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• Understanding the Microsoft Permissive License

  - by cable729

  I want to use certain parts of the Game State Management Example in a game I'm making, but I'm not sure how to do this legally. It says in the license that I'm supposed to include a copy of the license with it. So if I make a Visual Studio Solution, I just add the license.txt to the solution? Also, if I use a class and change it, do I have to keep the license info at the top or add that I changed it or what?

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• How to set sprite source coordinates?

  - by ChaosDev

  I am creating own sprite drawer with DX11 on C++. Works fine but I dont know how to apply source rectangle to texture coordinates of rendering surface(for animation sprite sheets) //source = (0,0,32,64); //RECT D3DXVECTOR2 t0 = D3DXVECTOR2( 1.0f, 0.0f); D3DXVECTOR2 t1 = D3DXVECTOR2( 1.0f, 1.0f); D3DXVECTOR2 t2 = D3DXVECTOR2( 0.0f, 1.0f); D3DXVECTOR2 t3 = D3DXVECTOR2( 0.0f, 1.0f); D3DXVECTOR2 t4 = D3DXVECTOR2( 0.0f, 0.0f); D3DXVECTOR2 t5 = D3DXVECTOR2( 1.0f, 0.0f); VertexPositionColorTexture vertices[] = { { D3DXVECTOR3( dest.left+dest.right, dest.top, z),D3DXVECTOR4(1,1,1,1), t0}, { D3DXVECTOR3( dest.left+dest.right, dest.top+dest.bottom, z),D3DXVECTOR4(1,1,1,1), t1}, { D3DXVECTOR3( dest.left, dest.top+dest.bottom, z),D3DXVECTOR4(1,1,1,1), t2}, { D3DXVECTOR3( dest.left, dest.top+dest.bottom, z),D3DXVECTOR4(1,1,1,1), t3}, { D3DXVECTOR3( dest.left , dest.top, z),D3DXVECTOR4(1,1,1,1), t4}, { D3DXVECTOR3( dest.left+dest.right, dest.top, z),D3DXVECTOR4(1,1,1,1), t5}, };

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• Animations not accepted in animator

  - by Lautaro

  In the official Unity Animator State Machine tutorial video animation clips are dragged out from the assets folder into the animator and dropped. I have a 3D model that i bought online to experiment with that comes with animations. I added a custom made animation as well. These all work well in my demo project. But when i add a animator to the assets and try to drag and drop animations onto it it doesnt work. I get a forbidden-sign as a mouse pointer. I try to add animations through the inspector but that does not work either. The tutorials makes it seem so easy and does not talk anything about what animations can be used. What am i doing wrong?

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• Text on a model

  - by alecnash

  I am trying to put some text on a Model and I want it to be dynamic. Did some research and came up with drawing the text on the texture and then set it on the model. I use something like this: public static Texture2D SpriteFontTextToTexture(SpriteFont font, string text, Color backgroundColor, Color textColor) { Size = font.MeasureString(text); RenderTarget2D renderTarget = new RenderTarget2D(GraphicsDevice, (int)Size.X, (int)Size.Y); GraphicsDevice.SetRenderTarget(renderTarget); GraphicsDevice.Clear(Color.Transparent); Spritbatch.Begin(); //have to redo the ColorTexture Spritbatch.Draw(ColorTexture.Create(GraphicsDevice, 1024, 1024, backgroundColor), Vector2.Zero, Color.White); Spritbatch.DrawString(font, text, Vector2.Zero, textColor); Spritbatch.End(); GraphicsDevice.SetRenderTarget(null); return renderTarget; } When I was working with primitives and not models everything worked fine because I set the texture exactly where I wanted but with the model (RoundedRect 3D button). It now looks like that: Is there a way to have the text centered only on one side?

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• What is the simplest way to render video into memory (for drawing to a texture) in .NET?

  - by sebf

  In my project I would like to be able to play back video on surfaces in the world. I intend to do this by having the video frames rendered to a block of memory, then use this to update a texture each frame. Everything is in place - except for the part that actually gets the video. I have looked on Google and found that the video library world is very expansive (and geared towards video processing), and am having trouble finding a suitable one. FFMpeg is very comprehensive, but is an entire suite and would take a good amount of work to integrate. So far the most promising library I've found is the one based on the VLC player libraries - by virtue of it using the same resources as VLC Player it is known to be very capable; it also renders to blocks of memory, but the API (at least of the one on Codeplex) is more of a port of the C++ API rather than a managed wrapper. The 'solution' can be any wrapper/API/library, but with characteristics that make it suitable for use in a rendering engine, namely: Renders the video frame data to memory, so it can be picked up and passed to a texture on the GPU easily. Super simple - all that is needed is a way to load, jump and render a frame programatically - ideally it would use the systems codecs and not require an assortment of plugins. Permissive license (LGPL or more free-er) .NET bindings at least; all the better if it is natively managed Can anyone suggest a lightweight, (.NET) library, that can take a video file, and spit out some frames into a byte[]?

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• Accounting for waves when doing planar reflections

  - by CloseReflector

  I've been studying Nvidia's examples from the SDK, in particular the Island11 project and I've found something curious about a piece of HLSL code which corrects the reflections up and down depending on the state of the wave's height. Naturally, after examining the brief paragraph of code: // calculating correction that shifts reflection up/down according to water wave Y position float4 projected_waveheight = mul(float4(input.positionWS.x,input.positionWS.y,input.positionWS.z,1),g_ModelViewProjectionMatrix); float waveheight_correction=-0.5*projected_waveheight.y/projected_waveheight.w; projected_waveheight = mul(float4(input.positionWS.x,-0.8,input.positionWS.z,1),g_ModelViewProjectionMatrix); waveheight_correction+=0.5*projected_waveheight.y/projected_waveheight.w; reflection_disturbance.y=max(-0.15,waveheight_correction+reflection_disturbance.y); My first guess was that it compensates for the planar reflection when it is subjected to vertical perturbation (the waves), shifting the reflected geometry to a point where is nothing and the water is just rendered as if there is nothing there or just the sky: Now, that's the sky reflecting where we should see the terrain's green/grey/yellowish reflection lerped with the water's baseline. My problem is now that I cannot really pinpoint what is the logic behind it. Projecting the actual world space position of a point of the wave/water geometry and then multiplying by -.5f, only to take another projection of the same point, this time with its y coordinate changed to -0.8 (why -0.8?). Clues in the code seem to indicate it was derived with trial and error because there is redundancy. For example, the author takes the negative half of the projected y coordinate (after the w divide): float waveheight_correction=-0.5*projected_waveheight.y/projected_waveheight.w; And then does the same for the second point (only positive, to get a difference of some sort, I presume) and combines them: waveheight_correction+=0.5*projected_waveheight.y/projected_waveheight.w; By removing the divide by 2, I see no difference in quality improvement (if someone cares to correct me, please do). The crux of it seems to be the difference in the projected y, why is that? This redundancy and the seemingly arbitrary selection of -.8f and -0.15f lead me to conclude that this might be a combination of heuristics/guess work. Is there a logical underpinning to this or is it just a desperate hack? Here is an exaggeration of the initial problem which the code fragment fixes, observe on the lowest tessellation level. Hopefully, it might spark an idea I'm missing. The -.8f might be a reference height from which to deduce how much to disturb the texture coordinate sampling the planarly reflected geometry render and -.15f might be the lower bound, a security measure.

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• Sorting for 2D Drawing

  - by Nexian

  okie, looked through quite a few similar questions but still feel the need to ask mine specifically (I know, crazy). Anyhoo: I am drawing a game in 2D (isometric) My objects have their own arrays. (i.e. Tiles[], Objects[], Particles[], etc) I want to have a draw[] array to hold anything that will be drawn. Because it is 2D, I assume I must prioritise depth over any other sorting or things will look weird. My game is turn based so Tiles and Objects won't be changing position every frame. However, Particles probably will. So I am thinking I can populate the draw[] array (probably a vector?) with what is on-screen and have it add/remove object, tile & particle references when I pan the screen or when a tile or object is specifically moved. No idea how often I'm going to have to update for particles right now. I want to do this because my game may have many thousands of objects and I want to iterate through as few as possible when drawing. I plan to give each element a depth value to sort by. So, my questions: Does the above method sound like a good way to deal with the actual drawing? What is the most efficient way to sort a vector? Most of the time it wont require efficiency. But for panning the screen it will. And I imagine if I have many particles on screen moving across multiple tiles, it may happen quite often. For reference, my screen will be drawing about 2,800 objects at any one time. When panning, it will be adding/removing about ~200 elements every second, and each new element will need adding in the correct location based on depth.

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• iOS + cocos2d: how to account for sprite's position for the different device dimensions in an universal app?

  - by fuzzlog

  All the questions I've seen regarding iOS universal apps (with or without cocos2d) deal with the "how to add graphics to a universal app". My question is, how does the code need to be written to ensure that the sprites appear appropriately on the screen (given that an iPhone 5's resolution is not proportional to an iPad's resolution)? Is it just a bunch of "if" statements and duplicate code or do iOS/cocos2d provide common function calls that will place the sprites at an appropriate position?

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• BoundingSpheres move when they should not

  - by NDraskovic

  I have a XNA 4.0 project in which I load a file that contains type and coordinates of items I need to draw to the screen. Also I need to check if one particular type (the only movable one) is passing in front or trough other items. This is the code I use to load the configuration: if (ks.IsKeyDown(Microsoft.Xna.Framework.Input.Keys.L)) { this.GraphicsDevice.Clear(Color.CornflowerBlue); Otvaranje.ShowDialog(); try { using (StreamReader sr = new StreamReader(Otvaranje.FileName)) { String linija; while ((linija = sr.ReadLine()) != null) { red = linija.Split(','); model = red[0]; x = red[1]; y = red[2]; z = red[3]; elementi.Add(Convert.ToInt32(model)); podatci.Add(new Vector3(Convert.ToSingle(x), Convert.ToSingle(y), Convert.ToSingle(z))); sfere.Add(new BoundingSphere(new Vector3(Convert.ToSingle(x), Convert.ToSingle(y), Convert.ToSingle(z)), 1f)); } } } catch (Exception ex) { Window.Title = ex.ToString(); } } The "Otvaranje" is an OpenFileDialog object, "elementi" is a List (determines the type of item that would be drawn), podatci is a List (determines the location where the items will be drawn) and sfere is a List. Now I solved the picking algorithm (checking for ray and bounding sphere intersection) and it works fine, but the collision detection does not. I noticed, while using picking, that BoundingSphere's move even though the objects that they correspond to do not. The movable object is drawn to the world1 Matrix, and the static objects are drawn into the world2 Matrix (world1 and world2 have the same values, I just separated them so that the static elements would not move when the movable one does). The problem is that when I move the item I want, all boundingSpheres move accordingly. How can I move only the boundingSphere that corresponds to that particular item, and leave the rest where they are?

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• Efficient skeletal animation

  - by Will

  I am looking at adopting a skeletal animation format (as prompted here) for an RTS game. The individual representation of each model on-screen will be small but there will be lots of them! In skeletal animation e.g. MD5 files, each individual vertex can be attached to an arbitrary number of joints. How can you efficiently support this whilst doing the interpolation in GLSL? Or do engines do their animation on the CPU? Or do engines set arbitrary limits on maximum joints per vertex and invoke nop multiplies for those joints that don't use the maximum number? Are there games that use skeletal animation in an RTS-like setting thus proving that on integrated graphics cards I have nothing to worry about in going the bones route?

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• Do I need the 'w' component in my Vector class?

  - by bobobobo

  Assume you're writing matrix code that handles rotation, translation etc for 3d space. Now the transformation matrices have to be 4x4 to fit the translation component in. However, you don't actually need to store a w component in the vector do you? Even in perspective division, you can simply compute and store w outside of the vector, and perspective divide before returning from the method. For example: // post multiply vec2=matrix*vector Vector operator*( const Matrix & a, const Vector& v ) { Vector r ; // do matrix mult r.x = a._11*v.x + a._12*v.y ... real w = a._41*v.x + a._42*v.y ... // perspective divide r /= w ; return r ; } Is there a point in storing w in the Vector class?

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• Light on every model and not in the whole scene

  - by alecnash

  I am using a custom shader and try to pass the effect on my Models like that: foreach (ModelMesh mesh in Model.Meshes) { foreach (ModelMeshPart part in mesh.MeshParts) { part.Effect = effect; } mesh.Draw(); } My only issue is that every Model now has its own light source in it. Why is this happening and is this a problem of my shader? Edit: These are the parameters passed to the shader: private void Get_lambertEffect() { if (_lambertEffect == null) _lambertEffect = Engine.LambertEffect; //Lambert technique (LambertWithShadows, LambertWithShadows2x2PCF, LambertWithShadows3x3PCF) _lambertEffect.CurrentTechnique = _lambertEffect.Techniques["LambertWithShadows3x3PCF"]; _lambertEffect.Parameters["texelSize"].SetValue(Engine.ShadowMap.TexelSize); //ShadowMap parameters _lambertEffect.Parameters["lightViewProjection"].SetValue(Engine.ShadowMap.LightViewProjectionMatrix); _lambertEffect.Parameters["textureScaleBias"].SetValue(Engine.ShadowMap.TextureScaleBiasMatrix); _lambertEffect.Parameters["depthBias"].SetValue(Engine.ShadowMap.DepthBias); _lambertEffect.Parameters["shadowMap"].SetValue(Engine.ShadowMap.ShadowMapTexture); //Camera view and projection parameters _lambertEffect.Parameters["view"].SetValue(Engine._camera.ViewMatrix); _lambertEffect.Parameters["projection"].SetValue(Engine._camera.ProjectionMatrix); _lambertEffect.Parameters["world"].SetValue( Matrix.CreateScale(Size) * world ); //Light and color _lambertEffect.Parameters["lightDir"].SetValue(Engine._sourceLight.Direction); _lambertEffect.Parameters["lightColor"].SetValue(Engine._sourceLight.Color); _lambertEffect.Parameters["materialAmbient"].SetValue(Engine.Material.Ambient); _lambertEffect.Parameters["materialDiffuse"].SetValue(Engine.Material.Diffuse); _lambertEffect.Parameters["colorMap"].SetValue(ColorTexture.Create(Engine.GraphicsDevice, Color.Red)); }

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• Are there any OpenGL ES 2.0 examples for JOGL?

  - by fjdutoit

  I've scoured the internet for the last few hours looking for an example of how to run even the most basic OpenGL ES 2 example using JOGL but "by Jupiter!" it has been a total fail. I tried converting the android example from the OpenGL ES 2.0 Programming Guide examples (and at the same time looking at the WebGL example -- which worked fine) yet without any success. Are there any examples out there? If anyone else wants some extra help regarding this question see this thread on the official Jogamp forum.

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• Models from 3ds max lose their transformations when input into XNA

  - by jacobian

  I am making models in 3ds max. However when I export them to .fbx format and then input them into XNA, they lose their scaling. -It is most likely something to do with not using the transforms from the model correctly, is the following code correct -using xna 3.0 Matrix[] transforms=new Matrix[playerModel.Meshes.Count]; playerModel.CopyAbsoluteBoneTransformsTo(transforms); // Draw the model. int count = 0; foreach (ModelMesh mesh in playerModel.Meshes) { foreach (BasicEffect effect in mesh.Effects) { effect.World = transforms[count]* Matrix.CreateScale(scale) * Matrix.CreateRotationX((float)MathHelper.ToRadians(rx)) * Matrix.CreateRotationY((float)MathHelper.ToRadians(ry)) * Matrix.CreateRotationZ((float)MathHelper.ToRadians(rz))* Matrix.CreateTranslation(position); effect.View = view; effect.Projection = projection; effect.EnableDefaultLighting(); } count++; mesh.Draw(); }

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• How can I improve the "smoothness" of a 2D side-scrolling iPhone game?

  - by MrDatabase

  I'm working on a relatively simple 2D side-scrolling iPhone game. The controls are tilt-based. I use OpenGL ES 1.1 for the graphics. The game state is updated at a rate of 30 Hz... And the drawing is updated at a rate of 30 fps (via NSTimer). The smoothness of the drawing is ok... But not quite as smooth as a game like iFighter. What can I do to improve the smoothness of the game? Here are the potential issues I've briefly considered: I'm varying the opacity of up to 15 "small" (20x20 pixels) textures at a time... Apparently varying the opacity in this manner can degrade drawing performance I'm rendering at only 30 fps (via NSTimer)... Perhaps 2D games like iFighter are rendered at a higher frame rate? Perhaps the game state could be updated at a faster rate? Note the acceleration vales are updated at 100 Hz... So I could potentially update part of the game state at 100 hz All of my textures are PNG24... Perhaps PNG8 would help (due to smaller size etc)

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• Circular class dependency

  - by shad0w

  Is it bad design to have 2 classes which need each other? I'm writing a small game in which I have a GameEngine class which has got a few GameState objects. To access several rendering methods, these GameState objects also need to know the GameEngine class - so it's a circular dependency. Would you call this bad design? I am just asking, because I am not quite sure and at this time I am still able to refactor these things.

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• Procedural Planets, Heightmaps and Textures

  - by henryprescott

  I am currently working on an OpenGL procedural planet generator. I hope to use it for a space RPG, that will not allow players to go down to the surface of a planet so I have ignored anything ROAM related. At the momement I am drawing a cube with VBOs and mapping onto a sphere. I am familiar with most fractal heightmap generating techniques and have already implemented my own version of midpoint displacement(not that useful in this case I know). My question is, what is the best way to procedurally generate the heightmap. I have looked at libnoise which allows me to make tilable heightmaps/textures, but as far as I can see I would need to generate a net like this. Leaving the tiling obvious. Could anyone advise me on the best route to take? Any input would be much appreciated. Thanks, Henry.

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• Will we see a trend of "3d" games coming up in the near future?

  - by Vish

  I've noticed that the trend of movies is diving into the world of movies with 3-dimensional camera.For me it provoked a thought as if it was the same feeling people got when they saw a colour movie for the first time, like in the transition from black and white to colour it is a whole new experience. For the first time we are experiencing the Z(depth) factor and I really mean when I said "experiencing". So my question is or maybe if not a question, but Is there a possibility of a genre of 3d camera games upcoming?

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• Character equipment combinations

  - by JimFing

  I'm developing a 2d isometric game (typical Tolkien RPG) and wondering how to handle character/equipment combinations. So for example, the player wears leather boots with chain-mail and a wooden shield and a sword - but then picks up plate-armour instead of chain-mail. I'm using Blender3D to create objects, environments and characters in 3D, then a script runs to render all 3D meshes into 2D orthographic tile maps. So I can use this script to create all the combinations of character equipment for me, but there would be an explosion in terms of the combinations required.

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• How can I cleanly and elegantly handle data and dependancies between classes

  - by Neophyte

  I'm working on 2d topdown game in SFML 2, and need to find an elegant way in which everything will work and fit together. Allow me to explain. I have a number of classes that inherit from an abstract base that provides a draw method and an update method to all the classes. In the game loop, I call update and then draw on each class, I imagine this is a pretty common approach. I have classes for tiles, collisions, the player and a resource manager that contains all the tiles/images/textures. Due to the way input works in SFML I decided to have each class handle input (if required) in its update call. Up until now I have been passing in dependencies as needed, for example, in the player class when a movement key is pressed, I call a method on the collision class to check if the position the player wants to move to will be a collision, and only move the player if there is no collision. This works fine for the most part, but I believe it can be done better, I'm just not sure how. I now have more complex things I need to implement, eg: a player is able to walk up to an object on the ground, press a key to pick it up/loot it and it will then show up in inventory. This means that a few things need to happen: Check if the player is in range of a lootable item on keypress, else do not proceed. Find the item. Update the sprite texture on the item from its default texture to a "looted" texture. Update the collision for the item: it might have changed shape or been removed completely. Inventory needs to be updated with the added item. How do I make everything communicate? With my current system I will end up with my classes going out of scope, and method calls to each other all over the place. I could tie up all the classes in one big manager and give each one a reference to the parent manager class, but this seems only slightly better. Any help/advice would be greatly appreciated! If anything is unclear, I'm happy to expand on things.

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• How can state changes be batched while adhering to opaque-front-to-back/alpha-blended-back-to-front?

  - by Sion Sheevok

  This is a question I've never been able to find the answer to. Batching objects with similar states is a major performance gain when rendering many objects. However, I've been learned various rules when drawing objects in the game world. Draw all opaque objects, front-to-back. Draw all alpha-blended objects, back-to-front. Some of the major parameters to batch by, as I understand it, are textures, vertex buffers, and index buffers. It seems that, as long as you are adhering to the above two rules, there's little to be done in regards to batching. I see one possibility to batch, while still adhering to the above two rules. Opaque objects can still be drawn out of depth-order, because drawing them front-to-back is merely a fillrate optimization, meanwhile state changes may very well be far more expensive than the overdraw of drawing out of depth-order. However, non-opaque objects, those that require alpha-blending at least, must be drawn back-to-front in order to avoid rendering artifacts. Is the loss of the fillrate optimization for opaques worth the state batching optimization?

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• Soccer Game only with National Team names (country names) what about player names? [duplicate]

  - by nightkarnation

  This question already has an answer here: Legal issues around using real players names and team emblems in an open source game 2 answers Ok...this question hasn't been asked before, its very similar to some, but here's the difference: I am making a soccer/football simulator game, that only has national teams (with no official logos) just the country names and flags. Now, my doubt is the following...can I use real player names (that play or played on that national team?) From what I understand if I use a player name linked to a club like Barcelona FC (not a national team) I need the right from the club and the association that club is linked to, right? But If I am only linking the name just to a country...I might just need the permission of the actual player (that I am using his name) and not any other associations, correct? Thanks a lot in advance! Cheers, Diego.

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• Information about rendering, batches, the graphical card, performance etc. + XNA?

  - by Aidiakapi

  I know the title is a bit vague but it's hard to describe what I'm really looking for, but here goes. When it comes to CPU rendering, performance is mostly easy to estimate and straightforward, but when it comes to the GPU due to my lack of technical background information, I'm clueless. I'm using XNA so it'd be nice if theory could be related to that. So what I actually wanna know is, what happens when and where (CPU/GPU) when you do specific draw actions? What is a batch? What influence do effects, projections etc have? Is data persisted on the graphics card or is it transferred over every step? When there's talk about bandwidth, are you talking about a graphics card internal bandwidth, or the pipeline from CPU to GPU? Note: I'm not actually looking for information on how the drawing process happens, that's the GPU's business, I'm interested on all the overhead that precedes that. I'd like to understand what's going on when I do action X, to adapt my architectures and practices to that. Any articles (possibly with code examples), information, links, tutorials that give more insight in how to write better games are very much appreciated. Thanks :)

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• snapping an angle to the closest cardinal direction

  - by Josh E

  I'm developing a 2D sprite-based game, and I'm finding that I'm having trouble with making the sprites rotate correctly. In a nutshell, I've got spritesheets for each of 5 directions (the other 3 come from just flipping the sprite horizontally), and I need to clamp the velocity/rotation of the sprite to one of those directions. My sprite class has a pre-computed list of radians corresponding to the cardinal directions like this: protected readonly List<float> CardinalDirections = new List<float> { MathHelper.PiOver4, MathHelper.PiOver2, MathHelper.PiOver2 + MathHelper.PiOver4, MathHelper.Pi, -MathHelper.PiOver4, -MathHelper.PiOver2, -MathHelper.PiOver2 + -MathHelper.PiOver4, -MathHelper.Pi, }; Here's the positional update code: if (velocity == Vector2.Zero) return; var rot = ((float)Math.Atan2(velocity.Y, velocity.X)); TurretRotation = SnapPositionToGrid(rot); var snappedX = (float)Math.Cos(TurretRotation); var snappedY = (float)Math.Sin(TurretRotation); var rotVector = new Vector2(snappedX, snappedY); velocity *= rotVector; //...snip private float SnapPositionToGrid(float rotationToSnap) { if (rotationToSnap == 0) return 0.0f; var targetRotation = CardinalDirections.First(x => (x - rotationToSnap >= -0.01 && x - rotationToSnap <= 0.01)); return (float)Math.Round(targetRotation, 3); } What am I doing wrong here? I know that the SnapPositionToGrid method is far from what it needs to be - the .First(..) call is on purpose so that it throws on no match, but I have no idea how I would go about accomplishing this, and unfortunately, Google hasn't helped too much either. Am I thinking about this the wrong way, or is the answer staring at me in the face?

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• In 3D camera math, calculate what Z depth is pixel unity for a given FOV

  - by badweasel

  I am working in iOS and OpenGL ES 2.0. Through trial and error I've figured out a frustum to where at a specific z depth pixels drawn are 1 to 1 with my source textures. So 1 pixel in my texture is 1 pixel on the screen. For 2d games this is good. Of course it means that I also factor in things like the size of the quad and the size of the texture. For example if my sprite is a quad 32x32 pixels. The quad size is 3.2 units wide and tall. And the texcoords are 32 / the size of the texture wide and tall. Then the frustum is: matrixFrustum(-(float)backingWidth/frustumScale,(float)backingWidth/frustumScale, -(float)backingHeight/frustumScale, (float)backingHeight/frustumScale, 40, 1000, mProjection); Where frustumScale is 800 for a retina screen. Then at a distance of 800 from camera the sprite is pixel for pixel the same as photoshop. For 3d games sometimes I still want to be able to do this. But depending on the scene I sometimes need the FOV to be different things. I'm looking for a way to figure out what Z depth will achieve this same pixel unity for a given FOV. For this my mProjection is set using: matrixPerspective(cameraFOV, near, far, (float)backingWidth / (float)backingHeight, mProjection); With testing I found that at an FOV of 45.0 a Z of 38.5 is very close to pixel unity. And at an FOV of 30.0 a Z of 59.5 is about right. But how can I calculate a value that is spot on? Here's my matrixPerspecitve code: void matrixPerspective(float angle, float near, float far, float aspect, mat4 m) { //float size = near * tanf(angle / 360.0 * M_PI); float size = near * tanf(degreesToRadians(angle) / 2.0); float left = -size, right = size, bottom = -size / aspect, top = size / aspect; // Unused values in perspective formula. m[1] = m[2] = m[3] = m[4] = 0; m[6] = m[7] = m[12] = m[13] = m[15] = 0; // Perspective formula. m[0] = 2 * near / (right - left); m[5] = 2 * near / (top - bottom); m[8] = (right + left) / (right - left); m[9] = (top + bottom) / (top - bottom); m[10] = -(far + near) / (far - near); m[11] = -1; m[14] = -(2 * far * near) / (far - near); } And my mView is set using: lookAtMatrix(cameraPos, camLookAt, camUpVector, mView); * UPDATE * I'm going to leave this here in case anyone has a different solution, can explain how they do it, or why this works. This is what I figured out. In my system I use a 10th scale unit to pixels on non-retina displays and a 20th scale on retina displays. The iPhone is 640 pixels wide on retina and 320 pixels wide on non-retina (obsolete). So if I want something to be the full screen width I divide by 20 to get the OpenGL unit width. Then divide that by 2 to get the left and right unit position. Something 32 units wide centered on the screen goes from -16 to +16. Believe it or not I have an excel spreadsheet do all this math for me and output all the vertex data for my sprite sheet. It's an arbitrary thing I made up to do .1 units = 1 non-retina pixel or 2 retina pixels. I could have made it .01 units = 2 pixels and someday I might switch to that. But for now it's the other. So the width of the screen in units is 32.0, and that means the left most pixel is at -16.0 and the right most is at 16.0. After messing a bit I figured out that if I take the [0] value of an identity modelViewProjection matrix and multiply it by 16 I get the depth required to get 1:1 pixels. I don't know why. I don't know if the 16 is related to the screen size or just a lucky guess. But I did a test where I placed a sprite at that calculated depth and varied the FOV through all the valid values and the object stays steady on screen with 1:1 pixels. So now I'm just calculating the unityDepth that way. If someone gives me a better answer I'll checkmark it.

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