graphics: Make copying GeoM faster

internal/affine/affine.go

@@ -14,27 +14,46 @@
 
 package affine
 
+import (
+	"github.com/hajimehoshi/ebiten/internal/endian"
+)
+
+var identityValues = map[int]string{
+	ColorMDim: colorMValueString([ColorMDim - 1][ColorMDim]float64{
+		{1, 0, 0, 0, 0},
+		{0, 1, 0, 0, 0},
+		{0, 0, 1, 0, 0},
+		{0, 0, 0, 1, 0},
+	}),
+	GeoMDim: geoMValueString([GeoMDim - 1][GeoMDim]float64{
+		{1, 0, 0},
+		{0, 1, 0},
+	}),
+}
+
+func uint64ToBytes(value uint64) []uint8 {
+	result := make([]uint8, 8)
+	if endian.IsLittle() {
+		for i := 0; i < 8; i++ {
+			result[i] = uint8(value)
+			value >>= 8
+		}
+	} else {
+		for i := 7; 0 <= i; i-- {
+			result[i] = uint8(value)
+			value >>= 8
+		}
+	}
+	return result
+}
+
 type affine interface {
 	dim() int
 	Element(i, j int) float64
 	SetElement(i, j int, element float64)
 }
 
-func isIdentity(ebiten affine) bool {
-	dim := ebiten.dim()
-	for i := 0; i < dim-1; i++ {
-		for j := 0; j < dim; j++ {
-			element := ebiten.Element(i, j)
-			if i == j && element != 1 {
-				return false
-			} else if i != j && element != 0 {
-				return false
-			}
-		}
-	}
-	return true
-}
-
+// add is deprecated
 func add(lhs, rhs, result affine) {
 	dim := lhs.dim()
 	if dim != rhs.dim() {

internal/affine/affine_js.go

@@ -20,27 +20,25 @@ import (
 	"github.com/gopherjs/gopherjs/js"
 )
 
-// Element returns a value of a matrix at (i, j).
-func (c *ColorM) Element(i, j int) float64 {
-	if c.values == "" {
+func element(values string, dim int, i, j int) float64 {
+	if values == "" {
 		if i == j {
 			return 1
 		}
 		return 0
 	}
-	a := js.NewArrayBuffer([]uint8(c.values))
+	a := js.NewArrayBuffer([]uint8(values))
 	af64 := js.Global.Get("Float64Array").New(a)
-	return af64.Index(i*ColorMDim + j).Float()
+	return af64.Index(i*dim + j).Float()
 }
 
-// SetElement sets an element at (i, j).
-func (c *ColorM) SetElement(i, j int, value float64) {
-	if c.values == "" {
-		c.values = colorMIdentityValue
+func setElement(values string, dim int, i, j int, value float64) string {
+	if values == "" {
+		values = identityValues[dim]
 	}
-	a := js.NewArrayBuffer([]uint8(c.values))
+	a := js.NewArrayBuffer([]uint8(values))
 	a8 := js.Global.Get("Uint8Array").New(a)
 	af64 := js.Global.Get("Float64Array").New(a)
-	af64.SetIndex(i*ColorMDim+j, value)
-	c.values = string(a8.Interface().([]uint8))
+	af64.SetIndex(i*dim+j, value)
+	return string(a8.Interface().([]uint8))
 }

internal/affine/affine_notjs.go

@@ -22,36 +22,34 @@ import (
 	"github.com/hajimehoshi/ebiten/internal/endian"
 )
 
-// Element returns a value of a matrix at (i, j).
-func (c *ColorM) Element(i, j int) float64 {
-	if c.values == "" {
+func element(values string, dim int, i, j int) float64 {
+	if values == "" {
 		if i == j {
 			return 1
 		}
 		return 0
 	}
-	offset := 8 * (i*ColorMDim + j)
+	offset := 8 * (i*dim + j)
 	v := uint64(0)
 	if endian.IsLittle() {
 		for k := 7; 0 <= k; k-- {
 			v <<= 8
-			v += uint64(c.values[offset+k])
+			v += uint64(values[offset+k])
 		}
 	} else {
 		for k := 0; k < 8; k++ {
 			v <<= 8
-			v += uint64(c.values[offset+k])
+			v += uint64(values[offset+k])
 		}
 	}
 	return math.Float64frombits(v)
 }
 
-// SetElement sets an element at (i, j).
-func (c *ColorM) SetElement(i, j int, value float64) {
-	if c.values == "" {
-		c.values = colorMIdentityValue
+func setElement(values string, dim int, i, j int, value float64) string {
+	if values == "" {
+		values = identityValues[dim]
 	}
 	b := uint64ToBytes(math.Float64bits(value))
-	offset := 8 * (i*ColorMDim + j)
-	c.values = c.values[:offset] + string(b) + c.values[offset+8:]
+	offset := 8 * (i*dim + j)
+	return values[:offset] + string(b) + values[offset+8:]
 }

internal/affine/colorm.go

@@ -16,29 +16,11 @@ package affine
 
 import (
 	"math"
-
-	"github.com/hajimehoshi/ebiten/internal/endian"
 )
 
 // ColorMDim is a dimension of a ColorM.
 const ColorMDim = 5
 
-func uint64ToBytes(value uint64) []uint8 {
-	result := make([]uint8, 8)
-	if endian.IsLittle() {
-		for i := 0; i < 8; i++ {
-			result[i] = uint8(value)
-			value >>= 8
-		}
-	} else {
-		for i := 7; 0 <= i; i-- {
-			result[i] = uint8(value)
-			value >>= 8
-		}
-	}
-	return result
-}
-
 func colorMValueString(values [ColorMDim - 1][ColorMDim]float64) string {
 	b := make([]uint8, 0, (ColorMDim-1)*(ColorMDim)*8)
 	for i := 0; i < ColorMDim-1; i++ {
@@ -49,15 +31,6 @@ func colorMValueString(values [ColorMDim - 1][ColorMDim]float64) string {
 	return string(b)
 }
 
-var (
-	colorMIdentityValue = colorMValueString([ColorMDim - 1][ColorMDim]float64{
-		{1, 0, 0, 0, 0},
-		{0, 1, 0, 0, 0},
-		{0, 0, 1, 0, 0},
-		{0, 0, 0, 1, 0},
-	})
-)
-
 // A ColorM represents a matrix to transform coloring when rendering an image.
 //
 // A ColorM is applied to the source alpha color
@@ -75,12 +48,22 @@ func (c *ColorM) dim() int {
 	return ColorMDim
 }
 
+// Element returns a value of a matrix at (i, j).
+func (c *ColorM) Element(i, j int) float64 {
+	return element(c.values, ColorMDim, i, j)
+}
+
+// SetElement sets an element at (i, j).
+func (c *ColorM) SetElement(i, j int, element float64) {
+	c.values = setElement(c.values, ColorMDim, i, j, element)
+}
+
 func (c *ColorM) Equals(other *ColorM) bool {
 	if c.values == "" {
-		c.values = colorMIdentityValue
+		c.values = identityValues[ColorMDim]
 	}
 	if other.values == "" {
-		other.values = colorMIdentityValue
+		other.values = identityValues[ColorMDim]
 	}
 	return c.values == other.values
 }
@@ -93,7 +76,7 @@ func (c *ColorM) Concat(other ColorM) {
 	*c = result
 }
 
-// Add adds a color matrix with the other color matrix.
+// Add is deprecated.
 func (c *ColorM) Add(other ColorM) {
 	result := ColorM{}
 	add(&other, c, &result)

internal/affine/geom.go

@@ -21,52 +21,48 @@ import (
 // GeoMDim is a dimension of a GeoM.
 const GeoMDim = 3
 
+func geoMValueString(values [GeoMDim - 1][GeoMDim]float64) string {
+	b := make([]uint8, 0, (GeoMDim-1)*(GeoMDim)*8)
+	for i := 0; i < GeoMDim-1; i++ {
+		for j := 0; j < GeoMDim; j++ {
+			b = append(b, uint64ToBytes(math.Float64bits(values[i][j]))...)
+		}
+	}
+	return string(b)
+}
+
 // A GeoM represents a matrix to transform geometry when rendering an image.
 //
 // The initial value is identity.
 type GeoM struct {
-	initialized bool
-	es          [(GeoMDim - 1) * GeoMDim]float64
+	// When values is empty, this matrix is identity.
+	values string
 }
 
 func (g *GeoM) dim() int {
 	return GeoMDim
 }
 
-func (g *GeoM) initialize() {
-	g.initialized = true
-	for i := 0; i < GeoMDim-1; i++ {
-		g.es[i*GeoMDim+i] = 1
-	}
-}
-
 // Element returns a value of a matrix at (i, j).
 func (g *GeoM) Element(i, j int) float64 {
-	if !g.initialized {
-		if i == j {
-			return 1
-		}
-		return 0
-	}
-	return g.es[i*GeoMDim+j]
+	return element(g.values, GeoMDim, i, j)
+}
+
+// SetElement sets an element at (i, j).
+func (g *GeoM) SetElement(i, j int, element float64) {
+	g.values = setElement(g.values, GeoMDim, i, j, element)
 }
 
 // Concat multiplies a geometry matrix with the other geometry matrix.
 // This is same as muptiplying the matrix other and the matrix g in this order.
 func (g *GeoM) Concat(other GeoM) {
-	if !g.initialized {
-		g.initialize()
-	}
 	result := GeoM{}
 	mul(&other, g, &result)
 	*g = result
 }
 
-// Add adds a geometry matrix with the other geometry matrix.
+// Add is deprecated.
 func (g *GeoM) Add(other GeoM) {
-	if !g.initialized {
-		g.initialize()
-	}
 	result := GeoM{}
 	add(&other, g, &result)
 	*g = result
@@ -74,63 +70,46 @@ func (g *GeoM) Add(other GeoM) {
 
 // Scale scales the matrix by (x, y).
 func (g *GeoM) Scale(x, y float64) {
-	if !g.initialized {
-		g.initialize()
-	}
 	for i := 0; i < GeoMDim; i++ {
-		g.es[i] *= x
-		g.es[GeoMDim+i] *= y
+		g.SetElement(0, i, g.Element(0, i)*x)
+		g.SetElement(1, i, g.Element(1, i)*y)
 	}
 }
 
 // Translate translates the matrix by (x, y).
 func (g *GeoM) Translate(tx, ty float64) {
-	if !g.initialized {
-		g.initialize()
-	}
-	g.es[2] += tx
-	g.es[GeoMDim+2] += ty
+	g.SetElement(0, 2, g.Element(0, 2)+tx)
+	g.SetElement(1, 2, g.Element(1, 2)+ty)
 }
 
 // Rotate rotates the matrix by theta.
 func (g *GeoM) Rotate(theta float64) {
 	sin, cos := math.Sincos(theta)
 	g.Concat(GeoM{
-		initialized: true,
-		es: [...]float64{
-			cos, -sin, 0,
-			sin, cos, 0,
-		},
+		values: geoMValueString([GeoMDim - 1][GeoMDim]float64{
+			{cos, -sin, 0},
+			{sin, cos, 0},
+		}),
 	})
 }
 
-// SetElement sets an element at (i, j).
-func (g *GeoM) SetElement(i, j int, element float64) {
-	if !g.initialized {
-		g.initialize()
-	}
-	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: [...]float64{
-			x, 0, 0,
-			0, y, 0,
-		},
+		values: geoMValueString([GeoMDim - 1][GeoMDim]float64{
+			{x, 0, 0},
+			{0, y, 0},
+		}),
 	}
 }
 
 // TranslateGeo is deprecated as of 1.2.0-alpha. Use Translate instead.
 func TranslateGeo(tx, ty float64) GeoM {
 	return GeoM{
-		initialized: true,
-		es: [...]float64{
-			1, 0, tx,
-			0, 1, ty,
-		},
+		values: geoMValueString([GeoMDim - 1][GeoMDim]float64{
+			{1, 0, tx},
+			{0, 1, ty},
+		}),
 	}
 }
 
@@ -138,10 +117,9 @@ func TranslateGeo(tx, ty float64) GeoM {
 func RotateGeo(theta float64) GeoM {
 	sin, cos := math.Sincos(theta)
 	return GeoM{
-		initialized: true,
-		es: [...]float64{
-			cos, -sin, 0,
-			sin, cos, 0,
-		},
+		values: geoMValueString([GeoMDim - 1][GeoMDim]float64{
+			{cos, -sin, 0},
+			{sin, cos, 0},
+		}),
 	}
 }