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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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  • Best practice for designing a risk-style board game

    - by jyanks
    I'm just trying to figure out how to set up the code for a game like risk... I would like it to be extensible, so that I can have multiple maps (ie- World, North America, Eurasia, Africa) so hardcoding in the map doesn't seem to make a whole lot of sense I'm a bit confused on how/where items should be stored/accessed. Here are the objects I see the game theoretically using: -Countries/Territories -Cities (Can be contained within territories) -Capitols -Connections -Continents -Map -Troops At the moment, I feel like: -A map should have a list of continents and countries. The continents would be more of a 'logical' thing where the continents would just be lists of countries that are checked for bonuses at the start of turns -Countries should have a list of countries that they're connected to for the connections What I can't figure out is: Where do I store the troops? Do I have an object for every single troop or do I just store the number of troops on a country object as an integer? What about capitols and cities? Do those just have a reference to the country they reside in? Is there anything I'm not seeing here that's going to screw me over in the long run with the way that I'm thinking about things now? Any advice would be appreciated.

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  • Elliptical orbit modeling

    - by Nathon
    I'm playing with orbits in a simple 2-d game where a ship flies around in space and is attracted to massive things. The ship's velocity is stored in a vector and acceleration is applied to it every frame as appropriate given Newton's law of universal gravitation. The point masses don't move (there's only 1 right now) so I would expect an elliptical orbit. Instead, I see this: I've tried with nearly circular orbits, and I've tried making the masses vastly different (a factor of a million) but I always get this rotated orbit. Here's some (D) code, for context: void accelerate(Vector delta) { velocity = velocity + delta; // Velocity is a member of the ship class. } // This function is called every frame with the fixed mass. It's a // method of the ship's. void fall(Well well) { // f=(m1 * m2)/(r**2) // a=f/m // Ship mass is 1, so a = f. float mass = 1; Vector delta = well.position - loc; float rSquared = delta.magSquared; float force = well.mass/rSquared; accelerate(delta * force * mass); }

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  • projected textures not appear on the "back" of the mesh as well?

    - by user975135
    I want to create blood wounds on my character's bodies by using projected textures. I've watched some commentaries on games like Left 4 Dead and they say they use projected textures for the blood. But the way projected textures work is that if you project a texture on a rigged character, say his chest, it will also appear on his back. So what's the trick? How to get projected textures appear only on one "side" of the mesh? I use the Panda3D game engine, if that will help.

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  • How can I achieve strong typing with a component messaging system?

    - by Vaughan Hilts
    I'm looking at implementing a messaging system in my entity component system. I've deduced that I can use an event / queue for passing messages, but right now, I just use a generic object and cast out the data I want. I also considered using a dictionary. I see a lot of information on this, but they all involve a lot of casting and guessing. Is there any way to do this elegantly and keep strong typing on my messages?

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  • How to mimic the same fixed-size horizon as in this racing game?

    - by Aybe
    I am trying to replicate the same horizon (buildings and sky) as in the image below: As you can see, the player has advanced in a straight line, yet the horizon has still the same size: This is my attempt using 3D, while it's okay when the player is on the start line: It's not so great when the player advanced as much as in the image no. 2: This is an overview of where the horizon buildings and sky are located: Obviously this won't achieve such effect when one is close to it, so I've tried to scale up the horizon on all axes but the problem is that the buildings are too small depending where you look at them from. How can one mimic such rendering ?

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  • Android: how do I switch between game scenes in a game? Any tutorials?

    - by Flavio
    I am trying to create a simple game using the Android SDK without using AndEngine (or any other game engine). I have plenty of experience designing games from the past, but I'm having lots of trouble trying to use the Android SDK to make my game. By far my biggest hurdle right now is switching between views. That is, for example, going from the menu to the first level, etc. I am using a traditional model I learned (I think it's called a scene stack or something?) in which you push the current scene onto a stack and the game's main loop runs the top item of the stack. This model seems non-trivial to implement in the Android SDK, mostly because Android seems to be picky about which thread instantiates which view. My issue is that I want the first level to show up when you press a button on the main menu, but when I instantiate the first level (the level class extends SurfaceView and implements SurfaceHolder.Callback) I get a runtime error complaining that the thread that runs the main menu can't instantiate this class. Something about calling Looper.prepare(). I figured at this point I was probably doing things wrong. I'm not sure how to specifically phrase my issue into a question, so maybe I should leave it as either 1) Does anybody know a good way (or the 'proper' way) to switch between scenes in an Android game? or 2) Are there any tutorials out there which show how to create a game that doesn't take place entirely in one scene? (I have googled for a while to no avail... maybe someone else knows of one?) Thanks!

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  • Material, Pass, Technique and shaders

    - by Papi75
    I'm trying to make a clean and advanced Material class for the rendering of my game, here is my architecture: class Material { void sendToShader() { program->sendUniform( nameInShader, valueInMaterialOrOther ); } private: Blend blendmode; ///< Alpha, Add, Multiply, … Color ambient; Color diffuse; Color specular; DrawingMode drawingMode; // Line Triangles, … Program* program; std::map<string, TexturePacket> textures; // List of textures with TexturePacket = { Texture*, vec2 offset, vec2 scale} }; How can I handle the link between the Shader and the Material? (sendToShader method) If the user want to send additionals informations to the shader (like time elapsed), how can I allow that? (User can't edit Material class) Thanks!

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  • How can I show a texture in a separate window in an XNA game?

    - by John
    I'm playing around with random map generation and what I want to do is: Input a command to generate a random map. A texture will be created resembling the generation, each pixel resembling each tile. A new window will pop-up, without removing the original one, that will contain the texture. I know how to do this except for the last part. Would someone please tell me how to create a new window and draw a texture to this window?

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  • Drawing different per-pixel data on the screen

    - by Amir Eldor
    I want to draw different per-pixel data on the screen, where each pixel has a specific value according to my needs. An example may be a random noise pattern where each pixel is randomly generated. I'm not sure what is the correct and fastest way to do this. Locking a texture/surface and manipulating the raw pixel data? How is this done in modern graphics programming? I'm currently trying to do this in Pygame but realized I will face the same problem if I go for C/SDL or OpenGL/DirectX.

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  • Rope Colliding with a Rectangle

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

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  • Any significant performance cost to using BlendState.Premultiplied?

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

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  • Object pools for efficient resource management

    - by GameDevEnthusiast
    How can I avoid using default new() to create each object? My previous demo had very unpleasant framerate hiccups during dynamic memory allocations (usually, when arrays are resized), and creating lots of small objects which often contain one pointer to some DirectX resource seems like an awful lot of waste. I'm thinking about: Creating a master look-up table to refer to objects by handles (for safety & ease of serialization), much like EntityList in source engine Creating a templated object pool, which will store items contiguously (more cache-friendly, fast iteration, etc.) and the stored elements will be accessed (by external systems) via the global lookup table. The object pool will use the swap-with-last trick for fast removal (it will invoke the object's ~destructor first) and will update the corresponding indices in the global table accordingly (when growing/shrinking/moving elements). The elements will be copied via plain memcpy(). Is it a good idea? Will it be safe to store objects of non-POD types (e.g. pointers, vtable) in such containers? Related post: Dynamic Memory Allocation and Memory Management

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  • Calculating vertex normals on the GPU

    - by Etan
    I have some height-map sampled on a regular grid stored in an array. Now, I want to use the normals on the sampled vertices for some smoothing algorithm. The way I'm currently doing it is as follows: For each vertex, generate triangles to all it's neighbours. This results in eight neighbours when using the 1-neighbourhood for all vertices except at the borders. +---+---+ ¦ \ ¦ / ¦ +---o---+ ¦ / ¦ \ ¦ +---+---+ For each adjacent triangle, calculate it's normal by taking the cross product between the two distances. As the triangles all have the same size when projected on the xy-plane, I simply average over all eight normals then and store it for this vertex. However, as my data grows larger, this approach takes too much time and I would prefer doing it on the GPU in a shader code. Is there an easy method, maybe if I could store my height-map as a texture?

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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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  • Orthographic Projection with variable FOV

    - by cubrman
    We are building agame with orthographic view. The problem we face is the fact that with different resolution you can see different area of the game world. E.g. if you have higher resolution you can see more around you. To solve this we currently use a common scale factor that every model is scaled by, depending on resolution. But this has drawbacks when drawing shadows - I cannot set a higher view angle for the orthographic shadow camera, while when using the perspective shadow camera I get significantly worse shadow quality. So the question is is there any way to controll FOV when using orthographic projection, or, more specifically, what is the easiest way to scale the world uniformly up or down with orthographic projection matrix? I saw that in 3ds MAX you can control FOV for an orthographic camera I wonder how they implemented it.

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  • Which will be faster? Switching shaders or ignore that some cases don't need full code?

    - by PolGraphic
    I have two types of 2d objects: In first case (for about 70% of objects), I need that code in the shader: float2 texCoord = input.TexCoord + textureCoord.xy But in the second case I have to use: float2 texCoord = fmod(input.TexCoord, texCoordM.xy - textureCoord.xy) + textureCoord.xy I can use second code also for first case, but it will be a little slower (fmod is useless here, input.TexCoord will be always lower than textureCoord.xy - textureCoord.xy for sure). My question is, which way will be faster: Making two independent shaders for both types of rectangles, group rectangles by types and switch shaders during rendering. Make one shader and use some if statement. Make one shader and ignore that sometimes (70% of cases) I don't need to use fmod.

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  • PHP Battle System for RPG game

    - by Jay
    I posted this a while ago on stackoverflow, they thought it would be better place here, I agree. Essentially I know what I want to accomplish, and I have something to the effect of what I want but I am not satisfied with it. Here's the problem. Each user has some states: STR (how hard they hit), DEF (dodging/blocking attacks), SPD (when they can strike), and STAMINA (basically their endurance in game, if this runs out they can no longer fight and lose) What I need is something like this: UserA Stats: STR: 1,000 DEF: 2500 SPD: 2000 (HP: 1000/1000) UserB Stats: STR: 1,500 DEF: 500 SPD: 4000 (HP: 1000/1000) Because the second user has double the speed, he lands twice the amount of hits on the first user, before he gets hit. Because he has less strength than the first users defence, he will do no, to little damage. This is how the battle would theoretically go: UserB strikes UserA for 0 damage UserB strikes UserA for 0 damage UserA strikes UserB for 500 damage UserB strikes UserA for 0 damage UserB strikes UserA for 0 damage UserA strikes UserB for 500 damage, and sends him to the hospital! I was using this code, which is buggy, and not efficient, I just need a better way to do this: http://pastebin.com/15LiQQuJ Oh, and if anyone has some good ideas on how to improve the concept that would be cool too! It's not that elaborate so I'll be thinking of all sorts of things to make it more dynamic. Thanks.

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  • Unity3D - Android pause screen - double click issue

    - by user3666251
    I made a pause script for the game im developing for android. I added the script to the GUITexture I created and placed on the top right side of the screen.The issue stands at the part where if the player clicks the pause button then clicks resume then he wants to pause the game again.When he clicks pause the second time the buttons dont show up unless he clicks again. This is the script : #pragma strict var paused = false; var isButtonVisible : boolean = true; function OnMouseDown(){ this.paused = !this.paused; Time.timeScale = 0; isButtonVisible = true; } function OnGUI(){ if ( isButtonVisible ) { if(this.paused){ if (GUI.Button(Rect(Screen.width/2-100,Screen.height/2+3,200,50),"Restart")){ Application.LoadLevel(Application.loadedLevel); Time.timeScale = 1; isButtonVisible = false; } if (GUI.Button(Rect(Screen.width/2-100,Screen.height/2-50,200,50),"Resume")){ Time.timeScale = 1; isButtonVisible = false; } // Insert the rest of the pause menu logic if (GUI.Button(Rect(Screen.width/2-100,Screen.height/2+56,200,50),"Main Menu")){ Application.LoadLevel ("MainMenu"); isButtonVisible = false; Time.timeScale = 1; } } } } Thank you.

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  • simple collision detection

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

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  • Scaling Sound Effects and Physics with Framerate

    - by Thomas Bradsworth
    (I'm using XNA and C#) Currently, my game (a shooter) runs flawlessly with 60 FPS (which I developed around). However, if the framerate is changed, there are two major problems: Gunshot sound effects are slower Jumping gets messed up Here's how I play gunshot sounds: update(gametime) { if(leftMouseButton.down) { enqueueBulletForSend(); playGunShot(); } } Now, obviously, the frequency of playGunShot depends on the framerate. I can easily fix the issue if the FPS is higher than 60 FPS by capping the shooting rate of the gun, but what if the FPS is less than 60? At first I thought to just loop and play more gunshots per frame, but I found that this can cause audio clipping or make the bullets fire in "clumps." Now for the second issue: Here's how jumping works in my game: if(jumpKey.Down && canJump) { velocity.Y += 0.224f; } // ... (other code) ... if(!onGround) velocity.Y += GRAVITY_ACCELERATION * elapsedSeconds; position += velocity; The issue here is that at < 60 FPS, the "intermediate" velocity is lost and therefore the character jumps lower. At 60 FPS, the game adds more "intermediate" velocities, and therefore the character jumps higher. For example, at 60 FPS, the following occurs: Velocity increased to 0.224 Not on ground, so velocity decreased by X Position increased by (0.224 - X) <-- this is the "intermediate" velocity At 30 FPS, the following occurs: Velocity increased to 0.224 Not on ground, so velocity decreased by 2X Position increased by (0.224 - 2X) <-- the "intermediate" velocity was lost All help is appreciated!

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  • Smooth pixels while rotating sprite

    - by goodm
    I just started with andengine, so this maybe gonna be silly question. How to make my sprites more smooth while I rotate them? Or maybe it because this is screenshot from tablet? Thanks JohnEye it works: Just need to change my BitmapTextureAtlas from: BitmapTextureAtlas carAtlas = new BitmapTextureAtlas(this.getTextureManager(),100, 63); to: BitmapTextureAtlas carAtlas = new BitmapTextureAtlas(this.getTextureManager(),100, 63, TextureOptions.BILINEAR);

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  • Normal map lighting bug in bottom right quadrant

    - by Ryan Capote
    I am currently working on getting normal maps working in my project, and have run into a problem with lighting. As you can see, the normals in the bottom right quadrant of the lighting isn't calculating the correct direction to the light or something. Best seen by the red light If I use flat normals (z normal = 1.0), it seems to be working fine: normals for the tile sheet: Shader: #version 330 uniform sampler2D uDiffuseTexture; uniform sampler2D uNormalsTexture; uniform sampler2D uSpecularTexture; uniform sampler2D uEmissiveTexture; uniform sampler2D uWorldNormals; uniform sampler2D uShadowMap; uniform vec4 uLightColor; uniform float uConstAtten; uniform float uLinearAtten; uniform float uQuadradicAtten; uniform float uColorIntensity; in vec2 TexCoords; in vec2 GeomSize; out vec4 FragColor; float sample(vec2 coord, float r) { return step(r, texture2D(uShadowMap, coord).r); } float occluded() { float PI = 3.14; vec2 normalized = TexCoords.st * 2.0 - 1.0; float theta = atan(normalized.y, normalized.x); float r = length(normalized); float coord = (theta + PI) / (2.0 * PI); vec2 tc = vec2(coord, 0.0); float center = sample(tc, r); float sum = 0.0; float blur = (1.0 / GeomSize.x) * smoothstep(0.0, 1.0, r); sum += sample(vec2(tc.x - 4.0*blur, tc.y), r) * 0.05; sum += sample(vec2(tc.x - 3.0*blur, tc.y), r) * 0.09; sum += sample(vec2(tc.x - 2.0*blur, tc.y), r) * 0.12; sum += sample(vec2(tc.x - 1.0*blur, tc.y), r) * 0.15; sum += center * 0.16; sum += sample(vec2(tc.x + 1.0*blur, tc.y), r) * 0.15; sum += sample(vec2(tc.x + 2.0*blur, tc.y), r) * 0.12; sum += sample(vec2(tc.x + 3.0*blur, tc.y), r) * 0.09; sum += sample(vec2(tc.x + 4.0*blur, tc.y), r) * 0.05; return sum * smoothstep(1.0, 0.0, r); } float calcAttenuation(float distance) { float linearAtten = uLinearAtten * distance; float quadAtten = uQuadradicAtten * distance * distance; float attenuation = 1.0 / (uConstAtten + linearAtten + quadAtten); return attenuation; } vec3 calcFragPosition(void) { return vec3(TexCoords*GeomSize, 0.0); } vec3 calcLightPosition(void) { return vec3(GeomSize/2.0, 0.0); } float calcDistance(vec3 fragPos, vec3 lightPos) { return length(fragPos - lightPos); } vec3 calcLightDirection(vec3 fragPos, vec3 lightPos) { return normalize(lightPos - fragPos); } vec4 calcFinalLight(vec2 worldUV, vec3 lightDir, float attenuation) { float diffuseFactor = dot(normalize(texture2D(uNormalsTexture, worldUV).rgb), lightDir); vec4 diffuse = vec4(0.0); vec4 lightColor = uLightColor * uColorIntensity; if(diffuseFactor > 0.0) { diffuse = vec4(texture2D(uDiffuseTexture, worldUV.xy).rgb, 1.0); diffuse *= diffuseFactor; lightColor *= diffuseFactor; } else { discard; } vec4 final = (diffuse + lightColor); if(texture2D(uWorldNormals, worldUV).g > 0.0) { return final * attenuation; } else { return final * occluded(); } } void main(void) { vec3 fragPosition = calcFragPosition(); vec3 lightPosition = calcLightPosition(); float distance = calcDistance(fragPosition, lightPosition); float attenuation = calcAttenuation(distance); vec2 worldPos = gl_FragCoord.xy / vec2(1024, 768); vec3 lightDir = calcLightDirection(fragPosition, lightPosition); lightDir = (lightDir*0.5)+0.5; float atten = calcAttenuation(distance); vec4 emissive = texture2D(uEmissiveTexture, worldPos); FragColor = calcFinalLight(worldPos, lightDir, atten) + emissive; }

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  • ConsumeStructuredBuffer, what am I doing wrong?

    - by John
    I'm trying to implement the 3rd exercise in chapter 12 of Introduction to 3D Game Programming with DirectX 11, that is: Implement a Compute Shader to calculate the length of 64 vectors. Previous exercises ask you to do the same with typed buffers and regular structured buffers and I had no problems with them. For what I've read, [Consume|Append]StructuredBuffers are bound to the pipeline using UnorderedAccessViews (as long as they use the D3D11_BUFFER_UAV_FLAG_APPEND, and the buffers have both D3D11_BIND_SHADER_RESOURCE and D3D11_BIND_UNORDERED_ACCESS bind flags). Problem is: my AppendStructuredBuffer works, since I can append data to it and retrieve it from the application to write to a results file, but the ConsumeStructuredBuffer always returns zeroed data. Data is in the buffer, since if I change the UAV to a ShaderResourceView and to a StructuredBuffer in the HLSL side it works. I don't know what I am missing: Should I initialize the ConsumeStructuredBuffer on the GPU, or can I do it when I create the buffer (as I amb currently doing). Is it OK to bind the buffer with a UAV as described above? Do I need to bind it as a ShaderResourceView somehow? Maybe I am missing some step? This is the declaration of buffers in the Compute Shader: struct Data { float3 v; }; struct Result { float l; }; ConsumeStructuredBuffer<Data> gInput; AppendStructuredBuffer<Result> gOutput; And here the creation of the buffer and UAV for input data: D3D11_BUFFER_DESC inputDesc; inputDesc.Usage = D3D11_USAGE_DEFAULT; inputDesc.ByteWidth = sizeof(Data) * mNumElements; inputDesc.BindFlags = D3D11_BIND_SHADER_RESOURCE | D3D11_BIND_UNORDERED_ACCESS; inputDesc.CPUAccessFlags = 0; inputDesc.StructureByteStride = sizeof(Data); inputDesc.MiscFlags = D3D11_RESOURCE_MISC_BUFFER_STRUCTURED; D3D11_SUBRESOURCE_DATA vinitData; vinitData.pSysMem = &data[0]; HR(md3dDevice->CreateBuffer(&inputDesc, &vinitData, &mInputBuffer)); D3D11_UNORDERED_ACCESS_VIEW_DESC uavDesc; uavDesc.Format = DXGI_FORMAT_UNKNOWN; uavDesc.ViewDimension = D3D11_UAV_DIMENSION_BUFFER; uavDesc.Buffer.FirstElement = 0; uavDesc.Buffer.Flags = D3D11_BUFFER_UAV_FLAG_APPEND; uavDesc.Buffer.NumElements = mNumElements; md3dDevice->CreateUnorderedAccessView(mInputBuffer, &uavDesc, &mInputUAV); Initial data is an array of Data structs, which contain a XMFLOAT3 with random data. I bind the UAV to the shader using the Effects framework: ID3DX11EffectUnorderedAccessViewVariable* Input = mFX->GetVariableByName("gInput")->AsUnorderedAccessView(); Input->SetUnorderedAccessView(uav); // uav is mInputUAV Any ideas? Thank you.

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  • 2D SAT Collision Detection not working when using certain polygons (With example)

    - by sFuller
    My SAT algorithm falsely reports that collision is occurring when using certain polygons. I believe this happens when using a polygon that does not contain a right angle. Here is a simple diagram of what is going wrong: Here is the problematic code: std::vector<vec2> axesB = polygonB->GetAxes(); //loop over axes B for(int i = 0; i < axesB.size(); i++) { float minA,minB,maxA,maxB; polygonA->Project(axesB[i],&minA,&maxA); polygonB->Project(axesB[i],&minB,&maxB); float intervalDistance = polygonA->GetIntervalDistance(minA, maxA, minB, maxB); if(intervalDistance >= 0) return false; //Collision not occurring } This function retrieves axes from the polygon: std::vector<vec2> Polygon::GetAxes() { std::vector<vec2> axes; for(int i = 0; i < verts.size(); i++) { vec2 a = verts[i]; vec2 b = verts[(i+1)%verts.size()]; vec2 edge = b-a; axes.push_back(vec2(-edge.y,edge.x).GetNormailzed()); } return axes; } This function returns the normalized vector: vec2 vec2::GetNormailzed() { float mag = sqrt( x*x + y*y ); return *this/mag; } This function projects a polygon onto an axis: void Polygon::Project(vec2* axis, float* min, float* max) { float d = axis->DotProduct(&verts[0]); float _min = d; float _max = d; for(int i = 1; i < verts.size(); i++) { d = axis->DotProduct(&verts[i]); _min = std::min(_min,d); _max = std::max(_max,d); } *min = _min; *max = _max; } This function returns the dot product of the vector with another vector. float vec2::DotProduct(vec2* other) { return (x*other->x + y*other->y); } Could anyone give me a pointer in the right direction to what could be causing this bug? Edit: I forgot this function, which gives me the interval distance: float Polygon::GetIntervalDistance(float minA, float maxA, float minB, float maxB) { float intervalDistance; if (minA < minB) { intervalDistance = minB - maxA; } else { intervalDistance = minA - maxB; } return intervalDistance; //A positive value indicates this axis can be separated. } Edit 2: I have recreated the problem in HTML5/Javascript: Demo

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