make sure the esitmated vertex alignment is PoT

Author: devsh

include/nbl/video/IGPUAccelerationStructure.h

@@ -228,7 +228,7 @@ class IGPUBottomLevelAccelerationStructure : public asset::IBottomLevelAccelerat
 
 					const size_t vertexSize = asset::getTexelOrBlockBytesize(geometry.vertexFormat);
 					// TODO: improve in line with the spec https://registry.khronos.org/vulkan/specs/1.3-extensions/html/vkspec.html#VUID-vkCmdBuildAccelerationStructuresKHR-pInfos-03711
-					const size_t vertexAlignment = core::max(vertexSize/4u,1ull);
+					const size_t vertexAlignment = core::max(core::roundDownToPoT(vertexSize/asset::getFormatChannelCount(geometry.vertexFormat)),1ull);
 					// https://registry.khronos.org/vulkan/specs/1.3-extensions/html/vkspec.html#VUID-VkAccelerationStructureGeometryTrianglesDataKHR-vertexStride-03735
 					if (!core::is_aligned_to(geometry.vertexStride,vertexAlignment))
 						return false;