m.giller/cloudy-raytracer
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Clouds now interacting with lights, but especially sunlight is still buggy

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This commit is contained in:
Maximilian Giller 2023-01-26 05:04:30 +01:00
parent 9dd5878f31
commit 8a1ec659a2
4 changed files with 153 additions and 85 deletions
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11
fancy1.cpp
View file

@ -31,9 +31,11 @@ int main()
scene.setBackgroundColor(Color(0.529f, 0.808f, 0.922f));
// Add lights
auto mainLight = std::make_shared<SunLight>(Vector3d(-1.0f, -0.5f, -1.0f), 10.0f);
auto mainLight = std::make_shared<SunLight>(Vector3d(-1.0f, -0.5f, -1.0f), 10.0f, Color(1, 0.79f, 0.62f));
scene.add(mainLight);
scene.add(std::make_shared<AmbientLight>(0.3f));
// scene.add(std::make_shared<AmbientLight>(0.3f));
// auto light = std::make_shared<PointLight>(Vector3d(25.0f, 10.0f, 25.0f), 100.0f);
// scene.add(light);
// Add the bus
// auto busShader = std::make_shared<ToneShader>(mainLight);
@ -54,11 +56,8 @@ int main()
// Add box for volume shader
auto cloudSettings = CloudSettings();
cloudSettings.scale = 15.0f;
cloudSettings.densityIntensity = 10.0f;
cloudSettings.densityTreshold = 0.49f;
cloudSettings.densityAbsorption = 0.9f;
auto cloudShader = std::make_shared<CloudShader>(cloudSettings);
scene.add(std::make_shared<Box>(Vector3d(20.0f, 8.0f, 20.0f), Vector3d(50.0f, 5.0f, 50.0f), cloudShader));
scene.add(std::make_shared<Box>(Vector3d(20.0f, 10.0f, 20.0f), Vector3d(50.0f, 10.0f, 50.0f), cloudShader));
// build the tree
scene.buildTree();

108
shader/cloudshader.cpp
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@ -36,25 +36,28 @@ Color CloudShader::shade(const Scene &scene, const Ray &ray) const
float stepLength = cloudLength / noiseSamples;
// Step through cloud
float transmittance = 1.0f;
Color cloudColor = Color(1, 1, 1);
float transmittance = 1;
Color cloudColor = Color(0, 0, 0);
for (int i = 0; i < noiseSamples; ++i)
{
// Get sample point
Vector3d samplePoint = hitPoint + i * stepLength * ray.direction;
Vector3d lengthDirection = i * stepLength * ray.direction;
Vector3d samplePoint = hitPoint + lengthDirection;
// Get data at point
float sampleDensity = getCloudDensity(samplePoint) * stepLength;
if (sampleDensity > REFR_EPS) {
cloudColor += lightMarch(scene, samplePoint, ray);
if (sampleDensity > 0)
{
cloudColor += lightMarch(scene, samplePoint, lengthDirection) * stepLength * sampleDensity;
}
transmittance *= exp(-sampleDensity * stepLength * settings.densityAbsorption);
if (transmittance <= TRANSMITTANCE_BREAK) break; // No need to continue
transmittance *= exp(-sampleDensity * stepLength * settings.lightAbsorptionThroughCloud);
if (transmittance < TRANSMITTANCE_BREAK) break; // Cloud is effectively opaque
}
return background * transmittance + (1.0f - transmittance) * cloudColor;
return background * transmittance + cloudColor;
}
bool CloudShader::isTransparent() const
@ -76,40 +79,60 @@ float CloudShader::getCloudDensity(Vector3d point) const
// Threshold
// TODO: Smooth out!
density = std::max(0.0f, density - settings.densityTreshold) * settings.densityIntensity;
density = std::max(0.0f, density + settings.densityOffset) * settings.densityIntensity;
return density;
}
Color CloudShader::lightMarch(const Scene &scene, Vector3d position, const Ray &ray) const
Color CloudShader::lightMarch(const Scene &scene, Vector3d currentInCloudPosition, Vector3d lengthDistance) const
{
Color cloudColor;
// For alle lights
for (const auto &light: scene.lights())
{
auto illumination = light->illuminate(scene, position);
Ray ray = Ray(currentInCloudPosition - lengthDistance, normalized(lengthDistance));
ray.length = length(lengthDistance);
auto illumination = light->illuminate(scene, ray);
// Handle ambient lights
if (illumination.distance == 0.0f) {
if (illumination.distance == 0.0f)
{
cloudColor += illumination.color;
continue;
}
// Light ray
Ray lightRay;
lightRay.origin = position;
lightRay.origin = currentInCloudPosition;
lightRay.direction = illumination.direction;
lightRay.length = 0; // Starting in cloud itself
Color transparency = this->transparency(scene, lightRay, illumination.distance);
cloudColor += transparency * illumination.color;
float density = this->rayDensity(lightRay, illumination.distance);
density *= settings.lightAbsorptionTowardsLight;
// Proper light calculation
float transmittance = exp(-density) * (1 - exp(-density * 2));
float scatter = scatterFactor(normalized(lengthDistance), illumination.direction);
float factor = settings.darknessThreshold + (scatter * transmittance) * (1 - settings.darknessThreshold); // (transmittance * scatter)
cloudColor += factor * illumination.color;
}
return cloudColor;
}
Color CloudShader::transparency(const Scene &scene, const Ray &ray, float maxLength) const
{
float density = rayDensity(ray, maxLength);
float transmittance = exp(-density * settings.shadowLightAbsorption);
transmittance = 1 - (1 - transmittance) * settings.shadowIntensity;
return Color(1, 1, 1) * transmittance;
}
float CloudShader::rayDensity(const Ray &ray, float maxLength) const
{
Vector3d startPoint = ray.origin + ray.direction * (ray.length + 0.0001f);
@ -122,19 +145,20 @@ Color CloudShader::transparency(const Scene &scene, const Ray &ray, float maxLen
cloudRay.primitive = nullptr;
// Get out of cloud primitive first
if (ray.primitive != nullptr && !ray.primitive->intersect(cloudRay) || cloudRay.length == INFINITY || cloudRay.length <= 0)
if (ray.primitive != nullptr && !ray.primitive->intersect(cloudRay) || cloudRay.length == INFINITY ||
cloudRay.length <= 0)
{
// Something went wrong
return Color(1, 1, 1);
// Something went wrong => No density
return 0;
}
cloudLength = std::min(cloudRay.length, maxLength - ray.length);
// Calculate step length
int noiseSamples = settings.lightSamples;
float stepLength = cloudLength / noiseSamples;
float stepLength = cloudLength / (float) noiseSamples;
// Step through cloud
float transmittance = 1.0f;
float density = 1.0f;
for (int i = 0; i < noiseSamples; ++i)
{
// Get sample point
@ -143,11 +167,47 @@ Color CloudShader::transparency(const Scene &scene, const Ray &ray, float maxLen
// Get data at point
float sampleDensity = getCloudDensity(samplePoint) * stepLength;
transmittance *= exp(-sampleDensity * stepLength);
if (transmittance <= TRANSMITTANCE_BREAK) break; // No need to continue
density += sampleDensity * stepLength;
}
transmittance = 1 - (1 - transmittance) * settings.shadowIntensity;
// If there is length left, check if it is in the cloud recursively
if (cloudLength < maxLength - ray.length)
{
Vector3d endPoint = startPoint + (cloudLength + REFR_EPS) * ray.direction;
Ray recursiveRay = cloudRay;
recursiveRay.origin = endPoint;
recursiveRay.length = 0;
recursiveRay.primitive = nullptr;
return Color(1, 1, 1) * transmittance;
if (ray.primitive != nullptr && ray.primitive->intersect(recursiveRay) && recursiveRay.length > 0)
{
density += rayDensity(recursiveRay, maxLength - (cloudLength + REFR_EPS));
}
}
return density;
}
float CloudShader::scatterFactor(Vector3d visualRay, Vector3d illuminationRay) const
{
// The asymmetry parameter
float g = 0.7f;
// The angle between the visual and illumination rays
float cosTheta = dotProduct(visualRay, illuminationRay);
// The Dual-Lob Henyey-Greenstein function
float blend = .5;
float scatter = HenyeyGreenstein(cosTheta,g) * (1-blend) + HenyeyGreenstein(cosTheta,-g) * blend;
// Clamp the result to the range [0, 1]
scatter = std::max(std::min(scatter, 1.0f), 0.0f);
return scatter;
}
float CloudShader::HenyeyGreenstein(float cosTheta, float g) const
{
float g2 = g * g;
return (1 - g2) / (4 * 3.1415f * pow(1 + g2 - 2 * g * (cosTheta), 1.5f));
}

22
shader/cloudshader.h
View file

@ -8,18 +8,20 @@
#include "common/noise/worleynoise.h"
int const NOISE_SIZE = 128;
int const TRANSMITTANCE_BREAK = 0.005f; // If transmittance goes below this limit, the cloud is considered opaque
float const TRANSMITTANCE_BREAK = 0.005f; // If transmittance goes below this limit, the cloud is considered opaque
struct CloudSettings
{
int densitySamples = 100;
int lightSamples = 20;
int lightSamples = 100;
float scale = 10;
float densityTreshold = 0.55f;
float densityIntensity = 2.5f;
float densityAbsorption = 2;
float darknessThreshold = 0.1f;
float densityOffset = -0.55f;
float densityIntensity = 7.0f;
float darknessThreshold = 0.07f;
float shadowLightAbsorption = 2;
float shadowIntensity = 0.8f;
float lightAbsorptionTowardsLight = 0.94f;
float lightAbsorptionThroughCloud = 0.85f;
};
class CloudShader : public Shader
@ -41,7 +43,13 @@ private:
float getCloudDensity(Vector3d point) const;
Color lightMarch(const Scene &scene, Vector3d position, const Ray &ray) const;
Color lightMarch(const Scene &scene, Vector3d currentInCloudPosition, Vector3d lengthDistance) const;
float rayDensity(const Ray &ray, float maxLength) const;
float scatterFactor(Vector3d visualRay, Vector3d illuminationRay) const;
float HenyeyGreenstein(float cosTheta, float g) const;
};

7
shader/refractionshader.cpp
View file

@ -9,8 +9,11 @@ RefractionShader::RefractionShader(float indexInside, float indexOutside, Color
Color RefractionShader::shade(Scene const &scene, Ray const &ray) const
{
// Circumvent getting environment map color into the mix
if (ray.getRemainingBounces() > 0)
if (ray.getRemainingBounces() <= 0)
{
return Color(0.0f, 0.0f, 0.0f);
}
// Get the normal of the primitive which was hit
Vector3d normalVector = ray.normal;
@ -58,8 +61,6 @@ Color RefractionShader::shade(Scene const &scene, Ray const &ray) const
return hitColor * objectColor * lightRemaining;
}
return Color(0.0f, 0.0f, 0.0f);
}
float RefractionShader::remainingLightIntensity(float distanceThroughObject) const
{