RenderContextType SelectRenderContext(CoreState* state)
{
if (state->render_state->m_render_depth)
return RenderDepth(state);
else if (state->render_state->m_enable_terrain)
return RenderTerrain(state);
else if (state->render_state->m_enable_lighting)
return RenderLighting(state);
else // NO LIGHTING
return RenderSolid(state);
return RenderContextType::NoRender;
}
// Renders meshes using cascaded shadow mapping
void MeshRenderer::RenderSunShadowMap(ID3D11DeviceContext* context, const Camera& camera)
{
PIXEvent event(L"Sun Shadow Map Rendering");
const float MinDistance = reductionDepth.x;
const float MaxDistance = reductionDepth.y;
// Compute the split distances based on the partitioning mode
float CascadeSplits[4] = { 0.0f, 0.0f, 0.0f, 0.0f };
{
float lambda = 1.0f;
float nearClip = camera.NearClip();
float farClip = camera.FarClip();
float clipRange = farClip - nearClip;
float minZ = nearClip + MinDistance * clipRange;
float maxZ = nearClip + MaxDistance * clipRange;
float range = maxZ - minZ;
float ratio = maxZ / minZ;
for(uint32 i = 0; i < NumCascades; ++i)
{
float p = (i + 1) / static_cast<float>(NumCascades);
float log = minZ * std::pow(ratio, p);
float uniform = minZ + range * p;
float d = lambda * (log - uniform) + uniform;
CascadeSplits[i] = (d - nearClip) / clipRange;
}
}
Float3 c0Extents;
Float4x4 c0Matrix;
const Float3 lightDir = AppSettings::SunDirection;
// Render the meshes to each cascade
for(uint32 cascadeIdx = 0; cascadeIdx < NumCascades; ++cascadeIdx)
{
PIXEvent cascadeEvent((L"Rendering Shadow Map Cascade " + ToString(cascadeIdx)).c_str());
// Set the viewport
SetViewport(context, ShadowMapSize, ShadowMapSize);
// Set the shadow map as the depth target
ID3D11DepthStencilView* dsv = sunShadowDepthMap.DSView;
ID3D11RenderTargetView* nullRenderTargets[D3D11_SIMULTANEOUS_RENDER_TARGET_COUNT] = { NULL };
context->OMSetRenderTargets(D3D11_SIMULTANEOUS_RENDER_TARGET_COUNT, nullRenderTargets, dsv);
context->ClearDepthStencilView(dsv, D3D11_CLEAR_DEPTH|D3D11_CLEAR_STENCIL, 1.0f, 0);
// Get the 8 points of the view frustum in world space
XMVECTOR frustumCornersWS[8] =
{
XMVectorSet(-1.0f, 1.0f, 0.0f, 1.0f),
XMVectorSet( 1.0f, 1.0f, 0.0f, 1.0f),
XMVectorSet( 1.0f, -1.0f, 0.0f, 1.0f),
XMVectorSet(-1.0f, -1.0f, 0.0f, 1.0f),
XMVectorSet(-1.0f, 1.0f, 1.0f, 1.0f),
XMVectorSet( 1.0f, 1.0f, 1.0f, 1.0f),
XMVectorSet( 1.0f, -1.0f, 1.0f, 1.0f),
XMVectorSet(-1.0f, -1.0f, 1.0f, 1.0f),
};
float prevSplitDist = cascadeIdx == 0 ? MinDistance : CascadeSplits[cascadeIdx - 1];
float splitDist = CascadeSplits[cascadeIdx];
XMVECTOR det;
XMMATRIX invViewProj = XMMatrixInverse(&det, camera.ViewProjectionMatrix().ToSIMD());
for(uint32 i = 0; i < 8; ++i)
frustumCornersWS[i] = XMVector3TransformCoord(frustumCornersWS[i], invViewProj);
// Get the corners of the current cascade slice of the view frustum
for(uint32 i = 0; i < 4; ++i)
{
XMVECTOR cornerRay = XMVectorSubtract(frustumCornersWS[i + 4], frustumCornersWS[i]);
XMVECTOR nearCornerRay = XMVectorScale(cornerRay, prevSplitDist);
XMVECTOR farCornerRay = XMVectorScale(cornerRay, splitDist);
frustumCornersWS[i + 4] = XMVectorAdd(frustumCornersWS[i], farCornerRay);
frustumCornersWS[i] = XMVectorAdd(frustumCornersWS[i], nearCornerRay);
}
// Calculate the centroid of the view frustum slice
XMVECTOR frustumCenterVec = XMVectorZero();
for(uint32 i = 0; i < 8; ++i)
frustumCenterVec = XMVectorAdd(frustumCenterVec, frustumCornersWS[i]);
frustumCenterVec = XMVectorScale(frustumCenterVec, 1.0f / 8.0f);
Float3 frustumCenter = frustumCenterVec;
// Pick the up vector to use for the light camera
Float3 upDir = camera.Right();
Float3 minExtents;
Float3 maxExtents;
{
// Create a temporary view matrix for the light
Float3 lightCameraPos = frustumCenter;
Float3 lookAt = frustumCenter - lightDir;
XMMATRIX lightView = XMMatrixLookAtLH(lightCameraPos.ToSIMD(), lookAt.ToSIMD(), upDir.ToSIMD());
// Calculate an AABB around the frustum corners
XMVECTOR mins = XMVectorSet(REAL_MAX, REAL_MAX, REAL_MAX, REAL_MAX);
XMVECTOR maxes = XMVectorSet(-REAL_MAX, -REAL_MAX, -REAL_MAX, -REAL_MAX);
for(uint32 i = 0; i < 8; ++i)
{
XMVECTOR corner = XMVector3TransformCoord(frustumCornersWS[i], lightView);
mins = XMVectorMin(mins, corner);
maxes = XMVectorMax(maxes, corner);
}
minExtents = mins;
maxExtents = maxes;
}
// Adjust the min/max to accommodate the filtering size
float scale = (ShadowMapSize + FilterSize) / static_cast<float>(ShadowMapSize);
minExtents.x *= scale;
minExtents.y *= scale;
maxExtents.x *= scale;
maxExtents.x *= scale;
Float3 cascadeExtents = maxExtents - minExtents;
// Get position of the shadow camera
Float3 shadowCameraPos = frustumCenter + lightDir * -minExtents.z;
// Come up with a new orthographic camera for the shadow caster
OrthographicCamera shadowCamera(minExtents.x, minExtents.y, maxExtents.x,
maxExtents.y, 0.0f, cascadeExtents.z);
shadowCamera.SetLookAt(shadowCameraPos, frustumCenter, upDir);
// Draw the mesh with depth only, using the new shadow camera
RenderDepth(context, shadowCamera, true, false);
// Apply the scale/offset matrix, which transforms from [-1,1]
// post-projection space to [0,1] UV space
XMMATRIX texScaleBias;
texScaleBias.r[0] = XMVectorSet(0.5f, 0.0f, 0.0f, 0.0f);
texScaleBias.r[1] = XMVectorSet(0.0f, -0.5f, 0.0f, 0.0f);
texScaleBias.r[2] = XMVectorSet(0.0f, 0.0f, 1.0f, 0.0f);
texScaleBias.r[3] = XMVectorSet(0.5f, 0.5f, 0.0f, 1.0f);
XMMATRIX shadowMatrix = shadowCamera.ViewProjectionMatrix().ToSIMD();
shadowMatrix = XMMatrixMultiply(shadowMatrix, texScaleBias);
// Store the split distance in terms of view space depth
const float clipDist = camera.FarClip() - camera.NearClip();
shadowConstants.Data.CascadeSplits[cascadeIdx] = camera.NearClip() + splitDist * clipDist;
if(cascadeIdx == 0)
{
c0Extents = cascadeExtents;
c0Matrix = shadowMatrix;
shadowConstants.Data.ShadowMatrix = XMMatrixTranspose(shadowMatrix);
shadowConstants.Data.CascadeOffsets[0] = Float4(0.0f, 0.0f, 0.0f, 0.0f);
shadowConstants.Data.CascadeScales[0] = Float4(1.0f, 1.0f, 1.0f, 1.0f);
}
else
{
// Calculate the position of the lower corner of the cascade partition, in the UV space
// of the first cascade partition
Float4x4 invCascadeMat = Float4x4::Invert(shadowMatrix);
Float3 cascadeCorner = Float3::Transform(Float3(0.0f, 0.0f, 0.0f), invCascadeMat);
cascadeCorner = Float3::Transform(cascadeCorner, c0Matrix);
// Do the same for the upper corner
Float3 otherCorner = Float3::Transform(Float3(1.0f, 1.0f, 1.0f), invCascadeMat);
otherCorner = Float3::Transform(otherCorner, c0Matrix);
// Calculate the scale and offset
Float3 cascadeScale = Float3(1.0f, 1.0f, 1.f) / (otherCorner - cascadeCorner);
shadowConstants.Data.CascadeOffsets[cascadeIdx] = Float4(-cascadeCorner, 0.0f);
shadowConstants.Data.CascadeScales[cascadeIdx] = Float4(cascadeScale, 1.0f);
}
ConvertToEVSM(context, cascadeIdx, shadowConstants.Data.CascadeScales[cascadeIdx].To3D());
}
}
