学步园

#include <iostream>

using namespace std;
#include <GL/glut.h>
#include <stdlib.h>
#include <stdio.h>


#define checkImageWidth 64  //图片宽度
#define checkImageHeight 64 //图片高度

static GLubyte checkImage[checkImageWidth][checkImageHeight][4];//定义图片，RBGA


//生成黑白相间的图片
void makeCheckImage(void)
{
    int i, j, c;

    for (i = 0; i < checkImageHeight; i++) {
       for (j = 0; j < checkImageWidth; j++) {
          c = ((((i&0x8)==0)^((j&0x8))==0))*255;
          checkImage[i][j][0] = (GLubyte) c;
          checkImage[i][j][1] = (GLubyte) c;
          checkImage[i][j][2] = (GLubyte) c;
          checkImage[i][j][3] = (GLubyte) 255;
       }
    }
}


void init(void)
{
    //清空用黑色
    glClearColor(0.0, 0.0, 0.0, 0.0);
    //平滑着色
    glShadeModel(GL_FLAT);
    //启用深度缓存
    glEnable(GL_DEPTH_TEST);

    makeCheckImage();
    //设置纹理图片封包解包的对其方式，1字节对齐， 即每行存储的字节数必须是1的整数倍
    glPixelStorei(GL_UNPACK_ALIGNMENT, 1);

    //s，t方向超过1纹理重复
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);

    //当所显示的纹理比加载进来的纹理大或小时，采用GL_NEAREST的方法来处理
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);


    //载入二维纹理图像
    glTexImage2D(GL_TEXTURE_2D, 0, 4, checkImageWidth, checkImageHeight,
                 0, GL_RGBA, GL_UNSIGNED_BYTE, checkImage);
}


void reshape(int w, int h)
{
   //设置视口大小
   glViewport(0, 0, (GLsizei) w, (GLsizei) h);
   //载入投影矩阵
   glMatrixMode(GL_PROJECTION);
   //当前矩阵单位化
   glLoadIdentity();
   //设置透视投影
   gluPerspective(60.0, (GLfloat) w/(GLfloat) h, 1.0, 30.0);
   //载入模型矩阵
   glMatrixMode(GL_MODELVIEW);
   glLoadIdentity();
   //摄像机在原点，把模型向z轴平移 3.6，不然看不到或看不全。
   glTranslatef(0.0, 0.0, -3.6);
}


void display(void)
{
    //清除深度缓存，颜色缓存
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
    //启用2d纹理
    glEnable(GL_TEXTURE_2D);
    //设置纹理和材料颜色混合
    glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_DECAL);


    //画两个面
    glBegin(GL_QUADS);
    glTexCoord2f(0.0, 0.0); glVertex3f(-2.0, -1.0, 0.0);
    glTexCoord2f(0.0, 5.0); glVertex3f(-2.0, 1.0, 0.0);
    glTexCoord2f(5.0, 5.0); glVertex3f(0.0, 1.0, 0.0);
    glTexCoord2f(5.0, 0.0); glVertex3f(0.0, -1.0, 0.0);

    glTexCoord2f(0.0, 0.0); glVertex3f(1.0, -1.0, 0.0);
    glTexCoord2f(0.0, 1.0); glVertex3f(1.0, 1.0, 0.0);
    glTexCoord2f(1.0, 1.0); glVertex3f(2.41421, 1.0, -1.41421);
    glTexCoord2f(1.0, 0.0); glVertex3f(2.41421, -1.0, -1.41421);
    glEnd();
    glFlush();
    glDisable(GL_TEXTURE_2D);

}

void keyboard (unsigned char key, int x, int y)
{
    //设置纹理滤波
   switch (key) {
      case 's':
         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP);
         glutPostRedisplay();
         break;
      case 'S':
         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
         glutPostRedisplay();
         break;
      case 't':
         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP);
         glutPostRedisplay();
         break;
      case 'T':
         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
         glutPostRedisplay();
         break;

      case 'a':
         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
         glutPostRedisplay();
         break;
      case 'A':
        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
        glutPostRedisplay();
        break;

      case 'e':
         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
         glutPostRedisplay();
         break;

      case 'E':
         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
         glutPostRedisplay();
         break;

      case 27:
         exit(0);
         break;
      default:
         break;
   }
}

int main(int argc, char *argv[])
{
    glutInit(&argc, argv);
    glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB | GLUT_DEPTH);
    glutInitWindowSize(250, 250);
    glutInitWindowPosition(100, 100);
    glutCreateWindow(argv[0]);
    init();
    glutDisplayFunc(display);
    glutReshapeFunc(reshape);
    glutKeyboardFunc(keyboard);
    glutMainLoop();
    return 0;
}