/*
   orxonox - the future of 3D-vertical-scrollers

   Copyright (C) 2004 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: Stefan Lienard
   co-programmer: ...
*/

#include "mapped_water.h"
#include "util/loading/load_param.h"
#include "util/loading/factory.h"
#include "util/loading/resource_manager.h"
#include "state.h"


CREATE_FACTORY(MappedWater, CL_MAPPED_WATER);

/**
 * @brief constructor
 * @param root xml data
 */
MappedWater::MappedWater(const TiXmlElement* root)
{
  this->setClassID(CL_MAPPED_WATER, "MappedWater");
  this->toList(OM_ENVIRON);

  /// sets start values and parameters
  this->initParams();
  // now the standard values were loaded, if the values are specified in the .oxw file
  // loadParams will overwrite the standard values with the specified values
  if (root != NULL)
    this->loadParams(root);

  /// initialization of the textures
  this->initTextures();

  /// initialization of the shaders
  this->initShaders();
}

/**
 * @brief deltes shader and the uniform used by the camera
 */
MappedWater::~MappedWater()
{
  delete shader;
  delete cam_uni;
}

/**
 * @brief initialization of loadable parameters, sets start standard values
 */
void MappedWater::initParams()
{
  // those standardvalues will be overwritten if they're also set in the oxw file
  this->setWaterPos(0, 0, 0);
  this->setWaterSize(100, 100);
  this->setWaterUV(9);
  this->setWaterFlow(0.08);
  this->setLightPos(0, 10, 0);
  this->setWaterAngle(0);
  this->setNormalMapScale(0.25f);

  // initialization of the texture coords, speeds etc...
  // normalUV wont change anymore
  this->normalUV = this->waterUV * this->kNormalMapScale;
  // move and move2 are used for the reflection and refraction, the values are changed in tick()
  this->move = 0;
  this->move2 = this->move * this->kNormalMapScale;
}

/**
 * @brief initialization of the textures
 */
void MappedWater::initTextures()
{
  // sets parameters for the textures
  this->textureSize = 512;
  unsigned int channels = 32;
  GLenum type = GL_RGBA;

  // set up refleciton texture
  Texture reflTex(GL_TEXTURE_2D, this->textureSize, this->textureSize, channels, type);
  mat.setDiffuseMap(reflTex, 0);
  // set up refraction texture
  Texture refrTex(GL_TEXTURE_2D, this->textureSize, this->textureSize, channels, type);
  mat.setDiffuseMap(refrTex, 1);
  // load normal map
  mat.setDiffuseMap("pictures/normalmap.bmp", GL_TEXTURE_2D, 2);
  // load dudv map
  mat.setDiffuseMap("pictures/dudvmap.bmp", GL_TEXTURE_2D, 3);

  // sets texture parameters for reflection texture
  glBindTexture(GL_TEXTURE_2D, this->mat.getDiffuseTexture(0));
  glTexParameterf(GL_TEXTURE_2D,GL_TEXTURE_MIN_FILTER,GL_LINEAR);
  glTexParameterf(GL_TEXTURE_2D,GL_TEXTURE_MAG_FILTER,GL_LINEAR);
  glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
  glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
  // sets texture parameters for refraction texture
  glBindTexture(GL_TEXTURE_2D, this->mat.getDiffuseTexture(1));
  glTexParameterf(GL_TEXTURE_2D,GL_TEXTURE_MIN_FILTER,GL_LINEAR);
  glTexParameterf(GL_TEXTURE_2D,GL_TEXTURE_MAG_FILTER,GL_LINEAR);
  glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
  glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
}

/**
 * @brief initialization of the shaders
 */
void MappedWater::initShaders()
{
  // load shader files
  shader = new Shader( ResourceManager::getInstance()->getDataDir() + "/shaders/mapped_water.vert", ResourceManager::getInstance()->getDataDir() +"/shaders/mapped_water.frag");

  this->shader->activateShader();
  // Set the variable "reflection" to correspond to the first texture unit
  Shader::Uniform(shader, "reflection").set(0);
  // Set the variable "refraction" to correspond to the second texture unit
  Shader::Uniform(shader, "refraction").set(1);
  // Set the variable "normalMap" to correspond to the third texture unit
  Shader::Uniform(shader, "normalMap").set(2);
  // Set the variable "dudvMap" to correspond to the fourth texture unit
  Shader::Uniform(shader, "dudvMap").set(3);
  // Set the variable "depthMap" to correspond to the fifth texture unit
  Shader::Uniform(shader, "depthMap").set(2);
  // Give the variable "waterColor" a blue color
  Shader::Uniform(shader, "waterColor").set(0.1f, 0.2f, 0.4f, 1.0f);
  // Give the variable "lightPos" our hard coded light position
  Shader::Uniform(shader, "lightPos").set(lightPos.x, lightPos.y, lightPos.z, 1.0f);
  // uniform for the camera position
  cam_uni = new Shader::Uniform(shader, "cameraPos");

  this->shader->deactivateShader();
}

/**
 * @brief ends the refraction and saves the graphic buffer into a texture
 * @param root xml data
 */
void MappedWater::loadParams(const TiXmlElement* root)
{
  WorldEntity::loadParams(root);

  LoadParam(root, "waterpos", this, MappedWater, setWaterPos);
  LoadParam(root, "watersize", this, MappedWater, setWaterSize);
  LoadParam(root, "lightpos", this, MappedWater, setLightPos);
  LoadParam(root, "wateruv", this, MappedWater, setWaterUV);
  LoadParam(root, "waterflow", this, MappedWater, setWaterFlow);
  LoadParam(root, "normalmapscale", this, MappedWater, setNormalMapScale);
  LoadParam(root, "waterangle", this, MappedWater, setWaterAngle);
}

/**
 * @brief activates the water shader and draws a quad with four textures on it
 */
void MappedWater::draw() const
{
  glMatrixMode(GL_MODELVIEW);

  glPushMatrix();
  glTranslatef(this->waterPos.x ,0 ,this->waterPos.z);
  glRotatef(this->waterAngle, 0, 1, 0);

  mat.select();

  this->shader->activateShader();

  // reset the camera uniform to the current cam position
  Vector pos = State::getCameraNode()->getAbsCoor();
  cam_uni->set(pos.x, pos.y, pos.z, 1.0f);

  glDisable(GL_BLEND);

  glBegin(GL_QUADS);
  // The back left vertice for the water
  glMultiTexCoord2f(GL_TEXTURE0, 0, waterUV);            // Reflection texture
  glMultiTexCoord2f(GL_TEXTURE1, 0, waterUV - move);        // Refraction texture
  glMultiTexCoord2f(GL_TEXTURE2, 0, normalUV + move2);     // Normal map texture
  glMultiTexCoord2f(GL_TEXTURE3, 0, 0);                       // DUDV map texture
  glVertex3f(0, this->waterPos.y, 0);

  // The front left vertice for the water
  glMultiTexCoord2f(GL_TEXTURE0, 0, 0);                  // Reflection texture
  glMultiTexCoord2f(GL_TEXTURE1, 0, -move);           // Refraction texture
  glMultiTexCoord2f(GL_TEXTURE2, 0, move2);          // Normal map texture
  glMultiTexCoord2f(GL_TEXTURE3, 0, 0);                        // DUDV map texture
  glVertex3f(0, this->waterPos.y, this->zWidth);

  // The front right vertice for the water
  glMultiTexCoord2f(GL_TEXTURE0, waterUV, 0);             // Reflection texture
  glMultiTexCoord2f(GL_TEXTURE1, waterUV, -move);         // Refraction texture
  glMultiTexCoord2f(GL_TEXTURE2, normalUV, move2);      // Normal map texture
  glMultiTexCoord2f(GL_TEXTURE3, 0, 0);                        // DUDV map texture
  glVertex3f(this->xWidth, this->waterPos.y, this->zWidth);

  // The back right vertice for the water
  glMultiTexCoord2f(GL_TEXTURE0, waterUV, waterUV);        // Reflection texture
  glMultiTexCoord2f(GL_TEXTURE1, waterUV, waterUV - move);       // Refraction texture
  glMultiTexCoord2f(GL_TEXTURE2, normalUV, normalUV + move2);  // Normal map texture
  glMultiTexCoord2f(GL_TEXTURE3, 0, 0);                        // DUDV map texture
  glVertex3f(this->xWidth, this->waterPos.y, 0);
  glEnd();

  this->shader->deactivateShader();

  mat.unselect();

  glPopMatrix();
}

/**
 * @brief tick tack, calculates the flow of the water
 */
void MappedWater::tick(float dt)
{
  // makes the water flow
  this->move += this->waterFlow * dt;
  this->move2 = this->move * this->kNormalMapScale;
}

/**
 * @brief prepares everything to render the reflection texutre
 */
void MappedWater::activateReflection()
{
  // To create the reflection texture we just need to set the view port
  // to our texture map size, then render the current scene our camera
  // is looking at to the already allocated texture unit.  Since this
  // is a reflection of the top of the water surface we use clipping 
  // planes to only render the top of the world as a reflection.  If
  // we are below the water we don't flip the reflection but just use
  // the current view of the top as we are seeing through the water.
  // When you look through water at the surface it isn't really reflected,
  // only when looking down from above the water on the surface.

  // save viewport matrix and change the viewport size
  glPushAttrib(GL_VIEWPORT_BIT);
  glViewport(0,0, textureSize, textureSize);

  glMatrixMode(GL_MODELVIEW);
  glPushMatrix();

  // If our camera is above the water we will render the scene flipped upside down.
  // In order to line up the reflection nicely with the world we have to translate
  // the world to the position of our reflected surface, multiplied by two.
  glEnable(GL_CLIP_PLANE0);
  Vector pos = State::getCameraNode()->getAbsCoor();

  if(pos.y > waterPos.y)
  {
    // Translate the world, then flip it upside down
    glTranslatef(0, waterPos.y*2, 0);
    glScalef(1, -1, 1);

    // Since the world is updside down we need to change the culling to FRONT
    glCullFace(GL_FRONT);

    // Set our plane equation and turn clipping on
    double plane[4] = {0, 1, 0, -waterPos.y};
    glClipPlane(GL_CLIP_PLANE0, plane);
  }
  else
  {
    // If the camera is below the water we don't want to flip the world,
    // but just render it clipped so only the top is drawn.
    double plane[4] = {0, 1, 0, waterPos.y};
    glClipPlane(GL_CLIP_PLANE0, plane);
  }
}

/**
 * @brief ends the reflection and saves the graphic buffer into a texture
 */
void MappedWater::deactivateReflection()
{
  glDisable(GL_CLIP_PLANE0);
  glCullFace(GL_BACK);

  // Create the texture and store it on the video card
  mat.renderToTexture(0, GL_TEXTURE_2D, 0, 0, 0, 0, 0, textureSize, textureSize);

  glPopMatrix();
  glPopAttrib();
}

/**
 * @brief prepares everything to render the refraction texutre
 */
void MappedWater::activateRefraction()
{
  // To create the refraction and depth textures we do the same thing
  // we did for the reflection texture, except we don't need to turn
  // the world upside down.  We want to find the depth of the water,
  // not the depth of the sky and above water terrain.

  // save viewport matrix and change the viewport size
  glPushAttrib(GL_VIEWPORT_BIT);
  glViewport(0,0, textureSize, textureSize);

  glMatrixMode(GL_MODELVIEW);
  glPushMatrix();

  // If our camera is above the water we will render only the parts that
  // are under the water.  If the camera is below the water we render
  // only the stuff above the water.  Like the reflection texture, we
  // incorporate clipping planes to only render what we need.

  // If the camera is above water, render the data below the water
  glEnable(GL_CLIP_PLANE0);
  Vector pos = State::getCameraNode()->getAbsCoor();
  if(pos.y > waterPos.y)
  {
    double plane[4] = {0, -1, 0, waterPos.y}; 
    glClipPlane(GL_CLIP_PLANE0, plane);

  }
  // If the camera is below the water, only render the data above the water
  else
  {
    glCullFace(GL_FRONT);
    double plane[4] = {0, 1, 0, -waterPos.y}; 
    glClipPlane(GL_CLIP_PLANE0, plane);
  }
}

/**
 * @brief ends the refraction and saves the graphic buffer into a texture
 */
void MappedWater::deactivateRefraction()
{
  glDisable(GL_CLIP_PLANE0);
  glCullFace(GL_BACK);

  // Create the texture and store it on the video card
  mat.renderToTexture(1, GL_TEXTURE_2D, 0, 0, 0, 0, 0, textureSize, textureSize);

  glPopMatrix();
  glPopAttrib();
}