Perspective problem

[swethasharma]

Hello,

I have written code to draw a sphere. I have referred the code for drawing a sphere from swiftless tutorial.I am able to view the sphere only when i do orthographic projection.I am not able to view the sphere under perspective projection.

#define GLEW_STATIC
#include <stdio.h>
#include <stdlib.h>
#include <gl/glew.h>
#include <glfw.h>
#include <math.h>
 
 
#define space 10
#define  vertexcount (90/space)*(360/space)*4
 
 
 
const double PI=3.1415926535897;
 
 struct Vertices
{
	double x;
	double y;
	double z;
} vertex [vertexcount];
 
void init(void)
{
	int glewinitialize;
	//Vertices vertex[vertexcount];
	//float aspect_ratio;
	glClearColor(0.0,0.0,0.0,0.0);
	glClearDepth(1.0);
	glShadeModel(GL_FLAT);
    glewinitialize=glewInit();
	if(glewinitialize==GLEW_OK)
	{
		printf("GLEW is available\n");
	}
 
}
 
void GLFWCALL reshape(int width,int height)
{
 
	glViewport(0,0,500,500);
   glMatrixMode(GL_PROJECTION);
 
   glLoadIdentity();
 // glOrtho(-10.0,(GLdouble)10.0,-10.0,(GLdouble)10.0,-10.0,200.0);
 
  gluPerspective(60.0,width/height,0.1,100.0);
  glMatrixMode(GL_MODELVIEW);
 
 
}
 
 
void createsphere(int R,int H,int K,int Z)
{
	int n;
	int a;
	int b;
	int debug=0;
 
	double A;
	double B;
 
 
	n=0;
	for(b=0;b<=90-space;b+=space)
	{
		for(a=0;a<=360-space;a+=space)
		{
 
			vertex[n].x=R*(sin((a*PI)/180))*(sin((b*PI)/180))-H;
			vertex[n].y=R*(cos((a*PI)/180))*(sin((b*PI)/180))+K;
			vertex[n].z=R*(cos((b*PI)/180))-Z;
			n++;
 
			vertex[n].x=R*(sin((a*PI)/180))*(sin(((b+space)*PI)/180))-H;
			vertex[n].y=R*(cos((a*PI)/180))*(sin(((b+space)*PI)/180))+K;
			vertex[n].z=R*(cos(((b+space)*PI)/180))-Z;
 
			n++;
 
			vertex[n].x=R*(sin(((a+space)*PI)/180))*(sin((b*PI)/180))-H;
			vertex[n].y=R*(cos(((a+space)*PI)/180))*(sin((b*PI)/180))+K;
			vertex[n].z=R*(cos((b*PI)/180))-Z;
			n++;
 
			vertex[n].x=R*(sin(((a+space)*PI)/180))*(sin(((b+space)*PI)/180))-H;
			vertex[n].y=R*(cos(((a+space)*PI)/180))*(sin(((b+space)*PI)/180))+K;
			vertex[n].z=R*(cos(((b+space)*PI)/180))-Z;
			n++;
		}
	}
}
 
void displaysphere(double R)
{
	int b;
	glLoadIdentity();
	gluLookAt(0.0,0.0,1.0,0.0,0.0,0.0,0.0,1.0,0.0);
	glScalef(0.0125*R,0.0125*R,0.0125*R);
//	glRotatef(90,1.0,0.0,0.0);
	glBegin(GL_TRIANGLE_STRIP);
	for( b=0;b<=vertexcount;b++)
	{
		glVertex3f(vertex[B].x,vertex[B].y,-vertex[B].z);
	}
 
	for( b=0;b<=vertexcount;b++)
	{
		glVertex3f(vertex[B].x,vertex[B].y,vertex[B].z);
	}
    glEnd();
}
void display(void)
{
	GLfloat mat[16];
    glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT);
	glColor3f(1.0,0.5,0.0);
	glLoadIdentity();
 
 
 
	glEnable(GL_DEPTH_TEST);
	glDepthFunc(GL_LEQUAL);
	glCullFace(GL_BACK);
	glFrontFace(GL_CCW);
	glEnable(GL_CULL_FACE);
 
    createsphere(70,0,0,0);
	displaysphere(5);
 
    glfwSwapBuffers();
}
int main(int argc,char** argv)
{
 
	int wndstate,wndopenstate;
 
	wndstate=glfwInit();
 
	if(wndstate==1)
	{
		wndopenstate=glfwOpenWindow(640,480,0,0,0,0,4,0,GLFW_WINDOW);
 
		if(wndopenstate==0)
		{
			glfwTerminate();
		}
		else
		{
			glfwSetWindowTitle("Hello Opengl");
			glfwSetWindowPos(30,30);
			init();
			glfwSetWindowSizeCallback(reshape);
 
			while(1)
			{
				display();
				 if(glfwGetKey(GLFW_KEY_ESC))
	             {
		             glfwTerminate();
 
	             }
 
			}
		}
	}
 
	glfwTerminate();
	return 0;
 
  }

Where is the mistake?
-swetha

[BionicBytes]

Try drawing the sphere into the projected screen a bit more so it is not clipped by the camera fustrum.

After
gluLookAt(0.0,0.0,1.0,0.0,0.0,0.0,0.0,1.0,0.0);

add
gltranslatef (0,0,-10.0);

[swethasharma]

Hi BionicBytes,

Got it . Thanks a lot.
-swetha