olympic.c

一些小例子

#include <windows.h>
#include <time.h>

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>
#include <sys/types.h>
#include <GL/glaux.h>

#define M_PI	3.14159265f

#define sinf(x) (float)sin((x))
#define cosf(x) (float)cos((x))
#define XSIZE   100
#define YSIZE   75

#define RINGS 5
#define BLUERING 0
#define BLACKRING 1
#define REDRING 2
#define YELLOWRING 3
#define GREENRING 4

#define BACKGROUND 8

enum {
  BLACK = 0,
  RED,
  GREEN,
  YELLOW,
  BLUE,
  MAGENTA,
  CYAN,
  WHITE
};

typedef short Point[2];

GLenum directRender;

unsigned char rgb_colors[RINGS][3];
int mapped_colors[RINGS];
float dests[RINGS][3];
float offsets[RINGS][3];
float angs[RINGS];
float rotAxis[RINGS][3];
int iters[RINGS];
GLuint theTorus;

void FillTorus(float rc, int numc, float rt, int numt)
{
  int i, j, k;
  float s, t;
  float x, y, z;
  float pi, twopi;

  pi = M_PI;
  twopi = 2 * pi;

  for (i = 0; i < numc; i++) {
    glBegin(GL_QUAD_STRIP);
    for (j = 0; j <= numt; j++) {
      for (k = 1; k >= 0; k--) {
        s = (float)((i + k) % numc + 0.5f);
        t = (float)(j % numt);

        x = cosf(t * twopi / numt) * cosf(s * twopi / numc);
        y = sinf(t * twopi / numt) * cosf(s * twopi / numc);
        z = sinf(s * twopi / numc);
        glNormal3f(x, y, z);

        x = (rt + rc * cosf(s * twopi / numc)) * cosf(t * twopi / numt);
        y = (rt + rc * cosf(s * twopi / numc)) * sinf(t * twopi / numt);
        z = rc * sinf(s * twopi / numc);
        glVertex3f(x, y, z);
      }
    }
    glEnd();
  }
}

float Clamp(int iters_left, float t)
{

  if (iters_left < 3) {
    return 0.0;
  }
  return (iters_left - 2) * t / iters_left;
}

void CALLBACK DrawScene(void)
{
  int i;

  glPushMatrix();

  glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
  gluLookAt(0, 0, 10, 0, 0, 0, 0, 1, 0);

  for (i = 0; i < RINGS; i++) {
    glColor3ubv(rgb_colors[i]);
    glPushMatrix();
    glTranslatef(dests[i][0] + offsets[i][0], 
		         dests[i][1] + offsets[i][1],
                 dests[i][2] + offsets[i][2]);
    glRotatef(angs[i], rotAxis[i][0], rotAxis[i][1], rotAxis[i][2]);
    glCallList(theTorus);
    glPopMatrix();
  }
  glPopMatrix();
  auxSwapBuffers();
}

void CALLBACK Idle(void)
{
  int i, j;
  int more = GL_FALSE;
  for (i = 0; i < RINGS; i++) {
    if (iters[i]) {
      for (j = 0; j < 3; j++) {
        offsets[i][j] = Clamp(iters[i], offsets[i][j]);
      }
      angs[i] = Clamp(iters[i], angs[i]);
      iters[i]--;
	  more = GL_TRUE;
    }
  }
  if(more) {
    DrawScene();
  } else {
	auxIdleFunc(NULL);
  }
}

float MyRand(void)
{
  return 10.0f * ( ((float) rand())/((float) RAND_MAX) - 0.5f);
}

void ReInit(void)
{
  int i;
  float deviation;

  deviation = MyRand() / 2.0f;
  deviation = deviation * deviation;
  for (i = 0; i < RINGS; i++) {
    offsets[i][0] = MyRand();
    offsets[i][1] = MyRand();
    offsets[i][2] = MyRand();
    angs[i] = 260.0f * MyRand();
    rotAxis[i][0] = MyRand();
    rotAxis[i][1] = MyRand();
    rotAxis[i][2] = MyRand();
    iters[i] = (int)(deviation * MyRand() + 60);
  }
}

void Init(void)
{
  int i;
  float top_y = 1.0f;
  float bottom_y = 0.0f;
  float top_z = 0.15f;
  float bottom_z = 0.69f;
  float spacing = 2.5f;
  static float lmodel_ambient[] = {0.0f, 0.0f, 0.0f, 0.0f};
  static float lmodel_twoside[] = {GL_FALSE};
  static float lmodel_local[] = {GL_FALSE};
  static float light0_ambient[] = {0.1f, 0.1f, 0.1f, 1.0f};
  static float light0_diffuse[] = {1.0f, 1.0f, 1.0f, 0.0f};
  static float light0_position[] = {0.8660254f, 0.5f, 1.0f, 0.0f};
  static float light0_specular[] = {1.0f, 1.0f, 1.0f, 0.0f};
  static float bevel_mat_ambient[] = {0.0f, 0.0f, 0.0f, 1.0f};
  static float bevel_mat_shininess[] = {40.0f};
  static float bevel_mat_specular[] = {1.0f, 1.0f, 1.0f, 0.0f};
  static float bevel_mat_diffuse[] = {1.0f, 0.0f, 0.0f, 0.0f};

  srand(time(NULL));
  ReInit();
  for (i = 0; i < RINGS; i++) {
    rgb_colors[i][0] = rgb_colors[i][1] = rgb_colors[i][2] = 0;
  }
  rgb_colors[BLUERING][2] = 255;
  rgb_colors[REDRING][0] = 255;
  rgb_colors[GREENRING][1] = 255;
  rgb_colors[YELLOWRING][0] = 255;
  rgb_colors[YELLOWRING][1] = 255;
  mapped_colors[BLUERING] = BLUE;
  mapped_colors[REDRING] = RED;
  mapped_colors[GREENRING] = GREEN;
  mapped_colors[YELLOWRING] = YELLOW;
  mapped_colors[BLACKRING] = BLACK;

  dests[BLUERING][0] = -spacing;
  dests[BLUERING][1] = top_y;
  dests[BLUERING][2] = top_z;

  dests[BLACKRING][0] = 0.0;
  dests[BLACKRING][1] = top_y;
  dests[BLACKRING][2] = top_z;

  dests[REDRING][0] = spacing;
  dests[REDRING][1] = top_y;
  dests[REDRING][2] = top_z;

  dests[YELLOWRING][0] = -spacing / 2.0f;
  dests[YELLOWRING][1] = bottom_y;
  dests[YELLOWRING][2] = bottom_z;

  dests[GREENRING][0] = spacing / 2.0f;
  dests[GREENRING][1] = bottom_y;
  dests[GREENRING][2] = bottom_z;

  theTorus = glGenLists(1);
  glNewList(theTorus, GL_COMPILE);
  FillTorus(0.1f, 8, 1.0f, 25);
  glEndList();

  glEnable(GL_CULL_FACE);
  glCullFace(GL_BACK);
  glEnable(GL_DEPTH_TEST);
  glClearDepth(1.0);

  glClearColor(0.5, 0.5, 0.5, 0.0);
  glLightfv(GL_LIGHT0, GL_AMBIENT, light0_ambient);
  glLightfv(GL_LIGHT0, GL_DIFFUSE, light0_diffuse);
  glLightfv(GL_LIGHT0, GL_SPECULAR, light0_specular);
  glLightfv(GL_LIGHT0, GL_POSITION, light0_position);
  glEnable(GL_LIGHT0);

  glLightModelfv(GL_LIGHT_MODEL_LOCAL_VIEWER, lmodel_local);
  glLightModelfv(GL_LIGHT_MODEL_TWO_SIDE, lmodel_twoside);
  glLightModelfv(GL_LIGHT_MODEL_AMBIENT, lmodel_ambient);
  glEnable(GL_LIGHTING);

  glMaterialfv(GL_FRONT, GL_AMBIENT, bevel_mat_ambient);
  glMaterialfv(GL_FRONT, GL_SHININESS, bevel_mat_shininess);
  glMaterialfv(GL_FRONT, GL_SPECULAR, bevel_mat_specular);
  glMaterialfv(GL_FRONT, GL_DIFFUSE, bevel_mat_diffuse);

  glColorMaterial(GL_FRONT_AND_BACK, GL_DIFFUSE);
  glEnable(GL_COLOR_MATERIAL);
  glShadeModel(GL_SMOOTH);
 
  glMatrixMode(GL_PROJECTION);
  gluPerspective(45, 1.33, 0.1, 100.0);
  glMatrixMode(GL_MODELVIEW);
}

void CALLBACK Reshape(int width, int height)
{
  glViewport(0, 0, width, height);
}

void main(int argc, char **argv)
{
  auxInitPosition(0, 0, 400, 300);
  auxInitDisplayMode(AUX_RGB|AUX_DOUBLE);
  auxInitWindow("Olympic");
  Init();
  auxReshapeFunc(Reshape);
  auxIdleFunc(Idle);
  auxMainLoop(DrawScene);
}