Quaternion rotations worked
parent
d624077dd1
commit
8fb02993f4
10
main.go
10
main.go
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@ -94,7 +94,7 @@ func run() {
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}
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gl.UseProgram(program)
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projection := mgl32.Perspective(mgl32.DegToRad(45.0), float32(width)/float32(height), 0.1, 10.0)
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projection := mgl32.Perspective(mgl32.DegToRad(45.0), float32(width)/float32(height), 0.01, 1000.0)
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projectionUniform := gl.GetUniformLocation(program, gl.Str("projection\x00"))
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gl.UniformMatrix4fv(projectionUniform, 1, false, &projection[0])
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@ -219,7 +219,7 @@ func handleEvents(running bool, window *sdl.Window, camera *gl_objects.Camera) b
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}
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if t.Keysym.Sym == sdl.K_w {
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if t.Type == sdl.KEYDOWN {
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camera.SetZVelocity(-1)
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camera.SetZVelocity(1)
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} else if t.Type == sdl.KEYUP {
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camera.SetZVelocity(0)
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}
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@ -233,7 +233,7 @@ func handleEvents(running bool, window *sdl.Window, camera *gl_objects.Camera) b
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}
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if t.Keysym.Sym == sdl.K_s {
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if t.Type == sdl.KEYDOWN {
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camera.SetZVelocity(1)
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camera.SetZVelocity(-1)
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} else if t.Type == sdl.KEYUP {
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camera.SetZVelocity(0)
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} }
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@ -260,14 +260,14 @@ func handleEvents(running bool, window *sdl.Window, camera *gl_objects.Camera) b
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}
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if t.Keysym.Sym == sdl.K_z {
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if t.Type == sdl.KEYDOWN {
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camera.SetRotationVelocity(1)
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camera.SetRotationVelocity(-1)
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} else if t.Type == sdl.KEYUP {
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camera.SetRotationVelocity(0)
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}
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}
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if t.Keysym.Sym == sdl.K_x {
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if t.Type == sdl.KEYDOWN {
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camera.SetRotationVelocity(-1)
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camera.SetRotationVelocity(1)
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} else if t.Type == sdl.KEYUP {
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camera.SetRotationVelocity(0)
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}
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@ -5,29 +5,37 @@ import (
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gl "github.com/go-gl/gl/v3.1/gles2"
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"github.com/go-gl/mathgl/mgl32"
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"gitea.wisellama.rocks/carpy-breakout/pkg/math_helpers"
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)
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var OriginalDirection mgl32.Vec3 = mgl32.Vec3{0, 0, -1}
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/*
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Positive X = right
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Positive Y = up
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Positive Z = backward (outward, towards you)
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Negative Z = forwards (inward)
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*/
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type Camera struct {
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Position mgl32.Vec3
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Direction mgl32.Vec3
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OriginalDirection mgl32.Vec3
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Up mgl32.Vec3
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OriginalUp mgl32.Vec3
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Velocity mgl32.Vec3
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Movestep float32
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MoveStep float32
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RotationVelocity float32
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Rotation mgl32.Vec3
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RotateStep float32
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MouseSensitivity float32
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}
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func NewCamera() (Camera) {
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camera := Camera{}
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camera.Up = mgl32.Vec3{0, 1, 0}
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camera.Direction = OriginalDirection
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camera.Movestep = 0.1
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camera.RotateStep = 0.05
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camera.OriginalUp = mgl32.Vec3{0, 1, 0}
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camera.Direction = mgl32.Vec3{0, 0, -1}
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camera.OriginalDirection = mgl32.Vec3{0, 0, -1}
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camera.MoveStep = 0.1
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camera.RotateStep = 0.02
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camera.MouseSensitivity = 0.01
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return camera
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}
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@ -43,42 +51,60 @@ func (c *Camera) Draw(program uint32) {
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func (c *Camera) Update() {
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c.Rotate(0, 0)
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c.Move(c.Velocity.Mul(c.Movestep))
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c.Move(c.Velocity)
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}
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func (c *Camera) Rotate(mouseX, mouseY int32) {
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// X mouse movement = rotation about the Y axis
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// Y mouse movement = rotation about the X axis
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angle := mgl32.Vec3{}
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// X Rotation (pitch) - mouse up/down
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c.Rotation[0] = c.RotateStep * -1 * float32(mouseY) * .01
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xRotate := mgl32.HomogRotate3DX(c.Rotation[0])
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c.Up = mgl32.TransformNormal(c.Up, xRotate).Normalize()
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c.Direction = mgl32.TransformNormal(c.Direction, xRotate).Normalize()
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angle[0] = -1 * float32(mouseY) * c.MouseSensitivity
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// Y Rotation (yaw) - mouse left/right
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c.Rotation[1] = c.RotateStep * -1 * float32(mouseX) * .01
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yRotate := mgl32.HomogRotate3DY(c.Rotation[1])
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c.Up = mgl32.TransformNormal(c.Up, yRotate).Normalize()
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c.Direction = mgl32.TransformNormal(c.Direction, yRotate).Normalize()
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angle[1] = -1 * float32(mouseX) * c.MouseSensitivity
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// Z Rotation (roll) - keyboard z/x
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c.Rotation[2] = c.RotateStep * c.RotationVelocity
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zRotate := mgl32.HomogRotate3DZ(c.Rotation[2])
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c.Up = mgl32.TransformNormal(c.Up, zRotate).Normalize()
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c.Direction = mgl32.TransformNormal(c.Direction, zRotate).Normalize()
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angle[2] = c.RotationVelocity
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if angle.LenSqr() == 0 {
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return
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}
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angle = angle.Mul(c.RotateStep)
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relativeY := c.Up
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relativeZ := c.Direction
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relativeX := relativeZ.Cross(relativeY)
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quatX := mgl32.QuatRotate(angle.X(), relativeX)
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c.Up = quatX.Rotate(c.Up)
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c.Direction = quatX.Rotate(c.Direction)
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quatY := mgl32.QuatRotate(angle.Y(), relativeY)
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c.Up = quatY.Rotate(c.Up)
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c.Direction = quatY.Rotate(c.Direction)
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quatZ := mgl32.QuatRotate(angle.Z(), relativeZ)
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c.Up = quatZ.Rotate(c.Up)
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c.Direction = quatZ.Rotate(c.Direction)
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}
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func (c *Camera) Move(vec mgl32.Vec3) {
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// Rotate our movement vector to apply in our current direction
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rotation := math_helpers.RotationMatrix(vec, c.Direction)
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t := mgl32.TransformCoordinate(vec, rotation)
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log.Println(vec)
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log.Println(t)
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if vec.LenSqr() == 0 {
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return
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}
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// Then translate
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translation := mgl32.Translate3D(t.X(), t.Y(), t.Z())
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c.Position = mgl32.TransformCoordinate(c.Position, translation)
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vec = vec.Normalize()
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vec = vec.Mul(c.MoveStep)
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perp := c.Direction.Cross(c.Up)
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relativeY := c.Up.Mul(vec.Y())
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relativeZ := c.Direction.Mul(vec.Z())
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relativeX := perp.Mul(vec.X())
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relativeMove := mgl32.Vec3{}
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relativeMove = relativeMove.Add(relativeX)
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relativeMove = relativeMove.Add(relativeY)
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relativeMove = relativeMove.Add(relativeZ)
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log.Printf("relativeMove = %v, vec = %v", relativeMove.Len(), vec.Len())
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c.Position = c.Position.Add(relativeMove)
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}
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func (c *Camera) SetXVelocity(v float32) {
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@ -0,0 +1,51 @@
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# How to rotate using Quaternions
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https://math.stackexchange.com/a/535223
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To answer the question simply, given:
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```
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P = [0, p1, p2, p3] <-- point vector
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R = [w, x, y, z] <-- rotation
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R' = [w, -x, -y, -z]
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```
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For the example in the question, these are:
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```
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P = [0, 1, 0, 0]
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R = [0.707, 0.0, 0.707, 0.0]
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R' = [0.707, 0.0, -0.707, 0.0]
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```
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You can calculate the resulting vector using the Hamilton product H(a, b) by:
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```
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P' = RPR'
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P' = H(H(R, P), R')
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```
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Performing the calculations:
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```
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H(R, P) = [0.0, 0.707, 0.0, -0.707]
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P' = H(H(R, P), R') = [0.0, 0.0, 0.0, -1.0 ]
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```
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Thus, the example above illustrates a rotation of 90 degrees about the
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y-axis for the point (1, 0, 0). The result is (0, 0, -1). (Note that
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the first element of P' will always be 0 and can therefore be
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discarded.)
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For those unfamiliar with quaternions, it's worth noting that the
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quaternion R may be determined using the formula:
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```
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a = angle to rotate
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[x, y, z] = axis to rotate around (unit vector)
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R = [cos(a/2), sin(a/2)*x, sin(a/2)*y, sin(a/2)*z]
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```
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See here for further reference.
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http://en.wikipedia.org/wiki/Quaternions_and_spatial_rotation
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@ -1,15 +0,0 @@
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package math_helpers
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import (
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"github.com/go-gl/mathgl/mgl32"
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)
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func RotationMatrix(a, b mgl32.Vec3) mgl32.Mat4 {
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axis := a.Cross(b)
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angle := a.Dot(b)
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if angle == 0 || axis.LenSqr() == 0 {
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return mgl32.Ident4()
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} else {
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return mgl32.HomogRotate3D(angle, axis)
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}
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}
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