Re: Collision detection in 2d games when turning is a thing?
Re: Collision detection in 2d games when turning is a thing? I would personally use target_x-player_x, since if you do the reverse youll get the negative values of what they should be. URL: http://forum.audiogames.net/viewtopic.php?pid=197914#p197914 ___ Audiogames-reflector mailing list Audiogames-reflector@sabahattin-gucukoglu.com https://sabahattin-gucukoglu.com/cgi-bin/mailman/listinfo/audiogames-reflector
Re: Collision detection in 2d games when turning is a thing?
Re: Collision detection in 2d games when turning is a thing? I would personally use target_x-player_x, since if you do the reverse youll get the negative values of what they should be. Also you could totate both the object and the point about 0 0 by the angle of the tested object, so that if the point is within the target object, you can determine with a simple bounds check. URL: http://forum.audiogames.net/viewtopic.php?pid=197914#p197914 ___ Audiogames-reflector mailing list Audiogames-reflector@sabahattin-gucukoglu.com https://sabahattin-gucukoglu.com/cgi-bin/mailman/listinfo/audiogames-reflector
Re: Collision detection in 2d games when turning is a thing?
Re: Collision detection in 2d games when turning is a thing? I would personally use target_x-player_x, since if you do the reverse youll get the negative values of what they should be. Also you could rotate both the object and the point about 0 0 by the angle of the tested object, so that the tested object lies with a 0 angle to the x axis, so that if the point is within the target object, you can determine with a simple bounds check. URL: http://forum.audiogames.net/viewtopic.php?pid=197914#p197914 ___ Audiogames-reflector mailing list Audiogames-reflector@sabahattin-gucukoglu.com https://sabahattin-gucukoglu.com/cgi-bin/mailman/listinfo/audiogames-reflector
Re: Collision detection in 2d games when turning is a thing?
Re: Collision detection in 2d games when turning is a thing? You have gone well beyond what BGT can do for you. Leave for C++, C#, Python, or any other language wherein you can find bindings to either ODE or Box2d. Learn and use those; Box2d is much easier than ODE, but ODE lets you use the collision stuff separate from the physics and you can just ignore Z. Save weeks and possibly even months off your development time. And heres the argument for why, presented as me telling you how this kind of math works.So long as the only things that are turning are spheres, its not so bad. Anything beyond spheres means that youre going to need to do a lot of fiddly coding. Even turning boxes isnt trivial-youll almost certainly want to have 2D transformation matrices at that point. If you stick to turning spheres and non-turning boxes (i.e. your game tiles), you can probably manage it to some extent. That said, sphere-box is not the most trivial thing ever, especially if you allow the difference in size between the objects to go above a certain point. In general, if there is a really big object and an extremely small object, a lot of the naive algorithms youre going to want to use go out the window, so its probably best to avoid that. Another thing that will cause problems is small, quickly moving objects.To tell what tile you are hitting next, you need to add the unit vector pointing in the direction of the players motion times the width of a tile to the players position and check that.Assuming east is 0, positive x is east, positive y is north, and angles are both counterclockwise and in radians, the unit vector pointing in the direction of the players motion is (cos(theta), sin(theta)). Multiplying by the tile width gives (tile_width*cos(theta), tile_width*sin(theta)). Add in the players position: (player_x+tile_width*cos(theta), player_y+tile_width*sin(theta))Wh ich, when converted to integers from floats, should be the indices. If 0, 0 is in the top left and not the bottom left, you will need to subtract from the maximum x and y values or everything will be flipped oddly. Otherwise, you can slightly redefine your coordinate system and go directly to a set of equations like those. If you did not understand a word I just said, then go take a class in trigonometry or otherwise learn about it and then revisit this project: youll really, really need to know trig well to do anything along these lines. I cant give you the explanation of what sin and cos are without a diagram, and I cant communicate that across this forum. This is why I am by necessity being quite terse here. URL: http://forum.audiogames.net/viewtopic.php?pid=197825#p197825 ___ Audiogames-reflector mailing list Audiogames-reflector@sabahattin-gucukoglu.com https://sabahattin-gucukoglu.com/cgi-bin/mailman/listinfo/audiogames-reflector
Re: Collision detection in 2d games when turning is a thing?
Re: Collision detection in 2d games when turning is a thing? You have gone well beyond what BGT can do for you. Leave for C++, C#, Python, or any other language wherein you can find bindings to either ODE or Box2d. Learn and use those; Box2d is much easier than ODE, but ODE lets you use the collision stuff separate from the physics and you can just ignore Z. Save weeks and possibly even months off your development time. And heres the argument for why, presented as me telling you how this kind of math works.So long as the only things that are turning are spheres, its not so bad. Anything beyond spheres means that youre going to need to do a lot of fiddly coding. Even turning boxes isnt trivial-youll almost certainly want to have 2D transformation matrices at that point. If you stick to turning spheres and non-turning boxes (i.e. your game tiles), you can probably manage it to some extent. That said, sphere-box is not the most trivial thing ever, especially if you allow the difference in size between the objects to go above a certain point. In general, if there is a really big object and an extremely small object, a lot of the naive algorithms youre going to want to use go out the window, so its probably best to avoid that. Another thing that will cause problems is small, quickly moving objects.To tell what tile you are hitting next, you need to add the unit vector pointing in the direction of the players motion times the width of a tile to the players position and check that.Assuming east is 0, positive x is east, positive y is north, and angles are both counterclockwise and in radians, the unit vector pointing in the direction of the players motion is (cos(theta), sin(theta)). Multiplying by the tile width gives (tile_width*cos(theta), tile_width*sin(theta)). Add in the players position: (player_x+tile_width*cos(theta), player_y+tile_width*sin(theta))Wh ich, when converted to integers from floats, should be the indices. If 0, 0 is in the top left and not the bottom left, you will need to subtract from the maximum x and y values or everything will be flipped oddly. Otherwise, you can slightly redefine your coordinate system and go directly to a set of equations like those. If you did not understand a word I just said, then go take a class in trigonometry or otherwise learn about it and then revisit this project: youll really, really need to know trig well to do anything along these lines. I cant give you the explanation of what sin and cos are without a diagram, and I cant communicate that across this forum. This is why I am by necessity being quite terse here. If you do understand what sin and cos are, and if the term unit vector has meaning, we might be able to effectively talk about doing this further, but the diagram wall exists right at that point and, if youve not see n them, its near impossible to explain whats actually going on here. URL: http://forum.audiogames.net/viewtopic.php?pid=197825#p197825 ___ Audiogames-reflector mailing list Audiogames-reflector@sabahattin-gucukoglu.com https://sabahattin-gucukoglu.com/cgi-bin/mailman/listinfo/audiogames-reflector
Re: Collision detection in 2d games when turning is a thing?
Re: Collision detection in 2d games when turning is a thing? Hi, thats almost what Ive been trying to do. My player is moving with double precision though, so I have been having a bit of trouble. Heres my player class, it, might help explain things.https://www.dropbox.com/s/ftt153iohif5c … r.bgt?dl=1I have been using the unit vector method to calculate how far the player moves already. I am familiar with trig, Im just unsure how to apply it to what Im trying to do here. As I said in my first post. I know I can get the distance and angle between a player and, something like a wall like this.dX = playerX-targetX dY = player-target atan(dY/dX)Im just, not sure how to apply that knowledge to programing. If that makes any sense.Thanks very much for all the help and suggestions! URL: http://forum.audiogames.net/viewtopic.php?pid=197836#p197836 ___ Audiogames-reflector mailing list Audiogames-reflector@sabahattin-gucukoglu.com https://sabahattin-gucukoglu.com/cgi-bin/mailman/listinfo/audiogames-reflector
Re: Collision detection in 2d games when turning is a thing?
Re: Collision detection in 2d games when turning is a thing? Hi, thats almost what Ive been trying to do. My player is moving with double precision though, so I have been having a bit of trouble. Heres my player class, it, might help explain things.https://www.dropbox.com/s/ftt153iohif5c … r.bgt?dl=1I have been using the unit vector method to calculate how far the player moves already. I am familiar with trig, Im just unsure how to apply it to what Im trying to do here. As I said in my first post. I know I can get the distance and angle between a player and, something like a wall like this.dX = playerX-targetX dY = playerY-targetY atan(dY/dX)Im just, not sure how to apply that knowledge to programing. If that makes any sense.Thanks very much for all the help and suggestions! URL: http://forum.audiogames.net/viewtopic.php?pid=197836#p197836 ___ Audiogames-reflector mailing list Audiogames-reflector@sabahattin-gucukoglu.com https://sabahattin-gucukoglu.com/cgi-bin/mailman/listinfo/audiogames-reflector
Re: Collision detection in 2d games when turning is a thing?
Re: Collision detection in 2d games when turning is a thing? Hi, thats almost what Ive been trying to do. My player is moving with double precision though, so I have been having a bit of trouble. Heres my player class, it, might help explain things.https://www.dropbox.com/s/ftt153iohif5c … r.bgt?dl=1I have been using the unit vector method to calculate how far the player moves already. I am familiar with trig, Im just unsure how to apply it to what Im trying to do here. As I said in my first post. I know I can get the distance and angle between a player and, something like a wall like this.dX = playerX-targetX dY = playerY-targetY atan(dY/dX)Im just, not sure how to apply that knowledge to programming. If that makes any sense.Thanks very much for all the help and suggestions! URL: http://forum.audiogames.net/viewtopic.php?pid=197836#p197836 ___ Audiogames-reflector mailing list Audiogames-reflector@sabahattin-gucukoglu.com https://sabahattin-gucukoglu.com/cgi-bin/mailman/listinfo/audiogames-reflector
Re: Collision detection in 2d games when turning is a thing?
Re: Collision detection in 2d games when turning is a thing? Dranelement, does this mean you already have your guy walking around freely in 2D space? So just wall collision is the issue?Since you already have code to calculate the new X Y position of the player after he takes a step (or moves from a game loop, or whatever), this might help you. Instead of updating the players actual position, lets assume the new X and Y you calculated are stored in 2 temporary variables, tempX and tempY.If your walls are stored in a 2D array of bools (I think I read that up above), round tempX and tempY and use those as the 2 coordinates for the 2D wall array to see if it returns true or false. That should let you know if the position your guy is about to step contains a wall or not. If it does not contain a wall, set his X and Y equal to the tempX and tempY variables and youre done.If a wall does exist in that spot, you have 2 options. Option 1 is that you can just play some collision sou nd and do nothing. Because the players X and Y were never set to anything, the guy simply stops when he hits a wall. One side effect of this is that even if the player hits a wall at a shallow angle, they will stop and stick as if the wall is sticky. There is no automatic sliding along it.Option 2 is to check to see if the player should be sliding along a shallow angle. Youll be doing the same wall check as before, but this time youll test (X, tempY) and then (tempX, Y). One of those 2 directions should return a wall and the other will be open land. If (X, tempY) was open land, do not update the players X coordinate. Only update their Y coordinate to be equal to tempY. This is essentially saying that after hitting the wall, any momentum in the individual directions can still continue to act on the player. The end effect is that a player can glance against a wall and continue moving, even though they technically hit something. Perhaps a sliding sound effect or something could play during this, just to help them know theyve hit something but are not actually stopped.There are pros and cons to each method, and hopefully some of this was helpful. URL: http://forum.audiogames.net/viewtopic.php?pid=197837#p197837 ___ Audiogames-reflector mailing list Audiogames-reflector@sabahattin-gucukoglu.com https://sabahattin-gucukoglu.com/cgi-bin/mailman/listinfo/audiogames-reflector
Re: Collision detection in 2d games when turning is a thing?
Re: Collision detection in 2d games when turning is a thing? Hi, thanks very much, that was very helpful! I have actually tried to do that, however I now sometimes get the problem where even if Im not actually facing a wall, Ill still run into the thing. I think your idea of the sliding thing may help, though, so Ill definitely give it a shot.Thanks! URL: http://forum.audiogames.net/viewtopic.php?pid=197838#p197838 ___ Audiogames-reflector mailing list Audiogames-reflector@sabahattin-gucukoglu.com https://sabahattin-gucukoglu.com/cgi-bin/mailman/listinfo/audiogames-reflector
Re: Collision detection in 2d games when turning is a thing?
Re: Collision detection in 2d games when turning is a thing? Dranelement, I dont think I understand. Why would you only collide with a wall you are facing? URL: http://forum.audiogames.net/viewtopic.php?pid=197840#p197840 ___ Audiogames-reflector mailing list Audiogames-reflector@sabahattin-gucukoglu.com https://sabahattin-gucukoglu.com/cgi-bin/mailman/listinfo/audiogames-reflector
Re: Collision detection in 2d games when turning is a thing?
Re: Collision detection in 2d games when turning is a thing? I, guess I didnt really think of it that way. I should probably add some way for a player to check whats around them. URL: http://forum.audiogames.net/viewtopic.php?pid=197841#p197841 ___ Audiogames-reflector mailing list Audiogames-reflector@sabahattin-gucukoglu.com https://sabahattin-gucukoglu.com/cgi-bin/mailman/listinfo/audiogames-reflector
Re: Collision detection in 2d games when turning is a thing?
Re: Collision detection in 2d games when turning is a thing? Sounds good man.Whenever you feel like posting, Im sure were all happy to read about your progress. URL: http://forum.audiogames.net/viewtopic.php?pid=197842#p197842 ___ Audiogames-reflector mailing list Audiogames-reflector@sabahattin-gucukoglu.com https://sabahattin-gucukoglu.com/cgi-bin/mailman/listinfo/audiogames-reflector
Re: Collision detection in 2d games when turning is a thing?
Re: Collision detection in 2d games when turning is a thing? Thanks again for all the help, guys. Im learning a lot from this, and you have been incredibly helpful. URL: http://forum.audiogames.net/viewtopic.php?pid=197844#p197844 ___ Audiogames-reflector mailing list Audiogames-reflector@sabahattin-gucukoglu.com https://sabahattin-gucukoglu.com/cgi-bin/mailman/listinfo/audiogames-reflector
Re: Collision detection in 2d games when turning is a thing?
Re: Collision detection in 2d games when turning is a thing? Id personally do target_x-player_x, not the other way around because you can do the following.If you need to get the angle between an angle, you can use:angle = atan(sin(target_y-player_y)/cos(target_x-player_x))If you have a point at say 3, 3 and the player is at 1, 1, then you can subtract the players coordinates from the targets coordinates. Similarly, if the player is at 3 3 and the target at 1 1, then the relative difference between the 2 points is -2, -2, therefore you get the angle in the appropriate quadrant.If you do player_x-target_x, if the player is at 1 and the target at 2, you get a relative difference of -1, which is the negative of the correct distance. Similarly if the player is at -1 and the target at -2, -1-(-2) = 1, therefore you have the target appearing in the opposite direction. URL: http://forum.audiogames.net/viewtopic.php?pid=197853#p197853 ___ Audiogames-reflector mailing list Audiogames-reflector@sabahattin-gucukoglu.com https://sabahattin-gucukoglu.com/cgi-bin/mailman/listinfo/audiogames-reflector
Re: Collision detection in 2d games when turning is a thing?
Re: Collision detection in 2d games when turning is a thing? If no one has told you, velocities can also be represented as unit vectors times a magnitude. I am almost certain that you know this. You probably want to use your velocity vector as the place to check, not the vector represented by the players facing direction. If velocities can ever be more than one tile per tick, youll run into teleportation through walls issues; for that reason, you may wish to only keep the unit vector and drop the magnitude. In either case, it will fix your issues with only colliding with walls in front, at least if the player can move in other directions besides forward.Atan2 is the function which you are thinking of: given x and y, it gives you an angle. You will probably never use this for collision detection. The only time the angles matter much is in displaying to the player. Collision detection is normally implemented with rotation matrices, another concept that I spent a very long time unders tanding and which I cannot easily convey here. So long as you use only the tile map and spheres, you can entirely avoid them.But I still say use a library. Doing this well took many people a pretty long time, and I think that if youre trying for this kind of simulation, box2d is probably the best fit. Youll spend some time learning to understand it, and its of course possible you dont know other languages, but it will avoid a lot of debugging and math and stuff while also giving you every feature youd ever need and then some. This advice is assuming that you just want a game. I figure any programmer at the point of considering this kind of thing can probably pick up another language pretty quickly, and if its the kind of game youre going to want to write, its worth it, at least in my opinion. Id suggest at least reading some Box2d tutorials at this point--there are some things about it th at might put you off, namely that you talk about forces and not velocities, but its still worth looking at even if you decide not to. URL: http://forum.audiogames.net/viewtopic.php?pid=197863#p197863 ___ Audiogames-reflector mailing list Audiogames-reflector@sabahattin-gucukoglu.com https://sabahattin-gucukoglu.com/cgi-bin/mailman/listinfo/audiogames-reflector
Collision detection in 2d games when turning is a thing?
Collision detection in 2d games when turning is a thing? Hi, Im wondering what the best way to implement collision detection for walls, pits, and other objects is in games when angles are involved. Ive tried to do some research online, but havent really come up with much. Ive gotten walking and turning to work, and I know how I can figure out the distance an object is away, as well the angle the object is at, in relation to the player. At this point though, Ive just put walls in a 2d array, which makes checking for them break in strange, annoying ways, because sometimes Ill not be facing a wall, but the game still thinks I am. Also. Does anyone know how the arc-tangent function in bgt is supposed to work? Im really confused as to why it doesnt need two peramitors, unless it just assumes that you give it an angle, then just subtracts that angle and PI over 2 from Pi?Sorry again if my questions seem incredibly basic Any suggestions would be greatly appreciated! URL: http://forum.audiogames.net/viewtopic.php?pid=197762#p197762 ___ Audiogames-reflector mailing list Audiogames-reflector@sabahattin-gucukoglu.com https://sabahattin-gucukoglu.com/cgi-bin/mailman/listinfo/audiogames-reflector
Re: Collision detection in 2d games when turning is a thing?
Re: Collision detection in 2d games when turning is a thing? arc tangent is the inverse of tangent: you give it a tangent, and it returns the angle. Youd use this, say, if you have sets of coordinates, but need an angle. theta=arc_tangent(dy/dx) (but be sure to catch when dx is 0!), for example.Anyway, its hard to figure how you have things set up based on the description. Are the walls an array of Rectangles/Boxes/coordinates/something else? What about the bounds of your player?It sounds like you might want line-line intersection. There are several ways to do that and I have no idea which is most efficient for a given situation. We can probably come up with a solution given a better idea of how youre representing walls and the player. URL: http://forum.audiogames.net/viewtopic.php?pid=197772#p197772 ___ Audiogames-reflector mailing list Audiogames-reflector@sabahattin-gucukoglu.com https://sabahattin-gucukoglu.com/cgi-bin/mailman/listinfo/audiogames-reflector
Re: Collision detection in 2d games when turning is a thing?
Re: Collision detection in 2d games when turning is a thing? Hi, oh, I didnt realize you could do that. Lots of the atan functions Ive seen ask for an x and a y so...As for walls and the player, walls are represented by a 2d array of bools, which is my problem, I think. The player is represented with a class containing an x, a y, and an angle, along with other functions for walking, weapons, stuff like that. URL: http://forum.audiogames.net/viewtopic.php?pid=197781#p197781 ___ Audiogames-reflector mailing list Audiogames-reflector@sabahattin-gucukoglu.com https://sabahattin-gucukoglu.com/cgi-bin/mailman/listinfo/audiogames-reflector
Re: Collision detection in 2d games when turning is a thing?
Re: Collision detection in 2d games when turning is a thing? A 2d array of bools should be easy: just figure out what tile youd be hitting next, and do a check for it.The problem is one of resolution. Should I assume that each wall/floor tile is roughly the size of the player? Does the player move with double or int precision?It sounds like youve tried something liketarg_x=this.x+(speed*dt*cosine(this.angle));targ_y=this.y+(speed*dt*sine(this.angle));And [targ_x, targ_y] isnt pointing at the tiles youre expecting? URL: http://forum.audiogames.net/viewtopic.php?pid=197789#p197789 ___ Audiogames-reflector mailing list Audiogames-reflector@sabahattin-gucukoglu.com https://sabahattin-gucukoglu.com/cgi-bin/mailman/listinfo/audiogames-reflector
Re: Collision detection in 2d games when turning is a thing?
Re: Collision detection in 2d games when turning is a thing? @Dranelement, the correct way to handle this requires some knowledge of trigonometry for a simple collision detection system or calculus for a more complex system. In any case look for calculations to handle bounded boxes and bounded spheres and then you can correctly calculate if your vector collides with an object at that coordinate. While you can get away with using arrays etc that really isnt the most efficient or correct way to perform collision detection. URL: http://forum.audiogames.net/viewtopic.php?pid=197793#p197793 ___ Audiogames-reflector mailing list Audiogames-reflector@sabahattin-gucukoglu.com https://sabahattin-gucukoglu.com/cgi-bin/mailman/listinfo/audiogames-reflector
