308 lines
8.8 KiB
Go
308 lines
8.8 KiB
Go
package goglbackend
|
|
|
|
import (
|
|
"image"
|
|
"math"
|
|
"unsafe"
|
|
|
|
"github.com/tfriedel6/canvas/backend/backendbase"
|
|
"github.com/tfriedel6/canvas/backend/goglbackend/gl"
|
|
)
|
|
|
|
func (b *GoGLBackend) Clear(pts [4][2]float64) {
|
|
b.activate()
|
|
|
|
// first check if the four points are aligned to form a nice rectangle, which can be more easily
|
|
// cleared using glScissor and glClear
|
|
aligned := pts[0][0] == pts[1][0] && pts[2][0] == pts[3][0] && pts[0][1] == pts[3][1] && pts[1][1] == pts[2][1]
|
|
if !aligned {
|
|
aligned = pts[0][0] == pts[3][0] && pts[1][0] == pts[2][0] && pts[0][1] == pts[1][1] && pts[2][1] == pts[3][1]
|
|
}
|
|
if aligned {
|
|
minX := math.Floor(math.Min(pts[0][0], pts[2][0]))
|
|
maxX := math.Ceil(math.Max(pts[0][0], pts[2][0]))
|
|
minY := math.Floor(math.Min(pts[0][1], pts[2][1]))
|
|
maxY := math.Ceil(math.Max(pts[0][1], pts[2][1]))
|
|
b.clearRect(int(minX), int(minY), int(maxX)-int(minX), int(maxY)-int(minY))
|
|
return
|
|
}
|
|
|
|
data := [8]float32{
|
|
float32(pts[0][0]), float32(pts[0][1]),
|
|
float32(pts[1][0]), float32(pts[1][1]),
|
|
float32(pts[2][0]), float32(pts[2][1]),
|
|
float32(pts[3][0]), float32(pts[3][1])}
|
|
|
|
gl.UseProgram(b.sr.ID)
|
|
gl.Uniform2f(b.sr.CanvasSize, float32(b.fw), float32(b.fh))
|
|
gl.Uniform4f(b.sr.Color, 0, 0, 0, 0)
|
|
gl.Uniform1f(b.sr.GlobalAlpha, 1)
|
|
|
|
gl.Disable(gl.BLEND)
|
|
|
|
gl.BindBuffer(gl.ARRAY_BUFFER, b.buf)
|
|
gl.BufferData(gl.ARRAY_BUFFER, len(data)*4, unsafe.Pointer(&data[0]), gl.STREAM_DRAW)
|
|
|
|
gl.StencilFunc(gl.EQUAL, 0, 0xFF)
|
|
|
|
gl.VertexAttribPointer(b.sr.Vertex, 2, gl.FLOAT, false, 0, nil)
|
|
gl.EnableVertexAttribArray(b.sr.Vertex)
|
|
gl.DrawArrays(gl.TRIANGLE_FAN, 0, 4)
|
|
gl.DisableVertexAttribArray(b.sr.Vertex)
|
|
|
|
gl.StencilFunc(gl.ALWAYS, 0, 0xFF)
|
|
|
|
gl.Enable(gl.BLEND)
|
|
}
|
|
|
|
func (b *GoGLBackend) clearRect(x, y, w, h int) {
|
|
gl.Enable(gl.SCISSOR_TEST)
|
|
|
|
var box [4]int32
|
|
gl.GetIntegerv(gl.SCISSOR_BOX, &box[0])
|
|
|
|
gl.Scissor(int32(x), int32(b.h-y-h), int32(w), int32(h))
|
|
gl.ClearColor(0, 0, 0, 0)
|
|
gl.Clear(gl.COLOR_BUFFER_BIT)
|
|
gl.Scissor(box[0], box[1], box[2], box[3])
|
|
|
|
gl.Disable(gl.SCISSOR_TEST)
|
|
}
|
|
|
|
func (b *GoGLBackend) Fill(style *backendbase.FillStyle, pts [][2]float64) {
|
|
b.activate()
|
|
|
|
if style.Blur > 0 {
|
|
b.offscr1.alpha = true
|
|
b.enableTextureRenderTarget(&b.offscr1)
|
|
gl.ClearColor(0, 0, 0, 0)
|
|
gl.Clear(gl.COLOR_BUFFER_BIT | gl.STENCIL_BUFFER_BIT)
|
|
}
|
|
|
|
b.ptsBuf = b.ptsBuf[:0]
|
|
b.ptsBuf = append(b.ptsBuf,
|
|
0, 0,
|
|
0, float32(b.fh),
|
|
float32(b.fw), float32(b.fh),
|
|
float32(b.fw), 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.Color.A >= 255 {
|
|
vertex := b.useShader(style)
|
|
|
|
gl.StencilFunc(gl.EQUAL, 0, 0xFF)
|
|
gl.EnableVertexAttribArray(vertex)
|
|
gl.VertexAttribPointer(vertex, 2, gl.FLOAT, false, 0, nil)
|
|
gl.DrawArrays(mode, 4, int32(len(pts)))
|
|
gl.DisableVertexAttribArray(vertex)
|
|
gl.StencilFunc(gl.ALWAYS, 0, 0xFF)
|
|
} 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.Uniform1f(b.sr.GlobalAlpha, 1)
|
|
|
|
gl.EnableVertexAttribArray(b.sr.Vertex)
|
|
gl.VertexAttribPointer(b.sr.Vertex, 2, gl.FLOAT, false, 0, nil)
|
|
gl.DrawArrays(mode, 4, int32(len(pts)))
|
|
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)
|
|
}
|
|
|
|
if style.Blur > 0 {
|
|
b.drawBlurred(style.Blur)
|
|
}
|
|
}
|
|
|
|
func (b *GoGLBackend) FillImageMask(style *backendbase.FillStyle, mask *image.Alpha, pts [4][2]float64) {
|
|
b.activate()
|
|
|
|
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]))
|
|
}
|
|
|
|
if style.Blur > 0 {
|
|
b.offscr1.alpha = true
|
|
b.enableTextureRenderTarget(&b.offscr1)
|
|
gl.ClearColor(0, 0, 0, 0)
|
|
gl.Clear(gl.COLOR_BUFFER_BIT | gl.STENCIL_BUFFER_BIT)
|
|
}
|
|
|
|
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)
|
|
|
|
if style.Blur > 0 {
|
|
b.drawBlurred(style.Blur)
|
|
}
|
|
}
|
|
|
|
func (b *GoGLBackend) drawBlurred(blur float64) {
|
|
gl.BlendFunc(gl.ONE, gl.ONE_MINUS_SRC_ALPHA)
|
|
|
|
var kernel []float32
|
|
var kernelBuf [255]float32
|
|
var gs *gaussianShader
|
|
if blur < 3 {
|
|
gs = &b.gauss15r
|
|
kernel = kernelBuf[:15]
|
|
} else if blur < 12 {
|
|
gs = &b.gauss63r
|
|
kernel = kernelBuf[:63]
|
|
} else {
|
|
gs = &b.gauss127r
|
|
kernel = kernelBuf[:127]
|
|
}
|
|
|
|
gaussianKernel(blur, kernel)
|
|
|
|
b.offscr2.alpha = true
|
|
b.enableTextureRenderTarget(&b.offscr2)
|
|
gl.ClearColor(0, 0, 0, 0)
|
|
gl.Clear(gl.COLOR_BUFFER_BIT | gl.STENCIL_BUFFER_BIT)
|
|
|
|
gl.StencilFunc(gl.EQUAL, 0, 0xFF)
|
|
|
|
gl.BindBuffer(gl.ARRAY_BUFFER, b.shadowBuf)
|
|
data := [16]float32{0, 0, 0, float32(b.h), float32(b.w), float32(b.h), float32(b.w), 0, 0, 0, 0, 1, 1, 1, 1, 0}
|
|
gl.BufferData(gl.ARRAY_BUFFER, len(data)*4, unsafe.Pointer(&data[0]), gl.STREAM_DRAW)
|
|
|
|
gl.ActiveTexture(gl.TEXTURE0)
|
|
gl.BindTexture(gl.TEXTURE_2D, b.offscr1.tex)
|
|
|
|
gl.UseProgram(gs.ID)
|
|
gl.Uniform1i(gs.Image, 0)
|
|
gl.Uniform2f(gs.CanvasSize, float32(b.fw), float32(b.fh))
|
|
gl.Uniform2f(gs.KernelScale, 1.0/float32(b.fw), 0.0)
|
|
gl.Uniform1fv(gs.Kernel, int32(len(kernel)), &kernel[0])
|
|
gl.VertexAttribPointer(gs.Vertex, 2, gl.FLOAT, false, 0, nil)
|
|
gl.VertexAttribPointer(gs.TexCoord, 2, gl.FLOAT, false, 0, gl.PtrOffset(8*4))
|
|
gl.EnableVertexAttribArray(gs.Vertex)
|
|
gl.EnableVertexAttribArray(gs.TexCoord)
|
|
gl.DrawArrays(gl.TRIANGLE_FAN, 0, 4)
|
|
gl.DisableVertexAttribArray(gs.Vertex)
|
|
gl.DisableVertexAttribArray(gs.TexCoord)
|
|
|
|
gl.StencilFunc(gl.ALWAYS, 0, 0xFF)
|
|
|
|
b.disableTextureRenderTarget()
|
|
|
|
gl.StencilFunc(gl.EQUAL, 0, 0xFF)
|
|
|
|
gl.BindBuffer(gl.ARRAY_BUFFER, b.shadowBuf)
|
|
data = [16]float32{0, 0, 0, float32(b.h), float32(b.w), float32(b.h), float32(b.w), 0, 0, 0, 0, 1, 1, 1, 1, 0}
|
|
gl.BufferData(gl.ARRAY_BUFFER, len(data)*4, unsafe.Pointer(&data[0]), gl.STREAM_DRAW)
|
|
|
|
gl.ActiveTexture(gl.TEXTURE0)
|
|
gl.BindTexture(gl.TEXTURE_2D, b.offscr2.tex)
|
|
|
|
gl.UseProgram(gs.ID)
|
|
gl.Uniform1i(gs.Image, 0)
|
|
gl.Uniform2f(gs.CanvasSize, float32(b.fw), float32(b.fh))
|
|
gl.Uniform2f(gs.KernelScale, 0.0, 1.0/float32(b.fh))
|
|
gl.Uniform1fv(gs.Kernel, int32(len(kernel)), &kernel[0])
|
|
gl.VertexAttribPointer(gs.Vertex, 2, gl.FLOAT, false, 0, nil)
|
|
gl.VertexAttribPointer(gs.TexCoord, 2, gl.FLOAT, false, 0, gl.PtrOffset(8*4))
|
|
gl.EnableVertexAttribArray(gs.Vertex)
|
|
gl.EnableVertexAttribArray(gs.TexCoord)
|
|
gl.DrawArrays(gl.TRIANGLE_FAN, 0, 4)
|
|
gl.DisableVertexAttribArray(gs.Vertex)
|
|
gl.DisableVertexAttribArray(gs.TexCoord)
|
|
|
|
gl.StencilFunc(gl.ALWAYS, 0, 0xFF)
|
|
|
|
gl.BlendFunc(gl.SRC_ALPHA, gl.ONE_MINUS_SRC_ALPHA)
|
|
}
|
|
|
|
func gaussianKernel(stddev float64, target []float32) {
|
|
stddevSqr := stddev * stddev
|
|
center := float64(len(target) / 2)
|
|
factor := 1.0 / math.Sqrt(2*math.Pi*stddevSqr)
|
|
for i := range target {
|
|
x := float64(i) - center
|
|
target[i] = float32(factor * math.Pow(math.E, -x*x/(2*stddevSqr)))
|
|
}
|
|
// normalizeKernel(target)
|
|
}
|
|
|
|
func normalizeKernel(kernel []float32) {
|
|
var sum float32
|
|
for _, v := range kernel {
|
|
sum += v
|
|
}
|
|
factor := 1.0 / sum
|
|
for i := range kernel {
|
|
kernel[i] *= factor
|
|
}
|
|
}
|