Is this the correct way of calculating and applying attenuation?
This is my basic diffuse shader with attenuation:
.vert
varying vec3 vertex_light_position;
varying vec3 vertex_light_half_vector;
varying vec4 color;
varying vec3 N;
varying vec3 v;
void main(void)
{
v = vec3(gl_ModelViewMatrix * gl_Vertex);
N = normalize(gl_NormalMatrix * gl_Normal);
color = gl_Color;
vertex_light_position = normalize(gl_LightSource[0].position.xyz);
vertex_light_half_vector = normalize(gl_LightSource[0].halfVector.xyz);
gl_Position = gl_ModelViewProjectionMatrix * gl_Vertex;
}
.frag
varying vec3 vertex_light_position;
varying vec3 vertex_light_half_vector;
varying vec4 color;
varying vec3 N;
varying vec3 v;
void main()
{
float constantAttenuation=1.0;
float linearAttenuation=1.0;
float quadraticAttenuation=0.02;
float dist = length(gl_LightSource[0].position - v);
float att = 1.0/(constantAttenuation + (linearAttenuation * dist) + (quadraticAttenuation * dist * dist));
vec3 L = normalize(gl_LightSource[0].position.xyz - v);
vec3 E = normalize(-v);
vec3 R = normalize(reflect(-L,N));
vec4 diffuse_color = vec4(0.0,1.0,0.0,0.0);
float diffuse_value = max(dot(N,L), 0.0);
if (gl_FrontFacing){
gl_FragColor = color + (((diffuse_color-color) * (diffuse_value))*att);
}else{
gl_FragColor = color;
}
}
