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  • Reacting to rectangle on rectangle collisions

    - by mcjohnalds45
    I don't know how to react to collisions between two axis aligned rectangles that have x, y, width and height values (x and y are from the centre of the box) to make them simply not overlap. I figured I'd just make them move away from each other depending on how far they intersect in the opposite direction (left, right, up or down) of where they collided. If I check for collisions only on the x axis or only on the y axis it works fine, but when checking for both collisions crazy stuff happens. This code executes when the first box collides with the second. It's in lua but feel free to answer in anything that isn't to too counter-intuitive. if box1.x < box2.x then box1.x = box1.x + box2.x - box1.x - (box1.width / 2) - (box2.width / 2) end if box1.x > box2.x then box1.x = box1.x - (box1.x - box2.x - (box1.width / 2) - (box2.width / 2)) end if box1.y < box2.y then box1.y = box1.y + box2.y - box1.y - (box1.height / 2) - (box2.height / 2) end if box1.y > box2.y then box1.y = box1.y - (box1.y - box2.y - (box1.height / 2) - (box2.height / 2)) end

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  • Shadowmap first phase and shaders

    - by KaiserJohaan
    I am using OpenGL 3.3 and am tryin to implement shadow mapping using cube maps. I have a framebuffer with a depth attachment and a cube map texture. My question is how to design the shaders for the first pass, when creating the shadowmap. This is my vertex shader: in vec3 position; uniform mat4 lightWVP; void main() { gl_Position = lightWVP * vec4(position, 1.0); } Now, do I even need a fragment shader in this shader pass? from what I understand after reading http://www.opengl.org/wiki/Fragment_Shader, by default gl_FragCoord.z is written to the currently attached depth component (to which my cubemap texture is bound to). Thus I shouldnt even need a fragment shader for this pass and from what I understand, there is no other work to do in the fragment shader other than writing this value. Is this correct?

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  • rotate player based off of joystick

    - by pengume
    Hey everyone I have this game that i am making in android and I have a touch screen joystick that moves the player around based on the joysticks position. I cant figure out how to also get the player to rotate at the same angle of the joystick. so when the joystick is to the left the players bitmap is rotated to the left as well. Maybe someone here has some sample code I could look at here is the joysticks class that I am using. `public class GameControls implements OnTouchListener { public float initx = DroidzActivity.screenWidth - 45; //255; // 320 og 425 public float inity = DroidzActivity.screenHeight - 45;//425; // 480 og 267 public Point _touchingPoint = new Point( DroidzActivity.screenWidth - 45, DroidzActivity.screenHeight - 45); public Point _pointerPosition = new Point(DroidzActivity.screenWidth - 100, DroidzActivity.screenHeight - 100); // ogx 220 ogy 150 private Boolean _dragging = false; private boolean attackMode = false; @Override public boolean onTouch(View v, MotionEvent event) { update(event); return true; } private MotionEvent lastEvent; public boolean ControlDragged; private static double angle; public void update(MotionEvent event) { if (event == null && lastEvent == null) { return; } else if (event == null && lastEvent != null) { event = lastEvent; } else { lastEvent = event; } // drag drop if (event.getAction() == MotionEvent.ACTION_DOWN) { if ((int) event.getX() > 0 && (int) event.getX() < 50 && (int) event.getY() > DroidzActivity.screenHeight - 160 && (int) event.getY() < DroidzActivity.screenHeight - 0) { setAttackMode(true); } else { _dragging = true; } } else if (event.getAction() == MotionEvent.ACTION_UP) { if(isAttackMode()){ setAttackMode(false); } _dragging = false; } if (_dragging) { ControlDragged = true; // get the pos _touchingPoint.x = (int) event.getX(); _touchingPoint.y = (int) event.getY(); // Log.d("GameControls", "x = " + _touchingPoint.x + " y = " //+ _touchingPoint.y); // bound to a box if (_touchingPoint.x < DroidzActivity.screenWidth - 75) { // og 400 _touchingPoint.x = DroidzActivity.screenWidth - 75; } if (_touchingPoint.x > DroidzActivity.screenWidth - 15) {// og 450 _touchingPoint.x = DroidzActivity.screenWidth - 15; } if (_touchingPoint.y < DroidzActivity.screenHeight - 75) {// og 240 _touchingPoint.y = DroidzActivity.screenHeight - 75; } if (_touchingPoint.y > DroidzActivity.screenHeight - 15) {// og 290 _touchingPoint.y = DroidzActivity.screenHeight - 15; } // get the angle setAngle(Math.atan2(_touchingPoint.y - inity, _touchingPoint.x - initx) / (Math.PI / 180)); // Move the ninja in proportion to how far // the joystick is dragged from its center _pointerPosition.y += Math.sin(getAngle() * (Math.PI / 180)) * (_touchingPoint.x / 70); // og 180 70 _pointerPosition.x += Math.cos(getAngle() * (Math.PI / 180)) * (_touchingPoint.x / 70); // make the pointer go thru if (_pointerPosition.x > DroidzActivity.screenWidth) { _pointerPosition.x = 0; } if (_pointerPosition.x < 0) { _pointerPosition.x = DroidzActivity.screenWidth; } if (_pointerPosition.y > DroidzActivity.screenHeight) { _pointerPosition.y = 0; } if (_pointerPosition.y < 0) { _pointerPosition.y = DroidzActivity.screenHeight; } } else if (!_dragging) { ControlDragged = false; // Snap back to center when the joystick is released _touchingPoint.x = (int) initx; _touchingPoint.y = (int) inity; // shaft.alpha = 0; } } public void setAttackMode(boolean attackMode) { this.attackMode = attackMode; } public boolean isAttackMode() { return attackMode; } public void setAngle(double angle) { this.angle = angle; } public static double getAngle() { return angle; } }` I should also note that the player has animations based on when he is moving or attacking.

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  • Alternatives to multiple sprite batches for achieving 2D particle system depth

    - by Ergwun
    In my 2D XNA game, I render all my sprites with a single sprite batch using SpriteSortMode.BackToFront and BlendState.AlphaBlend. I'm adding a particle system based on the App Hub particles sample. Since this uses SpriteSortMode.Deferred and BlendState.Additive, I will need to have two SpriteBatch.Begin / SpriteBatch.End pairs: one for 'regular' sprites, and one for particles. In my top-down shooter, If I want to have explosions appear under planes, but above the ground, then I believe I will have to have three Begin/End pairs, first to draw everything under the explosions, then to draw the explosions, then to draw everything above the explosions. If I want to have particle effects at multiple different depths, then I'm going to need even more Begin/Endpairs. This is all easy to code, but I'm wondering if there is an alternative way to handle this?

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  • 2D camera perspective projection from 3D coordinates -- HOW?

    - by Jack
    I am developing a camera for a 2D game with a top-down view that has depth. It's almost a 3D camera. Basically, every object has a Z even though it is in 2D, and similarly to parallax layers their position, scale and rotation speed vary based on their Z. I guess this would be a perspective projection. But I am having trouble converting the objects' 3D coordinates into the 2D space of the screen so that everything has correct perspective and scale. I never learned matrices though I did dig the topic a bit today. I tried without using matrices thanks to this article but every attempt gave awkward results. I'm using ActionScript 3 and Flash 11+ (Starling), where the screen coordinates work like this: Left-handed coordinates system illustration I can explain further what I did if you want to help me sort out what's wrong, or you can directly tell me how you would do it properly. In case you prefer the former, read on. These are images showing the formulas I used: upload.wikimedia.org/math/1/c/8/1c89722619b756d05adb4ea38ee6f62b.png upload.wikimedia.org/math/d/4/0/d4069770c68cb8f1aa4b5cfc57e81bc3.png (Sorry new users can't post images, but both are from the wikipedia article linked above, section "Perspective projection". That's where you'll find what all variables mean, too) The long formula is greatly simplified because I believe a normal top-down 2D camera has no X/Y/Z rotation values (correct ?). Then it becomes d = a - c. Still, I can't get it to work. Maybe you could explain what numbers I should put in a(xyz), c(xyz), theta(xyz), and particularly, e(xyz) ? I don't quite get how e is different than c in my case. c.z is also an issue to me. If the Z of the camera's target object is 0, should the camera's Z be something like -600 ? ( = focal length of 600) Whatever I do, it's wrong. I only got it to work when I used arbitrary calculations that "looked" right, like most cameras with parallax layers seem to do, but that's fake! ;) If I want objects to travel between Z layers I might as well do it right. :) Thanks a lot for your help!

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  • Moving a Cube from a GUI texture on iOS [on hold]

    - by London2423
    I really hope someone can help me in this since I am working already two days but without any result. What I' am trying to achieve in this instance is to move a GameObject when a GUI Texture is touch on a Iphone. The GameObject to be moved is named Cube. The Cube has a Script named "Left" that supposedly when is "call it " from the GUITexture the Cube should move left. I hope is clear: I want to "activated" the script in the Game Object from the Guitexture. I try to use send message but without any joy as well so I am using GetComponent. This is the script "inside" the GUITexture using Unity and C# //script inside the gameobject cube so it can move left when call it from the GUItexture void Awake() { left = Cube.GetComponent<Left>().enable = true; } void Start() { Cube = GameObject.Find ("Cube"); } void Update () { //loop through all the touches on the screeen for(int i = 0 ; i < Input.touchCount; i++) { //execute this code for current touch (i) on the screen if(this.guiTexture.HitTest(Input.GetTouch(i).position)) { //if current hits our guiTecture, run this code if(Input.GetTouch (i).phase == TouchPhase.Began) //move the cube object Cube.GetComponent<Left> (); } if(Input.GetTouch (i).phase == TouchPhase.Ended) { return; } if(Input.GetTouch(i).phase == TouchPhase.Stationary); //if current finger is stationary run this code { Cube.GetComponent<Left> (); } } } } } This is the script inside the GameObject named "Cube" that is activated from the Gui Texture and when is activated from the GUITexture should allow the cube to move left public class Left : MonoBehaviour { // Use this for initialization void Start () { } // Update is called once per frame void OnMousedown () { transform.position += Vector3.left * Time.deltaTime; } } Before write here I search all documentation, tutorial videos, forums but I still don't understand where is my mistake. May please someone help me Thanks CL

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  • What causes player box/world geometry glitches in old games?

    - by Alexander
    I'm looking to understand and find the terminology for what causes - or allows - players to interfere with geometry in old games. Famously, ID's Quake3 gave birth to a whole community of people breaking the physics by jumping, sliding, getting stuck and launching themselves off points in geometry. Some months ago (though I'd be darned if I can find it again!) I saw a conference held by Bungie's Vic DeLeon and a colleague in which Vic briefly discussed the issues he ran into while attempting to wrap 'collision' objects (please correct my terminology) around environment objects so that players could appear as though they were walking on organic surfaces, while not clipping through them or appear to be walking on air at certain points, due to complexities in the modeling. My aim is to compose a case study essay for University in which I can tackle this issue in games, drawing on early exploits and how techniques have changed to address such exploits and to aid in the gameplay itself. I have 3 current day example of where exploits still exist, however specifically targeting ID Software clearly shows they've massively improved their techniques between Q3 and Q4. So in summary, with your help please, I'd like to gain a slightly better understanding of this issue as a whole (its terminology mainly) so I can use terms and ask the right questions within the right contexts. In practical application, I know what it is, I know how to do it, but I don't have the benefit of level design knowledge yet and its technical widgety knick-knack terms =) Many thanks in advance AJ

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  • Detecting walls or floors in pygame

    - by Serial
    I am trying to make bullets bounce of walls, but I can't figure out how to correctly do the collision detection. What I am currently doing is iterating through all the solid blocks and if the bullet hits the bottom, top or sides, its vector is adjusted accordingly. However, sometimes when I shoot, the bullet doesn't bounce, I think it's when I shoot at a border between two blocks. Here is the update method for my Bullet class: def update(self, dt): if self.can_bounce: #if the bullet hasnt bounced find its vector using the mousclick pos and player pos speed = -10. range = 200 distance = [self.mouse_x - self.player[0], self.mouse_y - self.player[1]] norm = math.sqrt(distance[0] ** 2 + distance[1] ** 2) direction = [distance[0] / norm, distance[1 ] / norm] bullet_vector = [direction[0] * speed, direction[1] * speed] self.dx = bullet_vector[0] self.dy = bullet_vector[1] #check each block for collision for block in self.game.solid_blocks: last = self.rect.copy() if self.rect.colliderect(block): topcheck = self.rect.top < block.rect.bottom and self.rect.top > block.rect.top bottomcheck = self.rect.bottom > block.rect.top and self.rect.bottom < block.rect.bottom rightcheck = self.rect.right > block.rect.left and self.rect.right < block.rect.right leftcheck = self.rect.left < block.rect.right and self.rect.left > block.rect.left each test tests if it hit the top bottom left or right side of the block its colliding with if self.can_bounce: if topcheck: self.rect = last self.dy *= -1 self.can_bounce = False print "top" if bottomcheck: self.rect = last self.dy *= -1 #Bottom check self.can_bounce = False print "bottom" if rightcheck: self.rect = last self.dx *= -1 #right check self.can_bounce = False print "right" if leftcheck: self.rect = last self.dx *= -1 #left check self.can_bounce = False print "left" else: # if it has already bounced and colliding again kill it self.kill() for enemy in self.game.enemies_list: if self.rect.colliderect(enemy): self.kill() #update position self.rect.x -= self.dx self.rect.y -= self.dy This definitely isn't the best way to do it but I can't think of another way. If anyone has done this or can help that would be awesome!

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  • How to transform mesh components?

    - by Lea Hayes
    I am attempting to transform the components of a mesh directly using a 4x4 matrix. This is working for the vertex positions, but it is not working for the normals (and probably not the tangents either). Here is what I have: // Transform vertex positions - Works like a charm! vertices = mesh.vertices; for (int i = 0; i < vertices.Length; ++i) vertices[i] = transform.MultiplyPoint(vertices[i]); // Does not work, lighting is messed up on mesh normals = mesh.normals; for (int i = 0; i < normals.Length; ++i) normals[i] = transform.MultiplyVector(normals[i]); Note: The input matrix converts from local to world space and is needed to combine multiple meshes together.

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  • Any significant performance cost to using BlendState.Premultiplied?

    - by Donutz
    Normally I guess you'd use BlendState.AlphaBlend because normally when you load your textures through the pipeline they're already premultiplied. However, if you're loading textures at runtime from PNGs or some such, you have to loop through the pixels and premultiply them, which can take a long time if you've got a lot of textures to load. So it looks (haven't tried it) like using BlendState.Premultiplied instead of BlendState.AlphaBlend should handle non-premultiplied textures and produce the same visual result, without all the startup costs. I have to wonder if there's a non-obvious cost to doing this, like a huge drop in performance or something. Anyone know?

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  • What sort of leaderboard for my game?

    - by Martin
    I recently published a word game for Windows Phone and I am really happy to have some players. The game is entirely offline and at the end of a game, the player's score is published to a server. I'm collecting the scores to build a leaderboard. Right now, I don't believe that the leaderboard I offer to my users is appropriate. I essentially accumulate the score of all the games of a user for a given day and that becomes their score. So if Player 1 plays 3 games and gets 100, 150 and 200 points, its score for the day is 450 points. I would like to get your ideas and opinion. How do I keep my game challenging and engaging with a good leaderboard? Should I continue accumulating the score for a day? Should I just keep the best score? Thanks!

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  • Ideas for time-keeping in a webbased RPG?

    - by ashy_32bit
    I'm assigned a task of doing the preliminary research stuff for a web-based MMO RPG. Now my buggiest problem here is "web based" vs "MMO RPG". I did some research about time keeping systems and I'm totally confused as how exactly something as real-time as an MMO-RPG can work on some pull-only (unidirectional) platform like HTTP. I know there is also a turn-based alternative to time keeping but can it work in an MMO setting ? EDIT: Take a battle for example, player A (human) wants to attack Player B (also human) in the open. How does it work when when player A issues the "attack" command on player B ? how do I inform player B that he is being attacked ? and then how exactly the battle goes on between the two in an HTTP based communication channel? To my knowledge this is impossible unless you resort to another technology (HTML is 1-way, that is you can just ask server and get response, server can't update you unless being asked to. this is very well-known and simply explained). So I though maybe I can somehow change the whole timekeeping model from real-time to a more non-real-time model (towards a turn based RPG for example) and somehow work around the whole problem of "interactivity". EDIT2: It is not that I don't wanna use any server side technologies. For sure it is not gonna work client-side-only even for the most trivial of the multi-player games, let alone an RPG. So sure there would be a (probably complex) server side component to it (the so called Game Engine I suppose). The problem is not the technology that implements the logic (game mechanics) bits but the communication technology and how it limits the game mechanics abilities (like how real-time or turn based it is gonna be). HTTP is a request-response protocol meaning you get served only if you ask for it (explicitly send a GET or POST request to the server). HTTP server can not inform you if anything of interest happens in the game world unless you refresh the page (as some suggested) or you use some bi-directional tech (totally different animals) like Flash, WebSock, HTML5 etc etc. So maybe the question is: Is it possible to implement a MMORPG using only HTML5/PHP and no periodic page refreshes? if so what would be rules to make it an MMO-RPG? Can't explain it any clearer. Sorry :D

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  • Collision within a poly

    - by G1i1ch
    For an html5 engine I'm making, for speed I'm using a path poly. I'm having trouble trying to find ways to get collision with the walls of the poly. To make it simple I just have a vector for the object and an array of vectors for the poly. I'm using Cartesian vectors and they're 2d. Say poly = [[550,0],[169,523],[-444,323],[-444,-323],[169,-523]], it's just a pentagon I generated. The object that will collide is object, object.pos is it's position and object.vel is it's velocity. They're both 2d vectors too. I've had some success to get it to find a collision, but it's just black box code I ripped from a c++ example. It's very obscure inside and all it does though is return true/false and doesn't return what vertices are collided or collision point, I'd really like to be able to understand this and make my own so I can have more meaningful collision. I'll tackle that later though. Again the question is just how does one find a collision to walls of a poly given you know the poly vertices and the object's position + velocity? If more info is needed please let me know. And if all anyone can do is point me to the right direction that's great.

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  • Rope Colliding with a Rectangle

    - by Colton
    I have my rope, and I have my rectangles. The rope is similar to the implementation found here: http://nehe.gamedev.net/tutorial/rope_physics/17006/ Now, I want to make the rope properly collide with the rectangle such that the rope will not pass through a rectangle, and wrap around the rectangle and all that good stuff. Currently, I have it set so no rope node can pass through a rect (successfully), however, this means a rope segment can still pass through a block. Ex: So the question is, what can I do to fix this? What I have tried: I create a rectangle between two nodes of a rope, calculate rotation between the nodes, and get myself a transformed rectangle. I can successfully detect a collision between rope segments and a (non-transformed) rectangle. Create a new node or pivot point around the corner of the block, and rearrange nodes to point to the corner node. Trouble is determining what corner the rope segment is passing through. And then the current rope setup goes wonky (based on verlet integration, so a sudden change in position causes the rope to wiggle like a seismograph during a magnitude 8 earth quake.) Among other issues that might be solvable, but its turning into a case by case thing, which doesn't seem right. I think the best answer here would just be a link to a tutorial (I simply can't find any, most lead to box2D or farseer, but I want to at least learn how it works before I hide behind an engine).

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  • What makes games responsive to user input?

    - by zaftcoAgeiha
    Many games have been praised for its responsive gameplay, where each user action input correspond to a quick and precise character movement (eg: super meat boy, shank...) What makes those games responsive? and what prevents other games from achieving the same? How much of it is due to the game framework used to queue mouse/keyboard events and render/update the game and how much is attributed to better coding?

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  • Using a permutation table for simplex noise without storing it

    - by J. C. Leitão
    Generating Simplex noise requires a permutation table for randomisation (e.g. see this question or this example). In some applications, we need to persist the state of the permutation table. This can be done by creating the table, e.g. using def permutation_table(seed): table_size = 2**10 # arbitrary for this question l = range(1, table_size + 1) random.seed(seed) # ensures the same shuffle for a given seed random.shuffle(l) return l + l # see shared link why l + l; is a detail and storing it. Can we avoid storing the full table by generating the required elements every time they are required? Specifically, currently I store the table and call it using table[i] (table is a list). Can I avoid storing it by having a function that computes the element i, e.g. get_table_element(seed, i). I'm aware that cryptography already solved this problem using block cyphers, however, I found it too complex to go deep and implement a block cypher. Does anyone knows a simple implementation of a block cypher to this problem?

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  • How can I deal with actor translations and other "noise" in third-party motion capture data?

    - by Charles
    I'm working on a game, and I've run into a problem with motion capture data. My team is using 3DS Max 2011 and trying to put free motion capture files on our models. The problem we're having is it has become extremely hard to find motion capture data that stays in place. We've found some great motion captures of things like walking and jumping but the actors themselves move within the data, so when we attach these animations to our models and bring them into XNA, the models walk forward even when they should technically be standing still (and then there's also the problem of them resetting at the end of the animation). How can we clean up, at runtime or asset-processing time, the animation in these motion capture files?

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  • Implementing a wheeled character controller

    - by Lazlo
    I'm trying to implement Boxycraft's character controller in XNA (with Farseer), as Bryan Dysmas did (minus the jumping part, yet). My current implementation seems to sometimes glitch in between two parallel planes, and fails to climb 45 degree slopes. (YouTube videos in links, plane glitch is subtle). How can I fix it? From the textual description, I seem to be doing it right. Here is my implementation (it seems like a huge wall of text, but it's easy to read. I wish I could simplify and isolate the problem more, but I can't): public Body TorsoBody { get; private set; } public PolygonShape TorsoShape { get; private set; } public Body LegsBody { get; private set; } public Shape LegsShape { get; private set; } public RevoluteJoint Hips { get; private set; } public FixedAngleJoint FixedAngleJoint { get; private set; } public AngleJoint AngleJoint { get; private set; } ... this.TorsoBody = BodyFactory.CreateRectangle(this.World, 1, 1.5f, 1); this.TorsoShape = new PolygonShape(1); this.TorsoShape.SetAsBox(0.5f, 0.75f); this.TorsoBody.CreateFixture(this.TorsoShape); this.TorsoBody.IsStatic = false; this.LegsBody = BodyFactory.CreateCircle(this.World, 0.5f, 1); this.LegsShape = new CircleShape(0.5f, 1); this.LegsBody.CreateFixture(this.LegsShape); this.LegsBody.Position -= 0.75f * Vector2.UnitY; this.LegsBody.IsStatic = false; this.Hips = JointFactory.CreateRevoluteJoint(this.TorsoBody, this.LegsBody, Vector2.Zero); this.Hips.MotorEnabled = true; this.AngleJoint = new AngleJoint(this.TorsoBody, this.LegsBody); this.FixedAngleJoint = new FixedAngleJoint(this.TorsoBody); this.Hips.MaxMotorTorque = float.PositiveInfinity; this.World.AddJoint(this.Hips); this.World.AddJoint(this.AngleJoint); this.World.AddJoint(this.FixedAngleJoint); ... public void Move(float m) // -1, 0, +1 { this.Hips.MotorSpeed = 0.5f * m; }

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  • EaseFunction in LoopEntityModifier

    - by Siddharth
    For my game, I need EaseFunction in LoopEntityModifier. In my game, I am rotating ball over certain object. For giving effect I want to use EaseFunction. I want to rotate ball around an object take around 4 to 5 round that was already rotating but I want add some effect so that it looks good. For this I have to use EaseFunction which suits my needs. But if I put EaseFunction in rotation modifier then each round rotation modifier apply an effect of EaseFunction that I want only one time occur either starting or ending time. So if I can able to provide EaseFunction in LoopEntityModifier then it will good for me or something similar also work for me. At present my code is something similar like this. new LoopEntityModifier(new RotationModifier(...)); I hope someone has some idea on this.

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  • simple collision detection

    - by Rob
    Imagine 2 squares sitting side by side, both level with the ground: http://img19.imageshack.us/img19/8085/sqaures2.jpg A simple way to detect if one is hitting the other is to compare the location of each side. They are touching if ALL of the following are NOT true: The right square's left side is to the right of the left square's right side. The right square's right side is to the left of the left square's left side. The right square's bottom side is above the left square's top side. The right square's top side is below the left square's bottom side. If any of those are true, the squares are not touching. If all of those are false, the squares are touching. But consider a case like this, where one square is at a 45 degree angle: http://img189.imageshack.us/img189/4236/squaresb.jpg Is there an equally simple way to determine if those squares are touching?

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  • CW/CCW Rotation of a Vector

    - by user23132
    Considering that I have a vector A, and after an arbitrary rotation I get vector B. I want to use this rotation operation in others vectors as well, but I'm having problems in doing that. My idea do that is to calculate the perpendicular vector C of the plane AB (by calculating AxB). This vector C is the axis that I'll need to rotate. To discover the angle I used the dot product between A and B, the acos of the dot product will return the lowest angle between A and B, the angle ang. The rotation I need to do is then: -rotate *ang*º around the C axis. The problem is that I dont know if this rotation is a CW or CCW rotation, since the cos of the dot product does not give me information of the sign of the angle. There's a tip discover that in 2D ( A.x * B.y - A.y * B.x) that you can use to discover if the vector A is at left/right of vector B. But I dont know how to do this in 3D space. Can anyone help me?

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  • Managing constant buffers without FX interface

    - by xcrypt
    I am aware that there is a sample on working without FX in the samplebrowser, and I already checked that one. However, some questions arise: In the sample: D3DXMATRIXA16 mWorldViewProj; D3DXMATRIXA16 mWorld; D3DXMATRIXA16 mView; D3DXMATRIXA16 mProj; mWorld = g_World; mView = g_View; mProj = g_Projection; mWorldViewProj = mWorld * mView * mProj; VS_CONSTANT_BUFFER* pConstData; g_pConstantBuffer10->Map( D3D10_MAP_WRITE_DISCARD, NULL, ( void** )&pConstData ); pConstData->mWorldViewProj = mWorldViewProj; pConstData->fTime = fBoundedTime; g_pConstantBuffer10->Unmap(); They are copying their D3DXMATRIX'es to D3DXMATRIXA16. Checked on msdn, these new matrices are 16 byte aligned and optimised for intel pentium 4. So as my first question: 1) Is it necessary to copy matrices to D3DXMATRIXA16 before sending them to the constant buffer? And if no, why don't we just use D3DXMATRIXA16 all the time? I have another question about managing multiple constant buffers within one shader. Suppose that, within your shader, you have multiple constant buffers that need to be updated at different times: cbuffer cbNeverChanges { matrix View; }; cbuffer cbChangeOnResize { matrix Projection; }; cbuffer cbChangesEveryFrame { matrix World; float4 vMeshColor; }; Then how would I set these buffers all at different times? g_pd3dDevice->VSSetConstantBuffers( 0, 1, &g_pConstantBuffer10 ); gives me the possibility to set multiple buffers, but that is within one call. 2) Is that okay even if my constant buffers are updated at different times? And do I suppose I have to make sure the constantbuffers are in the same position in the array as the order they appear in the shader?

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  • (Abstract) Game engine design

    - by lukeluke
    I am writing a simple 2D game (for mobile platforms) for the first time. From an abstract point of view, i have the main player controlled by the human, the enemies, elments that will interact with the main player, other living elements that will be controlled by a simple AI (both enemies and non-enemies). The human player will be totally controlled by the player, the other actors will be controlled by AI. So i have a class CActor and a class CActorLogic to start with. I would define a CActor subclass CHero (the main player controlled with some input device). This class will probably implement some type of listener, in order to capture input events. The other players controlled by the AI will be probably a specific subclass of CActor (a subclass per-type, obviously). This seems to be reasonable. The CActor class should have a reference to a method of CActorLogic, that we will call something like CActorLogic::Advance() or similar. Actors should have a visual representation. I would introduce a CActorRepresentation class, with a method like Render() that will draw the actor (that is, the right frame of the right animation). Where to change the animation? Well, the actor logic method Advance() should take care of checking collisions and other things. I would like to discuss the design of a game engine (actors, entities, objects, messages, input handling, visualization of object states (that is, rendering, sound output and so on)) but not from a low level point of view, but from an high level point of view, like i have described above. My question is: is there any book/on line resource that will help me organize things (using an object oriented approach)? Thanks

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  • Inverse projection: question about w coordinate

    - by fayeWilly
    I have to perform in shader an inverse projection from a u/v of a render target. What I do is: Get NDC as 2*(u,v,depth) - 1 Then world space as tmp = (P*V)^-1 * (NDC,1.0); world space = tmp/tmp.w; This apparently works, but I am confused about the w division there. Why this work? Shouldn't be a multiplication by a w somewhere (as in the "forward" pipeline there is the perpsective division?) Thank you, Faye

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  • JavaScript 3D space ship rotation

    - by user36202
    I am working with a fairly low-level JavaScript 3D API (not Three.js) which uses euler angles for rotation. In most cases, euler angles work quite well for doing things like aligning buildings, operating a hovercraft, or looking around in the first-person. However, in space there is no up or down. I want to control the ship's roll, pitch, and yaw. To do that, some people would use a local coordinate system or a permenant matrix or quaternion or whatever to represent the ship's angle. However, since I am not most people and am using a library that deals exclusively in euler angles, I will be using relative angles to represent how to rotate the ship in space and getting the resulting non-relative euler angles. For you math nerds, that means I need to convert 3 euler angles (with Y being the vertical axis, X representing the pitch, and Z representing a roll which is unaffected by the other angles, left-handed system) into a 3x3 orientation matrix, do something fancy with the matrix, and convert it back into the 3 euler angles. Euler to matrix to euler. Somebody has posted something similar to this on SO (http://stackoverflow.com/questions/1217775/rotating-a-spaceship-model-for-a-space-simulator-game) but he ended up just working with a matrix. This will not do for me. Also, I am using JavaScript, not C++. What I want essentially are the functions do_roll, do_pitch, and do_yaw which only take in and put out euler angles. Many thanks.

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