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  • Good GUI for OpenGL

    - by Cristina
    I am starting to learn OpenGL with FreeGLUT using the Superbible and the knowledge i have from my elementary graphics to brush up on my skills. To get more from this experience i want to integrate a GUI to overwrite the one FreeGLUT uses, now my question is this: is this thing possible and what library should i use? Some characteristics for the library: Open source Multi-platform (Linux and Windows) C/C++ If you have any other recommendations please feel free to post them along with your answers for my problem.

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  • Omni-directional light shadow mapping with cubemaps in WebGL

    - by Winged
    First of all I must say, that I have read a lot of posts describing an usage of cubemaps, but I'm still confused about how to use them. My goal is to achieve a simple omni-directional (point) light type shading in my WebGL application. I know that there is a lot more techniques (like using Two-Hemispheres or Camera Space Shadow Mapping) which are way more efficient, but for an educational purpose cubemaps are my primary goal. Till now, I have adapted a simple shadow mapping which works with spotlights (with one exception: I don't know how to cut off the glitchy part beyond the reach of a single shadow map texture): glitchy shadow mapping<<< So for now, this is how I understand the usage of cubemaps in shadow mapping: Setup a framebuffer (in case of cubemaps - 6 framebuffers; 6 instead of 1 because every usage of framebufferTexture2D slows down an execution which is nicely described here <<<) and a texture cubemap. Also in WebGL depth components are not well supported, so I need to render it to RGBA first. this.texture = gl.createTexture(); gl.bindTexture(gl.TEXTURE_CUBE_MAP, this.texture); gl.texParameteri(gl.TEXTURE_CUBE_MAP, gl.TEXTURE_MIN_FILTER, gl.LINEAR); gl.texParameteri(gl.TEXTURE_CUBE_MAP, gl.TEXTURE_MAG_FILTER, gl.LINEAR); for (var face = 0; face < 6; face++) gl.texImage2D(gl.TEXTURE_CUBE_MAP_POSITIVE_X + face, 0, gl.RGBA, this.size, this.size, 0, gl.RGBA, gl.UNSIGNED_BYTE, null); gl.bindTexture(gl.TEXTURE_CUBE_MAP, null); this.framebuffer = []; for (face = 0; face < 6; face++) { this.framebuffer[face] = gl.createFramebuffer(); gl.bindFramebuffer(gl.FRAMEBUFFER, this.framebuffer[face]); gl.framebufferTexture2D(gl.FRAMEBUFFER, gl.COLOR_ATTACHMENT0, gl.TEXTURE_CUBE_MAP_POSITIVE_X + face, this.texture, 0); gl.framebufferRenderbuffer(gl.FRAMEBUFFER, gl.DEPTH_ATTACHMENT, gl.RENDERBUFFER, this.depthbuffer); var e = gl.checkFramebufferStatus(gl.FRAMEBUFFER); // Check for errors if (e !== gl.FRAMEBUFFER_COMPLETE) throw "Cubemap framebuffer object is incomplete: " + e.toString(); } Setup the light and the camera (I'm not sure if should I store all of 6 view matrices and send them to shaders later, or is there a way to do it with just one view matrix). Render the scene 6 times from the light's position, each time in another direction (X, -X, Y, -Y, Z, -Z) for (var face = 0; face < 6; face++) { gl.bindFramebuffer(gl.FRAMEBUFFER, shadow.buffer.framebuffer[face]); gl.viewport(0, 0, shadow.buffer.size, shadow.buffer.size); gl.clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT); camera.lookAt( light.position.add( cubeMapDirections[face] ) ); scene.draw(shadow.program); } In a second pass, calculate the projection a a current vertex using light's projection and view matrix. Now I don't know If should I calculate 6 of them, because of 6 faces of a cubemap. ScaleMatrix pushes the projected vertex into the 0.0 - 1.0 region. vDepthPosition = ScaleMatrix * uPMatrixFromLight * uVMatrixFromLight * vWorldVertex; In a fragment shader calculate the distance between the current vertex and the light position and check if it's deeper then the depth information read from earlier rendered shadow map. I know how to do it with a 2D Texture, but I have no idea how should I use cubemap texture here. I have read that texture lookups into cubemaps are performed by a normal vector instead of a UV coordinate. What vector should I use? Just a normalized vector pointing to the current vertex? For now, my code for this part looks like this (not working yet): float shadow = 1.0; vec3 depth = vDepthPosition.xyz / vDepthPosition.w; depth.z = length(vWorldVertex.xyz - uLightPosition) * linearDepthConstant; float shadowDepth = unpack(textureCube(uDepthMapSampler, vWorldVertex.xyz)); if (depth.z > shadowDepth) shadow = 0.5; Could you give me some hints or examples (preferably in WebGL code) how I should build it?

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  • How to move an object using X and Y coordinates in JavaScript

    - by Geroy290
    I am making a 2d game with JavaScript and HTML5 and am trying to move an image that I have drawn with JavaScript like so: //canvas var c = document.getElementById("gameCanvas"); var ctx = c.getContext("2d"); //baseball var baseball = new Image(); baseball.onload = function() { ctx.drawImage(baseball, 400, 425); }; baseball.src = "baseball2.png"; I'm not sure how I would move it though, I have seen many people seem to just type something like ballX and ballY but I don't understand where the actual x and y definition comes from. Here is my code so far: http://jsfiddle.net/xRfua/ I have a different image source but it is a local source so I couldn't include it. Thanks in a dvance for any help!

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  • OpenGL setup on Windows

    - by kevin james
    I have been trying to use OpenGL for two days now. First on Mac, then on Windows. The problem with Mac is that it doesn't support the newer versions of OpenGL. I ran a tutorial that actually did get some things working, but it only works in XCode (i.e., I can't create a new file, paste in the same code, and get it to work). Because of these issues, I moved to Windows. My Windows 7 has OpenGL 4.3, which is the same that is used in alot of other tutorials. However, not one of these tutorials gives any instruction on how to set it up for the first time. I have come across some vague posts saying that some libraries need to be linked. But WHAT libraries, and HOW do I link them? Please help. I am pretty desperate to set this up as this project is due for work soon. I have actually used OpenGL before at my university, but the computers already had everything set up. The project itself is very easy, but setting up OpenGL is not something I know how to do.

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  • cocos2d event handler not fired when reentering scene

    - by Adam Freund
    I am encountering a very strange problem with my cocos2d app. I add a sprite to the page and have an event handler linked to it which replaces the scene with another scene. On that page I have another button to take me back to the original scene. When I am back on the original scene, the eventHandler doesn't get fired when I click on the sprite. Below is the relevant code. Thanks for any help! CCMenuItemImage *backBtnImg = [CCMenuItemImage itemWithNormalImage:@"btn_back.png" selectedImage:@"btn_back_pressed.png" target:self selector:@selector(backButtonTapped:)]; backBtnImg.position = ccp(45, 286); CCMenu *backBtn = [CCMenu menuWithItems:backBtnImg, nil]; backBtn.position = CGPointZero; [self addChild:backBtn]; EventHandler method (doesn't get called when the scene is re-entered). (void)backButtonTapped:(id)sender { NSLog(@"backButtonTapped\n"); CCMenuItemImage *backButton = (CCMenuItemImage *)sender; [backButton setNormalImage:[CCSprite spriteWithFile:@"btn_back_pressed.png"]]; [[CCDirector sharedDirector] replaceScene:[CCTransitionFade transitionWithDuration:.25 scene:[MenuView scene] withColor:ccBLACK]]; }

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  • Change alpha to a Frame in libgdx

    - by Rudy_TM
    I have this batch.draw(currentFrame, x, y, this.parent.originX, this.parent.originY, this.parent.width, this.parent.height, this.scaleX, this.scaleY,this.rotation); I want to apply the alpha that it gets from the method, but theres is not overload from the SpriteBatch class that takes the alpha value, is there some wey to apply it? (i did it this way, because this are animation, and i wanted to control them) in my static ones i apply sprite.draw(SpriteBatch, alpha) Thanks

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  • What is the best way to implement collision detection using Bullet physics engine and a track generated from a curve?

    - by tigrou
    I am developing a small racing game were the track is generated from a curve. As said above, the track is generated, but not infinite. The track of one level could fit with no problem in memory and will contain a reasonably small amount of triangles. For collisions, I would like to use Bullet physics engine and know what is the best way to handle collisions with the track efficiently. NOTE : The track will be stored as a static rigid body (mass = 0). The player will be represented by a sphere shape for collisions. Here is some possibilities i have in mind : Create one rigid body, then, put all triangles of the track (except non collidable stuff) into it. Result : 1 body with many triangles (eg : 30000 triangles) Split the track into several sections (eg: 10 sections). Then, for each section, create a rigid body and put corresponding triangles in it. Result : small amount of bodies with relatively small amount of triangles (eg : 1500 triangles per section). Split the track into many sub-sections (eg : 1200 sections). Here one subsection = very small step when generating the curve. Again for each sub-section, create a body and put triangles in it. Result : many bodies with very small amount of triangles (eg : 20 triangles). Advantage : it could be possible to "extra data" to each of the subsection, that could be used when handling collisions. Same as 2, but only put sections N and N+1 in physics engine (where N = current section where the player is). When player reach section N+1, unload section N and load section N+2 and so on... Issue : harder to implement, problems if the player suddenly "jump" from one section to another (eg : player fly away from section N, and fall on section N + 4 that was underneath : no collision handled, player will fall into void ) Same as 4, but with many sub-sections. Issues : since subsections are very small there will be constantly new bodies added and removed to physics engine at runtime. Possibilities for player to accidently skip some sections and fall into the void are higher than 4.

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  • How to make it so units don't stack up in one location?

    - by Daggio
    So I'm making a game in AS3, it's a strategy DotA-like game (for flash game equivalent, there's UDE) so far so good, I have the A* pathfinding algorithm all sorted out and the minion units move to the desired location as I want them to be. The problem a rise when a unit stops in a node that has already occupied by another friendly unit. Both (or more than two) of them stacks up in one location, it looks like they're one unit. I want to add collision detection so when they collide they don't stack up together. But now they stop when they collide on they way to a node. This isn't good because they won't move at all midway (they won't respond to enemy attacks like that). I've added a deltatime so they only stopped for 2 seconds before they move again to their designated designation. This moves them again but they flicker. Not how I want it. So, like the title said. How to make more than one units don't stack up in a node? And if possible, how to make them not flicker while moving (it's good if they can tell other friendly units on the way and avoid them accordingly)?

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  • My frustum culling is culling from the wrong point [SOLVED]

    - by Xbetas
    I'm having problems with my frustum being in the wrong origin. It follows the rotation of my camera but not the position. In my camera class I'm generating a view-matrix: void Camera::Update() { UpdateViewMatrix(); glMatrixMode(GL_MODELVIEW); //glLoadIdentity(); glLoadMatrixf(GetViewMatrix().m); } Then extracting the planes using the projection matrix and modelview matrix: void UpdateFrustum() { Matrix4x4 projection, model, clip; glGetFloatv(GL_PROJECTION_MATRIX, projection.m); glGetFloatv(GL_MODELVIEW_MATRIX, model.m); clip = model * projection; m_Planes[RIGHT][0] = clip.m[ 3] - clip.m[ 0]; m_Planes[RIGHT][1] = clip.m[ 7] - clip.m[ 4]; m_Planes[RIGHT][2] = clip.m[11] - clip.m[ 8]; m_Planes[RIGHT][3] = clip.m[15] - clip.m[12]; NormalizePlane(RIGHT); m_Planes[LEFT][0] = clip.m[ 3] + clip.m[ 0]; m_Planes[LEFT][1] = clip.m[ 7] + clip.m[ 4]; m_Planes[LEFT][2] = clip.m[11] + clip.m[ 8]; m_Planes[LEFT][3] = clip.m[15] + clip.m[12]; NormalizePlane(LEFT); m_Planes[BOTTOM][0] = clip.m[ 3] + clip.m[ 1]; m_Planes[BOTTOM][1] = clip.m[ 7] + clip.m[ 5]; m_Planes[BOTTOM][2] = clip.m[11] + clip.m[ 9]; m_Planes[BOTTOM][3] = clip.m[15] + clip.m[13]; NormalizePlane(BOTTOM); m_Planes[TOP][0] = clip.m[ 3] - clip.m[ 1]; m_Planes[TOP][1] = clip.m[ 7] - clip.m[ 5]; m_Planes[TOP][2] = clip.m[11] - clip.m[ 9]; m_Planes[TOP][3] = clip.m[15] - clip.m[13]; NormalizePlane(TOP); m_Planes[NEAR][0] = clip.m[ 3] + clip.m[ 2]; m_Planes[NEAR][1] = clip.m[ 7] + clip.m[ 6]; m_Planes[NEAR][2] = clip.m[11] + clip.m[10]; m_Planes[NEAR][3] = clip.m[15] + clip.m[14]; NormalizePlane(NEAR); m_Planes[FAR][0] = clip.m[ 3] - clip.m[ 2]; m_Planes[FAR][1] = clip.m[ 7] - clip.m[ 6]; m_Planes[FAR][2] = clip.m[11] - clip.m[10]; m_Planes[FAR][3] = clip.m[15] - clip.m[14]; NormalizePlane(FAR); } void NormalizePlane(int side) { float length = 1.0/(float)sqrt(m_Planes[side][0] * m_Planes[side][0] + m_Planes[side][1] * m_Planes[side][1] + m_Planes[side][2] * m_Planes[side][2]); m_Planes[side][0] *= length; m_Planes[side][1] *= length; m_Planes[side][2] *= length; m_Planes[side][3] *= length; } And check against it with: bool PointInFrustum(float x, float y, float z) { for(int i = 0; i < 6; i++) { if( m_Planes[i][0] * x + m_Planes[i][1] * y + m_Planes[i][2] * z + m_Planes[i][3] <= 0 ) return false; } return true; } Then i render using: camera->Update(); UpdateFrustum(); int numCulled = 0; for(int i = 0; i < (int)meshes.size(); i++) { if(!PointInFrustum(meshCenter.x, meshCenter.y, meshCenter.z)) { meshes[i]->SetDraw(false); numCulled++; } else meshes[i]->SetDraw(true); } Matrices look like (Camera is at (5, 0, 0)): ModelView [0,0,0.99,0] [0,1,0,0] [-0.99,0,0,0] [0,0,-5,1] Projection [0.814,0,0,0] [0,1.303,0,0] [0,0,-1,0] [0,0,-0.02,0] Clip [0,0,-1,-0.999] [0,1.30,0,0] [-0.814,0,0,0] [0,0,4.98,4.99] What am i doing wrong?

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  • Maya Animated Character export for XNA 4.0 problem

    - by FahidK
    To begin with, I'm trying to export an animated character in .fbx format from Maya 2013 to XNA 4.0 In Maya, The Model has a basic rig and the animations are in clips made in the Trax editor. so the issue i'm having is after selecting the model and the root joint and then hitting export in .fbx format, for some reason when i open the exported .fbx file the joint system is detached from the model with no animation. Btw, i have the animations in clips so that they can be called in code, for example "run","walk","attack". So, what can i do to solve this problem? Thank you.

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  • Balancing agressive invites

    - by Nils Munch
    I am designing a trading card game for mobiles, with the possibility to add cards to your collection using Gems, aquired through victories and inapp purchases. I am thinking to increase the spread of the game with a tracking system on game invites, enabling the user to invite a friend to play the game. If the friend doesn't own the game client (which is free) he will be offered to download it. If he joins the game, the original player earns X amount of gems as an reward. There can only be one player per mobile device, which should rule out some harvesting. My question is, how do you think the structure of this would be recieved ? All invites are mail based, unless the player already exists in the game world (then he gets a ingame invitation.) I have set a flood filter, so a player can only invite a friend (without the client installed) once a month.

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  • Check for bodies within a specific circle in Box2D

    - by ltjax
    I'm trying to find positions to insert new bodies into my world. For that, I'd like to have a "free" spot where this body wouldn't overlap with anything else. So my plan was to sample "random" positions and check whether they overlap with my "potential" new body. Since my bodies are always circular, I'd need to test within a given circle. So far, the only way to use box2d for this seems to use b2World::QueryAABB around my circle and manually doing an overlap test with all the fixtures it gives me (Box2D doesn't event seem to allow me to tap into its overlapping tests?!). It seems to me like Box2D should already provide such functionality - is there a way that lets me do this without reinventing most of the wheel again?

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  • Sorting objects before rendering

    - by dreta
    I'm trying to implement a scene graph and in all the articles i've come across there is talk about object sorting. So you'd sort your objects by "material" for example. Now untill i sat down and started implementing it, i kind of took this for granted, because it made sense. But now i'm wondering what does sorting actually change? In my engine, i have a manager for UBOs, i use those to store data that'll be shared between programs, at the moment that only involves time, camera and projection matrices and lights (i'm not worrying about managing which lights affect which objects ATM). Now for each model i have to change the model to world matrix uniform, no sorting is going to change that. So is the jump from changing this matrix to also setting a material for each object that bad? I vaguely remember reading somewhere that each time you change something in the pipeline, it has to get flushed and that can cause performance issues. But for each drawing call i'm setting up a model to world matrix anyway, so what sense does it make to ever be concerned about this? BTW is there any information about whether changing a uniform and calling glBufferSubData is more (or less) expensive.

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  • How to break out of if statement

    - by TheBroodian
    I'm not sure if the title is exactly an accurate representation of what I'm actually trying to ask, but that was the best I could think of. I am experiencing an issue with my character class. I have developed a system so that he can perform chain attacks, and something that was important to me was that 1)button presses during the process of an attack wouldn't interrupt the character, and 2) at the same time, button presses should be stored so that the player can smoothly queue up chain attacks in the middle of one so that gameplay doesn't feel rigid or unresponsive. This all begins when the player presses the punch button. Upon pressing the punch button, the game checks the state of the dpad at the moment of the button press, and then translates the resulting combined buttons into an int which I use as an enumerator relating to a punch method for the character. The enumerator is placed into a List so that the next time the character's Update() method is called, it will execute the next punch in the list. It only executes the next punch if my character is flagged with acceptInput as true. All attacks flag acceptInput as false, to prevent the interruption of attacks, and then at the end of an attack, acceptInput is set back to true. While accepting input, all other actions are polled for, i.e. jumping, running, etc. In runtime, if I attack, and then queue up another attack behind it (by pressing forward+punch) I can see the second attack visibly execute, which should flag acceptInput as false, yet it gets interrupted and my character will stop punching and start running if I am still holding down the dpad. Included is some code for context. This is the input region for my character. //Placed this outside the if (acceptInput) tree because I want it //to be taken into account whether we are accepting input or not. //This will queue up attacks, which will only be executed if we are accepting input. //This creates a desired effect that helps control the character in a // smoother fashion for the player. if (Input.justPressed(buttonManager.Punch)) { int dpadPressed = Input.DpadState(0); if (attackBuffer.Count() < 1) { attackBuffer.Add(CheckPunch(dpadPressed)); } else { attackBuffer.Clear(); attackBuffer.Add(CheckPunch(dpadPressed)); } } if (acceptInput) { if (attackBuffer.Count() > 0) { ExecutePunch(attackBuffer[0]); attackBuffer.RemoveAt(0); } //If D-Pad left is being held down. if (Input.DpadDirectionHeld(0, buttonManager.Left)) { flipped = false; if (onGround) { newAnimation = "run"; } velocity = new Vector2(velocity.X - acceleration, velocity.Y); if (walking == true && velocity.X <= -walkSpeed) { velocity.X = -walkSpeed; } else if (walking == false && velocity.X <= -maxSpeed) { velocity.X = -maxSpeed; } } //If D-Pad right is being held down. if (Input.DpadDirectionHeld(0, buttonManager.Right)) { flipped = true; if (onGround) { newAnimation = "run"; } velocity = new Vector2(velocity.X + acceleration, velocity.Y); if (walking == true && velocity.X >= walkSpeed) { velocity.X = walkSpeed; } else if (walking == false && velocity.X >= maxSpeed) { velocity.X = maxSpeed; } } //If jump/accept button is pressed. if (Input.justPressed(buttonManager.JumpAccept)) { if (onGround) { Jump(); } } //If toggle element next button is pressed. if (Input.justPressed(buttonManager.ToggleElementNext)) { if (elements.Count != 0) { elementInUse++; if (elementInUse >= elements.Count) { elementInUse = 0; } } } //If toggle element last button is pressed. if (Input.justPressed(buttonManager.ToggleElementLast)) { if (elements.Count != 0) { elementInUse--; if (elementInUse < 0) { elementInUse = Convert.ToSByte(elements.Count() - 1); } } } //If character is in the process of jumping. if (jumping == true) { if (Input.heldDown(buttonManager.JumpAccept)) { velocity.Y -= fallSpeed.Y; maxJumpTime -= elapsed; } if (Input.justReleased(buttonManager.JumpAccept) || maxJumpTime <= 0) { jumping = false; maxJumpTime = 0; } } //Won't execute abilities if input isn't being accepted. foreach (PlayerAbility ability in playerAbilities) { if (buffer.Matches(ability)) { if (onGround) { ability.Activate(); } if (!onGround && ability.UsableInAir) { ability.Activate(); } else if (!onGround && !ability.UsableInAir) { buffer.Clear(); } } } } When the attackBuffer calls ExecutePunch(int) method, ExecutePunch() will call one of the following methods: private void NeutralPunch1() //0 { acceptInput = false; busy = true; newAnimation = "punch1"; numberOfAttacks++; timeSinceLastAttack = 0; } private void ForwardPunch2(bool toLeft) //true == 7, false == 4 { forwardPunch2Timer = 0f; acceptInput = false; busy = true; newAnimation = "punch2begin"; numberOfAttacks++; timeSinceLastAttack = 0; if (toLeft) { velocity.X -= 800; } if (!toLeft) { velocity.X += 800; } } I assume the attack is being interrupted due to the fact that ExecutePunch() is in the same if statement as running, but I haven't been able to find a suitable way to stop this happening. Thank you ahead of time for reading this, I apologize for it having become so long winded.

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  • Change collision action

    - by PatrickR
    I have a collision detection and its working fine, the problem is, that whenever my "bird" is hitting a "cloud", the cloud dissapers and i get some points. The same happens for the "sol" which it should, but not with the clouds. How can this be changed ? ive tryed a lot, but can seem to figger it out. Collision Code - (void)update:(ccTime)dt { bird.position = ccpAdd(bird.position, skyVelocity); NSMutableArray *projectilesToDelete = [[NSMutableArray alloc] init]; for (CCSprite *bird in _projectiles) { bird.anchorPoint = ccp(0, 0); CGRect absoluteBox = CGRectMake(bird.position.x, bird.position.y, [bird boundingBox].size.width, [bird boundingBox].size.height); NSMutableArray *targetsToDelete = [[NSMutableArray alloc] init]; for (CCSprite *cloudSprite in _targets) { cloudSprite.anchorPoint = ccp(0, 0); CGRect absoluteBox = CGRectMake(cloudSprite.position.x, cloudSprite.position.y, [cloudSprite boundingBox].size.width, [cloudSprite boundingBox].size.height); if (CGRectIntersectsRect([bird boundingBox], [cloudSprite boundingBox])) { [targetsToDelete addObject:cloudSprite]; } } for (CCSprite *solSprite in _targets) { solSprite.anchorPoint = ccp(0, 0); CGRect absoluteBox = CGRectMake(solSprite.position.x, solSprite.position.y, [solSprite boundingBox].size.width, [solSprite boundingBox].size.height); if (CGRectIntersectsRect([bird boundingBox], [solSprite boundingBox])) { [targetsToDelete addObject:solSprite]; score += 50/2; [scoreLabel setString:[NSString stringWithFormat:@"%d", score]]; } } // NÅR SKYEN BLIVER RAMT AF FUGLEN for (CCSprite *cloudSprite in targetsToDelete) { //[_targets removeObject:cloudSprite]; //[self removeChild:cloudSprite cleanup:YES]; } // NÅR SOLEN BLIVER RAMT AF FUGLEN for (CCSprite *solSprite in targetsToDelete) { [_targets removeObject:solSprite]; [self removeChild:solSprite cleanup:YES]; } if (targetsToDelete.count > 0) { [projectilesToDelete addObject:bird]; } [targetsToDelete release]; } // NÅR FUGLEN BLIVER RAMT AF ALT ANDET for (CCSprite *bird in projectilesToDelete) { //[_projectiles removeObject:bird]; //[self removeChild:bird cleanup:YES]; } [projectilesToDelete release]; }

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  • Trouble with AABB collision response and physics

    - by WCM
    I have been racking my brain trying to figure out a problem I am having with physics and basic AABB collision response. I am fairly close as the physics are mostly right. Gravity feels good and movement is solid. The issue I am running into is that when I land on the test block in my project, I can jump off of it most of the time. If I repeatedly jump in place, I will eventually get stuck one or two pixels below the surface of the test block. If I try to jump, I can become free of the other block, but it will happen again a few jumps later. I feel like I am missing something really obvious with this. I have two functions that support the detection and function to return a vector for the overlap of the two rectangle bounding boxes. I have a single update method that is processing the physics and collision for the entity. I feel like I am missing something very simple, like an ordering of the physics vs. collision response handling. Any thoughts or help can be appreciated. I apologize for the format of the code, tis prototype code mostly. The collision detection function: public static bool Collides(Rectangle source, Rectangle target) { if (source.Right < target.Left || source.Bottom < target.Top || source.Left > target.Right || source.Top > target.Bottom) { return false; } return true; } The overlap function: public static Vector2 GetMinimumTranslation(Rectangle source, Rectangle target) { Vector2 mtd = new Vector2(); Vector2 amin = source.Min(); Vector2 amax = source.Max(); Vector2 bmin = target.Min(); Vector2 bmax = target.Max(); float left = (bmin.X - amax.X); float right = (bmax.X - amin.X); float top = (bmin.Y - amax.Y); float bottom = (bmax.Y - amin.Y); if (left > 0 || right < 0) return Vector2.Zero; if (top > 0 || bottom < 0) return Vector2.Zero; if (Math.Abs(left) < right) mtd.X = left; else mtd.X = right; if (Math.Abs(top) < bottom) mtd.Y = top; else mtd.Y = bottom; // 0 the axis with the largest mtd value. if (Math.Abs(mtd.X) < Math.Abs(mtd.Y)) mtd.Y = 0; else mtd.X = 0; return mtd; } The update routine (gravity = 0.001f, jumpHeight = 0.35f, moveAmount = 0.15f): public void Update(GameTime gameTime) { Acceleration.Y = gravity; Position += new Vector2((float)(movement * moveAmount * gameTime.ElapsedGameTime.TotalMilliseconds), (float)(Velocity.Y * gameTime.ElapsedGameTime.TotalMilliseconds)); Velocity.Y += Acceleration.Y; Vector2 previousPosition = new Vector2((int)Position.X, (int)Position.Y); KeyboardState keyboard = Keyboard.GetState(); movement = 0; if (keyboard.IsKeyDown(Keys.Left)) { movement -= 1; } if (keyboard.IsKeyDown(Keys.Right)) { movement += 1; } if (Position.Y + 16 > GameClass.Instance.GraphicsDevice.Viewport.Height) { Velocity.Y = 0; Position = new Vector2(Position.X, GameClass.Instance.GraphicsDevice.Viewport.Height - 16); IsOnSurface = true; } if (Collision.Collides(BoundingBox, GameClass.Instance.block.BoundingBox)) { Vector2 mtd = Collision.GetMinimumTranslation(BoundingBox, GameClass.Instance.block.BoundingBox); Position += mtd; Velocity.Y = 0; IsOnSurface = true; } if (keyboard.IsKeyDown(Keys.Space) && !previousKeyboard.IsKeyDown(Keys.Space)) { if (IsOnSurface) { Velocity.Y = -jumpHeight; IsOnSurface = false; } } previousKeyboard = keyboard; } This is also a full download to the project. https://www.box.com/s/3rkdtbso3xgfgc2asawy P.S. I know that I could do this with the XNA Platformer Starter Kit algo, but it has some deep flaws that I am going to try to live without. I'd rather go the route of collision response via an overlay function. Thanks for any and all insight!

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  • How to make room reflection using Cubemap

    - by MaT
    I am trying to use a cube map of the inside of a room to create some reflections on walls, ceiling and floor. But when I use the cube map, the reflected image is not correct. The point of view seems to be false. To be correct I use a different cube map for each walls, floor or ceiling. The cube map is calculated from the center of the plane looking at the room. Are there specialized techniques to achieve such effect ? Thanks a lot !

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  • How to cover the widest range of computers when publishing?

    - by DevilWithin
    When you plan a game, or even when you already made a game, and its time to publish, you wonder how much of your audience is covered by the game technology demands. I'm directing this essentialy to casual games, as I constantly see people having old laptops and being unable to replace them. Laptops with integrated cards whose OpenGL version doesn't even support textures larger than 1024x1024. These people may be avid gamers as well, and a reasonable share of the audience to consider giving them the chance to play casual games, once they cannot play any blockbusters. As I've seen happening, a very "noticeable" example is Angry Birds. It's gameplay is merely casual (I think nobody disagrees here) and still, it uses so high resolution textures that at least OpenGL 2.0 or around is needed, which blocks away a lot of people. So, the actual question is: what is a good tradeoff for this issue? Would it be better to just sacrifice the texture resolution for everyone, but have more supported hardware? Would it be better to keep the high quality and just slice the textures into smaller ones, sacrificing the performance a little bit? What else? Any ideas about this topic are welcome for discussion.

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  • 2D Animation Smoothness - Delta time vs. Kinematics

    - by viperld002
    I'm animating a sprite in 2D with key frames of rotation and xy-positions. I've recently had a discussion with someone saying that when the device (happens to be an iPad using cocos2D) hits a performance bump due to whatever else the user may be doing, lag will arise and that the best way to fight it is to not use actual positions, but velocities, accelerations and torques with kinematics. His message is to evaluate the positions and rotations from these speeds at the current point in time. I've never experienced a situation where I've heard of using kinematics to stem lag in 2D animations and am not sure of how effective it could be. Also, it seems to be overkill. The application is not networked so it's all running on a local device. The desired effect is that the animation always plays as closely as it can to the target frame rate. Wouldn't the technique suffer the same problems as just using the time since the last frame or a fixed time step since the kinematics would also require some time value to perform the calculation? What techniques could you suggest to best achieve the desired effect? EDIT 1 Thank you for your responses, they are very illuminating. I want to clarify my question before choosing an answer however, to make sure that this post really serves it's purpose. I have a sprite of a ball, and a text file with 3 arrays worth of information (rotation,translations x, translations y) with each unit of information existing as a key frame to be stepped through (0 to 49 and back to 0 to replay it again). I have this playing by interpolating from the current key frame to the next, every n-units of time. The animation is visibly correct when compared to a video I was given of it, and it is smooth because of the interpolations between the key frames. This is the existing state of the project. There are no physics simulated, only a static animation of a ball moving in a way an artist specifically designed. Should I, instead of rotation in degrees and translations by positions in space, derive velocities, accelerations and torques to express this static animation as a function of time? As in, position now = foo(time now), where foo uses kinematics.

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  • Behaviour tree code example?

    - by jokoon
    http://altdevblogaday.org/2011/02/24/introduction-to-behavior-trees/ Obviously the most interesting article I found on this website. What do you think about it ? It lacks some code example, don't you know any ? I also read that state machines are not very flexible compared to behaviour trees... On top of that I'm not sure if there is a true link between state machines and the state pattern... is there ?

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  • Victory rewards in digital CCG

    - by Nils Munch
    I am currently polishing a digital CCG where people can play against friend and random opponents in a classical Magic the Gathering-like duel CCG. I plan to award the players with 20 ingame currency units (lets call them gold) for each hour they are playing, 50 for each day they are playing and X for each victory. Now, the X is what I am trying to calculate here, since I would prefer keeping the currency to a certain value, but also with to entice the players to battle. I could go with a solid figure, say 25, for beating up an opponent. But that would result in experienced players only beating up newly started players, making the experience lame for both. I could also make a laddered tier, where you start at level 1, and raise in level as you defeat your opponents, where winning over a player awards you his level x 2 in gold. Which would you prefer if you were playing a game like this. There is no gold-based scoreboard, but the gold is used to purchase new cards along the way.

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  • Is there a way to use the facebook sdk with libgdx?

    - by Rudy_TM
    I have tried to use the facebook sdk in libgdx with callbacks, but it never enters the authetication listeners, so the user never is logged in, it permits the authorization for the facebook app but it never implements the authentication interfaces :( Is there a way to use it? public MyFbClass() { facebook = new Facebook(APPID); mAsyncRunner = new AsyncFacebookRunner(facebook); SessionStore.restore(facebook, this); FB.init(this, 0, facebook, this.permissions); } ///Method for init the permissions and my listener for authetication public void init(final Activity activity, final Facebook fb,final String[] permissions) { mActivity = activity; this.fb = fb; mPermissions = permissions; mHandler = new Handler(); async = new AsyncFacebookRunner(mFb); params = new Bundle(); SessionEvents.addAuthListener(auth); } ///I call the authetication process, I call it with a callback from libgdx public void facebookAction() { // TODO Auto-generated method stub fb.authenticate(); } ///It only allow the app permission, it doesnt register the events public void authenticate() { if (mFb.isSessionValid()) { SessionEvents.onLogoutBegin(); AsyncFacebookRunner asyncRunner = new AsyncFacebookRunner(mFb); asyncRunner.logout(getContext(), new LogoutRequestListener()); //SessionStore.save(this.mFb, getContext()); } else { mFb.authorize(mActivity, mPermissions,0 , new DialogListener()); } } public class SessionListener implements AuthListener, LogoutListener { @Override public void onAuthSucceed() { SessionStore.save(mFb, getContext()); } @Override public void onAuthFail(String error) { } @Override public void onLogoutBegin() { } @Override public void onLogoutFinish() { SessionStore.clear(getContext()); } } DialogListener() { @Override public void onComplete(Bundle values) { SessionEvents.onLoginSuccess(); } @Override public void onFacebookError(FacebookError error) { SessionEvents.onLoginError(error.getMessage()); } @Override public void onError(DialogError error) { SessionEvents.onLoginError(error.getMessage()); } @Override public void onCancel() { SessionEvents.onLoginError("Action Canceled"); } }

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  • 2-d lighting day/night cycle

    - by Richard
    Off the back of this post in which I asked two questions and received one answer, which I accepted as a valid answer. I have decided to re-ask the outstanding question. I have implemented light points with shadow casting as shown here but I would like an overall map light with no point/light source. The map setup is a top-down 2-d 50X50 pixel grid. How would I go about implementing a day/night cycle lighting across a map?

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  • How to modify VBO data

    - by Romeo
    I am learning LWJGL so i can start working on my game. In order to learn LWJGL I got the idea to implement the map builder so I can get comfortable with graphics programming. Now, for the map creation tool I need to draw new elements or draw the old one's with different coordinates. Let me explain this: My game will be a 2D scroller. The map will be consisting of multiple rectangles ( 2 strip triangles). When I click my left-mouse button i want to start the rectangle and when I release it I want to stop the rectangle bottom-right at that position. As I want to use VBOs I want to know how to modify data inside the VBO based on user input. Should i have a copy of a vertex array and then add the whole array to the VBO at each user input? How is usually implemented the VBO update?

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  • Android Bitmap : collision Detecting [on hold]

    - by user2505374
    I am writing an Android game right now and I would need some help in the collision of the wall on screen. When I drag the ball in the top and right it able to collide in wall but when I drag it faster it was able to overlap in the wall. public boolean onTouchEvent(MotionEvent event) { int x = (int) event.getX(); int y = (int) event.getY(); switch (event.getAction()) { // if the player moves case MotionEvent.ACTION_MOVE: { if (playerTouchRect.contains(x, y)) { boolean left = false; boolean right = false; boolean up = false; boolean down = false; boolean canMove = false; boolean foundFinish = false; if (x != pLastXPos) { if (x < pLastXPos) { left = true; } else { right = true; } pLastXPos = x; } if (y != pLastYPos) { if (y < pLastYPos) { up = true; } else { down = true; } pLastYPos = y; } plCellRect = getRectFromPos(x, y); newplRect.set(playerRect); newplRect.left = x - (int) (playerRect.width() / 2); newplRect.right = x + (int) (playerRect.width() / 2); newplRect.top = y - (int) (playerRect.height() / 2); newplRect.bottom = y + (int) (playerRect.height() / 2); int currentRow = 0; int currentCol = 0; currentRow = getRowFromYPos(newplRect.top); currentCol = getColFromXPos(newplRect.right); if(!canMove){ canMove = mapManager.getCurrentTile().pMaze[currentRow][currentCol] == Cell.wall; canMove =true; } finishTest = mapManager.getCurrentTile().pMaze[currentRow][currentCol]; foundA = finishTest == Cell.valueOf(letterNotGet + ""); canMove = mapManager.getCurrentTile().pMaze[currentRow][currentCol] != Cell.wall; canMove = (finishTest == Cell.floor || finishTest == Cell.pl) && canMove; if (canMove) { invalidate(); setTitle(); } if (foundA) { mapManager.getCurrentTile().pMaze[currentRow][currentCol] = Cell.floor; // finishTest letterGotten.add(letterNotGet); playCurrentLetter(); /*sounds.play(sExplosion, 1.0f, 1.0f, 0, 0, 1.5f);*/ foundS = letterNotGet == 's'; letterNotGet++; }if(foundS){ AlertDialog.Builder builder = new AlertDialog.Builder(mainActivity); builder.setTitle(mainActivity.getText(R.string.finished_title)); LayoutInflater inflater = mainActivity.getLayoutInflater(); View view = inflater.inflate(R.layout.finish, null); builder.setView(view); View closeButton =view.findViewById(R.id.closeGame); closeButton.setOnClickListener(new OnClickListener() { @Override public void onClick(View clicked) { if(clicked.getId() == R.id.closeGame) { mainActivity.finish(); } } }); AlertDialog finishDialog = builder.create(); finishDialog.show(); } else { Log.d(TAG, "INFO: updated player position"); playerRect.set(newplRect); setTouchZone(); updatePlayerCell(); } } // end of (CASE) if playerTouch break; } // end of (SWITCH) Case motion }//end of Switch return true; }//end of TouchEvent private void finish() { // TODO Auto-generated method stub } public int getColFromXPos(int xPos) { val = xPos / (pvWidth / mapManager.getCurrentTile().pCols); if (val == mapManager.getCurrentTile().pCols) { val = mapManager.getCurrentTile().pCols - 1; } return val; } /** * Given a y pixel position, return the row of the cell it is in This is * used when determining the type of adjacent Cells. * * @param yPos * y position in pixels * @return The cell this position is in */ public int getRowFromYPos(int yPos) { val = yPos / (pvHeight / mapManager.getCurrentTile().pRows); if (val == mapManager.getCurrentTile().pRows) { val = mapManager.getCurrentTile().pRows - 1; } return val; } /** * When preserving the position we need to know which cell the player is in, * so calculate it from the centre on its Rect */ public void updatePlayerCell() { plCell.x = (playerRect.left + (playerRect.width() / 2)) / (pvWidth / mapManager.getCurrentTile().pCols); plCell.y = (playerRect.top + (playerRect.height() / 2)) / (pvHeight / mapManager.getCurrentTile().pRows); if (mapManager.getCurrentTile().pMaze[plCell.y][plCell.x] == Cell.floor) { for (int row = 0; row < mapManager.getCurrentTile().pRows; row++) { for (int col = 0; col < mapManager.getCurrentTile().pCols; col++) { if (mapManager.getCurrentTile().pMaze[row][col] == Cell.pl) { mapManager.getCurrentTile().pMaze[row][col] = Cell.floor; break; } } } mapManager.getCurrentTile().pMaze[plCell.y][plCell.x] = Cell.pl; } } public Rect getRectFromPos(int x, int y) { calcCell.left = ((x / cellWidth) + 0) * cellWidth; calcCell.right = calcCell.left + cellWidth; calcCell.top = ((y / cellHeight) + 0) * cellHeight; calcCell.bottom = calcCell.top + cellHeight; Log.d(TAG, "Rect: " + calcCell + " Player: " + playerRect); return calcCell; } public void setPlayerRect(Rect newplRect) { playerRect.set(newplRect); } private void setTouchZone() { playerTouchRect.set( playerRect.left - playerRect.width() / TOUCH_ZONE, playerRect.top - playerRect.height() / TOUCH_ZONE, playerRect.right + playerRect.width() / TOUCH_ZONE, playerRect.bottom + playerRect.height() / TOUCH_ZONE); } public Rect getPlayerRect() { return playerRect; } public Point getPlayerCell() { return plCell; } public void setPlayerCell(Point cell) { plCell = cell; }

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