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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. // The initial value is identity.
type GeoM struct { type GeoM struct {
initialized bool initialized bool
es [GeoMDim - 1][GeoMDim]float64 es [(GeoMDim - 1) * GeoMDim]float64
} }
func (g *GeoM) dim() int { func (g *GeoM) dim() int {
@ -35,8 +35,9 @@ func (g *GeoM) dim() int {
func (g *GeoM) initialize() { func (g *GeoM) initialize() {
g.initialized = true g.initialized = true
g.es[0][0] = 1 for i := 0; i < GeoMDim-1; i++ {
g.es[1][1] = 1 g.es[i*GeoMDim+i] = 1
}
} }
// Element returns a value of a matrix at (i, j). // 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 0
} }
return g.es[i][j] return g.es[i*GeoMDim+j]
} }
// Concat multiplies a geometry matrix with the other geometry matrix. // Concat multiplies a geometry matrix with the other geometry matrix.
@ -77,8 +78,8 @@ func (g *GeoM) Scale(x, y float64) {
g.initialize() g.initialize()
} }
for i := 0; i < GeoMDim; i++ { for i := 0; i < GeoMDim; i++ {
g.es[0][i] *= x g.es[i] *= x
g.es[1][i] *= y g.es[GeoMDim+i] *= y
} }
} }
@ -87,8 +88,8 @@ func (g *GeoM) Translate(tx, ty float64) {
if !g.initialized { if !g.initialized {
g.initialize() g.initialize()
} }
g.es[0][2] += tx g.es[2] += tx
g.es[1][2] += ty g.es[GeoMDim+2] += ty
} }
// Rotate rotates the matrix by theta. // Rotate rotates the matrix by theta.
@ -96,9 +97,9 @@ func (g *GeoM) Rotate(theta float64) {
sin, cos := math.Sincos(theta) sin, cos := math.Sincos(theta)
g.Concat(GeoM{ g.Concat(GeoM{
initialized: true, initialized: true,
es: [2][3]float64{ es: [...]float64{
{cos, -sin, 0}, cos, -sin, 0,
{sin, cos, 0}, sin, cos, 0,
}, },
}) })
} }
@ -108,16 +109,16 @@ func (g *GeoM) SetElement(i, j int, element float64) {
if !g.initialized { if !g.initialized {
g.initialize() 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. // ScaleGeo is deprecated as of 1.2.0-alpha. Use Scale instead.
func ScaleGeo(x, y float64) GeoM { func ScaleGeo(x, y float64) GeoM {
return GeoM{ return GeoM{
initialized: true, initialized: true,
es: [2][3]float64{ es: [...]float64{
{x, 0, 0}, x, 0, 0,
{0, y, 0}, 0, y, 0,
}, },
} }
} }
@ -126,9 +127,9 @@ func ScaleGeo(x, y float64) GeoM {
func TranslateGeo(tx, ty float64) GeoM { func TranslateGeo(tx, ty float64) GeoM {
return GeoM{ return GeoM{
initialized: true, initialized: true,
es: [2][3]float64{ es: [...]float64{
{1, 0, tx}, 1, 0, tx,
{0, 1, ty}, 0, 1, ty,
}, },
} }
} }
@ -138,9 +139,9 @@ func RotateGeo(theta float64) GeoM {
sin, cos := math.Sincos(theta) sin, cos := math.Sincos(theta)
return GeoM{ return GeoM{
initialized: true, initialized: true,
es: [2][3]float64{ es: [...]float64{
{cos, -sin, 0}, cos, -sin, 0,
{sin, cos, 0}, sin, cos, 0,
}, },
} }
} }