Search Results

Search found 26774 results on 1071 pages for 'distributed development'.

Page 464/1071 | < Previous Page | 460 461 462 463 464 465 466 467 468 469 470 471  | Next Page >

• Position Reconstruction from Depth by inverting Perspective Projection

  - by user1294203

  I had some trouble reconstructing position from depth sampled from the depth buffer. I use the equivalent of gluPerspective in GLM. The code in GLM is: template GLM_FUNC_QUALIFIER detail::tmat4x4 perspective ( valType const & fovy, valType const & aspect, valType const & zNear, valType const & zFar ) { valType range = tan(radians(fovy / valType(2))) * zNear; valType left = -range * aspect; valType right = range * aspect; valType bottom = -range; valType top = range; detail::tmat4x4 Result(valType(0)); Result[0][0] = (valType(2) * zNear) / (right - left); Result[1][2] = (valType(2) * zNear) / (top - bottom); Result[2][3] = - (zFar + zNear) / (zFar - zNear); Result[2][4] = - valType(1); Result[3][5] = - (valType(2) * zFar * zNear) / (zFar - zNear); return Result; } There doesn't seem to be any errors in the code. So I tried to invert the projection, the formula for the z and w coordinates after projection are: and dividing z' with w' gives the post-projective depth (which lies in the depth buffer), so I need to solve for z, which finally gives: Now, the problem is I don't get the correct position (I have compared the one reconstructed with a rendered position). I then tried using the respective formula I get by doing the same for this Matrix. The corresponding formula is: For some reason, using the above formula gives me the correct position. I really don't understand why this is the case. Have I done something wrong? Could someone enlighten me please?

  Read the article

• (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

  Read the article

• 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?

  Read the article

• 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.

  Read the article

• 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!

  Read the article

• 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

  Read the article

• How much server bandwidth does an average RTS game require per month?

  - by Nat Weiss

  My friend and I are going to write a multiplayer, multiplatform RTS game and are currently analyzing the costs of going with a client-server architecture. The game will have a small map with mostly characters, not buildings (think of DotA or League of Legends). The authoritative game logic will run on the server and message packet sizes will be highly optimized. We'd like to know approximately how much server bandwidth our proposed RTS game would use on a monthly basis, considering these theoretical constants: 100 concurrent users maximum 8 players maximum per game 10 ticks per second Bonus: If you can tell us approximately how much server RAM this kind of game would use that would also help a great deal. Thanks in advance.

  Read the article

• What 2D game engines are there available for C++?

  - by dysoco

  I just realized there are not C++ 2D Game Engines that I know of. For example, something like Pygame in Python, or Slick2D in Java. We have the following: SDL - Too low level, not a Game Engine SFML - Handles more things than SDL and it's more modern, but still not a Game Engine. I like it, but I have found it a little bit buggy with the 2.0 version. Irrlitch - It's a Game Engine, but 3D focused. Ogre3D - Same as Irrlitch Allegro - This is a Game Engine, but it's C based, I'd like a modern C++ library. Monocle Engine - This looks like what I need... but sadly there is no Documentation, no community... nothing, all I have is the Github repo. So, do you know any ? I'd like to use C++, not C#, not Java: I'm just more comfortable with C++.

  Read the article

• 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.

  Read the article

• Is 2 lines of push/pop code for each pre-draw-state too many?

  - by Griffin

  I'm trying to simplify vector graphics management in XNA; currently by incorporating state preservation. 2X lines of push/pop code for X states feels like too many, and it just feels wrong to have 2 lines of code that look identical except for one being push() and the other being pop(). The goal is to eradicate this repetitiveness,and I hoped to do so by creating an interface in which a client can give class/struct refs in which he wants restored after the rendering calls. Also note that many beginner-programmers will be using this, so forcing lambda expressions or other advanced C# features to be used in client code is not a good idea. I attempted to accomplish my goal by using Daniel Earwicker's Ptr class: public class Ptr<T> { Func<T> getter; Action<T> setter; public Ptr(Func<T> g, Action<T> s) { getter = g; setter = s; } public T Deref { get { return getter(); } set { setter(value); } } } an extension method: //doesn't work for structs since this is just syntatic sugar public static Ptr<T> GetPtr <T> (this T obj) { return new Ptr<T>( ()=> obj, v=> obj=v ); } and a Push Function: //returns a Pop Action for later calling public static Action Push <T> (ref T structure) where T: struct { T pushedValue = structure; //copies the struct data Ptr<T> p = structure.GetPtr(); return new Action( ()=> {p.Deref = pushedValue;} ); } However this doesn't work as stated in the code. How might I accomplish my goal? Example of code to be refactored: protected override void RenderLocally (GraphicsDevice device) { if (!(bool)isCompiled) {Compile();} //TODO: make sure state settings don't implicitly delete any buffers/resources RasterizerState oldRasterState = device.RasterizerState; DepthFormat oldFormat = device.PresentationParameters.DepthStencilFormat; DepthStencilState oldBufferState = device.DepthStencilState; { //Rendering code } device.RasterizerState = oldRasterState; device.DepthStencilState = oldBufferState; device.PresentationParameters.DepthStencilFormat = oldFormat; }

  Read the article

• 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.

  Read the article

• Making AI jump on a spot effectively

  - by Pasquale Sada

  How to calculate, in 3D environment, the closest point, from which an AI character can jump onto a platform? Setup I have an initial velocity V(Vx,Vy,VZ) and a spot where the character stands still at S(Sx,Sy,Sz). What I'm trying to achieve is a successful jump on a spot E(Ex,Ey,Ez) where you have clicked on(only lower or higher spot, because I've in place a simple steering behavior for even terrains). There are no obstacles around. I've implemented a formula that can make him jump in a precise way on a spot but you need to declare an angle: the problem arise when the selected spot is straight above your head. It' pretty lame that the char hang there and can reach a thing that is 1cm above is head. I'll share the code I'm using: Vector3 dir = target - transform.position; // get target direction float h = dir.y; // get height difference dir.y = 0; // retain only the horizontal direction float dist = dir.magnitude ; // get horizontal distance float a = angle * Mathf.Deg2Rad; // convert angle to radians dir.y = dist * Mathf.Tan(a); // set dir to the elevation angle dist += h / Mathf.Tan(a); // correct for small height differences // calculate the velocity magnitude float vel = Mathf.Sqrt(dist * Physics.gravity.magnitude / Mathf.Sin(2 *a)); return vel * dir.normalized; Ended up using the lowest angle (20 degree) and checking for collision on the trajectory. If found any increase the angle. Here some code (to improve the code maybe must stop the check at the highest point of the curve): Vector3 BallisticVel(Vector3 target, float angle) { Vector3 dir = target - transform.position; // get target direction float h = dir.y; // get height difference dir.y = 0; // retain only the horizontal direction float dist = dir.magnitude ; // get horizontal distance float a = angle * Mathf.Deg2Rad; // convert angle to radians dir.y = dist * Mathf.Tan(a); // set dir to the elevation angle dist += h / Mathf.Tan(a); // correct for small height differences // calculate the velocity magnitude float vel = Mathf.Sqrt(dist * Physics.gravity.magnitude / Mathf.Sin(2 * a)); return vel * dir.normalized; } Vector3 TrajectoryPoint(Vector3 startingPosition, Vector3 startingVelocity, float n ) { float t = 1/60 ; // seconds per time step Vector3 stepVelocity = t * startingVelocity; // m/s Vector3 stepGravity = t * t * Physics.gravity; // m/s/s return startingPosition + n * stepVelocity + 0.5f * (n*n+n) * stepGravity; } bool CheckTrajectory(Vector3 startingPosition,Vector3 target, float angle_jump) { Debug.Log("checking"); if(angle_jump < 80f) { Debug.Log("if"); Vector3 startingVelocity = BallisticVel(target, angle_jump); for (int i = 0; i < 180; i++) { //Debug.Log(i); Vector3 trajectoryPosition = TrajectoryPoint( startingPosition, startingVelocity, i ); if(Physics.Raycast(trajectoryPosition,Vector3.forward,safeDistance)) { angle_jump += 10; break; // restart loop with the new angle } else continue; } return true; JumpVelocity = BallisticVel(target, angle_jump); } return false; }

  Read the article

• How to move from home page screen to the next menu screen on clicking a particular image in XNA4.0?

  - by Raj

  I m new 2 XNA game pgming(also C#)....I want 2 create a main page with some buttons and on clicking a particular button, it should goto another screen whr there r some buttons to select which should inturn goto the game screen on clicking....Whether I can put all the codes in the "game1.cs" or create new class for every page....Pls help... I've jus went through some pages in "Learning xna4.0" by o'reilly...If there s any other gud tutorials, pls suggest me...

  Read the article

• Love2D engine for Lua; What about 3D?

  - by shadowprotocol

  Lua has been really awesome to learn, it's so simple. I really enjoy scripting languages, and I had an equally enjoyable time learning Python. The Love engine, http://love2d.org/, is really awesome, but I'm looking for something that can handle 3D as well. Is there anything that accommodates 3D in Lua? I'm still intrigued by the particle system of LOVE anyway and may just turn my idea into a 2D project with Particle lighting :) EDIT: I removed comments about Python - I want this to be a Lua topic. Thanks

  Read the article

• Particle effect after the bullet

  - by Siddharth

  In my game, I fire a bullet from the gun along with that I generate a particle behind the bullet so that I look like fire effect after the bullet. But my problem is that the position I got from the bullet was distance in place. So basically I want to say that the bullet speed was high for that reason I got coordinate for the particle generation was far from each other like dot dot effect. But I want continuous flow of particle behind the bullet. So please provide any guidance for my problem

  Read the article

• Why does my 3D model not translate the way I expect? [closed]

  - by ChocoMan

  In my first image, my model displays correctly: But when I move the model's position along the Z-axis (forward) I get this, yet the Y-axis doesnt change. An if I keep going, the model disappears into the ground: Any suggestions as to how I can get the model to translate properly visually? Here is how Im calling the model and the terrain in draw(): cameraPosition = new Vector3(camX, camY, camZ); // Copy any parent transforms. Matrix[] transforms = new Matrix[mShockwave.Bones.Count]; mShockwave.CopyAbsoluteBoneTransformsTo(transforms); Matrix[] ttransforms = new Matrix[terrain.Bones.Count]; terrain.CopyAbsoluteBoneTransformsTo(ttransforms); // Draw the model. A model can have multiple meshes, so loop. foreach (ModelMesh mesh in mShockwave.Meshes) { // This is where the mesh orientation is set, as well // as our camera and projection. foreach (BasicEffect effect in mesh.Effects) { effect.EnableDefaultLighting(); effect.PreferPerPixelLighting = true; effect.World = transforms[mesh.ParentBone.Index] * Matrix.CreateRotationY(modelRotation) * Matrix.CreateTranslation(modelPosition); // Looking at the model (picture shouldnt change other than rotation) effect.View = Matrix.CreateLookAt(cameraPosition, modelPosition, Vector3.Up); effect.Projection = Matrix.CreatePerspectiveFieldOfView( MathHelper.ToRadians(45.0f), aspectRatio, 1.0f, 10000.0f); effect.TextureEnabled = true; } // Draw the mesh, using the effects set above. prepare3d(); mesh.Draw(); } //Terrain test foreach (ModelMesh meshT in terrain.Meshes) { foreach (BasicEffect effect in meshT.Effects) { effect.EnableDefaultLighting(); effect.PreferPerPixelLighting = true; effect.World = ttransforms[meshT.ParentBone.Index] * Matrix.CreateRotationY(0) * Matrix.CreateTranslation(terrainPosition); // Looking at the model (picture shouldnt change other than rotation) effect.View = Matrix.CreateLookAt(cameraPosition, terrainPosition, Vector3.Up); effect.Projection = Matrix.CreatePerspectiveFieldOfView( MathHelper.ToRadians(45.0f), aspectRatio, 1.0f, 10000.0f); effect.TextureEnabled = true; } // Draw the mesh, using the effects set above. prepare3d(); meshT.Draw(); DrawText(); } base.Draw(gameTime); } I'm suspecting that there may be something wrong with how I'm handling my camera. The model rotates fine on its Y-axis.

  Read the article

• 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

  Read the article

• Setting Krypton Light to Screen Pixels

  - by Adam Jerrett

  So a few days back, I started playing around with Krypton XNA for 2D lighting in my game. I noticed in general, that spawning a light at (0,0) with Krypton causes the light to appear in, pretty much, the centre of the game screen. Is there any way to change this so a Krypton light's "starting point" at [0,0] would spawn at the top left of the screen, and thus follow the standard screen co-ordinates for position? I ask because currently I'm busy working on my game where my spawn point is [512,512]. With hard code, the closest I've got to the light being "central" to this point is the vector position [12,-20], which makes no sense and is impossible to craft, mathematically, if I want the light to move with the camera (the position [480,512] maps roughly to [10,-20]). So, is there any way to "normalise" the krypton lights to use standard screen co-ordinates? If you guys can, play around with the demo from the site and please see if you can find anything out about it. Documentation on the engine is rather scarce, so it's difficult to find anything relevant to my "pixel-perfect" need. It might just also be something in the code with regards to the matrices that I'm not fully understanding. Any help would be useful. Thanks.

  Read the article

• 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?

  Read the article

• 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?

  Read the article

• Issues with shooting in a HTML5 platformer game

  - by fnx

  I'm coding a 2D sidescroller using only JavaScript and HTML5 canvas, and in my game I have two problems with shooting: 1) Player shoots continous stream of bullets. I want that player can shoot only a single bullet even though the shoot-button is being held down. 2) Also, I get an error "Uncaught TypeError: Cannot call method 'draw' of undefined" when all the bullets are removed. My shooting code goes like this: When player shoots, I do game.bullets.push(new Bullet(this, this.scale)); and after that: function Bullet(source, dir) { this.id = "bullet"; this.width = 10; this.height = 3; this.dir = dir; if (this.dir == 1) { this.x = source.x + source.width - 5; this.y = source.y + 16; } if (this.dir == -1) { this.x = source.x; this.y = source.y + 16; } } Bullet.prototype.update = function() { if (this.dir == 1) this.x += 8; if (this.dir == -1) this.x -= 8; for (var i in game.enemies) { checkCollisions(this, game.enemies[i]); } // Check if bullet leaves the viewport if (this.x < game.viewX * 32 || this.x > (game.viewX + game.tilesX) * 32) { removeFromList(game.bullets, this); } } Bullet.prototype.draw = function() { // bullet flipping uses orientation of the player var posX = game.player.scale == 1 ? this.x : (this.x + this.width) * -1; game.ctx.scale(game.player.scale, 1); game.ctx.drawImage(gameData.getGfx("bullet"), posX, this.y); } I handle removing with this function: function removeFromList(list, object) { for (i in list) { if (object == list[i]) { list.splice(i, 1); break; } } } And finally, in the main game loop I have this: for (var i in game.bullets) { game.bullets[i].update(); game.bullets[i].draw(); } I have tried adding if (game.bullets.length > 0) to the main game loop before the above draw&update calls, but I still get the same error.

  Read the article

• How do I create a curved line or filled circle or generally a circle using C++/SDL?

  - by NoobScratcher

  Hello I've been trying for ages to make a pixel circle using the putpixel function provided by SDL main website here is that function : void putpixel(int x,int y , int color , SDL_Surface* surface) { unsigned int *ptr = static_cast <unsigned int *> (surface->pixels); int offset = y * (surface->pitch/sizeof(unsigned int)); ptr[offset + x] = color; } and my question is how do I curve a line or create an circle arc of pixels or any other curved shape then a rectangle or singular pixel or line. for example here are some pictures filled pixel circle below enter link description here now my idea was too change the x and y value of the pixel position using + and - to create the curves but in practice didn't provide the correct results what my results are in this is to be able to create a circle that is made out of pixels only nothing else. thank you for anyone who takes the time to read this question thanks! :D

  Read the article

• determine collision angle on a rotating body

  - by jorb

  update: new diagram and updated description I have a contact listener set up to try and determine the side that a collision happened at relative to the a bodies rotation. One way to solve this is to find the value of the yellow angle between the red and blue vectors drawn above. The angle can be found by taking the arc cosine of the dot product of the two vectors (Evan pointed this out). One of my points of confusion is the difference in domain of the atan2 function html canvas coordinates and the Box2d rotation information. I know I have to account for this somehow... SS below questions: Does Box2D provide these angles more directly in the collision information? Am I even on the right track? If so, any hints? I have the following javascript so far: Ship.prototype.onCollide = function (other_ent,cx,cy) { var pos = this.body.GetPosition(); //collision position relative to body var d_cx = pos.x - cx; var d_cy = pos.y - cy; //length of initial vector var len = Math.sqrt(Math.pow(pos.x -cx,2) + Math.pow(pos.y-cy,2)); //body angle - can over rotate hence mod 2*Pi var ang = this.body.GetAngle() % (Math.PI * 2); //vector representing body's angle - same magnitude as the first var b_vx = len * Math.cos(ang); var b_vy = len * Math.sin(ang); //dot product of the two vectors var dot_prod = d_cx * b_vx + d_cy * b_vy; //new calculation of difference in angle - NOT WORKING! var d_ang = Math.acos(dot_prod); var side; if (Math.abs(d_ang) < Math.PI/2 ) side = "front"; else side = "back"; console.log("length",len); console.log("pos:",pos.x,pos.y); console.log("offs:",d_cx,d_cy); console.log("body vec",b_vx,b_vy); console.log("body angle:",ang); console.log("dot product",dot_prod); console.log("result:",d_ang); console.log("side",side); console.log("------------------------"); }

  Read the article

• Are there existing FOSS component-based frameworks?

  - by Tesserex

  The component based game programming paradigm is becoming much more popular. I was wondering, are there any projects out there that offer a reusable component framework? In any language, I guess I don't care about that. It's not for my own project, I'm just curious. Specifically I mean are there projects that include a base Entity class, a base Component class, and maybe some standard components? It would then be much easier starting a game if you didn't want to reinvent the wheel, or maybe you want a GraphicsComponent that does sprites with Direct3D, but you figure it's already been done a dozen times. A quick Googling turns up Rusher. Has anyone heard of this / does anyone use it? If there are no popular ones, then why not? Is it too difficult to make something like this reusable, and they need heavy customization? In my own implementation I found a lot of boilerplate that could be shoved into a framework.

  Read the article

• 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!

  Read the article

< Previous Page | 460 461 462 463 464 465 466 467 468 469 470 471  | Next Page >