/**
* Initialize the RHI for this rendering resource
*/
void InitRHI() override
{
const int32 NumVerts = 8;
TResourceArray<FVector4, VERTEXBUFFER_ALIGNMENT> Verts;
Verts.SetNumUninitialized(NumVerts);
for (uint32 Z = 0; Z < 2; Z++)
{
for (uint32 Y = 0; Y < 2; Y++)
{
for (uint32 X = 0; X < 2; X++)
{
const FVector4 Vertex = FVector4(
(X ? -1 : 1),
(Y ? -1 : 1),
(Z ? -1 : 1),
1.0f
);
Verts[GetCubeVertexIndex(X, Y, Z)] = Vertex;
}
}
}
uint32 Size = Verts.GetResourceDataSize();
// Create vertex buffer. Fill buffer with initial data upon creation
FRHIResourceCreateInfo CreateInfo(&Verts);
VertexBufferRHI = RHICreateVertexBuffer(Size, BUF_Static, CreateInfo);
}
static void IssueProjectedShadowOcclusionQuery(FRHICommandListImmediate& RHICmdList, FViewInfo& View, const FProjectedShadowInfo& ProjectedShadowInfo, FOcclusionQueryVS* VertexShader, int32 NumBufferedFrames)
{
FSceneViewState* ViewState = (FSceneViewState*)View.State;
const uint32 QueryIndex = FOcclusionQueryHelpers::GetQueryIssueIndex(ViewState->PendingPrevFrameNumber, NumBufferedFrames);
FSceneViewState::ShadowKeyOcclusionQueryMap& ShadowOcclusionQueryMap = ViewState->ShadowOcclusionQueryMaps[QueryIndex];
// The shadow transforms and view transforms are relative to different origins, so the world coordinates need to
// be translated.
const FVector4 PreShadowToPreViewTranslation(View.ViewMatrices.PreViewTranslation - ProjectedShadowInfo.PreShadowTranslation,0);
// If the shadow frustum is farther from the view origin than the near clipping plane,
// it can't intersect the near clipping plane.
const bool bIntersectsNearClippingPlane = ProjectedShadowInfo.ReceiverFrustum.IntersectSphere(
View.ViewMatrices.ViewOrigin + ProjectedShadowInfo.PreShadowTranslation,
View.NearClippingDistance * FMath::Sqrt(3.0f)
);
if( !bIntersectsNearClippingPlane )
{
// Allocate an occlusion query for the primitive from the occlusion query pool.
const FRenderQueryRHIRef ShadowOcclusionQuery = ViewState->OcclusionQueryPool.AllocateQuery();
VertexShader->SetParameters(RHICmdList, View);
// Draw the primitive's bounding box, using the occlusion query.
RHICmdList.BeginRenderQuery(ShadowOcclusionQuery);
void* VerticesPtr;
void* IndicesPtr;
// preallocate memory to fill out with vertices and indices
RHICmdList.BeginDrawIndexedPrimitiveUP(PT_TriangleList, 12, 8, sizeof(FVector), VerticesPtr, 0, NUM_CUBE_VERTICES, sizeof(uint16), IndicesPtr);
FVector* Vertices = (FVector*)VerticesPtr;
uint16* Indices = (uint16*)IndicesPtr;
// Generate vertices for the shadow's frustum.
for(uint32 Z = 0;Z < 2;Z++)
{
for(uint32 Y = 0;Y < 2;Y++)
{
for(uint32 X = 0;X < 2;X++)
{
const FVector4 UnprojectedVertex = ProjectedShadowInfo.InvReceiverMatrix.TransformFVector4(
FVector4(
(X ? -1.0f : 1.0f),
(Y ? -1.0f : 1.0f),
(Z ? 1.0f : 0.0f),
1.0f
)
);
const FVector ProjectedVertex = UnprojectedVertex / UnprojectedVertex.W + PreShadowToPreViewTranslation;
Vertices[GetCubeVertexIndex(X,Y,Z)] = ProjectedVertex;
}
}
}
// we just copy the indices right in
FMemory::Memcpy(Indices, GCubeIndices, sizeof(GCubeIndices));
FSceneViewState::FProjectedShadowKey Key(ProjectedShadowInfo);
checkSlow(ShadowOcclusionQueryMap.Find(Key) == NULL);
ShadowOcclusionQueryMap.Add(Key, ShadowOcclusionQuery);
RHICmdList.EndDrawIndexedPrimitiveUP();
RHICmdList.EndRenderQuery(ShadowOcclusionQuery);
}
}
