public Shadowmap(Device device)
{
TextureSize = 1024; //todo: make this a setting...
CascadeCount = Math.Min(Settings.Default.ShadowCascades, 8); // 6; //use setting
PCFSize = 3;
PCFOffset = 0.000125f; //0.002f
BlurBetweenCascades = 0.05f;
ShadowVars = new GpuVarsBuffer <ShadowmapVars>(device);
DepthTexture = DXUtility.CreateTexture2D(device, TextureSize * CascadeCount, TextureSize, 1, 1, Format.R32_Typeless, 1, 0, ResourceUsage.Default, BindFlags.DepthStencil | BindFlags.ShaderResource, 0, 0);
DepthTextureSS = DXUtility.CreateSamplerState(device, TextureAddressMode.Border, new Color4(0.0f), Comparison.Less, Filter.ComparisonMinMagLinearMipPoint, 0, 0.0f, 0.0f, 0.0f);
DepthTextureSRV = DXUtility.CreateShaderResourceView(device, DepthTexture, Format.R32_Float, ShaderResourceViewDimension.Texture2D, 1, 0, 0, 0);
DepthTextureDSV = DXUtility.CreateDepthStencilView(device, DepthTexture, Format.D32_Float, DepthStencilViewDimension.Texture2D);
Cascades = new List <ShadowmapCascade>(CascadeCount);
for (int i = 0; i < CascadeCount; i++)
{
ShadowmapCascade c = new ShadowmapCascade();
c.Owner = this;
c.Index = i;
c.ZNear = 0.0f;
c.ZFar = 1.0f;
c.IntervalNear = 0.0f;
c.IntervalFar = 1.0f;
c.DepthRenderVP = new ViewportF()
{
Height = (float)TextureSize,
Width = (float)TextureSize,
MaxDepth = 1.0f,
MinDepth = 0.0f,
X = (float)(TextureSize * i),
Y = 0,
};
Cascades.Add(c);
}
DepthRenderRS = DXUtility.CreateRasterizerState(device, FillMode.Solid, CullMode.None, true, false, true, 0, 0.0f, 1.0f);
DepthRenderDS = DXUtility.CreateDepthStencilState(device, true, DepthWriteMask.All);
DepthRenderVP = new ViewportF();
DepthRenderVP.Height = (float)TextureSize;
DepthRenderVP.Width = (float)TextureSize;
DepthRenderVP.MaxDepth = 1.0f;
DepthRenderVP.MinDepth = 0.0f;
DepthRenderVP.X = 0;
DepthRenderVP.Y = 0;
graphicsMemoryUsage = (long)(TextureSize * TextureSize * CascadeCount * 4);
}
public void SetFinalRenderResources(DeviceContext context)
{
ShadowVars.Vars.CamScenePos = new Vector4(SceneCamPos, 0.0f); //in shadow scene coords
ShadowVars.Vars.CamSceneView = Matrix.Transpose(SceneCamView);
ShadowVars.Vars.LightView = Matrix.Transpose(LightView);
ShadowVars.Vars.LightDir = new Vector4(LightDirection, 0.0f);
Matrix dxmatTextureScale = Matrix.Scaling(0.5f, -0.5f, 1.0f);
Matrix dxmatTextureTranslation = Matrix.Translation(0.5f, 0.5f, 0.0f);
Matrix dxmatTextureST = Matrix.Multiply(dxmatTextureScale, dxmatTextureTranslation);
for (int i = 0; i < CascadeCount; ++i)
{
ShadowmapCascade cascade = Cascades[i];
Matrix mShadowTexture = Matrix.Multiply(cascade.Ortho, dxmatTextureST);
ShadowVars.Vars.CascadeScales.Set(i, new Vector4(mShadowTexture.M11, mShadowTexture.M22, mShadowTexture.M33, 1.0f));
ShadowVars.Vars.CascadeOffsets.Set(i, new Vector4(mShadowTexture.M41, mShadowTexture.M42, mShadowTexture.M43, 0.0f));
ShadowVars.Vars.CascadeDepths.Set(i, new Vector4(cascade.IntervalFar, 0.0f, 0.0f, 0.0f));
}
ShadowVars.Vars.CascadeCount = CascadeCount;
ShadowVars.Vars.CascadeVisual = 0;
ShadowVars.Vars.PCFLoopStart = (PCFSize) / -2;
ShadowVars.Vars.PCFLoopEnd = (PCFSize) / 2 + 1;
// The border padding values keep the pixel shader from reading the borders during PCF filtering.
float txs = (float)TextureSize;
ShadowVars.Vars.BorderPaddingMax = (txs - 1.0f) / txs;
ShadowVars.Vars.BorderPaddingMin = 1.0f / txs;
ShadowVars.Vars.Bias = PCFOffset;
ShadowVars.Vars.BlurBetweenCascades = BlurBetweenCascades;
ShadowVars.Vars.CascadeCountInv = 1.0f / (float)CascadeCount;
ShadowVars.Vars.TexelSize = 1.0f / txs;
ShadowVars.Vars.TexelSizeX = ShadowVars.Vars.TexelSize / (float)CascadeCount;
ShadowVars.Vars.ShadowMaxDistance = maxShadowDistance;
ShadowVars.Update(context);
SetBuffers(context);
}
public void BeginDepthRender(DeviceContext context, int cascadeIndex)
{
ShadowmapCascade cascade = Cascades[cascadeIndex];
context.Rasterizer.SetViewport(cascade.DepthRenderVP);
}
public void BeginUpdate(DeviceContext context, Camera cam, Vector3 lightDir, List <RenderableGeometryInst> items)
{
//items should be potential shadow casters.
RTS.Set(context);
var ppos = cam.Position;
var view = cam.ViewMatrix;
var proj = cam.ProjMatrix;
var viewproj = cam.ViewProjMatrix;
//need to compute a local scene space for the shadows. use a snapped version of the camera coords...
Vector3 pp = ppos;
float snapsize = 20.0f; //20m snap... //ideally should snap to texel size
SceneOrigin.X = pp.X - (pp.X % snapsize);
SceneOrigin.Y = pp.Y - (pp.Y % snapsize);
SceneOrigin.Z = pp.Z - (pp.Z % snapsize);
SceneCamPos = (pp - SceneOrigin);
//the items passed in here are visible items. need to compute the scene bounds from these.
Vector4 vFLTMAX = new Vector4(float.MaxValue);
Vector4 vFLTMIN = new Vector4(float.MinValue);
Vector3 vHMAX = new Vector3(float.MaxValue);
Vector3 vHMIN = new Vector3(float.MinValue);
WorldMin = vHMAX;
WorldMax = vHMIN;
for (int i = 0; i < items.Count; i++)
{
var inst = items[i].Inst;
Vector3 imin = inst.BBMin - 100.0f; //extra bias to make sure scene isn't too small in model view...
Vector3 imax = inst.BBMax + 100.0f;
WorldMin = Vector3.Min(WorldMin, imin);
WorldMax = Vector3.Max(WorldMax, imax);
}
SceneMin = (WorldMin - SceneOrigin);
SceneMax = (WorldMax - SceneOrigin);
SceneCenter = (SceneMax + SceneMin) * 0.5f;
SceneExtent = (SceneMax - SceneMin) * 0.5f;
Matrix sceneCamTrans = Matrix.Translation(-SceneCamPos);
SceneCamView = Matrix.Multiply(sceneCamTrans, view);
Matrix camViewInv = Matrix.Invert(SceneCamView);
Vector3 lightUp = new Vector3(0.0f, 1.0f, 0.0f); //BUG: should select this depending on light dir!?
LightView = Matrix.LookAtLH(lightDir, Vector3.Zero, lightUp); //BUG?: pos/lightdir wrong way around??
LightDirection = lightDir;
Vector4[] vSceneAABBPointsLightSpace = new Vector4[8];
// This function simply converts the center and extents of an AABB into 8 points
CreateAABBPoints(ref vSceneAABBPointsLightSpace, SceneCenter, SceneExtent);
// Transform the scene AABB to Light space.
for (int index = 0; index < 8; ++index)
{
vSceneAABBPointsLightSpace[index] = LightView.Multiply(vSceneAABBPointsLightSpace[index]);
}
float fFrustumIntervalBegin, fFrustumIntervalEnd;
Vector4 vLightCameraOrthographicMin; // light space frustrum aabb
Vector4 vLightCameraOrthographicMax;
//float[] fCascadeIntervals = { 7.5f, 20.0f, 60.0f, 150.0f, 500.0f, 1000.0f, 1500.0f, 2500.0f };
//float[] fCascadeIntervals = { 7.0f, 20.0f, 65.0f, 160.0f, 650.0f, 2000.0f, 5000.0f, 10000.0f };
Vector4 vWorldUnitsPerTexel = Vector4.Zero;
float fInvTexelCount = 1.0f / (float)TextureSize;
// We loop over the cascades to calculate the orthographic projection for each cascade.
for (int iCascadeIndex = 0; iCascadeIndex < CascadeCount; ++iCascadeIndex)
{
ShadowmapCascade cascade = Cascades[iCascadeIndex];
fFrustumIntervalBegin = 0.0f;
// Scale the intervals between 0 and 1. They are now percentages that we can scale with.
fFrustumIntervalEnd = fCascadeIntervals[iCascadeIndex];
//fFrustumIntervalBegin = fFrustumIntervalBegin * fCameraNearFarRange;
//fFrustumIntervalEnd = fFrustumIntervalEnd * fCameraNearFarRange;
Vector4[] vFrustumPoints = new Vector4[8];
// This function takes the began and end intervals along with the projection matrix and returns the 8
// points that repreresent the cascade Interval
CreateFrustumPointsFromCascadeInterval(fFrustumIntervalBegin, fFrustumIntervalEnd, proj, ref vFrustumPoints);
vLightCameraOrthographicMin = vFLTMAX;
vLightCameraOrthographicMax = vFLTMIN;
Vector4 vTempTranslatedCornerPoint;
// This next section of code calculates the min and max values for the orthographic projection.
for (int icpIndex = 0; icpIndex < 8; ++icpIndex)
{
// Transform the frustum from camera view space to world space.
vFrustumPoints[icpIndex] = camViewInv.Multiply(vFrustumPoints[icpIndex]);
// Transform the point from world space to Light Camera Space.
vTempTranslatedCornerPoint = LightView.Multiply(vFrustumPoints[icpIndex]);
// Find the closest point.
vLightCameraOrthographicMin = Vector4.Min(vTempTranslatedCornerPoint, vLightCameraOrthographicMin);
vLightCameraOrthographicMax = Vector4.Max(vTempTranslatedCornerPoint, vLightCameraOrthographicMax);
}
// This code removes the shimmering effect along the edges of shadows due to
// the light changing to fit the camera.
// Fit the ortho projection to the cascades far plane and a near plane of zero.
// Pad the projection to be the size of the diagonal of the Frustum partition.
//
// To do this, we pad the ortho transform so that it is always big enough to cover
// the entire camera view frustum.
Vector4 vDiagonal = (vFrustumPoints[0] - vFrustumPoints[6]);
// The bound is the length of the diagonal of the frustum interval.
float fCascadeBound = vDiagonal.XYZ().Length();
vDiagonal = new Vector4(fCascadeBound);
// The offset calculated will pad the ortho projection so that it is always the same size
// and big enough to cover the entire cascade interval.
Vector4 vBorderOffset = (vDiagonal - (vLightCameraOrthographicMax - vLightCameraOrthographicMin)) * 0.5f;
// Set the Z and W components to zero.
//vBoarderOffset *= g_vMultiplySetzwToZero;
vBorderOffset.Z = 0.0f;
vBorderOffset.W = 0.0f;
// Add the offsets to the projection.
vLightCameraOrthographicMax += vBorderOffset;
vLightCameraOrthographicMin -= vBorderOffset;
// The world units per texel are used to snap the shadow the orthographic projection
// to texel sized increments. This keeps the edges of the shadows from shimmering.
float fWorldUnitsPerTexel = fCascadeBound / (float)TextureSize;
vWorldUnitsPerTexel = new Vector4(fWorldUnitsPerTexel, fWorldUnitsPerTexel, 1.0f, 1.0f); //1.0 instead of 0.0 to remove divide by 0
// We snap the camera to 1 pixel increments so that moving the camera does not cause the shadows to jitter.
// This is a matter of integer dividing by the world space size of a texel
vLightCameraOrthographicMin = vLightCameraOrthographicMin / vWorldUnitsPerTexel;
vLightCameraOrthographicMin = vLightCameraOrthographicMin.Floor();
vLightCameraOrthographicMin = vLightCameraOrthographicMin * vWorldUnitsPerTexel;
vLightCameraOrthographicMax = vLightCameraOrthographicMax / vWorldUnitsPerTexel;
vLightCameraOrthographicMax = vLightCameraOrthographicMax.Floor();
vLightCameraOrthographicMax = vLightCameraOrthographicMax * vWorldUnitsPerTexel;
//These are the unconfigured near and far plane values. They are purposly awful to show
// how important calculating accurate near and far planes is.
float fNearPlane;
float fFarPlane;
// By intersecting the light frustum with the scene AABB we can get a tighter bound on the near and far plane.
ComputeNearAndFar(out fNearPlane, out fFarPlane, vLightCameraOrthographicMin, vLightCameraOrthographicMax, vSceneAABBPointsLightSpace);
// Create the orthographic projection for this cascade.
cascade.Ortho = Matrix.OrthoOffCenterLH(vLightCameraOrthographicMin.X, vLightCameraOrthographicMax.X, vLightCameraOrthographicMin.Y, vLightCameraOrthographicMax.Y, fNearPlane, fFarPlane);
cascade.ZNear = fNearPlane;
cascade.ZFar = fFarPlane;
cascade.IntervalNear = fFrustumIntervalBegin;
cascade.IntervalFar = fFrustumIntervalEnd;
cascade.Matrix = Matrix.Multiply(LightView, cascade.Ortho);
cascade.MatrixInv = Matrix.Invert(cascade.Matrix);
cascade.WorldUnitsPerTexel = fWorldUnitsPerTexel;
cascade.WorldUnitsToCascadeUnits = 2.0f / fCascadeBound;
}
context.ClearDepthStencilView(DepthTextureDSV, DepthStencilClearFlags.Depth, 1.0f, 0);
// Set a null render target so as not to render color.
context.OutputMerger.SetRenderTargets(DepthTextureDSV, (RenderTargetView)null);
context.OutputMerger.SetDepthStencilState(DepthRenderDS);
context.Rasterizer.State = DepthRenderRS;
}
