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  • Dynamic Dijkstra

    - by Dani
    I need dynamic dijkstra algorithm that can update itself when edge's cost is changed without a full recalculation. Full recalculation is not an option. I've tryed to "brew" my own implemantion with no success. I've also tryed to find on the Internet but found nothing. A link to an article explaining the algorithm or even it's name will be good. Edit: Thanks everyone for answering. I managed to make algorithm of my own that runs in O(V+E) time, if anyone wishes to know the algorithm just say so and I will post it.

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  • Achieving certain rendering styles

    - by milesmeow
    I'm trying to assess the difficulty of creating a rendering style that is more like the game Okami and the Quake mods (as shown on this page...search for 'okami','quake npr'). Here's a better page describing the Quake rendering mod. Can a game engine such as Unity be used and programmed to achieve these kind of rendering styles? I'm doing research and am totally new to this so any insight into this would help tremendously.

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  • building a game for different resoulution phones

    - by Jason
    Hi, I am starting some tests for building a game on the android program. So far everything is working and seems nice. However I do not understand how to make sure my game looks correct on all phones as the all will have slightly different screen ratios (and even very different on some odd phones) What I am doing right now is making a view frustrum ( could also be ortho ) which I set to go from -ratio to +ratio ( as I have seen on many examples) however this causes my test shape to be stretched and sometimes cut off by the edge of the screen. I am tilting my phone to landscape to do my tests ( a bit extreame) but it should still render correctly if I have dome things right. Should I be scaling by some ratio before drawing or something? An example would be greatly apriciated PS I am doing a 2d game

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  • Processing component pools problem - Entity Subsystem

    - by mani3xis
    Architecture description I'm creating (designing) an entity system and I ran into many problems. I'm trying to keep it Data-Oriented and efficient as much as possible. My components are POD structures (array of bytes to be precise) allocated in homogeneous pools. Each pool has a ComponentDescriptor - it just contains component name, field types and field names. Entity is just a pointer to array of components (where address acts like an entity ID). EntityPrototype contains entity name and array of component names. Finally Subsystem (System or Processor) which works on component pools. Actual problem The problem is that some components dependents on others (Model, Sprite, PhysicalBody, Animation depends on Transform component) which makes a lot of problems when it comes to processing them. For example, lets define some entities using [S]prite, [P]hysicalBody and [H]ealth: Tank: Transform, Sprite, PhysicalBody BgTree: Transform, Sprite House: Transform, Sprite, Health and create 4 Tanks, 5 BgTrees and 2 Houses and my pools will look like: TTTTTTTTTTT // Transform pool SSSSSSSSSSS // Sprite pool PPPP // PhysicalBody pool HH // Health component There is no way to process them using indices. I spend 3 days working on it and I still don't have any ideas. In previous designs TransformComponent was bound to the entity - but it wasn't a good idea. Can you give me some advices how to process them? Or maybe I should change the overall design? Maybe I should create pools of entites (pools of component pools) - but I guess it will be a nightmare for CPU caches. Thanks

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  • Opposite Force to Apply to a Collided Rigid Body?

    - by Milo
    I'm working on the physics for my GTA2-like game so I can learn more about game physics. The collision detection and resolution are working great. I'm now just unsure how to compute the force to apply to a body after it collides with a wall. My rigid body looks like this: /our simulation object class RigidBody extends Entity { //linear private Vector2D velocity = new Vector2D(); private Vector2D forces = new Vector2D(); private float mass; private Vector2D v = new Vector2D(); //angular private float angularVelocity; private float torque; private float inertia; //graphical private Vector2D halfSize = new Vector2D(); private Bitmap image; private Matrix mat = new Matrix(); private float[] Vector2Ds = new float[2]; private Vector2D tangent = new Vector2D(); private static Vector2D worldRelVec = new Vector2D(); private static Vector2D relWorldVec = new Vector2D(); private static Vector2D pointVelVec = new Vector2D(); private static Vector2D acceleration = new Vector2D(); public RigidBody() { //set these defaults so we don't get divide by zeros mass = 1.0f; inertia = 1.0f; setLayer(LAYER_OBJECTS); } protected void rectChanged() { if(getWorld() != null) { getWorld().updateDynamic(this); } } //intialize out parameters public void initialize(Vector2D halfSize, float mass, Bitmap bitmap) { //store physical parameters this.halfSize = halfSize; this.mass = mass; image = bitmap; inertia = (1.0f / 20.0f) * (halfSize.x * halfSize.x) * (halfSize.y * halfSize.y) * mass; RectF rect = new RectF(); float scalar = 10.0f; rect.left = (int)-halfSize.x * scalar; rect.top = (int)-halfSize.y * scalar; rect.right = rect.left + (int)(halfSize.x * 2.0f * scalar); rect.bottom = rect.top + (int)(halfSize.y * 2.0f * scalar); setRect(rect); } public void setLocation(Vector2D position, float angle) { getRect().set(position.x,position.y, getWidth(), getHeight(), angle); rectChanged(); } public Vector2D getPosition() { return getRect().getCenter(); } @Override public void update(float timeStep) { doUpdate(timeStep); } public void doUpdate(float timeStep) { //integrate physics //linear acceleration.x = forces.x / mass; acceleration.y = forces.y / mass; velocity.x += (acceleration.x * timeStep); velocity.y += (acceleration.y * timeStep); //velocity = Vector2D.add(velocity, Vector2D.scalarMultiply(acceleration, timeStep)); Vector2D c = getRect().getCenter(); v.x = getRect().getCenter().getX() + (velocity.x * timeStep); v.y = getRect().getCenter().getY() + (velocity.y * timeStep); setCenter(v.x, v.y); forces.x = 0; //clear forces forces.y = 0; //angular float angAcc = torque / inertia; angularVelocity += angAcc * timeStep; setAngle(getAngle() + angularVelocity * timeStep); torque = 0; //clear torque } //take a relative Vector2D and make it a world Vector2D public Vector2D relativeToWorld(Vector2D relative) { mat.reset(); Vector2Ds[0] = relative.x; Vector2Ds[1] = relative.y; mat.postRotate(JMath.radToDeg(getAngle())); mat.mapVectors(Vector2Ds); relWorldVec.x = Vector2Ds[0]; relWorldVec.y = Vector2Ds[1]; return relWorldVec; } //take a world Vector2D and make it a relative Vector2D public Vector2D worldToRelative(Vector2D world) { mat.reset(); Vector2Ds[0] = world.x; Vector2Ds[1] = world.y; mat.postRotate(JMath.radToDeg(-getAngle())); mat.mapVectors(Vector2Ds); worldRelVec.x = Vector2Ds[0]; worldRelVec.y = Vector2Ds[1]; return worldRelVec; } //velocity of a point on body public Vector2D pointVelocity(Vector2D worldOffset) { tangent.x = -worldOffset.y; tangent.y = worldOffset.x; pointVelVec.x = (tangent.x * angularVelocity) + velocity.x; pointVelVec.y = (tangent.y * angularVelocity) + velocity.y; return pointVelVec; } public void applyForce(Vector2D worldForce, Vector2D worldOffset) { //add linear force forces.x += worldForce.x; forces.y += worldForce.y; //add associated torque torque += Vector2D.cross(worldOffset, worldForce); } @Override public void draw( GraphicsContext c) { c.drawRotatedScaledBitmap(image, getPosition().x, getPosition().y, getWidth(), getHeight(), getAngle()); } public Vector2D getVelocity() { return velocity; } public void setVelocity(Vector2D velocity) { this.velocity = velocity; } } The way it is given force is by the applyForce method, this method considers angular torque. I'm just not sure how to come up with the vectors in the case where: RigidBody hits static entity RigidBody hits other RigidBody that may or may not be in motion. Would anyone know a way (without too complex math) that I could figure out the opposite force I need to apply to the car? I know the normal it is colliding with and how deep it collided. My main goal is so that say I hit a building from the side, well the car should not just stay there, it should slowly rotate out of it if I'm more than 45 degrees. Right now when I hit a wall I only change the velocity directly which does not consider angular force. Thanks!

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  • Android Loading Screen: How do I use a stack to load elements?

    - by tom_mai78101
    I have some problems with figuring out what value I should put in the function: int value_needed_to_figure_out = X; ProgressBar.incrementProgressBy(value_needed_to_figure_out); I've been researching about loading screens and how to use them. Some examples I've seen have implemented Thread.sleep() in a Handler.post(new Runnable()) function. To me, I got most of that concept of using the Handler to update the ProgressBar, while pretending to do some heavy crunching work. So, I kept looking. I have read this thread here: How do I load chunks of data from an assest manager during a loading screen? It said that I can try using a stack it needs to load, and adding a size counter as I add elements to the stack. What does it mean? This is the part where I'm totally stumped. If anyone would provide some hints, I'll gladly appreciate it. Thanks in advance.

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  • "has no motion" warnings

    - by Adam R. Grey
    When I reimport my project's Library, I get lots of warnings such as State combat.Ghoul Attack has no motion but I have no idea why. In this specific case, I looked up Ghoul Attack. Here's the state in which it appears, in the only animator controller that includes anything called Ghoul Attack: State: m_ObjectHideFlags: 3 m_PrefabParentObject: {fileID: 0} m_PrefabInternal: {fileID: 0} m_Name: Ghoul Attack m_Speed: 1 m_CycleOffset: 0 m_Motions: - {fileID: 7400000, guid: 0db269712a91fd641b6dd5e0e4c6d507, type: 3} - {fileID: 0} m_ParentStateMachine: {fileID: 110708233} m_Position: {x: 492, y: 132, z: 0} m_IKOnFeet: 1 m_Mirror: 0 m_Tag: I thought perhaps that second one - {fileID: 0} was throwing up the warning incorrectly, so I removed it. There was no effect, I still get warnings about Ghoul Attack. So given that the only state I know of with that name does in fact have motion, what is this warning actually trying to tell me?

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  • How to proceed on the waypoint path?

    - by Alpha Carinae
    I'm using Dijkstra algorithm to find shortest path and I'm drawing this path on the screen. As the character object moves on, path updates itself(shortens as the object approaches the target and gets longer as the object moves away from it.) I tried to visualize my problem. This is the beginning state. 'A' node is the target, path is the blue and the object is the green one. I draw this path, from object to the closest node. In this case my problem occurs. Because 'D' node is more closer to the object than 'C' node, something like this happens: So, how can i decide that the object passed the 'D' node? Path should be look like this: One thing comes to my mind is that I use some distance variables between the two closest nodes in the route path. (In this example these are 'C' and 'D' nodes.) As the object approaches 'C' and moves away from the 'D' node at the same time, this means character passed the 'D'. However, I think there are some standardized and easy ways to solve this. What approach should I take?

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  • How can I resolve collisions at different speeds, depending on the direction?

    - by Raven Dreamer
    I have, for all intents and purposes, a Triangle class that objects in my scene can collide with (In actuality, the right side of a parallelogram). My collision detection and resolution code works fine for the purposes of preventing a gameobject from entering into the space of the Triangle, instead directing the movement along the edge. The trouble is, the maximum speed along the x and y axis is not equivalent in my game, and moving along the Y axis (up or down) should take twice as long as an equivalent distance along the X axis (left or right). Unfortunately, these speeds apply to the collision resolution too, and movement along the blue path above progresses twice as fast. What can I do in my collision resolution to make sure that the speedlimit for Y axis movement is obeyed in the latter case? Collision Resolution for this case below (vecInput and velocity are the position and velocity vectors of the game object): // y = mx+c // solve for y. M = 2, x = input's x coord, c = rightYIntercept lowY = 2*vecInput.x + parag.rightYIntercept ; ... else { // y = mx+c // vecInput.y = 2(x) + RightYIntercept // (vecInput.y - RightYIntercept) / 2 = x; //if velocity.Y (positive) greater than velocity.X (negative) //pushing from bottom, so push right. if(velocity.y > -1*velocity.x) { //change the input vector's x position to match the //y position on the shape's edge. Formula for line: Y = MX+C // M is 2, C is rightYIntercept, y is the input y, solve for X. vecInput = new Vector2((vecInput.y - parag.rightYIntercept)/2, vecInput.y); Debug.Log("adjusted rightwards"); } else { vecInput = new Vector2( vecInput.x, lowY); Debug.Log("adjusted downwards"); } }

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  • 3D Vector "End Point" Calculation for procedural Vector Graphics

    - by FrostFlame64
    Alright, So I need some help with some Vector Math. I've developing some game Engines that have Procedural Fractal Generation for Some Graphics, such as using Lindenmayer Systems for generating Trees and Plants. L-Systems, are drawn by using Turtle Graphics, which is a form of Vector graphics. I first created a system to draw in 2D Graphics, which works perfectly fine. But now I want to make a 3D equivalent, and I’ve run into an issue. For my 2D Version, I created a Method for quickly determining the “End Point” of a Vector-like movement. Given a starting point (X, Y), a direction (between 0 and 360 degrees), and a distance, the end point is calculated by these formulas: newX = startX + distance * Sin((PI * direction) / 180) newY = startY + distance * Cos((PI * direction) / 180) Now I need something Similarly Equivalent for performing this Calculation in 3D, But I haven’t been able to Google anything that could show me how to do this. I'm flexible enough to get whatever required information is needed for this method calculation, in any reasonable form (Vector3, Quaternion, ect). To summarize: Given a starting point/vector position in 3D space (X, Y, Z), a Direction in 3D space (Vector3, Quaternion, ect), and a Distance, I need to find the “End Point” in 3D Space. Thank you for your time and help.

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  • Having to check collisions twice per game tic

    - by user22241
    I have vertically moving elevators (3 solid tiles wide) and static solid tiles. Each are separate entities and therefore have their own respective collision routines (to check for, and resolve, collisions with the main character) I check my vertical collisions after characters vertical movements and then horizontal collisions after horizontal movements. The problem is that I want my platform to kill the player if it squashes him from the top, and also if he's on a moving platform (that is moving up) that squashes him into a solid block. Correct behaviour, player on solid blocks being squashed from above by decending elevator Here is what happens. Gravity pushes character into solid block, solid block collision routine corrects characters position and sits him on the solid block which pushes him into the moving elevator, elevator routine then checks for collision and kills player. This assumes I am checking solid blocks first, then elevator collisions. However, if it's the other way around, this happens.... Incorrect behaviour, player on accending elevator gets pushed into solid blocks above Player is on an elevator moving up, gravity pushes him into the elevator, solid block CD routine detects no collision, no action taken. Elevator CD routine detects character has been pushed into elevator by gravity, corrects this by moving character up and sitting him on the elevator and pushes him into the solid blocks above, however the solid block vertical routine has now already run for this tic, so the game continues and the next solid block collision that is encountered is the horizontal routine. This detects a collision and moves the character out of the collision to the left or right of the block which looks odd to say the least (character should get killed here). The only way I've managed to get this working correctly is by running the solid block CD, then the elevator CD, then the solid block CD again straight after. This is clearly wasteful but I can't figure out how else to do this. Any help would be appreciated.

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  • XNA: Huge Tile Map, long load times

    - by Zach
    Recently I built a tile map generator for a game project. What I am very proud of is that I finally got it to the point where I can have a GIANT 2D map build perfectly on my PC. About 120000pixels by 40000 pixels. I can go larger actually, but I have only 1 draw back. #1 ram, the map currently draws about 320MB of ram and I know the Xbox allows 512MB I think? #2 It takes 20 mins for the map to build then display on the Xbox, on my PC it take less then a few seconds. I need to bring that 20 minutes of generating from 20 mins to how ever little bit I can, and how can a lower the amount of RAM usage while still being able to generate my map. Right now everything is stored in Jagged Arrays, each piece generating in a size of 1280x720 (the mother piece). Up to the amount that I need, every block is exactly 40x40 pixels however the blocks get removed from a List or regenerated in a List depending how close the mother piece is to the player. Saving A LOT of CPU, so at all times its no more then looping through 5184 some blocks. Well at least I'm sure of this. But how can I lower my RAM usage without hurting the size of the map, and how can I lower these INSANE loading times? EDIT: Let me explain my self better. Also I'd like to let everyone know now that I'm inexperienced with many of these things. So here is an example of the arrays I'm using. Here is the overall in a shorter term: int[][] array = new int[30][]; array[0] = new int[] { 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2 }; array[1] = new int[] { 1, 3, 3, 3, 3, 1, 0, 0, 0, 0, 1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2 }; that goes on for around 30 arrays downward. Now for every time it hits a 1, it goes and generates a tile map 1280x720 and it does that exactly the way it does it above. This is how I loop through those arrays: for (int i = 0; i < array.Length; i += 1) { for (int h = 0; h < array[i].Length; h += 1) { } { Now how the tiles are drawn and removed is something like this: public void Draw(SpriteBatch spriteBatch, Vector2 cam) { if (cam.X >= this.Position.X - 1280) { if (cam.X <= this.Position.X + 2560) { if (cam.Y >= this.Position.Y - 720) { if (cam.Y <= this.Position.Y + 1440) { if (visible) { if (once == 0) { once = 1; visible = false; regen(); } } for (int i = Tiles.Count - 1; i >= 0; i--) { Tiles[i].Draw(spriteBatch, cam); } for (int i = unWalkTiles.Count - 1; i >= 0; i--) { unWalkTiles[i].Draw(spriteBatch, cam); } } else { once = 0; for (int i = Tiles.Count - 1; i >= 0; i--) { Tiles.RemoveAt(i); } for (int i = unWalkTiles.Count - 1; i >= 0; i--) { unWalkTiles.RemoveAt(i); } } } else { once = 0; for (int i = Tiles.Count - 1; i >= 0; i--) { Tiles.RemoveAt(i); } for (int i = unWalkTiles.Count - 1; i >= 0; i--) { unWalkTiles.RemoveAt(i); } } } else { once = 0; for (int i = Tiles.Count - 1; i >= 0; i--) { Tiles.RemoveAt(i); } for (int i = unWalkTiles.Count - 1; i >= 0; i--) { unWalkTiles.RemoveAt(i); } } } else { once = 0; for (int i = Tiles.Count - 1; i >= 0; i--) { Tiles.RemoveAt(i); } for (int i = unWalkTiles.Count - 1; i >= 0; i--) { unWalkTiles.RemoveAt(i); } } } } If you guys still need more information just ask in the comments.

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  • Trouble exporting Maya models to Panda3D?

    - by Aerovistae
    Having issues here. I added the Panda3D exporter script thing to Maya. 2 things: When I go to export to a .egg, no .egg is formed. Instead a fileToBeExported_temp.mb appears next to the original fileToBeExported.ma. My models use curving meshes with many subdivisions, easily in the thousands, like on the smoothed tentacles of an octopus. Will Panda be able to handle this in the first place? I can't find out on my own since it won't export.

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  • Dynamic audio score/music

    - by Joel Martinez
    I'm interested in developing a game who's background music changes with the mood and scenario of the game's action. Of course many existing games do this (halo for example), but I was interested in any resources/papers/articles talking about the techniques to develop a system like this. I have some ideas, and I understand that this will be equally challenging to implement at the code level as it will be to come up or acquire music that fits this model. Any links or, answers with ideas in them would he appreciated. Edit: this is the kind of info I'm looking for :) http://halo.bungie.org/misc/gdc.2002.music/

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  • What exactly can shaders be used for?

    - by Bane
    I'm not really a 3D person, and I've only used shaders a little in some Three.js examples, and so far I've got an impression that they are only being used for the graphical part of the equation. Although, the (quite cryptic) Wikipedia article and some other sources lead me to believe that they can be used for more than just graphical effects, ie, to program the GPU (Wikipedia). So, the GPU is still a processor, right? With a larger and a different instruction set for easier and faster vector manipulation, but still a processor. Can I use shaders to make regular programs (provided I've got access to the video memory, which is probable)? Edit: regular programs == "Applications", ie create windows/console programs, or at least have some way of drawing things on the screen, maybe even taking user input.

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  • Drag Gestures - fractional delta values

    - by Den
    I have an issue with objects moving roughly twice as far as expected when dragging them. I am comparing my application to the standard TouchGestureSample sample from MSDN. For some reason in my application gesture samples have fractional positions and deltas. Both are using same Microsoft.Xna.Framework.Input.Touch.dll, v4.0.30319. I am running both apps using standard Windows Phone Emulator. I am setting my break point immediately after this line of code in a simple Update method: GestureSample gesture = TouchPanel.ReadGesture(); Typical values in my app: Delta = {X:-13.56522 Y:4.166667} Position = {X:184.6956 Y:417.7083} Typical values in sample app: Delta = {X:7 Y:16} Position = {X:497 Y:244} Have anyone seen this issue? Does anyone have any suggestions? Thank you.

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  • Farseer: Cutting body from texture

    - by Robin Betka
    Is it possible to cut a body from a texture in Farseer 3.0? I have a texture converted to a body with multiple fixtures ( using BayazitDecomposer, CreatePolygon method, ..) and can even do it as a BreakableBody. But when I try to cut it with the cutting tool, the fixture itself gets cutted but it's connections get discarded! So when I have 14 fixtures, and cut fixture 3 for example, fixture 3 gets cutted but 1,2 and 3-14 just go away. Is there a way to do it? It would work already if I could convert the texture into a body with 1 fixture only, but I haven't figured out it that's possible. BayazitDecomposer creates the multiple verticles, but letting it away creates something weird and I get assert messages all the time. I know I couldn't break it that way but I don't need that anyway when I could cut it. The breaking is just the work around I'm using now. Extending the cuttingtool to support multiple fixtures is very hard especially when you consider that in one cut multiple fixtures could be cutted and then connected again.

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  • Applying Textures to Hexagonal Tiles Seamlessly

    - by PATRY
    I'm doing a tactical game (X-Com / Fallout style) for fun. I've decided to use a hexagonal map, but I'm having a graphic problem. My current map display is HUD-like, with only the border of the map cells displayed, without any texture. it's simple and allow for display of different types of informations by varying the color of the border. For exemple the "danger view mode" displays the borders with a color going from green (no damage possible) to red (prob of damage 90%). Now, It's a bit hard to differentiate the kind of tile the player is on. I could put a plain color (green is grass, pale blue is water...), but this is going to limit the possibilities. Thus, i would like to display a texture on my tiles. Since the map are generated, i can not use a picture for the whole map with the HUD over. So, my question is : does any one knows how i could generate the sealess hexagonal textures (algo or plugin), or if there is a site with some hexagonal tiles ?

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  • Software design of a browser-based strategic MMO game

    - by Mehran
    I wonder if there are any known tested software designs for Travian-like browser-based strategic MMO games? I mean how would they implement the server of such games or what is stored in database and what is stored in RAM? Is the state of the world stored in one piece or is it distributed among a number of storage? Does anyone know a resource to study the problems and solutions of creating such games? [UPDATE] Suggested in comments, I'm going to give an example how would I design such a project. Even though I'm not sure if I'm proposing the right one. Having stored the world state in a MongoDB, I would implement an event collection in which all the changes to the world will register. Changes that are meant to happen in the future will come with an action date set to the future and those that are to be carried out immediately will be set to now. Having this datastore as the central point of the system, players will issue their actions as events inserted in datastore. At the other end of the system, I'll have a constant-running software taking out events out of the datastore which are due to be carried out and not done yet. Executing an event means apply some update on the world's state and thus the datastore. As scalable as this design sounds, I'm not sure if it will be worth implementing. For one, it is pointless to cache the datastore as most of updates happen once without any follow ups. For instance if you have the growth of resources in your game, you'll be updating the whole world state periodically in which case, having incorporated a cache, you are keeping the whole world in RAM (which most likely is impossible). So can someone come up with a better design?

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  • How to create an extensible rope in Box2D?

    - by Thomas
    Let's say I'm trying to create a ninja lowering himself down a rope, or pulling himself back up, all whilst he might be swinging from side to side or hit by objects. Basically like http://ninja.frozenfractal.com/ but with Box2D instead of hacky JavaScript. Ideally I would like to use a rope joint in Box2D that allows me to change the length after construction. The standard Box2D RopeJoint doesn't offer that functionality. I've considered a PulleyJoint, connecting the other end of the "pulley" to an invisible kinematic body that I can control to change the length, but PulleyJoint is more like a rod than a rope: it constrains maximum length, but unlike RopeJoint it constrains the minimum as well. Re-creating a RopeJoint every frame using a new length is rather inefficient, and I'm not even sure it would work properly in the simulation. I could create a "chain" of bodies connected by RotationJoints but that is also less efficient, and less robust. I also wouldn't be able to change the length arbitrarily, but only by adding and removing a whole number of links, and it's not obvious how I would connect the remainder without violating existing joints. This sounds like something that should be straightforward to do. Am I overlooking something?

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  • Car animations in Frogger on Javascript

    - by Mijoro Nicolas Rasoanaivo
    I have to finish a Frogger game in Javascript for my engineering school degree, but I don't know how to animate the cars. Right now I tried to manipulate the CSS, the DOM, I wrote a script with a setTimeout(), but none of them works.Can I have some help please? Here's my code and my CSS: <html> <head> <title>Image d&eacute;filante</title> <link rel="stylesheet" type="text/css" href="map_style.css"/> </head> <body onload="start()"> <canvas id="jeu" width="800" height="450"> </canvas> <img id="voiture" class="voiture" src="car.png" onload="startTimerCar()"> <img id="voiture2" class="voiture" src="car.png" onload="startTimerCar()"> <img id="voiture3" class="voiture" src="car.png" onload="startTimerCar()"> <img id="bigrig" class="bigrig" src="bigrig.png" onload="startTimerBigrig()"> <img id="bigrig2" class="bigrig" src="bigrig.png" onload="startTimerBigrig()"> <img id="bigrig3" class="bigrig" src="bigrig.png" onload="startTimerBigrig()"> <img id="hotrod" src="hotrod.png" onload="startTimerHotrod()"> <img id="hotrod2" src="hotrod.png" onload="startTimerHotrod()"> <img id="turtle" src="turtles_diving.png" onload="startTimerTurtle()"> <img id="turtle2" src="turtles_diving.png" onload="startTimerTurtle()"> <img id="turtle3" src="turtles_diving.png" onload="startTimerTurtle()"> <img id="small" src="log_small.png" onload="startTimerSmall()"> <img id="small2" src="log_small.png" onload="startTimerSmall()"> <img id="small3" src="log_small.png" onload="startTimerSmall()"> <img id="small4" src="log_small.png" onload="startTimerSmall()"> <img id="med" src="log_medium.png" onload="startTimerMedium()"> <img id="med2" src="log_medium.png" onload="startTimerMedium()"> <img id="med3" src="log_medium.png" onload="startTimerMedium()"> <script type="text/javascript"> var X = 1; var timer; function start(){ setInterval(init,10); document.onkeydown = move; var canvas = document.getElementById('jeu'); var context = canvas.getContext('2d'); var frog = document.getElementById('frog'); var posX_frog = 415; var posY_frog = 400; var voiture = [document.getElementById('voiture'),document.getElementById('voiture2'),document.getElementById('voiture3')]; var bigrig = [document.getElementById('bigrig'),document.getElementById('bigrig2'),document.getElementById('bigrig3')]; var hotrod = [document.getElementById('hotrod'),document.getElementById('hotrod2')]; var turtle = [document.getElementById('turtle'),document.getElementById('turtle2'),document.getElementById('turtle3')]; var small = [document.getElementById('small'),document.getElementById('small2'),document.getElementById('small3'),document.getElementById('small4')]; var med = [document.getElementById('med'),document.getElementById('med2'),document.getElementById('med3')]; function init() { context.fillStyle = "#AEEE00"; context.fillRect(0,0,800,50); context.fillRect(0,200,800,50); context.fillRect(0,400,800,50); context.fillStyle = "#046380"; context.fillRect(0,50,800,150); context.fillStyle = "#000000"; context.fillRect(0,250,800,150); var img= new Image(); img.src="./frog.png"; context.drawImage(img,posX_frog, posY_frog, 46, 38); } function move(event){ if (event.keyCode == 39){ if( posX_frog < 716 ){ posX_frog += 50; } } if(event.keyCode == 37){ if( posX_frog >25 ){ posX_frog -= 50; } } if (event.keyCode == 38){ if( posY_frog > 10 ){ posY_frog -= 50; } } if(event.keyCode == 40){ if( posY_frog <400 ){ posY_frog += 50; } } } } </script> </body> And my map_css: #jeu{ z-index:10; width: 800px; height: 450px; border: 2px black solid; overflow: hidden; position: relative; transition:width 2s; -moz-transition:width 2s; /* Firefox 4 */ -webkit-transition:width 2s; /* Safari and Chrome */ } #voiture{ z-index: 100; position: absolute; top: 315px; left: 48px; transition-timing-function: linear; -webkit-transition-timing-function: linear; -moz-transition-timing-function: linear; } #voiture2{ z-index: 100; position: absolute; top: 315px; left: 144px; } #voiture3{ z-index: 100; position: absolute; top: 315px; left: 240px; } #bigrig{ z-index: 100; position: absolute; top: 365px; left: 200px; } #bigrig2{ z-index: 100; position: absolute; top: 365px; left: 400px; } #bigrig3{ z-index: 100; position: absolute; top: 365px; left: 600px; } #hotrod{ z-index: 100; position: absolute; top: 265px; left: 200px; } #hotrod2{ z-index: 100; position: absolute; top: 265px; left: 500px; } #hotrod3{ z-index: 100; position: absolute; top: 265px; left: 750px; } #turtle{ z-index: 100; position: absolute; top: 175px; left: 50px; } #turtle2{ z-index: 100; position: absolute; top: 175px; left: 450px; } #turtle3{ z-index: 100; position: absolute; top: 175px; left: 250px; } #small{ z-index: 100; position: absolute; top: 125px; left: 20px; } #small2{ z-index: 100; position: absolute; top: 125px; left: 220px; } #small3{ z-index: 100; position: absolute; top: 125px; left: 420px; } #small4{ z-index: 100; position: absolute; top: 125px; left: 620px; } #med{ z-index: 100; position: absolute; top: 75px; left: 120px; } #med2{ z-index: 100; position: absolute; top: 75px; left: 320px; } #med3{ z-index: 100; position: absolute; top: 75px; left: 520px; } I had to say that I'm in the obligation to code in HTML5, CSS3, and Javascript but not jQuery, who is way more easier, I already created games in jQuery... It takes me too much time and too much code lines right here.

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  • Error in my Separating Axis Theorem collision code

    - by Holly
    The only collision experience i've had was with simple rectangles, i wanted to find something that would allow me to define polygonal areas for collision and have been trying to make sense of SAT using these two links Though i'm a bit iffy with the math for the most part i feel like i understand the theory! Except my implementation somewhere down the line must be off as: (excuse the hideous font) As mentioned above i have defined a CollisionPolygon class where most of my theory is implemented and then have a helper class called Vect which was meant to be for Vectors but has also been used to contain a vertex given that both just have two float values. I've tried stepping through the function and inspecting the values to solve things but given so many axes and vectors and new math to work out as i go i'm struggling to find the erroneous calculation(s) and would really appreciate any help. Apologies if this is not suitable as a question! CollisionPolygon.java: package biz.hireholly.gameplay; import android.graphics.Canvas; import android.graphics.Color; import android.graphics.Paint; import biz.hireholly.gameplay.Types.Vect; public class CollisionPolygon { Paint paint; private Vect[] vertices; private Vect[] separationAxes; int x; int y; CollisionPolygon(Vect[] vertices){ this.vertices = vertices; //compute edges and separations axes separationAxes = new Vect[vertices.length]; for (int i = 0; i < vertices.length; i++) { // get the current vertex Vect p1 = vertices[i]; // get the next vertex Vect p2 = vertices[i + 1 == vertices.length ? 0 : i + 1]; // subtract the two to get the edge vector Vect edge = p1.subtract(p2); // get either perpendicular vector Vect normal = edge.perp(); // the perp method is just (x, y) => (-y, x) or (y, -x) separationAxes[i] = normal; } paint = new Paint(); paint.setColor(Color.RED); } public void draw(Canvas c, int xPos, int yPos){ for (int i = 0; i < vertices.length; i++) { Vect v1 = vertices[i]; Vect v2 = vertices[i + 1 == vertices.length ? 0 : i + 1]; c.drawLine( xPos + v1.x, yPos + v1.y, xPos + v2.x, yPos + v2.y, paint); } } public void update(int xPos, int yPos){ x = xPos; y = yPos; } /* consider changing to a static function */ public boolean intersects(CollisionPolygon p){ // loop over this polygons separation exes for (Vect axis : separationAxes) { // project both shapes onto the axis Vect p1 = this.minMaxProjection(axis); Vect p2 = p.minMaxProjection(axis); // do the projections overlap? if (!p1.overlap(p2)) { // then we can guarantee that the shapes do not overlap return false; } } // loop over the other polygons separation axes Vect[] sepAxesOther = p.getSeparationAxes(); for (Vect axis : sepAxesOther) { // project both shapes onto the axis Vect p1 = this.minMaxProjection(axis); Vect p2 = p.minMaxProjection(axis); // do the projections overlap? if (!p1.overlap(p2)) { // then we can guarantee that the shapes do not overlap return false; } } // if we get here then we know that every axis had overlap on it // so we can guarantee an intersection return true; } /* Note projections wont actually be acurate if the axes aren't normalised * but that's not necessary since we just need a boolean return from our * intersects not a Minimum Translation Vector. */ private Vect minMaxProjection(Vect axis) { float min = axis.dot(new Vect(vertices[0].x+x, vertices[0].y+y)); float max = min; for (int i = 1; i < vertices.length; i++) { float p = axis.dot(new Vect(vertices[i].x+x, vertices[i].y+y)); if (p < min) { min = p; } else if (p > max) { max = p; } } Vect minMaxProj = new Vect(min, max); return minMaxProj; } public Vect[] getSeparationAxes() { return separationAxes; } public Vect[] getVertices() { return vertices; } } Vect.java: package biz.hireholly.gameplay.Types; /* NOTE: Can also be used to hold vertices! Projections, coordinates ect */ public class Vect{ public float x; public float y; public Vect(float x, float y){ this.x = x; this.y = y; } public Vect perp() { return new Vect(-y, x); } public Vect subtract(Vect other) { return new Vect(x - other.x, y - other.y); } public boolean overlap(Vect other) { if(y > other.x && other.y > x){ return true; } return false; } /* used specifically for my SAT implementation which i'm figuring out as i go, * references for later.. * http://www.gamedev.net/page/resources/_/technical/game-programming/2d-rotated-rectangle-collision-r2604 * http://www.codezealot.org/archives/55 */ public float scalarDotProjection(Vect other) { //multiplier = dot product / length^2 float multiplier = dot(other) / (x*x + y*y); //to get the x/y of the projection vector multiply by x/y of axis float projX = multiplier * x; float projY = multiplier * y; //we want to return the dot product of the projection, it's meaningless but useful in our SAT case return dot(new Vect(projX,projY)); } public float dot(Vect other){ return (other.x*x + other.y*y); } }

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  • Understanding how OpenGL blending works

    - by yuumei
    I am attempting to understand how OpenGL (ES) blending works. I am finding it difficult to understand the documentation and how the results of glBlendFunc and glBlendEquation effect the final pixel that is written. Do the source and destination out of glBlendFunc get added together with GL_FUNC_ADD by default? This seems wrong because "basic" blending of GL_ONE, GL_ONE would output 2,2,2,2 then (Source giving 1,1,1,1 and dest giving 1,1,1,1). I have written the following pseudo-code, what have I got wrong? struct colour { float r, g, b, a; }; colour blend_factor( GLenum factor, colour source, colour destination, colour blend_colour ) { colour colour_factor; float i = min( source.a, 1 - destination.a ); // From http://www.khronos.org/opengles/sdk/docs/man/xhtml/glBlendFunc.xml switch( factor ) { case GL_ZERO: colour_factor = { 0, 0, 0, 0 }; break; case GL_ONE: colour_factor = { 1, 1, 1, 1 }; break; case GL_SRC_COLOR: colour_factor = source; break; case GL_ONE_MINUS_SRC_COLOR: colour_factor = { 1 - source.r, 1 - source.g, 1 - source.b, 1 - source.a }; break; // ... } return colour_factor; } colour blend( colour & source, colour destination, GLenum source_factor, // from glBlendFunc GLenum destination_factor, // from glBlendFunc colour blend_colour, // from glBlendColor GLenum blend_equation // from glBlendEquation ) { colour source_colour = blend_factor( source_factor, source, destination, blend_colour ); colour destination_colour = blend_factor( destination_factor, source, destination, blend_colour ); colour output; // From http://www.khronos.org/opengles/sdk/docs/man/xhtml/glBlendEquation.xml switch( blend_equation ) { case GL_FUNC_ADD: output = add( source_colour, destination_colour ); case GL_FUNC_SUBTRACT: output = sub( source_colour, destination_colour ); case GL_FUNC_REVERSE_SUBTRACT: output = sub( destination_colour, source_colour ); } return output; } void do_pixel() { colour final_colour; // Blending if( enable_blending ) { final_colour = blend( current_colour_output, framebuffer[ pixel ], ... ); } else { final_colour = current_colour_output; } } Thanks!

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  • How do I properly use multithreading with Nvidia PhysX?

    - by xcrypt
    I'm having a multithreading problem with Nvidia PhysX. the SDK requires that you call Simulate() (starts computing new physics positions within a new thread) and FetchResults() (waits 'till the physics computations are done). Inbetween Simulate() and FetchResults() you may not "compute new physics". It is proposed (in a sample) that we create a game loop as such: Logic (you may calculate physics here and other stuff) Render + Simulate() at start of Render call and FetchResults at end of Render() call However, this has given me various little errors that stack up: since you actually render the scene that was computed in the previous iteration in the game loop. Does anyone have a solution to this?

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  • Get coordinates of arraylist

    - by opiop65
    Here's my map class: public class map{ public static final int CLEAR = 0; public static final ArrayList<Integer> STONE = new ArrayList<Integer>(); public static final int GRASS = 2; public static final int DIRT = 3; public static final int WIDTH = 32; public static final int HEIGHT = 24; public static final int TILE_SIZE = 25; // static int[][] map = new int[WIDTH][HEIGHT]; ArrayList<ArrayList<Integer>> map = new ArrayList<ArrayList<Integer>>(WIDTH * HEIGHT); enum tiles { air, grass, stone, dirt } Image air, grass, stone, dirt; Random rand = new Random(); public Map() { /* default map */ /*for(int y = 0; y < WIDTH; y++){ map[y][y] = (rand.nextInt(2)); System.out.println(map[y][y]); }*/ /*for (int y = 18; y < HEIGHT; y++) { for (int x = 0; x < WIDTH; x++) { map[x][y] = STONE; } } for (int y = 18; y < 19; y++) { for (int x = 0; x < WIDTH; x++) { map[x][y] = GRASS; } } for (int y = 19; y < 20; y++) { for (int x = 0; x < WIDTH; x++) { map[x][y] = DIRT; } }*/ for (int y = 0; y < HEIGHT; y++) { for(int x = 0; x < WIDTH; x++){ map.set(x * WIDTH + y, STONE); } } try { init(null, null); } catch (SlickException e) { e.printStackTrace(); } render(null, null, null); } public void init(GameContainer gc, StateBasedGame sbg) throws SlickException { air = new Image("res/air.png"); grass = new Image("res/grass.png"); stone = new Image("res/stone.png"); dirt = new Image("res/dirt.png"); } public void render(GameContainer gc, StateBasedGame sbg, Graphics g) { for (int x = 0; x < WIDTH; x++) { for (int y = 0; y < HEIGHT; y++) { switch (map.get(x * WIDTH + y)) { case CLEAR: air.draw(x * TILE_SIZE, y * TILE_SIZE, TILE_SIZE, TILE_SIZE); break; case STONE: stone.draw(x * TILE_SIZE, y * TILE_SIZE, TILE_SIZE, TILE_SIZE); break; case GRASS: grass.draw(x * TILE_SIZE, y * TILE_SIZE, TILE_SIZE, TILE_SIZE); break; case DIRT: dirt.draw(x * TILE_SIZE, y * TILE_SIZE, TILE_SIZE, TILE_SIZE); break; } } } } public static boolean blocked(float x, float y) { return map[(int) x][(int) y] == STONE; } public static Rectangle blockBounds(int x, int y) { return (new Rectangle(x, y, TILE_SIZE, TILE_SIZE)); } } Specifically I am looking at this: for (int x = 0; x < WIDTH; x++) { for (int y = 0; y < HEIGHT; y++) { switch (map.get(x * WIDTH + y).intValue()) { case CLEAR: air.draw(x * TILE_SIZE, y * TILE_SIZE, TILE_SIZE, TILE_SIZE); break; case STONE: stone.draw(x * TILE_SIZE, y * TILE_SIZE, TILE_SIZE, TILE_SIZE); break; case GRASS: grass.draw(x * TILE_SIZE, y * TILE_SIZE, TILE_SIZE, TILE_SIZE); break; case DIRT: dirt.draw(x * TILE_SIZE, y * TILE_SIZE, TILE_SIZE, TILE_SIZE); break; } } } How can I access the coordinates of my arraylist map and then draw the tiles to the screen? Thanks!

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