Method DepthImageArray

vgpu/render.go:364–397

DepthImageArray returns the float values from the last GrabDepthImage call automatically handles down-sampling from multisampling.

()

// DepthImageArray returns the float values from the last GrabDepthImage call
// automatically handles down-sampling from multisampling.
func (rp *Render) DepthImageArray() ([]float32, error) {
	if rp.GrabDepth.Host == vk.NullBuffer {
		err := errors.New("DepthImageArray: No GrabDepth.Host buffer -- must call GrabDepthImage")
		if Debug {
			log.Println(err)
		}
		return nil, err
	}
	sz := rp.Format.Size
	fsz := sz.X * sz.Y
	ary := make([]float32, fsz)
	fp := (*[ByteCopyMemoryLimit]float32)(rp.GrabDepth.HostPtr)[0:fsz]
	copy(ary, fp)
	// note: you cannot specify a greater width than actual width
	// and resolving depth images GPU-side is not exactly clear:
	// https://community.khronos.org/t/how-to-resolve-multi-sampled-depth-images/7584
	// https://www.reddit.com/r/vulkan/comments/rpeywp/is_it_possible_to_resolve_a_depth_msaa_buffer/
	// furthermore, the function for resolving the multiple samples is not obvious either -- average
	// is implemented below:
	// for y := 0; y < sz.Y; y++ {
	// 	for x := 0; x < sz.X; x++ {
	// 		sum := float32(0)
	// 		for ys := 0; ys < ns2; ys++ {
	// 			for xs := 0; xs < ns2; xs++ {
	// 				si := (y*ns2+ys)*sz.X*ns2 + x*ns2 + xs
	// 				sum += fp[si]
	// 			}
	// 		}
	// 		di := y*sz.X + x
	// 		ary[di] = sum / float32(nsamp)
	// 	}
	// }
	return ary, nil
}