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#pragma kernel BigTileLightListGen
#include "common.hlsl"
#include "../TilePass.cs.hlsl"
#include "../LightingConvexHullUtils.hlsl"
#if !defined(SHADER_API_XBOXONE) && !defined(SHADER_API_PSSL)
#include "../SortingComputeUtils.hlsl"
#endif
#define EXACT_EDGE_TESTS
#define PERFORM_SPHERICAL_INTERSECTION_TESTS
#define MAX_NR_BIGTILE_LIGHTS (MAX_NR_BIGTILE_LIGHTS_PLUSONE-1)
uniform int g_iNrVisibLights;
uniform uint2 g_viDimensions;
uniform float4x4 g_mInvScrProjection;
uniform float4x4 g_mScrProjection;
uniform float g_fNearPlane;
uniform float g_fFarPlane;
StructuredBuffer<float3> g_vBoundsBuffer : register( t1 );
StructuredBuffer<SFiniteLightData> g_vLightData : register( t2 );
StructuredBuffer<SFiniteLightBound> g_data : register( t3 );
#define NR_THREADS 64
// output buffer
RWBuffer<uint> g_vLightList : register( u0 );
// 2kB (room for roughly 30 wavefronts)
groupshared unsigned int lightsListLDS[MAX_NR_BIGTILE_LIGHTS_PLUSONE];
groupshared uint lightOffs;
float GetLinearDepth(float zDptBufSpace) // 0 is near 1 is far
{
float3 vP = float3(0.0f,0.0f,zDptBufSpace);
float4 v4Pres = mul(g_mInvScrProjection, float4(vP,1.0));
return v4Pres.z / v4Pres.w;
}
float3 GetViewPosFromLinDepth(float2 v2ScrPos, float fLinDepth)
{
float fSx = g_mScrProjection[0].x;
float fCx = g_mScrProjection[0].z;
float fSy = g_mScrProjection[1].y;
float fCy = g_mScrProjection[1].z;
#if USE_LEFTHAND_CAMERASPACE
return fLinDepth*float3( ((v2ScrPos.x-fCx)/fSx), ((v2ScrPos.y-fCy)/fSy), 1.0 );
#else
return fLinDepth*float3( -((v2ScrPos.x+fCx)/fSx), -((v2ScrPos.y+fCy)/fSy), 1.0 );
#endif
}
float GetOnePixDiagWorldDistAtDepthOne()
{
float fSx = g_mScrProjection[0].x;
float fSy = g_mScrProjection[1].y;
return length( float2(1.0/fSx,1.0/fSy) );
}
#ifdef PERFORM_SPHERICAL_INTERSECTION_TESTS
void SphericalIntersectionTests(uint threadID, int iNrCoarseLights, float2 screenCoordinate);
#endif
#ifdef EXACT_EDGE_TESTS
void CullByExactEdgeTests(uint threadID, int iNrCoarseLights, uint2 viTilLL, uint2 viTilUR);
#endif
[numthreads(NR_THREADS, 1, 1)]
void BigTileLightListGen(uint threadID : SV_GroupIndex, uint3 u3GroupID : SV_GroupID)
{
uint2 tileIDX = u3GroupID.xy;
uint t=threadID;
uint iWidth = g_viDimensions.x;
uint iHeight = g_viDimensions.y;
uint nrBigTilesX = (iWidth+63)/64;
uint nrBigTilesY = (iHeight+63)/64;
if(t==0) lightOffs = 0;
#if !defined(SHADER_API_XBOXONE) && !defined(SHADER_API_PSSL)
GroupMemoryBarrierWithGroupSync();
#endif
uint2 viTilLL = 64*tileIDX;
uint2 viTilUR = min( viTilLL+uint2(64,64), uint2(iWidth, iHeight) ); // not width and height minus 1 since viTilUR represents the end of the tile corner.
float2 vTileLL = float2(viTilLL.x/(float) iWidth, viTilLL.y/(float) iHeight);
float2 vTileUR = float2(viTilUR.x/(float) iWidth, viTilUR.y/(float) iHeight);
// build coarse list using AABB
for(int l=(int) t; l<(int) g_iNrVisibLights; l += NR_THREADS)
{
const float2 vMi = g_vBoundsBuffer[l].xy;
const float2 vMa = g_vBoundsBuffer[l+g_iNrVisibLights].xy;
if( all(vMa>vTileLL) && all(vMi<vTileUR))
{
unsigned int uInc = 1;
unsigned int uIndex;
InterlockedAdd(lightOffs, uInc, uIndex);
if(uIndex<MAX_NR_BIGTILE_LIGHTS) lightsListLDS[uIndex] = l; // add to light list
}
}
#if !defined(SHADER_API_XBOXONE) && !defined(SHADER_API_PSSL)
GroupMemoryBarrierWithGroupSync();
#endif
int iNrCoarseLights = min(lightOffs,MAX_NR_BIGTILE_LIGHTS);
#ifdef PERFORM_SPHERICAL_INTERSECTION_TESTS
SphericalIntersectionTests( t, iNrCoarseLights, float2(min(viTilLL.xy+uint2(64/2,64/2), uint2(iWidth-1, iHeight-1))) );
#endif
#ifdef EXACT_EDGE_TESTS
CullByExactEdgeTests(t, iNrCoarseLights, viTilLL.xy, viTilUR.xy);
#endif
// sort lights
SORTLIST(lightsListLDS, iNrCoarseLights, MAX_NR_BIGTILE_LIGHTS_PLUSONE, t, NR_THREADS);
lightOffs = 0;
GroupMemoryBarrierWithGroupSync();
for(int i=t; i<iNrCoarseLights; i+=NR_THREADS) if(lightsListLDS[i]<g_iNrVisibLights) InterlockedAdd(lightOffs, 1);
GroupMemoryBarrierWithGroupSync();
iNrCoarseLights = lightOffs;
int offs = tileIDX.y*nrBigTilesX + tileIDX.x;
for(int i=t; i<(iNrCoarseLights+1); i+=NR_THREADS)
g_vLightList[MAX_NR_BIGTILE_LIGHTS_PLUSONE*offs + i] = t==0 ? iNrCoarseLights : lightsListLDS[i-1];
}
#ifdef PERFORM_SPHERICAL_INTERSECTION_TESTS
void SphericalIntersectionTests(uint threadID, int iNrCoarseLights, float2 screenCoordinate)
{
#if USE_LEFTHAND_CAMERASPACE
float3 V = GetViewPosFromLinDepth( screenCoordinate, 1.0);
#else
float3 V = GetViewPosFromLinDepth( screenCoordinate, -1.0);
#endif
float onePixDiagDist = GetOnePixDiagWorldDistAtDepthOne();
float halfTileSizeAtZDistOne = 32*onePixDiagDist; // scale by half a tile
for(int l=threadID; l<iNrCoarseLights; l+=NR_THREADS)
{
SFiniteLightBound lgtDat = g_data[lightsListLDS[l]];
if( !DoesSphereOverlapTile(V, halfTileSizeAtZDistOne, lgtDat.center.xyz, lgtDat.radius) )
lightsListLDS[l]=0xffffffff;
}
#if !defined(SHADER_API_XBOXONE) && !defined(SHADER_API_PSSL)
GroupMemoryBarrierWithGroupSync();
#endif
}
#endif
#ifdef EXACT_EDGE_TESTS
float3 GetTileVertex(uint2 viTilLL, uint2 viTilUR, int i, float fTileFarPlane)
{
float x = (i&1)==0 ? viTilLL.x : viTilUR.x;
float y = (i&2)==0 ? viTilLL.y : viTilUR.y;
float z = (i&4)==0 ? g_fNearPlane : fTileFarPlane;
#if !USE_LEFTHAND_CAMERASPACE
z = -z;
#endif
return GetViewPosFromLinDepth( float2(x, y), z);
}
void GetFrustEdge(out float3 vP0, out float3 vE0, const int e0, uint2 viTilLL, uint2 viTilUR, float fTileFarPlane)
{
int iSection = e0>>2; // section 0 is side edges, section 1 is near edges and section 2 is far edges
int iSwizzle = e0&0x3;
int i=iSwizzle + (2*(iSection&0x2)); // offset by 4 at section 2
vP0 = GetTileVertex(uint2(viTilLL.x, viTilUR.y), uint2(viTilUR.x, viTilLL.y), i, fTileFarPlane);
vE0 = iSection==0 ? vP0 : (((iSwizzle&0x2)==0 ? 1.0f : (-1.0f))*((iSwizzle&0x1)==(iSwizzle>>1) ? float3(1,0,0) : float3(0,1,0)));
}
void CullByExactEdgeTests(uint threadID, int iNrCoarseLights, uint2 viTilLL, uint2 viTilUR)
{
const bool bOnlyNeedFrustumSideEdges = true;
const int nrFrustEdges = bOnlyNeedFrustumSideEdges ? 4 : 8; // max 8 since we never need to test 4 far edges of frustum since they are identical vectors to near edges and plane is placed at vP0 on light hull.
const int totNrEdgePairs = 12*nrFrustEdges;
for(int l=0; l<iNrCoarseLights; l++)
{
const int idxCoarse = lightsListLDS[l];
[branch]if(idxCoarse<(uint) g_iNrVisibLights && g_vLightData[idxCoarse].lightType!=SPHERE_LIGHT) // don't bother doing edge tests for sphere lights since these have camera aligned bboxes.
{
SFiniteLightBound lgtDat = g_data[idxCoarse];
const float3 boxX = lgtDat.boxAxisX.xyz;
const float3 boxY = lgtDat.boxAxisY.xyz;
const float3 boxZ = -lgtDat.boxAxisZ.xyz; // flip axis (so it points away from the light direction for a spot-light)
const float3 center = lgtDat.center.xyz;
const float2 scaleXY = lgtDat.scaleXY;
for(int i=threadID; i<totNrEdgePairs; i+=NR_THREADS)
{
int e0 = (int) (((uint)i)/((uint) nrFrustEdges)); // should become a shift right
int e1 = i - e0*nrFrustEdges;
int idx_cur=0, idx_twin=0;
float3 vP0, vE0;
GetHullEdge(idx_cur, idx_twin, vP0, vE0, e0, boxX, boxY, boxZ, center, scaleXY);
float3 vP1, vE1;
GetFrustEdge(vP1, vE1, e1, viTilLL, viTilUR, g_fFarPlane);
// potential separation plane
float3 vN = cross(vE0, vE1);
int positive=0, negative=0;
for(int k=1; k<8; k++) // only need to test 7 verts (technically just 6).
{
int j = (idx_cur+k)&0x7;
float3 vPh = GetHullVertex(boxX, boxY, boxZ, center, scaleXY, j);
float fSignDist = idx_twin==j ? 0.0 : dot(vN, vPh-vP0);
if(fSignDist>0) ++positive; else if(fSignDist<0) ++negative;
}
int resh = (positive>0 && negative>0) ? 0 : (positive>0 ? 1 : (negative>0 ? (-1) : 0));
positive=0; negative=0;
for(int j=0; j<8; j++)
{
float3 vPf = GetTileVertex(viTilLL, viTilUR, j, g_fFarPlane);
float fSignDist = dot(vN, vPf-vP0);
if(fSignDist>0) ++positive; else if(fSignDist<0) ++negative;
}
int resf = (positive>0 && negative>0) ? 0 : (positive>0 ? 1 : (negative>0 ? (-1) : 0));
bool bFoundSepPlane = (resh*resf)<0;
if(bFoundSepPlane) lightsListLDS[l]=0xffffffff;
}
}
}
#if !defined(SHADER_API_XBOXONE) && !defined(SHADER_API_PSSL)
GroupMemoryBarrierWithGroupSync();
#endif
}
#endif