Problem with TextureData.Updates() #489
Description
I'm using cimgui-go with a custom backend. Now I'm updating to version 1.4.0, and it seems to work until imgui wants to update the texures. The C code I'm translating from imgui_impl_opengl3.cpp is:
for (ImTextureRect& r : tex->Updates)
{
const int src_pitch = r.w * tex->BytesPerPixel;
bd->TempBuffer.resize(r.h * src_pitch);
char* out_p = bd->TempBuffer.Data;
for (int y = 0; y < r.h; y++, out_p += src_pitch)
memcpy(out_p, tex->GetPixelsAt(r.x, r.y + y), src_pitch);
IM_ASSERT(out_p == bd->TempBuffer.end());
GL_CALL(glTexSubImage2D(GL_TEXTURE_2D, 0, r.x, r.y, r.w, r.h, GL_RGBA, GL_UNSIGNED_BYTE, bd->TempBuffer.Data));
}
My translation is:
for _, r := range tex.Updates().Slice() {
srcPitch := int(r.W()) * int(tex.BytesPerPixel())
size := int(r.H()) * srcPitch
if len(renderer.tempBuffer) < size {
renderer.tempBuffer = append(renderer.tempBuffer, make([]byte, size-len(renderer.tempBuffer))...)
}
offset := 0
for y := 0; y < int(r.H()); y++ {
src := unsafe.Slice((*byte)(unsafe.Pointer(tex.PixelsAt(int32(r.X()), int32(r.Y())+int32(y)))), srcPitch)
copy(renderer.tempBuffer[offset:offset+srcPitch], src)
offset += srcPitch
}
gl.TexSubImage2D(gl.TEXTURE_2D, 0,
int32(r.X()), int32(r.Y()), int32(r.W()), int32(r.H()),
gl.RGBA, gl.UNSIGNED_BYTE, unsafe.Pointer(&renderer.tempBuffer[0]))
}
I get a fault panic on copy, which I think is due to strange rects from tex.Updates().Slice(): I get rectangles much larger than the texture or with width or height equal to 0.