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bigneil

Member Since 16 Feb 2005
Offline Last Active Nov 15 2012 10:18 AM

Topics I've Started

Time to write rendering engine from scratch

01 November 2012 - 01:24 PM

I have a new assignment where my boss wants me to write the complete source code for a simple rendering engine that can load and render standard file formats like OBJ (at least one format) but it needs to be written from scratch.

It's been a while since I wrote one from the ground up (15 years or so), in fact it seems hardly anything in graphics is written from scratch these days. The pay is great so I don't have a problem doing it, but am at a loss for an estimate and wanted to get a consensus from those with experience.

How long would you estimate it would take to write an OpenGL program that can load say OBJ files and render models without fancy shaders?

Also, what file format is most straightforward to load and render?

Thanks in advance.

Pixel Correct Shadow Maps (Take 2) With Temporal Reprojection

23 October 2008 - 12:06 PM

It's been a year and the previous thread is retired, but I was wondering if wyrzy and coderchris and those guys had any luck implementing Pixel Correct Shadow Maps using the history buffer (Scherzer,2007)? I'm new to shadow maps but was leaning toward that approach. I'm wondering: A) what do we do about moving objects - don't they smudge the history buffer? B) how exactly do we blend the history buffer in Cg. I have two textures representing the last two depth buffers, but I can't seem to blend them without another pass. C) should we use multiple FBO's or one FBO with multiple color buffers - and if so, (with only one depth buffer available per FBO) do we have to translate (i.e. from -1 to 1 range to 0 to 1 range)? I assume I should use the ping ponging technique? Thanks in advance! Previous thread: http://www.gamedev.net/community/forums/topic.asp?topic_id=466799 Original article: http://www.cg.tuwien.ac.at/research/publications/2007/Scherzer-2007-PCS/ [Edited by - bigneil on October 24, 2008 9:14:56 AM]

How can I Zoom without scaling texture?

16 February 2005 - 08:57 AM

Hello, I have a region that is texture mapped, and when I zoom in, I want the texture to remain fixed, as if the region is a window onto the texture, while zooming in/out is simply making the region bigger or smaller, respsectively. I thought this was as easy as scaling the U,Vs as a function of the camera height (I'm using shader language). This keeps the texture a constant size, but it scrolls as I zoom. By default, when you increase the U,V factor (say from 1.0,1.0 toward 0.0,0.0), the texture zooms toward the point 0,0 (the upper left corner). This has a scrolling effect. The texture stays the same size, but it slides diagononally as I zoom. I can zoom to any point on the main diagonal using the equation: y=-.5x+1.5 where x is the U,V scale factor and y is the new U and V. I can zoom to any point on the main diagonal if I substitute the .5 and 1.5 with say, .2 and 1.2 (to zoom to .2,.2). That is, U,V=fx*x+(1.0+fy) where fx,fy = the point you want to zoom to. However I'm trying to zoom to any point on the texture, and when I try say,( .25,.75) the texture starts out off center. Thanks in advance for any ideas, Neil

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