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genesys

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About genesys

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  1.   Thank you for  your help, Hodgman! I tried this, but get a GL_INVALID_OPERATION error
  2. The OpenGL wiki about GLsync objects (https://www.opengl.org/wiki/Sync_Object) states:   "Sync objects are never bound to the context, nor do they encapsulate state the way normal GL objects do. These are not OpenGL objects."   On Android it's possible to create a native sync from a EGLsync through the ANDROID_native_fence_sync extension which allows to check the state of the fence through a file descriptor (aparently under the hood the EGLsync on Android is implemented as a file descriptor).   These things make me believe that it should be perfectly possible to check the signaled state of a GLsync object without having to perform an API call. The reason I am looking for such a way is because I want to check the signaled state of a GLsync on a worker thread and creating a second context for the worker thread solely to check the state of the sync feels overkill (plus, even though multiple contexts work fine with each other in theory, in the real world they seem to often cause obscure problems).   I am on windows, does anyone know a way to check the state of a GLsync without calling into the API?
  3. Hello I'm doing some research work that relies on 3D engines which make use of deferred lighting. In order to create good looking and relevant examples, I'm looking for opensource engines (and preferrably games) that make use of deferred lighting into which i can integrate my rendering methods. Now, I was investigating id Tech 4 as I know that it uses deferred lighting and because it became opensource. But now i read that the initial open Source release is based on an older version which does not incorporate deferred lighting. Does anyone know of an opensource version of id Tech 4 with this feature added, or can suggest another opensource engine including impressivley looking opensource game that makes use of deferred lighting? Thanks!
  4. genesys

    RaceTrack AI?

    Hello! does anyone know a resource describing an AI algorithm to solve the 'RaceTrack' http://en.wikipedia.org/wiki/Racetrack_%28game%29 game? thanks!
  5. I googled a bit but couldn't find something yet. does anyone know some webstore where one can buy quality royaltyfree sprites and pixelart?
  6. stencil is unfortunately not available on the device. maybe it will be enough for my needs to use the vertexcolors for the transparency mask. I'll test that now. Is there a possibility to alter the vertex alpha by a texture alpha with a different different texture environment (GL_MODULATE, GL_ADD etc) than the vertex color is modulated by the texture color? thanks.
  7. obviously there are several solutions. for example i could render the geometry with 3 passes: pass1: -texture1 pass2 -alphaTexture -texture2 pass3 (additive blending) -reflection texture but i'd prefere doing it somehow in a single pass. is there a way i can combine two textures acording to a bitmask into one single texture? maybe on the CPU and then reupload to the GPU
  8. I have two textures (1024x1024, fully MipMapped, both PVRTC-4bitsPerPixel compressed). The Textures are applied on a 3D mesh. On the CPU I'm updating a 512x512 boolean array which is updated only every few seconds. Now I want to blend texture 2 over texture 1 with respect to this boolean array (true means the respective 4 pixels of texture1 are visible, false means the other texture is visible at this location) My hardware has two texture units available of which i'm using the second texture unit for a reflection texture. How can I do that? Thanks!
  9. Hi! I know there are plenty of patents filed to protect certain game mechanics. Stuff like a "sanity meter" (displaying how sane your character is) or minigames during level loading are protected. How can you efficiently search for such game related patents (before you start working on your game) in order to avoid running into trouble? thanks!
  10. figured it out! :) glTexEnvf( GL_TEXTURE_FILTER_CONTROL_EXT, GL_TEXTURE_LOD_BIAS_EXT, value ); let's you set a bias to the chosen miplevel. the bias is applied for the currently active texture unit. A value of -0.7f worked well for me. crisp textures and only little aliasing.
  11. Hi! Mipmapping is a good thing, it gets rid of some aliasing. However, it also blurs out details pretty much. Especially if anisotropic mimapping is turned off (due to device limitations or performance reasons). I'd like to know whether there's any way to manually chose the mipmap level to be used - or for example to make the graphicshardware always chose the next larger version instead of the one it would usually chose (creating a bit of aliasing, but not too much, and getting rid of blurring). Any tips on that? thanks!
  12. hey and thanks for your replies. I know acceleration strctures such as oct and KD trees. however, i think they'll not apropriate here, since my bullets move (the octtree would have to be altered in each frame also - i'm not testing rays, but spheres against intersections with the points stored in the structure testing each bullet against each objects boundingsphere has bad computational complexity
  13. What's the computationally best aproach to have a lot of bullets (volumeless 3d points with position and velocity) collide with 3D objects? At the moment, in each timestep, i subscribe all bullets into a 3D grid Then, for each gameobject { i take it's boundingsphere and calculate which gridcells intersect with this boundingsphere. Then, for each of those gridcells { I test for each bullet in the gridcell {if it is within the boundingsphere. if the bullet is within the boundingsphere, i test against the actual geometry. } } } Is there a better aproach (i'm on a mobile device, so performance is crucial), especially for the broad-phase? Thanks!
  14. genesys

    cheap LOD level selection function

    @darragh: i already do something like this. i have the boundingsphere and i create two points at either side of the object (seen from the camera direction) and transform those two points into screenspace and measure distance. But this requires one matrixmatrix multiplication (for getting the modelviewprojection) and two matrix-vector multiplication as well as one squareroot. i was looking for something cheaper since i have hundrets of objects. it's not directly my bottleneck, but it's part of it so i try to optimize it.
  15. genesys

    cheap LOD level selection function

    Hey and thanks for your answer maybe i was not clear enough about this. It doesn't matter whether it's centered, on the edge of the screen or off screen or whatever. a LOD level should be chosen by the size the object appears on screen. But the size doesn't depend only on distance to the camera, but also on the current camera angle (for example one could zoom onto an object by decreasing the camera angle - then a higher resolution LOD level should be accessed, because the object appears larger on screen). i'm searching for a cheap function that returns a value somewhat linear to the diameter (or maybe area) the object will take on screen.
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