旼컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� 뇝 � � � � � 栢栢栢栢方 栢� � � 栢� 栢� 栢� 栢� 栢栢栢� 栢� 栢栢栢栢� 栢� 栢� � � 栢� 栢� 栢� 栢� 栢� 栢� 栢� 栢� 栢� 栢� � � 栢� 栢� 栢� 栢� 栢� 栢� 栢栢栢栢� 栢� 栢� � � 栢� 栢� 栢� 栢� 栢� 栢� 栢� 栢� 栢� 栢� 栢� � � 栢栢栢栢方 栢栢栢栢� 栢� 栢栢栢� 栢� 栢� 栢方 栢方 � � � � T � R � I � A � D � 뇝 � � 突袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴� �袴袴袴袴袴袴袴� � � PRESENTS � � 훤袴袴袴袴袴袴暠 3D-ROTATIONS in 100% ASSEMBLER 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� Code By : Vulture Total Files : 5 File Type : 3d rotation source Release Date : 10th of September '95 Difficulty : Medium level Filename : VGA-VUL4.ARJ 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� Hello there. This is Vulture typing this little textfile. Yeah, uhm, well, some of you might be confused since Outlaw Triad already released sources covering 3d-rotations (VGA-VUL3). But, that source was coded in pascal with some built-in assember and because a lotta people out there are more interested in pure 100% asm, I thought it might be a good idea to release my own little asm source-code covering 3d. This source was coded in IDEAL mode. I'll assume basic knowledge of vga-coding, assembler and Pascal. 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� Hmm, I am not gonna explain 3d-rotations in detail coz there are already lotsa sources and explanations available. If you have a little experience coding asm, you won't have too much trouble understanding the sourcecode. In this textfile I'm just gonna provide you with the formulas needed to rotate a point. These formulas use sine & cosine values. I will show you how to create a sine-chart in Pascal. Also, when you have rotated a point, you will need some formulas to display the point on the screen. These formulas are also provided. Here they come: To rotate a point, use this: Rotate around x-axis YT = Y * COS(xang) - Z * SIN(xang) / 256 ZT = Y * SIN(xang) + Z * COS(xang) / 256 Y = YT Z = ZT Rotate around y-axis XT = X * COS(yang) - Z * SIN(yang) / 256 ZT = X * SIN(yang) + Z * COS(yang) / 256 X = XT Z = ZT Rotate around z-axis XT = X * COS(zang) - Y * SIN(zang) / 256 YT = X * SIN(zang) + Y * COS(zang) / 256 X = XT Y = YT Well, that's it. To see how you can rotate a point in assembler, examine the source. It should not be that hard to understand. One thing that might be a little confusing is the way the sine and cosine values are calculated. Here's how I did it. I used a simple pascal procedure to calculate my sine values. Here it comes: Procedure CalcSine; Var I,Out: Integer; An: Real; Begin For I := 0 to 255 Do { 256 values } Begin An := I*(2*pi / 256); { 2*pi coz of radians! } Out := Round(Sin(An)*256); Sine[I] := Out; { Save into array } End; End; Notice that this particular procedure saves the values into an array. What you must do is change it so it saves the values to a file instead of an array. The close reader might already have guessed that all values here are integers. All values are multiplied with 256 and then rounded to an integer value. In our rotation formulas you will see a divide by 256. Should make perfect sense, shouldn't it? ;) I mean, 256 perfectly fits into a byte. So we can use some fast asm-code in our rotationsource. (sar=>see the source) So, now you have a few sine-values. But, in the formula you also need cosine-values. And those are not provided in this code, you might say... Wrong! They are there. What you must do is add 64 to the degree to get the cosine. Here's a little example: Suppose you have the degree 195. To get the (co)sine-values out of the array, you would do this (in pascal): SineValue := Sine[(195) Mod 256]; { Sine is the name of the array } CosineValue := Sine[(195+64) Mod 256]; The degree value musn't get larger than 255. That's why we use a 'mod 256' in our code. Take a look at the source to see how this is done in assembler. Ok, when you have rotated the point, you would like to put it on the screen somehow, right? ;-) Well, you could use these formulas to do that: Xoff*X / Z+Zoff = Screen x Yoff*Y / Z+Zoff = Screen y The Xoff & Yoff values are 256. But go and change them. It's fun! The X,Y,Z values are those of the current 3d-point you are busy with. Zoff is the distance to the viewer (howfar the object is away). A large Zoff will produce just a small object (it's futher away) while a small Zoff makes a big object. Zoff should not reach 0 coz then you will get the strangest comments... "divide by zero" ... Weird huh? ;-) But seriously, in the example Zoff is 300 but go change it and see what happens. Best way to learn something is by trial and error. Btw, I assume Screen x and Screen y don't need any explanation. Ok, that's all there is to it. Don't worry if you don't understand any of it now. Just go and study this and other sources floating around and you'll get the hang of it eventually. 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� As always this source is not the best way to do 3d-rotations. It was provided to help you on your way in the art of demo-coding. When you have a little experience coding asm/vga, the source should not be that hard to understand. Go and make some improvements on it. Hint: try to insert a look-up table with all y-line offsets in it. Hmm, but if you are a beginner vga-coder, I suggest you try some simpler things instead. It's hard enough as it is... Goodluck to ya and if ya make something nice with this code, please let me know about it. I'm very interested! Btw, as always I'll take no responsibility if this code should damage your computer, house, cat or sumthing. I've had no problems with it and this code is free so go figure. Be seeing ya... Signed: Vulture / Outlaw Triad 컴컴컴컴컴컴컴컴컴컴컴컴컫컴컴컴컴컴컴컴컴컴컴컴컫컴컴컴컴컴컴컴컴컴컴컴컴컴컴 Outlaw Triad Distros : � Greetz from Outlaw: � Releases sofar: 컴컴컴컴컴컴컴컴컴컴컴컴컵컴컴컴컴컴컴컴컴컴컴컴컵컴컴컴컴컴컴컴컴컴컴컴컴컴컴 � � � The Force � � - DemoLisher � � MESSAGE (dosscroller) � +31 (0)36-5346967 � � - ThunderHawk � � - Ash � � VGA-VUL1 (sources) � - Trooper � � FireHouse � � - Rudeboy � � CHAINDOC (textfile) � +31 (0)58-2661590 � � - Utter Chaos � � - Crusher � � VGA-VUL2 (sources) � � � Blue Nose Prod � � - Critical � � BASICDOC (textfile) � +31 (0)345-619401 � � - Da Frisian Force � � - Tribal � � VGA-VUL3 (sources) � - Nailbomb � � � � VGA-VUL4 (sources) open for more! � & all forgotten! � � � + various bbs-intros 컴컴컴컴컴컴컴컴컴컴컴컴컨컴컴컴컴컴컴컴컴컴컴컴컨컴컴컴컴컴컴컴컴컴컴컴컴컴컴 � (C) 1995 O�U�T�L�A�W T�R�I�A�D � 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴