gluPerspective problem

Ehsan_Nekooee · August 14, 2009, 10:50am

gluPerspective doesn’t work in this code, Just shows a white Blank screen, If I change it to glOrtho and it will work.
Any suggestions why perspective doesn’t work?

here is the code:


#include "stdafx.h"
#include "glut.h"
#include "math.h"
#include <stdio.h>
const double Xmin = 0.0, Xmax = 800.0;
const double Ymin = 0.0, Ymax = 600.0;

/*---------------- Resize Function ---------------*/

void resize(int w, int h)
{

	double scale, center;
	double windowXmin, windowXmax, windowYmin, windowYmax;

	glViewport( 0, 0, w, h );	// View port uses whole window

	w = (w==0) ? 1 : w;
	h = (h==0) ? 1 : h;
	if ( (Xmax-Xmin)/w < (Ymax-Ymin)/h ) {
		scale = ((Ymax-Ymin)/h)/((Xmax-Xmin)/w);
		center = (Xmax+Xmin)/2;
		windowXmin = center - (center-Xmin)*scale;
		windowXmax = center + (Xmax-center)*scale;
		windowYmin = Ymin;
		windowYmax = Ymax;
	}
	else {
		scale = ((Xmax-Xmin)/w)/((Ymax-Ymin)/h);
		center = (Ymax+Ymin)/2;
		windowYmin = center - (center-Ymin)*scale;
		windowYmax = center + (Ymax-center)*scale;
		windowXmin = Xmin;
		windowXmax = Xmax;
	}
	
	glMatrixMode( GL_PROJECTION );
	glLoadIdentity();
	//glOrtho( windowXmin, windowXmax, windowYmin, windowYmax, -1200, 1200 );
	gluPerspective(60.0f,(float)w/(float)h,0,600);
	glMatrixMode(GL_MODELVIEW);
	glLoadIdentity();
}

/*--------------------- show function -------------------*/


void show (){

		float v[3][3];
		glMatrixMode(GL_MODELVIEW);
		glLoadIdentity();
		glShadeModel(GL_SMOOTH);
		glEnable(GL_DEPTH_TEST);
		glClear (GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
		glClearColor(1,1,1,1);
		glHint(GL_PERSPECTIVE_CORRECTION_HINT,GL_NICEST);
		

		//glDepthFunc(GL_ALWAYS);
	glColor4f(1,0,1,0.5);

		glBegin(GL_QUADS);
			
		// Front
						
			glVertex3f(200,500,0);
			glColor4f(0,0,1,1);
			glVertex3f(200,200,0);
			glColor4f(1,1,0,1);
			glVertex3f(500,200,0);
			glColor4f(0,1,1,1);
			glVertex3f(500,500,0);
		glEnd();
		
	glBegin(GL_QUADS);
		
		glColor4f(0,1,0,1);
		// Top
			glVertex3f(200,500,300);
			glColor4f(0.4,0.7,0.3,1);
			glVertex3f(200,500,0);
			glColor4f(1,0.6,0,1);
			glVertex3f(500,500,0);
			glColor4f(0.8,0.1,0.4,1);
			glVertex3f(500,500,300);
	glEnd();		
		glBegin(GL_QUADS);

	// Right
		glColor4f(0,0,1,1);
			glVertex3f(500,500,0);
			glColor4f(0.6,0.7,0.6,1);
			glVertex3f(500,200,0);
			glColor4f(0.2,0.5,0.1,1);
			glVertex3f(500,200,300);
			glColor4f(0,0.5,0.7,1);
			glVertex3f(500,500,300);
		glEnd();
//		glDepthFunc(GL_LEQUAL);
			glBegin(GL_QUADS);
			// Left
			glColor4f(0.4,1,1,1);
			glVertex3f(200,500,300);
			glColor4f(0.4,1,0.7,1);		
			glVertex3f(200,200,300);
			glColor4f(0.2,1,0.8,1);
			glVertex3f(200,200,0);
			glColor4f(1,0,1,1);
			glVertex3f(200,500,0);
			glEnd();
//			glDepthFunc(GL_LEQUAL);
			glBegin(GL_QUADS);

			// Back
			glColor4f(1,0,0,1);
			glVertex3f(200,500,300);
		//	glColor4f(0.7,0,1,1);
			glVertex3f(200,200,300);
		//	glColor4f(0.4,1,1,1);
			glVertex3f(500,200,300);
		//	glColor4f(1,0.2,1,1);
			glVertex3f(500,500,300);
			glEnd();
//glDepthFunc(GL_LEQUAL);
			glBegin(GL_QUADS);
			// Bottem
			glColor4f(0.5,0,0.5,1);
			glVertex3f(200,200,0);
			glColor4f(1,1,0,1);
			glVertex3f(200,200,300);
			glColor4f(0,1,0,1);
			glVertex3f(500,200,300);
			glColor4f(0,1,0.7,1);
			glVertex3f(500,200,0);
			glEnd();
			glPopMatrix();
		glutSwapBuffers();		
			glFlush();
}
 

int main(int argc, char *argv[])
{
	glutInit(&argc,argv);
	glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
	glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE |GLUT_DEPTH );
	glutInitWindowPosition( 0, 0 );
	glutInitWindowSize( 1024, 768 );
	glutCreateWindow("My Window");
	glutReshapeFunc( resize );
	glutDisplayFunc(show);
	glutTimerFunc(0,Timer,0);
	glutMainLoop();
	return 0;
}

DarkShadow44 · August 14, 2009, 10:57am

Try to use

gluPerspective(60.0f,(float)w/(float)h,0.1,600);

instead of

gluPerspective(60.0f,(float)w/(float)h,0,600);

Ehsan_Nekooee · August 14, 2009, 11:04am

Well, Thanx for your concern.
I changed it but still nothing happening. still nothing shown on the screen.

I am really confused what’s happening to my code?

DarkShadow44 · August 14, 2009, 11:30am

Your model is ver, very, very big ; use this code:

 glMatrixMode(GL_MODELVIEW);
		glLoadIdentity();
		glShadeModel(GL_SMOOTH);
		glEnable(GL_DEPTH_TEST);
		glClear (GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
		//!!glClearColor(1,1,1,1);
		glHint(GL_PERSPECTIVE_CORRECTION_HINT,GL_NICEST);
    glTranslatef( -5.0f, -5.0f, -50.0f );
   // glRotatef( fXrot, 1.0f, 0.0f, 0.0f );
    //glRotatef( fYrot, 0.0f, 1.0f, 0.0f );
   // glRotatef( fZrot, 0.0f, 0.0f, 1.0f );

	

    //glBindTexture( GL_TEXTURE_2D, g_textureID );
	

	glColor4f(1,0,1,0.5);

		glBegin(GL_QUADS);
			
		// Front
						
			glVertex3f(2,5,0);
			glColor4f(0,0,1,1);
			glVertex3f(2,2,0);
			glColor4f(1,1,0,1);
			glVertex3f(5,2,0);
			glColor4f(0,1,1,1);
			glVertex3f(5,5,0);
		glEnd();
		
	glBegin(GL_QUADS);
		
		glColor4f(0,1,0,1);
		// Top
			glVertex3f(2,5,3);
			glColor4f(0.4,0.7,0.3,1);
			glVertex3f(2,5,0);
			glColor4f(1,0.6,0,1);
			glVertex3f(5,5,0);
			glColor4f(0.8,0.1,0.4,1);
			glVertex3f(5,5,3);
	glEnd();		
		glBegin(GL_QUADS);

	// Right
		glColor4f(0,0,1,1);
			glVertex3f(5,5,0);
			glColor4f(0.6,0.7,0.6,1);
			glVertex3f(5,2,0);
			glColor4f(0.2,0.5,0.1,1);
			glVertex3f(5,2,3);
			glColor4f(0,0.5,0.7,1);
			glVertex3f(5,5,3);
		glEnd();
//		glDepthFunc(GL_LEQUAL);
			glBegin(GL_QUADS);
			// Left
			glColor4f(0.4,1,1,1);
			glVertex3f(2,5,3);
			glColor4f(0.4,1,0.7,1);		
			glVertex3f(2,2,3);
			glColor4f(0.2,1,0.8,1);
			glVertex3f(2,2,0);
			glColor4f(1,0,1,1);
			glVertex3f(2,5,0);
			glEnd();
//			glDepthFunc(GL_LEQUAL);
			glBegin(GL_QUADS);

			// Back
			glColor4f(1,0,0,1);
			glVertex3f(2,5,3);
		//	glColor4f(0.7,0,1,1);
			glVertex3f(2,2,3);
		//	glColor4f(0.4,1,1,1);
			glVertex3f(5,2,3);
		//	glColor4f(1,0.2,1,1);
			glVertex3f(5,5,3);
			glEnd();
//glDepthFunc(GL_LEQUAL);
			glBegin(GL_QUADS);
			// Bottem
			glColor4f(0.5,0,0.5,1);
			glVertex3f(2,2,0);
			glColor4f(1,1,0,1);
			glVertex3f(2,2,3);
			glColor4f(0,1,0,1);
			glVertex3f(5,2,3);
			glColor4f(0,1,0.7,1);
			glVertex3f(5,2,0);
			glEnd();

And my other code too, I think it won’t work with yours

With rotation, you can see your model ; how did you create that ? Looks nice ^^

Ehsan_Nekooee · August 14, 2009, 12:32pm

thanx DarkShadow44

I don’t know how could I use those big scales !

It might sound stupid but I placed a big Dictionary book in front of myself which has about 1000 pages! I looked at it and assumed what might be the edges! Of course these numbers are not the real dictionary dimensions but Really helped me

DarkShadow44 · August 14, 2009, 12:39pm

You could create your models with blender.

Then you can load it in your programm. ^^

I’ve written a little engine (+exporter), which loads models,textures and animations

Ehsan_Nekooee · August 14, 2009, 12:50pm

Can you tell me in a few words what is exactly an engine and how could I build my own?

DarkShadow44 · August 14, 2009, 1:02pm

An engine is a part of code which you can include and that should make development much easier.
It helps you for example with loading models, animating, collisions…

But my one can only load models ^^

To build one, you must collect/write a texture loader, model loader, etc.