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moved text display to backend

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This commit is contained in:
Thomas Friedel 2019-02-21 16:47:09 +01:00
parent ac9a395c05
commit 43f040f777
4 changed files with 62 additions and 46 deletions
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1
backend/backendbase/base.go
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@ -18,6 +18,7 @@ type Backend interface {
Clear(pts [4][2]float64)
Fill(style *FillStyle, pts [][2]float64)
DrawImage(dimg Image, sx, sy, sw, sh, dx, dy, dw, dh float64, alpha float64)
FillImageMask(style *FillStyle, mask *image.Alpha, pts [4][2]float64)
}
// FillStyle is the color and other details on how to fill

52
backend/gogl/fill.go
View file

@ -1,6 +1,7 @@
package goglbackend
import (
"image"
"math"
"unsafe"
@ -117,6 +118,57 @@ func (b *GoGLBackend) Fill(style *backendbase.FillStyle, pts [][2]float64) {
}
}
func (b *GoGLBackend) FillImageMask(style *backendbase.FillStyle, mask *image.Alpha, pts [4][2]float64) {
w, h := mask.Rect.Dx(), mask.Rect.Dy()
gl.ActiveTexture(gl.TEXTURE1)
gl.BindTexture(gl.TEXTURE_2D, b.alphaTex)
for y := 0; y < h; y++ {
off := y * mask.Stride
gl.TexSubImage2D(gl.TEXTURE_2D, 0, 0, int32(alphaTexSize-1-y), int32(w), 1, gl.ALPHA, gl.UNSIGNED_BYTE, gl.Ptr(&mask.Pix[off]))
}
// b.drawTextShadow(textOffset, w, h, x, y)
gl.StencilFunc(gl.EQUAL, 0, 0xFF)
gl.BindBuffer(gl.ARRAY_BUFFER, b.buf)
vertex, alphaTexCoord := b.useAlphaShader(style, 1)
gl.EnableVertexAttribArray(vertex)
gl.EnableVertexAttribArray(alphaTexCoord)
tw := float64(w) / alphaTexSize
th := float64(h) / alphaTexSize
var buf [16]float32
data := buf[:0]
for _, pt := range pts {
data = append(data, float32(pt[0]), float32(pt[1]))
}
data = append(data, 0, 1, 0, float32(1-th), float32(tw), float32(1-th), float32(tw), 1)
gl.BufferData(gl.ARRAY_BUFFER, len(data)*4, unsafe.Pointer(&data[0]), gl.STREAM_DRAW)
gl.VertexAttribPointer(vertex, 2, gl.FLOAT, false, 0, nil)
gl.VertexAttribPointer(alphaTexCoord, 2, gl.FLOAT, false, 0, gl.PtrOffset(8*4))
gl.DrawArrays(gl.TRIANGLE_FAN, 0, 4)
gl.DisableVertexAttribArray(vertex)
gl.DisableVertexAttribArray(alphaTexCoord)
gl.ActiveTexture(gl.TEXTURE1)
gl.BindTexture(gl.TEXTURE_2D, b.alphaTex)
gl.StencilFunc(gl.ALWAYS, 0, 0xFF)
for y := 0; y < h; y++ {
gl.TexSubImage2D(gl.TEXTURE_2D, 0, 0, int32(alphaTexSize-1-y), int32(w), 1, gl.ALPHA, gl.UNSIGNED_BYTE, gl.Ptr(&zeroes[0]))
}
gl.ActiveTexture(gl.TEXTURE0)
}
func (b *GoGLBackend) drawBlurred(blur float64) {
gl.BlendFunc(gl.ONE, gl.ONE_MINUS_SRC_ALPHA)

2
backend/gogl/gogl.go
View file

@ -11,6 +11,8 @@ import (
const alphaTexSize = 2048
var zeroes [alphaTexSize]byte
type GoGLBackend struct {
x, y, w, h int
fx, fy, fw, fh float64

53
text.go
View file

@ -5,7 +5,6 @@ import (
"image"
"image/draw"
"io/ioutil"
"unsafe"
"github.com/golang/freetype"
"github.com/golang/freetype/truetype"
@ -210,52 +209,14 @@ func (cv *Canvas) FillText(str string, x, y float64) {
yOff = -float64(metrics.Descent) / 64
}
gli.ActiveTexture(gl_TEXTURE1)
gli.BindTexture(gl_TEXTURE_2D, alphaTex)
for y := 0; y < strHeight; y++ {
off := y * textImage.Stride
gli.TexSubImage2D(gl_TEXTURE_2D, 0, 0, int32(alphaTexSize-1-y), int32(strWidth), 1, gl_ALPHA, gl_UNSIGNED_BYTE, gli.Ptr(&textImage.Pix[off]))
}
var pts [4][2]float64
pts[0] = cv.tf(vec{float64(textOffset.X) + x, float64(textOffset.Y) + y + yOff})
pts[1] = cv.tf(vec{float64(textOffset.X) + x, float64(textOffset.Y+strHeight) + y + yOff})
pts[2] = cv.tf(vec{float64(textOffset.X+strWidth) + x, float64(textOffset.Y+strHeight) + y + yOff})
pts[3] = cv.tf(vec{float64(textOffset.X+strWidth) + x, float64(textOffset.Y) + y + yOff})
cv.drawTextShadow(textOffset, strWidth, strHeight, x, y)
gli.StencilFunc(gl_EQUAL, 0, 0xFF)
gli.BindBuffer(gl_ARRAY_BUFFER, buf)
vertex, alphaTexCoord := cv.useAlphaShader(&cv.state.fill, 1)
gli.EnableVertexAttribArray(vertex)
gli.EnableVertexAttribArray(alphaTexCoord)
p0 := cv.tf(vec{float64(textOffset.X) + x, float64(textOffset.Y) + y + yOff})
p1 := cv.tf(vec{float64(textOffset.X) + x, float64(textOffset.Y+strHeight) + y + yOff})
p2 := cv.tf(vec{float64(textOffset.X+strWidth) + x, float64(textOffset.Y+strHeight) + y + yOff})
p3 := cv.tf(vec{float64(textOffset.X+strWidth) + x, float64(textOffset.Y) + y + yOff})
tw := float64(strWidth) / alphaTexSize
th := float64(strHeight) / alphaTexSize
data := [16]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]),
0, 1, 0, float32(1 - th), float32(tw), float32(1 - th), float32(tw), 1}
gli.BufferData(gl_ARRAY_BUFFER, len(data)*4, unsafe.Pointer(&data[0]), gl_STREAM_DRAW)
gli.VertexAttribPointer(vertex, 2, gl_FLOAT, false, 0, 0)
gli.VertexAttribPointer(alphaTexCoord, 2, gl_FLOAT, false, 0, 8*4)
gli.DrawArrays(gl_TRIANGLE_FAN, 0, 4)
gli.DisableVertexAttribArray(vertex)
gli.DisableVertexAttribArray(alphaTexCoord)
gli.ActiveTexture(gl_TEXTURE1)
gli.BindTexture(gl_TEXTURE_2D, alphaTex)
gli.StencilFunc(gl_ALWAYS, 0, 0xFF)
for y := 0; y < strHeight; y++ {
gli.TexSubImage2D(gl_TEXTURE_2D, 0, 0, int32(alphaTexSize-1-y), int32(strWidth), 1, gl_ALPHA, gl_UNSIGNED_BYTE, gli.Ptr(&zeroes[0]))
}
gli.ActiveTexture(gl_TEXTURE0)
stl := cv.backendFillStyle(&cv.state.fill, 1)
cv.b.FillImageMask(&stl, textImage.SubImage(image.Rect(0, 0, strWidth, strHeight)).(*image.Alpha), pts)
}
// StrokeText draws the given string at the given coordinates