src/melissa.c

   1 /*
   2  *  Ng_Melissa_a1.c
   3  *  melng
   4  *
   5  *  Created by AppleMeiMei on 8/25/09.
   6  *  Copyright 2009 __MyCompanyName__. All rights reserved.
   7  *
   8  */
   9
  10 #include <stdlib.h>
  11 #include <GL/glut.h>
  12 #include <math.h>
  13 #define N 10
  14 #define PI 3.14159
  15
  16 static double x_offset = -50;
  17 static double x_speed = 1;
  18 static double y_offset;
  19 static double angle, new_y_offset;
  20 static int pause = 0;
  21 static int shape = 1;
  22
  23 void init(void)
  24 {
  25          // setup opengl state
  26          glClearColor(0,0,0,1.0);
  27          glColor3f(1,1,1);
  28 }
  29
  30
  31 // Setup the viewing transform
  32 // This setup up a display with coordiantes x axis -50 to 50, y axis -50 to 50
  33 // This callback is called anytime the window size changes (for example, you resize)
  34 // in Windows
  35 void reshape(int w, int h)
  36 {
  37    glViewport(0, 0, w, h);       // maps to window 0,0, with * height
  38    glMatrixMode(GL_PROJECTION);  // set the projection matrix (will talk about this later)
  39    glLoadIdentity();             // This clear any existing matrix
  40
  41     // This is a common approach in OpenGL  -- the world does is always the same, no matter
  42     // the window dim.  So, we need to normalize in case the width and height
  43    if (w <= h)                    // normalize by which dimensin is longer
  44       gluOrtho2D (-50.0, 50.0,
  45          -50.0*(GLfloat)h/(GLfloat)w, 50.0*(GLfloat)h/(GLfloat)w);
  46    else
  47       gluOrtho2D (-50.0*(GLfloat)w/(GLfloat)h,
  48          50.0*(GLfloat)w/(GLfloat)h, -50.0, 50.0);
  49
  50    glMatrixMode(GL_MODELVIEW);    // set model transformation
  51    glLoadIdentity();              // to be empty (will talk about this later
  52 }
  53
  54 // Draw a square about the origin
  55 void drawBox(double x_offset, double y_offset)
  56 {
  57     switch (shape)
  58         {
  59         case 1:
  60         // yellow ninja
  61         glBegin(GL_POLYGON);
  62         glColor3f(1,0,1);
  63     glVertex2f(x_offset, 1.0+y_offset);
  64     glVertex2f(0.3+x_offset, 0.3+y_offset);
  65     glVertex2f(1.0+x_offset, y_offset);
  66     glVertex2f(0.3+x_offset, -0.3+y_offset);
  67     glVertex2f(x_offset, -1.0+y_offset);
  68     glVertex2f(-0.3+x_offset, -0.3+y_offset);
  69     glVertex2f(-1.0+x_offset, y_offset);
  70     glVertex2f(-0.3+x_offset, 0.3+y_offset);
  71
  72     glEnd();
  73
  74         glFlush();
  75         break;
  76
  77         case 2:
  78         //red heart
  79     glBegin(GL_POLYGON);
  80         glColor3f(1,0,0);
  81     glVertex2f(x_offset, 0.5+y_offset);    // v1    v4 --> v1
  82     glVertex2f(0.5+x_offset, 0.75+y_offset);   // v2    ^      |
  83     glVertex2f(1.0+x_offset,y_offset);   // v3    |      v
  84     glVertex2f(x_offset, -1.0+y_offset);   // v4   v3 ---  v2
  85     glVertex2f(-1.0+x_offset, y_offset);    // v1    v4 --> v1
  86     glVertex2f(-0.5+x_offset, 0.75+y_offset);   // v2    ^      |
  87
  88     glEnd();
  89
  90     glFlush();
  91     break;
  92
  93     case 3:
  94     // blue cross
  95     glBegin(GL_POLYGON);
  96         glColor3f(0,1,1);
  97     glVertex2f(0.25+x_offset, 0.75+y_offset);    // v1    v4 --> v1
  98     glVertex2f(0.25+x_offset, 0.25+y_offset);   // v2    ^      |
  99     glVertex2f(1.0+x_offset,y_offset);   // v3    |      v
 100     glVertex2f(0.25+x_offset, -0.25+y_offset);   // v4   v3 ---  v2
 101     glVertex2f(0.25+x_offset, -0.75+y_offset);    // v1    v4 --> v1
 102     glVertex2f(-0.25+x_offset, -0.75+y_offset);   // v2    ^      |
 103     glVertex2f(-0.25+x_offset, -0.25+y_offset);    // v1    v4 --> v1
 104     glVertex2f(-0.75+x_offset, -0.25+y_offset);   // v3    |      v
 105     glVertex2f(-0.75+x_offset, 0.25+y_offset);   // v2    ^      |
 106     glVertex2f(-0.25+x_offset, 0.25+y_offset);    // v1    v4 --> v1
 107     glVertex2f(-0.25+x_offset, 0.75+y_offset);   // v3    |      v
 108
 109     glEnd();
 110
 111     glFlush();
 112     }
 113 }
 114
 115 /* Display Function */
 116 void display(void)
 117 {
 118     static int boxArray[100];
 119
 120          // Clear Color = black
 121          // Clear the buffer
 122     glClearColor(0,0,0,0);
 123     glClear(GL_COLOR_BUFFER_BIT);
 124
 125         int j;
 126         for(j=0;j<N;j++)
 127         {
 128
 129         drawBox(x_offset, y_offset);     // Draw with offset
 130     }
 131
 132         glClearColor(0,0,0,0);
 133         glClear(GL_COLOR_BUFFER_BIT);
 134
 135         angle = (double)((rand()%3001)/100.00) - 15; // to generate angles with 2 dp from -15 to 15
 136     new_y_offset = (double) tan ((double)(angle * PI / 180));  //no. of units moving along the y axis
 137
 138         y_offset += new_y_offset;        //  Advance offset
 139         x_offset += x_speed;           // x_offset will move 5 units at a time
 140
 141         drawBox(x_offset, y_offset);
 142
 143         if (x_offset >= 50) //out of the boundary
 144         {
 145         x_offset = -50; // move back to the left side of the screen
 146                 y_offset = 0;// return back to original y_offset
 147         }
 148
 149          glutSwapBuffers();   // Using double-buffer, swap the buffer to display
 150 }
 151
 152 // SETUP KEYBOARD -- this program updates the square when the user presses ' '(space))
 153 void keyboard(unsigned char key, int x, int y)
 154 {
 155    switch (key) {
 156
 157                 case ' ':    /* Call display function */
 158                 if(pause == 0)
 159                         pause = 1;
 160                         else pause = 0;
 161          break;
 162
 163                 case '1':
 164                         shape = 1; // ninja star
 165                         break;
 166
 167                 case '2':
 168                         shape = 2; // heart
 169                         break;
 170
 171                 case '3':
 172                 shape = 3; // cross
 173                         break;
 174
 175                 case 's' :
 176                   if(x_speed >0.5)
 177                   x_speed *= 0.5;
 178                   else
 179                   x_speed = 0.5;
 180                   break;
 181
 182                 case 'f':
 183                   if(x_speed < 10)
 184                   x_speed *= 2;
 185                   else
 186                   x_speed = 10;
 187                   break;
 188
 189                 case 27:  /*  Escape Key  */
 190          exit(0);
 191          break;
 192
 193       default:
 194              if(pause==0) glutPostRedisplay();
 195          break;
 196     }
 197 }
 198
 199 // Idle call back
 200 void idle()
 201 {
 202         if(pause==0) glutPostRedisplay();
 203 }
 204
 205 /*  Main Loop
 206  *  Open window with initial window size, title bar,
 207  *  RGB display mode, and handle input events.
 208  *
 209  *  We have registered a keyboard function.  The animation of the
 210  *  square is updated each time you press ' '.
 211  */
 212 int main(int argc, char** argv)
 213 {
 214    glutInit(&argc, argv);   // not necessary unless on Unix
 215    glutInitDisplayMode (GLUT_DOUBLE | GLUT_RGB);
 216    glutInitWindowSize (512, 512);
 217    glutCreateWindow ("Melissa_ng_a1");
 218    init();
 219
 220    glutReshapeFunc (reshape);       // register respace (anytime window changes)
 221    glutKeyboardFunc (keyboard);     // register keyboard (anytime keypressed)
 222    glutDisplayFunc (display);       // register display function
 223    glutIdleFunc (idle);             // reister idle function
 224    x_speed = rand()% 5;
 225    glutMainLoop();
 226
 227    return 0;
 228 }