Search Results

Search found 25952 results on 1039 pages for 'development lifecycle'.

Page 387/1039 | < Previous Page | 383 384 385 386 387 388 389 390 391 392 393 394  | Next Page >

  • Inverting matrix then decomposing gives different quaternion than decomposing then inverting the quat

    - by Fraser
    I'm getting different signs when I convert a matrix to quaternion and invert that, versus when I invert a matrix and then get the quaternion from it: Quaternion a = Quaternion.Invert(getRotation(m)); Quaternion b = getRotation(Matrix.Invert(m)); I would expect a and b to be identical (or inverses of each other). However, it looks like q1 = (x, y, -z, -w) while q2 = (-x, -y, w, z). In other words, the Z and W components have been switched for some reason. Note: getRotation() decomposes the transform matrix and returns just the rotation part of it (I've tried normalizing the result; it does nothing). The matrix m is a complete transform matrix and contains a translation (and possibly a scale) as well as a rotation. I'm using D3DXMatrixDecompose to do the actual decomposition.

    Read the article

  • How to I get a rotated sprite to move left or right?

    - by rphello101
    Using Java/Slick 2D, I'm using the mouse to rotate a sprite on the screen and the directional keys (in this case, WASD) to move the spite. Forwards and backwards is easy, just position += cos(ang)*speed or position -= cos(ang)*speed. But how do I get the sprite to move left or right? I'm thinking it has something to do with adding 90 degrees to the angle or something. Any ideas? Rotation code: int mX = Mouse.getX(); int mY = HEIGHT - Mouse.getY(); int pX = sprite.x+sprite.image.getWidth()/2; int pY = sprite.y+sprite.image.getHeight()/2; double mAng; if(mX!=pX){ mAng = Math.toDegrees(Math.atan2(mY - pY, mX - pX)); if(mAng==0 && mX<=pX) mAng=180; } else{ if(mY>pY) mAng=90; else mAng=270; } sprite.angle = mAng; sprite.image.setRotation((float) mAng); And the movement code (delta is change in time): Input input = gc.getInput(); Vector2f direction = new Vector2f(); Vector2f velocity = new Vector2f(); direction.x = (float) Math.cos(Math.toRadians(sprite.angle)); direction.y = (float) Math.sin(Math.toRadians(sprite.angle)); if(direction.length()>0) direction = direction.normalise(); //On a separate note, what does this line of code do? velocity.x = (float) (direction.x * sprite.moveSpeed); velocity.y = (float) (direction.y * sprite.moveSpeed); if(input.isKeyDown(sprite.up)){ sprite.x += velocity.x*delta; sprite.y += velocity.y*delta; }if (input.isKeyDown(sprite.down)){ sprite.x -= velocity.x*delta; sprite.y -= velocity.y*delta; }if (input.isKeyDown(sprite.left)){ //??? }if (input.isKeyDown(sprite.right)){ //??? }

    Read the article

  • Limiting game loop to exactly 60 tics per second (Android / Java)

    - by user22241
    So I'm having terrible problems with stuttering sprites. My rendering and logic takes less than a game tic (16.6667ms) However, although my game loop runs most of the time at 60 ticks per second, it sometimes goes up to 61 - when this happens, the sprites stutter. Currently, my variables used are: //Game updates per second final int ticksPerSecond = 60; //Amount of time each update should take final int skipTicks = (1000 / ticksPerSecond); This is my current game loop @Override public void onDrawFrame(GL10 gl) { // TODO Auto-generated method stub //This method will run continuously //You should call both 'render' and 'update' methods from here //Set curTime initial value if '0' //Set/Re-set loop back to 0 to start counting again loops=0; while(System.currentTimeMillis() > nextGameTick && loops < maxFrameskip){ SceneManager.getInstance().getCurrentScene().updateLogic(); //Time correction to compensate for the missing .6667ms when using int values nextGameTick+=skipTicks; timeCorrection += (1000d/ticksPerSecond) % 1; nextGameTick+=timeCorrection; timeCorrection %=1; //Increase loops loops++; } render(); } I realise that my skipTicks is an int and therefore will come out as 16 rather that 16.6667 However, I tried changing it (and ticksPerSecond) to Longs but got the same problem). I also tried to change the timer used to Nanotime and skiptics to 1000000000/ticksPerSecond, but everything just ran at about 300 ticks per seconds. All I'm attempting to do is to limit my game loop to 60 - what is the best way to guarantee that my game updates never happen at more than 60 times a second? Please note, I do realise that very very old devices might not be able to handle 60 although I really don't expect this to happen - I've tested it on the lowest device I have and it easily achieves 60 tics. So I'm not worried about a device not being able to handle the 60 ticks per second, but rather need to limit it - any help would be appreciated.

    Read the article

  • XNA C# Platformer - physics engine or tile based?

    - by Hugh
    I would like to get some opinions on whether i should develop my game using a physics engine (farseer physics seems to be the best option) or follow the traditional tile-based method. Quick background: - its a college project, my first game, but have 4 years academic programming experience - Just want a basic platformer with a few levels, nothing fancy - want a shooting mechanic, run and gun, just like contra or metal slug for example - possibly some simple puzzles I have made a basic prototype with farseer, the level is hardcoded with collisions and not really tiled, more like big full-screen sized tiles, with collision bodies drawn manually along the ground and walls etc. My main problem is i want a simple retro feel to the jumping and physics but because its a physics simulation engine its going to be realistic, whereas typical in air controllable physics for platformers arent realistic. I have to make a box with wheel body fixture under it to have this effect and its glitchy and doesnt feel right. I chose to use a physics engine because i tried the tile method initially and found it very hard to understand, the engine took care of alot things to save me time, mainly being able to do slopes easily was nice and the freedom to draw collision bounds wherever i liked, rather then restricted to a grid, which gave me more freedom for art design also. In conclusion i don't know which method to pick, i want to use a method which will be the most straight forward way to implement and wont give me a headache later on, preferably a method which has an abundance of tutorials and resources so i dont get "stuck" doing something which has been done a million times before! Let me know i haven't provided enough information for you to help me! Thanks in advance, Hugh.

    Read the article

  • Collision filtering techniques

    - by Griffin
    I was wondering what efficient techniques are out there for mapping collision filtering between various bodies, sub-bodies, and so forth. I'm familiar with the simple idea of having different layers of 2D bodies, but this is not sufficient for more complex mapping: (Think of having sub-bodies of a body, such as limbs, collide with each other by placing them on the same layer, and then wanting to only have the legs collide with the ground while the arms would not) This can be solved with a multidimensional layer setup, but I would probably end up just creating more and more layers to the point where the simplicity and efficiency of layer filtering would be gone. Are there any more complex ways to solve even more complex situations than this?

    Read the article

  • Rotate model using quaternion

    - by ChocoMan
    Currently I have this to rotate my 3D model that rotates on it's local axis independent from the world's axis: // Rotate model with Right Thumbstick modelRotation -= pController.ThumbSticks.Right.X * mRotSpeed; // float value What I'm trying to do is rotate the model using quaternion and not by a matrix. I've searched for tutorials, but have found none that explains thoroughly on how to achieve this. Does anyone know how to I can use quaternions to rotate my model or a complete tutorial?

    Read the article

  • How are these bullets done?

    - by Mike
    I really want to know how the bullets in Radiangames Inferno are done. The bullets seem like they are just billboard particles but I am curious about how their tails are implemented. They can curve so this means they are not just a billboard. Also, they appear continuous which implies that the tails are not made of a bunch of smaller particles (I think). Can anyone shead some light on this for me?

    Read the article

  • convert image to spritesheet of tiles for isometric map?

    - by Paul
    is there a way to convert an isometric image (like the first image) to a spritesheet (like the second image), in order to place each image on the isometric map with the code? The map looks like the first image, but some buildings are bigger than just one tile, so I need several squares (let's say the first image is a building, made of multiple tiles with different colors), and each square is placed with an offset of 64x32. The building is created in Blender and I save the image with the isometric perspective. But I have to split each square from this image in order to have the spritesheet, maybe there is smarter way, or a java software that would make the conversion for me?

    Read the article

  • Rotate/Translate object in local space

    - by Mathias Hölzl
    I am just trying to create a movementcontroller class for game entities. These class should transform the entity affected by the mouse and keyboard input. I am able to calculate the changed rotation and the new globalPosition. Then I multiply: newGlobalMatrix = changedRotationMatrix * oldGlobalMatrix; newGlobalMatrix = MatrixSetPosition(newPosition); The problem is that the object rotates around the global axis and not around the local axis. I use XNAMath for the matrix calculation.

    Read the article

  • How to read BC4 texture in GLSL?

    - by Question
    I'm supposed to receive a texture in BC4 format. In OpenGL, i guess this format is called GL_COMPRESSED_RED_RGTC1. The texture is not really a "texture", more like a data to handle at fragment shader. Usually, to get colors from a texture within a fragment shader, i do : uniform sampler2D TextureUnit; void main() { vec4 TexColor = texture2D(TextureUnit, vec2(gl_TexCoord[0])); (...) the result of which is obviously a v4, for RGBA. But now, i'm supposed to receive a single float from the read. I'm struggling to understand how this is achieved. Should i still use a texture sampler, and expect the value to be in a specific position (for example, within TexColor.r ?), or should i use something else ?

    Read the article

  • When should a bullet texture be loaded in XNA?

    - by Bill
    I'm making a SpaceWar!-esque game using XNA. I want to limit my ships to 5 active bullets at any time. I have a Bullet DrawableGameComponent and a Ship DrawableGameComponent. My Ship has an array of 5 Bullet. What is the best way to manage the Bullet textures? Specifically, when should I be calling LoadTexture? Right now, my solution is to populate the Bullet array in the Ship's constructor, with LoadTexture being called in the Bullet constructor. The Bullet objects will be disabled/not visible except when they are active. Does the texture really need to be loaded once for each individual instance of the bullet object? This seems like a very processor-intensive operation. Note: This is a small-scale project, so I'm OK with not implementing a huge texture-management framework since there won't be more than half a dozen or so in the entire game. I'd still like to hear about scalable solutions for future applications, though.

    Read the article

  • which platform to choose for designing a game

    - by Pramod
    I am new to gaming platform and don't have any experience in gaming as well. I want to develop a small shooting game and don't have any idea from where to start and which platform to use like things. I have some experience in java and .net. Can anyone help me in giving me a start? I don't mind even if this question is voted down or closed. But please do help me. I've tried searching other similar questions but everyone is already into gaming and i can't get any of the words. Please refer me to some books or tutorials

    Read the article

  • Mobile 3D engine renders alpha as full-object transparency

    - by Nils Munch
    I am running a iOS project using the isgl3d framework for showing pod files. I have a stylish car with 0.5 alpha windows, that I wish to render on a camera background, seeking some augmented reality goodness. The alpha on the windows looks okay, but when I add the object, I notice that it renders the entire object transparently, where the windows are. Including interior of the car. Like so (in example, keyboard can be seen through the dashboard, seats and so on. should be solid) The car interior is a seperate object with alpha 1.0. I would rather not show a "ghost car" in my project, but I haven't found a way around this. Have anyone encountered the same issue, and eventually reached a solution ?

    Read the article

  • Implement 2x speed in tower of defense type game

    - by Siddharth
    I was currently developing tower of defense game and I want to implement 2x feature for my game. Game usually run with 1x speed that was normal speed of the game. Here what 1x and 2x mean : 1x - mention normal speed of the game, 2x - mention the game object moves with double speed means user experience the fast game play. I want to implement such functionality for my game. The functionality that I want contains in the game Medieval Castle game that was available in the market. https://play.google.com/store/apps/details?id=com.nova.root&feature=search_result#?t=W251bGwsMSwxLDEsImNvbS5ub3ZhLnJvb3QiXQ.. The screen shot also shows the 1x and 2x button in that game. I think for 2x speed of the game I have to increase the speed of each object that were in the game. So any member please help what to do for that implementation. Only idea become enough for me.

    Read the article

  • Corona SDK: Quality of support and resources?

    - by Nick Wiggill
    I've not used Corona SDK before and am looking into it for a friend. (He is also considering Unity.) I wonder what the support is like for Corona? While Unity has a great many customers and so the Unity team can often not address issues directly, the community at large is very helpful and there are many excellent resources: tutorials, forum posts, code resources. What is Corona like in this regard, and by comparison?

    Read the article

  • How can I locate empty space next to polygon regions?

    - by Stephen
    Let's say I have the following area in a top-down map: The circle is the player, the black square is an obstacle, and the grey polygons with red borders are walk-able areas that will be used as a navigation mesh for enemies. Obstacles and grey polygons are always convex. The grey regions were defined using an algorithm when the world was generated at runtime. Notice the little white column. I need to figure out where any empty space like this is, if at all, after the algorithm builds the grey regions, so that I can fill the space with another region. Basically what I'm hoping for is an algorithm that can detect empty space next to a polygon.

    Read the article

  • Open source level editor for HTML5 platform game?

    - by Lai Yu-Hsuan
    A natty GUI editor is very helpful to create level map. I want to use some open-source choices rather than build my own from scratch. I found Tiled Map Editor but it doesn't work for what I want. Though I'm building HTML5 game, I don't have to use a HTML5 level editor as long as it can output well-formatted map files which my javascript can read. Edit: Sorry for the confusion. Tiled does not work for me because to make the player perform a 'tricky' jump, sometimes I want to set the distance between two platforms to, say, 7/3 or 8/3 tiles. But in Tiled I get only 2 or 3. If Tiled can do this, please teach me.

    Read the article

  • converting a mouse click to a ray

    - by Will
    I have a perspective projection. When the user clicks on the screen, I want to compute the ray between the near and far planes that projects from the mouse point, so I can do some ray intersection code with my world. I am using my own matrix and vector and ray classes and they all work as expected. However, when I try and convert the ray to world coordinates my far always ends up as 0,0,0 and so my ray goes from the mouse click to the centre of the object space, rather than through it. (The x and y coordinates of near and far are identical, they differ only in the z coordinates where they are negatives of each other) GLint vp[4]; glGetIntegerv(GL_VIEWPORT,vp); matrix_t mv, p; glGetFloatv(GL_MODELVIEW_MATRIX,mv.f); glGetFloatv(GL_PROJECTION_MATRIX,p.f); const matrix_t inv = (mv*p).inverse(); const float unit_x = (2.0f*((float)(x-vp[0])/(vp[2]-vp[0])))-1.0f, unit_y = 1.0f-(2.0f*((float)(y-vp[1])/(vp[3]-vp[1]))); const vec_t near(vec_t(unit_x,unit_y,-1)*inv); const vec_t far(vec_t(unit_x,unit_y,1)*inv); ray = ray_t(near,far-near); What have I got wrong? (How do you unproject the mouse-point?)

    Read the article

  • How to attach turrets to tiles in a tile based game

    - by Joseph St. Pierre
    I am a flash developer, and I am building a Tower Defense game. The world is being built through tiles, and I have gotten that accomplished easily. I have also gotten level changes and enemy spawning down as well. However, I wish the player to be able to spawn turrets, and have those turrets be on specific tiles, based upon where the player placed it. Here is my code: stop(); colOffset = 50; rowOffset = 50; guns = []; placed = true; dead = 0; spawned = 0; level = 1; interval = 350 / level; amount = level * 20; counter = 0; numCol = 14; numRow = 10; tiles = []; k = 0; create = false; tileName = new Array("road","grass","end", "start"); board = new Array( new Array(1,1,1,1,3,1,1,1,1,1,2,1,1,1), new Array(1,1,1,0,0,1,1,1,1,1,0,1,1,1), new Array(1,1,1,0,1,1,1,1,1,1,0,0,1,1), new Array(1,1,1,0,0,0,1,1,1,1,1,0,1,1), new Array(1,1,1,0,1,0,0,0,1,1,1,0,0,1), new Array(1,1,1,0,1,1,1,0,0,1,1,1,0,1), new Array(1,1,0,0,1,1,1,1,0,1,1,0,0,1), new Array(1,1,0,1,1,1,1,1,0,1,0,0,1,1), new Array(1,1,0,0,0,0,0,0,0,1,0,1,1,1), new Array(1,1,1,1,1,1,1,1,0,0,0,1,1,1) ); buildBoard(); function buildBoard(){ for ( col = 0; col < numCol; col++){ for ( row = 0; row < numRow; row++){ _root.attachMovie("tile", "tile_" + col + "_" + row, _root.getNextHighestDepth()); theTile = eval("tile_" + col + "_" + row); theTile._x = (col * 50); theTile._y = (row * 50); theTile.row = row; theTile.col = col; tileType = board[row][col]; theTile.gotoAndStop(tileName[tileType]); tiles.push(theTile); } } } init(); function init(){ onEnterFrame = function(){ counter += 1; if ( spawned < amount && counter > 50){ min= _root.attachMovie("minion","minion",_root.getNextHighestDepth()); min._x = tile_4_0._x + 25; min._y = tile_4_0._y + 25; min.health = 100; choose = Math.round(Math.random()); if ( choose == 0 ){ min.waypointX = [ tile_4_1._x +25, tile_3_1._x + 25, tile_3_2._x + 25, tile_3_6._x + 25, tile_2_6._x + 25, tile_2_8._x + 25, tile_8_8._x + 25, tile_8_9._x + 25, tile_10_9._x + 25, tile_10_7._x + 25, tile_11_7._x + 25, tile_11_6._x + 25, tile_12_6._x + 25, tile_12_4._x + 25, tile_11_4._x + 25, tile_11_2._x + 25, tile_10_2._x + 25, tile_10_0._x + 25]; min.waypointY = [ tile_4_1._y +25, tile_3_1._y + 25, tile_3_2._y + 25, tile_3_6._y + 25, tile_2_6._y + 25, tile_2_8._y + 25, tile_8_8._y + 25, tile_8_9._y + 25, tile_10_9._y + 25, tile_10_7._y + 25, tile_11_7._y + 25, tile_11_6._y + 25, tile_12_6._y + 25, tile_12_4._y + 25, tile_11_4._y + 25, tile_11_2._y + 25, tile_10_2._y + 25, tile_10_0._y + 25]; } else if ( choose == 1 ){ min.waypointX = [ tile_4_1._x +25, tile_3_1._x + 25, tile_3_2._x + 25, tile_3_3._x + 25, tile_5_3._x + 25, tile_5_4._x + 25, tile_7_4._x + 25, tile_7_5._x + 25, tile_8_5._x + 25, tile_8_8._x + 25, tile_8_9._x + 25, tile_10_9._x + 25, tile_10_7._x + 25, tile_11_7._x + 25, tile_11_6._x + 25, tile_12_6._x + 25, tile_12_4._x + 25, tile_11_4._x + 25, tile_11_2._x + 25, tile_10_2._x + 25, tile_10_0._x + 25 ]; min.waypointY = [ tile_4_1._y +25, tile_3_1._y + 25, tile_3_2._y + 25, tile_3_3._y + 25, tile_5_3._y + 25, tile_5_4._y + 25, tile_7_4._y + 25, tile_7_5._y + 25, tile_8_5._y + 25, tile_8_8._y + 25, tile_8_9._y + 25, tile_10_9._y + 25, tile_10_7._y + 25, tile_11_7._y + 25, tile_11_6._y + 25, tile_12_6._y + 25, tile_12_4._y + 25, tile_11_4._y + 25, tile_11_2._y + 25, tile_10_2._y + 25, tile_10_0._y + 25 ]; } min.i = 0; counter = 0; spawned += 1; min.onEnterFrame = function(){ dx = this.waypointX[this.i] - this._x; dy = this.waypointY[this.i] - this._y; radians = Math.atan2(dy,dx); degrees = radians * 180 / Math.PI; xspeed = Math.cos(radians); yspeed = Math.sin(radians); this._x += xspeed; this._y += yspeed; if( this._x == this.waypointX[this.i] && this._y == this.waypointY[this.i]){ this.i++; } if ( this._x == tile_10_0._x + 25 && this._y == tile_10_0._y + 25){ this.removeMovieClip(); dead += 1; } } } if ( dead >= amount ){ dead = 0; level += 1; amount = level * 20; spawned = 0; } } btnM.onRelease = function(){ create = true; } } game.onEnterFrame = function(){ } It is possible for me however to complete this task, but only once. I am able to make the turret, drag it over to a tile, and have it attach itself to the tile. No problem. The issue is, I cannot do these multiple times. Please Help.

    Read the article

  • OpenGL-ES: clearing the alpha of the FrameBufferObject

    - by MrDatabase
    This question is a follow-up to Texture artifacts on iPad How does one "clear the alpha of the render texture frameBufferObject"? I've searched around here, StackOverflow and various search engines but no luck. I've tried a few things... for example calling GlClear(GL_COLOR_BUFFER_BIT) at the beginning of my render loop... but it doesn't seem to make a difference. Any help is appreciated since I'm still new to OpenGL. Cheers! p.s. I read on SO and in Apple's documentation that GlClear should always be called at the beginning of the renderLoop. Agree? Disagree? Here's where I read this: http://stackoverflow.com/questions/2538662/how-does-glclear-improve-performance

    Read the article

  • Unity3D - Projection matrix camera frustum

    - by MulletDevil
    I've used off centre projection to create a custom projection matrix for my camera. When I run the game I can see the scene correctly in the game view but in the editor view the camera frustum is not correct. It still shows the original frustum shape not the new one. It also appears that Unity is using the original frustum for frustum culling and not the new one as I can see object being culled which are visible to the new frustum but would not be visible in the old one. Am I wrong in thinking that a custom projection matrix would alter the view frustum? Or am I missing something else?

    Read the article

  • What are the benefits of designing a KeyBinding relay?

    - by Adam Naylor
    The input system of Quake3 is handled using a Keybinding relay, whereby each keypress is matched against a 'binding' which is then passed to the CLI along with a time stamp of when the keypress (or release) occurred. I just wanted to get an idea from developers what they considered to be the key benefits of designing your input system around this approach? One thing i don't particularly like is the appending of the timestamp to the bound command. This seems like a bit of a hack to bend the CLI into handling the games input? Also I feel that detecting the keypress only to add the command to a stream of text that gets parsed at a later date to be a slightly latent way of responding to input? (or is this unfounded?) The only real benefit i can see is that it allows you to bind 'complex' commands to keypresses; like 'switch weapon;+fire;' for example. Or maybe for journaling purposes? Thanks for any insights!

    Read the article

  • Making entire scene fade to grayscale

    - by Fibericon
    When the player loses all of their lives, I want the entire game screen to go grayscale, but not stop updating immediately. I'd also prefer it fade to grayscale instead of suddenly lose all color. Everything I've found so far is either about taking a screenshot and making it grayscale, or making a specific texture grayscale. Is there a way to change the entire playing field and all objects within to grayscale without iterating through everything?

    Read the article

  • How should I unbind and delete OpenAL buffers?

    - by Joe Wreschnig
    I'm using OpenAL to play sounds. I'm trying to implement a fire-and-forget play function that takes a buffer ID and assigns it to a source from a pool I have previously allocated, and plays it. However, there is a problem with object lifetimes. In OpenGL, delete functions either automatically unbind things (e.g. textures), or automatically deletes the thing when it eventually is unbound (e.g. shaders) and so it's usually easy to manage deletion. However alDeleteBuffers instead simply fails with AL_INVALID_OPERATION if the buffer is still bound to a source. Is there an idiomatic way to "delete" OpenAL buffers that allows them to finish playing, and then automatically unbinds and really them? Do I need to tie buffer management more deeply into the source pool (e.g. deleting a buffer requires checking all the allocated sources also)? Similarly, is there an idiomatic way to unbind (but not delete) buffers when they are finished playing? It would be nice if, when I was looking for a free source, I only needed to see if a buffer was attached at all and not bother checking the source state. (I'm using C++, although approaches for C are also fine. Approaches assuming a GCd language and using finalizers are probably not applicable.)

    Read the article

  • Constant game speed independent of variable FPS in OpenGL with GLUT?

    - by Nazgulled
    I've been reading Koen Witters detailed article about different game loop solutions but I'm having some problems implementing the last one with GLUT, which is the recommended one. After reading a couple of articles, tutorials and code from other people on how to achieve a constant game speed, I think that what I currently have implemented (I'll post the code below) is what Koen Witters called Game Speed dependent on Variable FPS, the second on his article. First, through my searching experience, there's a couple of people that probably have the knowledge to help out on this but don't know what GLUT is and I'm going to try and explain (feel free to correct me) the relevant functions for my problem of this OpenGL toolkit. Skip this section if you know what GLUT is and how to play with it. GLUT Toolkit: GLUT is an OpenGL toolkit and helps with common tasks in OpenGL. The glutDisplayFunc(renderScene) takes a pointer to a renderScene() function callback, which will be responsible for rendering everything. The renderScene() function will only be called once after the callback registration. The glutTimerFunc(TIMER_MILLISECONDS, processAnimationTimer, 0) takes the number of milliseconds to pass before calling the callback processAnimationTimer(). The last argument is just a value to pass to the timer callback. The processAnimationTimer() will not be called each TIMER_MILLISECONDS but just once. The glutPostRedisplay() function requests GLUT to render a new frame so we need call this every time we change something in the scene. The glutIdleFunc(renderScene) could be used to register a callback to renderScene() (this does not make glutDisplayFunc() irrelevant) but this function should be avoided because the idle callback is continuously called when events are not being received, increasing the CPU load. The glutGet(GLUT_ELAPSED_TIME) function returns the number of milliseconds since glutInit was called (or first call to glutGet(GLUT_ELAPSED_TIME)). That's the timer we have with GLUT. I know there are better alternatives for high resolution timers, but let's keep with this one for now. I think this is enough information on how GLUT renders frames so people that didn't know about it could also pitch in this question to try and help if they fell like it. Current Implementation: Now, I'm not sure I have correctly implemented the second solution proposed by Koen, Game Speed dependent on Variable FPS. The relevant code for that goes like this: #define TICKS_PER_SECOND 30 #define MOVEMENT_SPEED 2.0f const int TIMER_MILLISECONDS = 1000 / TICKS_PER_SECOND; int previousTime; int currentTime; int elapsedTime; void renderScene(void) { (...) // Setup the camera position and looking point SceneCamera.LookAt(); // Do all drawing below... (...) } void processAnimationTimer(int value) { // setups the timer to be called again glutTimerFunc(TIMER_MILLISECONDS, processAnimationTimer, 0); // Get the time when the previous frame was rendered previousTime = currentTime; // Get the current time (in milliseconds) and calculate the elapsed time currentTime = glutGet(GLUT_ELAPSED_TIME); elapsedTime = currentTime - previousTime; /* Multiply the camera direction vector by constant speed then by the elapsed time (in seconds) and then move the camera */ SceneCamera.Move(cameraDirection * MOVEMENT_SPEED * (elapsedTime / 1000.0f)); // Requests to render a new frame (this will call my renderScene() once) glutPostRedisplay(); } void main(int argc, char **argv) { glutInit(&argc, argv); (...) glutDisplayFunc(renderScene); (...) // Setup the timer to be called one first time glutTimerFunc(TIMER_MILLISECONDS, processAnimationTimer, 0); // Read the current time since glutInit was called currentTime = glutGet(GLUT_ELAPSED_TIME); glutMainLoop(); } This implementation doesn't fell right. It works in the sense that helps the game speed to be constant dependent on the FPS. So that moving from point A to point B takes the same time no matter the high/low framerate. However, I believe I'm limiting the game framerate with this approach. Each frame will only be rendered when the time callback is called, that means the framerate will be roughly around TICKS_PER_SECOND frames per second. This doesn't feel right, you shouldn't limit your powerful hardware, it's wrong. It's my understanding though, that I still need to calculate the elapsedTime. Just because I'm telling GLUT to call the timer callback every TIMER_MILLISECONDS, it doesn't mean it will always do that on time. I'm not sure how can I fix this and to be completely honest, I have no idea what is the game loop in GLUT, you know, the while( game_is_running ) loop in Koen's article. But it's my understanding that GLUT is event-driven and that game loop starts when I call glutMainLoop() (which never returns), yes? I thought I could register an idle callback with glutIdleFunc() and use that as replacement of glutTimerFunc(), only rendering when necessary (instead of all the time as usual) but when I tested this with an empty callback (like void gameLoop() {}) and it was basically doing nothing, only a black screen, the CPU spiked to 25% and remained there until I killed the game and it went back to normal. So I don't think that's the path to follow. Using glutTimerFunc() is definitely not a good approach to perform all movements/animations based on that, as I'm limiting my game to a constant FPS, not cool. Or maybe I'm using it wrong and my implementation is not right? How exactly can I have a constant game speed with variable FPS? More exactly, how do I correctly implement Koen's Constant Game Speed with Maximum FPS solution (the fourth one on his article) with GLUT? Maybe this is not possible at all with GLUT? If not, what are my alternatives? What is the best approach to this problem (constant game speed) with GLUT? I originally posted this question on Stack Overflow before being pointed out about this site. The following is a different approach I tried after creating the question in SO, so I'm posting it here too. Another Approach: I've been experimenting and here's what I was able to achieve now. Instead of calculating the elapsed time on a timed function (which limits my game's framerate) I'm now doing it in renderScene(). Whenever changes to the scene happen I call glutPostRedisplay() (ie: camera moving, some object animation, etc...) which will make a call to renderScene(). I can use the elapsed time in this function to move my camera for instance. My code has now turned into this: int previousTime; int currentTime; int elapsedTime; void renderScene(void) { (...) // Setup the camera position and looking point SceneCamera.LookAt(); // Do all drawing below... (...) } void renderScene(void) { (...) // Get the time when the previous frame was rendered previousTime = currentTime; // Get the current time (in milliseconds) and calculate the elapsed time currentTime = glutGet(GLUT_ELAPSED_TIME); elapsedTime = currentTime - previousTime; /* Multiply the camera direction vector by constant speed then by the elapsed time (in seconds) and then move the camera */ SceneCamera.Move(cameraDirection * MOVEMENT_SPEED * (elapsedTime / 1000.0f)); // Setup the camera position and looking point SceneCamera.LookAt(); // All drawing code goes inside this function drawCompleteScene(); glutSwapBuffers(); /* Redraw the frame ONLY if the user is moving the camera (similar code will be needed to redraw the frame for other events) */ if(!IsTupleEmpty(cameraDirection)) { glutPostRedisplay(); } } void main(int argc, char **argv) { glutInit(&argc, argv); (...) glutDisplayFunc(renderScene); (...) currentTime = glutGet(GLUT_ELAPSED_TIME); glutMainLoop(); } Conclusion, it's working, or so it seems. If I don't move the camera, the CPU usage is low, nothing is being rendered (for testing purposes I only have a grid extending for 4000.0f, while zFar is set to 1000.0f). When I start moving the camera the scene starts redrawing itself. If I keep pressing the move keys, the CPU usage will increase; this is normal behavior. It drops back when I stop moving. Unless I'm missing something, it seems like a good approach for now. I did find this interesting article on iDevGames and this implementation is probably affected by the problem described on that article. What's your thoughts on that? Please note that I'm just doing this for fun, I have no intentions of creating some game to distribute or something like that, not in the near future at least. If I did, I would probably go with something else besides GLUT. But since I'm using GLUT, and other than the problem described on iDevGames, do you think this latest implementation is sufficient for GLUT? The only real issue I can think of right now is that I'll need to keep calling glutPostRedisplay() every time the scene changes something and keep calling it until there's nothing new to redraw. A little complexity added to the code for a better cause, I think. What do you think?

    Read the article

< Previous Page | 383 384 385 386 387 388 389 390 391 392 393 394  | Next Page >