Method SetupForPlanarView

src/render/CascadedShadowMap.cpp:81–150

}

bool CascadedShadowMap::SetupForPlanarView(const DirectionalLight& light, frustum viewFrustum, float maxShadowDistance, float lightSpaceZUp, float lightSpaceZDown, float exponent, float3 preViewTranslation, int numberOfCascades)
{
    assert(exponent > 1);

    assert(length(viewFrustum.planes[frustum::NEAR_PLANE].normal) > 0);

    if (numberOfCascades < 0)
        m_NumberOfCascades = static_cast<int>(m_Cascades.size());
    else
        m_NumberOfCascades = std::min(numberOfCascades, static_cast<int>(m_Cascades.size()));

    if (maxShadowDistance > 0.f)
    {
        plane& nearPlane = viewFrustum.planes[frustum::NEAR_PLANE];
        plane& farPlane = viewFrustum.planes[frustum::FAR_PLANE];
        farPlane.normal = -nearPlane.normal;
        farPlane.distance = -nearPlane.distance + maxShadowDistance;
    }
    else
    {
        assert(length(viewFrustum.planes[frustum::FAR_PLANE].normal) > 0);
    }

    std::array<float3, frustum::numCorners> corners;
    for (uint32_t i = 0; i < frustum::numCorners; i++)
    {
        corners[i] = viewFrustum.getCorner(i);
    }

    float far = 1.f;
    float near = far / exponent;
    
    daffine3 viewToWorld = light.GetNode()->GetLocalToWorldTransform();
    viewToWorld = dm::scaling(dm::double3(1.0, 1.0, -1.0)) * viewToWorld;
    affine3 worldToView = affine3(inverse(viewToWorld));
    bool viewModified = false;

    for (int cascade = m_NumberOfCascades - 1; cascade >= 0; cascade--)
    {
        if (cascade == 0)
            near = 0.f;

        std::array<float3, frustum::numCorners> cascadeViewCorners;
        for (uint32_t i = 0; i < frustum::numCorners; i++)
        {
            float3 corner = lerp(corners[i & 3], corners[(i & 3) + 4], (i & 4) ? far : near);
            cascadeViewCorners[i] = worldToView.transformPoint(corner);
        }

        box3 cascadeViewBounds = box3(frustum::numCorners, cascadeViewCorners.data());

        float3 cascadeCenter = dm::float3(viewToWorld.transformPoint(dm::double3(cascadeViewBounds.center())));
        float3 halfShadowBoxSize = cascadeViewBounds.diagonal() * 0.5f;
        halfShadowBoxSize.xy() = std::max(halfShadowBoxSize.x, halfShadowBoxSize.y);
        float fadeRange = halfShadowBoxSize.x * 0.1f;

        float zDown = std::max(halfShadowBoxSize.z, lightSpaceZDown);
        float zUp = std::max(halfShadowBoxSize.z, lightSpaceZUp);