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more general backend fill function

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This commit is contained in:
Thomas Friedel 2019-02-17 11:52:53 +01:00
parent 114b292be7
commit 359b52f473
5 changed files with 76 additions and 15 deletions
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2
backend.go
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@ -5,5 +5,5 @@ import "github.com/tfriedel6/canvas/backend/backendbase"
type Backend interface {
ClearRect(x, y, w, h int)
Clear(pts [4][2]float64)
Fill(style *backendbase.Style, pts [4][2]float64)
Fill(style *backendbase.Style, pts [][2]float64)
}

70
backend/gogl/fill.go
View file

@ -35,19 +35,19 @@ func (b *GoGLBackend) FillRect(x, y, w, h float64) {
cv.drawShadow(tris[:])
}
gl.BindBuffer(gl_ARRAY_BUFFER, buf)
gl.BindBuffer(gl.ARRAY_BUFFER, buf)
data := [8]float32{float32(p0[0]), float32(p0[1]), float32(p1[0]), float32(p1[1]), float32(p2[0]), float32(p2[1]), float32(p3[0]), float32(p3[1])}
gl.BufferData(gl_ARRAY_BUFFER, len(data)*4, unsafe.Pointer(&data[0]), gl_STREAM_DRAW)
gl.BufferData(gl.ARRAY_BUFFER, len(data)*4, unsafe.Pointer(&data[0]), gl.STREAM_DRAW)
gl.StencilFunc(gl_EQUAL, 0, 0xFF)
gl.StencilFunc(gl.EQUAL, 0, 0xFF)
vertex := cv.useShader(&cv.state.fill)
gl.VertexAttribPointer(vertex, 2, gl_FLOAT, false, 0, 0)
gl.VertexAttribPointer(vertex, 2, gl.FLOAT, false, 0, 0)
gl.EnableVertexAttribArray(vertex)
gl.DrawArrays(gl_TRIANGLE_FAN, 0, 4)
gl.DrawArrays(gl.TRIANGLE_FAN, 0, 4)
gl.DisableVertexAttribArray(vertex)
gl.StencilFunc(gl_ALWAYS, 0, 0xFF)
gl.StencilFunc(gl.ALWAYS, 0, 0xFF)
}
*/
@ -88,6 +88,7 @@ func (b *GoGLBackend) Clear(pts [4][2]float64) {
gl.Enable(gl.BLEND)
}
/*
func (b *GoGLBackend) Fill(style *backendbase.Style, pts [4][2]float64) {
gl.BindBuffer(gl.ARRAY_BUFFER, b.buf)
data := [8]float32{
@ -107,3 +108,60 @@ func (b *GoGLBackend) Fill(style *backendbase.Style, pts [4][2]float64) {
gl.StencilFunc(gl.ALWAYS, 0, 0xFF)
}
*/
func (b *GoGLBackend) Fill(style *backendbase.Style, pts [][2]float64) {
b.ptsBuf = b.ptsBuf[:0]
for _, pt := range pts {
b.ptsBuf = append(b.ptsBuf, float32(pt[0]), float32(pt[1]))
}
mode := uint32(gl.TRIANGLES)
if len(pts) == 4 {
mode = gl.TRIANGLE_FAN
}
gl.BindBuffer(gl.ARRAY_BUFFER, b.buf)
gl.BufferData(gl.ARRAY_BUFFER, len(b.ptsBuf)*4, unsafe.Pointer(&b.ptsBuf[0]), gl.STREAM_DRAW)
if style.GlobalAlpha >= 1 { // && cv.state.fill.isOpaque() {
vertex := b.useShader(style)
gl.EnableVertexAttribArray(vertex)
gl.VertexAttribPointer(vertex, 2, gl.FLOAT, false, 0, nil)
gl.DrawArrays(mode, 0, int32(len(b.ptsBuf)/2))
gl.DisableVertexAttribArray(vertex)
} else {
gl.ColorMask(false, false, false, false)
gl.StencilFunc(gl.ALWAYS, 1, 0xFF)
gl.StencilOp(gl.REPLACE, gl.REPLACE, gl.REPLACE)
gl.StencilMask(0x01)
gl.UseProgram(b.sr.ID)
gl.Uniform4f(b.sr.Color, 0, 0, 0, 0)
gl.Uniform2f(b.sr.CanvasSize, float32(b.fw), float32(b.fh))
gl.EnableVertexAttribArray(b.sr.Vertex)
gl.VertexAttribPointer(b.sr.Vertex, 2, gl.FLOAT, false, 0, nil)
gl.DrawArrays(mode, 0, int32(len(b.ptsBuf)/2))
gl.DisableVertexAttribArray(b.sr.Vertex)
gl.ColorMask(true, true, true, true)
gl.StencilFunc(gl.EQUAL, 1, 0xFF)
vertex := b.useShader(style)
gl.EnableVertexAttribArray(vertex)
gl.VertexAttribPointer(vertex, 2, gl.FLOAT, false, 0, nil)
b.ptsBuf = append(b.ptsBuf[:0], 0, 0, float32(b.fw), 0, float32(b.fw), float32(b.fh), 0, float32(b.fh))
gl.DrawArrays(gl.TRIANGLE_FAN, 0, 4)
gl.DisableVertexAttribArray(vertex)
gl.StencilOp(gl.KEEP, gl.KEEP, gl.KEEP)
gl.StencilFunc(gl.ALWAYS, 0, 0xFF)
gl.Clear(gl.STENCIL_BUFFER_BIT)
gl.StencilMask(0xFF)
}
}

3
backend/gogl/gogl.go
View file

@ -33,6 +33,8 @@ type GoGLBackend struct {
offscr1 offscreenBuffer
offscr2 offscreenBuffer
glChan chan func()
ptsBuf []float32
}
type offscreenBuffer struct {
@ -57,6 +59,7 @@ func New(x, y, w, h int) (canvas.Backend, error) {
h: h,
fw: float64(w),
fh: float64(h),
ptsBuf: make([]float32, 0, 4096),
}
err = loadShader(solidVS, solidFS, &b.sr.shaderProgram)

4
canvas.go
View file

@ -493,10 +493,10 @@ func (s *drawStyle) isOpaque() bool {
return s.color.A >= 255
}
func (cv *Canvas) backendStyle(s *drawStyle) backendbase.Style {
func (cv *Canvas) backendStyle(s *drawStyle, alpha float64) backendbase.Style {
return backendbase.Style{
Color: s.color,
GlobalAlpha: cv.state.globalAlpha,
GlobalAlpha: cv.state.globalAlpha * alpha,
}
}

4
paths.go
View file

@ -648,8 +648,8 @@ func (cv *Canvas) FillRect(x, y, w, h float64) {
data := [4][2]float64{{p0[0], p0[1]}, {p1[0], p1[1]}, {p2[0], p2[1]}, {p3[0], p3[1]}}
stl := cv.backendStyle(&cv.state.fill)
cv.b.Fill(&stl, data)
stl := cv.backendStyle(&cv.state.fill, 1)
cv.b.Fill(&stl, data[:])
}
// ClearRect sets the color of the rectangle to transparent black