Search Results

Search found 15 results on 1 pages for 'jenko'.

Page 1/1 | 1 

• Ray-plane intersection to find the Z of the intersecting point

  - by Jenko

  I have a rectangle in 3d space (p1, p2, p3, p4) and when the mouse rolls over it I need to calculate the exact Z of the point on the rect, given the mouse coordinates (x, y). Would a Ray-plane intersection find the Z of the intersecting point? Edit: Would this one-liner work? .. it returns the t value for the intersection, apparently the Z value. float rayPlane(vector3D planepoint, vector3D normal, vector3D origin, vector3D direction){ return -((origin-planepoint).dot(normal))/(direction.dot(normal)); }

  Read the article

• Drawing a textured triangle with CPU instead of GPU

  - by Jenko

  I understand the benefits of GPU rendering and such, but for a certain limited application I need to render textured triangles purely using CPU. I've built a 3D engine capable of object handling, transform, projection, culling and the likes ... now all I need is a little code snippet that draws a single textured triangle onto a bitmap... any language accepted! Inputs: Texture bitmap, Triangle U/V/W coords, Triangle X/Y screen coords Output: The textured triangle drawn at the given screen coords I've currently been using a platform function to draw triangles to screen, but I'm looking to handle it myself to speeden up the process.

  Read the article

• Any reliable polygon normal calculation code?

  - by Jenko

  Do you have any reliable face normal calculation code? I'm using this but it fails when faces are 90 degrees upright or similar. // the normal point var x:Number = 0; var y:Number = 0; var z:Number = 0; // if is a triangle with 3 points if (points.length == 3) { // read vertices of triangle var Ax:Number, Bx:Number, Cx:Number; var Ay:Number, By:Number, Cy:Number; var Az:Number, Bz:Number, Cz:Number; Ax = points[0].x; Bx = points[1].x; Cx = points[2].x; Ay = points[0].y; By = points[1].y; Cy = points[2].y; Az = points[0].z; Bz = points[1].z; Cz = points[2].z; // calculate normal of a triangle x = (By - Ay) * (Cz - Az) - (Bz - Az) * (Cy - Ay); y = (Bz - Az) * (Cx - Ax) - (Bx - Ax) * (Cz - Az); z = (Bx - Ax) * (Cy - Ay) - (By - Ay) * (Cx - Ax); // if is a polygon with 4+ points }else if (points.length > 3){ // calculate normal of a polygon using all points var n:int = points.length; x = 0; y = 0; z = 0 // ensure all points above 0 var minx:Number = 0, miny:Number = 0, minz:Number = 0; for (var p:int = 0, pl:int = points.length; p < pl; p++) { var po:_Point3D = points[p] = points[p].clone(); if (po.x < minx) { minx = po.x; } if (po.y < miny) { miny = po.y; } if (po.z < minz) { minz = po.z; } } if (minx > 0 || miny > 0 || minz > 0){ for (p = 0; p < pl; p++) { po = points[p]; po.x -= minx; po.y -= miny; po.z -= minz; } } var cur:int = 1, prev:int = 0, next:int = 2; for (var i:int = 1; i <= n; i++) { // using Newell method x += points[cur].y * (points[next].z - points[prev].z); y += points[cur].z * (points[next].x - points[prev].x); z += points[cur].x * (points[next].y - points[prev].y); cur = (cur+1) % n; next = (next+1) % n; prev = (prev+1) % n; } } // length of the normal var length:Number = Math.sqrt(x * x + y * y + z * z); // if area is 0 if (length == 0) { return null; }else{ // turn large values into a unit vector x = x / length; y = y / length; z = z / length; }

  Read the article

• How do you calculate UVW coordinates?

  - by Jenko

  I'm working on a 3d engine and I'm calculating UVT coordinates, where U and V represent pixels on the texture measured in 0-1, and T is: T = perspective / Z But I'm trying to use this perspective-correct triangle rasteriser, which requires a W, per vertex. How do I calculate the W for each vertex for the drawPerspectiveTexturedPolygon() function? Hint: The code comments refer to W as the "homogenous coordinate" ... does that mean anything?

  Read the article

• Any reliable polygon normal calculation code?

  - by Jenko

  I'm currently calculating the normal vector of a polygon using this code, but for some faces here and there it calculates a wrong normal. I don't really know what's going on or where it fails but its not reliable. Do you have any polygon normal calculation that's tested and found to be reliable? // calculate normal of a polygon using all points var n:int = points.length; var x:Number = 0; var y:Number = 0; var z:Number = 0 // ensure all points above 0 var minx:Number = 0, miny:Number = 0, minz:Number = 0; for (var p:int = 0, pl:int = points.length; p < pl; p++) { var po:_Point3D = points[p] = points[p].clone(); if (po.x < minx) { minx = po.x; } if (po.y < miny) { miny = po.y; } if (po.z < minz) { minz = po.z; } } for (p = 0; p < pl; p++) { po = points[p]; po.x -= minx; po.y -= miny; po.z -= minz; } var cur:int = 1, prev:int = 0, next:int = 2; for (var i:int = 1; i <= n; i++) { // using Newell method x += points[cur].y * (points[next].z - points[prev].z); y += points[cur].z * (points[next].x - points[prev].x); z += points[cur].x * (points[next].y - points[prev].y); cur = (cur+1) % n; next = (next+1) % n; prev = (prev+1) % n; } // length of the normal var length:Number = Math.sqrt(x * x + y * y + z * z); // turn large values into a unit vector if (length != 0){ x = x / length; y = y / length; z = z / length; }else { throw new Error("Cannot calculate normal since triangle has an area of 0"); }

  Read the article

• Strange 3D game engine camera with X,Y,Zoom instead of X,Y,Z

  - by Jenko

  I'm using a 3D game engine, that uses a 4x4 matrix to modify the camera projection, in this format: r r r x r r r y r r r z - - - zoom Strangely though, the camera does not respond to the Z translation parameter, and so you're forced to use X, Y, Zoom to move the camera around. Technically this is plausible for isometric-style games such as Age Of Empires III. But this is a 3D engine, and so why would they have designed the camera to ignore Z and respond only to zoom? Am I missing something here? I've tried every method of setting the camera and it really seems to ignore Z. So currently I have to resort to moving the main object in the scene graph instead of moving the camera in relation to the objects. My question: Do you have any idea why the engine would use such a scheme? Is it common? Why? Or does it seem like I'm missing something and the SetProjection(Matrix) function is broken and somehow ignores the Z translation in the matrix? (unlikely, but possible) Anyhow, what are the workarounds? Is moving objects around the only way? Edit: I'm sorry I cannot reveal much about the engine because we're in a binding contract. It's a locally developed engine (Australia) written in managed C# used for data visualizations. Edit: The default mode of the engine is orthographic, although I've switched it into perspective mode. Its probably more effective to use X, Y, Zoom in orthographic mode, but I need to use perspective mode to render everyday objects as well.

  Read the article

• How to connect to a serverside process on Ubuntu running in a VM?

  - by Jenko

  I am running Ubuntu 11.10 in VirtualBox, on Windows 7. I'm trying to setup a serverside process like Apache on it. How do I configure VirtualBox to allow access to the Ubuntu server process from other computers on the network? I can access the internet from Ubuntu. The Windows 7 computer is on a WiFi network using DHCP. The WiFi network has a dynamic IP with the network provider. This is my current configuration:

  Read the article

• How does a BSP tree work for Z sorting?

  - by Jenko

  I'm developing a 3D engine in software, and so I must compute Z sorting manually. I'm currently using the painters algorithm to sort triangles and then drawing them back-to-front. This causes artifacts that I'm trying to correct. Would using a dynamic BSP-tree ensure "correct Z sorting" of triangles? Why? Because the bounding volumes of triangles would be similar? Since I would have a single "world" BSP tree, would I have to remove and re-add any moved/scaled/rotated object into the tree? Is it possible to add triangles into a BSP tree without the expensive cutting process? Why do you need to cut triangles on the axis planes anyway? Is it faster to traverse a BSP tree from any angle, than to sort all tris each draw like the painters algorithm?

  Read the article

• Startup a Ubuntu FTP and SSH server without logging in

  - by Jenko

  I have a Ubuntu Server 11.10 box, which I would like to run "headless", and without a keyboard, mouse or display. Is it possible that immediately after startup the machine logs into an account, or allows me to control the machine from my Windows 7 machine nearby via SSH and SFTP? I've got OpenSSH server installed, and even when the box is not logged in I can start an SSH session. I've tried installing VSFTPD but its very troublesome (hardly connects) and only starts when I login locally into the box.

  Read the article

• How do you describe your profession in a public place or conference?

  - by Jenko

  I've often been in situations where non-technical people ask me, "So, what do you do?" ... and I've found it somewhat hard to describe that I spend the entirely of my days pouring over colored text. Of course, its quite reasonable to say "I design software" or "I develop computer applications", but that still feels somewhat "lame" and generic. So how do you describe your profession in public situations? are there any insights for those of us less gifted in public speaking?

  Read the article

• 3D game engines for XNA games

  - by Jenko

  Before I start development of an XNA game, I need to choose a 3D game engine to develop upon. Is this belief unfounded? Does XNA have basic object transformation, lighting and mesh/texture importing functionality by which you can develop a decent 3D side-scrolling game? Chances are I'm going to need a 3D engine such as Torque X to handle most of the special effects, animation and sound for me. What are the engines that you recommend building an XNA game with? What work reliably in your experience? Is XNA alone enough? do you have repositories of code that work directly with XNA to create effects and other game environments with sunlight, fog and rain?

  Read the article

• Show which modifier keys are pressed during screen recording?

  - by Jenko

  I'd like to see which modifier keys I've pressed during screen recordings so my students can understand what keys I've pressed while I click and drag. Is there any software that can do this? I'm aware that Windows 7 does this internally, if there's a way to enable it. Windows 7 When you have a Wacom tablet connected to your PC, or if you have a Tablet PC, windows shows little yellow tip bubbles whenever you press modifier keys. Any way to enable these on a normal PC? Update: I've tried starting the Tablet PC Input Service but nothing happens. The Tablet PC Settings dialog has nothing interesting either. Is there a registry setting I can tweak?

  Read the article

• Is there a filesystem firewall?

  - by Jenko

  Ever since firewalls appeared on the scene, it became hard for rogue programs to access the internet. But you and I know that running applications get unrestricted access to the filesystem. They can read your files and send them to poppa. (programs such as web browsers and IM clients, which are allowed thru the internet firewall) Any way to know which programs are accessing your files? or limit their access to a specific partition?

  Read the article

• Prevent acccess to the C drive

  - by Jenko

  Is it possible to prevent regular users from accessing the C drive via Windows Explorer? they should be allowed to execute certain programs. This is to ensure that employees cannot steal or copy out proprietary software even though they should be able to execute it. One way would be to change the option in windows Group Policy and set the "shell" to something other than "explorer.exe". I'm looking for a similar windows setting that just hides the C drive or otherwise prevents trivial access. This is for Windows XP/7.

  Read the article

• Live javascript debugging by recording function calls and parameters

  - by Jenko

  Is there a debugging system that allows me to record javascript function calls and their parameters as they occur? this would allow me to trace and debug applications in live/client situations without the performance hit due to manual logging. Edit: I'm not talking about manually calling functions using a 'console' window and viewing the results, or manually adding 'trace' or 'log' commands into my javascript. I need it to work with any running javascript.

  Read the article

1