教室漫游代码⽂档

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[TOC]

程序实现功能

使⽤OpenGL编程实现室内场景的漫游，要求⽤户可⾃由选择观看位置和视线⽅向。

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代码结构

• 库⽂件

#include<gl/glut.h> #include<windows.h> #include<math.h> #include <stdio.h> #include <stdlib.h> #pragma warning(disable:4996)

• 结构体

typedef struct EyePoint {

GLfloat x;

GLfloat y;

GLfloat z; }EyePoint;

EyePoint myEye; 
EyePoint vPoint; 
EyePoint up; 
GLfloat vAngle = 0;

Eyepoint结构的作⽤是确定当前视⻆，包含x，y，z三个GLfloat变量，我们⽤此结构体来定义三个结构体变量:

- myEye:相当于相机在世界坐标的位置，如果把相机想象成⾃⼰的脑袋，那么它就是脑袋所在的 位置 
- vPoint:相当于相机镜头对准的物体在世界坐标的位置，或者说是眼睛看的物体的位置 
- up:相机向上的⽅向在世界坐标中的⽅向，也就是头顶朝向的⽅向（因为你可以歪着头看同⼀个 物体）
- vAngle:⻆度

• 纹理对象

//定义各个纹理对象的名称
GLuint texblackboard, texwindow, texdesk, texsound; 
GLuint texceiling, texdoor, texfloor, texbackwall, texpole; 
GLuint texairfro, texairback, texhighland, texsdesk, texclock, texcsc,texcuc,texlmy;

此处定义了后⾯要使⽤的纹理对象的名称

• 各函数功能

/*******载⼊位图作为纹理的相关函数 *****/ 
#define BMP_Header_Length 54//定义BMP 头⽂件⼤⼩为54
int power_of_two(int n)//判断⼀个数是否是2 的整数次⽅
GLuint load_texture(const char* file_name)// 载⼊BMP图作为纹理，并返回纹理编号
/*********************************/ 
void drawscence()// 绘制教室这个⼤场景
void drawdesks()// 绘制桌⼦
void drawchairs()// 绘制椅⼦
void reshape(int we, int he)// 
void myDisplay()// 窗⼝刷新函数，包括视⻆的刷新 显示函数，⽤来显示教室、桌⼦以及椅⼦
GLvoid OnKeyboard(unsigned char key, int x, int y)// 响应普通键盘操作，w ，s ，a ，d 以及退出esc 键
GLvoid OnUPDOWN(int key, int x, int y)//响应特殊键盘操作，即上下左右

• 函数实现

int power_of_two(int n)

int power_of_two(int n) {

if (n <= 0)

return 0;

return (n & (n - 1)) == 0; }

这个函数⽤来判断⼀个数是否为2的整数次⽅，如果是⼩于等于0，那么直接返回0，说明它不是2的整数次 ⽅；否则我们对它进⾏ &位运算，如果它是2的整数次⽅，那么它的⼆进制必定是1（0）*的格式，那么这个 数减去⼀的话，⼆进制就变成了0（1）*的格式，这时对它们进⾏&运算，如果为0的话，说明这各数是2的整 数次⽅，所以返回0==0，值为1，否则返回0.

GLuint load_texture(const char* file_name)

GLuint load_texture(const char* file_name)
{
	GLint width, height, total_bytes;
	GLubyte* pixels = 0;
	GLuint last_texture_ID = 0, texture_ID = 0;

	// 打开文件，如果失败，返回    
	FILE* pFile = fopen(file_name, "rb");
	if (pFile == 0)
		return 0;

	// 读取文件中图象的宽度和高度    
	fseek(pFile, 0x0012, SEEK_SET);
	fread(&width, 4, 1, pFile);
	fread(&height, 4, 1, pFile);
	fseek(pFile, BMP_Header_Length, SEEK_SET);

	// 计算每行像素所占字节数，并根据此数据计算总像素字节数    
	{
		GLint line_bytes = width * 3;
		while (line_bytes % 4 != 0)
			++line_bytes;
		total_bytes = line_bytes * height;
	}

	// 根据总像素字节数分配内存    
	pixels = (GLubyte*)malloc(total_bytes);
	if (pixels == 0)
	{
		fclose(pFile);
		return 0;
	}

	// 读取像素数据    
	fread(pixels, total_bytes, 1, pFile);

	// 对就旧版本的兼容，如果图象的宽度和高度不是2的整数次方，则需要进行缩放    
	// 若图像宽高超过了OpenGL规定的最大值，也缩放    
	{
		GLint max;
		glGetIntegerv(GL_MAX_TEXTURE_SIZE, &max);
		if (power_of_two(width)
			|| power_of_two(height)
			|| width > max
			|| height > max)
		{
			const GLint new_width = 256;
			const GLint new_height = 256; // 规定缩放后新的大小为边长的正方形    
			GLint new_line_bytes, new_total_bytes;
			GLubyte* new_pixels = 0;

			// 计算每行需要的字节数和总字节数    
			new_line_bytes = new_width * 3;
			while (new_line_bytes % 4 != 0)
				++new_line_bytes;
			new_total_bytes = new_line_bytes * new_height;

			// 分配内存    
			new_pixels = (GLubyte*)malloc(new_total_bytes);
			if (new_pixels == 0)
			{
				free(pixels);
				fclose(pFile);
				return 0;
			}

			// 进行像素缩放    
			gluScaleImage(GL_RGB,
				width, height, GL_UNSIGNED_BYTE, pixels,
				new_width, new_height, GL_UNSIGNED_BYTE, new_pixels);

			// 释放原来的像素数据，把pixels指向新的像素数据，并重新设置width和height    
			free(pixels);
			pixels = new_pixels;
			width = new_width;
			height = new_height;
		}
	}

	// 分配一个新的纹理编号    
	glGenTextures(1, &texture_ID);
	if (texture_ID == 0)
	{
		free(pixels);
		fclose(pFile);
		return 0;
	}
	// 在绑定前，先获得原来绑定的纹理编号，以便在最后进行恢复    
	GLint lastTextureID = last_texture_ID;
	glGetIntegerv(GL_TEXTURE_BINDING_2D, &lastTextureID);
	glBindTexture(GL_TEXTURE_2D, texture_ID);

	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR);
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR_MIPMAP_LINEAR);
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
	glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_REPLACE);

	gluBuild2DMipmaps(GL_TEXTURE_2D, 3, width, height, GL_BGR_EXT, GL_UNSIGNED_BYTE, pixels);

	glBindTexture(GL_TEXTURE_2D, lastTextureID);  //恢复之前的纹理绑定    
	free(pixels);
	return texture_ID;
}

此函数用于实现载入BMP图作为纹理，并返回纹理编号。首 先定义bmp文件的宽度和高度，像素值，以及两个纹理编号，其中last Texture ID用来存储之前绑定的纹理编号，以便在最后进行回恢复。然后我们打开bmp文件，读取图像的宽度和高度，然后计算每行像素所占的像素值，彩色bmp图为三位，因此将宽度乘3,因为每一行像素值必须是4的倍数，因此不够的我们要进行填充，最后乘上高度就是bmp文件像素值的字节大小了。根据得到的值为pixels分配内存，然后将bmp图像像素数据存放到pixels中。在这里，我们需要注意一个情况:如果图像的宽度和高度不是2的整数次方，或者图像的宽高超过了OpenGL的最大值，也需要进行缩放。因此我们需要比较宽高和OpenGI的最大值max，并且用前面定义的power_of_two来判断宽高是否时候2的整数次方。如果不满足条件，则我们重新定义一个宽高以及像素值，重新计算字节大小和分配内存。最后使用gluScalelmage函数进行像素缩放，这样就得到了符合标准的pixels。在这之后，我们需要使用glGenTextures函数给这个文件分配一个新的纹理编号。在绑定之前，先获得原来的纹理编号，以便在最后进行恢复。最后使用glTexParameteri函 数确定如何把纹理象素映射成像素.

GL_TEXTURE_2D: 操作2D纹理. GL_TEXTURE_WRAP_S: S方向上的贴图模式. GL_TEXTURE_WRAP_T: T方向上的贴图模式 GL_TEXTURE_MIN_FILTER: 缩小过滤 GL_LINEAR_MIPMAP_ NEAREST:使用GL_NEAREST对最接近当前多边形的解析度的两个层级贴图进行采样,然后用这两个值进行线性插值

最后使⽤gluBuild2DMipmaps构建2D纹理，最后恢复之前的纹理编号，释放pixels内存，返回纹理编号.

void drawscence()

void drawscence()
{


	/*glTexCoord2f绘制图形时指定纹理的坐标，第一个是X轴坐标，0.0是纹理的左侧，0.5是纹理的中点，1.0是纹理的右侧，
	第二个是Y轴坐标，0.0是纹理的底部，0.5是纹理的中点，1.0是纹理的顶部，
	为了将纹理正确的映射到四边形上，您必须将纹理的右上角映射到四边形的右上角，纹理的左上角映射到四边形的左上角，
	纹理的右下角映射到四边形的右下角，纹理的左下角映射到四边形的左下角，纹理的左上坐标是X：0.0，Y：1.0f，四边形的左上顶点是X：-1.0，Y：1.0。*/
	
	
	glEnable(GL_TEXTURE_2D);//开启2D纹理功能
	//天花板
	glBindTexture(GL_TEXTURE_2D, texceiling);//绑定纹理
	glBegin(GL_QUADS);//画四边形
	glTexCoord2f(0.0f, 0.0f); glVertex3f(-40.0f, 30.0f, 30.0f);//左下
	glTexCoord2f(0.0f, 1.0f); glVertex3f(-40.0f, 30.0f, -30.0f);//左上
	glTexCoord2f(1.0f, 1.0f); glVertex3f(40.0f, 30.0f, -30.0f);//右上
	glTexCoord2f(1.0f, 0.0f); glVertex3f(40.0f, 30.0f, 30.0f);//右下
	glEnd();


	//绘制地板
	glBindTexture(GL_TEXTURE_2D, texfloor);
	glBegin(GL_QUADS);
	glTexCoord2f(1.0f, 0.0f); glVertex3f(-40.0f, 0.0f, 30.0f);
	glTexCoord2f(1.0f, 1.0f); glVertex3f(-40.0f, 0.0f, -30.0f);
	glTexCoord2f(0.0f, 1.0f); glVertex3f(40.0f, 0.0f, -30.0f);
	glTexCoord2f(0.0f, 0.0f); glVertex3f(40.0f, 0.0f, 30.0f);
	glEnd();

	//绘制左边墙
	glBindTexture(GL_TEXTURE_2D, texbackwall);
	glBegin(GL_QUADS);
	glNormal3f(1.0f, 0.0f, 0.0f);
	glTexCoord2f(1.0f, 0.0f); glVertex3f(-40.0f, 0.0f, 30.0f);
	glTexCoord2f(1.0f, 1.0f); glVertex3f(-40.0f, 30.0f, 30.0f);
	glTexCoord2f(0.0f, 1.0f); glVertex3f(-40.0f, 30.0f, -30.0f);
	glTexCoord2f(0.0f, 0.0f); glVertex3f(-40.0f, 0.0f, -30.0f);
	glEnd();

	//绘制左边窗户
	glBindTexture(GL_TEXTURE_2D, texwindow);
	for (int n = 0; n <= 1; n++)
	{
		glBegin(GL_QUADS);
		glNormal3f(1.0, 0.0f, 0.0f);
		glTexCoord2f(1.0f, 0.0f); glVertex3f(-39.9, 10, -8 + n * 18);
		glTexCoord2f(1.0f, 1.0f); glVertex3f(-39.9, 20, -8 + n * 18);
		glTexCoord2f(0.0f, 1.0f); glVertex3f(-39.9, 20, -18 + n * 18);
		glTexCoord2f(0.0f, 0.0f); glVertex3f(-39.9, 10, -18 + n * 18);
		glEnd();
	}

	//绘制右边墙
	glBindTexture(GL_TEXTURE_2D, texbackwall);
	glBegin(GL_QUADS);
	glNormal3f(-1.0f, 0.0f, 0.0f); //用于定义法线向量
	glTexCoord2f(1.0f, 0.0f); glVertex3f(40.0f, 0.0f, 30.0f);
	glTexCoord2f(1.0f, 1.0f); glVertex3f(40.0f, 30.0f, 30.0f);
	glTexCoord2f(0.0f, 1.0f); glVertex3f(40.0f, 30.0f, -30.0f);
	glTexCoord2f(0.0f, 0.0f); glVertex3f(40.0f, 0.0f, -30.0f);
	glEnd();

	//绘制右边窗户
	glBindTexture(GL_TEXTURE_2D, texwindow);
	glBegin(GL_QUADS);
	glNormal3f(-1.0, 0.0f, 0.0f);	                  //用于定义法线向量
	glTexCoord2f(1.0f, 0.0f); glVertex3f(39.5, 10, 10);
	glTexCoord2f(1.0f, 1.0f); glVertex3f(39.5, 20, 10);
	glTexCoord2f(0.0f, 1.0f); glVertex3f(39.5, 20, 0);
	glTexCoord2f(0.0f, 0.0f); glVertex3f(39.5, 10, 0);
	glEnd();

	//绘制后边墙
	glBindTexture(GL_TEXTURE_2D, texbackwall);
	glBegin(GL_QUADS);
	glNormal3f(0.0f, 0.0f, 1.0f); //用于定义法线向量
	glTexCoord2f(0.0f, 0.0f); glVertex3f(-40.0f, 0.0f, 30.0f);
	glTexCoord2f(0.0f, 1.0f); glVertex3f(-40.0f, 30.0f, 30.0f);
	glTexCoord2f(1.0f, 1.0f); glVertex3f(40.0f, 30.0f, 30.0f);
	glTexCoord2f(1.0f, 0.0f); glVertex3f(40.0f, 0.0f, 30.0f);
	glEnd();

	//CUC
	glBindTexture(GL_TEXTURE_2D, texcuc);
	glBegin(GL_QUADS);
	glNormal3f(0.0f, 0.0f, 1.0f); //用于定义法线向量
	glTexCoord2f(1.0f, 0.0f); glVertex3f(-4.8f, 15.0f, 30.0f);
	glTexCoord2f(1.0f, 1.0f); glVertex3f(-4.8f, 20.0f, 30.0f);
	glTexCoord2f(0.0f, 1.0f); glVertex3f(4.8f, 20.0f, 30.0f);
	glTexCoord2f(0.0f, 0.0f); glVertex3f(4.8f, 15.0f, 30.0f);
	glEnd();

	//CSC
	glBindTexture(GL_TEXTURE_2D, texcsc);
	glBegin(GL_QUADS);
	glNormal3f(0.0f, 0.0f, 1.0f); //用于定义法线向量
	glTexCoord2f(1.0f, 0.0f); glVertex3f(-15.0f, 10.0f, 30.0f);
	glTexCoord2f(1.0f, 1.0f); glVertex3f(-15.0f, 15.0f, 30.0f);
	glTexCoord2f(0.0f, 1.0f); glVertex3f(15.0f, 15.0f, 30.0f);
	glTexCoord2f(0.0f, 0.0f); glVertex3f(15.0f, 10.0f, 30.0f);
	glEnd();

	//绘制前边墙
	glBindTexture(GL_TEXTURE_2D, texbackwall);
	glBegin(GL_QUADS);
	glTexCoord2f(0.0f, 0.0f); glVertex3f(-40.0f, 0.0f, -30.0f);
	glTexCoord2f(0.0f, 1.0f); glVertex3f(-40.0f, 30.0f, -30.0f);
	glTexCoord2f(1.0f, 1.0f); glVertex3f(40.0f, 30.0f, -30.0f);
	glTexCoord2f(1.0f, 0.0f); glVertex3f(40.0f, 0.0f, -30.0f);
	glEnd();

	//画钟
	glBindTexture(GL_TEXTURE_2D, texclock);
	glBegin(GL_QUADS);
	glTexCoord2f(0.0f, 0.0f); glVertex3f(23.0f, 18.0f, -29.8f);
	glTexCoord2f(0.0f, 1.0f); glVertex3f(23.0f, 20.0f, -29.8f);
	glTexCoord2f(1.0f, 1.0f); glVertex3f(25.0f, 20.0f, -29.8f);
	glTexCoord2f(1.0f, 0.0f); glVertex3f(25.0f, 18.0f, -29.8f);
	glEnd();

	//绘制空调
	glBindTexture(GL_TEXTURE_2D, texairfro);
	glBegin(GL_QUADS);
	glNormal3f(0.0f, 0.0f, 1.0f);
	glTexCoord2f(0.0f, 0.0f); glVertex3f(33.0f, 0.0f, -26.0f);
	glTexCoord2f(0.0f, 1.0f); glVertex3f(33.0f, 15.0f, -26.0f);
	glTexCoord2f(1.0f, 1.0f); glVertex3f(37.0f, 15.0f, -26.0f);
	glTexCoord2f(1.0f, 0.0f); glVertex3f(37.0f, 0.0f, -26.0f);
	glEnd();

	glBindTexture(GL_TEXTURE_2D, texairback);
	glBegin(GL_QUADS);
	glNormal3f(-1.0f, 0.0f, 0.0f);
	glTexCoord2f(0.0f, 0.0f); glVertex3f(33.0f, 0.0f, -26.0f);
	glTexCoord2f(0.0f, 1.0f); glVertex3f(33.0f, 15.0f, -26.0f);
	glTexCoord2f(1.0f, 1.0f); glVertex3f(33.0f, 15.0f, -29.0f);
	glTexCoord2f(1.0f, 0.0f); glVertex3f(33.0f, 0.0f, -29.0f);
	glEnd();

	//绘制教室两边石柱前边两根
	glBindTexture(GL_TEXTURE_2D, texpole);
	for (int i = 0; i <= 1; i++)
	{
		glColor3f(1.0f, 1.0f, 1.0f);
		//glColor3f(255, 255, 255);
		//石柱上表面
		glBegin(GL_QUADS);
		glNormal3f(0.0f, -1.0f, 0.0f); //用于定义法线向量
		glTexCoord2f(0.0f, 0.0f); glVertex3f(-40.0 + i * 78, 30.0f, -4.0f);
		glTexCoord2f(1.0f, 0.0f); glVertex3f(-40.0 + i * 78, 30.0f, -6.0f);
		glTexCoord2f(1.0f, 1.0f); glVertex3f(-38.0 + i * 78, 30.0f, -6.0f);
		glTexCoord2f(0.0f, 1.0f); glVertex3f(-38.0f + i * 78, 30.0f, -4.0f);
		glEnd();
		//石柱前表面
		glBegin(GL_QUADS);
		glNormal3f(0.0f, 0.0f, 1.0f); //用于定义法线向量
		glTexCoord2f(0.0f, 0.0f); glVertex3f(-40.0 + i * 78, 0.0f, -4.0f);
		glTexCoord2f(0.0f, 1.0f); glVertex3f(-40.0 + i * 78, 30.0f, -4.0f);
		glTexCoord2f(1.0f, 1.0f); glVertex3f(-38.0 + i * 78, 30.0f, -4.0f);
		glTexCoord2f(1.0f, 0.0f); glVertex3f(-38.0 + i * 78, 0.0f, -4.0f);
		glEnd();
		//石柱后表面
		glBegin(GL_QUADS);
		glNormal3f(0.0f, 0.0f, -1.0f); //用于定义法线向量
		glTexCoord2f(0.0f, 0.0f); glVertex3f(-40.0 + i * 78, 0.0f, -6.0f);
		glTexCoord2f(0.0f, 1.0f); glVertex3f(-40.0 + i * 78, 30.0f, -6.0f);
		glTexCoord2f(1.0f, 1.0f); glVertex3f(-38.0 + i * 78, 30.0f, -6.0f);
		glTexCoord2f(1.0f, 0.0f); glVertex3f(-38.0 + i * 78, 0.0f, -6.0f);
		glEnd();
		//石柱右表面
		glBegin(GL_QUADS);
		glNormal3f(0.0f, 0.0f, -1.0f); //用于定义法线向量
		glTexCoord2f(0.0f, 0.0f); glVertex3f(-38.0 + i * 76, 0.0f, -4.0f);
		glTexCoord2f(0.0f, 1.0f); glVertex3f(-38.0 + i * 76, 30.0f, -4.0f);
		glTexCoord2f(1.0f, 1.0f); glVertex3f(-38.0 + i * 76, 30.0f, -6.0f);
		glTexCoord2f(1.0f, 0.0f); glVertex3f(-38.0 + i * 76, 0.0f, -6.0f);
		glEnd();
	}
	//绘制教室两边石柱，后边两根
	for (int j = 0; j <= 1; j++)
	{

		glColor3f(1.0f, 1.0f, 1.0f);
		//glColor3f(255, 255, 255);
		//石柱上表面
		glBegin(GL_QUADS);
		glNormal3f(0.0f, -1.0f, 0.0f); //用于定义法线向量
		glTexCoord2f(0.0f, 0.0f); glVertex3f(-40.0 + j * 78, 30.0f, 14.0f);
		glTexCoord2f(0.0f, 1.0f); glVertex3f(-40.0 + j * 78, 30.0f, 12.0f);
		glTexCoord2f(1.0f, 1.0f); glVertex3f(-38.0 + j * 78, 30.0f, 12.0f);
		glTexCoord2f(1.0f, 0.0f); glVertex3f(-38.0f + j * 78, 30.0f, 14.0f);
		glEnd();
		//石柱前表面
		glBegin(GL_QUADS);
		glNormal3f(0.0f, 0.0f, 1.0f); //用于定义法线向量
		glTexCoord2f(0.0f, 0.0f); glVertex3f(-40.0 + j * 78, 0.0f, 14.0f);
		glTexCoord2f(0.0f, 1.0f); glVertex3f(-40.0 + j * 78, 30.0f, 14.0f);
		glTexCoord2f(1.0f, 1.0f); glVertex3f(-38.0 + j * 78, 30.0f, 14.0f);
		glTexCoord2f(1.0f, 0.0f); glVertex3f(-38.0 + j * 78, 0.0f, 14.0f);
		glEnd();
		//石柱后表面
		glBegin(GL_QUADS);
		glNormal3f(0.0f, 0.0f, -1.0f); //用于定义法线向量
		glTexCoord2f(0.0f, 0.0f); glVertex3f(-40.0 + j * 78, 0.0f, 12.0f);
		glTexCoord2f(0.0f, 1.0f); glVertex3f(-40.0 + j * 78, 30.0f, 12.0f);
		glTexCoord2f(1.0f, 1.0f); glVertex3f(-38.0 + j * 78, 30.0f, 12.0f);
		glTexCoord2f(1.0f, 0.0f); glVertex3f(-38.0 + j * 78, 0.0f, 12.0f);
		glEnd();
		//右表面
		glBegin(GL_QUADS);
		glNormal3f(0.0f, 0.0f, -1.0f); //用于定义法线向量
		glTexCoord2f(0.0f, 0.0f); glVertex3f(-38.0 + j * 76, 0.0f, 14.0f);
		glTexCoord2f(0.0f, 1.0f); glVertex3f(-38.0 + j * 76, 30.0f, 14.0f);
		glTexCoord2f(1.0f, 1.0f); glVertex3f(-38.0 + j * 76, 30.0f, 12.0f);
		glTexCoord2f(1.0f, 0.0f); glVertex3f(-38.0 + j * 76, 0.0f, 12.0f);
		glEnd();
	}

	//绘制黑板
	glBindTexture(GL_TEXTURE_2D, texblackboard);
	glBegin(GL_QUADS);
	glNormal3f(0.0f, 0.0f, 1.0f); //用于定义法线向量
	glTexCoord2f(0.0f, 0.0f); glVertex3f(-20.0, 8.0f, -29.9f);
	glTexCoord2f(0.0f, 1.0f); glVertex3f(-20.0, 18.0f, -29.9f);
	glTexCoord2f(1.0f, 1.0f); glVertex3f(20.0, 18.0f, -29.9f);
	glTexCoord2f(1.0f, 0.0f); glVertex3f(20.0, 8.0f, -29.9f);
	glEnd();

	//lmy
	glBindTexture(GL_TEXTURE_2D, texlmy);
	glBegin(GL_QUADS);
	glNormal3f(0.0f, 0.0f, 1.0f); //用于定义法线向量
	glTexCoord2f(0.0f, 0.0f); glVertex3f(-5.0, 20.0f, -29.9f);
	glTexCoord2f(0.0f, 1.0f); glVertex3f(-5.0, 25.0f, -29.9f);
	glTexCoord2f(1.0f, 1.0f); glVertex3f(5.0, 25.0f, -29.9f);
	glTexCoord2f(1.0f, 0.0f); glVertex3f(5.0, 20.0f, -29.9f);
	glEnd();
	
	//绘制教室前边一块高地并贴纹理
	glBindTexture(GL_TEXTURE_2D, texhighland);
	//贴上面
	glBegin(GL_QUADS);
	glNormal3f(0.0f, 1.0f, 0.0f); //用于定义法线向量
	glTexCoord2f(0.0f, 0.0f); glVertex3f(-30.0f, 1.5f, -22.0f);
	glTexCoord2f(0.0f, 1.0f); glVertex3f(-30.0f, 1.5f, -30.0f);
	glTexCoord2f(1.0f, 1.0f); glVertex3f(30.0f, 1.5f, -30.0f);
	glTexCoord2f(1.0f, 0.0f); glVertex3f(30.0f, 1.5f, -22.0f);
	glEnd();
	//贴左边
	glBegin(GL_QUADS);
	glNormal3f(0.0f, 0.0f, 1.0f); //用于定义法线向量
	glTexCoord2f(0.0f, 0.0f); glVertex3f(-30.0f, 0, -22.0f);
	glTexCoord2f(0.0f, 1.0f); glVertex3f(-30.0f, 1.5f, -22.0f);
	glTexCoord2f(1.0f, 1.0f); glVertex3f(-30.0f, 1.5f, -30.0f);
	glTexCoord2f(1.0f, 0.0f); glVertex3f(-30.0f, 0, -30.0f);
	glEnd();
	//贴前边
	glBegin(GL_QUADS);
	glNormal3f(0.0f, 1.0f, 0.0f); //用于定义法线向量
	glTexCoord2f(0.0f, 0.0f); glVertex3f(-30.0f, 0, -22.0f);
	glTexCoord2f(0.0f, 1.0f); glVertex3f(-30.0f, 1.5f, -22.0f);
	glTexCoord2f(1.0f, 1.0f); glVertex3f(30.0f, 1.5f, -22.0f);
	glTexCoord2f(1.0f, 0.0f); glVertex3f(30.0f, 0, -22.0f);
	glEnd();
	//贴右边
	glBegin(GL_QUADS);
	glNormal3f(0.0f, 1.0f, 0.0f); //用于定义法线向量
	glTexCoord2f(0.0f, 0.0f); glVertex3f(30.0f, 0, -22.0f);
	glTexCoord2f(0.0f, 1.0f); glVertex3f(30.0f, 1.5f, -22.0f);
	glTexCoord2f(1.0f, 1.0f); glVertex3f(30.0f, 1.5f, -30.0f);
	glTexCoord2f(1.0f, 0.0f); glVertex3f(30.0f, 0, -30.0f);
	glEnd();
	//绘制讲台
	//贴讲台纹理
	glBindTexture(GL_TEXTURE_2D, texsdesk);
	glBegin(GL_QUADS);
	glNormal3f(0.0f, 1.0f, 0.0f); //用于定义法线向量
	glTexCoord2f(0.0f, 0.0f); glVertex3f(-7.5f, 1.5f, -24.0f);
	glTexCoord2f(0.0f, 1.0f); glVertex3f(-7.5f, 9.5f, -24.0f);
	glTexCoord2f(1.0f, 1.0f); glVertex3f(7.5f, 9.5f, -24.0f);
	glTexCoord2f(1.0f, 0.0f); glVertex3f(7.5f, 1.5f, -24.0f);
	glEnd();
	glBegin(GL_QUADS);
	glNormal3f(0.0f, 1.0f, 0.0f); //用于定义法线向量
	glTexCoord2f(0.0f, 0.0f); glVertex3f(7.5f, 1.5f, -24.0f);
	glTexCoord2f(0.0f, 1.0f); glVertex3f(7.5f, 9.5f, -24.0f);
	glTexCoord2f(1.0f, 1.0f); glVertex3f(7.5f, 9.5f, -28.0f);
	glTexCoord2f(1.0f, 0.0f); glVertex3f(7.5f, 1.5f, -28.0f);
	glEnd();
	glBegin(GL_QUADS);
	glNormal3f(0.0f, 1.0f, 0.0f); //用于定义法线向量
	glTexCoord2f(0.0f, 0.0f); glVertex3f(-7.5f, 1.5f, -24.0f);
	glTexCoord2f(0.0f, 1.0f); glVertex3f(-7.5f, 9.5f, -24.0f);
	glTexCoord2f(1.0f, 1.0f); glVertex3f(-7.5f, 9.5f, -28.0f);
	glTexCoord2f(1.0f, 0.0f); glVertex3f(-7.5f, 1.5f, -28.0f);
	glEnd();
	glBegin(GL_QUADS);
	glNormal3f(0.0f, 1.0f, 0.0f); //用于定义法线向量
	glTexCoord2f(0.0f, 0.0f); glVertex3f(-7.5f, 9.5f, -24.0f);
	glTexCoord2f(0.0f, 1.0f); glVertex3f(-7.5f, 9.5f, -26.0f);
	glTexCoord2f(1.0f, 1.0f); glVertex3f(7.5f, 9.5f, -26.0f);
	glTexCoord2f(1.0f, 0.0f); glVertex3f(7.5f, 9.5f, -24.0f);
	glEnd();
	//画门
	glColor3f(0.521f, 0.121f, 0.0547f);
	glBindTexture(GL_TEXTURE_2D, texdoor);
	glBegin(GL_QUADS);
	glNormal3f(-1.0f, 0.0f, 0.0f); //用于定义法线向量
	glTexCoord2f(0.0f, 0.0f); glVertex3f(39.9f, 0.0f, -25.0f);
	glTexCoord2f(0.0f, 1.0f); glVertex3f(39.9f, 14.0f, -25.0f);
	glTexCoord2f(1.0f, 1.0f); glVertex3f(39.9f, 14.0f, -19.0f);
	glTexCoord2f(1.0f, 0.0f); glVertex3f(39.9f, 0.0f, -19.0f);
	glEnd();
	
	glDisable(GL_TEXTURE_2D);
}

drawscence() 函数⽤于绘制整个教室和⾥⾯的物品装饰（桌⼦，椅⼦除外），包括天花板、地板、⽯柱、 四周墙、窗户、⿊板、钟、空调、讲台、⻔、海报等。。。 由于这⾥每⼀个物件的绘制都⼤致相同，因此我 们将天花板作为例⼦来分析：

glEnable(GL_TEXTURE_2D);//开启2D纹理功能
 //天花板
glBindTexture(GL_TEXTURE_2D, texceiling);//绑定纹理
glBegin(GL_QUADS);//画四边形
glTexCoord2f(0.0f, 0.0f); glVertex3f(-40.0f, 30.0f, 30.0f);//左下
glTexCoord2f(0.0f, 1.0f); glVertex3f(-40.0f, 30.0f, -30.0f);//左上 glTexCoord2f(1.0f, 1.0f); glVertex3f(40.0f, 30.0f, -30.0f);//右上
glTexCoord2f(1.0f, 0.0f); glVertex3f(40.0f, 30.0f, 30.0f);//右下
glEnd();

⾸先我们需要⽤glEnable(GL_TEXTURE_2D)函数来开启2D纹理功能，所以对应的，我们也要在全部纹理贴完 后，在代码最后⽤glDisable(GL_TEXTURE_2D)函数来关闭2D纹理功能。 在开启纹理功能后，我们再⽤ glBindTexture(GL_TEXTURE_2D, texceiling)来绑定对应的天花板纹理， 在这之后，我们需要使⽤到 glTexCoord2f函数和glVertex3f来绘制物体。 glTexCoord2f绘制图形时指定纹理的坐标，第⼀个是X轴坐标， 0.0是纹理的左侧，0.5是纹理的中点，1.0是纹理的右侧， 第⼆个是Y轴坐标，0.0是纹理的底部，0.5是纹理 的中点，1.0是纹理的顶部， 为了将纹理正确的映射到四边形上，您必须将纹理的右上⻆映射到四边形的右上 ⻆，纹理的左上⻆映射到四边形的左上⻆， 纹理的右下⻆映射到四边形的右下⻆，纹理的左下⻆映射到四边 形的左下⻆，纹理的左上坐标是X：0.0，Y：1.0f，四边形的左上顶点是X：-1.0，Y：1.0。 glVertex3f⽤来构 造⼆维平⾯，它也对应这3维空间⾥的4个点，并把这四个点连接起来形成⼀个平⾯。如果构造对应的⼏个 ⾯，就可以围成⼀个⻓⽅体，依此我们就可以去构造更多的物体，例如：⻔、⽯柱、窗户、⿊板。。。 在这 ⾥特殊的有⽯柱和窗户两个物体，因为他们的数量不⽌⼀个，但他们的形状相同，不同的只是在空间中的位 置，因此我们可以使⽤for循环，来改变它们在空间中的x或y或z坐标，来移动他们的位置。

drawdesks() && drawchairs() 此处代码忽略

这⾥的drawdesks()和drawchairs()在本质上都是通过是glVertex3f函数来贴合四边形，以达到构造物体结构的 ⽬的。不同的是在这⾥使⽤了glColor3f函数来设置桌⼦和凳⼦的颜⾊。这⾥的难点并不在于构造物体，⽽是 如何在教室后构造⾜够数量的桌椅，并把它们整⻬地组合在⼀起。

reshape

void reshape(int we, int he)
{

	WinWidth = we;
	WinHeight = he;
	glViewport(0, 0, (GLsizei)we, (GLsizei)he);/*0 0指定了窗口的左下角位置
	//width,height表示视口矩形的宽度和高度，根据窗口的实时变化重绘窗口。*/
	glMatrixMode(GL_PROJECTION);//声明下一步操作为投影
	glLoadIdentity();//恢复初始坐标系
	gluPerspective(90.0f, (GLfloat)we / (GLfloat)he, 0.01f, 100.0f);
	/*透视投影：90.0f近裁剪平面与远裁剪平面的连线与视点的角度,
	也称视场角,0.01f近裁剪面到相机(视点)的距离,100.0f远裁剪面到相机(视点)的距离*/
	glMatrixMode(GL_MODELVIEW);//声明下一步为对模型视图的操作
	glLoadIdentity();
	/*第一组eyex, eyey,eyez 相机在世界坐标的位置(视点)
	第二组centerx,centery,centerz 相机镜头对准的物体在世界坐标的位置
	第三组upx,upy,upz 相机向上的方向在世界坐标中的方向
	把相机想象成为你自己的脑袋：
	第一组数据就是脑袋的位置
	第二组数据就是眼睛看的物体的位置
	第三组就是头顶朝向的方向（因为你可以歪着头看同一个物体）*/
	gluLookAt(myEye.x, myEye.y, myEye.z, vPoint.x + 30 * sin(vAngle), vPoint.y, -30 * cos(vAngle), up.x, up.y, up.z);//0.0f, 1.0f, 0.0f);
}

reshape()函数⽤来实现窗⼝的创建刷新以及视⻆的变换。其中较为重要的就是gluLookAt()函数，我们可以借 助下图来理解

• 第⼀组数据就是脑袋的位置
• 第⼆组数据就是眼睛看的物体的位置
• 第三组就是头顶朝向的⽅向（因为你可以歪着头看同⼀个物体） 其中第⼆组数据，我们使⽤了sin()函 数和设定的全局变量vAngle来调整眼睛看的物体的位置。

myDisplay()

//显示函数
void myDisplay()
{
	// 清除屏幕
	glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
	//调用绘制函数
	drawscence();
	for (int i = -3; i <= 3; i += 2) {
		for (int j = -3; j <= 3; j += 2) {
			glPushMatrix();
			glTranslatef(i * 5.0f, 3.0f, j * 3.0 + 2.2f);
			glScalef(0.8f, 0.8f, 0.5f);
			drawdesks();
			glPopMatrix();
		}
	}
	for (int i = -3; i <= 3; i += 2) {
		for (int j = -3; j <= 3; j += 2) {
			glPushMatrix();
			glTranslatef(i * 5.0f + 0.2f, 3.0f, j * 3.0 + 5.5f);
			glScalef(0.8f, 0.8f, 0.5f);
			drawchairs();
			glPopMatrix();
		}
	}
	glFlush();//清空缓冲区
}

在myDisplay()函数⾥，主要实现了场景的显示功能。⾸先调⽤glClear()函数来清除屏幕，然后调⽤ drawscence()来绘制教室，这⾥较为重要的是在教室中绘制数量⾜够多且排列整⻬的桌椅。 我们在这⾥使⽤ 了两个for循环，通过i和j来实现对桌椅位置的对称移动。 其中glPushMatrix()函数⽤来把当前位置⼊栈，搭配 之后的glPopMatrix()函数，将栈顶的位置出栈，实现了保存原始位置的⽬的。glTranslatef（）函数则通过三 个x，y，z参数来移动到相应的位置，glScalef（）搭配drawdesks()使⽤则是将绘制的desks在相应坐标上伸 缩不同的⼤⼩。通过这⼏个函数的搭配，以及嵌套for循环中i、j的变换，实现了对桌⼦在不同位置上的复 制。 同样，我们在对椅⼦的复制中，只需要将glTranslatef()中的参数适当地进⾏修改，就可以和桌⼦整⻬地 排列在⼀起了。

OnKeyboard() && OnUPDOWN()

//响应普通键盘操作，w，s，a，d以及退出esc键
GLvoid OnKeyboard(unsigned char key, int x, int y)
{
	switch (key)
	{
	case 97://a 向左
		myEye.x -= 0.5;
		vPoint.x -= 0.5;
		if (myEye.x <= -38)
			myEye.x = -38;
		break;
	case 100://d 向右
		myEye.x += 0.5;
		vPoint.x += 0.5;
		if (myEye.x >= 38)
			myEye.x = 38;
		break;
	case 119://w 向前
		myEye.z -= 0.5;
		if (myEye.z <= -28)
			myEye.z = -28;
		break;
	case 115://s 向后
		myEye.z += 0.5;
		if (myEye.z >= 28)
			myEye.z = 28;
		break;
	case 27://esc
		exit(0);

	}
	reshape(WinWidth, WinHeight);//窗口刷新
	glutPostRedisplay();

}
//响应特殊键盘操作
GLvoid OnUPDOWN(int key, int x, int y)//上下左右
{
	switch (key)
	{
	case GLUT_KEY_LEFT:
		vAngle -= 0.05;
		break;
	case GLUT_KEY_RIGHT:
		vAngle += 0.05;
		break;
	case GLUT_KEY_UP:
		myEye.y += 0.5;
		if (myEye.y >= 30)
			myEye.y = 30;

		break;
	case GLUT_KEY_DOWN:
		myEye.y -= 0.5;
		if (myEye.y <= 0)
			myEye.y = 30;
		break;
	}
	reshape(WinWidth, WinHeight);
	glutPostRedisplay();
}

OnKeyboard()函数⽤来响应普通键盘操作，w，s，a，d以及退出esc键，我们对wsad四个键设置了不同的反 应，⽤来控制myEye和vPoint的参数变化，也就是脑袋位置和眼睛所看位置的变化。同时，还加⼊了碰撞检 测，如果超过所设定的边界，则不可以再移动了。ese键则对应exit(0)，⽤来退出程序。 同样的， OnUPDOWN(）函数⽤来响应上下左右键，改变vAngle和myEye的值。同样的，我们在上下键中也加⼊了碰 撞检测。

main()

int main(int argc, char* argv[])
{
	myEye.x = 0;
	myEye.y = 15;
	myEye.z = 25;
	vPoint.x = 0;
	vPoint.y = 15;
	vPoint.z = -30;
	up.x = 0;
	up.y = 1;
	up.z = 0;
	vAngle = 0;
	glEnable(GL_DEPTH_TEST);//启用了之后，OpenGL在绘制的时候就会检查，当前像素前面是否有别的像素，如果别的像素挡道了它，那它就不会绘制，也就是说，OpenGL就只绘制最前面的一层。
	glutInit(&argc, argv);
	glutInitDisplayMode(GLUT_RGBA | GLUT_SINGLE);//定义显示方式，GLUT_RGBA指定一个RGBA窗口，GLUT_SINGLE.单缓冲区窗口
	glutInitWindowPosition(0, 0);//设置初始窗口的位置
	glutInitWindowSize(800, 600);//设置窗口大小
	glutCreateWindow("classroom");
	glutDisplayFunc(&myDisplay);//注册显示回调函数,包含重绘场景所需的所有代码
	glutReshapeFunc(reshape);//注册窗口改变回调函数
	glutKeyboardFunc(OnKeyboard);//注册键盘响应事件
	glutSpecialFunc(OnUPDOWN);//对键盘上特殊的4个方向按键的响应函数

	texblackboard = load_texture("blackboard.bmp");
	texwindow = load_texture("window.bmp");
	texsound = load_texture("sound.bmp");
	texceiling = load_texture("ceiling.bmp");
	texdoor = load_texture("door.bmp");
	texfloor = load_texture("floor.bmp");
	texbackwall = load_texture("backwall.bmp");
	texpole = load_texture("pole.bmp");
	texairfro = load_texture("airconditionfront.bmp");
	texairback = load_texture("airconditionback.bmp");
	texhighland = load_texture("gaodi.bmp");
	texsdesk = load_texture("sdesk.bmp");
	texclock = load_texture("clock.bmp");
	texcuc = load_texture("CUC.bmp");
	texcsc = load_texture("CSC.bmp");
	texlmy = load_texture("lmy.bmp");

	glutMainLoop();//进入事件处理循环
	return 0;
}

在主函数中，我们定义了三个结构体myEye、vPoint、up和vAngle的值，然后开启OpenGL(调⽤各种初始化 函数），设置显示窗⼝的各项数值，注册显示回调函数,包含重绘场景所需的所有代码，注册窗⼝改变回调函 数，注册键盘响应事件，对键盘上特殊的4个⽅向按键的响应函数

---

效果展示

• 进入教室

• 后方

• 俯视

• 教室左侧

• 教室一角

• 讲台纹理细节

• 后方