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Add RotateHue

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This commit is contained in:
Hajime Hoshi 2014-12-15 01:45:41 +09:00
parent d25d5f39b0
commit d5f8e79c88
2 changed files with 32 additions and 5 deletions
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23
colormatrix.go
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@ -68,9 +68,9 @@ func (c *ColorMatrix) setElement(i, j int, element float64) {
// Monochrome returns a color matrix to make an image monochrome.
func Monochrome() ColorMatrix {
const r float64 = 6968.0 / 32768.0
const g float64 = 23434.0 / 32768.0
const b float64 = 2366.0 / 32768.0
const r = 6968.0 / 32768.0
const g = 23434.0 / 32768.0
const b = 2366.0 / 32768.0
return ColorMatrix{
[ColorMatrixDim - 1][ColorMatrixDim]float64{
{r, g, b, 0, 0},
@ -81,6 +81,23 @@ func Monochrome() ColorMatrix {
}
}
// RotateHue returns a color matrix to rotate the hue
func RotateHue(theta float64) ColorMatrix {
sin, cos := math.Sincos(theta)
v1 := cos + (1.0-cos)/3.0
v2 := 1.0/3.0*(1.0-cos) - math.Sqrt(1.0/3.0)*sin
v3 := 1.0/3.0*(1.0-cos) + math.Sqrt(1.0/3.0)*sin
// TODO: Need to clamp the values between 0 and 1?
return ColorMatrix{
[ColorMatrixDim - 1][ColorMatrixDim]float64{
{v1, v2, v3, 0, 0},
{v3, v1, v2, 0, 0},
{v2, v3, v1, 0, 0},
{0, 0, 0, 1, 0},
},
}
}
func rgba(clr color.Color) (float64, float64, float64, float64) {
r, g, b, a := clr.RGBA()
rf := float64(r) / float64(math.MaxUint16)

14
example/paint/main.go
View File

@ -4,7 +4,9 @@ import (
"fmt"
"github.com/hajimehoshi/ebiten"
"github.com/hajimehoshi/ebiten/ebitenutil"
"image/color"
"log"
"math"
"runtime"
)
@ -14,11 +16,15 @@ const (
)
type Game struct {
count int
brushRenderTarget ebiten.RenderTargetID
canvasRenderTarget ebiten.RenderTargetID
}
func (g *Game) Update() error {
if ebiten.IsMouseButtonPressed(ebiten.MouseButtonLeft) {
g.count++
}
return nil
}
@ -31,7 +37,7 @@ func (g *Game) Draw(gr ebiten.GraphicsContext) error {
}
gr.PushRenderTarget(g.brushRenderTarget)
gr.Fill(0, 0, 0)
gr.Fill(0xff, 0xff, 0xff)
gr.PopRenderTarget()
}
if g.canvasRenderTarget.IsNil() {
@ -50,7 +56,11 @@ func (g *Game) Draw(gr ebiten.GraphicsContext) error {
gr.PushRenderTarget(g.canvasRenderTarget)
geo := ebiten.GeometryMatrixI()
geo.Translate(float64(mx), float64(my))
ebiten.DrawWhole(gr.RenderTarget(g.brushRenderTarget), 1, 1, geo, ebiten.ColorMatrixI())
clr := ebiten.ColorMatrixI()
clr.Scale(color.RGBA{0xff, 0xff, 0x00, 0xff})
theta := 2.0 * math.Pi * float64(g.count%60) / 60.0
clr.Concat(ebiten.RotateHue(theta))
ebiten.DrawWhole(gr.RenderTarget(g.brushRenderTarget), 1, 1, geo, clr)
gr.PopRenderTarget()
}