102 lines
2.9 KiB
Go
102 lines
2.9 KiB
Go
package goglbackend
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import (
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"image"
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"image/color"
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"unsafe"
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"github.com/tfriedel6/canvas/backend/goglbackend/gl"
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)
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// GetImageData returns an RGBA image of the current image
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func (b *GoGLBackend) GetImageData(x, y, w, h int) *image.RGBA {
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b.activate()
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if x < 0 {
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w += x
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x = 0
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}
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if y < 0 {
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h += y
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y = 0
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}
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if w > b.w {
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w = b.w
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}
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if h > b.h {
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h = b.h
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}
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var vp [4]int32
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gl.GetIntegerv(gl.VIEWPORT, &vp[0])
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size := int(vp[2] * vp[3] * 3)
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if len(b.imageBuf) < size {
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b.imageBuf = make([]byte, size)
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}
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gl.ReadPixels(vp[0], vp[1], vp[2], vp[3], gl.RGB, gl.UNSIGNED_BYTE, gl.Ptr(&b.imageBuf[0]))
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rgba := image.NewRGBA(image.Rect(x, y, x+w, y+h))
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for cy := y; cy < y+h; cy++ {
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bp := (int(vp[3])-h+cy)*int(vp[2])*3 + x*3
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for cx := x; cx < x+w; cx++ {
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rgba.SetRGBA(cx, y+h-1-cy, color.RGBA{R: b.imageBuf[bp], G: b.imageBuf[bp+1], B: b.imageBuf[bp+2], A: 255})
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bp += 3
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}
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}
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return rgba
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}
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// PutImageData puts the given image at the given x/y coordinates
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func (b *GoGLBackend) PutImageData(img *image.RGBA, x, y int) {
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b.activate()
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gl.ActiveTexture(gl.TEXTURE0)
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if b.imageBufTex == 0 {
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gl.GenTextures(1, &b.imageBufTex)
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gl.BindTexture(gl.TEXTURE_2D, b.imageBufTex)
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gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.LINEAR)
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gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.LINEAR)
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gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_S, gl.CLAMP_TO_EDGE)
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gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_T, gl.CLAMP_TO_EDGE)
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} else {
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gl.BindTexture(gl.TEXTURE_2D, b.imageBufTex)
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}
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w, h := img.Bounds().Dx(), img.Bounds().Dy()
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if img.Stride == img.Bounds().Dx()*4 {
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gl.TexImage2D(gl.TEXTURE_2D, 0, gl.RGBA, int32(w), int32(h), 0, gl.RGBA, gl.UNSIGNED_BYTE, gl.Ptr(&img.Pix[0]))
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} else {
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data := make([]uint8, 0, w*h*4)
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for cy := 0; cy < h; cy++ {
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start := cy * img.Stride
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end := start + w*4
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data = append(data, img.Pix[start:end]...)
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}
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gl.TexImage2D(gl.TEXTURE_2D, 0, gl.RGBA, int32(w), int32(h), 0, gl.RGBA, gl.UNSIGNED_BYTE, gl.Ptr(&data[0]))
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}
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dx, dy := float32(x), float32(y)
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dw, dh := float32(w), float32(h)
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gl.BindBuffer(gl.ARRAY_BUFFER, b.buf)
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data := [16]float32{dx, dy, dx + dw, dy, dx + dw, dy + dh, dx, dy + dh,
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0, 0, 1, 0, 1, 1, 0, 1}
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gl.BufferData(gl.ARRAY_BUFFER, len(data)*4, unsafe.Pointer(&data[0]), gl.STREAM_DRAW)
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gl.UseProgram(b.shd.ID)
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gl.Uniform1i(b.shd.Image, 0)
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gl.Uniform2f(b.shd.CanvasSize, float32(b.fw), float32(b.fh))
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gl.UniformMatrix3fv(b.shd.Matrix, 1, false, &mat3identity[0])
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gl.Uniform1f(b.shd.GlobalAlpha, 1)
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gl.Uniform1i(b.shd.UseAlphaTex, 0)
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gl.Uniform1i(b.shd.Func, shdFuncImage)
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gl.VertexAttribPointer(b.shd.Vertex, 2, gl.FLOAT, false, 0, nil)
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gl.VertexAttribPointer(b.shd.TexCoord, 2, gl.FLOAT, false, 0, gl.PtrOffset(8*4))
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gl.EnableVertexAttribArray(b.shd.Vertex)
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gl.EnableVertexAttribArray(b.shd.TexCoord)
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gl.DrawArrays(gl.TRIANGLE_FAN, 0, 4)
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gl.DisableVertexAttribArray(b.shd.Vertex)
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gl.DisableVertexAttribArray(b.shd.TexCoord)
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}
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