Modules/RayTracer/private/RayTracer.cpp

#include "MathCommon.hpp"
#include "NewPlacement.hpp"

#include "CommandLine.hpp"
#include "Module.hpp"
#include "Ray.hpp"
#include "RayTracer.hpp"
#include "TypeInfo.hpp"

#include <cstdio>

/*
 if (1) {
 const auto& points = castData.obj->mCache.TransformedPoints;
 const auto& normals = castData.obj->mCache.TransformedNormals;
 const auto trig = castData.trig;

const auto& n1 = normals[trig->mP1];
const auto& n2 = normals[trig->mP2];
const auto& n3 = normals[trig->mP3];

auto v0 = points[trig->mP1];
auto v1 = points[trig->mP2];
auto v2 = points[trig->mP3];

// Calculate barycentric coordinates
Vec3F barycentric;

// Calculate the area of the triangle
auto areaABC = (halnf) (v1 - v0).cross(v2 - v0).length();
auto areaPBC = (halnf) (v1 - castData.hitPos).cross(v2 - castData.hitPos).length();
auto areaPCA = (halnf) (v2 - castData.hitPos).cross(v0 - castData.hitPos).length();

// Calculate the barycentric coordinates
barycentric.x = areaPBC / areaABC;
barycentric.y = areaPCA / areaABC;
barycentric.z = 1.0f - barycentric.x - barycentric.y;

// Interpolate the normal using barycentric coordinates
normal = n1 * barycentric.x + n2 * barycentric.y + n3 * barycentric.z;
}
*/

using namespace tp;

ModuleManifest* sDependencies[] = {&gModuleMath, &gModuleCommandLine, &gModuleConnection, nullptr};

ModuleManifest tp::gModuleRayTracer = ModuleManifest("RayTracer", nullptr, nullptr, sDependencies);

void RayTracer::castRay(const Ray& ray, RayCastData& out, alnf far) {
  out.hit = false;

  far *= far;

  for (auto obj : mScene->mObjects) {
    for (auto trig : obj->mCache.TrigCaches) {
      if (trig->castRay(ray)) {
        // printf("Hit\n");

        auto dist = (trig->getHitPos() - ray.pos).length2();

        if (far > dist && dist > EPSILON) {
          out.trig = &trig.data();
          out.hitPos = trig->getHitPos();
          out.obj = &obj.data();
          out.hit = true;

          far = dist;
        }
      }
    }
  }
}

void RayTracer::cycle(const RayCastData& castData, LightData& out, uhalni depth) {
  if (depth) {
    depth--;

    Vec3F normal = castData.trig->getNormal();
    normal.normalize();

    const auto delta1 = castData.trig->mEdgeP1P2.unitV();
    const auto delta2 = normal.cross(delta1);

    for (auto idx : Range(mSettings.spray)) {
      RayCastData materialCastData;
      LightData lightData;

      auto d1 = ((halnf) randomFloat() - 0.5f) * 2;
      auto d2 = ((halnf) randomFloat() - 0.5f) * 2;

      auto sprayNormal = (normal + delta1 * d1 + delta2 * d2).normalize();

      castRay({sprayNormal, castData.hitPos}, materialCastData, mScene->mCamera.getFar());
      if (materialCastData.hit) {
        cycle(materialCastData, lightData, depth);
        out.intensity += lightData.intensity * 0.2;
      }
    }
  }

  // cast for light
  for (auto light : mScene->mLights) {
    RayCastData lightCastData;
    auto dir = light->pos - castData.hitPos;
    auto length = (halnf) dir.length();

    Ray lightRay = {dir.unitV(), castData.hitPos};

    if (lightRay.dir.dot(castData.trig->mNormal) < 0) {
      continue;
    }
    castRay(lightRay, lightCastData, length);

    if (lightCastData.hit) {
      continue;
    }

    out.intensity += light->intensity / (length * length);
  }
}

void RayTracer::render(const Scene& scene, OutputBuffers& out, const RenderSettings& settings) {
  out.color.reserve({settings.size.x, settings.size.y});
  out.normals.reserve({settings.size.x, settings.size.y});
  out.depth.reserve({settings.size.x, settings.size.y});

  mScene = &scene;
  mSettings = settings;

  auto pos = mScene->mCamera.getPos();
  auto fov = mScene->mCamera.getFOV();
  auto height = sqrt(mScene->mCamera.getRatio());
  auto width = 1.f / height;
  auto forward = mScene->mCamera.getForward();
  auto up = mScene->mCamera.getUp();
  auto right = forward.cross(up);
  auto planeCenter = pos + (forward * halnf(width / (2.f * tan(fov / 2.f))));
  auto planeCenterOffset = (up * (halnf) height / 2.f) - (right * (halnf) width / 2.f);

  auto planeLeftTop = planeCenter + planeCenterOffset;

  RayCastData castData;

  Ray ray = {
      {0, 0, 0},
      pos
  };

  Vec3F iterPoint = {0, 0, 0};
  Vec3F deltaX = right * halnf(width / (alnf) mSettings.size.x);
  Vec3F deltaY = up * halnf(-height / (alnf) mSettings.size.y);

  ualni maxIterations = mSettings.size.x * mSettings.size.y;
  ualni currIter = 0;

  halnf maxDepth = 0;
  halnf minDepth = mScene->mCamera.getFar();

  for (auto i = 0; i < mSettings.size.x; i++) {
    for (auto j = 0; j < mSettings.size.y; j++) {
      iterPoint = planeLeftTop + ((deltaX * (halnf) i) + (deltaY * (halnf) j));
      ray.dir = (iterPoint - pos).unitV();

      castRay(ray, castData, mScene->mCamera.getFar());

      if (castData.hit) {
        LightData lightData;
        cycle(castData, lightData, mSettings.depth);

        const auto normal = castData.trig->getNormal();
        const auto depth = (halnf) (castData.hitPos - ray.pos).length();

        lightData.intensity = clamp(lightData.intensity, 0.f, 1.f);
        RGBA col = {lightData.intensity, lightData.intensity, lightData.intensity, 1.f};

        out.color.set({i, j}, col);
        out.normals.set({i, j}, {normal.x * 0.5f + 0.5f, normal.y * 0.5f + 0.5f, normal.z * 0.5f + 0.5f, 1.f});
        out.depth.set({i, j}, {depth, depth, depth, 1.f});

        if (maxDepth < depth) {
          maxDepth = depth;
        }
        if (minDepth > depth) {
          minDepth = depth;
        }

      } else {
        out.color.set({i, j}, 0.f);
        out.normals.set({i, j}, 0.f);
        out.depth.set({i, j}, 0.f);
      }

      // auto tmp = buff.get({i, j});
      // printf(" %f, %f, %f, %f, ", tmp.r, tmp.g, tmp.b, tmp.a);

      mProgress.percentage = (halnf) currIter / (halnf) maxIterations;
      currIter++;
    }
  }

  for (auto i = 0; i < mSettings.size.x * mSettings.size.y; i++) {
    auto& col = out.depth.getBuff()[i];
    if (col.a == 1.f) {
      col.r = (col.r - minDepth) / (maxDepth - minDepth);
      col.g = col.r;
      col.b = col.r;
    }
  }
}