Fix issue with the resolve of motion vectors (#421)

Author: FrancescoC-unity

com.unity.render-pipelines.high-definition/Runtime/Material/SharedRTManager.cs

@@ -382,7 +382,7 @@ public void ResolveMotionVectorTexture(CommandBuffer cmd, HDCamera hdCamera)
             {
                 using (new ProfilingScope(cmd, ProfilingSampler.Get(HDProfileId.ResolveMSAAMotionVector)))
                 {
-                    CoreUtils.SetRenderTarget(cmd, m_MotionVectorsRT, m_CameraDepthStencilBuffer);
+                    CoreUtils.SetRenderTarget(cmd, m_MotionVectorsRT);
                     Shader.SetGlobalTexture(HDShaderIDs._MotionVectorTextureMS, m_MotionVectorsMSAART);
                     cmd.DrawProcedural(Matrix4x4.identity, m_MotionVectorResolve, SampleCountToPassIndex(m_MSAASamples), MeshTopology.Triangles, 3, 1);
                 }

com.unity.render-pipelines.high-definition/Runtime/RenderPipeline/HDRenderPipeline.cs

@@ -2515,6 +2515,7 @@ void Callback(CommandBuffer c, HDCamera cam)
                 if (hdCamera.frameSettings.IsEnabled(FrameSettingsField.TransparentsWriteMotionVector))
                 {
                     m_SharedRTManager.ResolveMotionVectorTexture(cmd, hdCamera);
+                    cmd.SetGlobalTexture(HDShaderIDs._CameraMotionVectorsTexture, m_SharedRTManager.GetMotionVectorsBuffer());
                 }
 
                 // We push the motion vector debug texture here as transparent object can overwrite the motion vector texture content.