8.6.4编程实例－纹理映射
#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;
}