217 lines
6.1 KiB
Go
217 lines
6.1 KiB
Go
package goglbackend
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import (
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"math"
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"unsafe"
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"github.com/go-gl/gl/v3.2-core/gl"
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"github.com/tfriedel6/canvas/backend/backendbase"
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)
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// ClearRect sets the color of the rectangle to transparent black
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func (b *GoGLBackend) ClearRect(x, y, w, h int) {
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gl.Scissor(int32(x), int32(b.h-y-h), int32(w), int32(h))
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gl.ClearColor(0, 0, 0, 0)
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gl.Clear(gl.COLOR_BUFFER_BIT)
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// cv.applyScissor()
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}
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func (b *GoGLBackend) Clear(pts [4][2]float64) {
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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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gl.UseProgram(b.sr.ID)
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gl.Uniform2f(b.sr.CanvasSize, float32(b.fw), float32(b.fh))
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gl.Uniform4f(b.sr.Color, 0, 0, 0, 0)
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gl.Uniform1f(b.sr.GlobalAlpha, 1)
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gl.Disable(gl.BLEND)
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gl.BindBuffer(gl.ARRAY_BUFFER, b.buf)
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gl.BufferData(gl.ARRAY_BUFFER, len(data)*4, unsafe.Pointer(&data[0]), gl.STREAM_DRAW)
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gl.StencilFunc(gl.EQUAL, 0, 0xFF)
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gl.VertexAttribPointer(b.sr.Vertex, 2, gl.FLOAT, false, 0, nil)
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gl.EnableVertexAttribArray(b.sr.Vertex)
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gl.DrawArrays(gl.TRIANGLE_FAN, 0, 4)
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gl.DisableVertexAttribArray(b.sr.Vertex)
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gl.StencilFunc(gl.ALWAYS, 0, 0xFF)
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gl.Enable(gl.BLEND)
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}
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func (b *GoGLBackend) Fill(style *backendbase.FillStyle, pts [][2]float64) {
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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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gl.ClearColor(0, 0, 0, 0)
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gl.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 := uint32(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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gl.BindBuffer(gl.ARRAY_BUFFER, b.buf)
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gl.BufferData(gl.ARRAY_BUFFER, len(b.ptsBuf)*4, unsafe.Pointer(&b.ptsBuf[0]), gl.STREAM_DRAW)
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if style.Color.A >= 255 {
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vertex := b.useShader(style)
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gl.EnableVertexAttribArray(vertex)
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gl.VertexAttribPointer(vertex, 2, gl.FLOAT, false, 0, nil)
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gl.DrawArrays(mode, 4, int32(len(pts)))
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gl.DisableVertexAttribArray(vertex)
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} else {
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gl.ColorMask(false, false, false, false)
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gl.StencilFunc(gl.ALWAYS, 1, 0xFF)
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gl.StencilOp(gl.REPLACE, gl.REPLACE, gl.REPLACE)
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gl.StencilMask(0x01)
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gl.UseProgram(b.sr.ID)
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gl.Uniform4f(b.sr.Color, 0, 0, 0, 0)
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gl.Uniform2f(b.sr.CanvasSize, float32(b.fw), float32(b.fh))
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gl.EnableVertexAttribArray(b.sr.Vertex)
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gl.VertexAttribPointer(b.sr.Vertex, 2, gl.FLOAT, false, 0, nil)
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gl.DrawArrays(mode, 4, int32(len(pts)))
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gl.DisableVertexAttribArray(b.sr.Vertex)
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gl.ColorMask(true, true, true, true)
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gl.StencilFunc(gl.EQUAL, 1, 0xFF)
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vertex := b.useShader(style)
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gl.EnableVertexAttribArray(vertex)
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gl.VertexAttribPointer(vertex, 2, gl.FLOAT, false, 0, nil)
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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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gl.DrawArrays(gl.TRIANGLE_FAN, 0, 4)
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gl.DisableVertexAttribArray(vertex)
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gl.StencilOp(gl.KEEP, gl.KEEP, gl.KEEP)
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gl.StencilFunc(gl.ALWAYS, 0, 0xFF)
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gl.Clear(gl.STENCIL_BUFFER_BIT)
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gl.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 *GoGLBackend) drawBlurred(blur float64) {
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gl.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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gl.ClearColor(0, 0, 0, 0)
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gl.Clear(gl.COLOR_BUFFER_BIT | gl.STENCIL_BUFFER_BIT)
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gl.StencilFunc(gl.EQUAL, 0, 0xFF)
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gl.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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gl.BufferData(gl.ARRAY_BUFFER, len(data)*4, unsafe.Pointer(&data[0]), gl.STREAM_DRAW)
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gl.ActiveTexture(gl.TEXTURE0)
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gl.BindTexture(gl.TEXTURE_2D, b.offscr1.tex)
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gl.UseProgram(gs.ID)
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gl.Uniform1i(gs.Image, 0)
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gl.Uniform2f(gs.CanvasSize, float32(b.fw), float32(b.fh))
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gl.Uniform2f(gs.KernelScale, 1.0/float32(b.fw), 0.0)
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gl.Uniform1fv(gs.Kernel, int32(len(kernel)), &kernel[0])
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gl.VertexAttribPointer(gs.Vertex, 2, gl.FLOAT, false, 0, nil)
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gl.VertexAttribPointer(gs.TexCoord, 2, gl.FLOAT, false, 0, gl.PtrOffset(8*4))
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gl.EnableVertexAttribArray(gs.Vertex)
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gl.EnableVertexAttribArray(gs.TexCoord)
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gl.DrawArrays(gl.TRIANGLE_FAN, 0, 4)
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gl.DisableVertexAttribArray(gs.Vertex)
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gl.DisableVertexAttribArray(gs.TexCoord)
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gl.StencilFunc(gl.ALWAYS, 0, 0xFF)
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b.disableTextureRenderTarget()
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gl.StencilFunc(gl.EQUAL, 0, 0xFF)
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gl.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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gl.BufferData(gl.ARRAY_BUFFER, len(data)*4, unsafe.Pointer(&data[0]), gl.STREAM_DRAW)
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gl.ActiveTexture(gl.TEXTURE0)
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gl.BindTexture(gl.TEXTURE_2D, b.offscr2.tex)
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gl.UseProgram(gs.ID)
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gl.Uniform1i(gs.Image, 0)
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gl.Uniform2f(gs.CanvasSize, float32(b.fw), float32(b.fh))
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gl.Uniform2f(gs.KernelScale, 0.0, 1.0/float32(b.fh))
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gl.Uniform1fv(gs.Kernel, int32(len(kernel)), &kernel[0])
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gl.VertexAttribPointer(gs.Vertex, 2, gl.FLOAT, false, 0, nil)
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gl.VertexAttribPointer(gs.TexCoord, 2, gl.FLOAT, false, 0, gl.PtrOffset(8*4))
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gl.EnableVertexAttribArray(gs.Vertex)
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gl.EnableVertexAttribArray(gs.TexCoord)
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gl.DrawArrays(gl.TRIANGLE_FAN, 0, 4)
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gl.DisableVertexAttribArray(gs.Vertex)
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gl.DisableVertexAttribArray(gs.TexCoord)
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gl.StencilFunc(gl.ALWAYS, 0, 0xFF)
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gl.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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