OpenGL：打开和关闭灯光

Question

我正在编写一个程序，其中有一个“polyman”小家伙在0,-3 跳舞。我已经把他染成白色，现在正试图让一个迪斯科般的场景开始，我创造了一个蓝色和红色的灯光，并试图通过使用计数器和if 和else 语句来交替它们。这都是我的renderscene

float ambientlight[] = {0.0,0.0,1.0,1.0};
float diffuselight[] = {1.0,1.0,1.0,1.0};
float specular[] = {1.0,1.0,1.0,1.0};
float lightpos[] = {0.0,10.0,0.0,1.0};  //light 1
float specref[]={1.0,1.0,1.0,1.0};
float spotdir[]={0.0,-10.0,0.0};

float rectX[6][5], rectY[6][5], rectZ[6][5];

float ambientlight2[] = {1.0,0.0,0.0,1.0};
float diffuselight2[] = {1.0,1.0,1.0,1.0};
float specular2[] = {1.0,1.0,1.0,1.0};
float lightpos2[] = {0.0,10.0,0.0,1.0}; //light 2
float specref2[]={1.0,1.0,1.0,1.0};
float spotdir2[]={0.0,-10.0,0.0};


glColor3f(1.0,1.0,1.0);
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
glViewport(0,0,540,440);
glOrtho(-7.0,7.0,-7.0,7.0,5.0,-5.0);

glEnable(GL_LIGHTING);
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
if (counterForLights % 2 == 0)   //if counter even
{
    glLightfv(GL_LIGHT0, GL_POSITION,lightpos);
    glLightfv(GL_LIGHT0,GL_AMBIENT,ambientlight);
    glLightfv(GL_LIGHT0,GL_DIFFUSE,diffuselight);
    glLightfv(GL_LIGHT0,GL_SPECULAR, specular);
    glLightf(GL_LIGHT0,GL_SPOT_CUTOFF,10.0);  //light 1
    glLightf(GL_LIGHT0,GL_SPOT_EXPONENT,15.0);
    glLightfv(GL_LIGHT0,GL_SPOT_DIRECTION,spotdir);
    glEnable(GL_LIGHT0);
    counterForLights++;
}
else  //if counter odd
    {

        glLightfv(GL_LIGHT1,GL_AMBIENT,ambientlight2);
        glLightfv(GL_LIGHT1,GL_DIFFUSE,diffuselight2);
        glLightfv(GL_LIGHT1,GL_SPECULAR, specular2);
        glLightf(GL_LIGHT1,GL_SPOT_CUTOFF,10.0);
        glLightf(GL_LIGHT1,GL_SPOT_EXPONENT,15.0);  //light2
        glLightfv(GL_LIGHT1,GL_SPOT_DIRECTION,spotdir2);
        glEnable(GL_LIGHT1);
        counterForLights++;
    }

counterForLights 是一个全局变量，等于1。它运行，但从不显示红灯，只显示蓝光。关于我在哪里出错的任何想法？

另外，如果您需要查看我的代码，请告诉我！ :)

Answer 1

else  //if counter odd
{

    glLightfv(GL_LIGHT1,GL_AMBIENT,ambientlight2);
    glLightfv(GL_LIGHT1,GL_DIFFUSE,diffuselight2);
    glLightfv(GL_LIGHT1,GL_SPECULAR, specular2);
    glLightf(GL_LIGHT1,GL_SPOT_CUTOFF,10.0);
    glLightf(GL_LIGHT1,GL_SPOT_EXPONENT,15.0);  //light2
    glLightfv(GL_LIGHT1,GL_SPOT_DIRECTION,spotdir2);
    glEnable(GL_LIGHT1);
    counterForLights++;
}

您似乎没有为 LIGHT1 指定位置。

另外，我将/强烈/建议不要使用 Fixed-Function-Pipeline 在 OpenGL 中进行绘图。 There's lots of tutorials online for transitioning to modern OpenGL.

Answer 2

您正在启用灯光 0，然后启用灯光 1，然后再也不禁用任何一个。所以从第二帧开始，光照应该是恒定的。坚持和更新光 0 可能更聪明，或者加载一次系数，然后在任一条件分支中执行启用和禁用。