OpenGL 照明小物体？
在处理非常小的颗粒时，我遇到了照明问题。我正在进行基于粒子的流体模拟，并且现在将流体渲染为非常小的多边形球体（我所说的非常小，是指球体的半径约为 0.03 个单位）。我的场景中的灯光没有按照我想要的方式照亮它们，而且我无法让它看起来正确。我正在寻找类似于此图像中粒子上的柔和灯光的东西...... 
但是我的粒子看起来像这样...
查看我的粒子如何具有明亮的白色部分，而绿色粒子只是柔和地点亮，并且没有大的白色热点。我知道原因要么是我的灯光设置，要么只是粒子太小，以至于灯光占据了更大的空间（这可能吗？）。我的照明设置如下......
GLfloat mat_ambient[] = {0.5, 0.5, 0.5, 1.0};
GLfloat mat_specular[] = {1.0, 1.0, 1.0, 1.0};
GLfloat mat_shininess[] = {10.0};
GLfloat light_position[] = {0.0, 0.1, p_z, 1.0};
GLfloat model_ambient[] = {0.5, 0.5, 0.5, 1.0};
glMaterialfv(GL_FRONT, GL_AMBIENT, mat_ambient);
glMaterialfv(GL_FRONT, GL_SPECULAR, mat_specular);
glMaterialfv(GL_FRONT, GL_SHININESS, mat_shininess);
glLightfv(GL_LIGHT0, GL_POSITION, light_position);
glLightModelfv(GL_LIGHT_MODEL_AMBIENT, model_ambient);
glEnable(GL_LIGHTING);
glEnable(GL_LIGHT0);
glEnable(GL_DEPTH_TEST);
glShadeModel(GL_SMOOTH);
glColorMaterial(GL_FRONT_AND_BACK,GL_AMBIENT_AND_DIFFUSE);
glEnable(GL_COLOR_MATERIAL);
I'm having a problem with lighting when dealing with really small particles. I'm doing particle-based fluid simulation and am right now rendering the fluid as really tiny polygonized spheres (by really tiny I'm saying about 0.03 units radius for the spheres). The lighting in my scene isn't lighting them how I want and I can't get it to look right. I'm looking for something similar to the soft lighting on the particles in this image...
However my particles look like this...
See how my particles have bright white sections whereas the green particles are just lit up softly and don't have large white hotspots. I know the reason is either the settings for my light or simply the fact that the particles are so small that the light takes up a larger space (is that possible??). My settings for lighting are as follows...
GLfloat mat_ambient[] = {0.5, 0.5, 0.5, 1.0};
GLfloat mat_specular[] = {1.0, 1.0, 1.0, 1.0};
GLfloat mat_shininess[] = {10.0};
GLfloat light_position[] = {0.0, 0.1, p_z, 1.0};
GLfloat model_ambient[] = {0.5, 0.5, 0.5, 1.0};
glMaterialfv(GL_FRONT, GL_AMBIENT, mat_ambient);
glMaterialfv(GL_FRONT, GL_SPECULAR, mat_specular);
glMaterialfv(GL_FRONT, GL_SHININESS, mat_shininess);
glLightfv(GL_LIGHT0, GL_POSITION, light_position);
glLightModelfv(GL_LIGHT_MODEL_AMBIENT, model_ambient);
glEnable(GL_LIGHTING);
glEnable(GL_LIGHT0);
glEnable(GL_DEPTH_TEST);
glShadeModel(GL_SMOOTH);
glColorMaterial(GL_FRONT_AND_BACK,GL_AMBIENT_AND_DIFFUSE);
glEnable(GL_COLOR_MATERIAL);
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感谢大家的所有建议，但不幸的是没有任何效果。我和我的图形学教授坐下来，我们确定这个问题实际上与粒子的大小以及 OpenGL 将定向光视为距离任何顶点无限远这一事实有关。修复它的正确方法是像这样修改光源的恒定衰减...
现在我的粒子看起来像这样...
这正是我想要的灯光！
Thanks for all the suggestions everyone but unfortunately nothing worked. I sat down with my graphics professor and we determined that this problem was in fact related to the size of the particles and the fact that OpenGL treats directional lights as being infinitely far away from any vertex. The proper way to fix it was modifying the constant attenuation of the light source like this...
Now my particles look like this...
which is exactly the lighting I was after!
颗粒的大小不是问题——你的颜色过度饱和了。
对于每个 RGB 分量，您应该具有
环境光 + 漫反射 + 镜面反射 <= 1.0对于这样的场景，我希望
环境光不超过 0.1 左右，漫反射0.6左右，镜面反射弥补其余部分。The size of the particles isn't an issue - you're over-saturating your colours.
For each RGB component, you should have
ambient + diffuse + specular <= 1.0For a scene like this I'd expect
ambientto be no more than 0.1 or so, diffuse of 0.6 or so, and specular making up the rest.看来您需要调低材质的镜面反射分量，稍微调低环境光，并添加一些漫反射着色 (GL_DIFFUSE)。还要考虑将灯光放置在视口/相机后面。
It looks like you need to turn down the specular component of your material, turn down the ambient a bit, and add some diffuse shading (GL_DIFFUSE). Consider also positioning the light behind the the viewport/camera.