Search Results

Search found 170 results on 7 pages for 'particle'.

Page 3/7 | < Previous Page | 1 2 3 4 5 6 7  | Next Page >

  • Falling Sand simulation

    - by Erik Forbes
    I'm trying to re-create a 'falling sand' simulation, similar to those various web toys that are out there doing the same thing - and I'm failing pretty hard. I'm not really sure where to begin. I'm trying to use cellular automata to model the behavior of the sand particles, but I'm having trouble figuring out how to make the direction in which I update the 'world' not matter... For example, one of the particle types I'd like to have is Plant. When Plant comes in contact with Water, Plant turns that Water particle into another Plant particle. The problem here though is that if I'm updating the game world from top to bottom and left to right, then a Plant particle placed in the middle of a sea of Water particles will immediately cause all of the Water particles to the right and below that new Plant particle to turn into Plants. This is not the behavior I am expecting. =( I'm having difficulty explaining exactly my difficulty, so I'll try to add more information as best I can as I go along. Suffice it to say that this is very much outside my box, as it were, and I don't even know what to search for.

    Read the article

  • Dealing with state problems in functional programming

    - by Andrew Martin
    I've learned how to program primarily from an OOP standpoint (like most of us, I'm sure), but I've spent a lot of time trying to learn how to solve problems the functional way. I have a good grasp on how to solve calculational problems with FP, but when it comes to more complicated problems I always find myself reverting to needing mutable objects. For example, if I'm writing a particle simulator, I will want particle "objects" with a mutable position to update. How are inherently "stateful" problems typically solved using functional programming techniques?

    Read the article

  • Generating and rendering not point-like particles on GPU

    - by TravisG
    Specifically I'm talking about particles as seen (for example) in the UE4 dev video here. They're not just points and seem to have a nice shape to them that seems to follow their movement. Is it possible to create these kinds of particles (efficiently) completely on the GPU (perhaps through something like motion? Or is the only (or most efficient) way to just create a small particle texture and render small quads for each particle?

    Read the article

  • How can a pygame image be colored?

    - by Juicy
    I'm writing a 2d particle system for a game in Pygame[1]. For the particles, I have an image surface loaded from a file -- basically a white primitive drawn over a transparent background. I'd like the particle engine to emit variously colored particles, but I'm not sure how to tell Pygame to color the surface. I've looked through what passes for documentation, but I'm having trouble finding anything. [1] Yeah, I don't really like Pygame, but my course insists I write this project in Python.

    Read the article

  • Morph a sphere to a cube and a cube to a sphere with GLSL

    - by nkint
    I'm getting started with GLSL with quartz composer. I have a patch with a particle system in which each particle is mapped into a sphere with a blend value. With blend=0 particles are in random positions, blend=1 particles are in the sphere. The code is here: vec3 sphere(vec2 domain) { vec3 range; range.x = radius * cos(domain.y) * sin(domain.x); range.y = radius * sin(domain.y) * sin(domain.x); range.z = radius * cos(domain.x); return range; } // in main: vec2 p0 = gl_Vertex.xy * twopi; vec3 normal = sphere(p0);; vec3 r0 = radius * normal; vec3 vertex = r0; normal = normal * blend + gl_Normal * (1.0 - blend); vertex = vertex * blend + gl_Vertex.xyz * (1.0 - blend); I'd like the particle to be on a cube if blend=0 I've tried to find but I can't figure out some parametric equation for the cube. Maybe it is not the right way?

    Read the article

  • How to set TextureFilter to Point to make example Bloom filter work?

    - by Mr Bell
    I have simple app that renders some particles and now I am trying to apply the bloom shader from the xna samplers ( http://create.msdn.com/en-US/education/catalog/sample/bloom ) to it, but I am running into this exception: "XNA Framework HiDef profile requires TextureFilter to be Point when using texture format Vector4." When the BloomComponent tries to end the sprite batch in the DrawFullscreenQuad method: spriteBatch.Begin(0, BlendState.Opaque, SamplerState.PointWrap, null, null, effect); spriteBatch.Draw(texture, new Rectangle(0, 0, width, height), Color.White); spriteBatch.End(); //<------- Exception thrown here It seems to be related to the pixel shaders that I am using to animate the particle. In a nutshell, I have a texture2d in vector4 format that holds particle positions, and another one for velocities. Here is a snippet from that area: GraphicsDevice.SetRenderTarget(tempRenderTarget); animationEffect.CurrentTechnique = animationEffect.Techniques[technique]; spriteBatch.Begin(SpriteSortMode.Immediate, BlendState.Opaque, SamplerState.PointWrap, DepthStencilState.DepthRead, RasterizerState.CullNone, animationEffect); spriteBatch.Draw(randomValues, new Rectangle(0, 0, width, height), Color.White); spriteBatch.End(); What I comment out the code that calls the particle animation pixel shaders the bloom component runs fine. Is there some state that I need to reset to make the bloom work?

    Read the article

  • CUDA 4.1 Update

    - by N0xus
    I'm currently working on porting a particle system to update on the GPU via the use of CUDA. With CUDA, I've already passed over the required data I need to the GPU and allocated and copied the date via the host. When I build the project, it all runs fine, but when I run it, the project says I need to allocate my h_position pointer. This pointer is my host pointer and is meant to hold the data. I know I need to pass in the current particle position to the required cudaMemcpy call and they are currently stored in a list with a for loop being created and interated for each particle calling the following line of code: m_particleList[i].positionY = m_particleList[i].positionY - (m_particleList[i].velocity * frameTime * 0.001f); My current host side cuda code looks like this: float* h_position; // Your host pointer. This holds the data (I assume it's already filled with the data.) float* d_position; // Your device pointer, we will allocate and fill this float* d_velocity; float* d_time; int threads_per_block = 128; // You should play with this value int blocks = m_maxParticles/threads_per_block + ( (m_maxParticles%threads_per_block)?1:0 ); const int N = 10; size_t size = N * sizeof(float); cudaMalloc( (void**)&d_position, m_maxParticles * sizeof(float) ); cudaMemcpy( d_position, h_position, m_maxParticles * sizeof(float), cudaMemcpyHostToDevice); Both of which were / can be found inside my UpdateParticle() method. I had originally thought it would be a simple case of changing the h_position variable in the cudaMemcpy to m_particleList[i] but then I get the following error: no suitable conversion function from "ParticleSystemClass::ParticleType" to "const void *" exists I've probably messed up somewhere, but could someone please help fix the issues I'm facing. Everything else seems to running fine, it's just when I try to run the program that certain things hit the fan.

    Read the article

  • flexible length struct array inside another struct using C

    - by renz
    Hi I am trying to use C to implement a simple struct: 2 boxes, each contains different number of particles; the exact number of particles are passed in main(). I wrote the following code: typedef struct Particle{ float x; float y; float vx; float vy; }Particle; typedef struct Box{ Particle p[]; }Box; void make_box(Box *box, int number_of_particles); int main(){ Box b1, b2; make_box(&b1, 5); //create a box containing 5 particles make_box(&b2, 10); //create a box containing 10 particles } I've tried to implement make_box with the following code void make_box(struct Box *box, int no_of_particles){ Particle po[no_of_particles]; po[0].x = 1; po[1].x = 2; //so on and so forth... box->p = po; } It's always giving me "invalid use of flexible array member". Greatly appreciated if someone can shed some light on this.

    Read the article

  • Cocos2d shake/accelerometer issue.

    - by Ryan Poolos
    So I a little backstory. I wanted to implement a particle effect and sound effect that both last about 3 sec or so when the user shakes their iDevice. But first issue arrived when the build in UIEvent for shakes refused to work. So I took the advice of a few Cocos veterans to just use some script to get "violent" accelerometer inputs as shakes. Worked great until now. The problem is that if you keep shaking it just stacks the particle and sounds over and over. Now this wouldn't be that big of a deal except it happens even if you are careful to try and not do so. So what I am hoping to do is disable the accelerometer when the particle effect/sound effect start and then reenable it as soon as they finish. Now I don't know if I should do this by schedule, NStimer, or some other function. I am open to ALL suggestions. here is my current "shake" code. - (void)accelerometer:(UIAccelerometer *)accelerometer didAccelerate:(UIAcceleration *)acceleration { const float violence = 1; static BOOL beenhere; BOOL shake = FALSE; if (beenhere) return; beenhere = TRUE; if (acceleration.x > violence * 1.5 || acceleration.x < (-1.5* violence)) shake = TRUE; if (acceleration.y > violence * 2 || acceleration.y < (-2 * violence)) shake = TRUE; if (acceleration.z > violence * 3 || acceleration.z < (-3 * violence)) shake = TRUE; if (shake) { id particleSystem = [CCParticleSystemQuad particleWithFile:@"particle.plist"]; [self addChild: particleSystem]; // Super simple Audio playback for sound effects! [[SimpleAudioEngine sharedEngine] playEffect:@"Sound.mp3"]; shake = FALSE; } beenhere = FALSE; }

    Read the article

  • MPI and C structs

    - by hanno
    I have to admit, I was quite shocked to see how many lines of code are required to transfer one C struct with MPI. Under what circumstances will it work to simply transmit a struct using the predefined dataype MPI_CHAR? Consider the following example: struct particle { double x; double y; long i; }; struct particle p; MPI_Isend(&p, sizeof(particle), MPI_CHAR, tag, MPI_COMM_WORLD, &sendr); In my case, all processes run on the same architecture. Is padding the only issue?

    Read the article

  • How to do the Geometry Wars gravity well effect

    - by Mykel Stone
    I'm not talking about the background grid here, I'm talking about the swirly particles going around the Gravity Wells! I've always liked the effect and decided it'd be a fun experiment to replicate it, I know GW uses Hooke's law all over the place, but I don't think the Particle-to-Well effect is done using springs, it looks like a distance-squared function. Here is a video demonstrating the effect: http://www.youtube.com/watch?v=YgJe0YI18Fg I can implement a spring or gravity effect on some particles just fine, that's easy. But I can't seem to get the effect to look similar to GWs effect. When I watch the effect in game it seems that the particles are emitted in bunches from the Well itself, they spiral outward around the center of the well, and eventually get flung outward, fall back towards the well, and repeat. How does he make the particles spiral outward when spawned? How does he keep the particle bunches together when near the Well but spread away from each other when they're flung outward? How does he keep the particles so strongly attached to the Well?

    Read the article

  • Love2D engine for Lua; What about 3D?

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

    Read the article

  • How do I hook into Tar with BASH?

    - by orb
    Long Story Short I am working with Tar archives that contain PNG images in base64 encoding. I would like to use BASH (or whatever else works) to hook into the extraction function of Tar to decode PNG images from base64 encoding to standard PNG encoding after the files are unpacked. A simple cat $input-file | base64 -d >$output-file will successfully decode the images. Is there a way I can hook into tar -xf so that users do not have to do any (or minimal) extra work to decode the images? In the GNU Tar documentation (http://www.gnu.org/software/tar/manual/html_chapter/Backups.html#SEC97) I found that there are in fact variables reserved to hold the names of functions I desire to be hooked into various moments in Tar program execution. However, the documentation explains that these variables, along with other variables that can be set to configure Tar, are located in a file named backup-specs. Unfortunately, the path to this file is not given. Further, running sudo find / -name backup-specs tells me that this file is not present on my Ubuntu version 13.04 system. Background Information not included in the Long Story Short I have been working on a browser-based (WebGL) particle effect creation application (http://www.particleeffect.org), (https://github.com/cgrabowski/webgl-particle-effect-editor), (https://github.com/cgrabowski/webgl-particle-effect). I have began to write a client-side-only solution for saving and loading effect data as a tar archive. However, since client-side JavaScript has limited capability to process binary data, the images used as textures in the effect are saved with base64 encoding. I have been able to implement saving effect data as a Tar archive (haven't pushed that to Github yet). However, the images present in said Tar archive cannot be manipulated unless they are decoded from base64 encoding.

    Read the article

  • user defined Copy ctor, and copy-ctors further down the chain - compiler bug ? programmers brainbug

    - by J.Colmsee
    Hi. i have a little problem, and I am not sure if it's a compiler bug, or stupidity on my side. I have this struct : struct BulletFXData { int time_next_fx_counter; int next_fx_steps; Particle particles[2];//this is the interesting one ParticleManager::ParticleId particle_id[2]; }; The member "Particle particles[2]" has a self-made kind of smart-ptr in it (resource-counted texture-class). this smart-pointer has a default constructor, that initializes to the ptr to 0 (but that is not important) I also have another struct, containing the BulletFXData struct : struct BulletFX { BulletFXData data; BulletFXRenderFunPtr render_fun_ptr; BulletFXUpdateFunPtr update_fun_ptr; BulletFXExplosionFunPtr explode_fun_ptr; BulletFXLifetimeOverFunPtr lifetime_over_fun_ptr; BulletFX( BulletFXData data, BulletFXRenderFunPtr render_fun_ptr, BulletFXUpdateFunPtr update_fun_ptr, BulletFXExplosionFunPtr explode_fun_ptr, BulletFXLifetimeOverFunPtr lifetime_over_fun_ptr) :data(data), render_fun_ptr(render_fun_ptr), update_fun_ptr(update_fun_ptr), explode_fun_ptr(explode_fun_ptr), lifetime_over_fun_ptr(lifetime_over_fun_ptr) { } /* //USER DEFINED copy-ctor. if it's defined things go crazy BulletFX(const BulletFX& rhs) :data(data),//this line of code seems to do a plain memory-copy without calling the right ctors render_fun_ptr(render_fun_ptr), update_fun_ptr(update_fun_ptr), explode_fun_ptr(explode_fun_ptr), lifetime_over_fun_ptr(lifetime_over_fun_ptr) { } */ }; If i use the user-defined copy-ctor my smart-pointer class goes crazy, and it seems that calling the CopyCtor / assignment operator aren't called as they should. So - does this all make sense ? it seems as if my own copy-ctor of struct BulletFX should do exactly what the compiler-generated would, but it seems to forget to call the right constructors down the chain. compiler bug ? me being stupid ? Sorry about the big code, some small example could have illustrated too. but often you guys ask for the real code, so well - here it is :D EDIT : more info : typedef ParticleId unsigned int; Particle has no user defined copyctor, but has a member of type : Particle { .... Resource<Texture> tex_res; ... } Resource is a smart-pointer class, and has all ctor's defined (also asignment operator) and it seems that Resource is copied bitwise. EDIT : henrik solved it... data(data) is stupid of course ! it should of course be rhs.data !!! sorry for huge amount of code, with a very little bug in it !!! (Guess you shouldn't code at 1 in the morning :D )

    Read the article

  • C++ Filling an 1D array to represent a n-dimensional object based on a straight line segment

    - by Ben
    I'm struggling to find a good way to put this question but here goes. I'm making a system that uses a 1D array implemented as double * parts_ = new double[some_variable];. I want to use this to hold co-ordinates for a particle system that can run in various dimensions. What I want to be able to do is write a generic fill algorithm for filling this in n-dimensions with a common increment in all direction to a variable size. Examples will serve best I think. Consider the case where the number of particles stored by the array is 4 In 1D this produces 4 elements in the array because each particle only has one co-ordinate. 1D: {0, 25, 50, 75}; In 2D this produces 8 elements in the array because each particle has two co-ordinates.. 2D: {0, 0, 0, 25, 25, 0, 25, 25} In 3D this produces 12 elements in the array because each particle now has three co-ordinates {0, 0, 0, 0, 0, 25, 0, 0, 50, ... } These examples are still not quite accurate, but they hopefully will suffice. The way I would do this normally for two dimensions: int i = 0; for(int x = 0; x < parts_size_ / dims_ / dims_ * 25; x += 25) { for(int y = 0; y < parts_size_ / dims_ / dims_ * 25; y += 25) { parts_[i] = x; parts_[i+1] = y; i+=2; // Indentation hates me today .< How can I implement this for n-dimensions where 25 can be any number? The straight line part is because it seems to me logical that a line is a somewhat regular shape in 1D, as is a square in 2D, and a cube in 3D. It seems to me that it would follow that there would be similar shapes in this family that could be implemented for 4D and higher dimensions via a similar fill pattern. This is the shape I wish to set my array to represent.

    Read the article

  • Implementing features in an Entity System

    - by Bane
    After asking two questions on Entity Systems (1, 2), and reading some articles on them, I think that I understand them much better than before. But, I still have some uncertainties, and mainly they are about building a Particle Emitter, an Input system, and a Camera. I obviously still have some problems understanding Entity Systems, and they might apply to a whole other range of objects, but I chose these three because they are very different concepts and should cover a pretty big ground, and help me understand Entity Systems and how to handle problems like these myself, as they come along. I am building an engine in Javascript, and I've implemented most of the core features, which include: input handling, flexible animation system, particle emitter, math classes and functions, scene handling, a camera and a render, and a whole bunch of other things that engines usually support. Then, I read Byte56's answer that got me interested into making the engine into an Entity System one. It would still remain an HTML5 game engine with the basic Scene philosophy, but it should support dynamic creation of entities from components. These are some of the definitions from the previous questions, updated: An Entity is an identifier. It doesn't have any data, it's not an object, it's a simple id that represents an index in the Scene's list of all entities (which I actually plan to implement as a component matrix). A Component is a data holder, but with methods that can operate on that data. The best example is a Vector2D, or a "Position" component. It has data: x and y, but also some methods that make operating on the data a bit easier: add(), normalize(), and so on. A System is something that can operate on a set of entities that meet the certain requirements, usually they (the entities) need to have a specified (by the system itself) set of components to be operated upon. The system is the "logic" part, the "algorithm" part, all the functionality supplied by components is purely for easier data management. The problem that I have now is fitting my old engine concept into this new programming paradigm. Lets start with the simplest one, a Camera. The camera has a position property (Vector2D), a rotation property and some methods for centering it around a point. Each frame, it is fed to a renderer, along with a scene, and all the objects are translated according to it's position. Then the scene is rendered. How could I represent this kind of an object in an Entity System? Would the camera be an entity or simply a component? A combination (see my answer)? Another issues that is bothering me is implementing a Particle Emitter. For what exactly I mean by that, you can check out my video of it: http://youtu.be/BObargIMQsE. The problem I have with this is, again, what should be what. I'm pretty sure that particles themselves shouldn't be entities, as I want to support 10k+ of them, and creating that much entities would be a heavy blow on my performance, I believe. Or maybe not? Depends on the implementation, but anyone with experience: please, do answer. The last bit I wan't to talk about, which is also bugging me the most, is how input should be handled. In my current version of the engine, there is a class called Input. It's a handler that subscribes to browser's events, such as keypresses, and mouse position changes, and also it maintains an internal state. Then, the player class has a react() method, which accepts an input object as an argument. The advantage of this is that the input object could be serialized into JSON and then shared over the network, allowing for smooth multiplayer simulations. But how does this translate into an Entity System?

    Read the article

  • Revolutionary brand powder packing machine price from affecting marketplace boom and put on uniform in addition to a lengthy service life

    - by user74606
    In mining in stone crushing, our machinery company's encounter becomes much more apparent. As a consequence of production capacity in between 600~800t/h of mining stone crusher, stone is mine Mobile Cone Crushing Plant Price 25~40 times, effectively solved the initially mining stone crusher operation because of low yield prices, no upkeep problems. Full chunk of mining stone crusher. Maximum particle size for crushing 1000x1200mm, an effective answer for the original side is mine stone provide, storing significant chunks of stone can not use complications in mines. Completed goods granularity is modest, only 2~15mm, an effective option for the original mine stone size, generally blocking chute production was an issue even the grinding machine. Two types of material mixed great uniformity, desulfurization of mining stone by adding weight considerably. Present quantity added is often reached 60%, effectively minimizing the cost of raw supplies. Electrical energy consumption has fallen. Dropped 1~2KWh/t tons of mining stone electrical energy consumption, annual electricity savings of one hundred,000 yuan. Efficient labor intensity of workers and also the atmosphere. Due to mine stone powder packing machine price a high degree of automation, with out human make contact with supplies, workers working circumstances enhanced significantly. Positive aspects, and along with mine for stone crushing, CS series cone Crusher has the following efficiency traits. CS series cone Crusher Chamber is divided into 3 unique designs, the user is usually chosen in accordance with the scenario on site crushing efficiency is high, uniform item size, grain shape, rolling mortar wall friction and put on uniform in addition to a extended service life of crushing cavity-. CS series cone Crusher utilizes a one of a kind dust-proof seal, sealing dependable, properly extend the service life of the lubricant replacement cycle and parts. CS series Sprial Sand washer price manufacture of important components to choose unique materials. Each and every stroke left rolling mortar wall of broken cone distances, by permitting a lot more products into the crushing cavity, as well as the formation of big discharge volume, speed of supplies by way of the crushing Chamber. This machine makes use of the principle of crushing cavity, also as unique laminated crushing, particle fragmentation, so that the completed product drastically improved the proportions of a cube, needle-shaped stones to lower particle levels extra evenly.

    Read the article

  • Do you need all that data?

    - by BuckWoody
    I read an amazing post over on ars technica (link: http://arstechnica.com/science/news/2010/03/the-software-brains-behind-the-particle-colliders.ars?utm_source=rss&utm_medium=rss&utm_campaign=rss) abvout the LHC, or as they are also known, the "particle colliders". Beyond just the pure scientific geek awesomeness, these instruments have the potential to collect more data than you can (or possibly should) store. Actually, this problem has a lot in common with a BI system. There's so much granular detail available in the source systems that a designer has to decide how, and how much, to roll up the data. Whenver you do that, you lose fidelity, but in many cases that's OK. Take, for example, your car's speedometer. You don't actually need to track each and every point of speed as it happens. You only need to know that you're hovering around the speed limit at a certain point in time. Since this is the way that humans percieve data, is there some lesson we should take in the design of data "flows" - and what implications does this have for new technologies like StreamInsight? Share this post: email it! | bookmark it! | digg it! | reddit! | kick it! | live it!

    Read the article

  • Geometry Shader: distortions

    - by Christophe Lionet
    This is a cross-question from Stack Overflow, I thought it would be more appropriate here. There is a lot of code I could be posting. To avoid overloading the page with code, I will post any part of the code if requested. I am working from the ParticleGS DirectX10 sample, to build a geometry shader based particle system in DirectX 11. Using the sample code, and changing it to my liking, I am able to draw a single quad (which is essentially one particle constantly recreating itself). However, I noticed a problem which was similar to one I once had: the rendered shape is distorted. Here is a video showcasing what is happening. http://youtu.be/6NY_hxjMfwY Now, I used to have this issue when using several effects together, when I realised that I needed to explicitely set the geometry shader to null for the other effects. I solved this problem, as you can see in the video, as the rest of the scene is drawing properly. Note that some sides are being culled somehow, although I turned off culling in my main render state. The texturing is fine too, the texture draws with appropriate proportions relative to the quad. I really don't see what I could be doing wrong here... what would cause the geometry shader to behave in such a way? Again, I will post any piece code you will request.

    Read the article

  • Drawing particles with CPU instead of GPU (XNA)

    - by Helix
    I'm trying out modifications to the following particle system. http://create.msdn.com/en-US/education/catalog/sample/particle_3d I have a function such that when I press Space, all the particles have their positions and velocities set to 0. for (int i = 0; i < particles.GetLength(0); i++) { particles[i].Position = Vector3.Zero; particles[i].Velocity = Vector3.Zero; } However, when I press space, the particles are still moving. If I go to FireParticleSystem.cs I can turn settings.Gravity to 0 and the particles stop moving, but the particles are still not being shifted to (0,0,0). As I understand it, the problem lies in the fact that the GPU is processing all the particle positions, and it's calculating where the particles should be based on their initial position, their initial velocity and multiplying by their age. Therefore, all I've been able to do is change the initial position and velocity of particles, but I'm unable to do it on the fly since the GPU is handling everything. I want the CPU to calculate the positions of the particles individually. This is because I will be later implementing some sort of wind to push the particles around. How do I stop the GPU from taking over? I think it's something to do with VertexBuffers and the draw function, but I don't know how to modify it to make it work.

    Read the article

  • What is a technique for 2D ray-box intersection that is suitable for old console hardware?

    - by DJCouchyCouch
    I'm working on a Sega Genesis homebrew game (it has a 7mhz 68000 CPU). I'm looking for a way to find the intersection between a particle sprite and a background tile. Particles are represented as a point with a movement vector. Background tiles are 8 x 8 pixels, with an (X,Y) position that is always located at a multiple of 8. So, really, I need to find the intersection point for a ray-box collision; I need to find out where along the edge of the tile the ray/particle hits. I have these two hard constraints: I'm working with pixel locations (integers). Floating point is too expensive. It doesn't have to be super exact, just close enough. Multiplications, divisions, dot products, et cetera, are incredibly expensive and are to be avoided. So I'm looking for an efficient algorithm that would fit those constraints. Any ideas? I'm writing it in C, so that would work, but assembly should be good as well.

    Read the article

  • Black Screen: How to set Projection/View Matrix

    - by Lisa
    I have a Windows Phone 8 C#/XAML with DirectX component project. I'm rendering some particles, but each particle is a rectangle versus a square (as I've set the vertices to be positions equally offset from each other). I used an Identity matrix in the view and projection matrix. I decided to add the windows aspect ratio to prevent the rectangles. But now I get a black screen. None of the particles are rendered now. I don't know what's wrong with my matrices. Can anyone see the problem? These are the default matrices in Microsoft's project example. View Matrix: XMVECTOR eye = XMVectorSet(0.0f, 0.7f, 1.5f, 0.0f); XMVECTOR at = XMVectorSet(0.0f, -0.1f, 0.0f, 0.0f); XMVECTOR up = XMVectorSet(0.0f, 1.0f, 0.0f, 0.0f); XMStoreFloat4x4(&m_constantBufferData.view, XMMatrixTranspose(XMMatrixLookAtRH(eye, at, up))); Projection Matrix: void CubeRenderer::CreateWindowSizeDependentResources() { Direct3DBase::CreateWindowSizeDependentResources(); float aspectRatio = m_windowBounds.Width / m_windowBounds.Height; float fovAngleY = 70.0f * XM_PI / 180.0f; if (aspectRatio < 1.0f) { fovAngleY /= aspectRatio; } XMStoreFloat4x4(&m_constantBufferData.projection, XMMatrixTranspose(XMMatrixPerspectiveFovRH(fovAngleY, aspectRatio, 0.01f, 100.0f))); } I've tried modifying them to use cocos2dx's WP8 example. XMMATRIX identityMatrix = XMMatrixIdentity(); float fovy = 60.0f; float aspect = m_windowBounds.Width / m_windowBounds.Height; float zNear = 0.1f; float zFar = 100.0f; float xmin, xmax, ymin, ymax; ymax = zNear * tanf(fovy * XM_PI / 360); ymin = -ymax; xmin = ymin * aspect; xmax = ymax * aspect; XMMATRIX tmpMatrix = XMMatrixPerspectiveOffCenterRH(xmin, xmax, ymin, ymax, zNear, zFar); XMMATRIX projectionMatrix = XMMatrixMultiply(tmpMatrix, identityMatrix); // View Matrix float fEyeX = m_windowBounds.Width * 0.5f; float fEyeY = m_windowBounds.Height * 0.5f; float fEyeZ = m_windowBounds.Height / 1.1566f; float fLookAtX = m_windowBounds.Width * 0.5f; float fLookAtY = m_windowBounds.Height * 0.5f; float fLookAtZ = 0.0f; float fUpX = 0.0f; float fUpY = 1.0f; float fUpZ = 0.0f; XMMATRIX tmpMatrix2 = XMMatrixLookAtRH(XMVectorSet(fEyeX,fEyeY,fEyeZ,0.f), XMVectorSet(fLookAtX,fLookAtY,fLookAtZ,0.f), XMVectorSet(fUpX,fUpY,fUpZ,0.f)); XMMATRIX viewMatrix = XMMatrixMultiply(tmpMatrix2, identityMatrix); XMStoreFloat4x4(&m_constantBufferData.view, viewMatrix); Vertex Shader cbuffer ModelViewProjectionConstantBuffer : register(b0) { //matrix model; matrix view; matrix projection; }; struct VertexInputType { float4 position : POSITION; float2 tex : TEXCOORD0; float4 color : COLOR; }; struct PixelInputType { float4 position : SV_POSITION; float2 tex : TEXCOORD0; float4 color : COLOR; }; PixelInputType main(VertexInputType input) { PixelInputType output; // Change the position vector to be 4 units for proper matrix calculations. input.position.w = 1.0f; //===================================== // TODO: ADDED for testing input.position.z = 0.0f; //===================================== // Calculate the position of the vertex against the world, view, and projection matrices. //output.position = mul(input.position, model); output.position = mul(input.position, view); output.position = mul(output.position, projection); // Store the texture coordinates for the pixel shader. output.tex = input.tex; // Store the particle color for the pixel shader. output.color = input.color; return output; } Before I render the shader, I set the view/projection matrices into the constant buffer void ParticleRenderer::SetShaderParameters() { ViewProjectionConstantBuffer* dataPtr; D3D11_MAPPED_SUBRESOURCE mappedResource; DX::ThrowIfFailed(m_d3dContext->Map(m_constantBuffer.Get(), 0, D3D11_MAP_WRITE_DISCARD, 0, &mappedResource)); dataPtr = (ViewProjectionConstantBuffer*)mappedResource.pData; dataPtr->view = m_constantBufferData.view; dataPtr->projection = m_constantBufferData.projection; m_d3dContext->Unmap(m_constantBuffer.Get(), 0); // Now set the constant buffer in the vertex shader with the updated values. m_d3dContext->VSSetConstantBuffers(0, 1, m_constantBuffer.GetAddressOf() ); // Set shader texture resource in the pixel shader. m_d3dContext->PSSetShaderResources(0, 1, &m_textureView); } Nothing, black screen... I tried so many different look at, eye, and up vectors. I tried transposing the matrices. I've set the particle center position to always be (0, 0, 0), I tried different positions too, just to make sure they're not being rendered offscreen.

    Read the article

< Previous Page | 1 2 3 4 5 6 7  | Next Page >