Implements #133 point alignment

Further work to be done:

• switch to depth ray cast correspondences
• use normals etc in correspondences

components/renderers/cpp/src/splat_render.cpp

@@ -23,6 +23,7 @@ void Splatter::renderChannel(
 					ftl::render::SplatParams &params, ftl::rgbd::Frame &out,
 					const Channel &channel, cudaStream_t stream)
 {
+	if (channel == Channel::None) return;
 	cv::cuda::Stream cvstream = cv::cuda::StreamAccessor::wrapStream(stream);
 	temp_.get<GpuMat>(Channel::Depth).setTo(cv::Scalar(0x7FFFFFFF), cvstream);
 	temp_.get<GpuMat>(Channel::Depth2).setTo(cv::Scalar(0x7FFFFFFF), cvstream);
@@ -211,7 +212,7 @@ bool Splatter::render(ftl::rgbd::VirtualSource *src, ftl::rgbd::Frame &out, cuda
 		out.create<GpuMat>(Channel::Right, Format<uchar4>(camera.width, camera.height));
 		out.get<GpuMat>(Channel::Right).setTo(cv::Scalar(76,76,76), cvstream);
 		renderChannel(params, out, Channel::Right, stream);
-	} else {
+	} else if (chan != Channel::None) {
 		if (ftl::rgbd::isFloatChannel(chan)) {
 			out.create<GpuMat>(chan, Format<float>(camera.width, camera.height));
 			out.get<GpuMat>(chan).setTo(cv::Scalar(0.0f), cvstream);