dethphysics/planoInclinado.c

   1 //headers
   2 #include <SDL/SDL.h>
   3 #include <SDL/SDL_opengl.h>
   4 #include <stdio.h>
   5 #include <math.h>
   6
   7 //screen main attributes
   8 const int SCREEN_W = 800;
   9 const int SCREEN_H = 600;
  10 const int SCREEN_BPP = 32;
  11
  12 const float PI = 3.1416;
  13
  14 int DRAW_W = 800*3/4;
  15 int DRAW_H = 600*3/4;
  16
  17 int init_GL()
  18 {
  19     //set clear color
  20     glClearColor( 0, 0, 0, 0 );
  21
  22     //set the viewport
  23     glViewport(0, 0, SCREEN_W, SCREEN_H);
  24
  25     //set projection
  26     glMatrixMode( GL_PROJECTION );
  27     glLoadIdentity();
  28     glOrtho( 0, SCREEN_W, SCREEN_H, 0, -1, 1 );
  29
  30     //Initialize modelview matrix
  31     glMatrixMode( GL_MODELVIEW );
  32     glLoadIdentity();
  33
  34     //translada hacia el fondo
  35     glTranslatef( DRAW_W/8, DRAW_H, 0.0f );
  36     //rota en x 180 grados
  37     glRotatef(180,1,0,0);
  38     //if there was any errors
  39     if( glGetError() != GL_NO_ERROR )
  40     {
  41         return 0;
  42     }
  43
  44     //if everything initialized
  45     return 1;
  46 }
  47
  48 int init()
  49 {
  50     //initialize SDL
  51     if( SDL_Init( SDL_INIT_EVERYTHING ) < 0 )
  52     {
  53         return 0;
  54     }
  55
  56     //create Window
  57     if( SDL_SetVideoMode( SCREEN_W, SCREEN_H, SCREEN_BPP, SDL_OPENGL ) == NULL )
  58     {
  59         return 0;
  60     }
  61
  62     //initialize OpenGL
  63     if( init_GL() == 0 )
  64     {
  65         return 0;
  66     }
  67
  68     //set caption
  69     SDL_WM_SetCaption( "OpenGL Test", NULL );
  70
  71     return 1;
  72 }
  73
  74 void dibuja_plano(int x, int y)
  75 {
  76     int baseX = 150;
  77     int baseY = 150;
  78
  79     // clear the screen before drawing:
  80     glClear( GL_COLOR_BUFFER_BIT );
  81
  82     // draw the line
  83     glBegin(GL_TRIANGLES);
  84
  85                 //dibuja plano
  86                 glVertex3f( 0, 1, 0 );
  87                 glVertex3f( x, y, 0 );
  88     glVertex3f( x, 1, 0 );
  89
  90     glEnd();
  91 }
  92
  93 void dibuja_limites()
  94 {
  95   // draw the line
  96     glBegin(GL_LINES);
  97
  98                 //dibuja plano
  99                 glVertex3f( -DRAW_W/8, 0, 0 );
 100                 glVertex3f( DRAW_W, 0, 0 );
 101                 glVertex3f( DRAW_W, 0, 0 );
 102     glVertex3f( DRAW_W, DRAW_H, 0 );
 103
 104     glEnd();
 105
 106 }
 107
 108 void dibuja_cuadrado(double x, double y, int sq){
 109         float theta = atan2(y, x); //angulo del vector
 110         int magnitud = sq;                               //magnitud del vector
 111         int magnitud2 = sqrt(2)*magnitud;
 112         double a1[4], b1[4];
 113
 114         //obtengo los puntos
 115         a1[0] = magnitud*cos( theta );
 116         b1[0] = magnitud*sin( theta );
 117
 118         //obtengo los angulos
 119         theta += PI/4;
 120
 121         //obtengo los puntos
 122         a1[1] = magnitud2*cos( theta );
 123         b1[1] = magnitud2*sin( theta );
 124
 125   //obtengo los angulos
 126         theta += PI/4;
 127         //obtengo los puntos
 128         a1[2] = magnitud*cos( theta );
 129         b1[2] = magnitud*sin( theta );
 130
 131         //obtengo los puntos
 132         a1[3] = 0;
 133         b1[3] = 0;
 134
 135
 136   //dibuja cuadrado
 137   glBegin(GL_QUADS);
 138
 139         glColor3f( 1.0f, 0.0f, 0.0f ); /* Red                           */
 140   int i;
 141   for(i = 0; i < 4; i++)
 142         {
 143                 glVertex3f( a1[i] + x , b1[i] + y, 0 );
 144         }
 145         glColor3f( 1.0f,  1.0f,  1.0f ); /* White                         */
 146
 147   glEnd();
 148 }
 149
 150 void dibuja_flecha(int x1, int y1){
 151         float theta = atan2(y1, x1); //angulo del vector
 152   int magnitud = 20;//magnitud del vector
 153         float a1=0, b1 = 0;
 154         float a2=0, b2 = 0;
 155
 156         //valores del vector flecha
 157         //obtengo los angulos en radianes
 158         float phi1 = theta + 210;
 159         float phi2 = theta - 210;
 160
 161         //obtengo los puntos y le sumo el valor del punto P(x1,y1)
 162         //para obtener una representacion particular
 163         a1 = magnitud*cos( phi1 ) + x1; b1 = magnitud*sin( phi1 ) + y1;
 164         a2 = magnitud*cos( phi2 ) + x1; b2 = magnitud*sin( phi2 ) + y1;
 165
 166        //dibuja la lineas de la flecha
 167        glVertex3f ( x1, y1, 0);
 168        glVertex3f ( a1, b1, 0);
 169        glVertex3f ( x1, y1, 0);
 170        glVertex3f ( a2, b2, 0);
 171 }
 172
 173 void draw_line(int x, int y)
 174 {
 175   glBegin(GL_LINES);
 176                 //dibuja lineas
 177                 glVertex3f( x, y+30, 0 );
 178     glVertex3f( x, y, 0 );
 179     dibuja_flecha(x,y);
 180   glEnd();
 181 }
 182
 183 int main(int argc, char *argv[])
 184 {
 185     int quit = 0;
 186                 int x = 415, y= 245;
 187                 double posX=x*0.85      , posY=y*0.85;
 188     int square_size=50;
 189                 //initialize
 190     if( init() == 0 )
 191     {
 192         return 1;
 193     }
 194
 195     SDL_Surface *screen;
 196     SDL_Event event; //the event structure
 197     //while the user hasn't quit
 198     while( quit == 0 )
 199     {
 200
 201                 //if there's events to handle
 202         if( SDL_PollEvent( &event ) )
 203         {
 204             //if the user has Xed out the window
 205             if( event.type == SDL_QUIT )
 206             {
 207                 //quit the program
 208                 quit = 1;
 209             }
 210         }
 211
 212      dibuja_plano(x, y);
 213      dibuja_limites();
 214                  if( posY > 1 && posX > 1)
 215                  {
 216                         if(y > x){
 217                                 posX-= 0.1*y/x;
 218                                 posY-= 0.1;
 219                         }else{
 220                                 posX-= 0.1;
 221                                 posY-= 0.1*y/x;
 222                   }
 223                  }
 224                  dibuja_cuadrado( posX, posY, square_size );
 225      SDL_GL_SwapBuffers();
 226
 227      }
 228
 229
 230     SDL_Quit();
 231
 232     return 0;
 233 }