86 lines
2.7 KiB
C++
86 lines
2.7 KiB
C++
#include "cloudshader.h"
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#include "common/noise/cloudnoise.h"
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#include "common/noise/perlinnoise.h"
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Color CloudShader::shade(const Scene &scene, const Ray &ray) const
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{
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Vector3d hitPoint = ray.origin + ray.direction * ray.length; // Potentially add epsilon
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// Collect getNoise through the cloud
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float cloudLength = 0.0f; // Length of cloud in ray direction
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// Get background color behind cloud and information about the clouds length
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Ray cloudRay = ray;
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cloudRay.origin = ray.origin + (ray.length + REFR_EPS) * ray.direction;
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cloudRay.length = INFINITY;
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cloudRay.primitive = nullptr;
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// Get out of cloud primitive first
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if (ray.primitive->intersect(cloudRay))
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{
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// Get length
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cloudLength = cloudRay.length;
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// Prepare ray for background color
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cloudRay.setRemainingBounces(cloudRay.getRemainingBounces() + 1);
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cloudRay.origin = cloudRay.origin + (cloudRay.length + REFR_EPS) * cloudRay.direction;
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cloudRay.length = INFINITY;
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cloudRay.primitive = nullptr;
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}
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Color background = scene.traceRay(cloudRay);
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if (cloudLength == 0.0f) return background; // No cloud or at edge
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// Calculate step length
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int noiseSamples = settings.densitySamples;
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float stepLength = cloudLength / noiseSamples;
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// Step through cloud
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float transmittance = 1.0f;
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for (int i = 0; i < noiseSamples; ++i)
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{
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// Get sample point
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Vector3d samplePoint = hitPoint + i * stepLength * ray.direction;
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// Get data at point
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float sampleDensity = getCloudDensity(samplePoint) * stepLength;
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transmittance *= exp(-sampleDensity * stepLength * settings.densityAbsorption);
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}
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// Add some ambient and diffuse lighting
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// cloud += scene.ambientLight() * material.ambient();
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// for (const auto &light: scene.lights())
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// {
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// Light::Illumination illumination = light->illuminate(scene, ray);
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// if (illumination.distance == 0.0f) continue; // Skip ambient light
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// float diffuse = dotProduct(normal, illumination.direction);
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// cloud += material.cloud() * illumination.cloud * diffuse;
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// }
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return background * transmittance + (1.0f - transmittance) * settings.cloudColor;
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}
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bool CloudShader::isTransparent() const
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{
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return true;
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}
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CloudShader::CloudShader(const CloudSettings &settings) : settings(settings),
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cloudNoise(CloudNoise(NOISE_SIZE))
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{
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cloudNoise.invert = true;
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}
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float CloudShader::getCloudDensity(Vector3d point) const
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{
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point /= settings.scale;
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float density = cloudNoise.getNoise(point);
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// Treshold
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density = std::max(0.0f, density - settings.densityTreshold) * settings.densityIntensity;
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return density;
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}
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