OpenGL学习十六：纹理绑定

前面介绍的都是给图元添加颜色，纹理绑定介绍的是如果把图片绑定到图元，主要步骤如下：（这里这是简单介绍，后续详细说明）

1.生成纹理ID
glGenTextures(1, &texture[0]);
2.创建纹理对象
glBindTexture(GL_TEXTURE_*D, texture[0]);
3.指定纹理内容
glTexImage*D();
4.指定纹理属性
glTexParameteri(…, ......, …)
5.激活纹理功能
glBindTexture(GL_TEXTURE_*D, texture[0]);
6.提供纹理坐标
glTexCoord*()

 

技巧：纹理贴图以逆时针方式进行：
1.左下（0,0）
2.右下（1,0）
3.左上 (0,1)
4.右上（1,1）

#include "header.h"

GLfloat	xrot;				
GLfloat	yrot;				
GLfloat	zrot;				

GLuint	texture[1];			

AUX_RGBImageRec *LoadBMP(char *Filename)			
{
	FILE *File=NULL;									

	if (!Filename)										
	{
		return NULL;								
	}

	File=fopen(Filename,"r");							

	if (File)											
	{
		fclose(File);									
		return auxDIBImageLoad(Filename);				
	}

	return NULL;										
}

int LoadGLTextures()							
{
	int Status=FALSE;									

	AUX_RGBImageRec *TextureImage[1];					

	memset(TextureImage,0,sizeof(void *)*1);           


	if (TextureImage[0]=LoadBMP("Data/NeHe.bmp"))
	{
		Status=TRUE;									

		glGenTextures(1, &texture[0]);				

		
		glBindTexture(GL_TEXTURE_2D, texture[0]);
		glTexImage2D(GL_TEXTURE_2D, 0, 3, TextureImage[0]->sizeX, TextureImage[0]->sizeY, 0, GL_RGB, GL_UNSIGNED_BYTE, TextureImage[0]->data);
		glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MIN_FILTER,GL_LINEAR);
		glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MAG_FILTER,GL_LINEAR);
	}

	if (TextureImage[0])									
	{
		if (TextureImage[0]->data)						
		{
			free(TextureImage[0]->data);					
		}

		free(TextureImage[0]);						
	}

	return Status;									
}

void ReSizeGLScene(GLsizei width, GLsizei height)		
{
	if (height==0)										
	{
		height=1;									
	}

	glViewport(0,0,width,height);					

	glMatrixMode(GL_PROJECTION);						
	glLoadIdentity();									

	
	gluPerspective(45.0f,(GLfloat)width/(GLfloat)height,0.1f,100.0f);

	glMatrixMode(GL_MODELVIEW);							
	glLoadIdentity();								
}

int InitGL(void)										
{
	if (!LoadGLTextures())							
	{
		return FALSE;									
	}

	glEnable(GL_TEXTURE_2D);							
	glShadeModel(GL_SMOOTH);							
	glClearColor(0.0f, 0.0f, 0.0f, 0.5f);				
	glClearDepth(1.0f);									
	glEnable(GL_DEPTH_TEST);							
	glDepthFunc(GL_LEQUAL);								
	glHint(GL_PERSPECTIVE_CORRECTION_HINT, GL_NICEST);	
	return TRUE;										
}

void DrawGLScene(void)									
{
	glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);	
	glLoadIdentity();									
	glTranslatef(0.0f,0.0f,-5.0f);

	glRotatef(xrot,1.0f,0.0f,0.0f);
	glRotatef(yrot,0.0f,1.0f,0.0f);
	glRotatef(zrot,0.0f,0.0f,1.0f);

	glBindTexture(GL_TEXTURE_2D, texture[0]);

	glBegin(GL_QUADS);
		// Front Face
		glTexCoord2f(0.0f, 0.0f); glVertex3f(-1.0f, -1.0f,  1.0f);
		glTexCoord2f(1.0f, 0.0f); glVertex3f( 1.0f, -1.0f,  1.0f);
		glTexCoord2f(1.0f, 1.0f); glVertex3f( 1.0f,  1.0f,  1.0f);
		glTexCoord2f(0.0f, 1.0f); glVertex3f(-1.0f,  1.0f,  1.0f);
		// Back Face
		glTexCoord2f(1.0f, 0.0f); glVertex3f(-1.0f, -1.0f, -1.0f);
		glTexCoord2f(1.0f, 1.0f); glVertex3f(-1.0f,  1.0f, -1.0f);
		glTexCoord2f(0.0f, 1.0f); glVertex3f( 1.0f,  1.0f, -1.0f);
		glTexCoord2f(0.0f, 0.0f); glVertex3f( 1.0f, -1.0f, -1.0f);
		// Top Face
		glTexCoord2f(0.0f, 1.0f); glVertex3f(-1.0f,  1.0f, -1.0f);
		glTexCoord2f(0.0f, 0.0f); glVertex3f(-1.0f,  1.0f,  1.0f);
		glTexCoord2f(1.0f, 0.0f); glVertex3f( 1.0f,  1.0f,  1.0f);
		glTexCoord2f(1.0f, 1.0f); glVertex3f( 1.0f,  1.0f, -1.0f);
		// Bottom Face
		glTexCoord2f(1.0f, 1.0f); glVertex3f(-1.0f, -1.0f, -1.0f);
		glTexCoord2f(0.0f, 1.0f); glVertex3f( 1.0f, -1.0f, -1.0f);
		glTexCoord2f(0.0f, 0.0f); glVertex3f( 1.0f, -1.0f,  1.0f);
		glTexCoord2f(1.0f, 0.0f); glVertex3f(-1.0f, -1.0f,  1.0f);
		// Right face
		glTexCoord2f(1.0f, 0.0f); glVertex3f( 1.0f, -1.0f, -1.0f);
		glTexCoord2f(1.0f, 1.0f); glVertex3f( 1.0f,  1.0f, -1.0f);
		glTexCoord2f(0.0f, 1.0f); glVertex3f( 1.0f,  1.0f,  1.0f);
		glTexCoord2f(0.0f, 0.0f); glVertex3f( 1.0f, -1.0f,  1.0f);
		// Left Face
		glTexCoord2f(0.0f, 0.0f); glVertex3f(-1.0f, -1.0f, -1.0f);
		glTexCoord2f(1.0f, 0.0f); glVertex3f(-1.0f, -1.0f,  1.0f);
		glTexCoord2f(1.0f, 1.0f); glVertex3f(-1.0f,  1.0f,  1.0f);
		glTexCoord2f(0.0f, 1.0f); glVertex3f(-1.0f,  1.0f, -1.0f);
	glEnd();

	xrot+=0.3f;
	yrot+=0.2f;
	zrot+=0.4f;
	glFlush();
}

void rotate()
{
	xrot+=0.3f;
	yrot+=0.2f;
	zrot+=0.4f;
	glutPostRedisplay();
}
void mouse(int button,int state,int x,int y)
{ 
	switch(button)
	{
	case GLUT_LEFT_BUTTON:
		if(GLUT_DOWN==state)
		{
			glutIdleFunc(rotate);
		}
		break;
	case GLUT_RIGHT_BUTTON:
		if(GLUT_DOWN==state)
		{
			//glutIdleFunc(0);
		}
		break;
	}
}

int main(int argc, char** argv)
{
	glutInit(&argc, argv);
	glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB | GLUT_DEPTH);
	glutInitWindowSize(640,480);
	glutCreateWindow("纹理绑定");
	glutReshapeFunc(ReSizeGLScene);
	glutDisplayFunc(DrawGLScene);
	glutMouseFunc(mouse);
	InitGL();
	glutMainLoop();
	return 0;
}