NeHe教程Qt实现——lesson12

NeHe 系列教程之十二： 显示列表

英文教程地址：lesson12

本课主要演示了显示列表的使用。代码基于第六课。

显示列表的主要接口：

glGenLists

glNewList

glCallList

具体来看代码中的使用：

namespace {

    ...

    static GLfloat boxcol[5][3]=     // Array For Box Colors
    {
        // Bright:  Red, Orange, Yellow, Green, Blue
        {1.0f,0.0f,0.0f},{1.0f,0.5f,0.0f},{1.0f,1.0f,0.0f},{0.0f,1.0f,0.0f},{0.0f,1.0f,1.0f}
    };

    static GLfloat topcol[5][3]=     // Array For Top Colors
    {
        // Dark:  Red, Orange, Yellow, Green, Blue
        {.5f,0.0f,0.0f},{0.5f,0.25f,0.0f},{0.5f,0.5f,0.0f},{0.0f,0.5f,0.0f},{0.0f,0.5f,0.5f}
    };

    GLfloat LightAmbient[]= { 0.5f, 0.5f, 0.5f, 1.0f };             // Ambient Light Values ( NEW )
    GLfloat LightDiffuse[]= { 1.0f, 1.0f, 1.0f, 1.0f };              // Diffuse Light Values ( NEW )
    GLfloat LightPosition[]= { 0.0f, 0.0f, 2.0f, 1.0f };            // Light Position ( NEW )

    GLvoid BuildLists()             // Build Box Display List
    {
        box=glGenLists(2);          // Building Two Lists
        glNewList(box,GL_COMPILE);       // New Compiled box Display List
        glBegin(GL_QUADS);
            // Front Face
            glTexCoord2f(0.0f, 0.0f); glVertex3f(-1.0f, -1.0f,  1.0f);  // Bottom Left Of The Texture and Quad
            glTexCoord2f(1.0f, 0.0f); glVertex3f( 1.0f, -1.0f,  1.0f);  // Bottom Right Of The Texture and Quad
            glTexCoord2f(1.0f, 1.0f); glVertex3f( 1.0f,  1.0f,  1.0f);  // Top Right Of The Texture and Quad
            glTexCoord2f(0.0f, 1.0f); glVertex3f(-1.0f,  1.0f,  1.0f);  // Top Left Of The Texture and Quad
            // Back Face
            glTexCoord2f(1.0f, 0.0f); glVertex3f(-1.0f, -1.0f, -1.0f);  // Bottom Right Of The Texture and Quad
            glTexCoord2f(1.0f, 1.0f); glVertex3f(-1.0f,  1.0f, -1.0f);  // Top Right Of The Texture and Quad
            glTexCoord2f(0.0f, 1.0f); glVertex3f( 1.0f,  1.0f, -1.0f);  // Top Left Of The Texture and Quad
            glTexCoord2f(0.0f, 0.0f); glVertex3f( 1.0f, -1.0f, -1.0f);  // Bottom Left Of The Texture and Quad
            // Top Face
            glTexCoord2f(0.0f, 1.0f); glVertex3f(-1.0f,  1.0f, -1.0f);  // Top Left Of The Texture and Quad
            glTexCoord2f(0.0f, 0.0f); glVertex3f(-1.0f,  1.0f,  1.0f);  // Bottom Left Of The Texture and Quad
            glTexCoord2f(1.0f, 0.0f); glVertex3f( 1.0f,  1.0f,  1.0f);  // Bottom Right Of The Texture and Quad
            glTexCoord2f(1.0f, 1.0f); glVertex3f( 1.0f,  1.0f, -1.0f);  // Top Right Of The Texture and Quad
            // Bottom Face
            glTexCoord2f(1.0f, 1.0f); glVertex3f(-1.0f, -1.0f, -1.0f);  // Top Right Of The Texture and Quad
            glTexCoord2f(0.0f, 1.0f); glVertex3f( 1.0f, -1.0f, -1.0f);  // Top Left Of The Texture and Quad
            glTexCoord2f(0.0f, 0.0f); glVertex3f( 1.0f, -1.0f,  1.0f);  // Bottom Left Of The Texture and Quad
            glTexCoord2f(1.0f, 0.0f); glVertex3f(-1.0f, -1.0f,  1.0f);  // Bottom Right Of The Texture and Quad
            // Right face
            glTexCoord2f(1.0f, 0.0f); glVertex3f( 1.0f, -1.0f, -1.0f);  // Bottom Right Of The Texture and Quad
            glTexCoord2f(1.0f, 1.0f); glVertex3f( 1.0f,  1.0f, -1.0f);  // Top Right Of The Texture and Quad
            glTexCoord2f(0.0f, 1.0f); glVertex3f( 1.0f,  1.0f,  1.0f);  // Top Left Of The Texture and Quad
            glTexCoord2f(0.0f, 0.0f); glVertex3f( 1.0f, -1.0f,  1.0f);  // Bottom Left Of The Texture and Quad
            // Left Face
            glTexCoord2f(0.0f, 0.0f); glVertex3f(-1.0f, -1.0f, -1.0f);  // Bottom Left Of The Texture and Quad
            glTexCoord2f(1.0f, 0.0f); glVertex3f(-1.0f, -1.0f,  1.0f);  // Bottom Right Of The Texture and Quad
            glTexCoord2f(1.0f, 1.0f); glVertex3f(-1.0f,  1.0f,  1.0f);  // Top Right Of The Texture and Quad
            glTexCoord2f(0.0f, 1.0f); glVertex3f(-1.0f,  1.0f, -1.0f);  // Top Left Of The Texture and Quad
        glEnd();
        glEndList();

        top = box + 1;
        glNewList(top,GL_COMPILE);
        // Top Face
        glTexCoord2f(0.0f, 1.0f); glVertex3f(-1.0f,  1.0f, -1.0f);  // Top Left Of The Texture and Quad
        glTexCoord2f(0.0f, 0.0f); glVertex3f(-1.0f,  1.0f,  1.0f);  // Bottom Left Of The Texture and Quad
        glTexCoord2f(1.0f, 0.0f); glVertex3f( 1.0f,  1.0f,  1.0f);  // Bottom Right Of The Texture and Quad
        glTexCoord2f(1.0f, 1.0f); glVertex3f( 1.0f,  1.0f, -1.0f);  // Top Right Of The Texture and Quad
        glEndList();

    }
}

最后 我们再看在绘制代码中的使用：

void MyGLWidget::paintGL()
{
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);  // Clear The Screen And The Depth Buffer
    glLoadIdentity();       // Reset The Current Modelview Matrix
    glTranslatef(0.0f,0.0f,-5.0f);       // Move Into The Screen 5 Units

    glBindTexture(GL_TEXTURE_2D, texture[0]);       // Select Our Texture

    for (yloop=1;yloop<6;yloop++) {
        for (xloop=0;xloop<yloop;xloop++) {
            glLoadIdentity();
            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);      // Tilt The Cubes Up And Down
            glRotatef(45.0f+yrot,0.0f,1.0f,0.0f);               // Spin Cubes Left And Right
            glColor3fv(boxcol[yloop-1]);                    // Select A Box Color
            glCallList(box);
            glColor3fv(topcol[yloop-1]);                    // Select The Top Color
            glCallList(top);                        // Draw The Top
        }
    }

    xrot += 0.3f;                             // X Axis Rotation
    yrot += 0.2f;                             // Y Axis Rotation
}

运行效果如下图所示：