There is a video with the presentation. It didn't help clear things

http://www.youtube.com/watch?feature=player_embedded&v=btNVfUygvio

I was reading Valve/nVidia presentation on the lessons learned when Valve ported Source game engine to OpenGL...

The driver can do some fancy optimizations inside glMultiDrawElements. For example it can create a new index buffer and issue a single draw call. The worst that can happen is do multiple calls of...

I think the rationale behind glMultiDraw is the following. If someone disagrees please correct me

Imagine that you have a single VAO that contains:
- a big VBO with the geometry of your 3 objects...

And what I am trying to say is that by using one buffer you are not using OpenGL with an optimal way. The sequence you describe has read/write dependency problems because every update to the buffer...

I may have an idea on what is wrong.

The draw calls are not executed the time you send them. In most implementations they are stacked in a command buffer and the driver decides when to send for...

One last question that actually matters. Do you use a single UBO for all the meshes or one per mesh?

One UBO for all meshes looks like this I guess:


for mesh in meshes do
update UBO 0
...

What do you mean by "Now I switched to a constant buffer"? Do you have a single buffer with 625 matrices?

I've done some benches myself on UBOs and I found them slower that glUniform* for these...

From what I remember you don't need to protect the shared resources. The implementation should do that for you. Nevertheless there are other things you should worry about (at least on GLES 3.0) like:...

It a bit difficult to root the performance problem but from what you describe you may have this situation:

1. Render to texture 0
2. Switch to another FBO and readpixels from texture 0

The (2)...

One thing you can do is use instancing for batched lights. This may improve things a bit. One bad thing with this implementation of deferred shading is that you speak allot with the API, also you...

A few ideas that are based 3 things (1) minimize GL calls (2) minimize state switching (3) better caching:

Using UBO will be better especially if you have many uniforms per program. You save the...

It's _probably_ because allot of synchronization stuff happen when you swap buffers. I'm not sure though, maybe someone has a more concrete answer than mine.

You need to inform the shader about the transform feedback varyings _prior_ linking it. In GL 3.x you glTransformFeedbackVaryings and then you link.

I've made some tests with SDL but nothing's conclusive at the moment. When I have a solution I will post it here.

Im using SDL 1.3 to create a window and a rendering context for that window (see this tutorial)

I want to create a second context for texture loading in a separate thread (according to OGL 3.3...

The depth buffer keeps values from 0.0 to 1.0 but not in linear manner but in exponential. This practically means that if you visualize it it will be black in pixels very very close to the camera.
...

According to http://www.opengl.org/wiki/Texture#Mipmap_range we round up.

You write "8x2, 4x1, 2,1" you mean "8x2, 4x1, 2x1"??

What is the condition to stop generating mipmaps? Actually, what is the algorithm that calculates the width and height for every level?
...

First of all sorry for the late update, due to lack of time I've tested it yesterday.

I've tried to specify the textures for every mipmap level using glTexImage2D. I didnt create any mipmaps with...

That seems to be exactly what Godlike is trying to do.

Godlike, you properly removed/commented the glGenerateMipmap call from your code in your manual mipmap loading attempt, right? [/QUOTE]
...

Thanks for the reply but I dont believe that GENERATE_MIPMAP is part of opengl 3.3 core. I forgot to mention that I'm working on 3.3 core.

The general idea is that I have an image and its n precalculated mipmaps in files in disk, what I want is to create an empty texture and manualy copy the mipmaps in this texture.

What I currently...

Im pretty adept with OpenGL. I use VBOs (but no VAOs) almost everywhere and in some simple cases I use old school vertex arrays (eg for quad draw in the screen). I'm trying to port my engine to...

Practically you need: vert positions, triangles, texture coords, vertex weights and the skeleton. You can achieve "soft folds" around joints using vertex weights (If I understand correctly what you...