Doing frustum culling on 10.000 objects it takes about 0.85ms...is that slow/fast ?
I'm using AABBs to frustum cull my objects.
See code here:
bool RendererD3D11::FrustumCull(SceneEntityDescription* entity,
XMFLOAT4* frustumPlanes)
{
// If there even was a rejection last time
if(entity->lastRejectedFrustumPlane != 999999)
{
// Check last rejected planeId first
XMVECTOR planeNormal = XMVectorSet(frustumPlanes[entity->lastRejectedFrustumPlane].x, frustumPlanes[entity->lastRejectedFrustumPlane].y,
frustumPlanes[entity->lastRejectedFrustumPlane].z, 0.0f);
float planeConstant = frustumPlanes[entity->lastRejectedFrustumPlane].w;
// Check each axis (x, y, z) to get the AABB vertex furthest away from the direction
// the plane is facing (plane normal)
XMFLOAT3 axisVert;
XMFLOAT3 aabb_min = this->contentManager->GetPrimitiveFromPool(entity->ID)->GetBoundingVolume()->Min();
XMFLOAT3 aabb_max = this->contentManager->GetPrimitiveFromPool(entity->ID)->GetBoundingVolume()->Max();
XMFLOAT3 objPos = entity->worldPosition;
// x-axis
if(frustumPlanes[entity->lastRejectedFrustumPlane].x < 0.0f)
{
axisVert.x = aabb_min.x + objPos.x; // min x + obj position's x
}
else
{
axisVert.x = aabb_max.x + objPos.x; // max x + obj position's x
}
// y-axis
if(frustumPlanes[entity->lastRejectedFrustumPlane].y < 0.0f)
{
axisVert.y = aabb_min.y + objPos.y; // min y + obj position's y
}
else
{
axisVert.y = aabb_max.y + objPos.y; // max y + obj position's y
}
// z-axis
if(frustumPlanes[entity->lastRejectedFrustumPlane].z < 0.0f)
{
axisVert.z = aabb_min.z + objPos.z; // min z + obj position's z
}
else
{
axisVert.z = aabb_max.z + objPos.z; // min z + obj position's z
}
// Now we get the signed distance from the AABB's vertex that's furthest down the frustum planes normal,
// and if the signed distance is negative, then the entire bounding box is behind the frustum plane, which means
// that it should be culled
if(XMVectorGetX(XMVector3Dot(planeNormal, XMLoadFloat3(&axisVert))) + planeConstant < 0.0f)
{
return true;
}
}
// Loop through each frustum plane
for(int planeID = 0; planeID < 6; ++planeID)
{
if(entity->lastRejectedFrustumPlane != 999999)
{
if(planeID == entity->lastRejectedFrustumPlane)
{
// skip last rejected frustum plane since we've checked it before this loop
continue;
}
}
XMVECTOR planeNormal = XMVectorSet(frustumPlanes[planeID].x, frustumPlanes[planeID].y,
frustumPlanes[planeID].z, 0.0f);
float planeConstant = frustumPlanes[planeID].w;
// Check each axis (x, y, z) to get the AABB vertex furthest away from the direction
// the plane is facing (plane normal)
XMFLOAT3 axisVert;
XMFLOAT3 aabb_min = this->contentManager->GetPrimitiveFromPool(entity->ID)->GetBoundingVolume()->Min();
XMFLOAT3 aabb_max = this->contentManager->GetPrimitiveFromPool(entity->ID)->GetBoundingVolume()->Max();
XMFLOAT3 objPos = entity->worldPosition;
// x-axis
if(frustumPlanes[planeID].x < 0.0f)
{
axisVert.x = aabb_min.x + objPos.x; // min x + obj position's x
}
else
{
axisVert.x = aabb_max.x + objPos.x; // max x + obj position's x
}
// y-axis
if(frustumPlanes[planeID].y < 0.0f)
{
axisVert.y = aabb_min.y + objPos.y; // min y + obj position's y
}
else
{
axisVert.y = aabb_max.y + objPos.y; // max y + obj position's y
}
// z-axis
if(frustumPlanes[planeID].z < 0.0f)
{
axisVert.z = aabb_min.z + objPos.z; // min z + obj position's z
}
else
{
axisVert.z = aabb_max.z + objPos.z; // min z + obj position's z
}
// Now we get the signed distance from the AABB's vertex that's furthest down the frustum planes normal,
// and if the signed distance is negative, then the entire bounding box is behind the frustum plane, which means
// that it should be culled
if(XMVectorGetX(XMVector3Dot(planeNormal, XMLoadFloat3(&axisVert))) + planeConstant < 0.0f)
{
entity->lastRejectedFrustumPlane = planeID; // store rejected frustum plane ID for the next frames
return true;
}
}
return false;
}
Keep in mind these 10.000 objects are all inside the view frustum so they'll all go through all 6 planes and pass (worst case scenario I know).
I've commented out the draw call itself so the rendering itself has no influence on these numbers.
