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affine: Stop using multiple-dimension array for consistency

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This commit is contained in:
Hajime Hoshi 2016-11-01 23:31:10 +09:00
parent edf336499c
commit b188a0dd99
1 changed files with 22 additions and 21 deletions
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43
internal/affine/geom.go
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@ -26,7 +26,7 @@ const GeoMDim = 3
// The initial value is identity.
type GeoM struct {
initialized bool
es [GeoMDim - 1][GeoMDim]float64
es [(GeoMDim - 1) * GeoMDim]float64
}
func (g *GeoM) dim() int {
@ -35,8 +35,9 @@ func (g *GeoM) dim() int {
func (g *GeoM) initialize() {
g.initialized = true
g.es[0][0] = 1
g.es[1][1] = 1
for i := 0; i < GeoMDim-1; i++ {
g.es[i*GeoMDim+i] = 1
}
}
// Element returns a value of a matrix at (i, j).
@ -47,7 +48,7 @@ func (g *GeoM) Element(i, j int) float64 {
}
return 0
}
return g.es[i][j]
return g.es[i*GeoMDim+j]
}
// Concat multiplies a geometry matrix with the other geometry matrix.
@ -77,8 +78,8 @@ func (g *GeoM) Scale(x, y float64) {
g.initialize()
}
for i := 0; i < GeoMDim; i++ {
g.es[0][i] *= x
g.es[1][i] *= y
g.es[i] *= x
g.es[GeoMDim+i] *= y
}
}
@ -87,8 +88,8 @@ func (g *GeoM) Translate(tx, ty float64) {
if !g.initialized {
g.initialize()
}
g.es[0][2] += tx
g.es[1][2] += ty
g.es[2] += tx
g.es[GeoMDim+2] += ty
}
// Rotate rotates the matrix by theta.
@ -96,9 +97,9 @@ func (g *GeoM) Rotate(theta float64) {
sin, cos := math.Sincos(theta)
g.Concat(GeoM{
initialized: true,
es: [2][3]float64{
{cos, -sin, 0},
{sin, cos, 0},
es: [...]float64{
cos, -sin, 0,
sin, cos, 0,
},
})
}
@ -108,16 +109,16 @@ func (g *GeoM) SetElement(i, j int, element float64) {
if !g.initialized {
g.initialize()
}
g.es[i][j] = element
g.es[i*GeoMDim+j] = element
}
// ScaleGeo is deprecated as of 1.2.0-alpha. Use Scale instead.
func ScaleGeo(x, y float64) GeoM {
return GeoM{
initialized: true,
es: [2][3]float64{
{x, 0, 0},
{0, y, 0},
es: [...]float64{
x, 0, 0,
0, y, 0,
},
}
}
@ -126,9 +127,9 @@ func ScaleGeo(x, y float64) GeoM {
func TranslateGeo(tx, ty float64) GeoM {
return GeoM{
initialized: true,
es: [2][3]float64{
{1, 0, tx},
{0, 1, ty},
es: [...]float64{
1, 0, tx,
0, 1, ty,
},
}
}
@ -138,9 +139,9 @@ func RotateGeo(theta float64) GeoM {
sin, cos := math.Sincos(theta)
return GeoM{
initialized: true,
es: [2][3]float64{
{cos, -sin, 0},
{sin, cos, 0},
es: [...]float64{
cos, -sin, 0,
sin, cos, 0,
},
}
}