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implemented software gradients

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This commit is contained in:
Thomas Friedel 2019-04-24 13:22:24 +02:00
parent e3bb07a09c
commit a913b8b33b
3 changed files with 64 additions and 13 deletions
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2
backend/gogl/shaders.go
View file

@ -244,7 +244,7 @@ void main() {
return;
}
float o = max(o1, o2);
float r = radFrom + o * (radTo - radFrom);
//float r = radFrom + o * (radTo - radFrom);
vec4 col = texture2D(gradient, vec2(o, 0.0));
col.a *= texture2D(alphaTex, v_atc).a * globalAlpha;
gl_FragColor = col;

59
backend/software/fill.go
View file

@ -3,6 +3,7 @@ package softwarebackend
import (
"image"
"image/color"
"math"
"github.com/tfriedel6/canvas/backend/backendbase"
)
@ -19,23 +20,50 @@ func (b *SoftwareBackend) Clear(pts [4][2]float64) {
}
func (b *SoftwareBackend) Fill(style *backendbase.FillStyle, pts [][2]float64) {
p2 := b.mask.Pix
for i := range p2 {
p2[i] = 0
}
b.clearMask()
iterateTriangles(pts[:], func(tri [][2]float64) {
b.fillTriangle(tri, func(x, y int) {
if b.clip.AlphaAt(x, y).A == 0 {
if lg := style.LinearGradient; lg != nil {
lg := lg.(*LinearGradient)
from := [2]float64{style.Gradient.X0, style.Gradient.Y0}
dir := [2]float64{style.Gradient.X1 - style.Gradient.X0, style.Gradient.Y1 - style.Gradient.Y0}
dirlen := math.Sqrt(dir[0]*dir[0] + dir[1]*dir[1])
dir[0] /= dirlen
dir[1] /= dirlen
b.fillTriangles(pts, func(x, y int) {
pos := [2]float64{float64(x) - from[0], float64(y) - from[1]}
r := (pos[0]*dir[0] + pos[1]*dir[1]) / dirlen
color := lg.data.ColorAt(r)
b.Image.SetRGBA(x, y, mix(color, b.Image.RGBAAt(x, y)))
})
} else if rg := style.RadialGradient; rg != nil {
rg := rg.(*RadialGradient)
from := [2]float64{style.Gradient.X0, style.Gradient.Y0}
to := [2]float64{style.Gradient.X1, style.Gradient.Y1}
radFrom := style.Gradient.RadFrom
radTo := style.Gradient.RadTo
b.fillTriangles(pts, func(x, y int) {
pos := [2]float64{float64(x), float64(y)}
oa := 0.5 * math.Sqrt(
math.Pow(-2.0*from[0]*from[0]+2.0*from[0]*to[0]+2.0*from[0]*pos[0]-2.0*to[0]*pos[0]-2.0*from[1]*from[1]+2.0*from[1]*to[1]+2.0*from[1]*pos[1]-2.0*to[1]*pos[1]+2.0*radFrom*radFrom-2.0*radFrom*radTo, 2.0)-
4.0*(from[0]*from[0]-2.0*from[0]*pos[0]+pos[0]*pos[0]+from[1]*from[1]-2.0*from[1]*pos[1]+pos[1]*pos[1]-radFrom*radFrom)*
(from[0]*from[0]-2.0*from[0]*to[0]+to[0]*to[0]+from[1]*from[1]-2.0*from[1]*to[1]+to[1]*to[1]-radFrom*radFrom+2.0*radFrom*radTo-radTo*radTo))
ob := (from[0]*from[0] - from[0]*to[0] - from[0]*pos[0] + to[0]*pos[0] + from[1]*from[1] - from[1]*to[1] - from[1]*pos[1] + to[1]*pos[1] - radFrom*radFrom + radFrom*radTo)
oc := (from[0]*from[0] - 2.0*from[0]*to[0] + to[0]*to[0] + from[1]*from[1] - 2.0*from[1]*to[1] + to[1]*to[1] - radFrom*radFrom + 2.0*radFrom*radTo - radTo*radTo)
o1 := (-oa + ob) / oc
o2 := (oa + ob) / oc
if math.IsNaN(o1) && math.IsNaN(o2) {
return
}
if b.mask.AlphaAt(x, y).A > 0 {
return
}
b.mask.SetAlpha(x, y, color.Alpha{A: 255})
o := math.Max(o1, o2)
col := rg.data.ColorAt(o)
b.Image.SetRGBA(x, y, mix(col, b.Image.RGBAAt(x, y)))
b.Image.SetRGBA(x, y, color.RGBA{R: 255, A: 255})
})
} else {
b.fillTriangles(pts, func(x, y int) {
b.Image.SetRGBA(x, y, mix(style.Color, b.Image.RGBAAt(x, y)))
})
})
}
}
func (b *SoftwareBackend) FillImageMask(style *backendbase.FillStyle, mask *image.Alpha, pts [4][2]float64) {
@ -52,6 +80,13 @@ func (b *SoftwareBackend) FillImageMask(style *backendbase.FillStyle, mask *imag
})
}
func (b *SoftwareBackend) clearMask() {
p := b.mask.Pix
for i := range p {
p[i] = 0
}
}
func (b *SoftwareBackend) ClearClip() {
p := b.clip.Pix
for i := range p {

16
backend/software/triangles.go
View file

@ -1,6 +1,7 @@
package softwarebackend
import (
"image/color"
"math"
)
@ -173,3 +174,18 @@ func iterateTriangles(pts [][2]float64, fn func(tri [][2]float64)) {
fn(pts[i-3 : i])
}
}
func (b *SoftwareBackend) fillTriangles(pts [][2]float64, fn func(x, y int)) {
iterateTriangles(pts[:], func(tri [][2]float64) {
b.fillTriangle(tri, func(x, y int) {
if b.clip.AlphaAt(x, y).A == 0 {
return
}
if b.mask.AlphaAt(x, y).A > 0 {
return
}
b.mask.SetAlpha(x, y, color.Alpha{A: 255})
fn(x, y)
})
})
}