第7章代码-真实感图形技术

#include <GL/glut.h>
#include <stdlib.h>
#include <stdio.h>
#define stripeImageWidth 32
GLubyte stripeImage[4*stripeImageWidth];
void makeStripeImage(void) 		//生成纹理
{  int j;    
   for (j=0; j<stripeImageWidth; j++) 
   {
   stripeImage[4*j+0] = (GLubyte) ((j<=4)?255:0); 
      stripeImage[4*j+1] = (GLubyte) ((j>4)?255:0);  
      stripeImage[4*j+2] = (GLubyte) 0;
      stripeImage[4*j+3] = (GLubyte) 255;
   }
}
// 平面纹理坐标生成
static GLfloat xequalzero[] = {1.0, 1.0, 1.0, 1.0};
static GLfloat slanted[] = {1.0, 1.0, 1.0, 0.0};
static GLfloat *currentCoeff;
static GLenum currentPlane;
static GLint currentGenMode;
static float roangles;
void init(void)
{ glClearColor (1.0, 1.0, 1.0, 1.0);
  glEnable(GL_DEPTH_TEST);
  glShadeModel(GL_SMOOTH);
  makeStripeImage();
  glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
  glTexParameteri(GL_TEXTURE_1D, GL_TEXTURE_WRAP_S, GL_REPEAT);
  glTexParameteri(GL_TEXTURE_1D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
  glTexParameteri(GL_TEXTURE_1D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
  glTexImage1D(GL_TEXTURE_1D, 0, 4, stripeImageWidth, 0,
                GL_RGBA, GL_UNSIGNED_BYTE, stripeImage);
  glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);
  currentCoeff = xequalzero;
  currentGenMode = GL_OBJECT_LINEAR;
  currentPlane = GL_OBJECT_PLANE;
  glTexGeni(GL_S, GL_TEXTURE_GEN_MODE, currentGenMode);
  glTexGenfv(GL_S, currentPlane, currentCoeff);
  glEnable(GL_TEXTURE_GEN_S);
  glEnable(GL_TEXTURE_1D);
  glEnable(GL_LIGHTING);
  glEnable(GL_LIGHT0);
  glEnable(GL_AUTO_NORMAL);
  glEnable(GL_NORMALIZE);
  glFrontFace(GL_CW);
  glMaterialf (GL_FRONT, GL_SHININESS, 64.0);
  roangles=45.0f;
}
void display(void)
{  glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
   glPushMatrix ();
   glRotatef(roangles,0.0,0.0,1.0);
   glutSolidSphere(2.0,32,32 );
   glPopMatrix ();
   glFlush();
}
void reshape(int w, int h)
{  glViewport(0, 0, (GLsizei) w, (GLsizei) h);
   glMatrixMode(GL_PROJECTION);
   glLoadIdentity();
   if (w <= h)
      glOrtho (-3.5, 3.5, -3.5*(GLfloat)h/(GLfloat)w, 
               3.5*(GLfloat)h/(GLfloat)w, -3.5, 3.5);
   else
      glOrtho (-3.5*(GLfloat)w/(GLfloat)h, 
               3.5*(GLfloat)w/(GLfloat)h, -3.5, 3.5, -3.5, 3.5);
   glMatrixMode(GL_MODELVIEW);
   glLoadIdentity();
}
void idle()
{   roangles += 0.05f;
    glutPostRedisplay();
}
int main(int argc, char** argv)
{
   glutInit(&argc, argv);
   glutInitDisplayMode (GLUT_SINGLE | GLUT_RGB | GLUT_DEPTH);
   glutInitWindowSize(256, 256);
   glutInitWindowPosition(100, 100);
   glutCreateWindow (argv[0]);
   glutIdleFunc(idle);
   init ();
   glutDisplayFunc(display);
   glutReshapeFunc(reshape);
   glutMainLoop();
   return 0;
}