Grafika pelda program

#include <math.h>
#include <stdlib.h>

#if defined(__APPLE__)
  #include <OpenGL/gl.h>
  #include <OpenGL/glu.h>
  #include <GLUT/glut.h>
#else
  #if defined(WIN32) || defined(_WIN32) || defined(__WIN32__)
    #include <windows.h>
  #endif
  #include <GL/gl.h>
  #include <GL/glu.h>
  #include <GL/glut.h>
#endif

void onInitialization() {
}

#define CIRCLE_RESOLUTION 32

void onDisplay() {
  glClear(GL_COLOR_BUFFER_BIT);

  // A piros kor, a kepernyo bal oldalan
  glBegin(GL_TRIANGLE_FAN); {
    float radius = 0.25f, center_x = -0.5f, center_y = 0.4f;

    glColor3f(1.0f, 0.0f, 0.0f);
    glVertex2f(center_x, center_y);

    for(int i = 0; i <= CIRCLE_RESOLUTION; i++) {
      float angle = float(i) / CIRCLE_RESOLUTION * 2.0f * M_PI;
      // Itt a kor paramtetrikus alakjat hasznaljuk: x = x0 + r*cos(t), y = y0 + r * sin(t)
      glVertex2f(center_x + radius*cos(angle), center_y + radius*sin(angle));
    }
  } glEnd();

  // Szinatmenetes kor, a kepernyo jobb oldalan
  glBegin(GL_TRIANGLE_FAN); {
    float radius = 0.25f, center_x = 0.5f, center_y = 0.4f;

    glColor3f(0.0f, 1.0f, 1.0f);
    glVertex2f(center_x, center_y);

    for(int i = 0; i <= CIRCLE_RESOLUTION; i++) {
      float angle = float(i) / CIRCLE_RESOLUTION * 2.0f * M_PI;
      glColor3f(0.0f, 0.5f + 0.5f*cos(angle), 0.5f + 0.5f*sin(angle));
      glVertex2f(center_x + radius*cos(angle), center_y + radius*sin(angle));
    }
  } glEnd();

  // Felkoriv
  glBegin(GL_LINE_STRIP); {
    float radius = 0.75f, center_x = 0.0f, center_y = 0.0f;

    glColor3f(1.0f, 1.0f, 1.0f);

    for(int i = CIRCLE_RESOLUTION/2; i <= CIRCLE_RESOLUTION; i++) {
      float angle = float(i) / CIRCLE_RESOLUTION * 2.0f * M_PI;
      glVertex2f(center_x + radius*cos(angle), center_y + radius*sin(angle));
    }
  } glEnd();

  glutSwapBuffers();
}

void onMouse(int, int, int, int) {
}

void onMouseMotion(int, int) {
}

void onKeyboard(unsigned char, int, int) {
}

void onKeyboardUp(unsigned char, int, int) {
}

void onIdle() {
}

int main(int argc, char **argv) {
  glutInit(&argc, argv);
  glutInitWindowSize(600, 600);
  glutInitWindowPosition(100, 100);
  glutInitDisplayMode(GLUT_RGBA | GLUT_DOUBLE | GLUT_DEPTH);

  glutCreateWindow("Grafika pelda program");

  glMatrixMode(GL_MODELVIEW);
  glLoadIdentity();
  glMatrixMode(GL_PROJECTION);
  glLoadIdentity();

  onInitialization();

  glutDisplayFunc(onDisplay);
  glutMouseFunc(onMouse);
  glutIdleFunc(onIdle);
  glutKeyboardFunc(onKeyboard);
  glutKeyboardUpFunc(onKeyboardUp);
  glutMotionFunc(onMouseMotion);

  glutMainLoop();

  return 0;
}