3. 在屏幕上绘制一个底是正方形的五面锥体，锥体的底面在XOZ平面上，锥顶在Y轴上。用下图给锥体的四个三角形面做纹理映射，使得锥体的四个面分别是红橙黄绿色。

#define GLUT_DISABLE_ATEXIT_HACK

#include "windows.h"
#include <gl/glut.h>
#include "math.h"


float angle = 0;
/** 再定义一个默认的光源 */
static float ambientLight[] = { 0.0f, 1.0f, 0.0f, 1.0f };
static float diffuseLight[] = { 0.8f, 0.8f, 0.8f, 1.0f };
static float specularLight[] = { 1.0f, 1.0f, 1.0f, 1.0f };
static float lightPosition[] = { 0.0f, 0.0f, 5.0f, 1.0f };

BYTE* gltReadBMPBits(const char* szFileName, int* nWidth, int* nHeight)
{
	HANDLE hFileHandle;
	BITMAPINFO* pBitmapInfo = NULL;
	unsigned long lInfoSize = 0;
	unsigned long lBitSize = 0;
	BYTE* pBits = NULL;					// Bitmaps bits
	BITMAPFILEHEADER	bitmapHeader;
	DWORD dwBytes;

	// Open the Bitmap file
	hFileHandle = CreateFile(szFileName, GENERIC_READ, FILE_SHARE_READ,
		NULL, OPEN_EXISTING, FILE_FLAG_SEQUENTIAL_SCAN, NULL);

	// Check for open failure (most likely file does not exist).
	if (hFileHandle == INVALID_HANDLE_VALUE)
		return NULL;

	// File is Open. Read in bitmap header information
	ReadFile(hFileHandle, &bitmapHeader, sizeof(BITMAPFILEHEADER),
		&dwBytes, NULL);

	// Check for a couple of simple errors	
	if (dwBytes != sizeof(BITMAPFILEHEADER))
		return FALSE;

	// Check format of bitmap file
	if (bitmapHeader.bfType != 'MB')
		return FALSE;

	// Read in bitmap information structure
	lInfoSize = bitmapHeader.bfOffBits - sizeof(BITMAPFILEHEADER);
	pBitmapInfo = (BITMAPINFO*)malloc(sizeof(BYTE) * lInfoSize);
	ReadFile(hFileHandle, pBitmapInfo, lInfoSize, &dwBytes, NULL);

	if (dwBytes != lInfoSize)
	{
		free(pBitmapInfo);
		CloseHandle(hFileHandle);
		return FALSE;
	}

	// Save the size and dimensions of the bitmap
	*nWidth = pBitmapInfo->bmiHeader.biWidth;
	*nHeight = pBitmapInfo->bmiHeader.biHeight;
	lBitSize = pBitmapInfo->bmiHeader.biSizeImage;

	// If the size isn't specified, calculate it anyway	
	if (pBitmapInfo->bmiHeader.biBitCount != 24)
	{
		free(pBitmapInfo);
		return FALSE;
	}

	if (lBitSize == 0)
		lBitSize = (*nWidth *
			pBitmapInfo->bmiHeader.biBitCount + 7) / 8 *
		abs(*nHeight);

	// Allocate space for the actual bitmap
	free(pBitmapInfo);
	pBits = (BYTE*)malloc(sizeof(BYTE) * lBitSize);

	// Read in the bitmap bits, check for corruption
	if (!ReadFile(hFileHandle, pBits, lBitSize, &dwBytes, NULL) ||
		dwBytes != (sizeof(BYTE) * lBitSize))
		pBits = NULL;

	// Close the bitmap file now that we have all the data we need
	CloseHandle(hFileHandle);

	return pBits;
}
void DrawCube()
{
	glBegin(GL_TRIANGLES);
		///前侧面
	glNormal3f(0.0f, 2.0f, 4.0f);
	glTexCoord2f(0.0f, 0.0f);	glVertex3f(0.0f, 2.0f, 0.0f);		/**< 三角形的上顶点 (前侧面) */
	glTexCoord2f(0.25f, 0.0f);	glVertex3f(-1.0f, 0.0f, 1.0f);		/**< 三角形的左下顶点 (前侧面) */
	glTexCoord2f(0.125f, 1.0f);	glVertex3f(1.0f, 0.0f, 1.0f);		/**< 三角形的右下顶点 (前侧面) */
		//右侧面
	glNormal3f(4.0f, 2.0f, 0.0f);
	glTexCoord2f(0.5f, 0.0f);	glVertex3f(0.0f, 2.0f, 0.0f);		/**< 三角形的上顶点 (右侧面) */
	glTexCoord2f(0.75f, 0.0f);	glVertex3f(1.0f, 0.0f, 1.0f);		/**< 三角形的左下顶点 (右侧面) */
	glTexCoord2f(0.625f, 1.0f);	glVertex3f(1.0f, 0.0f, -1.0f);		/**< 三角形的右下顶点 (右侧面) */
		///后侧面
	glNormal3f(0.0f, 2.0f, -4.0f);
	glTexCoord2f(0.75f, 0.0f);	glVertex3f(0.0f, 2.0f, 0.0f);		/**< 三角形的上顶点 (后侧面) */
	glTexCoord2f(1.0f, 0.0f);	glVertex3f(1.0f, 0.0f, -1.0f);		/**< 三角形的左下顶点 (后侧面) */
	glTexCoord2f(0.875f, 1.0f);	glVertex3f(-1.0f, 0.0f, -1.0f);		/**< 三角形的右下顶点 (后侧面) */
		///作侧面
	glNormal3f(-4.0f, 2.0f, 0.0f);
	glTexCoord2f(0.375f, 1.0f);	glVertex3f(0.0f, 2.0f, 0.0f);		/**< 三角形的上顶点 (左侧面) */
	glTexCoord2f(0.25f, 0.0f);	glVertex3f(-1.0f, 0.0f, -1.0f);		/**< 三角形的左下顶点 (左侧面) */
	glTexCoord2f(0.5f, 0.0f);	glVertex3f(-1.0f, 0.0f, 1.0f);		/**< 三角形的右下顶点 (左侧面) */
	glEnd();

		///绘制底面四边形	
	glBegin(GL_QUADS);
	glNormal3f(0, -1.0, 0);
	glVertex3f(-1.0f, 0.0f, 1.0f);
	glVertex3f(1.0f, 0.0f, 1.0f);
	glVertex3f(1.0f, 0.0f, -1.0f);
	glVertex3f(-1.0f, 0.0f, -1.0f);
	glEnd();
	glPopMatrix();

}
//初始化OpenGL
void init(void)
{
	glClearColor(0.0f, 0.0f, 0.0f, 0.0f);//设置背景颜色
	glShadeModel(GL_FLAT);//设置明暗处理,有两种选择模式：GL_FLAT（不渐变）和GL_SMOOTH（渐变过渡）
	/** 设置0号光源 */
	glLightfv(GL_LIGHT0, GL_AMBIENT, ambientLight);
	glLightfv(GL_LIGHT0, GL_DIFFUSE, diffuseLight);
	glLightfv(GL_LIGHT0, GL_SPECULAR, specularLight);
	glLightfv(GL_LIGHT0, GL_POSITION, lightPosition);
	glEnable(GL_LIGHTING);
	glEnable(GL_LIGHT0); /**< 启用0号灰色光源,让物体可见 */

	BYTE* pBytes;
	int nWidth, nHeight;
	// 打开位图
	pBytes = gltReadBMPBits(("D:\\003.BMP"), &nWidth, &nHeight);
	// glBindTexture(GL_TEXTURE_2D, textures[0]);
 定义二维纹理
	glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, nWidth, nHeight, 0,
		GL_BGR_EXT, GL_UNSIGNED_BYTE, pBytes);

	//控制滤波
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
	//说明映射方式
	glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);

	glEnable(GL_TEXTURE_2D);

}
//主要的绘制过程
void display(void)
{
	glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);//清除颜色缓存    
	glLoadIdentity();
	glEnable(GL_DEPTH_TEST);

	glColorMaterial(GL_FRONT, GL_DIFFUSE);
	glEnable(GL_COLOR_MATERIAL);

	glTranslatef(0, 0, -10);
	glPushMatrix();
	glRotatef(angle, 1, 1, 0);
	glColor3f(1.0, 1.0, 1.0);

	glColorMaterial(GL_FRONT, GL_DIFFUSE);
	glEnable(GL_COLOR_MATERIAL);
	DrawCube();

	glPopMatrix();
	glFlush();
	glutSwapBuffers();
}
//在窗口改变大小时调用
void reshape(int w, int h) {
	glViewport(0, 0, w, h);//设置视口
	glMatrixMode(GL_PROJECTION);//设置当前为投影变换模式
	glLoadIdentity();//用单位矩阵替换当前变换矩阵
	gluPerspective(45, (float)w / h, 4, 100.0);//设置正交投影视图体
	glMatrixMode(GL_MODELVIEW);
	glLoadIdentity();
}
void TimerFunction(int value)
{
	angle += 10;
	if (angle == 360)
		angle = 0;
		// Redraw the scene with new coordinates
	glutPostRedisplay();
	glutTimerFunc(500, TimerFunction, 1);
}
//处理键盘
void keyboard(unsigned char key, int x, int y) {
	switch (key) {
	case 27://esc键退出
		exit(0);
		break;
	default:
		break;
	}
}
int main(int argc, char* argv[])							//主函数: 参数数量&参数值
{
	glutInit(&argc, argv);
	glutInitWindowSize(640, 480);
	glutCreateWindow("Basic");//设置窗口标题
	init();//初始化OpenGL
	glutDisplayFunc(display);//设置显示回调函数 
	glutReshapeFunc(reshape);//设置reshape回调函数
	glutKeyboardFunc(keyboard);//设置键盘回调函数
	glutTimerFunc(500, TimerFunction, 1);
	glutTimerFunc(500, TimerFunction, 2);
	glutMainLoop();//进入主循环	
}