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font rendering fix

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This commit is contained in:
Thomas Friedel 2018-02-26 16:53:34 +01:00
parent da6538b1e3
commit 21d14699ec
2 changed files with 10 additions and 5 deletions
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4
canvas.go
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@ -131,7 +131,7 @@ loop:
}
}
const bufferTextureSize = 2048
const alphaTexSize = 2048
var (
gli GL
@ -248,7 +248,7 @@ func LoadGL(glimpl GL) (err error) {
gli.TexParameteri(gl_TEXTURE_2D, gl_TEXTURE_MAG_FILTER, gl_NEAREST)
gli.TexParameteri(gl_TEXTURE_2D, gl_TEXTURE_WRAP_S, gl_CLAMP_TO_EDGE)
gli.TexParameteri(gl_TEXTURE_2D, gl_TEXTURE_WRAP_T, gl_CLAMP_TO_EDGE)
gli.TexImage2D(gl_TEXTURE_2D, 0, gl_ALPHA, bufferTextureSize, bufferTextureSize, 0, gl_ALPHA, gl_UNSIGNED_BYTE, nil)
gli.TexImage2D(gl_TEXTURE_2D, 0, gl_ALPHA, alphaTexSize, alphaTexSize, 0, gl_ALPHA, gl_UNSIGNED_BYTE, nil)
gli.Enable(gl_BLEND)
gli.BlendFunc(gl_SRC_ALPHA, gl_ONE_MINUS_SRC_ALPHA)

11
text.go
View file

@ -19,6 +19,7 @@ type Font struct {
}
var fonts = make(map[string]*Font)
var zeroes [alphaTexSize]byte
func LoadFont(src interface{}, name string) (*Font, error) {
var f *Font
@ -94,15 +95,15 @@ func (cv *Canvas) FillText(str string, x, y float32) {
for y, w, h := 0, bounds.Dx(), bounds.Dy(); y < h; y++ {
off := y * mask.Stride
gli.TexSubImage2D(gl_TEXTURE_2D, 0, 0, int32(bufferTextureSize-1-y), int32(w), 1, gl_ALPHA, gl_UNSIGNED_BYTE, gli.Ptr(&mask.Pix[off]))
gli.TexSubImage2D(gl_TEXTURE_2D, 0, 0, int32(alphaTexSize-1-y), int32(w), 1, gl_ALPHA, gl_UNSIGNED_BYTE, gli.Ptr(&mask.Pix[off]))
}
p0 := cv.tf(lm.Vec2{float32(bounds.Min.X) + x, float32(bounds.Min.Y) + y})
p1 := cv.tf(lm.Vec2{float32(bounds.Min.X) + x, float32(bounds.Max.Y) + y})
p2 := cv.tf(lm.Vec2{float32(bounds.Max.X) + x, float32(bounds.Max.Y) + y})
p3 := cv.tf(lm.Vec2{float32(bounds.Max.X) + x, float32(bounds.Min.Y) + y})
tw := float32(bounds.Dx()) / bufferTextureSize
th := float32(bounds.Dy()) / bufferTextureSize
tw := float32(bounds.Dx()) / alphaTexSize
th := float32(bounds.Dy()) / alphaTexSize
data := [16]float32{p0[0], p0[1], p1[0], p1[1], p2[0], p2[1], p3[0], p3[1],
0, 1, 0, 1 - th, tw, 1 - th, tw, 1}
gli.BufferData(gl_ARRAY_BUFFER, len(data)*4, unsafe.Pointer(&data[0]), gl_STREAM_DRAW)
@ -111,6 +112,10 @@ func (cv *Canvas) FillText(str string, x, y float32) {
gli.VertexAttribPointer(alphaTexCoord, 2, gl_FLOAT, false, 0, gli.PtrOffset(8*4))
gli.DrawArrays(gl_TRIANGLE_FAN, 0, 4)
for y, w, h := 0, bounds.Dx(), bounds.Dy(); y < h; y++ {
gli.TexSubImage2D(gl_TEXTURE_2D, 0, 0, int32(alphaTexSize-1-y), int32(w), 1, gl_ALPHA, gl_UNSIGNED_BYTE, gli.Ptr(&zeroes[0]))
}
x += float32(advance) / 64
}