size.Y)

	lookAtPoint := vec3.T(camera.LookAt())
	eyePoint := vec3.T(camera.Position())
	up := vec3.T(camera.Up())

	viewDirection := vec3.Sub(&lookAtPoint, &eyePoint)
	u := vec3.Cross(&viewDirection, &up)
	v := vec3.Cross(&u, &viewDirection)
	u.Normalize()
	v.Normalize()

	viewPlaneHalfWidth := float32(math.Tan(float64(rt.cfg.FieldOfView / 2)))
	aspectRatio := height / width
	viewPlaneHalfHeight := aspectRatio * viewPlaneHalfWidth

	sV := v.Scaled(viewPlaneHalfHeight)
	sU := u.Scaled(viewPlaneHalfWidth)

	lookV := vec3.Sub(&lookAtPoint, &sV)
	viewPlaneBottomLeftPoint := vec3.Sub(&lookV, &sU)

	xIncVector := u.Scaled(2 * viewPlaneHalfWidth)
	yIncVector := v.Scaled(2 * viewPlaneHalfHeight)

	xIncVector[0] /= width
	xIncVector[1] /= width
	xIncVector[2] /= width

	yIncVector[0] /= height
	yIncVector[1] /= height
	yIncVector[2] /= height

	return xIncVector, yIncVector, viewPlaneBottomLeftPoint
}
示例#4
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func (c *FreeFlightCamera) Right() Vec3 {
	up := vec3.T(c.Up())
	forward := vec3.T(c.Forward())
	return Vec3(vec3.Cross(&up, &forward))
}
示例#5
0
// Cross returns the cross product of two vectors.
func Cross(a, b *T) T {
	a3 := a.Vec3DividedByW()
	b3 := b.Vec3DividedByW()
	c3 := vec3.Cross(&a3, &b3)
	return T{c3[0], c3[1], c3[2], 1}
}