Search Results

Search found 32277 results on 1292 pages for 'module development'.

Page 471/1292 | < Previous Page | 467 468 469 470 471 472 473 474 475 476 477 478  | Next Page >

• How can I solve this SAT edge case?

  - by ssb

  I have an SAT implementation that basically works, and the fact that it works is what's giving me a few headaches. Basically there are some situations where using the SAT doesn't quite give me my intended result. One of these involves movement across multiple collision objects. Or to put it another way, if I have several collision boxes lined up next to each other such as to create something like a wall or a floor, movement along that surface while constantly applying force into that surface sometimes causes hangups, i.e. the player stops moving. This illustration shows what I mean: The 2 boxes on the bottom represent a floor, and the box on top/in the middle represents what my player is doing. There are several squares lined up as world obstacles to create some kind of wall, and if I move to the left across this surface while holding the down key then the issue arises. It only happens at the exact dividing point between two blocks. It only happens when moving to the left. At any rate I think I know why it happens, but I don't know how to solve it. Basically when I update my player movement I consider which directions are pressed, naturally, so if down is pressed I will add the speed to the Y component, and so on. But due to the way my SAT is implemented, when the penetration into the shape is the same from both sides it just goes with the smallest axis that it finds first, and it checks collisions against objects in the order that they were created because it goes through a foreach loop on the list of collidable objects. So this all adds up to the effect of if I'm moving to the left over a series of boxes while holding down, it will resolve me back to the right out of the first box and then up out of the box to the right of it, and this continues as long as the penetration is the same. The odd part is that this doesn't happen every time, which I am going to attribute to some oddity regarding multiplying velocity by the game time and causing some minor discrepancies between the lengths. Ultimately what this boils down to is that it will keep resolving me to the right and up, but this is technically expected behavior. All the solutions I can think of only address the symptoms of this problem and not the actual cause, such as not using many blocks to create walls or shapes, which is an option I'd like to keep open. I could also change which axis my algorithm defaults to, but that would just cause problems when going up/down along the walls. What can I do to fix this?

  Read the article

• TileMapRenderer in libGDX not drawing anything

  - by Benjamin Dengler

  So I followed the tutorial on the libGDX wiki to draw Tiled maps but it doesn't seem to render anything. Here's how I setup my OrthographicCamera and load the map: camera = new OrthographicCamera(Gdx.graphics.getWidth(), Gdx.graphics.getHeight()); map = TiledLoader.createMap(Gdx.files.internal("maps/test.tmx")); atlas = new TileAtlas(map, Gdx.files.internal("maps")); tileMapRenderer = new TileMapRenderer(map, atlas, 8, 8); And here is my render function: Gdx.gl.glClearColor(0, 0, 0, 1); Gdx.gl.glClear(GL10.GL_COLOR_BUFFER_BIT); camera.update(); tileMapRenderer.render(camera); Also I did pack the tile map using the TiledMapPacker. I'm completely stumped... am I missing anything obvious here? EDIT: While debugging I noticed that the TileAtlas seems to be empty, which I guess shouldn't be the case, but I have no idea why it's empty.

  Read the article

• Friction not working for Vehicle in BulletPhysics

  - by Manmohan Bishnoi

  I am creating a vehicle using bullet-physics engine (v 2.82). I created a ground ( btBoxShape ), a box and a vehicle (following the demo). But friction between ground and vehicle wheels seems not working. As soon as the vehicle is placed in 3d world, it starts moving forward. START : Steering works for the vehicle, but engineForce and brakingForce does not work (i.e. I cannot speed-up or stop the vehicle) : I create physics world like this : void initPhysics() { broadphase = new btDbvtBroadphase(); collisionConfiguration = new btDefaultCollisionConfiguration(); dispatcher = new btCollisionDispatcher(collisionConfiguration); solver = new btSequentialImpulseConstraintSolver(); dynamicsWorld = new btDiscreteDynamicsWorld(dispatcher, broadphase, solver, collisionConfiguration); dynamicsWorld->setGravity(btVector3(0, -9.81, 0)); // Debug Drawer bulletDebugugger.setDebugMode(btIDebugDraw::DBG_DrawWireframe); dynamicsWorld->setDebugDrawer(&bulletDebugugger); //groundShape = new btStaticPlaneShape(btVector3(0, 1, 0), 1); groundShape = new btBoxShape(btVector3(50, 3, 50)); fallShape = new btBoxShape(btVector3(1, 1, 1)); // Orientation and Position of Ground groundMotionState = new btDefaultMotionState(btTransform(btQuaternion(0, 0, 0, 1), btVector3(0, -3, 0))); btRigidBody::btRigidBodyConstructionInfo groundRigidBodyCI(0, groundMotionState, groundShape, btVector3(0, 0, 0)); groundRigidBody = new btRigidBody(groundRigidBodyCI); dynamicsWorld->addRigidBody(groundRigidBody); /////////////////////////////////////////////////////////////////////// // Vehicle Setup /////////////////////////////////////////////////////////////////////// vehicleChassisShape = new btBoxShape(btVector3(1.f, 0.5f, 2.f)); vehicleBody = new btCompoundShape(); localTrans.setIdentity(); localTrans.setOrigin(btVector3(0, 1, 0)); vehicleBody->addChildShape(localTrans, vehicleChassisShape); localTrans.setOrigin(btVector3(3, 0.f, 0)); vehicleMotionState = new btDefaultMotionState(localTrans); //vehicleMotionState = new btDefaultMotionState(btTransform(btQuaternion(0, 0, 0, 1), btVector3(3, 0, 0))); btVector3 vehicleInertia(0, 0, 0); vehicleBody->calculateLocalInertia(vehicleMass, vehicleInertia); btRigidBody::btRigidBodyConstructionInfo vehicleRigidBodyCI(vehicleMass, vehicleMotionState, vehicleBody, vehicleInertia); vehicleRigidBody = new btRigidBody(vehicleRigidBodyCI); dynamicsWorld->addRigidBody(vehicleRigidBody); wheelShape = new btCylinderShapeX(btVector3(wheelWidth, wheelRadius, wheelRadius)); { vehicleRayCaster = new btDefaultVehicleRaycaster(dynamicsWorld); vehicle = new btRaycastVehicle(vehicleTuning, vehicleRigidBody, vehicleRayCaster); // never deactivate vehicle vehicleRigidBody->setActivationState(DISABLE_DEACTIVATION); dynamicsWorld->addVehicle(vehicle); float connectionHeight = 1.2f; bool isFrontWheel = true; vehicle->setCoordinateSystem(rightIndex, upIndex, forwardIndex); // 0, 1, 2 // add wheels // front left btVector3 connectionPointCS0(CUBE_HALF_EXTENT-(0.3*wheelWidth), connectionHeight, 2*CUBE_HALF_EXTENT-wheelRadius); vehicle->addWheel(connectionPointCS0, wheelDirectionCS0, wheelAxleCS, suspensionRestLength, wheelRadius, vehicleTuning, isFrontWheel); // front right connectionPointCS0 = btVector3(-CUBE_HALF_EXTENT+(0.3*wheelWidth), connectionHeight, 2*CUBE_HALF_EXTENT-wheelRadius); vehicle->addWheel(connectionPointCS0, wheelDirectionCS0, wheelAxleCS, suspensionRestLength, wheelRadius, vehicleTuning, isFrontWheel); isFrontWheel = false; // rear right connectionPointCS0 = btVector3(-CUBE_HALF_EXTENT+(0.3*wheelWidth), connectionHeight, -2*CUBE_HALF_EXTENT+wheelRadius); vehicle->addWheel(connectionPointCS0, wheelDirectionCS0, wheelAxleCS, suspensionRestLength, wheelRadius, vehicleTuning, isFrontWheel); // rear left connectionPointCS0 = btVector3(CUBE_HALF_EXTENT-(0.3*wheelWidth), connectionHeight, -2*CUBE_HALF_EXTENT+wheelRadius); vehicle->addWheel(connectionPointCS0, wheelDirectionCS0, wheelAxleCS, suspensionRestLength, wheelRadius, vehicleTuning, isFrontWheel); for (int i = 0; i < vehicle->getNumWheels(); i++) { btWheelInfo& wheel = vehicle->getWheelInfo(i); wheel.m_suspensionStiffness = suspensionStiffness; wheel.m_wheelsDampingRelaxation = suspensionDamping; wheel.m_wheelsDampingCompression = suspensionCompression; wheel.m_frictionSlip = wheelFriction; wheel.m_rollInfluence = rollInfluence; } } /////////////////////////////////////////////////////////////////////// // Orientation and Position of Falling body fallMotionState = new btDefaultMotionState(btTransform(btQuaternion(0, 0, 0, 1), btVector3(-1, 5, 0))); btScalar mass = 1; btVector3 fallInertia(0, 0, 0); fallShape->calculateLocalInertia(mass, fallInertia); btRigidBody::btRigidBodyConstructionInfo fallRigidBodyCI(mass, fallMotionState, fallShape, fallInertia); fallRigidBody = new btRigidBody(fallRigidBodyCI); dynamicsWorld->addRigidBody(fallRigidBody); } I step physics world like this : // does not work vehicle->applyEngineForce(maxEngineForce, WHEEL_REARLEFT); vehicle->applyEngineForce(maxEngineForce, WHEEL_REARRIGHT); // these also do not work vehicle->setBrake(gBreakingForce, WHEEL_REARLEFT); vehicle->setBrake(gBreakingForce, WHEEL_REARRIGHT); // this works vehicle->setSteeringValue(gVehicleSteering, WHEEL_FRONTLEFT); vehicle->setSteeringValue(gVehicleSteering, WHEEL_FRONTRIGHT); dynamicsWorld->stepSimulation(1 / 60.0f, 10); However If I apply brakingForce to all 4 wheels (i.e. including WHEEL_FRONTLEFT and WHEEL_FRONTRIGHT), then my vehicle stops, but keeps sliding/moving forward very very slowly. How do I fix this ?

  Read the article

• What's a good way to programmatically manage a cloneable entity?

  - by bobobobo

  Say you have missiles or rockets that a player can fire. What's a good way to programmatically manage the cloning of a base rocket, for example? I can think of 2 ways to do it: Player has a currently selected weapon (which is an int) When player shoots, the selectedWeapon member is looked at, and the correct instance of rocket is created (with some base parameters) Or Player has a currently selected weapon (which is a pointer, to a "base instance" of the rocket object) When player shoots, the base instance rocket is cloned, transformed, and shot into the game world

  Read the article

• Managing flash animations for a game

  - by LoveMeSomeCode

  Ok, I've been writing C# for a while, but I'm new to ActionScript, so this is a question about best practices. We're developing a simple match game, where the user selects tiles and tries to match various numbers - sort of like memory - and when the match is made we want a series of animations to take place, and when they're done, remove the tile and add a new one. So basically it's: User clicks the MC Animation 1 on the MC starts Animation 1 ends Remove the MC from the stage Add a new MC Start the animation on the new MC The problem I run into is that I don't want to make the same timeline motion tween on each and every tile, when the animation is all the same. It's just the picture in the tile that's different. The other method I've come up with is to just apply the tweens in code on the main stage. Then I attach an event handler for MOTION_FINISH, and in that handler I trigger the next animation and listen for that to finish etc. This works too, but not only do I have to do all the tweening in code, I have a seperate event handler for each stage of the animation. So is there a more structured way of chaining these animations together?

  Read the article

• Component-wise GLSL vector branching

  - by Gustavo Maciel

  I'm aware that it usually is a BAD idea to operate separately on GLSL vec's components separately. For example: //use instrinsic functions, they do the calculation on 4 components at a time. float dot = v1.x*v2.x + v1.y * v2.y + v1.z * v2.z; //NEVER float dot = dot(v1, v2); //YES //Multiply one by one is not good too, since the ALU can do the 4 components at a time too. vec3 mul = vec3(v1.x * v2.x, v1.y * v2.y, v1.z * v2.z); //NEVER vec3 mul = v1 * v2; I've been struggling thinking, are there equivalent operations for branching? For example: vec4 Overlay(vec4 v1, vec4 v2, vec4 opacity) { bvec4 less = lessThan(v1, vec4(0.5)); vec4 blend; for(int i = 0; i < 4; ++i) { if(less[i]) blend[i] = 2.0 * v1[i]*v2[i]; else blend[i] = 1.0 - 2.0 * (1.0 - v1[i])*(1.0 - v2[i]); } return v1 + (blend-v1)*opacity; } This is a Overlay operator that works component wise. I'm not sure if this is the best way to do it, since I'm afraid these for and if can be a bottleneck later. Tl;dr, Can I branch component wise? If yes, how can I optimize that Overlay function with it?

  Read the article

• What's the proper way to calculate probability for a card game?

  - by Milan Babuškov

  I'm creating AI for a card game, and I run into problem calculating the probability of passing/failing the hand when AI needs to start the hand. Cards are A, K, Q, J, 10, 9, 8, 7 (with A being the strongest) and AI needs to play to not take the hand. Assuming there are 4 cards of the suit left in the game and one is in AI's hand, I need to calculate probability that one of the other players would take the hand. Here's an example: AI player has: J Other 2 players have: A, K, 7 If a single opponent has AK7 then AI would lose. However, if one of the players has A or K without 7, AI would survive. Now, looking at possible distribution, I have: P1 P2 AI --- --- --- AK7 loses AK 7 survives A7 K survives K7 A survives A 7K survives K 7A survives 7 KA survives AK7 loses Looking at this, it seems that there is 75% chance of survival. However, I skipped the permutations that mirror the ones from above. It should be the same, but somehow when I write them all down, it seems that chance is only 50%: P1 P2 AI --- --- --- AK7 loses A7K loses K7A loses KA7 loses 7AK loses 7KA loses AK 7 survives A7 K survives K7 A survives KA 7 survives 7A K survives 7K A survives A K7 survives A 7K survives K 7A survives K A7 survives 7 AK survives 7 KA survives AK7 loses A7K loses K7A loses KA7 loses 7AK loses 7KA loses 12 loses, 12 survivals = 50% chance. Obviously, it should be the same (shouldn't it?) and I'm missing something in one of the ways to calculate. Which one is correct?

  Read the article

• Developing an ELO like point system for a multiplayer gaming site

  - by Alejandro Piad

  I'm currently working on a gaming site where users will submit virtual players for different games, like Chess, Nash, Backgammon, Go, etc. The idea is that users don't compete themselves, but through their virtual players. There will be leagues, tournaments, and other competition formats. The question is which would be a good rating system for users in this environment. Take into account that every user may have many different virtual players playing in many different games. As a general guideline I would like to guarantee the following properties: Users who have a lot of mediocre players should not score higher than users with a few very good players. A user with a high rating should not be penalized if he adds a new bad player, until he has had enough time to improve his player. Users who don't play often should not score higher than users who play every day. Thanks in advance.

  Read the article

• DirectWrite Producing Strange Artifacts?

  - by smoth190

  I've written the basis to my UI system around Direct2D. I like it because it's fast and easy to use (even if I had to do some messy work to get it to work with DirectX11). However, I notice when using DirectWrite I'm getting strange problems with my text. As you can see, the e is a little screwwed up, and it overall looks a little bumpy. This only happens with certain fonts in certain sizes, and with certain arrangements of letters. This particular example is Verdana in size 16.0 font. Can I fix this? It's pretty annoying to change all my words and fonts because of this problem.

  Read the article

• Need ideas for an algorithm to draw irregular blotchy shapes

  - by Yttermayn

  I'm looking to draw irregular shapes on an x,y grid, and I'd like to come up with a simple, fast method if possible. My only idea so far is to draw a bunch of circles of random sizes very near each other, but at a random distance apart from a more or less central coordinate, then fill in any blank spaces. I realize this is a clunky, inelegant method, hopefully it will give you a rough idea of the kinds of rounded, random blotchy shapesI'm shooting for. Please suggest methods to accomplish this, I'm not so much interested in code. I can noodle that part out myself. Thanks!

  Read the article

• Tessellation Texture Coordinates

  - by Stuart Martin

  Firstly some info - I'm using DirectX 11 , C++ and I'm a fairly good programmer but new to tessellation and not a master graphics programmer. I'm currently implementing a tessellation system for a terrain model, but i have reached a snag. My current system produces a terrain model from a height map complete with multiple texture coordinates, normals, binormals and tangents for rendering. Now when i was using a simple vertex and pixel shader combination everything worked perfectly but since moving to include a hull and domain shader I'm slightly confused and getting strange results. My terrain is a high detail model but the textured results are very large patches of solid colour. My current setup passes the model data into the vertex shader then through the hull into the domain and then finally into the pixel shader for use in rendering. My only thought is that in my hull shader i pass the information into the domain shader per patch and this is producing the large areas of solid colour because each patch has identical information. Lighting and normal data are also slightly off but not as visibly as texturing. Below is a copy of my hull shader that does not work correctly because i think the way that i am passing the data through is incorrect. If anyone can help me out but suggesting an alternative way to get the required data into the pixel shader? or by showing me the correct way to handle the data in the hull shader id be very thankful! cbuffer TessellationBuffer { float tessellationAmount; float3 padding; }; struct HullInputType { float3 position : POSITION; float2 tex : TEXCOORD0; float3 normal : NORMAL; float3 tangent : TANGENT; float3 binormal : BINORMAL; float2 tex2 : TEXCOORD1; }; struct ConstantOutputType { float edges[3] : SV_TessFactor; float inside : SV_InsideTessFactor; }; struct HullOutputType { float3 position : POSITION; float2 tex : TEXCOORD0; float3 normal : NORMAL; float3 tangent : TANGENT; float3 binormal : BINORMAL; float2 tex2 : TEXCOORD1; float4 depthPosition : TEXCOORD2; }; ConstantOutputType ColorPatchConstantFunction(InputPatch<HullInputType, 3> inputPatch, uint patchId : SV_PrimitiveID) { ConstantOutputType output; output.edges[0] = tessellationAmount; output.edges[1] = tessellationAmount; output.edges[2] = tessellationAmount; output.inside = tessellationAmount; return output; } [domain("tri")] [partitioning("integer")] [outputtopology("triangle_cw")] [outputcontrolpoints(3)] [patchconstantfunc("ColorPatchConstantFunction")] HullOutputType ColorHullShader(InputPatch<HullInputType, 3> patch, uint pointId : SV_OutputControlPointID, uint patchId : SV_PrimitiveID) { HullOutputType output; output.position = patch[pointId].position; output.tex = patch[pointId].tex; output.tex2 = patch[pointId].tex2; output.normal = patch[pointId].normal; output.tangent = patch[pointId].tangent; output.binormal = patch[pointId].binormal; return output; } Edited to include the domain shader:- [domain("tri")] PixelInputType ColorDomainShader(ConstantOutputType input, float3 uvwCoord : SV_DomainLocation, const OutputPatch<HullOutputType, 3> patch) { float3 vertexPosition; PixelInputType output; // Determine the position of the new vertex. vertexPosition = uvwCoord.x * patch[0].position + uvwCoord.y * patch[1].position + uvwCoord.z * patch[2].position; output.position = mul(float4(vertexPosition, 1.0f), worldMatrix); output.position = mul(output.position, viewMatrix); output.position = mul(output.position, projectionMatrix); output.depthPosition = output.position; output.tex = patch[0].tex; output.tex2 = patch[0].tex2; output.normal = patch[0].normal; output.tangent = patch[0].tangent; output.binormal = patch[0].binormal; return output; }

  Read the article

• 2D Planet Gravity

  - by baked

  I'm trying to make a simple game where a spaceship is launched and then its path is effected by the gravity of planets. Similar to this game: http://sciencenetlinks.com/interactives/gravity.html I wish to know how to replicate the effect the planets have on the spaceship in this game so a spaceship can 'loop' around a planet to change direction. I have managed to achieve some bogus results where the spaceship loops in a huge ellipse around the planet or is only slightly affected by the gravity of a planet using Vectors. Thanks in advance. p.s I have plenty of coding experience just none to do with game dev.

  Read the article

• 3D texture coordinates for a cube

  - by Roshan

  I want to use glTexImage3D with cube. what will be the texture coordinates for it? i am using GL_TEXTURE_3D as target. I tried with u v coordinates same as 2d texture coordinates with z component 0-depth for each face. But that goes wrong. How to apply each layer to each face of the cube with target= GL_TEXTURE_3D? Lets assume i have 8 layers of 2D images in my 3D texture. I want all 8 layers to apply on each of the cube and not 1 layer on 1 face of the cube.

  Read the article

• Keeping the camera from going through walls in a first person game in Unity?

  - by Timothy Williams

  I'm using a modified version of the standard Unity First Person Controller. At the moment when I stand near walls, the camera clips through and lets me see through the wall. I know about camera occlusion and have implemented it in 3rd person games, but I have no clue how I'd accomplish this in a first person game, since the camera doesn't move from the player at all. How do other people accomplish this?

  Read the article

• Creating a newspaper that effects the game's economy?

  - by zardon

  I am writing a game in Objective C/cocos2d where a newspaper is a central part of what controls or rather effects the game's world economy as well as what a city might do (such as increase X, reduce Y) The newspaper is a bit like a "Chance card" in Monopoly, it has an effect on something. My question is, what is the best way to do write a newspaper that has both a random and specific effect within the game. Would the best strategy be to write out all the things a newspaper can affect, a PLIST of headlines (with placeholders). I think Tiny Tower uses a PLIST of events and it randomly picks an event, but I'm not sure how it actually parses it because certain events do different things. But then how do I parse all the scenarios that a newspaper can deliver? A big switch statement seems very long and complicated to do. I am wondering if there is a simpler way to handle this kind of thing. Related to this is that there might be no news that day and I'm not sure what the newspaper should display, should it just display the last headline? So, in summary. 1) A newspaper generates a headline, it affects different things, such as the world economy, prices, how city reacts 2) I need the newspaper to generate headlines (although there may be days when there are no headlines at all), but I am not sure how to parse it without using a big-ass switch statement. Thanks in advance.

  Read the article

• Narrow-phase collision detection algorithms

  - by Marian Ivanov

  There are three phases of collision detection. Broadphase: It loops between all objecs that can interact, false positives are allowed, if it would speed up the loop. Narrowphase: Determines whether they collide, and sometimes, how, no false positives Resolution: Resolves the collision. The question I'm asking is about the narrowphase. There are multiple algorithms, differing in complexity and accuracy. Hitbox intersection: This is an a-posteriori algorithm, that has the lowest complexity, but also isn't too accurate, Color intersection: Hitbox intersection for each pixel, a-posteriori, pixel-perfect, not accuratee in regards to time, higher complexity Separating axis theorem: This is used more often, accurate for triangles, however, a-posteriori, as it can't find the edge, when taking last frame in account, it's more stable Linear raycasting: A-priori algorithm, useful for semi-realistic-looking physics, finds the intersection point, even more accurate than SAT, but with more complexity Spline interpolation: A-priori, even more accurate than linear rays, even more coplexity. There are probably many more that I've forgot about. The question is, in when is it better to use SAT, when rays, when splines, and whether there is anything better.

  Read the article

• What is the best way to "carve" a terrain created from a heightmap?

  - by tigrou

  I have a 3d landscape created from a heightmap. I'd like to "carve" some holes in that terrain. That will allow me to create bridges, caverns and tunnels inside it. That operation will be done in the game editor so it doesn't need to be realtime. In the end, rendering is done using traditional polygons. What would be the best/easiest way to do that ? I already think about several solutions : Solution 1 1) Create voxels from the heightmap (very easy). In other words, fill a 3D array like this : voxels[32][32][32] from the heightmap values. 2) Carve holes in the voxels as i want (easy too). 3) Convert voxels to polygons using some iso-surface extraction technique (like marching cubes). 4) Reduce (decimate) polygons created in 3). This technique seems to be the most promising for giving good results (untested). However the problem with marching cubes is that they tends to produce lots of polygons thus reducing them is mandatory. Implementing 4) also seems not trivial, i have read several papers on the web and it seems pretty complex. I was also unable to find an example, code snippet or something to start writing an algorithm for triangle mesh decimation. Maybe there is a special decimation algorithm (simpler) for meshes created from marching cubes ? Solution 2 1) Create some triangle mesh from the heighmap (easy). 2) Apply severals 3D boolean operation (eg: subtraction with a sphere) to carve the mesh. 3) apply some procedure to reduce polygons (optional). Operation 2) seems to be very complex and to be honest i have no idea how to do that. Also applying many boolean operation seems to be slow and will maybe degrade the triangle mesh every time a boolean operation is applied.

  Read the article

• How can I test if my rotated rectangle intersects a corner?

  - by Raven Dreamer

  I have a square, tile-based collision map. To check if one of my (square) entities is colliding, I get the vertices of the 4 corners, and test those 4 points against my collision map. If none of those points are intersecting, I know I'm good to move to the new position. I'd like to allow entities to rotate. I can still calculate the 4 corners of the square, but once you factor in rotation, those 4 corners alone don't seem to be enough information to determine if the entity is trying to move to a valid state. For example: In the picture below, black is unwalkable terrain, and red is the player's hitbox. The left scenario is allowed because the 4 corners of the red square are not in the black terrain. The right scenario would also be (incorrectly) allowed, because the player, cleverly turned at a 45* angle, has its corners in valid spaces, even if it is (quite literally) cutting the corner. How can I detect scenarios similar to the situation on the right?

  Read the article

• Implementing Light Volume Front Faces

  - by cubrman

  I recently read an article about light indexed deferred rendering from here: http://code.google.com/p/lightindexed-deferredrender/ It explains its ideas in a clear way, but there was one point that I failed to understand. It in fact is one of the most interesting ones, as it explains how to implement transparency with this approach: Typically when rendering light volumes in deferred rendering, only surfaces that intersect the light volume are marked and lit. This is generally accomplished by a “shadow volume like” technique of rendering back faces – incrementing stencil where depth is greater than – then rendering front faces and only accepting when depth is less than and stencil is not zero. By only rendering front faces where depth is less than, all future lookups by fragments in the forward rendering pass will get all possible lights that could hit the fragment. Can anyone explain how exactly you need to render only front faces? Another question is why do you need the front faces at all? Why can't we simply render all the lights and store the ones that overlap at this pixel in a texture? Does this approach serves as a cut-off plane to discard lights blocked by opaque geometry?

  Read the article

• 3D Ball Physics Theory: collision response on ground and against walls?

  - by David

  I'm really struggling to get a strong grasp on how I should be handling collision response in a game engine I'm building around a 3D ball physics concept. Think Monkey Ball as an example of the type of gameplay. I am currently using sphere-to-sphere broad phase, then AABB to OBB testing (the final test I am using right now is one that checks if one of the 8 OBB points crosses the planes of the object it is testing against). This seems to work pretty well, and I am getting back: Plane that object is colliding against (with a point on the plane, the plane's normal, and the exact point of intersection. I've tried what feels like dozens of different high-level strategies for handling these collisions, without any real success. I think my biggest problem is understanding how to handle collisions against walls in the x-y axes (left/right, front/back), which I want to have elasticity, and the ground (z-axis) where I want an elastic reaction if the ball drops down, but then for it to eventually normalize and be kept "on the ground" (not go into the ground, but also not continue bouncing). Without kluging something together, I'm positive there is a good way to handle this, my theories just aren't getting me all the way there. For physics modeling and movement, I am trying to use a Euler based setup with each object maintaining a position (and destination position prior to collision detection), a velocity (which is added onto the position to determine the destination position), and an acceleration (which I use to store any player input being put on the ball, as well as gravity in the z coord). Starting from when I detect a collision, what is a good way to approach the response to get the expected behavior in all cases? Thanks in advance to anyone taking the time to assist... I am grateful for any pointers, and happy to post any additional info or code if it is useful. UPDATE Based on Steve H's and eBusiness' responses below, I have adapted my collision response to what makes a lot more sense now. It was close to right before, but I didn't have all the right pieces together at the right time! I have one problem left to solve, and that is what is causing the floor collision to hit every frame. Here's the collision response code I have now for the ball, then I'll describe the last bit I'm still struggling to understand. // if we are moving in the direction of the plane (against the normal)... if (m_velocity.dot(intersection.plane.normal) <= 0.0f) { float dampeningForce = 1.8f; // eventually create this value based on mass and acceleration // Calculate the projection velocity PVRTVec3 actingVelocity = m_velocity.project(intersection.plane.normal); m_velocity -= actingVelocity * dampeningForce; } // Clamp z-velocity to zero if we are within a certain threshold // -- NOTE: this was an experimental idea I had to solve the "jitter" bug I'll describe below float diff = 0.2f - abs(m_velocity.z); if (diff > 0.0f && diff <= 0.2f) { m_velocity.z = 0.0f; } // Take this object to its new destination position based on... // -- our pre-collision position + vector to the collision point + our new velocity after collision * time // -- remaining after the collision to finish the movement m_destPosition = m_position + intersection.diff + (m_velocity * intersection.tRemaining * GAMESTATE->dt); The above snippet is run after a collision is detected on the ball (collider) with a collidee (floor in this case). With a dampening force of 1.8f, the ball's reflected "upward" velocity will eventually be overcome by gravity, so the ball will essentially be stuck on the floor. THIS is the problem I have now... the collision code is running every frame (since the ball's z-velocity is constantly pushing it a collision with the floor below it). The ball is not technically stuck, I can move it around still, but the movement is really goofy because the velocity and position keep getting affected adversely by the above snippet. I was experimenting with an idea to clamp the z-velocity to zero if it was "close to zero", but this didn't do what I think... probably because the very next frame the ball gets a new gravity acceleration applied to its velocity regardless (which I think is good, right?). Collisions with walls are as they used to be and work very well. It's just this last bit of "stickiness" to deal with. The camera is constantly jittering up and down by extremely small fractions too when the ball is "at rest". I'll keep playing with it... I like puzzles like this, especially when I think I'm close. Any final ideas on what I could be doing wrong here? UPDATE 2 Good news - I discovered I should be subtracting the intersection.diff from the m_position (position prior to collision). The intersection.diff is my calculation of the difference in the vector of position to destPosition from the intersection point to the position. In this case, adding it was causing my ball to always go "up" just a little bit, causing the jitter. By subtracting it, and moving that clamper for the velocity.z when close to zero to being above the dot product (and changing the test from <= 0 to < 0), I now have the following: // Clamp z-velocity to zero if we are within a certain threshold float diff = 0.2f - abs(m_velocity.z); if (diff > 0.0f && diff <= 0.2f) { m_velocity.z = 0.0f; } // if we are moving in the direction of the plane (against the normal)... float dotprod = m_velocity.dot(intersection.plane.normal); if (dotprod < 0.0f) { float dampeningForce = 1.8f; // eventually create this value based on mass and acceleration? // Calculate the projection velocity PVRTVec3 actingVelocity = m_velocity.project(intersection.plane.normal); m_velocity -= actingVelocity * dampeningForce; } // Take this object to its new destination position based on... // -- our pre-collision position + vector to the collision point + our new velocity after collision * time // -- remaining after the collision to finish the movement m_destPosition = m_position - intersection.diff + (m_velocity * intersection.tRemaining * GAMESTATE->dt); UpdateWorldMatrix(m_destWorldMatrix, m_destOBB, m_destPosition, false); This is MUCH better. No jitter, and the ball now "rests" at the floor, while still bouncing off the floor and walls. The ONLY thing left is that the ball is now virtually "stuck". He can move but at a much slower rate, likely because the else of my dot product test is only letting the ball move at a rate multiplied against the tRemaining... I think this is a better solution than I had previously, but still somehow not the right idea. BTW, I'm trying to journal my progress through this problem for anyone else with a similar situation - hopefully it will serve as some help, as many similar posts have for me over the years.

  Read the article

• convert orientation vec3 to a rotation matrix

  - by lapin

  I've got a normalized vec3 that represents an orientation. Each frame of animation, an object's orientation changes slightly, so I add a delta vector to the orientation vector and then normalize to find the new orientation. I'd like to convert the vec3 that represents an orientation into a rotation matrix that I can use to orient my object. If it helps, my object is a cone, and I'd like to rotate it about the pointy end, not from its center :) PS I know I should use quaternions because of the gimbal lock problem. If someone can explain quats too, that'd be great :)

  Read the article

• Rotation based on x coordinate and x velocity?

  - by Lewis

  -(void) accelerometer:(UIAccelerometer *)accelerometer didAccelerate:(UIAcceleration *)acceleration { float deceleration = 0.3f, sensitivity = 8.0f, maxVelocity = 150; // adjust velocity based on current accelerometer acceleration playerVelocity.x = playerVelocity.x * deceleration + acceleration.x * sensitivity; // we must limit the maximum velocity of the player sprite, in both directions (positive & negative values) playerVelocity.x = fmaxf(fminf(playerVelocity.x, maxVelocity), -maxVelocity); } Hi, I want to rotate my sprite based on the velocity and accelerometer input. My sprite can move along the X axis like so: <--------- sprite ----------- But it always faces forwards, if it is moving left I want it to point slightly to the left, the degree of how far it is pointing to be judged from the velocity. This should also work for the right. I tried using atan but as the y velocity and position is always the same the function returns 0, which doesn't rotate it at all. Any ideas? Regards, Lewis.

  Read the article

• MiniMax function throws null pointer exception

  - by Sven

  I'm working on a school project, I have to build a tic tac toe game with the AI based on the MiniMax algorithm. The two player mode works like it should. I followed the code example on http://ethangunderson.com/blog/minimax-algorithm-in-c/. The only thing is that I get a NullPointer Exception when I run the code. And I can't wrap my finger around it. I placed a comment in the code where the exception is thrown. The recursive call is returning a null pointer, what is very strange because it can't.. When I place a breakpoint on the null return with the help of a if statement, then I see that there ARE still 2 to 3 empty places.. I probably overlooking something. Hope someone can tell me what I'm doing wrong. Here is the MiniMax code (the tic tac toe code is not important): /* * To change this template, choose Tools | Templates * and open the template in the editor. */ package MiniMax; import Game.Block; import Game.Board; import java.util.ArrayList; public class MiniMax { public static Place getBestMove(Board gameBoard, Block.TYPE player) { Place bestPlace = null; ArrayList<Place> emptyPlaces = gameBoard.getEmptyPlaces(); Board newBoard; //loop trough all the empty places for(Place emptyPlace : emptyPlaces) { newBoard = gameBoard.clone(); newBoard.setBlock(emptyPlace.getRow(), emptyPlace.getCell(), player); //no game won and still room to move if(newBoard.getWinner() == Block.TYPE.NONE && newBoard.getEmptyPlaces().size() > 0) { //is an node (has children) Place tempPlace = getBestMove(newBoard, invertPlayer(player)); //ERROR is thrown here! tempPlace is null. emptyPlace.setScore(tempPlace.getScore()); } else { //is an leaf if(newBoard.getWinner() == Block.TYPE.NONE) { emptyPlace.setScore(0); } else if(newBoard.getWinner() == Block.TYPE.X) { emptyPlace.setScore(-1); } else if(newBoard.getWinner() == Block.TYPE.O) { emptyPlace.setScore(1); } //if this move is better then our prev move, take it! if((bestPlace == null) || (player == Block.TYPE.X && emptyPlace.getScore() < bestPlace.getScore()) || (player == Block.TYPE.O && emptyPlace.getScore() > bestPlace.getScore())) { bestPlace = emptyPlace; } } } //This should never be null, but it does.. return bestPlace; } private static Block.TYPE invertPlayer(Block.TYPE player) { if(player == Block.TYPE.X) { return Block.TYPE.O; } return Block.TYPE.X; } }

  Read the article

• Fast pixelshader 2D raytracing

  - by heishe

  I'd like to do a simple 2D shadow calculation algorithm by rendering my environment into a texture, and then use raytracing to determine what pixels of the texture are not visible to the point light (simply handed to the shader as a vec2 position) . A simple brute force algorithm per pixel would looks like this: line_segment = line segment between current pixel of texture and light source For each pixel in the texture: { if pixel is not just empty space && pixel is on line_segment output = black else output = normal color of the pixel } This is, of course, probably not the fastest way to do it. Question is: What are faster ways to do it or what are some optimizations that can be applied to this technique?

  Read the article

• How to design good & continuous tiles

  - by Mikalichov

  I have trouble designing tiles so that when assembled, they don't look like tiles, but look like an homogeneous thing. For example on the image below: even though the main part of the grass is only one tile, you don't "see" the grid; you know where it is if you look a bit carefully, but it is not obvious. Whereas when I design tiles, you can only see "oh, jeez, 64 times the same tile". A bit like on that image: (taken from a gamedev.stackexchange question, sorry; no critic about the game, but it proves my point, and actually has better tile design that what I manage) I think the main problem is that I design them so they are independent, there is no junction between two tiles if put closed to each other. I think having the tiles more "continuous" would have a smoother effect, but can't manage to do it, it seems overly complex to me. I think it is probably simpler than I think once you know how to do it, but couldn't find a tutorial on that specific point. Is there a known method to design continuous / homogeneous tiles? (my terminology might be totally wrong, don't hesitate to correct me)

  Read the article

< Previous Page | 467 468 469 470 471 472 473 474 475 476 477 478  | Next Page >