freeglut

?

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84

#include <iostream> #include <gl/glut.h>   using namespace std;   struct Point {     int x;     int y; };   //   #define VERTEX_COUNT 5   Point points[VERTEX_COUNT] = {         103, 273,         516, 273,         184, 32,         308, 452,         439, 32 };   //   void draw_dda(Point p1, Point p2) {     GLfloat dx = p2.x - p1.x;     GLfloat dy = p2.y - p1.y;       GLfloat x1 = p1.x;     GLfloat y1 = p1.y;       GLfloat step = 0;       if(abs(dx) > abs(dy)) {         step = abs(dx);     } else {         step = abs(dy);     }       GLfloat xInc = dx/step;     GLfloat yInc = dy/step;       for(float i = 1; i <= step; i++) {         glVertex2i(x1, y1);         x1 += xInc;         y1 += yInc;     } }   void init() {     glClearColor(1.0, 1.0, 1.0, 0.0);     glColor3f(0.0f, 0.0f, 0.0f);     gluOrtho2D(0.0, 640.0, 0.0, 480.0);     glMatrixMode(GL_PROJECTION);     glLoadIdentity();     glPointSize(1.0f); }   void display() {     glClear(GL_COLOR_BUFFER_BIT);     glBegin(GL_POINTS);     Point stPoint = points[0];       for(int i = 1; i < VERTEX_COUNT; i++) {         draw_dda(stPoint, points[i]);         stPoint = points[i];     }     draw_dda(stPoint, points[0]);       glEnd();     glFlush(); }   int main(int argc, char** argv) {     glutInit(&argc, argv);     glutInitWindowPosition(400, 200);     glutInitWindowSize(640, 480);     glutInitDisplayMode(GLUT_SINGLE|GLUT_RGB);     glutCreateWindow("OpenGL");     init();     glutDisplayFunc(display);     glutMainLoop();     return 0; }