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Fixed NEE with isosurfaces.
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@chrismile
chrismile committed Dec 7, 2023
1 parent 678c9f6 commit cdb47ad
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Showing 3 changed files with 165 additions and 43 deletions.
11 changes: 10 additions & 1 deletion Data/Shaders/VPT/DeltaTracking.glsl
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Original file line number Diff line number Diff line change
Expand Up @@ -46,11 +46,19 @@ vec3 deltaTrackingSpectral(vec3 x, vec3 w, out ScatterEvent firstEvent) {
float PA = maxComponent(absorptionAlbedo * parameters.extinction);
float PS = maxComponent(scatteringAlbedo * parameters.extinction);

int i = 0;
float tMin, tMax;
if (rayBoxIntersect(parameters.boxMin, parameters.boxMax, x, w, tMin, tMax)) {
x += w * tMin;
float d = tMax - tMin;
while (true) {
#ifdef USE_ISOSURFACES
i++;
if (i == 1000) {
return vec3(0.0, 1.0, 0.0);
}
#endif

float t = -log(max(0.0000000001, 1 - random()))/majorant;

if (t > d) {
Expand Down Expand Up @@ -214,11 +222,12 @@ vec3 deltaTracking(
float transmittance = 1.0;

while (true) {
#ifdef USE_ISOSURFACES
i++;
if (i == 1000) {
//debugPrintfEXT("HERE");
return vec3(0.0, 1.0, 0.0);
}
#endif
#ifdef COMPUTE_SCATTER_RAY_ABSORPTION_MOMENTS
float absorbance = -log(transmittance);
if (absorbance > ABSORBANCE_MAX_VALUE) {
Expand Down
185 changes: 149 additions & 36 deletions Data/Shaders/VPT/NextEventTracking.glsl
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Original file line number Diff line number Diff line change
Expand Up @@ -25,7 +25,6 @@
// Pathtracing with Delta tracking and Spectral tracking.
#if defined(USE_NEXT_EVENT_TRACKING) || defined(USE_NEXT_EVENT_TRACKING_SPECTRAL)
float calculateTransmittance(vec3 x, vec3 w) {

float majorant = parameters.extinction.x;
float absorptionAlbedo = 1.0 - parameters.scatteringAlbedo.x;
float scatteringAlbedo = parameters.scatteringAlbedo.x;
Expand All @@ -35,6 +34,11 @@ float calculateTransmittance(vec3 x, vec3 w) {
float transmittance = 1.0;
float rr_factor = 1.;

#ifdef USE_ISOSURFACES
float lastScalarSign, currentScalarSign;
bool isFirstPoint = true;
#endif

float tMin, tMax;
if (rayBoxIntersect(parameters.boxMin, parameters.boxMax, x, w, tMin, tMax)) {
x += w * tMin;
Expand All @@ -59,15 +63,44 @@ float calculateTransmittance(vec3 x, vec3 w) {
}
}*/

x += w * t;
vec3 xNew = x + w * t;

#ifdef USE_TRANSFER_FUNCTION
vec4 densityEmission = sampleCloudDensityEmission(x);
vec4 densityEmission = sampleCloudDensityEmission(xNew);
float density = densityEmission.a;
#else
float density = sampleCloud(x);
float density = sampleCloud(xNew);
#endif

#ifdef USE_ISOSURFACES
//#if defined(ISOSURFACE_TYPE_DENSITY) && !defined(USE_TRANSFER_FUNCTION)
// float scalarValue = density;
//#else
// float scalarValue = sampleCloudDirect(xNew);
//#endif
const int isoSubdivs = 2;
bool foundHit = false;
for (int subdiv = 0; subdiv < isoSubdivs; subdiv++) {
vec3 x0 = mix(x, xNew, float(subdiv) / float(isoSubdivs));
vec3 x1 = mix(x, xNew, float(subdiv + 1) / float(isoSubdivs));
float scalarValue = sampleCloudDirect(x1);

currentScalarSign = sign(scalarValue - parameters.isoValue);
if (isFirstPoint) {
isFirstPoint = false;
lastScalarSign = currentScalarSign;
}

if (lastScalarSign != currentScalarSign) {
refineIsoSurfaceHit(x1, x0, currentScalarSign);
x = x1;
return 0;
}
}
#endif

x = xNew;

float sigma_a = PA * density;
float sigma_s = PS * density;
float sigma_n = majorant - parameters.extinction.x * density;
Expand Down Expand Up @@ -101,6 +134,10 @@ vec3 nextEventTrackingSpectral(vec3 x, vec3 w, out ScatterEvent firstEvent, bool
float majorant = maxComponent(parameters.extinction);

vec3 weights = vec3(1, 1, 1);
#ifdef USE_ISOSURFACES
float lastScalarSign, currentScalarSign;
bool isFirstPoint = true;
#endif

vec3 absorptionAlbedo = vec3(1, 1, 1) - parameters.scatteringAlbedo;
vec3 scatteringAlbedo = parameters.scatteringAlbedo;
Expand All @@ -110,30 +147,75 @@ vec3 nextEventTrackingSpectral(vec3 x, vec3 w, out ScatterEvent firstEvent, bool
vec3 color = vec3(0);
float bw_phase = 1.;

int i = 0;
float tMin, tMax;
if (rayBoxIntersect(parameters.boxMin, parameters.boxMax, x, w, tMin, tMax)) {
x += w * tMin;
float d = tMax - tMin;
while (true) {
#ifdef USE_ISOSURFACES
i++;
if (i == 1000) {
return vec3(0.0, 1.0, 0.0);
}
#endif

float t = -log(max(0.0000000001, 1 - random()))/majorant;

if (t > d) {
break;
}

x += w * t;
vec3 xNew = x + w * t;

#ifdef USE_TRANSFER_FUNCTION
vec4 scatter_density = sampleCloudColorAndDensity(x);
float density = scatter_density.a;
scatteringAlbedo = scatter_density.rgb;
vec4 densityEmission = sampleCloudDensityEmission(x);
float density = densityEmission.a;
scatteringAlbedo = densityEmission.rgb;
absorptionAlbedo = vec3(1) - scatteringAlbedo;
float PA = maxComponent(absorptionAlbedo * parameters.extinction);
float PS = maxComponent(scatteringAlbedo * parameters.extinction);
#else
float density = sampleCloud(x);
float density = sampleCloud(xNew);
#endif

#ifdef USE_ISOSURFACES
//#if defined(ISOSURFACE_TYPE_DENSITY) && !defined(USE_TRANSFER_FUNCTION)
// float scalarValue = density;
//#else
// float scalarValue = sampleCloudDirect(xNew);
//#endif
const int isoSubdivs = 2;
bool foundHit = false;
for (int subdiv = 0; subdiv < isoSubdivs; subdiv++) {
vec3 x0 = mix(x, xNew, float(subdiv) / float(isoSubdivs));
vec3 x1 = mix(x, xNew, float(subdiv + 1) / float(isoSubdivs));
float scalarValue = sampleCloudDirect(x1);

currentScalarSign = sign(scalarValue - parameters.isoValue);
if (isFirstPoint) {
isFirstPoint = false;
lastScalarSign = currentScalarSign;
}

if (lastScalarSign != currentScalarSign) {
refineIsoSurfaceHit(x1, x0, currentScalarSign);
x = x1;
vec3 color = getIsoSurfaceHit(x, w);
weights *= color;
x += w * 1e-4;
isFirstPoint = true;
if (rayBoxIntersect(parameters.boxMin, parameters.boxMax, x, w, tMin, tMax)) {
x += w * tMin;
d = tMax - tMin;
}
continue;
}
}
#endif

x = xNew;

vec3 sigma_a = absorptionAlbedo * parameters.extinction * density;
vec3 sigma_s = scatteringAlbedo * parameters.extinction * density;
vec3 sigma_n = vec3(majorant) - parameters.extinction * density;
Expand Down Expand Up @@ -171,11 +253,18 @@ vec3 nextEventTrackingSpectral(vec3 x, vec3 w, out ScatterEvent firstEvent, bool
//return color;
#ifdef USE_EMISSION
vec3 emission = sampleEmission(x);
#ifdef USE_ISOSURFACES
return color + weights * emission;
#else
return color + emission;
#endif
#else
#ifdef USE_TRANSFER_FUNCTION
vec4 emission_density = sampleCloud(x);
return emission_density.rgb * parameters.emissionStrength;
#ifdef USE_ISOSURFACES
return weights * densityEmission.rgb * parameters.emissionStrength;
#else
return densityEmission.rgb * parameters.emissionStrength;
#endif
#endif
return color; // weights * sigma_a / (majorant * Pa) * L_e; // 0 - No emission
#endif
Expand Down Expand Up @@ -256,13 +345,21 @@ vec3 nextEventTracking(vec3 x, vec3 w, out ScatterEvent firstEvent, bool onlyFir
float bw_phase = 1.;
vec3 color = vec3(0.);

int i = 0;
float tMin, tMax;
if (rayBoxIntersect(parameters.boxMin, parameters.boxMax, x, w, tMin, tMax)) {
x += w * tMin;
float d = tMax - tMin;
float pdf_x = 1;

while (true) {
#ifdef USE_ISOSURFACES
i++;
if (i == 1000) {
return vec3(0.0, 1.0, 0.0);
}
#endif

float t = -log(max(0.0000000001, 1 - random()))/majorant;

if (t > d) {
Expand All @@ -279,29 +376,40 @@ vec3 nextEventTracking(vec3 x, vec3 w, out ScatterEvent firstEvent, bool onlyFir
#endif

#ifdef USE_ISOSURFACES
#if defined(ISOSURFACE_TYPE_DENSITY) && !defined(USE_TRANSFER_FUNCTION)
float scalarValue = density;
#else
float scalarValue = sampleCloudDirect(xNew);
#endif
currentScalarSign = sign(scalarValue - parameters.isoValue);
if (isFirstPoint) {
isFirstPoint = false;
lastScalarSign = currentScalarSign;
}
//#if defined(ISOSURFACE_TYPE_DENSITY) && !defined(USE_TRANSFER_FUNCTION)
// float scalarValue = density;
//#else
// float scalarValue = sampleCloudDirect(xNew);
//#endif
const int isoSubdivs = 2;
bool foundHit = false;
for (int subdiv = 0; subdiv < isoSubdivs; subdiv++) {
vec3 x0 = mix(x, xNew, float(subdiv) / float(isoSubdivs));
vec3 x1 = mix(x, xNew, float(subdiv + 1) / float(isoSubdivs));
float scalarValue = sampleCloudDirect(x1);

currentScalarSign = sign(scalarValue - parameters.isoValue);
if (isFirstPoint) {
isFirstPoint = false;
lastScalarSign = currentScalarSign;
}

if (lastScalarSign != currentScalarSign) {
vec3 isosurfaceHitPoint = xNew;
refineIsoSurfaceHit(isosurfaceHitPoint, x, currentScalarSign);
vec3 color = getIsoSurfaceHit(isosurfaceHitPoint, w);
weights *= color;
x = isosurfaceHitPoint;
x += w * 1e-4;
isFirstPoint = true;
if (rayBoxIntersect(parameters.boxMin, parameters.boxMax, x, w, tMin, tMax)) {
x += w * tMin;
d = tMax - tMin;
if (lastScalarSign != currentScalarSign) {
refineIsoSurfaceHit(x1, x0, currentScalarSign);
x = x1;
vec3 color = getIsoSurfaceHit(x, w);
weights *= color;
x += w * 1e-4;
isFirstPoint = true;
if (rayBoxIntersect(parameters.boxMin, parameters.boxMax, x, w, tMin, tMax)) {
x += w * tMin;
d = tMax - tMin;
}
foundHit = true;
break;
}
}
if (foundHit) {
continue;
}
#endif
Expand Down Expand Up @@ -341,9 +449,9 @@ vec3 nextEventTracking(vec3 x, vec3 w, out ScatterEvent firstEvent, bool onlyFir
#else
#ifdef USE_TRANSFER_FUNCTION
#ifdef USE_ISOSURFACES
return weights * parameters.emissionStrength * densityEmission.rgb;
return color + weights * parameters.emissionStrength * densityEmission.rgb;
#else
return parameters.emissionStrength * densityEmission.rgb;
return color + parameters.emissionStrength * densityEmission.rgb;
#endif
#endif
return color; // weights * sigma_a / (majorant * Pa) * L_e; // 0 - No emission
Expand Down Expand Up @@ -379,9 +487,10 @@ vec3 nextEventTracking(vec3 x, vec3 w, out ScatterEvent firstEvent, bool onlyFir
w = next_w;
//transmittance *= pdf_eval / pdf_w;

bw_phase = pdf_w * pdf_w / (pdf_w * pdf_w + pdf_phase_nee * pdf_phase_nee);
bw_phase *= pdf_w * pdf_w / (pdf_w * pdf_w + pdf_phase_nee * pdf_phase_nee);
float bw_nee = pdf_nee * pdf_nee / (pdf_nee * pdf_nee + pdf_nee_phase * pdf_nee_phase);

// pdf_nee**2 / (pdf_nee * pdf_nee + pdf_nee_phase * pdf_nee_phase) * pdf_nee_phase**2
vec3 colorNew = bw_nee * transmittance *
calculateTransmittance(x,nee_w) *
(sampleSkybox(nee_w) + sampleLight(nee_w)) * pdf_nee_phase / pdf_nee;
Expand All @@ -407,7 +516,11 @@ vec3 nextEventTracking(vec3 x, vec3 w, out ScatterEvent firstEvent, bool onlyFir
if (!firstEvent.hasValue){
//color += sampleSkybox(w) + sampleLight(w);
}
#ifdef USE_ISOSURFACES
return color + weights * bw_phase * transmittance * (sampleSkybox(w) + sampleLight(w));
#else
return color + bw_phase * transmittance * (sampleSkybox(w) + sampleLight(w));
return transmittance * (sampleSkybox(w) + sampleLight(w));
#endif
//return transmittance * (sampleSkybox(w) + sampleLight(w));
}
#endif
12 changes: 6 additions & 6 deletions Data/Shaders/VPT/VptUtils.glsl
View file
Original file line number Diff line number Diff line change
Expand Up @@ -607,18 +607,18 @@ vec3 computeGradient(vec3 texCoords) {
(textureOffset(gridImage, texCoords, ivec3(0, 0, -1)).r
- textureOffset(gridImage, texCoords, ivec3(0, 0, 1)).r) * 0.5 / dz;
#else
const float dx = parameters.voxelTexelSize.x * 0.01;
const float dy = parameters.voxelTexelSize.y * 0.01;
const float dz = parameters.voxelTexelSize.z * 0.01;
const float dx = parameters.voxelTexelSize.x * 1;
const float dy = parameters.voxelTexelSize.y * 1;
const float dz = parameters.voxelTexelSize.z * 1;
float gradX =
(texture(gridImage, texCoords - vec3(dx, 0.0, 0.0)).r
- texture(gridImage, texCoords + vec3(dx, 0.0, 0.0)).r) * 0.5 / dx;
- texture(gridImage, texCoords + vec3(dx, 0.0, 0.0)).r) * 0.5;
float gradY =
(texture(gridImage, texCoords - vec3(0.0, dy, 0.0)).r
- texture(gridImage, texCoords + vec3(0.0, dy, 0.0)).r) * 0.5 / dy;
- texture(gridImage, texCoords + vec3(0.0, dy, 0.0)).r) * 0.5;
float gradZ =
(texture(gridImage, texCoords - vec3(0.0, 0.0, dz)).r
- texture(gridImage, texCoords + vec3(0.0, 0.0, dz)).r) * 0.5 / dz;
- texture(gridImage, texCoords + vec3(0.0, 0.0, dz)).r) * 0.5;
#endif

vec3 grad = vec3(gradX, gradY, gradZ);
Expand Down

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