// TODO: do this for all build targets, not just linux (x11 and Android)? If
// so, should package gl instead of this package call RegisterFilter??
//
// TODO: does Android need this?? It seems to work without it (Nexus 7,
// KitKat). If only x11 needs this, should we move this to x11.go??
func registerGLViewportFilter() {
RegisterFilter(func(e interface{}) interface{} {
if e, ok := e.(size.Event); ok {
gl.Viewport(0, 0, e.WidthPx, e.HeightPx)
}
return e
})
}
func TestImage(t *testing.T) {
done := make(chan error)
defer close(done)
go func() {
runtime.LockOSThread()
ctx, err := createContext()
done <- err
for {
select {
case <-gl.WorkAvailable:
gl.DoWork()
case <-done:
ctx.destroy()
return
}
}
}()
if err := <-done; err != nil {
t.Fatalf("cannot create GL context: %v", err)
}
start()
defer stop()
// GL testing strategy:
// 1. Create an offscreen framebuffer object.
// 2. Configure framebuffer to render to a GL texture.
// 3. Run test code: use glimage to draw testdata.
// 4. Copy GL texture back into system memory.
// 5. Compare to a pre-computed image.
f, err := os.Open("../../../testdata/testpattern.png")
if err != nil {
t.Fatal(err)
}
defer f.Close()
src, _, err := image.Decode(f)
if err != nil {
t.Fatal(err)
}
const (
pixW = 100
pixH = 100
ptW = geom.Pt(50)
ptH = geom.Pt(50)
)
sz := size.Event{
WidthPx: pixW,
HeightPx: pixH,
WidthPt: ptW,
HeightPt: ptH,
PixelsPerPt: float32(pixW) / float32(ptW),
}
fBuf := gl.CreateFramebuffer()
gl.BindFramebuffer(gl.FRAMEBUFFER, fBuf)
colorBuf := gl.CreateRenderbuffer()
gl.BindRenderbuffer(gl.RENDERBUFFER, colorBuf)
// https://www.khronos.org/opengles/sdk/docs/man/xhtml/glRenderbufferStorage.xml
// says that the internalFormat "must be one of the following symbolic constants:
// GL_RGBA4, GL_RGB565, GL_RGB5_A1, GL_DEPTH_COMPONENT16, or GL_STENCIL_INDEX8".
gl.RenderbufferStorage(gl.RENDERBUFFER, gl.RGB565, pixW, pixH)
gl.FramebufferRenderbuffer(gl.FRAMEBUFFER, gl.COLOR_ATTACHMENT0, gl.RENDERBUFFER, colorBuf)
if status := gl.CheckFramebufferStatus(gl.FRAMEBUFFER); status != gl.FRAMEBUFFER_COMPLETE {
t.Fatalf("framebuffer create failed: %v", status)
}
allocs := testing.AllocsPerRun(100, func() {
gl.ClearColor(0, 0, 1, 1) // blue
})
if allocs != 0 {
t.Errorf("unexpected allocations from calling gl.ClearColor: %f", allocs)
}
gl.Clear(gl.COLOR_BUFFER_BIT)
gl.Viewport(0, 0, pixW, pixH)
m := NewImage(src.Bounds().Dx(), src.Bounds().Dy())
b := m.RGBA.Bounds()
draw.Draw(m.RGBA, b, src, src.Bounds().Min, draw.Src)
m.Upload()
b.Min.X += 10
b.Max.Y /= 2
// All-integer right-angled triangles offsetting the
// box: 24-32-40, 12-16-20.
ptTopLeft := geom.Point{0, 24}
ptTopRight := geom.Point{32, 0}
ptBottomLeft := geom.Point{12, 24 + 16}
ptBottomRight := geom.Point{12 + 32, 16}
m.Draw(sz, ptTopLeft, ptTopRight, ptBottomLeft, b)
// For unknown reasons, a windowless OpenGL context renders upside-
// down. That is, a quad covering the initial viewport spans:
//
// (-1, -1) ( 1, -1)
// (-1, 1) ( 1, 1)
//
// To avoid modifying live code for tests, we flip the rows
// recovered from the renderbuffer. We are not the first:
//
// http://lists.apple.com/archives/mac-opengl/2010/Jun/msg00080.html
got := image.NewRGBA(image.Rect(0, 0, pixW, pixH))
upsideDownPix := make([]byte, len(got.Pix))
gl.ReadPixels(upsideDownPix, 0, 0, pixW, pixH, gl.RGBA, gl.UNSIGNED_BYTE)
for y := 0; y < pixH; y++ {
i0 := (pixH - 1 - y) * got.Stride
i1 := i0 + pixW*4
copy(got.Pix[y*got.Stride:], upsideDownPix[i0:i1])
}
drawCross(got, 0, 0)
drawCross(got, int(ptTopLeft.X.Px(sz.PixelsPerPt)), int(ptTopLeft.Y.Px(sz.PixelsPerPt)))
drawCross(got, int(ptBottomRight.X.Px(sz.PixelsPerPt)), int(ptBottomRight.Y.Px(sz.PixelsPerPt)))
drawCross(got, pixW-1, pixH-1)
const wantPath = "../../../testdata/testpattern-window.png"
f, err = os.Open(wantPath)
if err != nil {
t.Fatal(err)
}
defer f.Close()
wantSrc, _, err := image.Decode(f)
if err != nil {
t.Fatal(err)
}
want, ok := wantSrc.(*image.RGBA)
if !ok {
b := wantSrc.Bounds()
want = image.NewRGBA(b)
draw.Draw(want, b, wantSrc, b.Min, draw.Src)
}
if !imageEq(got, want) {
// Write out the image we got.
f, err = ioutil.TempFile("", "testpattern-window-got")
if err != nil {
t.Fatal(err)
}
f.Close()
gotPath := f.Name() + ".png"
f, err = os.Create(gotPath)
if err != nil {
t.Fatal(err)
}
if err := png.Encode(f, got); err != nil {
t.Fatal(err)
}
if err := f.Close(); err != nil {
t.Fatal(err)
}
t.Errorf("got\n%s\nwant\n%s", gotPath, wantPath)
}
}