source: orxonox.OLD/orxonox/branches/shadows/src/shadow.cc @ 3715

/*

    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: David Gruetter
    co-programmer: ...
    
    
    Created by Dave, in this file shadow will be implemented in a quite sexy and
    fast way, with a lot of opengl-code, to keep it fast! The origin of the code
    comes form an example at www.frustum.org, slitly different although, so that 
    it works with Orxonox:)
    
    */
    
#include "importer/material.h"
#include "stdincl.h"
#include <stdio.h>
#include <stdarg.h>
#include <malloc.h>
#include <math.h>
#include "shadow.h"

#define SIZE    128
#define GL_CLAMP_TO_EDGE_EXT 0x812F

using namespace std;

/**
   \brief default Constructor
*/

Shadow::Shadow(OBJModel* player,Player* playerangle,float groundVertexes[])
{
    this->player=player;
    this->playerangle=playerangle;
}


/**
    \brief default destructor
*/

Shadow::~Shadow()
{
}

void Shadow::init()
{
    
    float plane_s[] ={1.0f,0.0f,0.0f,0.0f};
    float plane_t[] ={0.0f,1.0f,0.0f,0.0f};
    float plane_r[] ={0.0f,0.0f,1.0f,0.0f};
    float plane_q[] ={0.0f,0.0f,0.0f,1.0f};
    
    glClearDepth(1);
    glDepthFunc(GL_LEQUAL);
    glTexGenfv(GL_S,GL_EYE_PLANE,plane_s);
    glTexGenfv(GL_T,GL_EYE_PLANE,plane_t);
    glTexGenfv(GL_R,GL_EYE_PLANE,plane_r);
    glTexGenfv(GL_Q,GL_EYE_PLANE,plane_q);
    glTexGeni(GL_S,GL_TEXTURE_GEN_MODE,GL_EYE_LINEAR);
    glTexGeni(GL_T,GL_TEXTURE_GEN_MODE,GL_EYE_LINEAR);
    glTexGeni(GL_R,GL_TEXTURE_GEN_MODE,GL_EYE_LINEAR);
    glTexGeni(GL_Q,GL_TEXTURE_GEN_MODE,GL_EYE_LINEAR);
    
    glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MIN_FILTER,GL_LINEAR);
    glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MAG_FILTER,GL_LINEAR);
    glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_WRAP_S,GL_CLAMP_TO_EDGE_EXT);
    glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_WRAP_T,GL_CLAMP_TO_EDGE_EXT);
    glTexImage2D(GL_TEXTURE_2D,0,GL_RGB,SIZE,SIZE,0,GL_RGB,GL_UNSIGNED_BYTE,NULL);

    this->ground_id=glGenLists(1);
    glNewList(this->ground_id,GL_COMPILE);
    
    //blabla
    
    glEndList();
    
    this->player_id=glGenLists(1);
    glNewList(this->player_id,GL_COMPILE);
    
    this->player->draw();
    
    glEndList();    
    
    this->image=(unsigned char*)malloc(SIZE*SIZE*4);
    

}


void Shadow::createShadow()
{
    glViewport(0,0,2*SIZE,2*SIZE);
    glScissor(0,0,2*SIZE,2*SIZE);
    glEnable(GL_SCISSOR_TEST);
    glBindTexture(GL_TEXTURE_2D,this->shadow_id);
    
    glClearColor(1,1,1,1);
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    glOrtho(-4.2,4.2,-4.2,4.2,-100,100);
    glMatrixMode(GL_MODELVIEW);
    glLoadIdentity();
    
    gluLookAt(this->lightPos[0],this->lightPos[1],this->lightPos[2],this->playerPos[0],this->playerPos[1],this->playerPos[2],0,0,1);
    
    glColor3f(.1,.1,.1);
    glTranslatef(this->playerPos[0],this->playerPos[1],this->playerPos[2]);
    //die Variable angle ist im Player.h als public definiert!!! deshalb kann 
    //von hier aus darauf zugegriffen werden
    glRotatef(this->playerangle->angle,1.0,0.0,0.0);
    
    //Lighting has to be disabled for the shadow to become nice black respectively grey (color(.1,.1,.1))
    glDisable(GL_LIGHTING);
    glCallList(this->player_id);
    glEnable(GL_LIGHTING);
    
    glColor3f(1,1,1);
    glReadPixels(0,0,SIZE,SIZE,GL_RGB,GL_UNSIGNED_BYTE,this->image);
    blur(this->image,SIZE);
    glTexSubImage2D(GL_TEXTURE_2D,0,0,0,SIZE,SIZE,GL_RGB,GL_UNSIGNED_BYTE,this->image);
    
    glDisable(GL_SCISSOR_TEST);
    glViewport(0,0,1024,768); //Achtung: hier Aufloesung von Orxonox einstellen!
     
    
    
}


/** 
    brief updatePosition is used in the same kind as for skysphere, because
    the light has got a static orientation(parallel light), we have to always 
    add the same relative coordinates being 0,10,19 to the players position
    in order to receive the lightPosition. This is needed to calculate the Shadow!!

*/

void Shadow::updatePosition(float x,float y,float z)
{
    this->playerPos[0]=x;
    this->playerPos[1]=y;
    this->playerPos[2]=z;
    
    this->lightPos[0]=this->playerPos[0];
    this->lightPos[1]=this->playerPos[1]+10;
    this->lightPos[2]=this->playerPos[2]+19;

    
}
/**

    brief m_inverse simply inverses the *m matrix and stores the result back
    to *out. This is needed further down in the draw() method


*/

void Shadow::m_inverse(const float *m,float *out)
{
    float det;
    det=  m[0]*m[5]*m[10];
    det+= m[4]*m[9]*m[2];
    det+= m[8]*m[1]*m[6];
    det-= m[8]*m[5]*m[2];
    det-= m[4]*m[1]*m[10];
    det-= m[0]*m[9]*m[6];
    
    if(det!= 0.0)
        det=1.0/det;
    out[0]=  (m[5]*m[10]-m[9]*m[6])*det;
    out[1]= -(m[1]*m[10]-m[9]*m[2])*det;
    out[2]=  (m[1]*m[6]-m[5]*m[2])*det;
    out[3]= 0.0;
    out[4]= -(m[4]*m[10]-m[8]*m[6])*det;
    out[5]=  (m[0]*m[10]-m[8]*m[2])*det;
    out[6]= -(m[0]*m[6]-m[4]*m[2])*det;
    out[7]= 0.0;
    out[8]=  (m[4]*m[9]-m[8]*m[5])*det;
    out[9]= -(m[0]*m[9]-m[8]*m[1])*det;
    out[10]= (m[0]*m[5]-m[4]*m[1])*det;
    out[11]= 0.0;
    out[12]=- (m[12]*out[0]+m[13]*out[4]+m[14]*out[8]);
    out[13]=- (m[12]*out[1]+m[13]*out[5]+m[14]*out[9]);
    out[14]=- (m[12]*out[2]+m[13]*out[6]+m[14]*out[10]);
    out[15]= 1.0;


}

/**
    brief Method draw() is called after each tick() from the world.cc class
*/

void Shadow::draw()
{
    float m[16],im[16];
    createShadow();
    
    /*glClearColor(0,0,0,0);
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    gluPerspective(45,4.0/3.0,.5,100);
    glMatrixMode(GL_MODELVIEW);
    glLoadIdentity();
    
    gluLookAt(this->cameraPos[0],this->cameraPos[1],this->cameraPos[2],this->playerPos[0],this->playerPos[1],this->playerPos[2],0,0,1);
    */
    glEnable(GL_TEXTURE_GEN_S);
    glEnable(GL_TEXTURE_GEN_T);
    glEnable(GL_TEXTURE_GEN_R);
    glEnable(GL_TEXTURE_GEN_Q);
    glGetFloatv(GL_MODELVIEW_MATRIX,m);
    m_inverse(m,im);
    glMatrixMode(GL_TEXTURE);
    glLoadIdentity();
    glTranslatef(0.5,0.5,1.0);
    glOrtho(-1,1,-1,1,-1,1);
    
    gluLookAt(this->lightPos[0],this->lightPos[1],this->lightPos[2],this->playerPos[0],this->playerPos[1],this->playerPos[2],0,0,1);
    
    glMultMatrixf(im);
    glEnable(GL_TEXTURE_2D),
    glBindTexture(GL_TEXTURE_2D,this->shadow_id);
    glEnable(GL_BLEND);
    glBlendFunc(GL_DST_COLOR,GL_SRC_COLOR);
    glCallList(ground_id);
    glDisable(GL_BLEND);
    
    glLoadIdentity();
    glMatrixMode(GL_MODELVIEW);
    glDisable(GL_TEXTURE_GEN_S);
    glDisable(GL_TEXTURE_GEN_T);
    glDisable(GL_TEXTURE_GEN_R);
    glDisable(GL_TEXTURE_GEN_Q);
    
    
    
}



/**
    \don't ask me how this works, but it adds a blur effect to the shadow
    \for it doesn't look that edgy
    
*/
void Shadow::blur(unsigned char *in,int size)
{
    int x,y,sum,size3=size*3;
    unsigned char *out,*inp,*outp;
    out = (unsigned char *)malloc(size * size * 3);
    memset(out,255,size *size *3);
    
    inp=in+size3;
    outp=out+size3;
    for(y=1;y<size-1;y++){
        inp+=3;
        outp+=3;
        for(x=1;x<size-1;x++){
            sum=inp[-size3-3]+ inp[-size3] + inp[-size3+3]+
            inp[-3]+inp[0]+inp[3]+
            inp[size3-3]+inp[size3]+inp[size3+3];
            sum/=9;
            inp+=3;
            *outp++ =sum;
            *outp++ =sum;
            *outp++ =sum;
        }
        inp+=3;
        outp+=3;
    }
    
    memcpy(in,out,size*size*3);
    free(out);
        
            
    


}