Today I tired to experiment with glMultMatrix for rendering a simple cube.Initially My I focuseed by viewing position using gluLookAt.Later I changed it using glMultMatrix by specify 4x4 matrix. Now cube is partially clipped. Why is it so. I have not changed projection values. Below is code.
#include <GL/glut.h>
#include <GL/gl.h>
#include <stdlib.h>
#include <math.h>
#define PI 22/7
float theta=90*PI/180;
GLfloat T[16]={1,0,0,0,0,1,0,0,0,0,-5.0,0,0,0,0,1};
void init(void)
{
glClearColor (0.0, 0.0, 0.0, 0.0);
glShadeModel (GL_FLAT);
}
void display(void)
{
glClear (GL_COLOR_BUFFER_BIT);
glColor3f (1.0, 1.0, 1.0);
glLoadIdentity (); /* clear the matrix /
/ viewing transformation /
//gluLookAt (0.0, 0.0, 5.0, 0.0, 0.0, 0.0, 0.0, 1.0, 0.0);
glMultMatrixf(T);
//glScalef (1.0, 2.0, 1.0); / modeling transformation */
glutWireCube (1.0);
glFlush ();
}
void reshape (int w, int h)
{
glViewport (0, 0, (GLsizei) w, (GLsizei) h);
glMatrixMode (GL_PROJECTION);
glLoadIdentity ();
glFrustum (-1.0, 1.0, -1.0, 1.0, 1.5, 20.0);
glMatrixMode (GL_MODELVIEW);
}
void keyboard(unsigned char key, int x, int y)
{
switch (key) {
case 27:
exit(0);
break;
}
}
int main(int argc, char** argv)
{
glutInit(&argc, argv);
glutInitDisplayMode (GLUT_SINGLE | GLUT_RGB);
glutInitWindowSize (500, 500);
glutInitWindowPosition (100, 100);
glutCreateWindow (argv[0]);
init ();
glutDisplayFunc(display);
glutReshapeFunc(reshape);
glutKeyboardFunc(keyboard);
glutMainLoop();
return 0;
}