OPENGL 显示BMP图片+旋转

VS2010/Windows 7/

1. 需包含头文件 stdio.h, glaux.h, glut.h。需要对应的lib，并添加包含路径

2. 窗口显示用glut库的函数

3. bmp图片从本地读取，再用它来生成纹理，首先用auxDIBImageLoad函数将图片数据读到AUX_RGBImageRec结构体当中。

    然后

//生成纹理数据

glTexImage2D(GL_TEXTURE_2D, 0, 3, TextureImage[0]->sizeX, TextureImage[0]->sizeY, 0, GL_RGB, GL_UNSIGNED_BYTE, TextureImage[0]->data);

   然后用线性滤波函数按自己要求缩放显示

//线性滤波

glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);

glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);

4. 图片旋转显示的时候用

glRotatef(-90,0.0f,0.0f,1.0f);

或 

//贴图及映射(glTexCoord2f对应纹理坐标, glVertex2f对应矩形坐标,此处已做旋转处理)

glTexCoord2f(0.0f, 0.0f); glVertex2f(-1.0f, 1.0f);     

glTexCoord2f(0.0f, 1.0f); glVertex2f( 1.0f, 1.0f);    

glTexCoord2f(1.0f, 1.0f); glVertex2f( 1.0f, -1.0f); 

glTexCoord2f(1.0f, 0.0f); glVertex2f(-1.0f, -1.0f);     

前一种是旋转函数，后一种是直接在坐标映射时改坐标

效果:

附代码:

#include "stdafx.h"



#include <stdio.h>

#include <gl/glaux.h>

#include<gl/glut.h>



GLfloat xrot;

GLfloat yrot;

GLfloat zrot;



GLuint texture[1]; //存储一个纹理



//读取bmp文件数据

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;

}



//生成纹理

int LoadGLTextures()

{

    int Status = FALSE;

    AUX_RGBImageRec *TextureImage[1];

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

    if (TextureImage[0] = LoadBMP("C:\\2.bmp"))

    {

        Status = TRUE;

        //注册纹理

        glGenTextures(1, &texture[0]); 

        //绑定纹理名称

        glBindTexture(GL_TEXTURE_2D, texture[0]);

        //生成纹理数据

        glTexImage2D(GL_TEXTURE_2D, 0, 3, TextureImage[0]->sizeX, TextureImage[0]->sizeY, 0, GL_RGB, GL_UNSIGNED_BYTE, TextureImage[0]->data);

        //线性滤波

        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;

}



//调用入口

int InitGL(GLvoid)

{

    if (!LoadGLTextures())

    {

        return false;

    }

    glEnable(GL_TEXTURE_2D);

    //glShadeModel(GL_SMOOTH);

    //设置背景色为黑色

    glClearColor(0.0f, 0.0f, 0.0f, 0.0f);

    return TRUE;

}



//贴图绘制

void DrawGLScene(GLvoid)

{

    //清除屏幕缓存

    glClear(GL_COLOR_BUFFER_BIT);    

    //重置当前的模型观察矩阵

    glLoadIdentity();

    

    /**************************************

    * 旋转函数备用 -90表示顺时针绕Z轴旋转90度

    ***************************************/

    //glRotatef(-90,0.0f,0.0f,1.0f);                

    

    //开始绘制四边形

    glBegin(GL_QUADS);



    //贴图及映射(glTexCoord2f对应纹理坐标, glVertex2f对应矩形坐标,此处已做旋转处理)

    glTexCoord2f(0.0f, 0.0f); glVertex2f(-1.0f, 1.0f);     

    glTexCoord2f(0.0f, 1.0f); glVertex2f( 1.0f, 1.0f);    

    glTexCoord2f(1.0f, 1.0f); glVertex2f( 1.0f, -1.0f); 

    glTexCoord2f(1.0f, 0.0f); glVertex2f(-1.0f, -1.0f);     



    glEnd();

    glFlush();

    //glutSwapBuffers();

}



int main(int argc, char **argv)

{

    //初始化glut运行

    glutInit(&argc,argv);

    glutInitDisplayMode(GLUT_DEPTH|GLUT_SINGLE|GLUT_RGBA);

    glutInitWindowPosition(300,100);

    glutInitWindowSize(450, 600);

    glutCreateWindow("hello");

    

    InitGL();

    glutDisplayFunc(&DrawGLScene);

    glutMainLoop();

    return 0;

}

(完)