There are some error messages when I run the fogindex.c.
First, I input g++ -Wall -o fogindex fogindex.c -lglut[/b] in terminal on ubuntu 10.04. That’s ok.
Second, there are some error messages after I input ./fogindex:
X Error of failed request: BadMatch (invalid parameter attributes)
Major opcode of failed request: 128 (GLX)
Minor opcode of failed request: 26 (X_GLXMakeContextCurrent)
Serial number of failed request: 48
Current serial number in output stream: 48[/b]
So who can help me solve the problem. By the way, the codes are extracted from OpenGL Programming Guide 6th, whose authors are Dave Shreiner, Mason Woo, Jackie Neider, Tom Davis.
The Codes are listed:
/*
- fogindex.c
- This program draws 5 wireframe spheres, each at
- a different z distance from the eye, in linear fog.
*/
#include <GL/glut.h>
#include <math.h>
#include <stdlib.h>
#include <stdio.h>
/* Initialize color map and fog. Set screen clear color
- to end of color ramp.
*/
#define NUMCOLORS 32
#define RAMPSTART 16
static void init(void)
{
int i;
glEnable(GL_DEPTH_TEST);
for (i = 0; i < NUMCOLORS; i++) {
GLfloat shade;
shade = (GLfloat) (NUMCOLORS-i)/(GLfloat) NUMCOLORS;
glutSetColor (RAMPSTART + i, shade, shade, shade);
}
glEnable(GL_FOG);
glFogi (GL_FOG_MODE, GL_LINEAR);
glFogi (GL_FOG_INDEX, NUMCOLORS);
glFogf (GL_FOG_START, 1.0);
glFogf (GL_FOG_END, 6.0);
glHint (GL_FOG_HINT, GL_NICEST);
glClearIndex((GLfloat) (NUMCOLORS+RAMPSTART-1));
}
static void renderSphere (GLfloat x, GLfloat y, GLfloat z)
{
glPushMatrix();
glTranslatef (x, y, z);
glutWireSphere(0.4, 16, 16);
glPopMatrix();
}
/* display() draws 5 spheres at different z positions.
*/
void display(void)
{
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glIndexi (RAMPSTART);
renderSphere (-2., -0.5, -1.0);
renderSphere (-1., -0.5, -2.0);
renderSphere (0., -0.5, -3.0);
renderSphere (1., -0.5, -4.0);
renderSphere (2., -0.5, -5.0);
glFlush();
}
void reshape(int w, int h)
{
glViewport(0, 0, w, h);
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
if (w <= h)
glOrtho (-2.5, 2.5, -2.5*(GLfloat)h/(GLfloat)w,
2.5*(GLfloat)h/(GLfloat)w, -10.0, 10.0);
else
glOrtho (-2.5*(GLfloat)w/(GLfloat)h,
2.5*(GLfloat)w/(GLfloat)h, -2.5, 2.5, -10.0, 10.0);
glMatrixMode(GL_MODELVIEW);
glLoadIdentity ();
}
void keyboard(unsigned char key, int x, int y)
{
switch (key) {
case 27:
exit(0);
}
}
/* Main Loop
- Open window with initial window size, title bar,
- color index mode, depth buffer, and handle input events.
/
int main(int argc, char* argv)
{
glutInit(&argc, argv);
glutInitDisplayMode (GLUT_SINGLE | GLUT_INDEX | GLUT_DEPTH);
glutInitWindowSize(500, 500);
glutCreateWindow(argv[0]);
init();
glutReshapeFunc (reshape);
glutKeyboardFunc (keyboard);
glutDisplayFunc (display);
glutMainLoop();
return 0;
}
