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right/left handed LookAt functions

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bloeys
2022-10-01 00:12:13 +04:00
parent 051f91288d
commit 69f724922d
2 changed files with 25 additions and 3 deletions
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26
gglm/transform.go
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@ -145,7 +145,29 @@ func NewRotMat(q *Quat) *TrMat {
} }
} }
func LookAt(pos, targetPos, worldUp *Vec3) *TrMat { // LookAtRH does a right-handed coordinate system lookAt (RH is the default for OpenGL).
// Can be used to create the view matrix
func LookAtRH(pos, targetPos, worldUp *Vec3) *TrMat {
forward := SubVec3(targetPos, pos).Normalize()
right := Cross(forward, worldUp).Normalize()
up := Cross(right, forward)
return &TrMat{
Mat4: Mat4{
Data: [4][4]float32{
{right.Data[0], up.Data[0], -forward.Data[0], 0},
{right.Data[1], up.Data[1], -forward.Data[1], 0},
{right.Data[2], up.Data[2], -forward.Data[2], 0},
{-DotVec3(pos, right), -DotVec3(pos, up), DotVec3(pos, forward), 1},
},
},
}
}
// LookAtLH does a left-handed coordinate system lookAt.
// Can be used to create the view matrix
func LookAtLH(pos, targetPos, worldUp *Vec3) *TrMat {
forward := SubVec3(targetPos, pos).Normalize() forward := SubVec3(targetPos, pos).Normalize()
right := Cross(worldUp, forward).Normalize() right := Cross(worldUp, forward).Normalize()
@ -157,7 +179,7 @@ func LookAt(pos, targetPos, worldUp *Vec3) *TrMat {
{right.Data[0], up.Data[0], forward.Data[0], 0}, {right.Data[0], up.Data[0], forward.Data[0], 0},
{right.Data[1], up.Data[1], forward.Data[1], 0}, {right.Data[1], up.Data[1], forward.Data[1], 0},
{right.Data[2], up.Data[2], forward.Data[2], 0}, {right.Data[2], up.Data[2], forward.Data[2], 0},
{-DotVec3(pos, right), -DotVec3(pos, up), DotVec3(pos, forward), 1}, {-DotVec3(pos, right), -DotVec3(pos, up), -DotVec3(pos, forward), 1},
}, },
}, },
} }

2
main.go
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@ -180,7 +180,7 @@ func main() {
camPos := gglm.NewVec3(0, 0, 3) camPos := gglm.NewVec3(0, 0, 3)
worldUp := gglm.NewVec3(0, 1, 0) worldUp := gglm.NewVec3(0, 1, 0)
targetPos := gglm.NewVec3(0, 0, 0) targetPos := gglm.NewVec3(0, 0, 0)
viewMat := gglm.LookAt(camPos, targetPos, worldUp) viewMat := gglm.LookAtRH(camPos, targetPos, worldUp)
println(viewMat.String()) println(viewMat.String())
//Mat2Col //Mat2Col