public static DepthReadback GetDepthReadback(RenderContext context)
{
var sceneCameraRenderer = context.Tags.Get(SceneCameraRenderer.Current);
DepthReadback depthReadBack;
for (int i = 0; i < sceneCameraRenderer.PostRenderers.Count; i++)
{
depthReadBack = sceneCameraRenderer.PostRenderers[i] as DepthReadback;
if (depthReadBack != null)
{
return(depthReadBack);
}
}
depthReadBack = new DepthReadback();
sceneCameraRenderer.PostRenderers.Add(depthReadBack);
return(depthReadBack);
}
public static DepthReadback GetDepthReadback(RenderContext context)
{
var sceneCameraRenderer = context.Tags.Get(SceneCameraRenderer.Current);
DepthReadback depthReadBack;
for (int i = 0; i < sceneCameraRenderer.PostRenderers.Count; i++)
{
depthReadBack = sceneCameraRenderer.PostRenderers[i] as DepthReadback;
if (depthReadBack != null)
{
return depthReadBack;
}
}
depthReadBack = new DepthReadback();
sceneCameraRenderer.PostRenderers.Add(depthReadBack);
return depthReadBack;
}
private Vector2 ComputeCascadeSplits(RenderContext context, ShadowMapRenderer shadowContext, ref LightShadowMapTexture lightShadowMap)
{
var shadow = (LightDirectionalShadowMap)lightShadowMap.Shadow;
var cameraNear = shadowContext.Camera.NearClipPlane;
var cameraFar = shadowContext.Camera.FarClipPlane;
var cameraRange = cameraFar - cameraNear;
var minDistance = cameraNear + LightDirectionalShadowMap.DepthRangeParameters.DefaultMinDistance;
var maxDistance = cameraNear + LightDirectionalShadowMap.DepthRangeParameters.DefaultMaxDistance;
if (shadow.DepthRange.IsAutomatic)
{
var depthReadBack = DepthReadback.GetDepthReadback(context);
if (depthReadBack.IsResultAvailable)
{
var depthMinMax = depthReadBack.DepthMinMax;
minDistance = ToLinearDepth(depthMinMax.X, ref shadowContext.Camera.ProjectionMatrix);
// Reserve 1/3 of the guard distance for the min distance
minDistance = Math.Max(cameraNear, minDistance - shadow.DepthRange.GuardDistance / 3);
// Reserve 2/3 of the guard distance for the max distance
var guardMaxDistance = minDistance + shadow.DepthRange.GuardDistance * 2 / 3;
maxDistance = ToLinearDepth(depthMinMax.Y, ref shadowContext.Camera.ProjectionMatrix);
maxDistance = Math.Max(maxDistance, guardMaxDistance);
}
}
else
{
minDistance = cameraNear + shadow.DepthRange.ManualMinDistance;
maxDistance = cameraNear + shadow.DepthRange.ManualMaxDistance;
}
var manualPartitionMode = shadow.PartitionMode as LightDirectionalShadowMap.PartitionManual;
var logarithmicPartitionMode = shadow.PartitionMode as LightDirectionalShadowMap.PartitionLogarithmic;
if (logarithmicPartitionMode != null)
{
var minZ = minDistance;
var maxZ = maxDistance;
var range = maxZ - minZ;
var ratio = maxZ / minZ;
var logRatio = MathUtil.Clamp(1.0f - logarithmicPartitionMode.PSSMFactor, 0.0f, 1.0f);
for (int cascadeLevel = 0; cascadeLevel < lightShadowMap.CascadeCount; ++cascadeLevel)
{
// Compute cascade split (between znear and zfar)
float distrib = (float)(cascadeLevel + 1) / lightShadowMap.CascadeCount;
float logZ = (float)(minZ * Math.Pow(ratio, distrib));
float uniformZ = minZ + range * distrib;
float distance = MathUtil.Lerp(uniformZ, logZ, logRatio);
cascadeSplitRatios[cascadeLevel] = distance;
}
}
else if (manualPartitionMode != null)
{
if (lightShadowMap.CascadeCount == 1)
{
cascadeSplitRatios[0] = minDistance + manualPartitionMode.SplitDistance1 * maxDistance;
}
else if (lightShadowMap.CascadeCount == 2)
{
cascadeSplitRatios[0] = minDistance + manualPartitionMode.SplitDistance1 * maxDistance;
cascadeSplitRatios[1] = minDistance + manualPartitionMode.SplitDistance3 * maxDistance;
}
else if (lightShadowMap.CascadeCount == 4)
{
cascadeSplitRatios[0] = minDistance + manualPartitionMode.SplitDistance0 * maxDistance;
cascadeSplitRatios[1] = minDistance + manualPartitionMode.SplitDistance1 * maxDistance;
cascadeSplitRatios[2] = minDistance + manualPartitionMode.SplitDistance2 * maxDistance;
cascadeSplitRatios[3] = minDistance + manualPartitionMode.SplitDistance3 * maxDistance;
}
}
// Convert distance splits to ratios cascade in the range [0, 1]
for (int i = 0; i < cascadeSplitRatios.Length; i++)
{
cascadeSplitRatios[i] = (cascadeSplitRatios[i] - cameraNear) / cameraRange;
}
return(new Vector2(minDistance, maxDistance));
}
