Jump to content

  • Log In with Google      Sign In   
  • Create Account

FREE SOFTWARE GIVEAWAY

We have 4 x Pro Licences (valued at $59 each) for 2d modular animation software Spriter to give away in this Thursday's GDNet Direct email newsletter.


Read more in this forum topic or make sure you're signed up (from the right-hand sidebar on the homepage) and read Thursday's newsletter to get in the running!


GPU Gems Chapter 8. "Simulating Diffraction"'s understanding


Old topic!
Guest, the last post of this topic is over 60 days old and at this point you may not reply in this topic. If you wish to continue this conversation start a new topic.

  • You cannot reply to this topic
No replies to this topic

#1 sienaiwun   Members   -  Reputation: 128

Like
0Likes
Like

Posted 10 June 2012 - 08:48 AM

Hi:
All.
I do not quite understand diffraction's code in GPU Gems Chapter 8.http://http.develope...ugems_ch08.html.

float3 P = mul(ModelViewMatrix, position).xyz;
float3 L = normalize(lightPosition - P);
float3 V = normalize(eyePosition - P);
float3 H = L + V;
float3 N = mul((float3x3)ModelViewMatrixIT, normal);
float3 T = mul((float3x3)ModelViewMatrixIT, tangent);


//from here on,I do not quite understand the parameter u,w,e c. Can you give me some corresponding concept in the equation
Posted Image.

float u = dot(T, H) * d;
float w = dot(N, H);
float e = r * u / w;
float c = exp(-e * e);
float4 anis = hiliteColor * float4(c.x, c.y, c.z, 1);

if (u < 0) u = -u;

float4 cdiff = float4(0, 0, 0, 1);
for (int n = 1; n < 8; n++)
{
float y = 2 * u / n - 1;
cdiff.xyz += blend3(float3(4 * (y - 0.75), 4 * (y - 0.5),
4 * (y - 0.25)));
}

And also I do not understand the meaning of the for loop.

Edited by sienaiwun, 10 June 2012 - 08:49 AM.


Sponsor:



Old topic!
Guest, the last post of this topic is over 60 days old and at this point you may not reply in this topic. If you wish to continue this conversation start a new topic.



PARTNERS