Game Development

Gajet

5:15 PM

@Chorche I still don't know what language you are using to build your game...

Kikaimaru

i like turtles

4

Chorche

java

using LWJGL

Gajet

@tylerrrr07 isn't there any automatic syntax highlighting installed :(

@Chorche weren't you trying to learn C++/C#/JS at some points before?

Chorche

yes

Gajet

then why are you jumping from one to another? try getting near master level in one language and then start a new language

Chorche

5:18 PM

well i was trying everything out

i liked java most

Kikaimaru

well what you are doing now is probably easiest way to draw 3d on your own so you are on right track :)

even though i like xna more :)

Gajet

I've recently found out we do have valarray in C++

what a nice class it is :D

John McDonald

so yeah, Java has a Hashtable class where you can store and retrieve objects using a string value: docs.oracle.com/javase/1.4.2/docs/api/java/util/Hashtable.html

Chorche

5:58 PM

what is wrong with this method?

static public FloatBuffer getMousePosition(int mouseX, int mouseY) {
IntBuffer viewport = BufferUtils.createIntBuffer(16);
FloatBuffer modelview = BufferUtils.createFloatBuffer(16);
FloatBuffer projection = BufferUtils.createFloatBuffer(16);
FloatBuffer winZ = BufferUtils.createFloatBuffer(1);
float winX, winY;
FloatBuffer position = BufferUtils.createFloatBuffer(3);
GL11.glGetFloat( GL11.GL_MODELVIEW_MATRIX, modelview );
GL11.glGetFloat( GL11.GL_PROJECTION_MATRIX, projection );
GL11.glGetInteger( GL11.GL_VIEWPORT, viewport );

it should work

but it returns incorect values

tylerrrr07

@Gajet - Nothing comes with Orchard and I didn't see any add ons to do it. I believe I set up the proper CSS / JS references and sent you an email a while back on how to use it though, didn't I?

Gajet

it didn't highlight anything

it just caused it to keep the formating

@tylerrrr07 just the first result in google search : orchardsh.codeplex.com

tylerrrr07

battery.intellisenseless.com/a-little-bit-update-for-ai

You had a typo in your html

You had "pretyprint" when it should have been "prettyprint"

If you want to install that go right ahead

Chorche

@Gajet what should it highlight, how?

tylerrrr07

I have a feeling I searched on wrong terms as I didn't really know what they were called. This was easy enough for me to setup though. Feel free to use what you want :)

Donny

6:18 PM

Hi all, Im looking for someone who can help me get on the right foot towards making my iOS game a turn based online multiplayer

Sam

@Donny Is your game finished and you want to bolt on multiplayer?

Donny

@Sam my game is currently playable (not finished) need to add some better graphics etc but I won't do so until I got it fully working. I want a online function like drawSomething and words with friends have. Been looking around for days now but don't know where to start so I'm going to need some help

Sam

@Donny why not use GameCenter? It's Apple's official framework, and PERFECT for turn based games.

developer.apple.com/library/ios/#documentation/…

Gajet

@Chorche a piece of C++ code I've posted

@tylerrrr07 I've searched "syntax highlight orchard"

Donny

Yes, of course I've looked on game center, but I can't get it to work and in all honesty game center is not exactly what I want.

Sam

6:22 PM

@Donny Can you elaborate more on what you want, and how GC isn't meeting your needs?

Chorche

@Gajet an you help me with the problem?

Gajet

an?

Chorche

up there

Gajet

no I mean what do you need help with?

Chorche

what is wrong with this method?
static public FloatBuffer getMousePosition(int mouseX, int mouseY) {
IntBuffer viewport = BufferUtils.createIntBuffer(16);
FloatBuffer modelview = BufferUtils.createFloatBuffer(16);
FloatBuffer projection = BufferUtils.createFloatBuffer(16);
FloatBuffer winZ = BufferUtils.createFloatBuffer(1);
float winX, winY;
FloatBuffer position = BufferUtils.createFloatBuffer(3);
GL11.glGetFloat( GL11.GL_MODELVIEW_MATRIX, modelview );
GL11.glGetFloat( GL11.GL_PROJECTION_MATRIX, projection );

Donny

6:24 PM

@sam In the future I want to be able to play against android owners aswel, although I would like to start of using game center but I can't get it to work If you're experienced with implementing game center within apps I would love to talk more :p

Gajet

@Chorche I've got no ideas, what might be wrong

since I've never touched the GL directly

but shouldn't that function return a 3D position?

Sam

@Donny If you're hoping for cross platform then GC definitely won't work. I have built multiplayer games using both independent servers, and GC servers. Happy to answer any questions you might have

@Gajet it returns an XY for mouse pos

Gajet

now I've seen it's returning a 3d position

Chorche

@Gajet it returns it, but the values are incorect

Sam

@Chorche is it supposed to return a 3D point that is under the cursor?

Chorche

6:27 PM

probobly

Sam

@Chorche should the 1st param in glReadPixels be winX?

Donny

Oke sounds good, I'm definitely planning on going cross platformed in the future, but I'm not that experienced yet, do you recommend me to go straight into creating my own server for the game since I plan to use this in the future, or do you recommend me to use GC first to learn from it ?

Gajet

I was thinking about the second param should be mouseY

Sam

@Donny depends. You will have to do all of the work over again with GC. What server side languages do you know?

@Donny Could also look in to a PaaS. They are getting pretty popular, especially for gamedev

@Donny something like parse.com/docs/rest

Gajet

@Chorche now I'm pretty sure it should be GL11.glReadPixels(mouseX, mouseY, 1, 1, GL11.GL_DEPTH_COMPONENT, GL11.GL_FLOAT, winZ);

Donny

6:30 PM

@sam that is the problem, only programming I've done is web development, I build php websites connecting to mySQL, 2 months ago I started on objective-c using tutorials and books Picked it up pretty well I believe since I have a pretty entertaining game atm but Now I'm stuck

Chorche

@Gajet i dont think so

i have to go

Gajet

I'm saying based on opengl.org/sdk/docs/man/xhtml/glReadPixels.xml

Sam

@Donny I would write the server in PHP then, expose a REST API for Android and iOS clients to consume it.

Gajet

@tylerrrr07 it's still not highlighting :(

Donny

Oke

Sam

6:32 PM

@Donny I'm writing a multiplayer server with node.js right now. Really please with it. You might enjoy that as well

Gajet

here is the code :
<pre class="brush: cpp;">{
probabilty [p] = NormalDistribution(getDistance(me,p) - getDistance(myTarget,p));
probabilty [p] *= NormalDistribution(
getDistance(myTarget,p) + getDistance(*myTarget.getTarget(),p)
- getDistance(myTarget, *myTarget.getTarget());
probabilty [p] /= getDistance(me,p);
}</pre>

Donny

@sam oke thanks for all the tips but the truth is I'm gonna need a tutorial or something because I don't know where to start

Gajet

@Donny you don't need to start, with node.js you can jump directly in middle of a project!

Sam

@Donny watch the WWDC videos on GC: developer.apple.com/videos/wwdc/2011

Donny

@gajet @sam oke thanks guys hope I'll get something work because I don't wanna lose to much time on getting this app towards the app store it's a pretty good Idea I believe definitely gonna be success in my own country

Sam

6:35 PM

@Donny cool, come back and see us when you have specific questions

tylerrrr07

@Gajet I had fixed it for you whatever you changed since then change it back

Gajet

@tylerrrr07 I didn't change anything, only the theme

and added some new posts

John McDonald

yeah, you've been post crazy

tylerrrr07

I JUST had it working after you mentioned something - aka I fixed the typo for you, looked at the page, and it was highlighting correctly. In the dashboard it says:

Last modified: 8 minutes ago |
By Gajet

Whatever you did broke it again

Gajet

@JohnMcDonald I didn't post that much

John McDonald

6:41 PM

More than 1 per day so far

Gajet

@tylerrrr07 yeah I've logged in to change <pre class="prettyprint"> to <pre class="brush: cpp"

since I assumed I needed to change class type to load new code

tylerrrr07

load new code?

Gajet

@tylerrrr07 seems prettyprint is now working

I tought you installed "orchardsh"

tylerrrr07

no

I said you could :P

I'm not doing that for you

Gajet

:D

tylerrrr07

6:44 PM

I told you I fixed your typo ;)

pretyprint != prettyprint

Gajet

aha,

now get it

tylerrrr07

Cool. Glad we got it working again :)

Gajet

@JohnMcDonald it seems you arr right, 10 posts in 8 days :p

John McDonald

:)

Gajet

I guess I really needed this thing

John McDonald

6:46 PM

I guess so

Gajet

I guess I won't be posting anything for a week now,

but then I'll start working on it again.

@JohnMcDonald did you find anything useful there?

ChrisF

1

Q: Creating Games for Kids

I am interested in creating some simple games for my 2.5 year old daughter. The problem is time: kids grow very fast, and creating an age appropriate game using traditional tools (lets say C++ and OpenGL) would take too long to produce something of use in a reasonable time. By the time, you have ...

game-development

Would you guys be interested in this?

My thoughts would be that you wouldn't, but it's been flagged so I feel obliged to check.

tylerrrr07

Not likely. It falls under the "Which tools should I use" which falls under "too localized"

ChrisF

Thought so.

tylerrrr07

Thanks for checking :D

John McDonald

6:56 PM

yeah, at it's root it's a tech question, but... I do find it interesting

ChrisF

Well not exactly that, but you get my drift

Gajet

@ChrisF anyway his answer is probably Gamemaker

John McDonald

Or unity

Gajet

@john unity is too much heavy weighted for my taste

John McDonald

It's fast for prototyping, and that's why I'd recommend it

Gajet

6:59 PM

I just don't like my experience with it, that's all.

John McDonald

@Gajet Your most recent post isn't bad, although the super AI you describe reminds me of my first AI attempt. I made a re-imagining of Combat and wanted my AI to get on your ass and do things like fire-ahead. My first revision simply had the AI turn toward you and if you were in a 10-degree cone, it would shoot. You would not believe how hard it was to kill that thing

In the end, I made my first AI the "Hard" AI, and had to add delays and wrong decisions to make the "Normal" and "Easy" AI

Gajet

@JohnMcDonald the current implementation is not really that powerful, you just need to trick it run towards it's hunter

but I'll be on my way to create my hard one.

BRB

CaptainRedmuff

Hi all

i'm looking for some information about tile maps, or rather, what a specific type of tile map is called

kind of like the implementation used in rollercoaster tycoon, or transport tycoon

i've been looking into vector field terrain and height map terrain, but i'm not sure they're suitable for what i'm looking to use

it's been a struggle to find any decent info as most people refer to it as isometric tile maps, but I'm looking to create something in 3d with an axonometric perspective

i'm just trying to find the right terms to search google and stackoverflow for resources to help me decide which path to proceed

any help would be greatly appreciated :)

Chorche

7:14 PM

@Gajet i fugured out what was the problem with my method witch converts screen coordinates to world coordinates

when the all my surface is rotated 90* (top-down view) everything works fine

but when i rotate my surface 45* it the method is not "informed" about the rotation\

and i still get the same top-down view coordinates

how can i solve this problem?

3

:D

lol =D

Wow

it's amusing that the inbox shows messages that are sent to you but then deleted

John McDonald

7:27 PM

hah, I thought you deleted it

Gajet

@Chorche I don't really know

@JohnMcDonald now I'm thinking I've developed a game like combat in TP

though without those fancy graphics.

and it dates to real long time ago

just look at how I named my variables back then:

Dave

im kinda stuck :(

Gajet

VAR
x ,n1, y,n2,gm,gd,k :INTEGER;
a,b,j,h,q,p,tt,p2,r,o,t,c1,s1:INTEGER;
a2,b2,j3,h2,tkh,tt2,w,z,c2,s2:INTEGER;
d1:array[1..2500] of INTEGER;
d2:array[1..2500] of INTEGER;
j2:array[1..2500] of INTEGER;
d3:array[1..2500] of INTEGER;
d4:array[1..2500] of INTEGER;
j4:array[1..2500] of INTEGER;
kh1:array[1..20] of INTEGER;
kh2:array[1..20] of INTEGER;
kh3:array[1..20] of INTEGER;
kh4:array[1..20] of INTEGER;

@Dave as usual ;)

Dave

lol :P

mines a maths issue i think

im trying to work out - how to calculate where a npc would be on a given path if the user logged at any random time

Gajet

you can start by the total time it takes for the NPC to finish walking a path

Dave

7:42 PM

well i need to do a to b and then b to a and then the wait time between

Gajet

so we have totalTime = 2*(dist(a,b)) + waitTime?

TreDubZedd

Calculate the total time to walk from a back (through b) to a

Dave

yes @Gajet

TreDubZedd

loginTime % totalLapTime

(assuming a lap starts at 'a')

Gajet

@TreDubZedd did the rest

Dave

7:44 PM

but when npc goes back to a the process repeats

its an infinite repeat - so i need to use time comparisons right?

Gajet

@Dave we know NPC stated walking at time "T0" and we know player logged in exactly at "T1"

any problem till now?

Dave

right..

Gajet

so we know NPC walked the path exactly floor((T1-T0) / totalTime) times.

is it clear why?

Dave

that doesn't make sense

whats totaltime

Gajet

3 mins ago, by Gajet

so we have totalTime = 2*(dist(a,b)) + waitTime?

Dave

7:47 PM

for arguement sake lets say totalTime = 61 minutes;

TreDubZedd

that's 61 minutes for the NPC to arrive at exactly the point at which he starts?

Dave

yes

60 minute for product to be made ... total walk there n back is 1 minute (2 x 30 seconds)

Gajet

also let's assume T1 - T0 = 1232

TreDubZedd

and no wait time at the start?

Gajet

any problem with that?

Dave

7:48 PM

oh wait hang on

sorry its not 61 minutes

cos i just realised as the npc sets off the factory begins making the next product

so its infact 59:30 i think

or have i got confused ?

Gajet

@Dave hah? why should the factory generate goods? you can count only by the number of times NPC walked from A to B and returned.

TreDubZedd

@Dave Tell us the steps the NPC takes, and how long each takes

Dave

ok hang on let me give u the logic steps

Gajet

@TreDubZedd I think you got this one covered, I'm going to work on my project

TreDubZedd

Ok.

Dave

7:52 PM

factory produces "product" 1 per hour.
if(total_product > 0){ total_product --;}
npc walks to "warehouse" / factory starts making the product again
6 tiles to walk (5 seconds per tile) .. total walk time is 1 minute;
npc arrives back at factory and waits until total_product > 0

thats the repeat cycle

TreDubZedd

ok, so let's assume the NPC starts at A, and will immediately begin walking toward B

Dave

now if user logs in at any random time the npc needs to be seen in the correct place

okay....

TreDubZedd

A -> B = 30 seconds.

How long does he stay at B?

Dave

its instant drop off

so he just goes back then

TreDubZedd

ok, so B -> A = 30 seconds. Total so far = 60 seconds.

Now, how long does he wait again at A before leaving for B?

Dave

7:55 PM

he waits until the factory has made the product again which makes 1 per 60 minutes.

TreDubZedd

of which he spent 30 seconds walking, right?

Dave

no he spent 1 minute to return back at A

A is factory, B is warehouse

TreDubZedd

ah, ok

Dave

A to B is 30 seconds, B to A is 30 seconds

TreDubZedd

so, the first tick, he's at the factory (A), and production has just finished?

Dave

7:57 PM

yeh

TreDubZedd

Ok, so the clock immediately restarts on the 60-minutes, while the NPC makes his cycle to the warehouse (B), right?

Dave

yeh i was thinking of doing "start time > or == 60" update start_time to now(); "

for the factory cycle

TreDubZedd

So, just to be clear, the NPC spends 59 out of 60 minutes at the factory?

Dave

yeh - basically in those 59 minutes hes not visible on the map

TreDubZedd

ok, so here's what you do. When the player enters the world, you determine the number of seconds elapsed since the game started. We'll call that totalElapsedTime.

Dave

8:00 PM

when u say "game started"

do u mean started since log in ? or since the creation of it

TreDubZedd

since the creation of it

Dave

okay

TreDubZedd

Take the remainder after dividing by 60 (the modulo function): secondsIntoCycle = totalElapsedTime % 3600 (all done in seconds)

Dave

% means ?

TreDubZedd

that's the modulo operator.

Dave

8:02 PM

isnt that just division

TreDubZedd

30 % 6 == 0. 31 % 6 == 1

Dave

o_0

TreDubZedd

It's the remainder, after dividing

Dave

ohh

it only returns the remainder :P

TreDubZedd

so 30/6 == 5r0. 31/6 == 5r1.

Dave

8:03 PM

never used it before so had to check :P

ok so we get the remainder after dividing...

that gives the time into the walking ?

TreDubZedd

yes

Assuming by "the walking" you mean the entire 60-minute loop

Dave

uh no =/

TreDubZedd

ok, for your purposes, you're saying that the NPC is only visible for the first 60 seconds of that 3600-second loop, right?

Dave

well u dont see him until the 60 minutes has gone because thats how long it takes for the product to make

wouldnt make sense for him to walk before its made

TreDubZedd

but conceptually, he's still "walking" around the back room, or whatever.

Dave

8:10 PM

yeh

waiting around the for slow factory workers :P

hhh

Which tools would you suggest to do sprites? I am totally new here, used inkscape, gimp, imageMagick -- but now trying to understand what the sprites really are and what is needed to do them.

Dave

imagemagick to put them together

hhh

Is there some de-facto standard for sprites?

some dim-issues, some lossless format -- other things?

Dave

well i use png format

hhh

@Dave lossless format but not sure wheter some better choices source here.

Dave

8:13 PM

dont use gif

is it browser based cos if so png is best choice

hhh

Can I use Inkscape with SVG or GImp with XCF? See layers are quite useful to do changes later...

(then just batch-convert things with ImageMagick to png, not big deal)

William 'MindWorX' Mariager

@JohnMcDonald You think an input delay cause framerates to drop? Sound a bit odd. I was thinking it was causing a drop because animations force us to copy the buffer over continuously because it's "dirty" every frame.

John McDonald

Did the FPS actually drop in that JS window sample?

Dave

wat u using to do FPS ? animation request or set interval

hhh

But to the qs:

1. is there some Dimension requirements for sprites?
2. alpha-channeled?
3. is there any specification for sprites?

William 'MindWorX' Mariager

8:16 PM

@JohnMcDonald Yeah.

Dave

@hhh it depends on how large u want your graphics and if u need transparency

but theres no "rule" to sprites

hhh

@Dave I want scalable so gonna use vector format anyway but it is open how and of which-size etc. Is it sprite if I modify one picture slightly (having layers) save them to files and getting all moving positions?

John McDonald

@WilliamMindWorXMariager I'd have to run it again and take a look

William 'MindWorX' Mariager

@hhh, It really depends entirely on what you're working with. Most of the time it doesn't matter, since it's translated to a raw format for the GPU.

@hhh, But PNG is popular and easy to use, and contains most features you'd need for sprites.

Gajet

we've got a new client here !

yeepee :D

William 'MindWorX' Mariager

8:18 PM

A NEW CLIENT?!

Gajet

@hhh I'm talking about you

:D

William 'MindWorX' Mariager

@John, Did you try out the callback stuff?

I'm going to toy a bit with it now.

hhh

@Gajet Thanks for the welcome :)

Gajet

@WilliamMindWorXMariager I literally meant new client, without any mistake in word usage ;)

@hhh tough you can simply be a server, by answering other's questions.

Dave

so when i get the % back how does that explain where in the cycle it is

hhh

8:22 PM

Sticking to that

4. what kind of borders should sprites have? Any margin between pics?
5. Which colors to avoid in sprites?
6. Is there some open-source tools tailored for sprites-generation?
7. am I good to go with brute-force with Gimp/InkScape/Blender/Imagemagick -combo?

William 'MindWorX' Mariager

@hhh, Why do you think any of those things matter? And what do you mean "sprite-generation".

hhh

(My current idea is to create a character first in Blender and then just take pictures of it in different angles, not sure whether the best way but should do or?)

William 'MindWorX' Mariager

I don't think you should expect a tool to just spit out art for you. :P

Dave

how u display the sprites in your code is how u code it more than the rules how u made the image

John McDonald

@WilliamMindWorXMariager no, I haven't checked that out yet

@WilliamMindWorXMariager Check this though: cell.stat-life.com/Playground/CSSTransitionTest.html

Sam

8:25 PM

@WilliamMindWorXMariager If you are on mac: itunes.apple.com/us/app/spritehelperfree/id421369850?mt=12

John McDonald

CSS Transitions, :)

hhh

Well I think Blender could be quite nice later on, it may take a lot of time to generate a moving character with it, requiring anyway some inkscape/etc -- but it could make Sprite generation easier later.

For me, sprite -generation sounds like it could be generated from good Blender -model...

William 'MindWorX' Mariager

@JohnMcDonald Still not very smooth.

hhh

(Some example here with Sonic, now make it take snapshots in different positions -- you can do thing for 3D or 2D depending on preferences later.)

John McDonald

@WilliamMindWorXMariager In awesomium? :( I didn't have a chance to try it

TreDubZedd

8:28 PM

@Dave Sorry about that--I had to step out for a moment

William 'MindWorX' Mariager

@JohnMcDonald Yeah, in Awesomium. I think it has to do with every animation step forcing us to copy the whole buffer again.

John McDonald

:(

Dave

no prob :)

Chorche

@Gajet can you help me a little?

TreDubZedd

@Dave So your number of seconds from 3600 % x is the number of seconds into that whole 60-minute loop. If that number is between 0 and 59.99999, your NPC will be visible.

Gajet

8:30 PM

I would if I knew the answer

Chorche

GL11.glReadPixels(winX, winY, 1,1, GL11.GL_DEPTH_COMPONENT, GL11.GL_FLOAT, winZ);

Dave

that means hes visible for the entire hour ?

Chorche

this caltuates how far is the object on witch i'm pointing the mouse right?

TreDubZedd

No. That's [0...60) in seconds.

Dave

oh the result is in seconds of course

wouldnt it be 50 to 59.9 ?

59 to 59.9

Chorche

8:33 PM

@Gajet hmm?

Dave

►

TreDubZedd

I'm assuming that the NPC is visible at the start of the loop.

Dave

no - it doesnt make sense for him to be visible at the start =/ cos he has to wait for the product to be made first

TreDubZedd

It all depends on where you want to start the loop.

You could "start" with him 75% of the way between the factory and the warehouse, if you wanted it.

Dave

nah the logical way it starts is the factory builds the product first

because it starts as soon as u construct it

TreDubZedd

8:35 PM

Your loop start does not have to coincide with the game start

What you've actually got going on, if I understand correctly, is that your NPC only shows up after the first loop has completed.

Gajet

@Chorche based on what I saw on the manual, you should put mouseX, and mouseY there

TreDubZedd

Look at it this way. At the start of your loop, your factory starts its process.

Dave

yes which takes 60 minutes

TreDubZedd

In every case (except the first one), the NPC starts walking at that point.

Gajet

but reading your code again it seems you can use winX and winY too

Dave

8:37 PM

yeh he wouldn't walk on the first loop because there wasn't a loop before it

TreDubZedd

So, with the exception of that special case, your NPC is walking for the first minute of the 60-minute loop.

Dave

i can solve that with a simple boolean

Chorche

@Gajet yeah, you're right, i already fixed my mistake, but can i do that stuff for only one model - surface

?

Dave

@TreDubZedd okay yes that makes sense now

Gajet

@Chorche now I couldn't even understand your question

Dave

8:38 PM

so if its between 0 and 59.9 how do you solve where he is in the walking path

Chorche

@Gajet look

lets say my mouse is ponting a plane

Sam

@Gajet Log the params to that method so you can see what you're passing

Gajet

@TreDubZedd I would suggest a different method: `position = getPositionInFirstLoop(T1 - T0 - ((int)((T1 - T0) / totalTime))*totalTime)

@Sam I'm not the one having the problem here.

my only problem is I'm being asked a question I don't know anything about :D

@Chorche ok

Chorche

if i will update the planes z coordinate from 1 to 3, the converted coordinate will also change?

Gajet

converted coordinated?

Chorche

8:42 PM

converted mouse coordinate

Gajet

I think it should

Chorche

ok

Gajet

the first time mouse was pointing at (0,0,-3) but in the second run it's pointing at (0,0,-1)

Chorche

so lets say there is another plane

witch is in front of the first

hhh

MOVED the Sprite discussion here to this q here.

(Some feedback to make it better?)

Chorche

8:44 PM

and i want to get the mouse coordinate, like there were no second plane

Gajet

let's me make it clear, by clicking you are casting a ray towards the scene.

and the return value should be the first collision point.

Chorche

what? :D

Gajet

you know what ray-casting is?

Chorche

nope

Gajet

imagine a line in a 3d world

Chorche

8:45 PM

ok

i will draw it on a paper :d

Gajet

which starts from some specific point and moves endlessly towards some specific direction

that line is called ray!

Chorche

ok

Gajet

now ray casting is a term used to show we are trying to check all intersection points between a ray and every other object in the scene

@Chorche did you understand this last part?

Chorche

wait, i'm translating it to my native language :D

Gajet

:D

it might become pretty ugly, since I've translated those from my own language.

Chorche

8:49 PM

yeah, i think i got that

Gajet

now when you are trying to check what's under the cursor you are simply running a raycast. a very special one.

Chorche

so i need to check only one intercection between a ray and the surface?

Gajet

it's special since you already know what is drawn on even pixel, so you know the exact collision point even before casting the ray

you know there should be an object at pixel (50, 60) which is exactly 10meter away from the camera.

that's what depth buffer is used for

everything clear till now?

Chorche

i think

Gajet

now let's talk about projection,

I guess you know what that means

Chorche

8:54 PM

you could explain

Gajet

projection simply means to render a 3D scene,

Chorche

okay

Gajet

every object in 3D scene has a 3 coordinates, but we are going to draw it on a 2D display,

Chorche

aha

Gajet

so you need to compute where each part of surface is going to be drawn,

it's called projection.

unproject is exactly the reverse algorithm

you know pixel, and the distance and camera position. and you want to determine exact 3D position in scene

BBL

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