五彩的箱子（NEHE经典教程MFC下的实现：LESSON12)

不再多说，首先按《基于MFC的OpenGL编程》Part 2 Setting up OpenGL on Windows中的介绍，把所有该做的东西都先做好。 这一课讲的是LIST的使用，LIST是在初始化函数里面生成的，也就是说在渲染之前生成的。生成之后是不可改变的，当然，通过下文，大家应该了解到这个“不可改变”是相对的。纹理的生成、光照、颜色还是可以在调用LIST的时候使用的。LIST虽然在程序运行之初生成，但是并不是完全一层不变的东西。

1.增加变量。topcol和boxcol都存储了3X5组数据，用来表示箱顶和除顶部以外的面得5种颜色。

 GLuint texture[1]; // Storage For 1 Texture
    GLuint    box;                // Storage For The Box Display List
    GLuint    top;                // Storage For The Top Display List
    GLuint    xloop;                // Loop For X Axis
    GLuint    yloop;                // Loop For Y Axis

    GLfloat    xrot;                // Rotates Cube On The X Axis
    GLfloat    yrot;                // Rotates Cube On The Y Axis
    GLfloat boxcol[5][3];
    GLfloat topcol[5][3];

2.纹理的绑定和生成，贴上代码，具体的就不多说了。

AUX_RGBImageRec* CdemoView::LoadBMP(char* Filename)
{
    FILE *File=NULL;                                    // File Handle

    if (!Filename)                                        // Make Sure A Filename Was Given
    {
        return NULL;                                    // If Not Return NULL
    }

    File=fopen(Filename,"r");                            // Check To See If The File Exists

    if (File)                                            // Does The File Exist?
    {
        fclose(File);                                    // Close The Handle
return auxDIBImageLoad(Filename);                // Load The Bitmap And Return A Pointer
    }

    return NULL;                                        // If Load Failed Return NULL
}

int CdemoView::LoadGLTextures(void)
{
    int Status=FALSE;                                    // Status Indicator

    AUX_RGBImageRec *TextureImage[1];                    // Create Storage Space For The Texture

    memset(TextureImage,0,sizeof(void*)*1);               // Set The Pointer To NULL

    // Load The Bitmap, Check For Errors, If Bitmap's Not Found Quit
if (TextureImage[0]=LoadBMP("Data/Cube.bmp"))
    {
        Status=TRUE;                                    // Set The Status To TRUE

        glGenTextures(1, &texture[0]);                    // Create The Texture

        // Typical Texture Generation Using Data From The Bitmap
        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 Texture Exists
    {
        if (TextureImage[0]->data)                            // If Texture Image Exists
        {
            free(TextureImage[0]->data);                    // Free The Texture Image Memory
        }

        free(TextureImage[0]);                                // Free The Image Structure
    }

    return Status;                                        // Return The Status

}

3.List的生成，这部分是比较重要的。关于什么事List，不知道的就自己查查吧，是个很好用的东西。不要忘记把它放到初始化函数里面去，否则程序不会运行。

void CdemoView::BuildLists(void)
{
    box=glGenLists(2);                                    // Generate 2 Different Lists
    glNewList(box,GL_COMPILE);                            // Start With The Box List
        glBegin(GL_QUADS);
            // Bottom Face
            glNormal3f( 0.0f,-1.0f, 0.0f);
            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);
            glTexCoord2f(1.0f, 0.0f); glVertex3f(-1.0f, -1.0f,  1.0f);
            // Front Face
            glNormal3f( 0.0f, 0.0f, 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);
            glTexCoord2f(0.0f, 1.0f); glVertex3f(-1.0f,  1.0f,  1.0f);
            // Back Face
            glNormal3f( 0.0f, 0.0f,-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);
            glTexCoord2f(0.0f, 0.0f); glVertex3f( 1.0f, -1.0f, -1.0f);
            // Right face
            glNormal3f( 1.0f, 0.0f, 0.0f);
            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);
            glTexCoord2f(0.0f, 0.0f); glVertex3f( 1.0f, -1.0f,  1.0f);
            // Left Face
            glNormal3f(-1.0f, 0.0f, 0.0f);
            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);
            glTexCoord2f(0.0f, 1.0f); glVertex3f(-1.0f,  1.0f, -1.0f);
        glEnd();
    glEndList();
    top=box+1;                                            // Storage For "Top" Is "Box" Plus One
    glNewList(top,GL_COMPILE);                            // Now The "Top" Display List
        glBegin(GL_QUADS);
            // Top Face
            glNormal3f( 0.0f, 1.0f, 0.0f);
            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);
            glTexCoord2f(1.0f, 1.0f); glVertex3f( 1.0f,  1.0f, -1.0f);
        glEnd();
    glEndList();

}

4.直接到RenderScene了。注意这个双循环，外面是从1到5，里面依次运行1，2，3，4，5次。

void CdemoView::RenderScene(void)
{
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);    // Clear The Screen And The Depth Buffer

    glBindTexture(GL_TEXTURE_2D, texture[0]);
    for (yloop=1;yloop<6;yloop++)
    {
        for (xloop=0;xloop<yloop;xloop++)
        {
            glLoadIdentity();                            // Reset The View
            glTranslatef(1.4f+(float(xloop)*2.8f)-(float(yloop)*1.4f),((6.0f-float(yloop))*2.4f)-7.0f,-20.0f);
            glRotatef(45.0f-(2.0f*yloop)+xrot,1.0f,0.0f,0.0f);
            glRotatef(45.0f+yrot,0.0f,1.0f,0.0f);
            glColor3fv(boxcol[yloop-1]);
            glCallList(box);
            glColor3fv(topcol[yloop-1]);
            glCallList(top);
        }
    }
}

5.加些用来控制的代码。

void CdemoView::OnKeyDown(UINT nChar, UINT nRepCnt, UINT nFlags)
{
    // TODO: Add your message handler code here and/or call default
switch(nChar)
    {
    case VK_RIGHT:
        yrot +=0.3f;
        break;
    case VK_LEFT:
        yrot -=0.3f;
        break;
    case VK_UP:
        xrot -=0.3f;
        break;
    case VK_DOWN:
        xrot +=0.3f;
        break;
    }
    InvalidateRect(NULL,FALSE);
    CView::OnKeyDown(nChar, nRepCnt, nFlags);
}

6.看看运行的结果吧。