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  • Skyrim Nexus Mods on Xbox 360 by use of dawnguard?

    - by user17895
    i think it's possible i opened up the dawnguard marketplace content and it consists 3 files: dawnguard.bsa < mod dawnguard.esp <- mod installing file. and spa.bin <-dont know where this is for. and it has been confirmed you can use the top 2 files on pc for a not fully functional dawnguard (barely functional to be exact) and if we could just replace or add a few other bsa and esp files to this marketplace content we could get mods up and running on xbox altough i need confirmation on this. I also have no clue where the spa.bin file for is, i need to examine it some further. Further this is adding a few non-distributed Files to marketplace content and wont get you booted from XBL. Also if anyone wants to examine these files for further information i will gladly share them with you. if you have any information or answers please email me at [email protected] thx

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  • HTML5 game engine for a 2D or 2.5D RPG style "map walk"

    - by stargazer
    please help me to choose a HTML5 game engine or Javascript libraries I want to do the following in the game: when the game starts a part the huge map (full size of the map: about 7 screens) is shown. The map itself is completely designed in the editor mapeditor.org (or in some comparable editor - if you know a good alternative to mapeditor.org - let me know) and loaded at runtime or at design time. The game engine should support loading of isometric maps (well, in worst case only orthogonal maps will be sufficient) both "tile layer" and "object layer" from mapeditor.org should be supported. Scrolling/performance of this map should be fast enough. The map and the game should be either in 2D (orthogonal map) or in 2.5D (isometric map) The game engine should support movement of sprites with animation. Let say I have a sprite for "human" with animation sequences showing "walking" in 8 directions - it should be imported into game engine and should "walk" on the map without writing a lot of Javascript code. Automatic scrolling of the map the "human" nears the screen border. Collision detection, "solid" objects. The mapeditor.org supports properies on tiles. Let say I assign a "solid" property to some tiles in editor. It should be easy to check this "solid" property in the game engine and implement kind of "solid" behavior, so the animanted sprites do not walk through the walls. Collision detection - it should be easy to implement some custom functionality like "when sprite A is close to sprite B - call this function" Showing "dialogs" or popup windows on top of the map - should be easy to implement. Cross-browser audio support - (it is implemented quite well in construct 2 from scirra, so I'm looking for the comparable audio quality) The game itself is a king of RPG but without fighting scenes and without huge "inventory". The main character just walking on the map, discovers some things, there are dialogs and sounds. The functionality of this example from sprite.js http://batiste.dosimple.ch/sprite.js/tests/mapeditor/map_reader.html is very close to what I'm developing. But I'm not a Javascript guru (and a very lazy guy) and would like to write even less Javascript code as in the example...

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  • Can I use GLFW and GLEW together in the same code

    - by Brendan Webster
    I use the g++ compiler, which could be causing the main problem, but I'm using GLFW for window and input management, and I am using GLEW so that I can use OpenGL 3.x functionality. I loaded in models and then tried to make Vertex and Index buffers for the data, but it turned out that I kept getting segmentation faults in the program. I finally figured out that GLEW just wasn't working with GLFW included. Do they not work together? Also I've done the context creation through GLFW so that may be another factor in the problem.

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  • Atmospheric scattering sky from space artifacts

    - by ollipekka
    I am in the process of implementing atmospheric scattering of a planets from space. I have been using Sean O'Neil's shaders from http://http.developer.nvidia.com/GPUGems2/gpugems2_chapter16.html as a starting point. I have pretty much the same problem related to fCameraAngle except with SkyFromSpace shader as opposed to GroundFromSpace shader as here: http://www.gamedev.net/topic/621187-sean-oneils-atmospheric-scattering/ I get strange artifacts with sky from space shader when not using fCameraAngle = 1 in the inner loop. What is the cause of these artifacts? The artifacts disappear when fCameraAngle is limtied to 1. I also seem to lack the hue that is present in O'Neil's sandbox (http://sponeil.net/downloads.htm) Camera position X=0, Y=0, Z=500. GroundFromSpace on the left, SkyFromSpace on the right. Camera position X=500, Y=500, Z=500. GroundFromSpace on the left, SkyFromSpace on the right. I've found that the camera angle seems to handled very differently depending the source: In the original shaders the camera angle in SkyFromSpaceShader is calculated as: float fCameraAngle = dot(v3Ray, v3SamplePoint) / fHeight; Whereas in ground from space shader the camera angle is calculated as: float fCameraAngle = dot(-v3Ray, v3Pos) / length(v3Pos); However, various sources online tinker with negating the ray. Why is this? Here is a C# Windows.Forms project that demonstrates the problem and that I've used to generate the images: https://github.com/ollipekka/AtmosphericScatteringTest/ Update: I have found out from the ScatterCPU project found on O'Neil's site that the camera ray is negated when the camera is above the point being shaded so that the scattering is calculated from point to the camera. Changing the ray direction indeed does remove artifacts, but introduces other problems as illustrated here: Furthermore, in the ScatterCPU project, O'Neil guards against situations where optical depth for light is less than zero: float fLightDepth = Scale(fLightAngle, fScaleDepth); if (fLightDepth < float.Epsilon) { continue; } As pointed out in the comments, along with these new artifacts this still leaves the question, what is wrong with the images where camera is positioned at 500, 500, 500? It feels like the halo is focused on completely wrong part of the planet. One would expect that the light would be closer to the spot where the sun should hits the planet, rather than where it changes from day to night. The github project has been updated to reflect changes in this update.

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  • How to fix OpenGL Co-ordinate System in SFML?

    - by Marc Alexander Reed
    My OpenGL setup is somehow configured to work like so: (-1, 1) (0, 1) (1, 1) (-1, 0) (0, 0) (1, 0) (-1, -1) (0, -1) (1, -1) How do I configure it so that it works like so: (0, 0) (SW/2, 0) (SW, 0) (0, SH/2) (SW/2, SH/2) (SW, SH/2) (0, SH) (SW/2, SH) (SW/2, SH) SW as Screen Width. SH as Screen Height. This solution would have to fix the problem of I can't translate significantly(1) on the Z axis. Depth doesn't seem to be working either. The Perspective code I'm using is that of my WORKING GLUT OpenGL code which has a cool 3d grid and camera system etc. But my OpenGL setup doesn't seem to work with SFML. Help me guys. :( Thanks in advance. :) #include <SFML/Window.hpp> #include <SFML/Graphics.hpp> #include <SFML/Audio.hpp> #include <SFML/Network.hpp> #include <SFML/OpenGL.hpp> #include "ResourcePath.hpp" //Mac-only #define _USE_MATH_DEFINES #include <cmath> double screen_width = 640.f; double screen_height = 480.f; int main (int argc, const char **argv) { sf::ContextSettings settings; settings.depthBits = 24; settings.stencilBits = 8; settings.antialiasingLevel = 2; sf::Window window(sf::VideoMode(screen_width, screen_height, 32), "SFML OpenGL", sf::Style::Close, settings); window.setActive(); glEnable(GL_DEPTH_TEST); glEnable(GL_LIGHTING); glEnable(GL_LIGHT0); glEnable(GL_NORMALIZE); glEnable(GL_COLOR_MATERIAL); glShadeModel(GL_SMOOTH); glViewport(0, 0, screen_width, screen_height); glMatrixMode(GL_PROJECTION); glLoadIdentity(); //glOrtho(0.0f, screen_width, screen_height, 0.0f, -100.0f, 100.0f); gluPerspective(45.0f, (double) screen_width / (double) screen_height , 0.f, 100.f); glClearColor(0.f, 0.f, 1.f, 0.f); //blue while (window.isOpen()) { sf::Event event; while (window.pollEvent(event)) { switch (event.type) { case sf::Event::Closed: window.close(); break; } switch (event.key.code) { case sf::Keyboard::Escape: window.close(); break; case 'W': break; case 'S': break; case 'A': break; case 'D': break; } } glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); glMatrixMode(GL_MODELVIEW); glLoadIdentity(); glTranslatef(0.f, 0.f, 0.f); glPushMatrix(); glBegin(GL_QUADS); glColor3f(1.f, 0.f, 0.f); glVertex3f(-1.f, 1.f, 0.f); glColor3f(0.f, 1.f, 0.f); glVertex3f(1.f, 1.f, 0.f); glColor3f(1.f, 0.f, 1.f); glVertex3f(1.f, -1.f, 0.f); glColor3f(0.f, 0.f, 1.f); glVertex3f(-1.f, -1.f, 0.f); glEnd(); glPopMatrix(); window.display(); } return EXIT_SUCCESS; }

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  • Setting effects variables in XNA

    - by Badescu Alexandru
    Hello ! I am currently reading a book named "3D Graphics with XNA Game Studio 4.0" by Sean James and have some questions to ask : If i create a effect parameter named lets say SpecularPower and have in my effect a variable named SpecularPower , if i do something like effect.Parameters["SpecularPower"].SetValue(3) That wil change the SpecularPower variable in my effect ? And a second question, not regarding the book : If i have a spaceship and i've created a "boost" functionality that speeds up my spaceship, what effects should i implement to create the impresion oh high speed ? I was thinking of making everything except my spaceship blurry but i think there would be something missing . Any ideas ? Regards, Alex Badescu

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  • What is a better abstraction layer for D3D9 and OpenGL vertex data management?

    - by Sam Hocevar
    My rendering code has always been OpenGL. I now need to support a platform that does not have OpenGL, so I have to add an abstraction layer that wraps OpenGL and Direct3D 9. I will support Direct3D 11 later. TL;DR: the differences between OpenGL and Direct3D cause redundancy for the programmer, and the data layout feels flaky. For now, my API works a bit like this. This is how a shader is created: Shader *shader = Shader::Create( " ... GLSL vertex shader ... ", " ... GLSL pixel shader ... ", " ... HLSL vertex shader ... ", " ... HLSL pixel shader ... "); ShaderAttrib a1 = shader->GetAttribLocation("Point", VertexUsage::Position, 0); ShaderAttrib a2 = shader->GetAttribLocation("TexCoord", VertexUsage::TexCoord, 0); ShaderAttrib a3 = shader->GetAttribLocation("Data", VertexUsage::TexCoord, 1); ShaderUniform u1 = shader->GetUniformLocation("WorldMatrix"); ShaderUniform u2 = shader->GetUniformLocation("Zoom"); There is already a problem here: once a Direct3D shader is compiled, there is no way to query an input attribute by its name; apparently only the semantics stay meaningful. This is why GetAttribLocation has these extra arguments, which get hidden in ShaderAttrib. Now this is how I create a vertex declaration and two vertex buffers: VertexDeclaration *decl = VertexDeclaration::Create( VertexStream<vec3,vec2>(VertexUsage::Position, 0, VertexUsage::TexCoord, 0), VertexStream<vec4>(VertexUsage::TexCoord, 1)); VertexBuffer *vb1 = new VertexBuffer(NUM * (sizeof(vec3) + sizeof(vec2)); VertexBuffer *vb2 = new VertexBuffer(NUM * sizeof(vec4)); Another problem: the information VertexUsage::Position, 0 is totally useless to the OpenGL/GLSL backend because it does not care about semantics. Once the vertex buffers have been filled with or pointed at data, this is the rendering code: shader->Bind(); shader->SetUniform(u1, GetWorldMatrix()); shader->SetUniform(u2, blah); decl->Bind(); decl->SetStream(vb1, a1, a2); decl->SetStream(vb2, a3); decl->DrawPrimitives(VertexPrimitive::Triangle, NUM / 3); decl->Unbind(); shader->Unbind(); You see that decl is a bit more than just a D3D-like vertex declaration, it kinda takes care of rendering as well. Does this make sense at all? What would be a cleaner design? Or a good source of inspiration?

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  • Using idle time in turn-based (RPG) games for updating

    - by The Communist Duck
    If you take any turn based RPG game there will be large periods of time when nothing is happening because the game is looping over 'wait_for_player_input'. Naturally it seems sensible to use this time to update things. However, this immediately seems to suggest that it would need to be threaded. Is this sort of design possible in a single thread? loop: if not check_something_pressed: update_a_very_small_amount else keep going But if we says 'a_very_small_amount' is only updating a single object each loop, it's going to be very slow at updating. How would you go about this, preferably in a single thread? EDIT: I've tagged this language-agnostic as that seems the sensible thing, though anything more specific to Python would be great. ;-)

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  • xna download website source code

    - by Emre Canbazoglu
    I have to download the html code of a web site during the game. I am taking the poster url of a movie from the imdb web site by scrapping the html ( also other informations ). I have to do the download process many times during the game for different movies. I can download and scrap the html but downloading the html takes too much time and it causes the game to slow down(freeze while downloading). How can I solve this problem? My one approach is to download and scrap all the information and store them in a database before the game and during the game access this information from the database. I think this will work properly but that is not what I exactly want. It would be better if it is dynamic. I also thought of using multi-threading but I am a bit confused about how to implement threading in xna. I read some articles about it but it is not so clear. I mean when should I start the thread and what about the update function etc. I need your help guys

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  • Index out of bounds, Java bukkit plugin

    - by Robby Duke
    I'm getting index out of bounds errors in my Bukkit plugin, and it's really beginning to piss me off... I for the life of me can't figure this issue out! Caused by: java.lang.IndexOutOfBoundsException: Index: 1, Size: 1 This is where I believe the code to be erroring... for(int i = 0; i <= staffOnline.size(); i++) { if(i == staffOnline.size()) { staffList = staffList + staffOnline.get(i); } else { staffList = staffList + staffOnline.get(i) + ", "; } }

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  • XNA Masking Mayhem

    - by TropicalFlesh
    I'd like to start by mentioning that I'm just an amateur programmer of the past 2 years with no formal training and know very little about maximizing the potential of graphics hardware. I can write shaders and manipulate a multi-layered drawing environment, but I've basically stuck to minimalist pixel shaders. I'm working on putting dynamic point light shadows in my 2d sidescroller, and have had it working to a reasonable degree. Just chucking it in without working on serious optimizations outside of basic culling, I can get 50 lights or so onscreen at once and still hover around 100 fps. The only issue is that I'm on a very high end machine and would like to target the game at as many platforms I can, low and high end. The way I'm doing shadows involves a lot of masking before I can finally draw the light to my light layer. Basically, my technique to achieveing such shadows is as follows. See pics in this album http://imgur.com/a/m2fWw#0 The dark gray represents the background tiles, the light gray represents the foreground tiles, and the yellow represents the shadow-emitting foreground tile. I'll draw the light using a radial gradient and a color of choice I'll then exclude light from the mask by drawing some geometry extending through the tile from my point light. I actually don't mask the light yet at this point, but I'm just illustrating the technique in this image Finally, I'll re-include the foreground layer in my mask, as I only want shadows to collect on the background layer and finally multiply the light with it's mask to the light layer My question is simple - How can I go about reducing the amount of render target switches I need to do to achieve the following: a. Draw mask to exclude shadows from the foreground to it's own target once per frame b. For each light that emits shadows, -Begin light mask as full white -Render shadow geometry as transparent with an opaque blendmode to eliminate shadowed areas from the mask -Render foreground mask back over the light mask to reintroduce light to the foreground c. Multiply light texture with it's individual mask to the main light layer.

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  • JOGL hardware based shadow mapping - computing the texture matrix

    - by axel22
    I am implementing hardware shadow mapping as described here. I've rendered the scene successfully from the light POV, and loaded the depth buffer of the scene into a texture. This texture has correctly been loaded - I check this by rendering a small thumbnail, as you can see in the screenshot below, upper left corner. The depth of the scene appears to be correct - objects further away are darker, and that are closer to the light are lighter. However, I run into trouble while rendering the scene from the camera's point of view using the depth texture - the texture on the polygons in the scene is rendered in a weird, nondeterministic fashion, as shown in the screenshot. I believe I am making an error while computing the texture transformation matrix, but I am unsure where exactly. Since I have no matrix utilities in JOGL other then the gl[Load|Mult]Matrix procedures, I multiply the matrices using them, like this: void calcTextureMatrix() { glPushMatrix(); glLoadIdentity(); glLoadMatrixf(biasmatrix, 0); glMultMatrixf(lightprojmatrix, 0); glMultMatrixf(lightviewmatrix, 0); glGetFloatv(GL_MODELVIEW_MATRIX, shadowtexmatrix, 0); glPopMatrix(); } I obtained these matrices by using the glOrtho and gluLookAt procedures: glLoadIdentity() val wdt = width / 45 val hgt = height / 45 glOrtho(wdt, -wdt, -hgt, hgt, -45.0, 45.0) glGetFloatv(GL_MODELVIEW_MATRIX, lightprojmatrix, 0) glLoadIdentity() glu.gluLookAt( xlook + lightpos._1, ylook + lightpos._2, lightpos._3, xlook, ylook, 0.0f, 0.f, 0.f, 1.0f) glGetFloatv(GL_MODELVIEW_MATRIX, lightviewmatrix, 0) My bias matrix is: float[] biasmatrix = new float[16] { 0.5f, 0.f, 0.f, 0.f, 0.f, 0.5f, 0.f, 0.f, 0.f, 0.f, 0.5f, 0.f, 0.5f, 0.5f, 0.5f, 1.f } After applying the camera projection and view matrices, I do: glTexGeni(GL_S, GL_TEXTURE_GEN_MODE, GL_EYE_LINEAR) glTexGenfv(GL_S, GL_EYE_PLANE, shadowtexmatrix, 0) glEnable(GL_TEXTURE_GEN_S) for each component. Does anybody know why the texture is not being rendered correctly? Thank you.

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  • Derive a algorithm to match best position

    - by Farooq Arshed
    I have pieces in my game which have stats and cost assigned to them and they can only be placed at a certain location. Lets say I have 50 pieces. e.g. Piece1 = 100 stats, 10 cost, Position A. Piece2 = 120 stats, 5 cost, Position B. Piece3 = 500 stats, 50 cost, Position C. Piece4 = 200 stats, 25 cost, Position A. and so on.. I have a board on which 12 pieces have to be allocated and have to remain inside the board cost. e.g. A board has A,B,C ... J,K,L positions and X Cost assigned to it. I have to figure out a way to place best possible piece in the correct position and should remain within the cost specified by the board. Any help would be appreciated.

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  • Making an AI walk on a NavigationMesh (2D/Top-Down game)

    - by Lennard Fonteijn
    For some time I have been working on a framework which should make it possible to generate 2D levels based on a set of rules specified by level designers. You can read more about it here as I won't go into details: http://www.jorisdormans.nl/article.php?ref=engineering_emergence Anyway, I'm now at the point of putting the framework to use and have trouble coming up with a solution for AI. I decided to implement a NavigationMesh in the generated levels as I already have that information to start with. Consider the following image (borrowed from http://www.david-gouveia.com/pathfinding-on-a-2d-polygonal-map/): When I run A* on the NavigationMesh, the red path would be suggested when I want to go from point A to B (either direction). However, I don't want my AI to walk that path directly and clipping corners, I'd rather want them to follow the more logical black path. How would I go about going from the Red path to the Black path, are there any algorithms for this. Which steps do I take? Is A* the proper solution for this at all? For some additional information: The proof-of-concept game is a 2D top-down game written in C#, but examples/references in any language are welcome!

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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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  • Off center projection

    - by N0xus
    I'm trying to implement the code that was freely given by a very kind developer at the following link: http://forum.unity3d.com/threads/142383-Code-sample-Off-Center-Projection-Code-for-VR-CAVE-or-just-for-fun Right now, all I'm trying to do is bring it in on one camera, but I have a few issues. My class, looks as follows: using UnityEngine; using System.Collections; public class PerspectiveOffCenter : MonoBehaviour { // Use this for initialization void Start () { } // Update is called once per frame void Update () { } public static Matrix4x4 GeneralizedPerspectiveProjection(Vector3 pa, Vector3 pb, Vector3 pc, Vector3 pe, float near, float far) { Vector3 va, vb, vc; Vector3 vr, vu, vn; float left, right, bottom, top, eyedistance; Matrix4x4 transformMatrix; Matrix4x4 projectionM; Matrix4x4 eyeTranslateM; Matrix4x4 finalProjection; ///Calculate the orthonormal for the screen (the screen coordinate system vr = pb - pa; vr.Normalize(); vu = pc - pa; vu.Normalize(); vn = Vector3.Cross(vr, vu); vn.Normalize(); //Calculate the vector from eye (pe) to screen corners (pa, pb, pc) va = pa-pe; vb = pb-pe; vc = pc-pe; //Get the distance;; from the eye to the screen plane eyedistance = -(Vector3.Dot(va, vn)); //Get the varaibles for the off center projection left = (Vector3.Dot(vr, va)*near)/eyedistance; right = (Vector3.Dot(vr, vb)*near)/eyedistance; bottom = (Vector3.Dot(vu, va)*near)/eyedistance; top = (Vector3.Dot(vu, vc)*near)/eyedistance; //Get this projection projectionM = PerspectiveOffCenter(left, right, bottom, top, near, far); //Fill in the transform matrix transformMatrix = new Matrix4x4(); transformMatrix[0, 0] = vr.x; transformMatrix[0, 1] = vr.y; transformMatrix[0, 2] = vr.z; transformMatrix[0, 3] = 0; transformMatrix[1, 0] = vu.x; transformMatrix[1, 1] = vu.y; transformMatrix[1, 2] = vu.z; transformMatrix[1, 3] = 0; transformMatrix[2, 0] = vn.x; transformMatrix[2, 1] = vn.y; transformMatrix[2, 2] = vn.z; transformMatrix[2, 3] = 0; transformMatrix[3, 0] = 0; transformMatrix[3, 1] = 0; transformMatrix[3, 2] = 0; transformMatrix[3, 3] = 1; //Now for the eye transform eyeTranslateM = new Matrix4x4(); eyeTranslateM[0, 0] = 1; eyeTranslateM[0, 1] = 0; eyeTranslateM[0, 2] = 0; eyeTranslateM[0, 3] = -pe.x; eyeTranslateM[1, 0] = 0; eyeTranslateM[1, 1] = 1; eyeTranslateM[1, 2] = 0; eyeTranslateM[1, 3] = -pe.y; eyeTranslateM[2, 0] = 0; eyeTranslateM[2, 1] = 0; eyeTranslateM[2, 2] = 1; eyeTranslateM[2, 3] = -pe.z; eyeTranslateM[3, 0] = 0; eyeTranslateM[3, 1] = 0; eyeTranslateM[3, 2] = 0; eyeTranslateM[3, 3] = 1f; //Multiply all together finalProjection = new Matrix4x4(); finalProjection = Matrix4x4.identity * projectionM*transformMatrix*eyeTranslateM; //finally return return finalProjection; } // Update is called once per frame public void FixedUpdate () { Camera cam = camera; //calculate projection Matrix4x4 genProjection = GeneralizedPerspectiveProjection( new Vector3(0,1,0), new Vector3(1,1,0), new Vector3(0,0,0), new Vector3(0,0,0), cam.nearClipPlane, cam.farClipPlane); //(BottomLeftCorner, BottomRightCorner, TopLeftCorner, trackerPosition, cam.nearClipPlane, cam.farClipPlane); cam.projectionMatrix = genProjection; } } My error lies in projectionM = PerspectiveOffCenter(left, right, bottom, top, near, far); The debugger states: Expression denotes a `type', where a 'variable', 'value' or 'method group' was expected. Thus, I changed the line to read: projectionM = new PerspectiveOffCenter(left, right, bottom, top, near, far); But then the error is changed to: The type 'PerspectiveOffCenter' does not contain a constructor that takes '6' arguments. For reasons that are obvious. So, finally, I changed the line to read: projectionM = new GeneralizedPerspectiveProjection(left, right, bottom, top, near, far); And the error I get is: is a 'method' but a 'type' was expected. With this last error, I'm not sure what it is I should do / missing. Can anyone see what it is that I'm missing to fix this error?

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  • Sliding collision response

    - by dbostream
    I have been reading plenty of tutorials about sliding collision responses yet I am not able to implement it properly in my project. What I want to do is make a puck slide along the rounded corner boards of a hockey rink. In my latest attempt the puck does slide along the boards but there are some strange velocity behaviors. First of all the puck slows down a lot pretty much right away and then it slides for awhile and stops before exiting the corner. Even if I double the speed I get a similar behavior and the puck does not make it out of the corner. I used some ideas from this document http://www.peroxide.dk/papers/collision/collision.pdf. This is what I have: Update method called from the game loop when it is time to update the puck (I removed some irrelevant parts). I use two states (current, previous) which are used to interpolate the position during rendering. public override void Update(double fixedTimeStep) { /* Acceleration is set to 0 for now. */ Acceleration.Zero(); PreviousState = CurrentState; _collisionRecursionDepth = 0; CurrentState.Position = SlidingCollision(CurrentState.Position, CurrentState.Velocity * fixedTimeStep + 0.5 * Acceleration * fixedTimeStep * fixedTimeStep); /* Should not this be affected by a sliding collision? and not only the position. */ CurrentState.Velocity = CurrentState.Velocity + Acceleration * fixedTimeStep; Heading = Vector2.NormalizeRet(CurrentState.Velocity); } private Vector2 SlidingCollision(Vector2 position, Vector2 velocity) { if(_collisionRecursionDepth > 5) return position; bool collisionFound = false; Vector2 futurePosition = position + velocity; Vector2 intersectionPoint = new Vector2(); Vector2 intersectionPointNormal = new Vector2(); /* I did not include the collision detection code, if a collision is detected the intersection point and normal in that point is returned. */ if(!collisionFound) return futurePosition; /* If no collision was detected it is safe to move to the future position. */ /* It is not exactly the intersection point, but slightly before. */ Vector2 newPosition = intersectionPoint; /* oldVelocity is set to the distance from the newPosition(intersection point) to the position it had moved to had it not collided. */ Vector2 oldVelocity = futurePosition - newPosition; /* Project the distance left to move along the intersection normal. */ Vector2 newVelocity = oldVelocity - intersectionPointNormal * oldVelocity.DotProduct(intersectionPointNormal); if(newVelocity.LengthSq() < 0.001) return newPosition; /* If almost no speed, no need to continue. */ _collisionRecursionDepth++; return SlidingCollision(newPosition, newVelocity); } What am I doing wrong with the velocity? I have been staring at this for very long so I have gone blind. I have tried different values of recursion depth but it does not seem to make it better. Let me know if you need more information. I appreciate any help. EDIT: A combination of Patrick Hughes' and teodron's answers solved the velocity problem (I think), thanks a lot! This is the new code: I decided to use a separate recursion method now too since I don't want to recalculate the acceleration in each recursion. public override void Update(double fixedTimeStep) { Acceleration.Zero();// = CalculateAcceleration(fixedTimeStep); PreviousState = new MovingEntityState(CurrentState.Position, CurrentState.Velocity); CurrentState = SlidingCollision(CurrentState, fixedTimeStep); Heading = Vector2.NormalizeRet(CurrentState.Velocity); } private MovingEntityState SlidingCollision(MovingEntityState state, double timeStep) { bool collisionFound = false; /* Calculate the next position given no detected collision. */ Vector2 futurePosition = state.Position + state.Velocity * timeStep; Vector2 intersectionPoint = new Vector2(); Vector2 intersectionPointNormal = new Vector2(); /* I did not include the collision detection code, if a collision is detected the intersection point and normal in that point is returned. */ /* If no collision was detected it is safe to move to the future position. */ if (!collisionFound) return new MovingEntityState(futurePosition, state.Velocity); /* Set new position to the intersection point (slightly before). */ Vector2 newPosition = intersectionPoint; /* Project the new velocity along the intersection normal. */ Vector2 newVelocity = state.Velocity - 1.90 * intersectionPointNormal * state.Velocity.DotProduct(intersectionPointNormal); /* Calculate the time of collision. */ double timeOfCollision = Math.Sqrt((newPosition - state.Position).LengthSq() / (futurePosition - state.Position).LengthSq()); /* Calculate new time step, remaining time of full step after the collision * current time step. */ double newTimeStep = timeStep * (1 - timeOfCollision); return SlidingCollision(new MovingEntityState(newPosition, newVelocity), newTimeStep); } Even though the code above seems to slide the puck correctly please have a look at it. I have a few questions, if I don't multiply by 1.90 in the newVelocity calculation it doesn't work (I get a stack overflow when the puck enters the corner because the timeStep decreases very slowly - a collision is found early in every recursion), why is that? what does 1.90 really do and why 1.90? Also I have a new problem, the puck does not move parallell to the short side after exiting the curve; to be more exact it moves outside the rink (I am not checking for any collisions with the short side at the moment). When I perform the collision detection I first check that the puck is in the correct quadrant. For example bottom-right corner is quadrant four i.e. circleCenter.X < puck.X && circleCenter.Y puck.Y is this a problem? or should the short side of the rink be the one to make the puck go parallell to it and not the last collision in the corner? EDIT2: This is the code I use for collision detection, maybe it has something to do with the fact that I can't make the puck slide (-1.0) but only reflect (-2.0): /* Point is the current position (not the predicted one) and quadrant is 4 for the bottom-right corner for example. */ if (GeometryHelper.PointInCircleQuadrant(circleCenter, circleRadius, state.Position, quadrant)) { /* The line is: from = state.Position, to = futurePosition. So a collision is detected when from is inside the circle and to is outside. */ if (GeometryHelper.LineCircleIntersection2d(state.Position, futurePosition, circleCenter, circleRadius, intersectionPoint, quadrant)) { collisionFound = true; /* Set the intersection point to slightly before the real intersection point (I read somewhere this was good to do because of floting point precision, not sure exactly how much though). */ intersectionPoint = intersectionPoint - Vector2.NormalizeRet(state.Velocity) * 0.001; /* Normal at the intersection point. */ intersectionPointNormal = Vector2.NormalizeRet(circleCenter - intersectionPoint) } } When I set the intersection point, if I for example use 0.1 instead of 0.001 the puck travels further before it gets stuck, but for all values I have tried (including 0 - the real intersection point) it gets stuck somewhere (but I necessarily not get a stack overflow). Can something in this part be the cause of my problem? I can see why I get the stack overflow when using -1.0 when calculating the new velocity vector; but not how to solve it. I traced the time steps used in the recursion (initial time step is always 1/60 ~ 0.01666): Recursion depth Time step next recursive call [Start recursion, time step ~ 0.016666] 0 0,000985806527246773 [No collision, stop recursion] [Start recursion, time step ~ 0.016666] 0 0,0149596704364629 1 0,0144883449376379 2 0,0143155612984837 3 0,014224925727213 4 0,0141673917461608 5 0,0141265435314026 6 0,0140953966184117 7 0,0140704653746625 ...and so on. As you can see the collision is detected early in every recursive call which means the next time step decreases very slowly thus the recursion depth gets very big - stack overflow.

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  • Using virtual functions

    - by Tucker Morgan
    I am starting to use virtual functions, and i am programming a simple text game, my question is this, if i have a virtual function called spec_abil with in a Super class called rpg_class. If you allow the player to class what class they want to play, say a mage class, a archer class, and a warrior class, which all have their own spec_abil function. How do you write it so that the program knows which one to use depending on the chosen class.

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  • as3 3D camera lookat

    - by Johannes Jensen
    I'm making a 3D camera scene in Flash, draw using drawTriangles() and rotated and translated using a Matrix3D. I've got the camera to look after a specific point, but only on the Y-axis, using the x and z coordinates, here is my code so far: var dx:Number = camera.x - lookAt.x; var dy:Number = camera.y - lookAt.y; var dz:Number = camera.z - lookAt.z; camera.rotationY = Math.atan2(dz, dx) * (180 / Math.PI) + 270; so no matter the x or z position, the point is always on the mid of the screen, IF and only if y matches with the camera. So what I need is to calculate the rotationX (which are measured in degrees not radians), and I was wondering how I would do this?

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  • Normal maps red in OpenGL?

    - by KaiserJohaan
    I am using Assimp to import 3d models, and FreeImage to parse textures. The problem I am having is that the normal maps are actually red rather than blue when I try to render them as normal diffuse textures. http://i42.tinypic.com/289ing3.png When I open the images in a image-viewing program they do indeed show up as blue. Heres when I create the texture; OpenGLTexture::OpenGLTexture(const std::vector<uint8_t>& textureData, uint32_t textureWidth, uint32_t textureHeight, TextureType textureType, Logger& logger) : mLogger(logger), mTextureID(gNextTextureID++), mTextureType(textureType) { glGenTextures(1, &mTexture); CHECK_GL_ERROR(mLogger); glBindTexture(GL_TEXTURE_2D, mTexture); CHECK_GL_ERROR(mLogger); glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, textureWidth, textureHeight, 0, glTextureFormat, GL_UNSIGNED_BYTE, &textureData[0]); CHECK_GL_ERROR(mLogger); glGenerateMipmap(GL_TEXTURE_2D); CHECK_GL_ERROR(mLogger); glBindTexture(GL_TEXTURE_2D, 0); CHECK_GL_ERROR(mLogger); } Here is my fragment shader. You can see I just commented out the normal-map parsing and treated the normal map texture as the diffuse texture to display it and illustrate the problem. As for the rest of the code it interacts as expected with the diffuse textures so I dont see a obvious problem there. "#version 330 \n \ \n \ layout(std140) uniform; \n \ \n \ const int MAX_LIGHTS = 8; \n \ \n \ struct Light \n \ { \n \ vec4 mLightColor; \n \ vec4 mLightPosition; \n \ vec4 mLightDirection; \n \ \n \ int mLightType; \n \ float mLightIntensity; \n \ float mLightRadius; \n \ float mMaxDistance; \n \ }; \n \ \n \ uniform UnifLighting \n \ { \n \ vec4 mGamma; \n \ vec3 mViewDirection; \n \ int mNumLights; \n \ \n \ Light mLights[MAX_LIGHTS]; \n \ } Lighting; \n \ \n \ uniform UnifMaterial \n \ { \n \ vec4 mDiffuseColor; \n \ vec4 mAmbientColor; \n \ vec4 mSpecularColor; \n \ vec4 mEmissiveColor; \n \ \n \ bool mHasDiffuseTexture; \n \ bool mHasNormalTexture; \n \ bool mLightingEnabled; \n \ float mSpecularShininess; \n \ } Material; \n \ \n \ uniform sampler2D unifDiffuseTexture; \n \ uniform sampler2D unifNormalTexture; \n \ \n \ in vec3 frag_position; \n \ in vec3 frag_normal; \n \ in vec2 frag_texcoord; \n \ in vec3 frag_tangent; \n \ in vec3 frag_bitangent; \n \ \n \ out vec4 finalColor; " " \n \ \n \ void CalcGaussianSpecular(in vec3 dirToLight, in vec3 normal, out float gaussianTerm) \n \ { \n \ vec3 viewDirection = normalize(Lighting.mViewDirection); \n \ vec3 halfAngle = normalize(dirToLight + viewDirection); \n \ \n \ float angleNormalHalf = acos(dot(halfAngle, normalize(normal))); \n \ float exponent = angleNormalHalf / Material.mSpecularShininess; \n \ exponent = -(exponent * exponent); \n \ \n \ gaussianTerm = exp(exponent); \n \ } \n \ \n \ vec4 CalculateLighting(in Light light, in vec4 diffuseTexture, in vec3 normal) \n \ { \n \ if (light.mLightType == 1) // point light \n \ { \n \ vec3 positionDiff = light.mLightPosition.xyz - frag_position; \n \ float dist = max(length(positionDiff) - light.mLightRadius, 0); \n \ \n \ float attenuation = 1 / ((dist/light.mLightRadius + 1) * (dist/light.mLightRadius + 1)); \n \ attenuation = max((attenuation - light.mMaxDistance) / (1 - light.mMaxDistance), 0); \n \ \n \ vec3 dirToLight = normalize(positionDiff); \n \ float angleNormal = clamp(dot(normalize(normal), dirToLight), 0, 1); \n \ \n \ float gaussianTerm = 0.0; \n \ if (angleNormal > 0.0) \n \ CalcGaussianSpecular(dirToLight, normal, gaussianTerm); \n \ \n \ return diffuseTexture * (attenuation * angleNormal * Material.mDiffuseColor * light.mLightIntensity * light.mLightColor) + \n \ (attenuation * gaussianTerm * Material.mSpecularColor * light.mLightIntensity * light.mLightColor); \n \ } \n \ else if (light.mLightType == 2) // directional light \n \ { \n \ vec3 dirToLight = normalize(light.mLightDirection.xyz); \n \ float angleNormal = clamp(dot(normalize(normal), dirToLight), 0, 1); \n \ \n \ float gaussianTerm = 0.0; \n \ if (angleNormal > 0.0) \n \ CalcGaussianSpecular(dirToLight, normal, gaussianTerm); \n \ \n \ return diffuseTexture * (angleNormal * Material.mDiffuseColor * light.mLightIntensity * light.mLightColor) + \n \ (gaussianTerm * Material.mSpecularColor * light.mLightIntensity * light.mLightColor); \n \ } \n \ else if (light.mLightType == 4) // ambient light \n \ return diffuseTexture * Material.mAmbientColor * light.mLightIntensity * light.mLightColor; \n \ else \n \ return vec4(0.0); \n \ } \n \ \n \ void main() \n \ { \n \ vec4 diffuseTexture = vec4(1.0); \n \ if (Material.mHasDiffuseTexture) \n \ diffuseTexture = texture(unifDiffuseTexture, frag_texcoord); \n \ \n \ vec3 normal = frag_normal; \n \ if (Material.mHasNormalTexture) \n \ { \n \ diffuseTexture = vec4(normalize(texture(unifNormalTexture, frag_texcoord).xyz * 2.0 - 1.0), 1.0); \n \ // vec3 normalTangentSpace = normalize(texture(unifNormalTexture, frag_texcoord).xyz * 2.0 - 1.0); \n \ //mat3 tangentToWorldSpace = mat3(normalize(frag_tangent), normalize(frag_bitangent), normalize(frag_normal)); \n \ \n \ // normal = tangentToWorldSpace * normalTangentSpace; \n \ } \n \ \n \ if (Material.mLightingEnabled) \n \ { \n \ vec4 accumLighting = vec4(0.0); \n \ \n \ for (int lightIndex = 0; lightIndex < Lighting.mNumLights; lightIndex++) \n \ accumLighting += Material.mEmissiveColor * diffuseTexture + \n \ CalculateLighting(Lighting.mLights[lightIndex], diffuseTexture, normal); \n \ \n \ finalColor = pow(accumLighting, Lighting.mGamma); \n \ } \n \ else { \n \ finalColor = pow(diffuseTexture, Lighting.mGamma); \n \ } \n \ } \n"; Why is this? does normal-map textures need some sort of special treatment in opengl?

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  • How to slow down a sprite that updates every frame?

    - by xiaohouzi79
    I am going through a Allegro 5 tutorial which has a game loop. There is also a variable "active" which determines if a key is being held down. Thus if the left key is being held down active is on and it begins looping through the row on the sprite sheet that corresponds to moving left. The problem is that this logic is checked everytime the loop is performed thus at approximately 60 fps the three images that are used to do the left walking animation cycle round super fast which means my character looks like it is in a rush. Total beginner question: so what is the correct way to slow down the transition between sprites so that the walking looks like it is done at a moderate pace. Here is the code used to transition across the sprite between the three different phases of the person walking: if (active) { sourceX += al_get_bitmap_width(player) / 3; } else { sourceX = 32; } if (sourceX >= al_get_bitmap_width(player)) { sourceX = 0; } I can kind of guess what it should be in plain English: update sourceX only every certain part of a second but I can't think of how to put this into code.

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  • Clientside anticheating in multiplayer game 1vs1

    - by garnav
    I'm developing a simple card game, where there will be a matchmaking system that will put you against another human player. This will be the only game mode available, a 1vs1 against another human, no AI. I want to prevent cheating as much as possible. I have already read a lot of similar questions here and I already know that I cannot trust the client and I have to make all verifications server side. I intend to have a server (need one for the matchmaking anyway) and I intend to make some verifications server side but if I want to check everything server side this makes my server to be able to keep track of the state of all current games and check every action, and I don't have the money/infrastructure to support that server. My idea is to make clients check and verify some of the actions made by their opponent* and if they find some illegal action notify the possible cheating to the server and make the server verify it. This will still require my server to keep track of all current games, but it will save resources only checking some things that cannot be checked at client side(like card order in the deck) and only checking other things when they are actually wrong. *(only those they can check with out allowing themselves cheating! for example:they can't check if the played card was in hand cos that will need them to know all cards in hand) Summing up, my questions are: is this a viable approach? will I actually save resources doing this or the extra complexity in the server and client for exchanging this messages is not worth it? do you know any game that has successfully or unsuccessfully tried a similar approach? Thanks all for reading and answering

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  • RenderTarget2D behavior in XNA

    - by Utkarsh Sinha
    I've been dabbling with XNA for a couple of days now. This chunk of code doesn't work as I expect. The goal is to render sprites individually and composite them on another rendertarget. P = RenderTarget2D(with RenderTargetUsage.PreserveContents) D = RenderTarget2D(with RenderTargetUsage.DiscardContents) for all sprites: graphicsDevice.SetRenderTarget(D); <draw sprite i> graphicsDevice.SetRenderTarget(P); <Draw D> graphicsDevice.SetRenderTarget(null); <Draw P> The result I get is - only the last sprite is visible. I'm sure I'm missing some piece of information about RenderTarget2D. Any hints on what that might be? Cross posted from - http://stackoverflow.com/questions/9970349/weird-rendertarget2d-behaviour

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  • How does this game loop actually work?

    - by Nicolai
    I read this playfulJS post, about ray-casting: http://www.playfuljs.com/a-first-person-engine-in-265-lines/ It looks really interested, so I decided to look at his javascript. I am no expert in javascript, so I quickly got lost. It's the game loop "object" that really gets me. I simply don't understand how it works. From the code: function GameLoop() { this.frame = this.frame.bind(this); this.lastTime = 0; this.callback = function() {}; } GameLoop.prototype.start = function(callback) { this.callback = callback; requestAnimationFrame(this.frame); }; GameLoop.prototype.frame = function(time) { var seconds = (time - this.lastTime) / 1000; this.lastTime = time; if (seconds < 0.2) this.callback(seconds); requestAnimationFrame(this.frame); }; var loop = new GameLoop(); loop.start(function frame(seconds) { map.update(seconds); player.update(controls.states, map, seconds); camera.render(player, map); }); Now, what really confuses me here, is this bind stuff and how this actually loops. I am guessing, that if less than 0.2 seconds have passed, since the last time the loop was run, it simply goes back to re-check the time. If more than 0.2 seconds have passed, it leaves the frame function, and executes the 3 lines in the loop. But, if this is true, then how does the loop.start() get called again? And what on earth is the meaning of this.frame = this.frame.bind(this);? I've looked up prototypes bind() but I really don't understand it.

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  • Approaches to timed puzzle elements

    - by ndg
    I'm working on a side scrolling game that has a number of timed puzzle elements. As a simple example: I have a number of moving platforms that have been setup to transition in a pattern. Ideally I'd like to ensure that as the player first approaches them, they are in an ideal state -- whereby the player can witness the full transition and more experienced players (i.e: speedrunners) can complete the puzzle immediately without having to wait for the current transition to complete. The issue here, in a nutshell, is that because these platforms begin transitioning at the start of the level, it's impossible to correctly calculate when the player is likely to stumble upon them. I've done a fair bit of Googling but haven't managed to turn up any decent resources with regards to solving a problem like this. The obvious solution is to only begin updating the objects when the player (or more likely: the camera) first encounters them. But this becomes difficult when you consider more complicated situations. It seems like potentially the easiest way of handling this is to have an invisible trigger volume that will tell any puzzle elements located inside of it that the player has 'arrived' upon first colliding with the player. But this would mean I'd have to logically group puzzle elements, which could become fairly messy in a hurry. Take, for instance, a puzzle that appears to the right of the screen. It may take the player a number of seconds to reach it. It would look strange if the elements involved were to remain stationary. But by the time the player arrives, it's likely things will be 'out of sync'. I wanted to post here in the hopes that others know of, or have implemented, a decent solution to this problem?

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