earthtex.c

opengl source code download

#include "windows.h"
#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#include <math.h>
#include <float.h>
#include <GL/gl.h>
#include <GL/glu.h>
#include <GL/glaux.h>

#define PI 3.1415926

GLfloat step = 0.0, viewdis = 20., viewrotx = 0., viewroty = 0.;

typedef struct {float x,y,z;} Ppoint3;

Ppoint3 sphere[36][36];

void myinit(void);
void CALLBACK myReshape(GLsizei w, GLsizei h);
void CALLBACK display(void);
void makeStripeImage(void);

AUX_RGBImageRec *image;
GLubyte *stripeImage;

void myinit(void)
{
  	GLfloat mat_ambient[]={0.1,0.1,0.1,1.0};
  	GLfloat mat_diffuse[]={0.7,0.,0.,1.0};
    GLfloat mat_specular[] = { .5, 0.5, 0.5, 1.0 };
    GLfloat mat_shininess[] = { 50.0 };
  	GLfloat light_ambient[]={0.3,0.3,0.3,1.0};
    GLfloat light_position[] = { 1.0, 1.0, 1.0, 0.0 };
	
	glMaterialfv(GL_FRONT, GL_AMBIENT, mat_ambient);
    glMaterialfv(GL_FRONT, GL_DIFFUSE, mat_diffuse);
    glMaterialfv(GL_FRONT, GL_SPECULAR, mat_specular);
    glMaterialfv(GL_FRONT, GL_SHININESS, mat_shininess);
    glLightfv(GL_LIGHT0, GL_POSITION, light_position);
    glLightfv(GL_LIGHT0, GL_AMBIENT, light_ambient);

    glEnable(GL_LIGHTING);
    glEnable(GL_LIGHT0);	
    glEnable(GL_DEPTH_TEST);
    glEnable(GL_TEXTURE_2D);

	initsphere(1.0,18,36,sphere);

    glClearColor (0.0, 0.0, 0.0, 0.0);

    makeStripeImage();
    glPixelStorei(GL_UNPACK_ALIGNMENT, 1);

    glTexImage2D(GL_TEXTURE_2D, 0, 3, image->sizeX,image->sizeY, 0,
         GL_RGB, GL_UNSIGNED_BYTE, stripeImage);
//    glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
//    glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP);
    glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
    glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
//    glTexEnvi(GL_TEXTURE_ENV,GL_TEXTURE_ENV_MODE,GL_BLEND);
//    glTexEnvi(GL_TEXTURE_ENV,GL_TEXTURE_ENV_MODE,GL_DECAL);
   glTexEnvi(GL_TEXTURE_ENV,GL_TEXTURE_ENV_MODE,GL_MODULATE);
	
}

void CALLBACK display(void)
{
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

    glPushMatrix();
       glRotatef(step,0.0,1.0,0.0);
       fillsphere(18,36,sphere);
    glPopMatrix();

	step+=0.1;

	glFlush();
	auxSwapBuffers();
}


void CALLBACK myReshape(GLsizei w, GLsizei h)
{
    glViewport(0, 0, w, h);
    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    if (w <= h) 
    glOrtho (-1.5, 1.5, -1.5*(GLfloat)h/(GLfloat)w, 
        1.5*(GLfloat)h/(GLfloat)w, -10.0, 100.0);
    else 
    glOrtho (-1.5*(GLfloat)w/(GLfloat)h, 
        1.5*(GLfloat)w/(GLfloat)h, -1.5, 1.5, -10.0, 100.0);
    glMatrixMode(GL_MODELVIEW);
    glLoadIdentity();
	gluLookAt(12,10,12,0,0,0,0,1,0);
}

initsphere(rad,nlat,nlong,point)
float rad;
int nlat,nlong;
Ppoint3 point[][37];
{
   int i,j,maxlat=36,maxlong=36;
   double pi=3.1415926,inclat,jj,dval,magnitude;

   if(nlat>maxlat) nlat=maxlat;
   if(nlong>maxlong) nlong=maxlong;
   
   inclat=pi/2.;
   for(i=0;i<nlat;i++)
   { /* go around cross section */
	 magnitude=cos(inclat)*rad;
	 dval=sin(inclat)*rad;

	 for(j=0;j<nlong+1;j++) 
	    point[i][j].y=(float) dval;
	 for(j=0;j<nlong+1;j++)
	    { /* go around top view */
	      jj=(double)j;
	      dval=cos(2.*pi*jj/nlong)*magnitude;
	      point[i][j].x=(float)dval;
	      dval=sin(2.*pi*jj/nlong)*magnitude;
	      point[i][j].z=(float)dval;
	     }
	     inclat=inclat-(pi/(float)(nlat-1));
	}
     return(0);
}

fillsphere(nlat,nlong,point)
int nlat,nlong;
float point[][37][3];
{
   int i,j;
   float tx,ty;

   ty=1.0/(float)(nlat-1);
   tx=1.0/(float)nlong;
   for(i=0;i<nlat;i++) {
      glBegin(GL_QUAD_STRIP);
      for(j=0;j<nlong+1;j++)
      {  
		       glTexCoord2f((float)j*tx,(float)(i+1)*ty);
	           glNormal3fv(point[i+1][j]); 
			   glVertex3fv(point[i+1][j]);
		       glTexCoord2f((float)j*tx,(float)i*ty);
	           glNormal3fv(point[i][j]); 
			   glVertex3fv(point[i][j]);
       }   //    end j
	   glEnd();
    }       //   end i
    return(0); 
}

void makeStripeImage(void)
{

    image=auxDIBImageLoad("earth.bmp");
	if(image==NULL) exit(-1);
	glPixelStorei(GL_UNPACK_ALIGNMENT,1);

    stripeImage=(GLubyte *)malloc(3*image->sizeX*image->sizeY*sizeof(GLubyte));

	gluScaleImage(GL_RGB,image->sizeX,image->sizeY,GL_UNSIGNED_BYTE,
		          image->data,image->sizeX,image->sizeY,
                  GL_UNSIGNED_BYTE,stripeImage);
}

void main(void)
{
    auxInitDisplayMode (AUX_DOUBLE | AUX_RGBA);
    auxInitPosition (100,100, 800, 600);
    auxInitWindow ("地球");
    myinit();
    auxReshapeFunc (myReshape);
    auxIdleFunc (display);
    auxMainLoop(display);
}