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Created 15 Sep 2018
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318 Articles

Documents about Atari computers like ST, STe, Falcon 030, ....

Optimizing for FastRAM & 68060 CPU

DrWatson's profile picture
Published in 
 · 18 May 2024
Well, so it happend, ct60 arrived to our hands =) Short time after receiving my CT60 I've got some nice c2p source from Evil/DHS by Michael Kalms aka Scout/Appendix where I learned some things about 060 so why not write it here:) Burst mode I was very surprised when I didn't find 'burst mode' bit in CACR register. But this doesn't mean 060 has no burst... 060 operates in burst mode all the time :) And what is this burst mode? If you read my article about 030 timing you know how it works in the 030 cache: every word or long read has its place in data cache (unless the data cache isn't disabled and/or fro...

68030 ST RAM and things around it

DrWatson's profile picture
Published in 
 · 18 May 2024
I tell you the truth - I'm always reading about how slow ST RAM is and that Fast RAM is something unbeatable etc, but I never knew WHY. There is only one Falcon timing document - the one published by Rodolphe Czuba with CT2. But in my eyes, this doc is so short/unclear and SHITTILY translated, there's no way to get the idea for non-hw freaks like me. But one nice day I told myself: "It can't be so hard... other ppl understood that, I can too" :-) So I downloaded both uk and fr version of the mentioned doc and started to read... OK, after some weeks :) I've got that damned idea... I have to say I haven't got any osc...

The perfect realtime shadow algorithm

DrWatson's profile picture
Published in 
 · 1 Mar 2024
Written by: Vector/Vertigo (Brian Cowan) Email: cowan@gold.guate.net Vertigo Web Page: http://demoscene.interstat.net/~vertigo/ irc: #coders #vertcode Revision history: 10/06/97 v0.70Beta - Awesome tips from MidNight, touched up the doc 04/06/97 v0.60Beta - Added the tips section with help from Statix 01/06/97 v0.50Beta - A few typo fixes and a cool tip from Statix 30/05/97 v0.10Beta - Initial version INTRODUCTION Well, for the last 2 months or so I have been laying around the house, forcing my brain to try and come up with the perfect shadow algorithm, an algorithm that works beautifull...

Phong lighting and specular highlights

Theory, practice and explaination of the phong lighting and shading model.

DrWatson's profile picture
Published in 
 · 29 Feb 2024
by TimJ/Vertigo "I am he, as you are he, as you are me, and we are all together" email: tim@legend.co.uk irc: #coders #vertcode revision history: 16/02/97 v1.0 - Initial version INTRODUCTION First off, I hope this doc is of use to some people, and maybe other people will find it interesting. Recently, I've been thinking a lot about phong shading and lighting. There was something that was bugging me. I couldn't quite put my finger on it. It was something I knew to be true, but I had to explain it to myself. It all started when I was chatting to Vector about true phong shading. We'd both recently looked at Voltaire&#...

Reflections on Flat-Shading vs. Texture-Mappig

or I Can Live with Flat-Shaded Polygons

DrWatson's profile picture
Published in 
 · 31 Jan 2024
Just before Christmas, I rented two Sega Saturn games, Virtua Racing and Sega Rally Championship, in order to compare the two. Santa was only going to bring me one, so I had to choose: VR was my favorite in the arcades for a very long time, and I had heard just wonderful things about Rally. So I sat down and played both for few hours each, on separate occasions. I fell in love with Rally, but did not much care for the translation of VR -- it was missing the arcade feel. (though, since Santa also brought me an Arcade Racer steering wheel accessory, I happen to really like VR -- perhaps as much as Rally. The steering wheel makes all the dif...

Tiled Texture Mapping for pow2 Texture Sizes

DrWatson's profile picture
Published in 
 · 31 Jan 2024
by TheGlide/SpinningKids Milan, Italy - June 1 st , 1998 INTRODUCTION I assume here you know the basics of texture mapping, as explained in fatmap and fatmap2 docs by MRI/Doomsday. This doc is about texture mapping using texture maps stored as tiles, namely 8x8 pixels tiles. Storing the maps this way can improve very much cache access. Most of the time we have to traverse the texture through non-horizontal lines, and this causes many cache misses. The worst situation happens when we have to traverse the texture vertically: each texel we access will be on a different row, and this will require, from the processor side, a whole cach...

Gravity: how to realistically simulate jumping and interstellar maneuvers

DrWatson's profile picture
Published in 
 · 31 Jan 2024
The information contained in document will allow you to realistically simulate jumping and interstellar maneuvers. The purpose of this document is to understand the physics of the world we live in, and apply realistic physics to your game. It will not give you optimized routines for your program, that is your job! But if you understand how things work, it will be a heck of a lot easier. Basics There are some key terms I will define to make sure we are talking about the same things: Distance : Total path of travel. Displacement : Difference between original position, and final position Speed : Change in displacement divided by the change i...

Perspective Transforms

DrWatson's profile picture
Published in 
 · 21 Jan 2024
By Andre Yew (andrey@gluttony.ugcs.caltech.edu) This is how I learned perspective transforms --- it was intuitive and understandable to me, so perhaps it'll be to others as well. It does require knowledge of matrix math and homogeneous coordinates. IMO, if you want to write a serious renderer, you need to know both. First, let's look at what we're trying to do: S (screen) | * P (y, z) | /| | / | | / | |/ | * R | / | | / | | / | | E (eye)/ | | W ---------*-----|----*------------- <- d -><-z-> E is the eye, P is the point we're trying to project, and R is its projected position on ...

Lighting Your Texture Maps

DrWatson's profile picture
Published in 
 · 21 Jan 2024
Introduction So, you've got your engine running, you have texture mapping, and some kind of shading in place, it runs fast, its smooth, but you feel somethings missing. You need to shade your texture maps. But you haven't got a clue how to do it! Well, I shall now explain the simple process of adding shading or transparency to your textures, in 256 colour mode. 16*16 Linear Palette The easiest way to make primitive shading is to change your palette. Firstly, you will only be able to have 256 / n shades, where n is the number of colours you will be using. Secondly, the image quality is very poor. But, I'll explain it anywa...

Fast Squareroots

DrWatson's profile picture
Published in 
 · 21 Jan 2024
by Arne Steinarson (arst@ludd.luth.se) BRIEF Integer squareroot approximation which executes in 16-27 cycles through effective bitsearch and 256 byte LUT table. Higher value for 486, lower for Pentium systems. On both CPU:s this means a performance improvement of at least 330% compared to using the FPU. In addition one removes the overhead of converting the integer value to a float and back again. OBSERVATION Note that \sqrt{(2^{16})} = 2^{8} , \sqrt{(2^{10})} = 2^{5} . Interesting, just half the position of the bit. But what if we've got a multibit number such as 2710h (=10000 dec)? TRIAL Go looking for the bit in the highest positio...
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