308 lines
9.2 KiB
Go
Executable file
308 lines
9.2 KiB
Go
Executable file
package xmobilebackend
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import (
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"image"
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"math"
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"unsafe"
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"github.com/tfriedel6/canvas/backend/backendbase"
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"golang.org/x/mobile/gl"
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)
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func (b *XMobileBackend) Clear(pts [4][2]float64) {
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b.activate()
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// first check if the four points are aligned to form a nice rectangle, which can be more easily
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// cleared using glScissor and glClear
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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]
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if !aligned {
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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]
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}
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if aligned {
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minX := math.Floor(math.Min(pts[0][0], pts[2][0]))
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maxX := math.Ceil(math.Max(pts[0][0], pts[2][0]))
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minY := math.Floor(math.Min(pts[0][1], pts[2][1]))
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maxY := math.Ceil(math.Max(pts[0][1], pts[2][1]))
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b.clearRect(int(minX), int(minY), int(maxX)-int(minX), int(maxY)-int(minY))
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return
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}
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data := [8]float32{
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float32(pts[0][0]), float32(pts[0][1]),
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float32(pts[1][0]), float32(pts[1][1]),
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float32(pts[2][0]), float32(pts[2][1]),
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float32(pts[3][0]), float32(pts[3][1])}
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b.glctx.UseProgram(b.sr.ID)
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b.glctx.Uniform2f(b.sr.CanvasSize, float32(b.fw), float32(b.fh))
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b.glctx.Uniform4f(b.sr.Color, 0, 0, 0, 0)
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b.glctx.Uniform1f(b.sr.GlobalAlpha, 1)
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b.glctx.Disable(gl.BLEND)
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b.glctx.BindBuffer(gl.ARRAY_BUFFER, b.buf)
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b.glctx.BufferData(gl.ARRAY_BUFFER, byteSlice(unsafe.Pointer(&data[0]), len(data)*4), gl.STREAM_DRAW)
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b.glctx.StencilFunc(gl.EQUAL, 0, 0xFF)
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b.glctx.VertexAttribPointer(b.sr.Vertex, 2, gl.FLOAT, false, 0, 0)
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b.glctx.EnableVertexAttribArray(b.sr.Vertex)
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b.glctx.DrawArrays(gl.TRIANGLE_FAN, 0, 4)
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b.glctx.DisableVertexAttribArray(b.sr.Vertex)
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b.glctx.StencilFunc(gl.ALWAYS, 0, 0xFF)
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b.glctx.Enable(gl.BLEND)
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}
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func (b *XMobileBackend) clearRect(x, y, w, h int) {
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b.glctx.Enable(gl.SCISSOR_TEST)
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var box [4]int32
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b.glctx.GetIntegerv(box[:], gl.SCISSOR_BOX)
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b.glctx.Scissor(int32(x), int32(b.h-y-h), int32(w), int32(h))
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b.glctx.ClearColor(0, 0, 0, 0)
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b.glctx.Clear(gl.COLOR_BUFFER_BIT)
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b.glctx.Scissor(box[0], box[1], box[2], box[3])
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b.glctx.Disable(gl.SCISSOR_TEST)
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}
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func (b *XMobileBackend) Fill(style *backendbase.FillStyle, pts [][2]float64) {
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b.activate()
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if style.Blur > 0 {
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b.offscr1.alpha = true
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b.enableTextureRenderTarget(&b.offscr1)
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b.glctx.ClearColor(0, 0, 0, 0)
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b.glctx.Clear(gl.COLOR_BUFFER_BIT | gl.STENCIL_BUFFER_BIT)
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}
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b.ptsBuf = b.ptsBuf[:0]
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b.ptsBuf = append(b.ptsBuf,
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0, 0,
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0, float32(b.fh),
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float32(b.fw), float32(b.fh),
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float32(b.fw), 0)
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for _, pt := range pts {
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b.ptsBuf = append(b.ptsBuf, float32(pt[0]), float32(pt[1]))
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}
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mode := gl.Enum(gl.TRIANGLES)
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if len(pts) == 4 {
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mode = gl.TRIANGLE_FAN
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}
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b.glctx.BindBuffer(gl.ARRAY_BUFFER, b.buf)
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b.glctx.BufferData(gl.ARRAY_BUFFER, byteSlice(unsafe.Pointer(&b.ptsBuf[0]), len(b.ptsBuf)*4), gl.STREAM_DRAW)
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if style.Color.A >= 255 {
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vertex := b.useShader(style)
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b.glctx.StencilFunc(gl.EQUAL, 0, 0xFF)
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b.glctx.EnableVertexAttribArray(vertex)
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b.glctx.VertexAttribPointer(vertex, 2, gl.FLOAT, false, 0, 0)
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b.glctx.DrawArrays(mode, 4, len(pts))
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b.glctx.DisableVertexAttribArray(vertex)
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b.glctx.StencilFunc(gl.ALWAYS, 0, 0xFF)
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} else {
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b.glctx.ColorMask(false, false, false, false)
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b.glctx.StencilFunc(gl.ALWAYS, 1, 0xFF)
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b.glctx.StencilOp(gl.REPLACE, gl.REPLACE, gl.REPLACE)
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b.glctx.StencilMask(0x01)
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b.glctx.UseProgram(b.sr.ID)
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b.glctx.Uniform4f(b.sr.Color, 0, 0, 0, 0)
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b.glctx.Uniform2f(b.sr.CanvasSize, float32(b.fw), float32(b.fh))
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b.glctx.Uniform1f(b.sr.GlobalAlpha, 1)
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b.glctx.EnableVertexAttribArray(b.sr.Vertex)
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b.glctx.VertexAttribPointer(b.sr.Vertex, 2, gl.FLOAT, false, 0, 0)
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b.glctx.DrawArrays(mode, 4, len(pts))
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b.glctx.DisableVertexAttribArray(b.sr.Vertex)
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b.glctx.ColorMask(true, true, true, true)
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b.glctx.StencilFunc(gl.EQUAL, 1, 0xFF)
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vertex := b.useShader(style)
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b.glctx.EnableVertexAttribArray(vertex)
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b.glctx.VertexAttribPointer(vertex, 2, gl.FLOAT, false, 0, 0)
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b.ptsBuf = append(b.ptsBuf[:0], 0, 0, float32(b.fw), 0, float32(b.fw), float32(b.fh), 0, float32(b.fh))
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b.glctx.DrawArrays(gl.TRIANGLE_FAN, 0, 4)
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b.glctx.DisableVertexAttribArray(vertex)
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b.glctx.StencilOp(gl.KEEP, gl.KEEP, gl.KEEP)
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b.glctx.StencilFunc(gl.ALWAYS, 0, 0xFF)
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b.glctx.Clear(gl.STENCIL_BUFFER_BIT)
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b.glctx.StencilMask(0xFF)
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}
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if style.Blur > 0 {
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b.drawBlurred(style.Blur)
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}
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}
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func (b *XMobileBackend) FillImageMask(style *backendbase.FillStyle, mask *image.Alpha, pts [4][2]float64) {
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b.activate()
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w, h := mask.Rect.Dx(), mask.Rect.Dy()
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b.glctx.ActiveTexture(gl.TEXTURE1)
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b.glctx.BindTexture(gl.TEXTURE_2D, b.alphaTex)
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for y := 0; y < h; y++ {
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off := y * mask.Stride
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b.glctx.TexSubImage2D(gl.TEXTURE_2D, 0, 0, alphaTexSize-1-y, w, 1, gl.ALPHA, gl.UNSIGNED_BYTE, mask.Pix[off:])
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}
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if style.Blur > 0 {
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b.offscr1.alpha = true
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b.enableTextureRenderTarget(&b.offscr1)
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b.glctx.ClearColor(0, 0, 0, 0)
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b.glctx.Clear(gl.COLOR_BUFFER_BIT | gl.STENCIL_BUFFER_BIT)
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}
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b.glctx.StencilFunc(gl.EQUAL, 0, 0xFF)
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b.glctx.BindBuffer(gl.ARRAY_BUFFER, b.buf)
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vertex, alphaTexCoord := b.useAlphaShader(style, 1)
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b.glctx.EnableVertexAttribArray(vertex)
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b.glctx.EnableVertexAttribArray(alphaTexCoord)
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tw := float64(w) / alphaTexSize
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th := float64(h) / alphaTexSize
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var buf [16]float32
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data := buf[:0]
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for _, pt := range pts {
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data = append(data, float32(pt[0]), float32(pt[1]))
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}
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data = append(data, 0, 1, 0, float32(1-th), float32(tw), float32(1-th), float32(tw), 1)
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b.glctx.BufferData(gl.ARRAY_BUFFER, byteSlice(unsafe.Pointer(&data[0]), len(data)*4), gl.STREAM_DRAW)
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b.glctx.VertexAttribPointer(vertex, 2, gl.FLOAT, false, 0, 0)
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b.glctx.VertexAttribPointer(alphaTexCoord, 2, gl.FLOAT, false, 0, 8*4)
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b.glctx.DrawArrays(gl.TRIANGLE_FAN, 0, 4)
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b.glctx.DisableVertexAttribArray(vertex)
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b.glctx.DisableVertexAttribArray(alphaTexCoord)
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b.glctx.ActiveTexture(gl.TEXTURE1)
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b.glctx.BindTexture(gl.TEXTURE_2D, b.alphaTex)
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b.glctx.StencilFunc(gl.ALWAYS, 0, 0xFF)
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for y := 0; y < h; y++ {
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b.glctx.TexSubImage2D(gl.TEXTURE_2D, 0, 0, alphaTexSize-1-y, w, 1, gl.ALPHA, gl.UNSIGNED_BYTE, zeroes[0:])
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}
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b.glctx.ActiveTexture(gl.TEXTURE0)
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if style.Blur > 0 {
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b.drawBlurred(style.Blur)
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}
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}
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func (b *XMobileBackend) drawBlurred(blur float64) {
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b.glctx.BlendFunc(gl.ONE, gl.ONE_MINUS_SRC_ALPHA)
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var kernel []float32
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var kernelBuf [255]float32
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var gs *gaussianShader
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if blur < 3 {
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gs = &b.gauss15r
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kernel = kernelBuf[:15]
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} else if blur < 12 {
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gs = &b.gauss63r
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kernel = kernelBuf[:63]
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} else {
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gs = &b.gauss127r
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kernel = kernelBuf[:127]
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}
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gaussianKernel(blur, kernel)
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b.offscr2.alpha = true
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b.enableTextureRenderTarget(&b.offscr2)
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b.glctx.ClearColor(0, 0, 0, 0)
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b.glctx.Clear(gl.COLOR_BUFFER_BIT | gl.STENCIL_BUFFER_BIT)
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b.glctx.StencilFunc(gl.EQUAL, 0, 0xFF)
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b.glctx.BindBuffer(gl.ARRAY_BUFFER, b.shadowBuf)
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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}
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b.glctx.BufferData(gl.ARRAY_BUFFER, byteSlice(unsafe.Pointer(&data[0]), len(data)*4), gl.STREAM_DRAW)
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b.glctx.ActiveTexture(gl.TEXTURE0)
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b.glctx.BindTexture(gl.TEXTURE_2D, b.offscr1.tex)
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b.glctx.UseProgram(gs.ID)
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b.glctx.Uniform1i(gs.Image, 0)
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b.glctx.Uniform2f(gs.CanvasSize, float32(b.fw), float32(b.fh))
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b.glctx.Uniform2f(gs.KernelScale, 1.0/float32(b.fw), 0.0)
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b.glctx.Uniform1fv(gs.Kernel, kernel)
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b.glctx.VertexAttribPointer(gs.Vertex, 2, gl.FLOAT, false, 0, 0)
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b.glctx.VertexAttribPointer(gs.TexCoord, 2, gl.FLOAT, false, 0, 8*4)
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b.glctx.EnableVertexAttribArray(gs.Vertex)
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b.glctx.EnableVertexAttribArray(gs.TexCoord)
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b.glctx.DrawArrays(gl.TRIANGLE_FAN, 0, 4)
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b.glctx.DisableVertexAttribArray(gs.Vertex)
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b.glctx.DisableVertexAttribArray(gs.TexCoord)
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b.glctx.StencilFunc(gl.ALWAYS, 0, 0xFF)
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b.disableTextureRenderTarget()
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b.glctx.StencilFunc(gl.EQUAL, 0, 0xFF)
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b.glctx.BindBuffer(gl.ARRAY_BUFFER, b.shadowBuf)
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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}
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b.glctx.BufferData(gl.ARRAY_BUFFER, byteSlice(unsafe.Pointer(&data[0]), len(data)*4), gl.STREAM_DRAW)
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b.glctx.ActiveTexture(gl.TEXTURE0)
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b.glctx.BindTexture(gl.TEXTURE_2D, b.offscr2.tex)
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b.glctx.UseProgram(gs.ID)
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b.glctx.Uniform1i(gs.Image, 0)
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b.glctx.Uniform2f(gs.CanvasSize, float32(b.fw), float32(b.fh))
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b.glctx.Uniform2f(gs.KernelScale, 0.0, 1.0/float32(b.fh))
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b.glctx.Uniform1fv(gs.Kernel, kernel)
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b.glctx.VertexAttribPointer(gs.Vertex, 2, gl.FLOAT, false, 0, 0)
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b.glctx.VertexAttribPointer(gs.TexCoord, 2, gl.FLOAT, false, 0, 8*4)
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b.glctx.EnableVertexAttribArray(gs.Vertex)
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b.glctx.EnableVertexAttribArray(gs.TexCoord)
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b.glctx.DrawArrays(gl.TRIANGLE_FAN, 0, 4)
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b.glctx.DisableVertexAttribArray(gs.Vertex)
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b.glctx.DisableVertexAttribArray(gs.TexCoord)
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b.glctx.StencilFunc(gl.ALWAYS, 0, 0xFF)
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b.glctx.BlendFunc(gl.SRC_ALPHA, gl.ONE_MINUS_SRC_ALPHA)
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}
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func gaussianKernel(stddev float64, target []float32) {
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stddevSqr := stddev * stddev
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center := float64(len(target) / 2)
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factor := 1.0 / math.Sqrt(2*math.Pi*stddevSqr)
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for i := range target {
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x := float64(i) - center
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target[i] = float32(factor * math.Pow(math.E, -x*x/(2*stddevSqr)))
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}
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// normalizeKernel(target)
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}
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func normalizeKernel(kernel []float32) {
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var sum float32
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for _, v := range kernel {
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sum += v
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}
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factor := 1.0 / sum
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for i := range kernel {
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kernel[i] *= factor
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}
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}
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