crunchy-rocks/draw2d
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resolve bug on transformation matrix

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This commit is contained in:
Laurent Le Goff 2011-04-14 15:01:10 +02:00
parent 9ae0038d00
commit d84ea36159
1 changed files with 14 additions and 17 deletions
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31
draw2d/transform.go
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@ -144,33 +144,30 @@ func (tr1 MatrixTransform) Multiply(tr2 MatrixTransform) MatrixTransform {
func (tr *MatrixTransform) Scale(sx, sy float64) *MatrixTransform {
tr[0] = tr[0] * sx
tr[1] = tr[1] * sx
tr[4] = tr[4] * sx
tr[2] = tr[2] * sy
tr[3] = tr[3] * sy
tr[5] = tr[5] * sy
tr[0] = sx*tr[0]
tr[1] = sx*tr[1]
tr[2] = sy*tr[2]
tr[3] = sy*tr[3]
return tr
}
func (tr *MatrixTransform) Translate(tx, ty float64) *MatrixTransform {
tr[4] = tr[4] + tx
tr[5] = tr[5] + ty
tr[4] = tx*tr[0] + ty*tr[2] + tr[4]
tr[5] = ty*tr[3] + tx*tr[1] + tr[5]
return tr
}
func (tr *MatrixTransform) Rotate(angle float64) *MatrixTransform {
ca := math.Cos(angle)
sa := math.Sin(angle)
t0 := tr[0]*ca - tr[1]*sa
t2 := tr[1]*ca - tr[3]*sa
t4 := tr[4]*ca - tr[5]*sa
tr[1] = tr[0]*sa + tr[1]*ca
tr[3] = tr[2]*sa + tr[3]*ca
tr[5] = tr[4]*sa + tr[5]*ca
c := math.Cos(angle)
s := math.Sin(angle)
t0 := c*tr[0] + s*tr[2]
t1 := s*tr[3] + c*tr[1]
t2 := c*tr[2] - s*tr[0]
t3 := c*tr[3] - s*tr[1]
tr[0] = t0
tr[1] = t1
tr[2] = t2
tr[4] = t4
tr[3] = t3
return tr
}