source: orxonox.OLD/branches/terrain.older/src/world_entities/skydome.cc @ 10619

/*
   orxonox - the future of 3D-vertical-scrollers
 
   Copyright (C) 2006 orx
 
   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 2, or (at your option)
   any later version.
 
### File Specific:
   main-programmer: hdavid, amaechler
   co-programmer: ...
*/

#include "skydome.h"

#include "util/loading/load_param.h"
#include "util/loading/factory.h"
#include "static_model.h"
#include "shader.h"

#include "network_game_manager.h"
#include "converter.h"
#include "util/loading/resource_manager.h"

#define DTOR (PI/180.0f)
#define SQR(x) (x*x)

using namespace std;


/**
 *  initializes a skybox from a XmlElement
 */
Skydome::Skydome()
{
  this->init();
}


void Skydome::init()
{
  PRINTF(0)("Skydome init\n");

  this->setClassID(CL_SKYDOME, "Skydome");
  this->toList(OM_BACKGROUND);
  this->toReflectionList();
  
  activateDome = false;

}


/**
 *  default destructor
 */
Skydome::~Skydome()
{
  PRINTF(0)("Deleting Skydome\n");

  if (glIsTexture(texture))
    glDeleteTextures(1, &texture);
}


void Skydome::setShader(Shader* shader)
{
  this->shader = shader;
}

void Skydome::setTexture(GLuint texture)
{
  this->texture = texture;
}


void Skydome::activate()
{
  this->activateDome = true;
}

void Skydome::deactivate()
{
  this->activateDome = false;
}


void Skydome::draw() const
{
  if(!activateDome)
    return;
  
  glPushAttrib(GL_ENABLE_BIT);

  glDisable(GL_LIGHTING);
  glDisable(GL_BLEND);

  glEnable(GL_TEXTURE_3D);
  glBindTexture(GL_TEXTURE_3D, texture);

  this->shader->activateShader();

  glPushMatrix();
  glTranslatef(0.0f,pRadius,0.0f);


  glBegin(GL_TRIANGLES);

  for (int i=0; i < numIndices; i++)
  {
    glColor3f(1.0f, 1.0f, 1.0f);

    glTexCoord2f(planeVertices[indices[i]].u, planeVertices[indices[i]].v);
    glVertex3f(planeVertices[indices[i]].x, planeVertices[indices[i]].y, planeVertices[indices[i]].z);
  }

  glEnd();

  glPopMatrix();

  this->shader->deactivateShader();

  glPopAttrib();
}


void Skydome::generateSkyPlane(int divisions, float planetRadius, float atmosphereRadius, float hTile, float vTile)
{
  PRINTF(0)("Generating a sky plane");

  // Make sure our vertex array is clear
  if (planeVertices)
  {
    delete planeVertices;
    planeVertices = NULL;
  }

  // Make sure our index array is clear
  if (indices)
  {
    delete indices;
    indices = NULL;
  }

  // Set the number of divisions into a valid range
  int divs = divisions;
  if (divisions < 1)
    divs = 1;

  if (divisions > 256)
    divs = 256;

  pRadius = planetRadius;

  // Initialize the Vertex and indices arrays
  numPlaneVertices = (divs + 1) * (divs + 1);   // 1 division would give 4 verts
  numIndices  = divs * divs * 2 * 3;       // 1 division would give 6 indices for 2 tris

  planeVertices = new VertexInfo[numPlaneVertices];
  memset(planeVertices, 0, sizeof(VertexInfo));

  indices = new int[numIndices];
  memset(indices, 0, sizeof(int)*numIndices);

  // Calculate some values we will need
  float plane_size = 2.0f * (float)sqrt((SQR(atmosphereRadius)-SQR(planetRadius)));
  float delta = plane_size/(float)divs;
  float tex_delta = 2.0f/(float)divs;

  // Variables we'll use during the dome's generation
  float x_dist   = 0.0f;
  float z_dist   = 0.0f;
  float x_height = 0.0f;
  float z_height = 0.0f;
  float height = 0.0f;

  VertexInfo SV; // temporary vertex

  for (int i=0;i <= divs;i++)
  {
    for (int j=0; j <= divs; j++)
    {
      x_dist = (-0.5f * plane_size) + ((float)j*delta);
      z_dist = (-0.5f * plane_size) + ((float)i*delta);

      x_height = (x_dist*x_dist) / atmosphereRadius;
      z_height = (z_dist*z_dist) / atmosphereRadius;
      height = x_height + z_height;

      SV.x = x_dist;
      SV.y = 0.0f - height;
      SV.z = z_dist;

      // Calculate the texture coordinates
      SV.u = hTile*((float)j * tex_delta*0.5f);
      SV.v = vTile*(1.0f - (float)i * tex_delta*0.5f);

      planeVertices[i*(divs+1)+j] = SV;
    }
  }

  // Calculate the indices
  int index = 0;
  for (int i=0; i < divs;i++)
  {
    for (int j=0; j < divs; j++)
    {
      int startvert = (i*(divs+1) + j);

      // tri 1
      indices[index++] = startvert;
      indices[index++] = startvert+1;
      indices[index++] = startvert+divs+1;

      // tri 2
      indices[index++] = startvert+1;
      indices[index++] = startvert+divs+2;
      indices[index++] = startvert+divs+1;
    }
  }
}