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Client/Server States

Started by jgarcia Aug 13, 2003 at 12:14 AM 0 replies 500+ views

Original Post

Aug 13, 2003 at 12:14 AM

Hi all, I have two related questions. Maybe someone can help me. 1.- I can''t understand the concepts of Client and Server side in OpenGL, because I can''t figure out where is the client and where is the server, because all is in the same application. Besides OpenGL is not developed using Object Oriented methodology. 2.- I''m developing a BSP (Quake 3) Loader using one tutorial. And in this tutorial they are using the function "glDrawArrays" and it''s ok I undertand what it does except in one thing, how it calculate the normals ???. Previously to call it thay call the function "glVertexPointer" and send in the parameters the size, format of the vertex, etc. Inside this format are the calculated normals. But I don''t think that the "glDrawArrays" are using it because I never indicate in which offset of this structure are they. Regards, J.Martin

zander76

Aug 13, 2003 at 12:51 AM

Hello..

1. That is more of a historical thing on pcs anyway.. Still very common in Unix, but basically the idea is that its possible to run accross an network. So the graphics are running on one machine will the processing is being handled on another machine.

GL was designed to be as portable as possible and its much easier to hook to c from different languages then c++. So c is the lowest common dinominator (other then asm) but we won't go there.

2. There is a glNormalPointer command as well, create an array the same as you did for the verticies and thats how it gets the normals.

Remember to enable GL_NORMAL_POINTER as well (or what ever that is).

One more thing. Have a look at glDrawElements instead of glDrawArray. glDrawArray needs a lot more redundent information.

Think of a box its got 8 verticies but when you use drawarray you have to send the verts more then once. Infact if your using triangles then each one will be sent 3 times. So the better solution is to have just the 8 verticies in a list and use an index for defining each face.

Later

[edited by - zander76 on August 13, 2003 1:52:16 AM]

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