94 lines
2.7 KiB
Go
Executable file
94 lines
2.7 KiB
Go
Executable file
package xmobilebackend
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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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"golang.org/x/mobile/gl"
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)
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// GetImageData returns an RGBA image of the current image
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func (b *XMobileBackend) 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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if len(b.imageBuf) < w*h*3 {
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b.imageBuf = make([]byte, w*h*3)
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}
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b.glctx.ReadPixels(b.imageBuf[0:], x, y, w, h, gl.RGB, gl.UNSIGNED_BYTE)
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rgba := image.NewRGBA(image.Rect(x, y, x+w, y+h))
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bp := 0
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for cy := y; cy < y+h; cy++ {
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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 *XMobileBackend) PutImageData(img *image.RGBA, x, y int) {
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b.activate()
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b.glctx.ActiveTexture(gl.TEXTURE0)
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if b.imageBufTex.Value == 0 {
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b.imageBufTex = b.glctx.CreateTexture()
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b.glctx.BindTexture(gl.TEXTURE_2D, b.imageBufTex)
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b.glctx.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.LINEAR)
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b.glctx.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.LINEAR)
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b.glctx.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_S, gl.CLAMP_TO_EDGE)
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b.glctx.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_T, gl.CLAMP_TO_EDGE)
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} else {
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b.glctx.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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b.glctx.TexImage2D(gl.TEXTURE_2D, 0, gl.RGBA, w, h, gl.RGBA, gl.UNSIGNED_BYTE, 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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b.glctx.TexImage2D(gl.TEXTURE_2D, 0, gl.RGBA, w, h, gl.RGBA, gl.UNSIGNED_BYTE, 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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b.glctx.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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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.ir.ID)
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b.glctx.Uniform1i(b.ir.Image, 0)
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b.glctx.Uniform2f(b.ir.CanvasSize, float32(b.fw), float32(b.fh))
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b.glctx.Uniform1f(b.ir.GlobalAlpha, 1)
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b.glctx.VertexAttribPointer(b.ir.Vertex, 2, gl.FLOAT, false, 0, 0)
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b.glctx.VertexAttribPointer(b.ir.TexCoord, 2, gl.FLOAT, false, 0, 8*4)
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b.glctx.EnableVertexAttribArray(b.ir.Vertex)
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b.glctx.EnableVertexAttribArray(b.ir.TexCoord)
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b.glctx.DrawArrays(gl.TRIANGLE_FAN, 0, 4)
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b.glctx.DisableVertexAttribArray(b.ir.Vertex)
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b.glctx.DisableVertexAttribArray(b.ir.TexCoord)
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}
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