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WhatEver

Member Since 14 Oct 1999
Offline Last Active Mar 25 2015 08:29 AM

Posts I've Made

In Topic: glBindTexture - what is the technical reason that it is slow?

06 March 2015 - 10:08 AM

Ha, so much has changed since I last wrote an OpenGL program! Thanks for the clarification and insight into the latest generation of graphics acceleration.


In Topic: glBindTexture - what is the technical reason that it is slow?

05 March 2015 - 04:36 PM

Never mind, it just sunk in. It doesn't seem like that would be the reasons for being so slow, but I don't really understand the hardware.

 

What's the bind-less function thing you're talking about?


In Topic: glBindTexture - what is the technical reason that it is slow?

05 March 2015 - 04:32 PM

I'm a little confused. Is glBindTexture still slow, but not for the reason I thought, and it's been replaced by a different function: a bindless function?


In Topic: OpenGL artifacts

23 August 2010 - 04:23 AM

You're getting what looks like z fighting. In your case, turning on back face culling should fix it. If not, look at the model and make sure you don't have double sided polygons. If you do delete the polygons you can't see, or never will see.

In Topic: I need help with understanding Invert vs Transpose

28 December 2008 - 06:48 AM

I guess so. I have never scaled my camera before...but I do remember having problems with lighting when my objects are scaled. My shaders perform lighting in object space, so I have to multiply the lights by the inverse of the object world matrix.

I pretty much get how the invert matrix works then, but what about the transpose matrix? I get it when it has to do with rotations, but other than that, I'm clueless. Here's the source code that creates my textureMat for shadowing (it's the same as the one in the OpenGL SuperBible but with my functions)

S3Dmat16f textureMat;

s3dMatIdentity16f(textureMat);
s3dMatTranslate16f(textureMat, 0.5f, 0.5f, 0.5f);
s3dMatScale16f(textureMat, 0.5f, 0.5f, 0.5f);
s3dMatMultiply16x16f(textureMat, projection, textureMat);
s3dMatMultiply16x16f(textureMat, modelView, textureMat);

s3dMatTranspose16f(textureMat);

glTexGenfv(GL_S, GL_EYE_PLANE, &textureMat[0]);
glTexGenfv(GL_T, GL_EYE_PLANE, &textureMat[4]);
glTexGenfv(GL_R, GL_EYE_PLANE, &textureMat[8]);
glTexGenfv(GL_Q, GL_EYE_PLANE, &textureMat[12]);

I understand that S, T, R, and Q are holding the results of the textureMat. But what exactly is going on? I was under the impression that the textureMat would need to be inverted not transposed so that S, T, R, and Q would be brought into texture space.

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