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deviceCode.cu
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deviceCode.cu
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// ======================================================================== //
// Copyright 2022-2022 Stefan Zellmann //
// //
// Licensed under the Apache License, Version 2.0 (the "License"); //
// you may not use this file except in compliance with the License. //
// You may obtain a copy of the License at //
// //
// http://www.apache.org/licenses/LICENSE-2.0 //
// //
// Unless required by applicable law or agreed to in writing, software //
// distributed under the License is distributed on an "AS IS" BASIS, //
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. //
// See the License for the specific language governing permissions and //
// limitations under the License. //
// ======================================================================== //
#include <float.h>
#include "LaunchParams.h"
#include "Grid.cuh"
#include "KDTree.cuh"
#include "Plane.h"
#include "DDA.h"
using owl::vec2f;
using owl::vec2i;
using owl::vec3f;
using owl::vec3i;
using owl::vec4f;
using owl::vec4i;
namespace exa {
extern "C" __constant__ LaunchParams optixLaunchParams;
typedef owl::RayT<RADIANCE_RAY_TYPE,2> Ray;
// ------------------------------------------------------------------
// helpers
// ------------------------------------------------------------------
typedef owl::common::LCG<4> Random;
inline __device__
vec3f backGroundColor()
{
const vec2i pixelID = owl::getLaunchIndex();
const float t = pixelID.y / (float)optixGetLaunchDimensions().y;
const vec3f c = (1.0f - t)*vec3f(1.0f, 1.0f, 1.0f) + t * vec3f(0.5f, 0.7f, 1.0f);
return c;
}
inline __device__
float intersect(const Ray &ray, const Plane &plane, bool &backFace)
{
const float s = dot(plane.N,ray.direction);
if (s == 0.f)
return FLT_MAX;
backFace = s > 0.f;
return (plane.d - dot(plane.N,ray.origin)) / s;
}
inline __device__ vec3f randomColor(unsigned idx)
{
unsigned int r = (unsigned int)(idx*13*17 + 0x234235);
unsigned int g = (unsigned int)(idx*7*3*5 + 0x773477);
unsigned int b = (unsigned int)(idx*11*19 + 0x223766);
return vec3f((r&255)/255.f,
(g&255)/255.f,
(b&255)/255.f);
}
inline __device__ int getNumLights()
{
auto &lp = optixLaunchParams;
int numLights = 0;
for (int i=0; i<LIGHTS_MAX; ++i) {
if (lp.lights[i].on) numLights++;
}
return numLights;
}
inline __device__ int uniformSampleOneLight(Random &rnd, int numLights)
{
int which = int(rnd() * numLights); if (which == numLights) which = 0;
return which;
}
inline __device__ Ray generateRay(const vec2f screen)
{
auto &lp = optixLaunchParams;
vec3f org = lp.camera.org;
vec3f dir
= lp.camera.dir_00
+ screen.u * lp.camera.dir_du
+ screen.v * lp.camera.dir_dv;
dir = normalize(dir);
if (fabs(dir.x) < 1e-5f) dir.x = 1e-5f;
if (fabs(dir.y) < 1e-5f) dir.y = 1e-5f;
if (fabs(dir.z) < 1e-5f) dir.z = 1e-5f;
return Ray(org,dir,0.f,1e10f);
}
inline __device__
float firstSampleT(const range1f &rayInterval,
const float dt,
const float ils_t0)
{
float numSegsf = floor((rayInterval.lower - dt*ils_t0)/dt);
float t = dt * (ils_t0 + numSegsf);
if (t < rayInterval.lower) t += dt;
return t;
}
inline __device__ box2f subImageUV()
{
return optixLaunchParams.subImage.value;
}
inline __device__ box2i subImageWin()
{
const vec2i lo = clamp(vec2i(optixLaunchParams.subImage.value.lower*vec2f(owl::getLaunchDims())),
vec2i(0),vec2i(owl::getLaunchDims()-1));
const vec2i hi = clamp(vec2i(optixLaunchParams.subImage.value.upper*vec2f(owl::getLaunchDims())),
vec2i(0),vec2i(owl::getLaunchDims()-1));
return {lo,hi};
}
inline __device__ box2f subImageSelectionUV()
{
return optixLaunchParams.subImage.selection;
}
inline __device__ box2i subImageSelectionWin()
{
const vec2i lo = clamp(vec2i(optixLaunchParams.subImage.selection.lower*vec2f(owl::getLaunchDims())),
vec2i(0),vec2i(owl::getLaunchDims()-1));
const vec2i hi = clamp(vec2i(optixLaunchParams.subImage.selection.upper*vec2f(owl::getLaunchDims())),
vec2i(0),vec2i(owl::getLaunchDims()-1));
return {lo,hi};
}
inline __device__ void make_orthonormal_basis(vec3f &u, vec3f &v, const vec3f &w)
{
v = fabsf(w.x) > fabsf(w.y) ? normalize(vec3f(-w.z,0.f,w.x))
: normalize(vec3f(0.f,w.z,-w.y));
u = cross(v, w);
}
inline __device__ vec4f over(const vec4f &A, const vec4f &B)
{
return A + (1.f-A.w)*B;
}
inline __device__ vec3f hue_to_rgb(float hue)
{
float s = __saturatef( hue ) * 6.0f;
float r = __saturatef( fabsf(s - 3.f) - 1.0f );
float g = __saturatef( 2.0f - fabsf(s - 2.0f) );
float b = __saturatef( 2.0f - fabsf(s - 4.0f) );
return vec3f(r, g, b);
}
inline __device__ vec3f temperature_to_rgb(float t)
{
float K = 4.0f / 6.0f;
float h = K - K * t;
float v = .5f + 0.5f * t; return v * hue_to_rgb(h);
}
inline __device__
vec3f heatMap(float t)
{
#if 1
return temperature_to_rgb(t);
#else
if (t < .25f) return lerp(vec3f(0.f,1.f,0.f),vec3f(0.f,1.f,1.f),(t-0.f)/.25f);
if (t < .5f) return lerp(vec3f(0.f,1.f,1.f),vec3f(0.f,0.f,1.f),(t-.25f)/.25f);
if (t < .75f) return lerp(vec3f(0.f,0.f,1.f),vec3f(1.f,1.f,1.f),(t-.5f)/.25f);
if (t < 1.f) return lerp(vec3f(1.f,1.f,1.f),vec3f(1.f,0.f,0.f),(t-.75f)/.25f);
return vec3f(1.f,0.f,0.f);
#endif
}
// ------------------------------------------------------------------
// Spatial domains, in case we have own majorants
// ------------------------------------------------------------------
OPTIX_CLOSEST_HIT_PROGRAM(MajorantsGeomCH)()
{
}
OPTIX_BOUNDS_PROGRAM(MajorantsGeomBounds)(const void* geomData,
box3f& result,
int leafID)
{
const MajorantsGeom &self = *(const MajorantsGeom *)geomData;
if (self.maxOpacities[leafID] == 0.f) {
result.lower = vec3f(+1e30f);
result.upper = vec3f(-1e30f);
} else {
result = self.domains[leafID];
// printf("%i, %f,%f,%f %f,%f,%f\n",leafID,
// result.lower.x,result.lower.y,result.lower.z,
// result.upper.x,result.upper.y,result.upper.z);
}
}
OPTIX_INTERSECT_PROGRAM(MajorantsGeomIsect)()
{
const MajorantsGeom &self = owl::getProgramData<MajorantsGeom>();
int leafID = optixGetPrimitiveIndex();
owl::Ray ray(optixGetObjectRayOrigin(),
optixGetObjectRayDirection(),
optixGetRayTmin(),
optixGetRayTmax());
const box3f &bounds = self.domains[leafID];
// printf("%i, %f,%f,%f %f,%f,%f\n",leafID,
// bounds.lower.x,bounds.lower.y,bounds.lower.z,
// bounds.upper.x,bounds.upper.y,bounds.upper.z);
float t0 = ray.tmin, t1 = ray.tmax;
if (!boxTest(ray,bounds,t0,t1))
return;
if (optixReportIntersection(t0, 0)) {
DomainPRD& prd = owl::getPRD<DomainPRD>();
prd.t0 = t0;
prd.t1 = t1;
prd.domainID = leafID;
}
}
// ------------------------------------------------------------------
// Macro Cell Grids
// ------------------------------------------------------------------
OPTIX_CLOSEST_HIT_PROGRAM(MacroCellGeomCH)()
{
}
OPTIX_BOUNDS_PROGRAM(MacroCellGeomBounds)(const void* geomData,
box3f& result,
int leafID)
{
const MacroCellGeom &self = *(const MacroCellGeom *)geomData;
if (self.maxOpacities[leafID] == 0.f) {
result.lower = vec3f(+1e30f);
result.upper = vec3f(-1e30f);
} else {
const vec3i index = gridIndex(leafID, self.dims);
result.lower = self.spacing * vec3f(index) + self.origin;
result.upper = self.spacing + result.lower;
}
// printf("bounds (%f,%f,%f) (%f,%f,%f)\n",
// result.lower.x,result.lower.y,result.lower.z,
// result.upper.x,result.upper.y,result.upper.z);
}
OPTIX_INTERSECT_PROGRAM(MacroCellGeomIsect)() // for non-zero length rays
{
const MacroCellGeom &self = owl::getProgramData<MacroCellGeom>();
int leafID = optixGetPrimitiveIndex();
owl::Ray ray(optixGetObjectRayOrigin(),
optixGetObjectRayDirection(),
optixGetRayTmin(),
optixGetRayTmax());
const auto index = gridIndex(leafID, self.dims);
box3f bounds;
bounds.lower = self.spacing * vec3f(index) + self.origin;
bounds.upper = self.spacing + bounds.lower;
float t0 = ray.tmin, t1 = ray.tmax;
if (!boxTest(ray,bounds,t0,t1))
return;
if (optixReportIntersection(t0, 0)) {
DomainPRD& prd = owl::getPRD<DomainPRD>();
prd.t0 = t0;
prd.t1 = t1;
prd.domainID = leafID;
}
}
// ------------------------------------------------------------------
// Triangle meshes
// ------------------------------------------------------------------
struct MeshPRD {
int primID;
float t_hit;
vec3f Ng;
vec3f kd;
};
OPTIX_CLOSEST_HIT_PROGRAM(MeshGeomCH)()
{
const MeshGeom &self = owl::getProgramData<MeshGeom>();
MeshPRD &prd = owl::getPRD<MeshPRD>();
prd.t_hit = optixGetRayTmax();
prd.primID = optixGetPrimitiveIndex();
vec3i index = self.indexBuffer[prd.primID];
vec3f v1 = self.vertexBuffer[index.x];
vec3f v2 = self.vertexBuffer[index.y];
vec3f v3 = self.vertexBuffer[index.z];
prd.Ng = normalize(vec3f(optixTransformNormalFromObjectToWorldSpace(cross(v2-v1,v3-v1))));
prd.kd = vec3f(.8f);
}
inline __device__
vec4f lookupTransferFunction(float f)
{
auto &lp = optixLaunchParams;
const range1f xfDomain = lp.transferFunc.domain;
if (xfDomain.lower >= xfDomain.upper)
return vec4f(0.f);
f -= xfDomain.lower;
f /= (xfDomain.upper-xfDomain.lower);
#ifdef EXASTITCH_CUDA_TEXTURE_TF
return tex2D<float4>(lp.transferFunc.texture,f,.5f);
#else
if (lp.transferFunc.numValues == 0)
return vec4f(0.f);
f = max(0.f,min(1.f,f));
int i = min(lp.transferFunc.numValues-1,int(f * lp.transferFunc.numValues));
return lp.transferFunc.values[i];
#endif
}
// ------------------------------------------------------------------
// Generic integration sampler for DVR and ISOs
// ------------------------------------------------------------------
template <typename Sampler, bool Shading=true>
inline __device__
vec4f integrateDVR(const Sampler &sampler, Ray ray, float t0, float t1, float ils_t0 = 0.f, const int numLights =0)
{
auto &lp = optixLaunchParams;
// first, since we now traverse bricks and sample cells: convert ray to voxel space...
ray.origin = xfmPoint(lp.voxelSpaceTransform,ray.origin);
ray.direction = xfmVector(lp.voxelSpaceTransform,ray.direction);
const float dt_scale = length(vec3f(ray.direction));
ray.direction = normalize(vec3f(ray.direction));
ray.tmin = ray.tmin * dt_scale;
ray.tmax = ray.tmax * dt_scale;
float dt = lp.render.dt;
vec4f color = 0.f;
for (float t=firstSampleT({t0,t1},dt,ils_t0); t<=t1; t+=dt) {
const vec3f pos = ray.origin+ray.direction*t;
Sample s = sample(sampler,{},pos);
if (s.primID < 0)
continue;
const vec4f xf = lookupTransferFunction(s.value);
if constexpr (Shading) {
const vec3f g;// = gradient(pos);
const vec3f N = g / (length(g + 1e-4f));
const vec3f cd = vec3f(xf);
vec3f shaded = .1f*cd; // bit of ambient
if (numLights==0) shaded = cd; // in that case, fully ambient
for (int lightID=0; lightID<numLights; ++lightID) {
const vec3f L = normalize(lp.lights[lightID].pos-pos);
const float ld = length(lp.lights[lightID].pos-pos);
shaded += cd * (.9f*dot(N,L) / (ld*ld) * lp.lights[lightID].intensity);
}
color += (1.f-color.w)*xf.w*vec4f(shaded, 1.f);
}
else {
color += (1.f-color.w)*xf.w*vec4f(vec3f(xf), 1.f);
}
if (color.w >= 0.99f) {
break;
}
}
return color;
}
// ExaBricks overload
template <bool Shading>
inline __device__
vec4f integrateDVR(ExaBrickSampler::LP sampler,
Ray ray,
float t0,
float t1,
float ils_t0,
const int numLights)
{
vec4f pixelColor(0.f);
// first, since we now traverse bricks and sample cells: convert ray to voxel space...
ray.origin = xfmPoint(lp.voxelSpaceTransform,ray.origin);
ray.direction = xfmVector(lp.voxelSpaceTransform,ray.direction);
const float dt_scale = length(vec3f(ray.direction));
ray.direction = normalize(vec3f(ray.direction));
ray.tmin = ray.tmin * dt_scale;
ray.tmax = ray.tmax * dt_scale;
auto integrate = [=,&pixelColor](const int leafID, float t0, float t1) {
const float global_dt = lp.render.dt;
const ABR &abr = lp.abrBuffer[leafID];
const float dt = global_dt * abr.finestLevelCellWidth;
int i0 = int(ceilf((t0-dt*ils_t0) / dt));
float t_i = (ils_t0 + i0) * dt;
while ((t_i-dt) >= t0) t_i = t_i-dt;
while (t_i < t0) t_i += dt;
float t_last = t0;
for (;true;t_i += dt)
{
const float t_next = min(t_i,t1);
const float t_sample = 0.5f*(min(t1,t_next)+t_last);
const float actual_dt = t_next-t_last;
t_last = t_next;
const vec3f pos = ray.origin + t_sample * ray.direction;
const int *childList = &lp.abrLeafListBuffer[abr.leafListBegin];
const int childCount = abr.leafListSize;
float sumWeightedValues = 0.f;
float sumWeights = 0.f;
for (int childID=0;childID<childCount;childID++) {
const int brickID = childList[childID];
addBasisFunctions(sampler, sumWeightedValues, sumWeights, brickID, pos);
}
float value = sumWeightedValues/sumWeights;
vec4f sample = lookupTransferFunction(value);
sample.w = 1.f - powf(1.f-sample.w, actual_dt);
pixelColor += (1.f-pixelColor.w)*sample.w*vec4f(vec3f(sample), 1.f);
if (pixelColor.w >= 0.99f) break;
if (t_next >= t1) break;
}
if (pixelColor.w >= 0.99f) {
pixelColor = vec4f(vec3f(pixelColor)*pixelColor.w,1.f);
return false; // stop iteration
}
return true; // go on
};
// Only implemented for ABR-BVH!
traverse(lp.majorantBVH,ray,integrate);
return pixelColor;
}
// ------------------------------------------------------------------
// Spatial domain iterators
// ------------------------------------------------------------------
template <typename Traversable, typename Func>
inline __device__
void traverse(Traversable traversable, Ray ray, const Func &func)
{
float alreadyIntegratedDistance = ray.tmin;
while (1) {
DomainPRD prd;
prd.t0 = prd.t1 = 0.f; // doesn't matter as long as leafID==-1
prd.domainID = -1;
ray.tmin = alreadyIntegratedDistance;
owl::traceRay(traversable, ray, prd, OPTIX_RAY_FLAG_DISABLE_ANYHIT);
if (prd.domainID < 0)
return;
if (!func(prd.domainID,prd.t0,prd.t1))
return;
alreadyIntegratedDistance = prd.t1 * (1.0000001f);
}
}
template <typename Func>
inline __device__
void traverse(const KDTreeTraversableHandle &traversable, Ray ray, const Func &func)
{
DomainPRD prd;
kd::traceRay(traversable, ray, prd, [=](const Ray &ray,
DomainPRD &prd,
int primID,
float tmin, float tmax,
KDTreeHitRec &hitRec) {
const ExaBrick &brick = optixLaunchParams.sampler.ebs.brickBuffer[primID];
const box3f bounds = brick.getBounds(); // use strict domain
float t0 = 1e30f, t1 = -1e30f;
if (boxTest(ray,bounds,t0,t1)) {
t0 = max(t0, tmin);
t1 = min(t1, tmax);
hitRec.hit = !func(primID,t0,t1);
}
});
}
template <typename Func>
inline __device__
void traverse(const GridTraversableHandle &grid, Ray ray, const Func &func)
{
#ifdef EXA_STITCH_MIRROR_EXAJET
if (grid.mirrorPlane.axis < 0) {
// (Qi) intentionally comment this line because `grid.mirrorPlane.axis` should always be positive
//
// dda3(ray,grid.traversable.dims,grid.traversable.bounds,func);
} else {
float d;
if (grid.mirrorPlane.axis == 0) {
d = (grid.mirrorPlane.offset - ray.origin.x) * rcp(ray.direction.x);
}
else if (grid.mirrorPlane.axis == 1) {
d = (grid.mirrorPlane.offset - ray.origin.y) * rcp(ray.direction.y);
}
else {
d = (grid.mirrorPlane.offset - ray.origin.z) * rcp(ray.direction.z);
}
const vec3f ori = ray.origin;
const vec3f dir = ray.direction;
const float tmin = ray.tmin;
const float tmax = ray.tmax;
unsigned i_near = signbit(ray.direction[grid.mirrorPlane.axis]);
unsigned i_far = 1^i_near;
if (d <= ray.tmin) {
if (i_far == 1) {
ray.origin = xfmPoint(grid.mirrorInvTransform,ray.origin);
ray.direction = xfmVector(grid.mirrorInvTransform,ray.direction);
}
dda3(ray,grid.traversable.dims,grid.traversable.bounds,func);
} else if (d >= ray.tmax) {
if (i_near == 1) {
ray.origin = xfmPoint(grid.mirrorInvTransform,ray.origin);
ray.direction = xfmVector(grid.mirrorInvTransform,ray.direction);
}
dda3(ray,grid.traversable.dims,grid.traversable.bounds,func);
} else {
bool goOn = false;
auto wrapper = [&goOn,func](int leafID, float t0, float t1) {
goOn = func(leafID,t0,t1);
return goOn;
};
if (i_near == 1) {
ray.origin = xfmPoint(grid.mirrorInvTransform,ori);
ray.direction = xfmVector(grid.mirrorInvTransform,dir);
}
ray.tmin = tmin;
ray.tmax = min(tmax,d);
dda3(ray,grid.traversable.dims,grid.traversable.bounds,wrapper);
if (goOn) {
ray.origin = ori;
ray.direction = dir;
if (i_far == 1) {
ray.origin = xfmPoint(grid.mirrorInvTransform,ori);
ray.direction = xfmVector(grid.mirrorInvTransform,dir);
}
ray.tmin = max(tmin,d);
ray.tmax = tmax;
dda3(ray,grid.traversable.dims,grid.traversable.bounds,func);
}
}
}
#else
dda3(ray,grid.dims,grid.bounds,func);
#endif
}
// ------------------------------------------------------------------
// Woodcock path tracer
// ------------------------------------------------------------------
inline __device__ vec3f getLe(const Sample s)
{
vec4f xf = lookupTransferFunction(s.value);
if (s.value > .99f)
//if (s.value < .2f)
return {120.f,60.f,45.f};
return 0.f;
}
enum CollisionType {
Boundary, Scattering, Emission,
};
enum ShadeMode {
Default, /* ordinary mode assigning colors from the TF */
Gridlets, /* show gridlets as checkerboard */
Teaser, /* paper teaser */
};
template <ShadeMode SM, typename Sampler>
inline __device__
void classifySample(Sampler sampler, Sample &s, vec4f &xf) {
auto& lp = optixLaunchParams;
(void)lp;
if constexpr (SM==Default) {
xf = lookupTransferFunction(s.value);
//xf = vec4f(randomColor(leafID),0.1f);
} else if constexpr (SM==Gridlets) {
xf = lookupTransferFunction(s.value);
if (s.cellID == -1) { // uelem
xf.x = 1.f; xf.y = 0.f; xf.z = 0.f;
} else {
const Gridlet &gridlet = sampler.gridletBuffer[s.primID];
vec3i imin = {
s.cellID%gridlet.dims.x,
s.cellID/gridlet.dims.x%gridlet.dims.y,
s.cellID/(gridlet.dims.x*gridlet.dims.y)
};
int col_index = imin.x % 2 == imin.y % 2;
col_index = imin.z % 2 == 0 ? col_index : !col_index;
if (col_index==0) {
xf.x = 1.f; xf.y = 1.f; xf.z = 1.f;
} else {
xf.x = 0.f; xf.y = 0.f; xf.z = 0.7f;
}
}
} else if constexpr (SM==Teaser) {
xf = lookupTransferFunction(s.value);
const vec3f rgb1(xf);
vec3f rgb2;
if (s.cellID == -1) { // uelem
rgb2 = vec3f(1,0,0);
} else {
const Gridlet &gridlet = sampler.gridletBuffer[s.primID];
vec3i imin = {
s.cellID%gridlet.dims.x,
s.cellID/gridlet.dims.x%gridlet.dims.y,
s.cellID/(gridlet.dims.x*gridlet.dims.y)
};
int col_index = imin.x % 2 == imin.y % 2;
col_index = imin.z % 2 == 0 ? col_index : !col_index;
if (col_index==0) {
rgb2.x = 1.f; rgb2.y = 1.f; rgb2.z = 1.f;
} else {
rgb2.x = 0.f; rgb2.y = 0.f; rgb2.z = 0.7f;
}
}
const vec2f cpOne(.4f,.6f);
const vec2f cpTwo(.6f,.4f);
const vec2i viewportSize = owl::getLaunchDims();
const vec2i pixelIndex = owl::getLaunchIndex();
const vec2f pixelUV(pixelIndex.x/float(viewportSize.x),
pixelIndex.y/float(viewportSize.y));
const float A = cpTwo.x-cpOne.x;
const float B = cpTwo.y-cpOne.y;
const float C1 = A*cpOne.x+B*cpOne.y;
const float C2 = A*cpTwo.x+B*cpTwo.y;
const float C = A*pixelUV.x+B*pixelUV.y;
if (C <= C1) {
xf.x = rgb1.x; xf.y = rgb1.y; xf.z = rgb1.z;
} else if (C >= C2) {
xf.x = rgb2.x; xf.y = rgb2.y; xf.z = rgb2.z;
} else {
xf.x = (rgb1.x * (C2-C) + rgb2.x * (C-C1))/(C2-C1);
xf.y = (rgb1.y * (C2-C) + rgb2.y * (C-C1))/(C2-C1);
xf.z = (rgb1.z * (C2-C) + rgb2.z * (C-C1))/(C2-C1);
}
}
}
template <ShadeMode SM, bool Shadow=false, typename Traversable, typename Sampler>
inline __device__
void sampleInteraction(const Traversable &traversable,
Ray ray,
const Sampler &sampler,
CollisionType &type, /* scattering,emission,... */
vec3f &pos, /* position of interaction */
float &Tr, /* transmission samples [0,1] */
vec3f &Le, /* emitted radiance */
vec4f &xf,
Random &random)
{
auto& lp = optixLaunchParams;
// first, since we now traverse bricks and sample cells: convert ray to voxel space...
ray.origin = xfmPoint(lp.voxelSpaceTransform,ray.origin);
ray.direction = xfmVector(lp.voxelSpaceTransform,ray.direction);
const float dt_scale = length(vec3f(ray.direction));
ray.direction = normalize(vec3f(ray.direction));
ray.tmin = ray.tmin * dt_scale;
ray.tmax = ray.tmax * dt_scale;
Le = 0.f;
type = Boundary;
Tr = 1.f;
auto woodcockFunc = [&](const int leafID, float t0, float t1) {
const float majorant = optixLaunchParams.maxOpacities[leafID];
float t = t0;
#define CACHING 1
#ifdef CACHING
int primID = -1;
#endif
while (1) { // Delta tracking loop
if (majorant <= 0.f)
break;
t -= logf(1.f-random())/(majorant*lp.transferFunc.opacityScale);
if (t >= t1) {
break;
}
#ifdef CACHING
pos = ray.origin+ray.direction*t;
Sample s = testSample(sampler,pos,primID);
if (s.primID < 0) {
SpatialDomain dom{t0,t1,leafID};
s = sample(sampler,dom,pos);
}
if (s.primID < 0)
continue;
// remember for next time!
if (s.cellID != -1) // only girdlets for now
primID = s.primID;
#else
SpatialDomain dom{t0,t1,leafID};
pos = ray.origin+ray.direction*t;
Sample s = sample(sampler,dom,pos);
if (s.primID < 0)
continue;
#endif
classifySample<SM>(sampler,s,xf);
// xf = vec4f(randomColor(leafID), majorant);
float u = random();
float sigmaT = xf.w;
if (sigmaT*lp.transferFunc.opacityScale >= u * majorant) {
Tr = 0.f;
type = Scattering;
return false;
}
}
return true;
};
auto ratioTrackingFunc = [&](const int leafID, float t0, float t1) {
const float majorant = optixLaunchParams.maxOpacities[leafID];
float t = t0;
#define CACHING 1
#ifdef CACHING
int primID = -1;
#endif
while (1) { // Delta tracking loop
if (majorant <= 0.f)
break;
t -= logf(1.f-random())/(majorant*lp.transferFunc.opacityScale);
if (t >= t1) {
break;
}
#ifdef CACHING
pos = ray.origin+ray.direction*t;
Sample s = testSample(sampler,pos,primID);
if (s.primID < 0) {
SpatialDomain dom{t0,t1,leafID};
s = sample(sampler,dom,pos);
}
if (s.primID < 0)
continue;
// remember for next time!
if (s.cellID != -1) // only girdlets for now
primID = s.primID;
#else
SpatialDomain dom{t0,t1,leafID};
pos = ray.origin+ray.direction*t;
Sample s = sample(sampler,dom,pos);
if (s.primID < 0)
continue;
#endif
classifySample<SM>(sampler,s,xf);
float sigmaT = xf.w;
Tr *= 1.f-(sigmaT*lp.transferFunc.opacityScale)/majorant;
if (Tr <= 0.f) {
type = Scattering;
return false;
}
}
return true;
};
if (Shadow)
traverse(traversable,ray,ratioTrackingFunc);
//traverse(traversable,ray,woodcockFunc);
else
traverse(traversable,ray,woodcockFunc);
// TODO: instead of transforming this back, keep both the world space
// and voxel space rays around, and cmpute pos = ray.ori+t*ray.dir in
// world space; I opted not to for the moment b/c it's a it confusing
// with the above almbda, and which params it has access to and what
// they mean, but eventually, we should do it this way because it's
// way cleaner/probably faster
pos = xfmPoint(rcp(lp.voxelSpaceTransform),pos);
}
template <ShadeMode SM, typename Traversable, typename Sampler>
inline __device__
vec3f sampleLight(const Traversable &traversable,
const vec3f pos,
Sampler sampler,
Random &random,
int numLights)
{
auto &lp = optixLaunchParams;
int lightID = uniformSampleOneLight(random,numLights);
vec3f lightDir = lp.lights[lightID].pos-pos;
const float ld = length(xfmVector(lp.lightSpaceTransform,lightDir));
const float ldWorld = length(lightDir);
// if (debug()) printf("lightDir: (%f,%f,%f), ld: %f\n",lightDir.x,lightDir.y,lightDir.z,ld);
lightDir = normalize(lightDir);
Ray ray;
ray.origin = pos;
ray.direction = lightDir;
ray.tmax = ldWorld;
float t00 = 1e30f, t11 = -1e30f;
boxTest(ray,lp.worldSpaceBounds,t00,t11);
for (int i=0; i<CLIP_PLANES_MAX; ++i) {
const bool clipPlaneEnabled = lp.clipPlanes[i].enabled;
Plane plane{lp.clipPlanes[i].N,lp.clipPlanes[i].d};
bool backFace=false;
float plane_t = FLT_MAX;
if (clipPlaneEnabled) {
plane_t = intersect(ray,plane,backFace);
if (plane_t > t00 && !backFace) t00 = max(t00,plane_t);
if (plane_t < t11 && backFace) t11 = min(plane_t,t11);
}
}
ray.tmax = t11;
MeshPRD meshPRD{-1,-1.f,{0.f},{0.f}};
if (lp.meshBVH) {
owl::traceRay(lp.meshBVH,ray,meshPRD,
OPTIX_RAY_FLAG_DISABLE_ANYHIT);
if (meshPRD.primID >= 0) {
ray.tmax = min(ray.tmax,meshPRD.t_hit);
}
}
vec3f Le;
CollisionType ctype;
vec3f newPos;
float Tr;
vec4f xf = 0.f; // albedo and extinction coefficient (ignored)
sampleInteraction<SM,true>(traversable,
ray,
sampler,
ctype,
newPos,
Tr,
Le,
xf,
random);
if (ctype==Boundary && meshPRD.primID >= 0) {
return max(0.f,dot(meshPRD.Ng,lightDir)) * Tr / (ld*ld) * lp.lights[lightID].intensity;
} else {
return Tr / (ld*ld) * lp.lights[lightID].intensity;
}
}
// ------------------------------------------------------------------
// Lambertian BRDF
// ------------------------------------------------------------------
__device__ inline
vec3f cosine_sample_hemisphere(float u1, float u2)
{
float r = sqrtf(u1);
float theta = 2.f*M_PI * u2;
float x = r * cosf(theta);
float y = r * sinf(theta);
float z = sqrtf(1.f-u1);
return {x,y,z};
}
__device__ inline
void lambertianSample(const vec3f &N, const vec3f &wo, vec3f &wi, float &pdf, Random &random)
{
vec3f u, v, w = N;
make_orthonormal_basis(u, v, w);
vec3f sp = cosine_sample_hemisphere(random(), random());
wi = normalize(vec3f(sp.x*u+sp.y*v+sp.z*w));
pdf = dot(N,wi) * (1.f/M_PI);
}
// ------------------------------------------------------------------
// HG phase function
// ------------------------------------------------------------------
__device__ inline
float henyeyGreensteinTr(const vec3f &wo, const vec3f &wi, float g)
{
const float cost = dot(wo, wi);
const float denom = 1.f + g*g + 2.f*g*cost;
return (1.f/(4.f*M_PI)) * (1.f-g*g) / (denom*sqrtf(denom));
}
__device__ inline
float henyeyGreensteinSample(const vec3f &wo, vec3f &wi, float &pdf, float g, Random &random)
{
const bool gIsNotZero = fabsf(g) >= FLT_EPSILON;
const float u1 = random();
const float u2 = random();
const float a = gIsNotZero ? (1.f-g*g) / (1.f-g + 2.f*g*u1) : 0.f;
const float cost = gIsNotZero ? (1.f + g*g - a*a) / (2.f*g) : 1.f - 2.f*u1;
const float sint = sqrtf(fmaxf(0.f, 1.f-cost*cost));
const float phi = 2.f*M_PI*u2;
vec3f u, v, w = wo;
make_orthonormal_basis(u, v, w);
wi = sint * cosf(phi) * u + sint * sinf(phi) * v + cost * -w;
pdf = 1.f;
return henyeyGreensteinTr(-w, wi, g);
}
// ------------------------------------------------------------------
// Multi-scattering path tracing integration function
// ------------------------------------------------------------------
template <ShadeMode SM, typename Traversable, typename Sampler>
inline __device__
vec4f pathTracingIntegrate(const Traversable &traversable,
Ray ray,
const Sampler &sampler,
Random &random,
const vec4f bgColor,
int numLights)
{
auto& lp = optixLaunchParams;