/*
 * Descent 3
 * Copyright (C) 2024 Parallax Software
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#ifndef HEMICUBE_H
#define HEMICUBE_H

#include "3d.h"
#include "radiosity.h"
#include "gr.h"

struct rad_hemicube {
  matrix view_matrix;
  matrix head_matrix;
  vector view_position;
  rad_element *shooting_element;
  rad_surface *shooting_surface;

  grHardwareSurface drawing_surface;
  grViewport *vport;
  int *id_grid;
  float *depth_grid;

  float *top_array;
  float *side_array;

  int ff_res;   // Form factor resolution
  int grid_dim; // Hemicube top/side array dimension
};

struct hemicube_point {
  float sx, sy;
  float z;
};

extern rad_hemicube rad_Hemicube;
extern int Hemicube_resolution;

// Calculates the form factors for a hemicube
void CalculateFormFactorsHemiCube();

// Initializes the hemicube
void InitHemicube(int resolution);

void CloseHemicube();

// Clears the Zbuffer hemicube grid
void ClearHemicubeGrid();

// Sets the elements we're shooting from
void SetElementView(rad_element *ep);

// Sets the surface we're shooting from
void SetSurfaceView(rad_surface *ep);

// Build transformation matrix for our hemicube
void BuildTransform(vector *nu, vector *nv, vector *nn);

// Gets our view system ready for drawing
void StartHemicubeDrawing();

// Releases the view system
void EndHemicubeDrawing(int);

// Update hemicube view transformation matrix
void UpdateView(int face_id);

// Actually draws the projected polygon onto a hemicube face
void ScanRadiosityPoly(g3Point **pl, int nv, int element_id);
void DrawRadiosityPoly(int nv, g3Point **pointlist, int id);
void GetVertexOrdering(hemicube_point *t, int nv, int *vlt, int *vlb, int *vrt, int *vrb, int *bottom_y_ind);
int PrevIndex(int val, int modulus);
int NextIndex(int val, int modulus);

// Sums the delta form factors
void SumDeltas(float *ff_array, int face_id);

float GetTopFactor(int row, int col);

// Get side face cell form factor
float GetSideFactor(int row, int col);

#endif