使用Phong模型的点光源照明

我希望使用Phong照明模式渲染包含一个箱子和点光源的场景。以下是我的计算相关的代码片断：使用Phong模型的点光源照明

R3Rgb Phong(R3Scene *scene, R3Ray *ray, R3Intersection *intersection) 
{ 
    R3Rgb radiance; 
    if(intersection->hit == 0) 
    { 
    radiance = scene->background; 
    return radiance; 
    } 

    ... 
    // obtain ambient term 
    ... // this is zero for my test 

    // obtain emissive term 
    ... // this is also zero for my test 

    // for each light in the scene, obtain calculate the diffuse and specular terms 
    R3Rgb intensity_diffuse(0,0,0,1); 
    R3Rgb intensity_specular(0,0,0,1); 
    for(unsigned int i = 0; i < scene->lights.size(); i++) 
    { 
    R3Light *light = scene->Light(i); 
    R3Rgb light_color = LightIntensity(scene->Light(i), intersection->position); 
    R3Vector light_vector = -LightDirection(scene->Light(i), intersection->position); 

    // check if the light is "behind" the surface normal 
    if(normal.Dot(light_vector)<=0) 
     continue; 

    // calculate diffuse reflection 
    if(!Kd.IsBlack()) 
     intensity_diffuse += Kd*normal.Dot(light_vector)*light_color; 

    if(Ks.IsBlack()) 
     continue; 

    // calculate specular reflection 
    ... // this I believe to be irrelevant for the particular test I'm doing 

    } 

    radiance = intensity_diffuse; 
    return radiance; 
} 

R3Rgb LightIntensity(R3Light *light, R3Point position) 
{ 
    R3Rgb light_intensity; 
    double distance; 
    double denominator; 
    if(light->type != R3_DIRECTIONAL_LIGHT) 
    { 
    distance = (position-light->position).Length(); 
    denominator = light->constant_attenuation + 
         (light->linear_attenuation*distance) + 
         (light->quadratic_attenuation*distance*distance); 
    } 

    switch(light->type) 
    { 
    ... 

    case R3_POINT_LIGHT: 
     light_intensity = light->color/denominator; 
     break; 

    ... 
    } 
    return light_intensity; 
} 

R3Vector LightDirection(R3Light *light, R3Point position) 
{ 
    R3Vector light_direction; 
    switch(light->type) 
    { 
    ... 
    case R3_POINT_LIGHT: 
     light_direction = position - light->position; 
     break; 
    ... 
    } 
    light_direction.Normalize(); 
    return light_direction; 
}

相信误差必须在某处或者LightDirection(...)或LightIntensity(...)功能，因为当我运行使用定向光源，我获得所需的渲染图像我的代码（因此这导致我相信Phong照明方程是正确的）。此外，在Phong（...）中，当我计算intensity_diffuse并在调试时，我将light_color除以10，我得到的结果图像看起来更像我所需要的。我是否正确计算了light_color？

谢谢。

来源

2010-04-02 Myx

什么是错误？ – 2010-04-02 00:57:32

生成的渲染图像比预期的要轻。因此，通过“错误”我的意思是，也许我在计算给定点位置的光强度时犯了错误 – Myx 2010-04-02 00:59:29

我刚刚通过添加'light_intensity = light_intensity /（1. + distance + distance * distance）'来测试实现;'' light_intensity = light-> color/denominator;'LightIntensity（...）'中，它似乎给了我想要的。这是正常的吗？编辑：这并不能给我我想要的东西，但似乎需要进行某种划分.... – Myx 2010-04-02 01:12:06

原来我没有错。我比较结果的“最终图像”未正确计算。

来源

2010-04-06 22:13:59 Myx

使用Phong模型的点光源照明

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