GLSL - 衰減不起作用

Question

問題：隨着距離的增加，衰減不起作用。

我的漫反射，鏡面反射和環境反射看起來正在工作。我添加了衰減變量的公式，然後將每次漫反射，鏡面反射和環境的衰減倍數。

這裏是地面照明的圖像，該光被定位僅次於立方體：

img http://oi42.tinypic.com/28luzci.jpg

.vert

varying vec3 N; 
varying vec3 v; 
varying vec3 c; 
varying float dist; 

void main(void) 
{ 
vec4 ecPos; 
vec3 aux; 

ecPos = gl_ModelViewMatrix * gl_Vertex; 
aux = vec3(gl_LightSource[0].position-ecPos); 
dist = length(aux); 

c = vec3(gl_Color); 
v = vec3(gl_ModelViewMatrix * gl_Vertex);  
N = normalize(gl_NormalMatrix * gl_Normal); 
gl_Position = gl_ModelViewProjectionMatrix * gl_Vertex; 
} 

.frag

varying vec3 N; 
varying vec3 v; 
varying vec3 c;  
varying float dist; 

void main (void) 
{ 
float att; 

att = 1.0/(gl_LightSource[0].constantAttenuation + 
      gl_LightSource[0].linearAttenuation * dist + 
      gl_LightSource[0].quadraticAttenuation * dist * dist); 

vec3 L = normalize(gl_LightSource[0].position.xyz - v); 
vec3 E = normalize(-v); // we are in Eye Coordinates, so EyePos is (0,0,0) 
vec3 R = normalize(-reflect(L,N));  

float nDotL = max(dot(N,L), 0.0); 
float rDotE = max(dot(R,E),0.0); 
float power = pow(rDotE, gl_FrontMaterial.shininess); 

//calculate Ambient Term: 
vec4 Iamb = gl_FrontLightProduct[0].ambient * att;   

//calculate Diffuse Term: 
vec4 Idiff = gl_FrontLightProduct[0].diffuse * nDotL * att; 
Idiff = clamp(Idiff, 0.0, 1.0);  

// calculate Specular Term: 
vec4 Ispec = gl_FrontLightProduct[0].specular * power * att; 
Ispec = clamp(Ispec, 0.0, 1.0); 

// write Total Color: 
gl_FragColor = Iamb + Idiff + Ispec + c; 
} 

Answer 1

檢查出來，也許它會幫助你

http://www.lighthouse3d.com/tutorials/glsl-tutorial/point-light-per-pixel/

http://www.lighthouse3d.com/tutorials/glsl-tutorial/spot-light-per-pixel/

http://www.sccg.sk/~madaras/rtr/phong_tahak.png