Method DevGoImageCopy

vgpu/image.go:460–487

DevGoImageCopy sets the given image.RGBA standard Go image to a copy of the HostOnly Device memory representation, re-sizing the pixel memory as needed. If the image pixels are sufficiently sized, no memory allocation occurs. Only works if ImageOnHostOnly, and works best if Format is default vk.Form

(rgba *image.RGBA)

// vk.FormatR8g8b8a8Srgb (strongly recommended in any case).
// If format is vk.FormatR8g8b8a8Unorm, it will be converted to srgb.
func (im *Image) DevGoImageCopy(rgba *image.RGBA) error {
	if !im.HasFlag(ImageOnHostOnly) || im.Mem == vk.NullDeviceMemory {
		return fmt.Errorf("vgpu.Image DevGoImage: Image not available because device Image is not HostOnly, or Mem is nil: %s", im.Name)
	}
	if !im.Format.IsStdRGBA() && !im.Format.IsRGBAUnorm() {
		return fmt.Errorf("vgpu.Image DevGoImage: Device image is not standard RGBA or Unorm format: %s", im.Format.String())
	}

	size := im.Format.LayerByteSize()
	subrec := vk.ImageSubresource{}
	subrec.AspectMask = vk.ImageAspectFlags(vk.ImageAspectColorBit)
	sublay := vk.SubresourceLayout{}
	vk.GetImageSubresourceLayout(im.Dev, im.Image, &subrec, &sublay)
	offset := int(sublay.Offset)
	ptr := MapMemoryAll(im.Dev, im.Mem)
	pix := (*[ByteCopyMemoryLimit]byte)(ptr)[offset : size+offset]

	rgba.Pix = slicesx.SetLength(rgba.Pix, size)
	copy(rgba.Pix, pix)
	vk.UnmapMemory(im.Dev, im.Mem)
	if im.Format.IsRGBAUnorm() {
		fmt.Println("converting to linear")
		SetImageSRGBFromLinear(rgba)
	}
	rgba.Stride = im.Format.Stride()
	rgba.Rect = image.Rect(0, 0, im.Format.Size.X, im.Format.Size.Y)
	return nil
}

// UnmapDev calls UnmapMemory on the mapped memory for this image,
// set by MapMemoryAll.  This must be called after image is used in