Modules/RayTracer/applications/SceneLoad.cpp

#include "Rayt.hpp"

extern "C" {
#include "lauxlib.h"
#include "lualib.h"
}

#include "OBJ_Loader.h"

bool loadMeshes(tp::Scene& scene, const tp::String& objetsPath) {
  using namespace tp;

  objl::Loader Loader;

  if (!Loader.LoadFile(objetsPath.read())) {
    std::cout << "Failed to Load File. May have failed to find it or it was not an .obj file.\n";
    return false;
  }

  for (auto& curMesh : Loader.LoadedMeshes) {
    scene.mObjects.append(Object());

    auto object = &scene.mObjects.last();

    for (auto& vertex : curMesh.Vertices) {
      object->mTopology.Points.append(Vec3F {vertex.Position.X, vertex.Position.Y, vertex.Position.Z});
      object->mTopology.Normals.append(Vec3F {vertex.Normal.X, vertex.Normal.Y, vertex.Normal.Z});
    }

    for (int j = 0; j < curMesh.Indices.size(); j += 3) {
      int idx1 = (int) curMesh.Indices[j];
      int idx2 = (int) curMesh.Indices[j + 1];
      int idx3 = (int) curMesh.Indices[j + 2];
      object->mTopology.Indexes.append(Vec3I {idx1, idx2, idx3});
    }

    if (object->mTopology.Normals.size() != object->mTopology.Points.size()) {
      printf("Logic error loading normals\n");
    }

    object->mCache.Source = &object->mTopology;
    object->mCache.updateCache();
  }

  return scene.mObjects.size();
}

// Function to read a Lua table representing RenderSettings
int readRenderSettings(lua_State* L, tp::RayTracer::RenderSettings& settings) {
  lua_getglobal(L, "RenderSettings");
  if (!lua_istable(L, -1)) {
    printf("RenderSettings is not a table.\n");
    return 0; // Error
  }

  // Read depth field
  lua_getfield(L, -1, "depth");
  if (lua_isnumber(L, -1)) {
    settings.depth = (int) lua_tonumber(L, -1);
  } else {
    printf("RenderSettings 'depth' field is missing or not a number.\n");
    lua_pop(L, 1); // Pop the 'depth' field
    return 0;      // Error
  }
  lua_pop(L, 1); // Pop the 'depth' field

  // Read spray field
  lua_getfield(L, -1, "spray");
  if (lua_isnumber(L, -1)) {
    settings.spray = (int) lua_tonumber(L, -1);
  } else {
    printf("RenderSettings 'spray' field is missing or not a number.\n");
    lua_pop(L, 1); // Pop the 'spray' field
    return 0;      // Error
  }
  lua_pop(L, 1); // Pop the 'spray' field

  return 1; // Success
}

// Function to read a Lua table representing a light
int readLight(lua_State* L, tp::PointLight* light) {
  lua_getfield(L, -1, "pos"); // Get the "pos" field from the light table
  if (!lua_istable(L, -1)) {
    printf("Light is missing the 'pos' table.\n");
    return 0; // Error
  }
  for (int i = 0; i < 3; i++) {
    lua_rawgeti(L, -1, i + 1); // Index is 1-based in Lua
    if (!lua_isnumber(L, -1)) {
      printf("Light 'pos' field is not a number at index %d.\n", i);
      lua_pop(L, 2); // Pop both the number and the 'pos' table
      return 0;      // Error
    }
    light->pos[i] = lua_tonumber(L, -1);
    lua_pop(L, 1); // Pop the number
  }
  lua_pop(L, 1); // Pop the 'pos' table

  lua_getfield(L, -1, "intensity"); // Get the "intensity" field from the light table
  if (!lua_isnumber(L, -1)) {
    printf("Light is missing the 'intensity' field or it's not a number.\n");
    lua_pop(L, 1); // Pop the 'intensity' field
    return 0;      // Error
  }
  light->intensity = lua_tonumber(L, -1);
  lua_pop(L, 1); // Pop the 'intensity' field

  return 1; // Success
}

void loadScene(tp::Scene& scene, const tp::String& scenePath, tp::RayTracer::RenderSettings& settings) {
  lua_State* L = luaL_newstate();
  luaL_openlibs(L);

  if (luaL_dofile(L, "script.lua") != 0) {
    lua_close(L);
    printf("Cant open scene script.\n");
    return;
  }

  lua_getglobal(L, "Meshes");

  if (lua_isstring(L, -1)) {
    tp::String meshesPath = lua_tostring(L, -1);

    if (!loadMeshes(scene, meshesPath)) {
      printf("No 'meshes' loaded - check ur .obj path and validate content of .obj .\n");
      return;
    }

  } else {
    printf("No 'meshes' path given.\n");
    return;
  }

  // --- camera

  // Access Camera table
  lua_getglobal(L, "Camera");
  if (!lua_istable(L, -1)) {
    printf("Camera is not a table.\n");
    lua_close(L);
    return;
  }

  // Verify you are inside the "Camera" table
  int cameraTableIndex = lua_gettop(L); // Get the index of the "Camera" table

  // Access the "pos" field and validate it
  lua_getfield(L, cameraTableIndex, "pos");
  if (!lua_istable(L, -1) || lua_rawlen(L, -1) != 3) {
    printf("Invalid 'pos' field in Camera table.\n");
    lua_close(L);
    return;
  }

  // Read the values from the table
  float pos[3];
  for (int i = 0; i < 3; i++) {
    lua_rawgeti(L, -1, i + 1);
    if (lua_isnumber(L, -1)) {
      pos[i] = lua_tonumber(L, -1);
    } else {
      printf("Invalid 'pos' field value at index %d.\n", i + 1);
      lua_close(L);
      return;
    }
    lua_pop(L, 1);
  }

  // Access the "size_x" field and validate it
  lua_getfield(L, cameraTableIndex, "size_x");
  if (!lua_isnumber(L, -1)) {
    printf("Invalid or missing 'size_x' field in Camera table.\n");
    lua_close(L);
    return;
  }
  int size_x = lua_tointeger(L, -1);
  lua_pop(L, 1); // Pop the 'size_x' value from the stack

  // Access the "size_y" field and validate it
  lua_getfield(L, cameraTableIndex, "size_y");
  if (!lua_isnumber(L, -1)) {
    printf("Invalid or missing 'size_y' field in Camera table.\n");
    lua_close(L);
    return;
  }
  int size_y = lua_tointeger(L, -1);

  settings.size = {(tp::halnf) size_x, (tp::halnf) size_y};

  scene.mCamera.lookAtPoint({0, 0, 0}, {pos[0], pos[1], pos[2]}, {0, 0, 1});
  scene.mCamera.setFOV(3.14 / 4);
  scene.mCamera.setFar(100);
  scene.mCamera.setRatio((tp::halnf) size_y / (tp::halnf) size_x);

  // ---------- LIGHTS
  {
    lua_getglobal(L, "Lights");
    if (!lua_istable(L, -1)) {
      printf("Lights is not a table.\n");
      lua_close(L);
      return; // Error
    }

    // Read and process each light in the "Lights" table
    int numLights = lua_rawlen(L, -1); // Get the number of lights in the table
    for (int i = 1; i <= numLights; i++) {
      lua_rawgeti(L, -1, i); // Get the i-th element (light) from the table
      if (lua_istable(L, -1)) {
        tp::PointLight light;
        if (!readLight(L, &light)) {
          printf("Cant read lights data\n");
          lua_close(L);
          return; // Error
        }
        scene.mLights.append(light);
      }
      lua_pop(L, 1); // Pop the i-th light table
    }
  }

  // ----------- settings --------------
  if (!readRenderSettings(L, settings)) {
    printf("Cant Read Render Settings");
    lua_close(L);
    return; // Error
  }

  lua_close(L);
}