327 lines
10 KiB
Go
Executable file
327 lines
10 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]backendbase.Vec) {
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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.shd.ID)
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b.glctx.Uniform2f(b.shd.CanvasSize, float32(b.fw), float32(b.fh))
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b.glctx.UniformMatrix3fv(b.shd.Matrix, mat3identity[:])
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b.glctx.Uniform4f(b.shd.Color, 0, 0, 0, 0)
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b.glctx.Uniform1f(b.shd.GlobalAlpha, 1)
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b.glctx.Uniform1i(b.shd.UseAlphaTex, 0)
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b.glctx.Uniform1i(b.shd.Func, shdFuncSolid)
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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.shd.Vertex, 2, gl.FLOAT, false, 0, 0)
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b.glctx.EnableVertexAttribArray(b.shd.Vertex)
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b.glctx.DrawArrays(gl.TRIANGLE_FAN, 0, 4)
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b.glctx.DisableVertexAttribArray(b.shd.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 extent(pts []backendbase.Vec) (min, max backendbase.Vec) {
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max[0] = -math.MaxFloat64
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max[1] = -math.MaxFloat64
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min[0] = math.MaxFloat64
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min[1] = math.MaxFloat64
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for _, v := range pts {
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min[0] = math.Min(min[0], v[0])
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min[1] = math.Min(min[1], v[1])
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max[0] = math.Max(max[0], v[0])
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max[1] = math.Max(max[1], v[1])
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}
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return
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}
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func (b *XMobileBackend) Fill(style *backendbase.FillStyle, pts []backendbase.Vec, tf backendbase.Mat, canOverlap bool) {
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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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min, max := extent(pts)
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b.ptsBuf = append(b.ptsBuf,
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float32(min[0]), float32(min[1]),
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float32(min[0]), float32(max[1]),
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float32(max[0]), float32(max[1]),
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float32(max[0]), float32(min[1]))
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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 !canOverlap || style.Color.A >= 255 {
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vertex, _ := b.useShader(style, mat3(tf), false, 0)
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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.shd.ID)
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b.glctx.Uniform4f(b.shd.Color, 0, 0, 0, 0)
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b.glctx.Uniform2f(b.shd.CanvasSize, float32(b.fw), float32(b.fh))
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m3 := mat3(tf)
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b.glctx.UniformMatrix3fv(b.shd.Matrix, m3[:])
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b.glctx.Uniform1f(b.shd.GlobalAlpha, 1)
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b.glctx.Uniform1i(b.shd.UseAlphaTex, 0)
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b.glctx.Uniform1i(b.shd.Func, shdFuncSolid)
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b.glctx.EnableVertexAttribArray(b.shd.Vertex)
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b.glctx.VertexAttribPointer(b.shd.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.shd.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, mat3identity, false, 0)
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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(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, min, max)
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}
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}
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func (b *XMobileBackend) FillImageMask(style *backendbase.FillStyle, mask *image.Alpha, pts [4]backendbase.Vec) {
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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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b.glctx.TexSubImage2D(gl.TEXTURE_2D, 0, 0, 0, mask.Stride, h, gl.ALPHA, gl.UNSIGNED_BYTE, mask.Pix[0:])
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if w < alphaTexSize {
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b.glctx.TexSubImage2D(gl.TEXTURE_2D, 0, w, 0, 1, h, gl.ALPHA, gl.UNSIGNED_BYTE, zeroes[0:])
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}
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if h < alphaTexSize {
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b.glctx.TexSubImage2D(gl.TEXTURE_2D, 0, 0, h, w, 1, gl.ALPHA, gl.UNSIGNED_BYTE, zeroes[0:])
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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.useShader(style, mat3identity, true, 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, 0, 0, float32(th), float32(tw), float32(th), float32(tw), 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.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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b.glctx.ActiveTexture(gl.TEXTURE0)
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if style.Blur > 0 {
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min, max := extent(pts[:])
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b.drawBlurred(style.Blur, min, max)
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}
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}
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func (b *XMobileBackend) drawBlurred(size float64, min, max backendbase.Vec) {
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b.offscr1.alpha = true
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b.offscr2.alpha = true
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// calculate box blur size
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fsize := math.Max(1, math.Floor(size))
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sizea := int(fsize)
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sizeb := sizea
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sizec := sizea
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if size-fsize > 0.333333333 {
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sizeb++
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}
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if size-fsize > 0.666666666 {
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sizec++
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}
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min[0] -= fsize * 3
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min[1] -= fsize * 3
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max[0] += fsize * 3
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max[1] += fsize * 3
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min[0] = math.Max(0.0, math.Min(b.fw, min[0]))
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min[1] = math.Max(0.0, math.Min(b.fh, min[1]))
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max[0] = math.Max(0.0, math.Min(b.fw, max[0]))
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max[1] = math.Max(0.0, math.Min(b.fh, max[1]))
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b.glctx.BindBuffer(gl.ARRAY_BUFFER, b.shadowBuf)
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data := [16]float32{
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float32(min[0]), float32(min[1]),
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float32(min[0]), float32(max[1]),
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float32(max[0]), float32(max[1]),
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float32(max[0]), float32(min[1]),
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float32(min[0] / b.fw), 1 - float32(min[1]/b.fh),
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float32(min[0] / b.fw), 1 - float32(max[1]/b.fh),
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float32(max[0] / b.fw), 1 - float32(max[1]/b.fh),
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float32(max[0] / b.fw), 1 - float32(min[1]/b.fh),
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}
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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.UseProgram(b.shd.ID)
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b.glctx.Uniform1i(b.shd.Image, 0)
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b.glctx.Uniform2f(b.shd.CanvasSize, float32(b.fw), float32(b.fh))
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b.glctx.UniformMatrix3fv(b.shd.Matrix, mat3identity[:])
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b.glctx.Uniform1i(b.shd.UseAlphaTex, 0)
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b.glctx.Uniform1i(b.shd.Func, shdFuncBoxBlur)
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b.glctx.VertexAttribPointer(b.shd.Vertex, 2, gl.FLOAT, false, 0, 0)
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b.glctx.VertexAttribPointer(b.shd.TexCoord, 2, gl.FLOAT, false, 0, 8*4)
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b.glctx.EnableVertexAttribArray(b.shd.Vertex)
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b.glctx.EnableVertexAttribArray(b.shd.TexCoord)
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b.glctx.Disable(gl.BLEND)
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b.glctx.ActiveTexture(gl.TEXTURE0)
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b.glctx.ClearColor(0, 0, 0, 0)
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b.enableTextureRenderTarget(&b.offscr2)
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b.glctx.BindTexture(gl.TEXTURE_2D, b.offscr1.tex)
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b.glctx.Clear(gl.COLOR_BUFFER_BIT | gl.STENCIL_BUFFER_BIT)
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b.box3(sizea, 0, false)
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b.enableTextureRenderTarget(&b.offscr1)
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b.glctx.BindTexture(gl.TEXTURE_2D, b.offscr2.tex)
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b.box3(sizeb, -0.5, false)
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b.enableTextureRenderTarget(&b.offscr2)
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b.glctx.BindTexture(gl.TEXTURE_2D, b.offscr1.tex)
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b.box3(sizec, 0, false)
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b.enableTextureRenderTarget(&b.offscr1)
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b.glctx.BindTexture(gl.TEXTURE_2D, b.offscr2.tex)
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b.box3(sizea, 0, true)
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b.enableTextureRenderTarget(&b.offscr2)
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b.glctx.BindTexture(gl.TEXTURE_2D, b.offscr1.tex)
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b.box3(sizeb, -0.5, true)
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b.glctx.Enable(gl.BLEND)
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b.glctx.BlendFunc(gl.ONE, gl.ONE_MINUS_SRC_ALPHA)
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b.disableTextureRenderTarget()
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b.glctx.BindTexture(gl.TEXTURE_2D, b.offscr2.tex)
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b.box3(sizec, 0, true)
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b.glctx.DisableVertexAttribArray(b.shd.Vertex)
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b.glctx.DisableVertexAttribArray(b.shd.TexCoord)
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b.glctx.BlendFunc(gl.SRC_ALPHA, gl.ONE_MINUS_SRC_ALPHA)
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}
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func (b *XMobileBackend) box3(size int, offset float32, vertical bool) {
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b.glctx.Uniform1i(b.shd.BoxSize, size)
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if vertical {
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b.glctx.Uniform1i(b.shd.BoxVertical, 1)
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b.glctx.Uniform1f(b.shd.BoxScale, 1/float32(b.fh))
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} else {
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b.glctx.Uniform1i(b.shd.BoxVertical, 0)
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b.glctx.Uniform1f(b.shd.BoxScale, 1/float32(b.fw))
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}
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b.glctx.Uniform1f(b.shd.BoxOffset, offset)
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b.glctx.DrawArrays(gl.TRIANGLE_FAN, 0, 4)
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}
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