Hi,
I have a little problem with using these two function, if anyone could help 
What I want to achieve ?
- draw a few points at the window
- draw at the bottom small view of this drawed points
First I draw the points, then after glScissor() and glViewPort(), I’m trying to make a orthographic viewing, but it only shows the black screen.
#include <GL/glut.h>
#include <stdio.h>
#include <stdlib.h>
void display()
{
int i;
glEnable(GL_SCISSOR_TEST);
glMatrixMode(GL_MODELVIEW);
glClearColor(0.0f,0.0f,0.0f,0.0f);
glClear(GL_COLOR_BUFFER_BIT);
glColor3f(0.0f,1.0f,0.0f);
//draw few points
glPointSize(15);
glBegin(GL_LINE_STRIP);
for(i=0;i<100;i++)
glVertex2f(rand()%800,rand()%500);
glEnd();
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
glViewport (0, 100, (GLsizei) 800, (GLsizei) 500);
glScissor (0, 100, (GLsizei) 800, (GLsizei) 500);
gluOrtho2D(0, 800, 0, 500 );
glLoadIdentity();
glViewport(0,0,800,100);
glScissor(0,0,800,100);
gluOrtho2D(0, 800, 0, 500 );
glFinish();
}
int main(int argc,char**argv)
{
srand(time(NULL));
glutInit(&argc,argv);
glutInitDisplayMode(GLUT_RGBA | GLUT_SINGLE);
glutInitWindowSize(800,600);
glutCreateWindow("POINTS");
glutDisplayFunc(display);
glutMainLoop();
}
plz help me