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  • BoundingBox created from mesh to origin, making it bigger

    - by Gunnar Södergren
    I'm working on a level-based survival game and I want to design my scenes in Maya and export them as a single model (with multiple meshes) into XNA. My problem is that when I try to create Bounding Boxes(for Collision purposes) for each of the meshes, the are calculated from origin to the far-end of the current mesh, so to speak. I'm thinking that it might have something to do with the position each mesh brings from Maya and that it's interpreted wrongly... or something. Here's the code for when I create the boxes: private static BoundingBox CreateBoundingBox(Model model, ModelMesh mesh) { Matrix[] boneTransforms = new Matrix[model.Bones.Count]; model.CopyAbsoluteBoneTransformsTo(boneTransforms); BoundingBox result = new BoundingBox(); foreach (ModelMeshPart meshPart in mesh.MeshParts) { BoundingBox? meshPartBoundingBox = GetBoundingBox(meshPart, boneTransforms[mesh.ParentBone.Index]); if (meshPartBoundingBox != null) result = BoundingBox.CreateMerged(result, meshPartBoundingBox.Value); } result = new BoundingBox(result.Min, result.Max); return result; } private static BoundingBox? GetBoundingBox(ModelMeshPart meshPart, Matrix transform) { if (meshPart.VertexBuffer == null) return null; Vector3[] positions = VertexElementExtractor.GetVertexElement(meshPart, VertexElementUsage.Position); if (positions == null) return null; Vector3[] transformedPositions = new Vector3[positions.Length]; Vector3.Transform(positions, ref transform, transformedPositions); for (int i = 0; i < transformedPositions.Length; i++) { Console.WriteLine(" " + transformedPositions[i]); } return BoundingBox.CreateFromPoints(transformedPositions); } public static class VertexElementExtractor { public static Vector3[] GetVertexElement(ModelMeshPart meshPart, VertexElementUsage usage) { VertexDeclaration vd = meshPart.VertexBuffer.VertexDeclaration; VertexElement[] elements = vd.GetVertexElements(); Func<VertexElement, bool> elementPredicate = ve => ve.VertexElementUsage == usage && ve.VertexElementFormat == VertexElementFormat.Vector3; if (!elements.Any(elementPredicate)) return null; VertexElement element = elements.First(elementPredicate); Vector3[] vertexData = new Vector3[meshPart.NumVertices]; meshPart.VertexBuffer.GetData((meshPart.VertexOffset * vd.VertexStride) + element.Offset, vertexData, 0, vertexData.Length, vd.VertexStride); return vertexData; } } Here's a link to the picture of the mesh(The model holds six meshes, but I'm only rendering one and it's bounding box to make it clearer: http://www.gsodergren.se/portfolio/wp-content/uploads/2011/10/Screen-shot-2011-10-24-at-1.16.37-AM.png The mesh that I'm refering to is the Cubelike one. The cylinder is a completely different model and not part of any bounding box calculation. I've double- (and tripple-)-checked that this mesh corresponds to this bounding box. Any thoughts on what I'm doing wrong?

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  • Project Euler 18: (Iron)Python

    - by Ben Griswold
    In my attempt to learn (Iron)Python out in the open, here’s my solution for Project Euler Problem 18.  As always, any feedback is welcome. # Euler 18 # http://projecteuler.net/index.php?section=problems&id=18 # By starting at the top of the triangle below and moving # to adjacent numbers on the row below, the maximum total # from top to bottom is 23. # # 3 # 7 4 # 2 4 6 # 8 5 9 3 # # That is, 3 + 7 + 4 + 9 = 23. # Find the maximum total from top to bottom of the triangle below: # 75 # 95 64 # 17 47 82 # 18 35 87 10 # 20 04 82 47 65 # 19 01 23 75 03 34 # 88 02 77 73 07 63 67 # 99 65 04 28 06 16 70 92 # 41 41 26 56 83 40 80 70 33 # 41 48 72 33 47 32 37 16 94 29 # 53 71 44 65 25 43 91 52 97 51 14 # 70 11 33 28 77 73 17 78 39 68 17 57 # 91 71 52 38 17 14 91 43 58 50 27 29 48 # 63 66 04 68 89 53 67 30 73 16 69 87 40 31 # 04 62 98 27 23 09 70 98 73 93 38 53 60 04 23 # NOTE: As there are only 16384 routes, it is possible to solve # this problem by trying every route. However, Problem 67, is the # same challenge with a triangle containing one-hundred rows; it # cannot be solved by brute force, and requires a clever method! ;o) import time start = time.time() triangle = [ [75], [95, 64], [17, 47, 82], [18, 35, 87, 10], [20, 04, 82, 47, 65], [19, 01, 23, 75, 03, 34], [88, 02, 77, 73, 07, 63, 67], [99, 65, 04, 28, 06, 16, 70, 92], [41, 41, 26, 56, 83, 40, 80, 70, 33], [41, 48, 72, 33, 47, 32, 37, 16, 94, 29], [53, 71, 44, 65, 25, 43, 91, 52, 97, 51, 14], [70, 11, 33, 28, 77, 73, 17, 78, 39, 68, 17, 57], [91, 71, 52, 38, 17, 14, 91, 43, 58, 50, 27, 29, 48], [63, 66, 04, 68, 89, 53, 67, 30, 73, 16, 69, 87, 40, 31], [04, 62, 98, 27, 23, 9, 70, 98, 73, 93, 38, 53, 60, 04, 23]] # Loop through each row of the triangle starting at the base. for a in range(len(triangle) - 1, -1, -1): for b in range(0, a): # Get the maximum value for adjacent cells in current row. # Update the cell which would be one step prior in the path # with the new total. For example, compare the first two # elements in row 15. Add the max of 04 and 62 to the first # position of row 14.This provides the max total from row 14 # to 15 starting at the first position. Continue to work up # the triangle until the maximum total emerges at the # triangle's apex. triangle [a-1][b] += max(triangle [a][b], triangle [a][b+1]) print triangle [0][0] print "Elapsed Time:", (time.time() - start) * 1000, "millisecs" a=raw_input('Press return to continue')

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  • Difference between Windows and Linux development environments?

    - by Ryan
    I have an interview coming up soon for a Business Analyst position and the recruiter mentioned some feedback from a prior candidate that was interviewed who said the interviewers asked him what the difference between a Windows and Linux development environment was. Are there some high level things I need to be aware of from a business point of view when working with a development team or designing an application on Windows vs Linux?

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  • Interleaving Arrays in OpenGL

    - by Benjamin Danger Johnson
    In my pursuit to write code that matches todays OpenGL standards I have found that I am completely clueless about interleaving arrays. I've tried and debugged just about everywhere I can think of but I can't get my model to render using interleaved arrays (It worked when it was configuered to use multiple arrays) Now I know that all the data is properly being parsed from an obj file and information is being copied properly copied into the Vertex object array, but I still can't seem to get anything to render. Below is the code for initializing a model and drawing it (along with the Vertex struct for reference.) Vertex: struct Vertex { glm::vec3 position; glm::vec3 normal; glm::vec2 uv; glm::vec3 tangent; glm::vec3 bitangent; }; Model Constructor: Model::Model(const char* filename) { bool result = loadObj(filename, vertices, indices); glGenVertexArrays(1, &vertexArrayID); glBindVertexArray(vertexArrayID); glGenBuffers(1, &vertexbuffer); glBindBuffer(GL_ARRAY_BUFFER, vertexbuffer); glBufferData(GL_ARRAY_BUFFER, vertices.size() * sizeof(Vertex), &vertices[0], GL_STATIC_DRAW); glGenBuffers(1, &elementbuffer); glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, elementbuffer); glBufferData(GL_ELEMENT_ARRAY_BUFFER, indices.size() * sizeof(unsigned short), &indices[0], GL_STATIC_DRAW); } Draw Model: Model::Draw(ICamera camera) { GLuint matrixID = glGetUniformLocation(programID, "mvp"); GLuint positionID = glGetAttribLocation(programID, "position_modelspace"); GLuint uvID = glGetAttribLocation(programID, "uv"); GLuint normalID = glGetAttribLocation(programID, "normal_modelspace"); GLuint tangentID = glGetAttribLocation(programID, "tangent_modelspace"); GLuint bitangentID = glGetAttribLocation(programID, "bitangent_modelspace"); glm::mat4 projection = camera->GetProjectionMatrix(); glm::mat4 view = camera->GetViewMatrix(); glm::mat4 model = glm::mat4(1.0f); glm::mat4 mvp = projection * view * model; glUniformMatrix4fv(matrixID, 1, GL_FALSE, &mvp[0][0]); glBindVertexArray(vertexArrayID); glEnableVertexAttribArray(positionID); glBindBuffer(GL_ARRAY_BUFFER, vertexbuffer); glVertexAttribPointer(positionID, 3, GL_FLOAT, GL_FALSE, sizeof(Vertex), &vertices[0].position); glEnableVertexAttribArray(uvID); glVertexAttribPointer(uvID, 2, GL_FLOAT, GL_FALSE, sizeof(Vertex), &vertices[0].uv); glEnableVertexAttribArray(normalID); glVertexAttribPointer(normalID, 3, GL_FLOAT, GL_FALSE, sizeof(Vertex), &vertices[0].normal); glEnableVertexAttribArray(tangentID); glVertexAttribPointer(tangentID, 3, GL_FLOAT, GL_FALSE, sizeof(Vertex), &vertices[0].tangent); glEnableVertexAttribArray(bitangentID); glVertexAttribPointer(bitangentID, 3, GL_FLOAT, GL_FALSE, sizeof(Vertex), &vertices[0].bitangent); glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, elementbuffer); glDrawElements(GL_TRIANGLES, indices.size(), GL_UNSIGNED_SHORT, (void*)0); glDisableVertexAttribArray(positionID); glDisableVertexAttribArray(uvID); glDisableVertexAttribArray(normalID); glDisableVertexAttribArray(tangentID); glDisableVertexAttribArray(bitangentID); }

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  • Separating physics and game logic from UI code

    - by futlib
    I'm working on a simple block-based puzzle game. The game play consists pretty much of moving blocks around in the game area, so it's a trivial physics simulation. My implementation, however, is in my opinion far from ideal and I'm wondering if you can give me any pointers on how to do it better. I've split the code up into two areas: Game logic and UI, as I did with a lot of puzzle games: The game logic is responsible for the general rules of the game (e.g. the formal rule system in chess) The UI displays the game area and pieces (e.g. chess board and pieces) and is responsible for animations (e.g. animated movement of chess pieces) The game logic represents the game state as a logical grid, where each unit is one cell's width/height on the grid. So for a grid of width 6, you can move a block of width 2 four times until it collides with the boundary. The UI takes this grid, and draws it by converting logical sizes into pixel sizes (that is, multiplies it by a constant). However, since the game has hardly any game logic, my game logic layer [1] doesn't have much to do except collision detection. Here's how it works: Player starts to drag a piece UI asks game logic for the legal movement area of that piece and lets the player drag it within that area Player lets go of a piece UI snaps the piece to the grid (so that it is at a valid logical position) UI tells game logic the new logical position (via mutator methods, which I'd rather avoid) I'm not quite happy with that: I'm writing unit tests for my game logic layer, but not the UI, and it turned out all the tricky code is in the UI: Stopping the piece from colliding with others or the boundary and snapping it to the grid. I don't like the fact that the UI tells the game logic about the new state, I would rather have it call a movePieceLeft() method or something like that, as in my other games, but I didn't get far with that approach, because the game logic knows nothing about the dragging and snapping that's possible in the UI. I think the best thing to do would be to get rid of my game logic layer and implement a physics layer instead. I've got a few questions regarding that: Is such a physics layer common, or is it more typical to have the game logic layer do this? Would the snapping to grid and piece dragging code belong to the UI or the physics layer? Would such a physics layer typically work with pixel sizes or with some kind of logical unit, like my game logic layer? I've seen event-based collision detection in a game's code base once, that is, the player would just drag the piece, the UI would render that obediently and notify the physics system, and the physics system would call a onCollision() method on the piece once a collision is detected. What is more common? This approach or asking for the legal movement area first? [1] layer is probably not the right word for what I mean, but subsystem sounds overblown and class is misguiding, because each layer can consist of several classes.

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  • Database Design - Surrogate keys: Part 1 of many (Rules for Surrogate Keys, E. F. Codd and C J Date

    - by tonyrogerson
    I started writing an article for my blog on surrogate keys drawing in the original research by E F Codd and C J Date, its getting a bit big :) so I'm going to chop it up into a number of posts over the coming weeks depending on my time. I'm interested in your thoughts and if you disagree please let me know but more importantly give me references back to papers stating why you take that position. Hope it makes sense. Surrogate keys There are two factions in the world of Database Design that...(read more)

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  • Workspace switching erroneously pins windows

    - by paniwani
    When switching from one workspace to the next using the Workspace switcher in the Launcher, I often see an orange square highlight, as if I am trying to pin a window to one side of the screen appear, although no window is even selected. Then after selecting a window, it is moved to the orange pinned position, which is frustrating. How do I fix this unwanted erroneous window pinning? I'm running Ubuntu 11.10. See screenshot:

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  • XNA 2D line-of-sight check

    - by bionicOnion
    I'm working on a top-down shooter in XNA, and I need to implement line-of-sight checking. I've come up with a solution that seems to work, but I get the nagging feeling that it won't be efficient enough to do every frame for multiple calls (the game already hiccups slightly at about 10 calls per frame). The code is below, but my general plan was to create a series of rectangles with a width and height of zero to act as points along the sight line, and then check to see if any of these rectangles intersects a ClutterObject (an interface I defined for things like walls or other obstacles) after first screening for any that can't possibly be in the line of sight (i.e. behind the viewer) or are too far away (a concession I made for efficiency). public static bool LOSCheck(Vector2 pos1, Vector2 pos2) { Vector2 currentPos = pos1; Vector2 perMove = (pos2 - pos1); perMove.Normalize(); HashSet<ClutterObject> clutter = new HashSet<ClutterObject>(); foreach (Room r in map.GetRooms()) { if (r != null) { foreach (ClutterObject c in r.GetClutter()) { if (c != null &&!(c.GetRectangle().X * perMove.X < 0) && !(c.GetRectangle().Y * perMove.Y < 0)) { Vector2 cVector = new Vector2(c.GetRectangle().X, c.GetRectangle().Y); if ((cVector - pos1).Length() < 1500) clutter.Add(c); } } } } while (currentPos != pos2 && ((currentPos - pos1).Length() < 1500)) { Rectangle position = new Rectangle((int)currentPos.X, (int)currentPos.Y, 0, 0); foreach (ClutterObject c in clutter) { if (position.Intersects(c.GetRectangle())) return false; } currentPos += perMove; } return true; } I'm sure that there's a better way to do this (or at least a way to make this method more efficient), but I'm not too used to XNA yet, so I figured it couldn't hurt to bring it here. At the very least, is there an efficient to determine which objects may be in front of the viewer with greater precision than the rather broad 90 degree window I've given myself?

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  • flicker when drawing 4 models for the first time

    - by Badescu Alexandru
    i have some models that i only draw at a certain moment in the game (after some seconds since the game has started). The problem is that in that first second when i start to draw the models, i see a flicker (in the sence that everything besides those models, dissapears, the background gets purple). The flicker only lasts for that frame, and then everything seems to run the way it should. UPDATE I see now that regardless of the moment i draw the models, the first frame has always the flickering aspect What could this be about? i'll share my draw method: int temp = 0; foreach (MeshObject meshObj in ShapeList) { foreach (BasicEffect effect in meshObj.mesh.Effects) { #region color elements int i = int.Parse(meshObj.mesh.Name.ElementAt(1) + ""); int j = int.Parse(meshObj.mesh.Name.ElementAt(2) + ""); int getShapeColor = shapeColorList.ElementAt(i * 4 + j); if (getShapeColor == (int)Constants.shapeColor.yellow) effect.DiffuseColor = yellow; else if (getShapeColor == (int)Constants.shapeColor.red) effect.DiffuseColor = red; else if (getShapeColor == (int)Constants.shapeColor.green) effect.DiffuseColor = green; else if (getShapeColor == (int)Constants.shapeColor.blue) effect.DiffuseColor = blue; #endregion #region lighting effect.LightingEnabled = true; effect.AmbientLightColor = new Vector3(0.25f, 0.25f, 0.25f); effect.DirectionalLight0.Enabled = true; effect.DirectionalLight0.Direction = new Vector3(-0.3f, -0.3f, -0.9f); effect.DirectionalLight0.SpecularColor = new Vector3(.7f, .7f, .7f); Vector3 v = Vector3.Normalize(new Vector3(-100, 0, -100)); effect.DirectionalLight1.Enabled = true; effect.DirectionalLight1.Direction = v; effect.DirectionalLight1.SpecularColor = new Vector3(0.6f, 0.6f, .6f); #endregion effect.Projection = camera.projectionMatrix; effect.View = camera.viewMatrix; if (meshObj.isSetInPlace == true) { effect.World = transforms[meshObj.mesh.ParentBone.Index] * gameobject.orientation; // draw in original cube-placed position meshObj.mesh.Draw(); } else { effect.World = meshObj.Orientation; // draw inSetInPlace position meshObj.mesh.Draw(); } } temp++; }

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  • My raycaster is putting out strange results, how do I fix it?

    - by JamesK89
    I'm working on a raycaster in ActionScript 3.0 for the fun of it, and as a learning experience. I've got it up and running and its displaying me output as expected however I'm getting this strange bug where rays go through corners of blocks and the edges of blocks appear through walls. Maybe somebody with more experience can point out what I'm doing wrong or maybe a fresh pair of eyes can spot a tiny bug I haven't noticed. Thank you so much for your help! Screenshots: http://i55.tinypic.com/25koebm.jpg http://i51.tinypic.com/zx5jq9.jpg Relevant code: function drawScene() { rays.graphics.clear(); rays.graphics.lineStyle(1, rgba(0x00,0x66,0x00)); var halfFov = (player.fov/2); var numRays:int = ( stage.stageWidth / COLUMN_SIZE ); var prjDist = ( stage.stageWidth / 2 ) / Math.tan(toRad( halfFov )); var angStep = ( player.fov / numRays ); for( var i:int = 0; i < numRays; i++ ) { var rAng = ( ( player.angle - halfFov ) + ( angStep * i ) ) % 360; if( rAng < 0 ) rAng += 360; var ray:Object = castRay(player.position, rAng); drawRaySlice(i*COLUMN_SIZE, prjDist, player.angle, ray); } } function drawRaySlice(sx:int, prjDist, angle, ray:Object) { if( ray.distance >= MAX_DIST ) return; var height:int = int(( TILE_SIZE / (ray.distance * Math.cos(toRad(angle-ray.angle))) ) * prjDist); if( !height ) return; var yTop = int(( stage.stageHeight / 2 ) - ( height / 2 )); if( yTop < 0 ) yTop = 0; var yBot = int(( stage.stageHeight / 2 ) + ( height / 2 )); if( yBot > stage.stageHeight ) yBot = stage.stageHeight; rays.graphics.moveTo( (ray.origin.x / TILE_SIZE) * MINI_SIZE, (ray.origin.y / TILE_SIZE) * MINI_SIZE ); rays.graphics.lineTo( (ray.hit.x / TILE_SIZE) * MINI_SIZE, (ray.hit.y / TILE_SIZE) * MINI_SIZE ); for( var x:int = 0; x < COLUMN_SIZE; x++ ) { for( var y:int = yTop; y < yBot; y++ ) { buffer.setPixel(sx+x, y, clrTable[ray.tile-1] >> ( ray.horz ? 1 : 0 )); } } } function castRay(origin:Point, angle):Object { // Return values var rTexel = 0; var rHorz = false; var rTile = 0; var rDist = MAX_DIST + 1; var rMap:Point = new Point(); var rHit:Point = new Point(); // Ray angle and slope var ra = toRad(angle) % ANGLE_360; if( ra < ANGLE_0 ) ra += ANGLE_360; var rs = Math.tan(ra); var rUp = ( ra > ANGLE_0 && ra < ANGLE_180 ); var rRight = ( ra < ANGLE_90 || ra > ANGLE_270 ); // Ray position var rx = 0; var ry = 0; // Ray step values var xa = 0; var ya = 0; // Ray position, in map coordinates var mx:int = 0; var my:int = 0; var mt:int = 0; // Distance var dx = 0; var dy = 0; var ds = MAX_DIST + 1; // Horizontal intersection if( ra != ANGLE_180 && ra != ANGLE_0 && ra != ANGLE_360 ) { ya = ( rUp ? TILE_SIZE : -TILE_SIZE ); xa = ya / rs; ry = int( origin.y / TILE_SIZE ) * ( TILE_SIZE ) + ( rUp ? TILE_SIZE : -1 ); rx = origin.x + ( ry - origin.y ) / rs; mx = 0; my = 0; while( mx >= 0 && my >= 0 && mx < world.size.x && my < world.size.y ) { mx = int( rx / TILE_SIZE ); my = int( ry / TILE_SIZE ); mt = getMapTile(mx,my); if( mt > 0 && mt < 9 ) { dx = rx - origin.x; dy = ry - origin.y; ds = ( dx * dx ) + ( dy * dy ); if( rDist >= MAX_DIST || ds < rDist ) { rDist = ds; rTile = mt; rMap.x = mx; rMap.y = my; rHit.x = rx; rHit.y = ry; rHorz = true; rTexel = int(rx % TILE_SIZE) } break; } rx += xa; ry += ya; } } // Vertical intersection if( ra != ANGLE_90 && ra != ANGLE_270 ) { xa = ( rRight ? TILE_SIZE : -TILE_SIZE ); ya = xa * rs; rx = int( origin.x / TILE_SIZE ) * ( TILE_SIZE ) + ( rRight ? TILE_SIZE : -1 ); ry = origin.y + ( rx - origin.x ) * rs; mx = 0; my = 0; while( mx >= 0 && my >= 0 && mx < world.size.x && my < world.size.y ) { mx = int( rx / TILE_SIZE ); my = int( ry / TILE_SIZE ); mt = getMapTile(mx,my); if( mt > 0 && mt < 9 ) { dx = rx - origin.x; dy = ry - origin.y; ds = ( dx * dx ) + ( dy * dy ); if( rDist >= MAX_DIST || ds < rDist ) { rDist = ds; rTile = mt; rMap.x = mx; rMap.y = my; rHit.x = rx; rHit.y = ry; rHorz = false; rTexel = int(ry % TILE_SIZE); } break; } rx += xa; ry += ya; } } return { angle: angle, distance: Math.sqrt(rDist), hit: rHit, map: rMap, tile: rTile, horz: rHorz, origin: origin, texel: rTexel }; }

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  • Premier SDK pour Bada, le nouvel OS de Samsung fodée sur Linux qui équipera un tiers des smartphones

    Mise à jour du 10/05/10 Premier SDK pour Bada Le tout nouvel OS de Samsung qui essaye d'exploiter sa position dominante sur le marché des smartphones Il y a peu, Samsung a décidé de se lancer dans la conception d'un système d'exploitation pour ses terminaux mobiles (lire par ailleur : « Nokia lance Meego en collaboration avec Intel, Samsung présente Bada »). Bada va aujourd'hui pouvoir passer le test des développeurs puisque le constructe...

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  • XChat window start with bottom edge covered

    - by jasmines
    When I start Xchat, I note the issue: As you can see, the bottom edge of the window is covered by some other thing (in this case, it's firefox status bar, but if I have no other window opened, I see my desktop background in that position), so I reduce it with the maximize button on top left: Finally I maximize it again and obtain the wanted behaviour: Is this a bug or can I adjust it in any way?

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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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  • Overwrite previous output in Bash instead of appending it

    - by NES
    For a bash timer i use this code: #!/bin/bash sek=60 echo "60 Seconds Wait!" echo -n "One Moment please " while [ $sek -ge 1 ] do echo -n "$sek " sleep 1 sek=$[$sek-1] done echo echo "ready!" That gives me something like that One Moment please: 60 59 58 57 56 55 ... Is there a possibility to replace the last value of second by the most recent so that the output doesn't generate a large trail but the seconds countdown like a real time at one position? (Hope you understand what i mean :))

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  • Using Ogre particle point billboards with shaders

    - by Jay
    I'm learning about using Ogre particles and had some questions about how the point type particles work. Q. I believe point type particles are implemented as a single position. Is one single vertex is passed to the vertex shader? Q. If one vertex is passed to the vertex shader then what gets sent to the fragment shader? Q. Can I pass the particle size to the shader? Perhaps with a custom parameter?

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  • Routes on a sphere surface - Find geodesic?

    - by CaNNaDaRk
    I'm working with some friends on a browser based game where people can move on a 2D map. It's been almost 7 years and still people play this game so we are thinking of a way to give them something new. Since then the game map was a limited plane and people could move from (0, 0) to (MAX_X, MAX_Y) in quantized X and Y increments (just imagine it as a big chessboard). We believe it's time to give it another dimension so, just a couple of weeks ago, we began to wonder how the game could look with other mappings: Unlimited plane with continous movement: this could be a step forward but still i'm not convinced. Toroidal World (continous or quantized movement): sincerely I worked with torus before but this time I want something more... Spherical world with continous movement: this would be great! What we want Users browsers are given a list of coordinates like (latitude, longitude) for each object on the spherical surface map; browsers must then show this in user's screen rendering them inside a web element (canvas maybe? this is not a problem). When people click on the plane we convert the (mouseX, mouseY) to (lat, lng) and send it to the server which has to compute a route between current user's position to the clicked point. What we have We began writing a Java library with many useful maths to work with Rotation Matrices, Quaternions, Euler Angles, Translations, etc. We put it all together and created a program that generates sphere points, renders them and show them to the user inside a JPanel. We managed to catch clicks and translate them to spherical coords and to provide some other useful features like view rotation, scale, translation etc. What we have now is like a little (very little indeed) engine that simulates client and server interaction. Client side shows points on the screen and catches other interactions, server side renders the view and does other calculus like interpolating the route between current position and clicked point. Where is the problem? Obviously we want to have the shortest path to interpolate between the two route points. We use quaternions to interpolate between two points on the surface of the sphere and this seemed to work fine until i noticed that we weren't getting the shortest path on the sphere surface: We though the problem was that the route is calculated as the sum of two rotations about X and Y axis. So we changed the way we calculate the destination quaternion: We get the third angle (the first is latitude, the second is longitude, the third is the rotation about the vector which points toward our current position) which we called orientation. Now that we have the "orientation" angle we rotate Z axis and then use the result vector as the rotation axis for the destination quaternion (you can see the rotation axis in grey): What we got is the correct route (you can see it lays on a great circle), but we get to this ONLY if the starting route point is at latitude, longitude (0, 0) which means the starting vector is (sphereRadius, 0, 0). With the previous version (image 1) we don't get a good result even when startin point is 0, 0, so i think we're moving towards a solution, but the procedure we follow to get this route is a little "strange" maybe? In the following image you get a view of the problem we get when starting point is not (0, 0), as you can see starting point is not the (sphereRadius, 0, 0) vector, and as you can see the destination point (which is correctly drawn!) is not on the route. The magenta point (the one which lays on the route) is the route's ending point rotated about the center of the sphere of (-startLatitude, 0, -startLongitude). This means that if i calculate a rotation matrix and apply it to every point on the route maybe i'll get the real route, but I start to think that there's a better way to do this. Maybe I should try to get the plane through the center of the sphere and the route points, intersect it with the sphere and get the geodesic? But how? Sorry for being way too verbose and maybe for incorrect English but this thing is blowing my mind! EDIT: This code version is related to the first image: public void setRouteStart(double lat, double lng) { EulerAngles tmp = new EulerAngles ( Math.toRadians(lat), 0, -Math.toRadians(lng)); //set route start Quaternion qtStart.setInertialToObject(tmp); //do other stuff like drawing start point... } public void impostaDestinazione(double lat, double lng) { EulerAngles tmp = new AngoliEulero( Math.toRadians(lat), 0, -Math.toRadians(lng)); qtEnd.setInertialToObject(tmp); //do other stuff like drawing dest point... } public V3D interpolate(double totalTime, double t) { double _t = t/totalTime; Quaternion q = Quaternion.Slerp(qtStart, qtEnd, _t); RotationMatrix.inertialQuatToIObject(q); V3D p = matInt.inertialToObject(V3D.Xaxis.scale(sphereRadius)); //other stuff, like drawing point ... return p; } //mostly taken from a book! public static Quaternion Slerp(Quaternion q0, Quaternion q1, double t) { double cosO = q0.dot(q1); double q1w = q1.w; double q1x = q1.x; double q1y = q1.y; double q1z = q1.z; if (cosO < 0.0f) { q1w = -q1w; q1x = -q1x; q1y = -q1y; q1z = -q1z; cosO = -cosO; } double sinO = Math.sqrt(1.0f - cosO*cosO); double O = Math.atan2(sinO, cosO); double oneOverSinO = 1.0f / senoOmega; k0 = Math.sin((1.0f - t) * O) * oneOverSinO; k1 = Math.sin(t * O) * oneOverSinO; // Interpolate return new Quaternion( k0*q0.w + k1*q1w, k0*q0.x + k1*q1x, k0*q0.y + k1*q1y, k0*q0.z + k1*q1z ); } A little dump of what i get (again check image 1): Route info: Sphere radius and center: 200,000, (0.0, 0.0, 0.0) Route start: lat 0,000 °, lng 0,000 ° @v: (200,000, 0,000, 0,000), |v| = 200,000 Route end: lat 30,000 °, lng 30,000 ° @v: (150,000, 86,603, 100,000), |v| = 200,000 Qt dump: (w, x, y, z), rot. angle°, (x, y, z) rot. axis Qt start: (1,000, 0,000, -0,000, 0,000); 0,000 °; (1,000, 0,000, 0,000) Qt end: (0,933, 0,067, -0,250, 0,250); 42,181 °; (0,186, -0,695, 0,695) Route start: lat 30,000 °, lng 10,000 ° @v: (170,574, 30,077, 100,000), |v| = 200,000 Route end: lat 80,000 °, lng -50,000 ° @v: (22,324, -26,604, 196,962), |v| = 200,000 Qt dump: (w, x, y, z), rot. angle°, (x, y, z) rot. axis Qt start: (0,962, 0,023, -0,258, 0,084); 31,586 °; (0,083, -0,947, 0,309) Qt end: (0,694, -0,272, -0,583, -0,324); 92,062 °; (-0,377, -0,809, -0,450)

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  • Microsoft turning into a toothless tiger?

    <b>Technology & Life Integrationt:</b> "Many moons ago ( and I am not talking about those drunken moons at passing cars :), while the IT jungle was still fresh and green. There was a big blue king of the jungle. This top monkey position was usurped by an up and coming tiger that, while the tigers name seemed small and soft, it wasn't afraid to show its teeth."

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  • Choosing between two programmers: experience vs. passion

    - by Duke
    I am in a position where I have to hire a programmer and have the option of 2 candidates, the first has experience but he doesn't have a passion for coding and he says so while the second doesn't have the experience but he has the passion, he did well in the interview and is certified. We have the resources to train someone, but I really don't want to blow this process and hire someone who will be disappointing can anyone help me as to how to approach this situation.

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  • OpenGL - Calculating camera view matrix

    - by Karle
    Problem I am calculating the model, view and projection matrices independently to be used in my shader as follows: gl_Position = projection * view * model * vec4(in_Position, 1.0); When I try to calculate my camera's view matrix the Z axis is flipped and my camera seems like it is looking backwards. My program is written in C# using the OpenTK library. Translation (Working) I've created a test scene as follows: From my understanding of the OpenGL coordinate system they are positioned correctly. The model matrix is created using: Matrix4 translation = Matrix4.CreateTranslation(modelPosition); Matrix4 model = translation; The view matrix is created using: Matrix4 translation = Matrix4.CreateTranslation(-cameraPosition); Matrix4 view = translation; Rotation (Not-Working) I now want to create the camera's rotation matrix. To do this I use the camera's right, up and forward vectors: // Hard coded example orientation: // Normally calculated from up and forward // Similar to look-at camera. Vector3 r = Vector.UnitX; Vector3 u = Vector3.UnitY; Vector3 f = -Vector3.UnitZ; Matrix4 rot = new Matrix4( r.X, r.Y, r.Z, 0, u.X, u.Y, u.Z, 0, f.X, f.Y, f.Z, 0, 0.0f, 0.0f, 0.0f, 1.0f); This results in the following matrix being created: I know that multiplying by the identity matrix would produce no rotation. This is clearly not the identity matrix and therefore will apply some rotation. I thought that because this is aligned with the OpenGL coordinate system is should produce no rotation. Is this the wrong way to calculate the rotation matrix? I then create my view matrix as: // OpenTK is row-major so the order of operations is reversed: Matrix4 view = translation * rot; Rotation almost works now but the -Z/+Z axis has been flipped, with the green cube now appearing closer to the camera. It seems like the camera is looking backwards, especially if I move it around. My goal is to store the position and orientation of all objects (including the camera) as: Vector3 position; Vector3 up; Vector3 forward; Apologies for writing such a long question and thank you in advance. I've tried following tutorials/guides from many sites but I keep ending up with something wrong. Edit: Projection Matrix Set-up Matrix4 projection = Matrix4.CreatePerspectiveFieldOfView( (float)(0.5 * Math.PI), (float)display.Width / display.Height, 0.1f, 1000.0f);

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  • The View-Matrix and Alternative Calculations

    - by P. Avery
    I'm working on a radiosity processor in DirectX 9. The process requires that the camera be placed at the center of a mesh face and a 'screenshot' be taken facing 5 different directions...forward...up...down...left...right... ...The problem is that when the mesh face is facing up( look vector: 0, 1, 0 )...a view matrix cannot be determined using standard trigonometry functions: Matrix4 LookAt( Vector3 eye, Vector3 target, Vector3 up ) { // The "look-at" vector. Vector3 zaxis = normal(target - eye); // The "right" vector. Vector3 xaxis = normal(cross(up, zaxis)); // The "up" vector. Vector3 yaxis = cross(zaxis, xaxis); // Create a 4x4 orientation matrix from the right, up, and at vectors Matrix4 orientation = { xaxis.x, yaxis.x, zaxis.x, 0, xaxis.y, yaxis.y, zaxis.y, 0, xaxis.z, yaxis.z, zaxis.z, 0, 0, 0, 0, 1 }; // Create a 4x4 translation matrix by negating the eye position. Matrix4 translation = { 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, -eye.x, -eye.y, -eye.z, 1 }; // Combine the orientation and translation to compute the view matrix return ( translation * orientation ); } The above function comes from http://3dgep.com/?p=1700... ...Is there a mathematical approach to this problem? Edit: A problem occurs when setting the view matrix to up or down directions, here is an example of the problem when facing down: D3DXVECTOR4 vPos( 3, 3, 3, 1 ), vEye( 1.5, 3, 3, 1 ), vLook( 0, -1, 0, 1 ), vRight( 1, 0, 0, 1 ), vUp( 0, 0, 1, 1 ); D3DXMATRIX mV, mP; D3DXMatrixPerspectiveFovLH( &mP, D3DX_PI / 2, 1, 0.5f, 2000.0f ); D3DXMatrixIdentity( &mV ); memcpy( ( void* )&mV._11, ( void* )&vRight, sizeof( D3DXVECTOR3 ) ); memcpy( ( void* )&mV._21, ( void* )&vUp, sizeof( D3DXVECTOR3 ) ); memcpy( ( void* )&mV._31, ( void* )&vLook, sizeof( D3DXVECTOR3 ) ); memcpy( ( void* )&mV._41, ( void* )&(-vEye), sizeof( D3DXVECTOR3 ) ); D3DXVec4Transform( &vPos, &vPos, &( mV * mP ) ); Results: vPos = D3DXVECTOR3( 1.5, -6, -0.5, 0 ) - this vertex is not properly processed by shader as the homogenous w value is 0 it cannot be normalized to a position within device space...

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  • FAQ: GridView Calculation with JavaScript - Editable Price Field

    - by Vincent Maverick Durano
    Recently I wrote a series of blog posts that demonstrates how to do calculation in GridView using JavaScripts. You can check the series of posts below: FAQ: GridView Calculation with JavaScript FAQ: GridView Calculation with JavaScript - Formatting and Validation FAQ: GridView Calculation with JavaScript - Displaying Quantity Total Recently a user in the forums is asking how to calculate the total quantity, sub-totals and total amout in GridView  when a user enters the price and quantity in the TextBox field. Obviously the series of post  that I wrote will not work in this case because the price field in those examples are Label (read-only) and not TextBox fields. In this post I'm going to demonstrate how to accomplish this using the same method used in my previous examples. Basically I'm just going to modify the GridView declaration and replace the Label price field with a TextBox so that users can type on it. And finally modify the CalculateTotals() javascript function. Here are the code blocks below: <html xmlns="http://www.w3.org/1999/xhtml" > <head runat="server"> <title></title> <script type="text/javascript"> function CalculateTotals() { var gv = document.getElementById("<%= GridView1.ClientID %>"); var tb = gv.getElementsByTagName("input"); var lb = gv.getElementsByTagName("span"); var sub = 0; var total = 0; var indexQ = 1; var indexP = 0; var price = 0; var qty = 0; var totalQty = 0; var tbCount = tb.length / 2; for (var i = 0; i < tbCount; i++) { if (tb[i].type == "text") { ValidateNumber(tb[i + indexQ]); sub = parseFloat(tb[i + indexP].value) * parseFloat(tb[i + indexQ].value); if (isNaN(sub)) { lb[i].innerHTML = "0.00"; sub = 0; } else { lb[i].innerHTML = FormatToMoney(sub, "$", ",", "."); ; } if (isNaN(tb[i + indexQ].value) || tb[i + indexQ].value == "") { qty = 0; } else { qty = tb[i + indexQ].value; } totalQty += parseInt(qty); total += parseFloat(sub); indexQ++; indexP++; } } lb[lb.length - 2].innerHTML = totalQty; lb[lb.length -1].innerHTML = FormatToMoney(total, "$", ",", "."); } function ValidateNumber(o) { if (o.value.length > 0) { o.value = o.value.replace(/[^\d]+/g, ''); //Allow only whole numbers } } function isThousands(position) { if (Math.floor(position / 3) * 3 == position) return true; return false; }; function FormatToMoney(theNumber, theCurrency, theThousands, theDecimal) { var theDecimalDigits = Math.round((theNumber * 100) - (Math.floor(theNumber) * 100)); theDecimalDigits = "" + (theDecimalDigits + "0").substring(0, 2); theNumber = "" + Math.floor(theNumber); var theOutput = theCurrency; for (x = 0; x < theNumber.length; x++) { theOutput += theNumber.substring(x, x + 1); if (isThousands(theNumber.length - x - 1) && (theNumber.length - x - 1 != 0)) { theOutput += theThousands; }; }; theOutput += theDecimal + theDecimalDigits; return theOutput; } </script> </head> <body> <form id="form1" runat="server"> <asp:gridview ID="GridView1" runat="server" ShowFooter="true" AutoGenerateColumns="false"> <Columns> <asp:BoundField DataField="RowNumber" HeaderText="Row Number" /> <asp:BoundField DataField="Description" HeaderText="Item Description" /> <asp:TemplateField HeaderText="Item Price"> <ItemTemplate> <asp:TextBox ID="TXTPrice" runat="server" onkeyup="CalculateTotals();"></asp:TextBox> </ItemTemplate> <FooterTemplate> <b>Total Qty:</b> </FooterTemplate> </asp:TemplateField> <asp:TemplateField HeaderText="Quantity"> <ItemTemplate> <asp:TextBox ID="TXTQty" runat="server" onkeyup="CalculateTotals();"></asp:TextBox> </ItemTemplate> <FooterTemplate> <asp:Label ID="LBLQtyTotal" runat="server" Font-Bold="true" ForeColor="Blue" Text="0" ></asp:Label>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <b>Total Amount:</b> </FooterTemplate> </asp:TemplateField> <asp:TemplateField HeaderText="Sub-Total"> <ItemTemplate> <asp:Label ID="LBLSubTotal" runat="server" ForeColor="Green" Text="0.00"></asp:Label> </ItemTemplate> <FooterTemplate> <asp:Label ID="LBLTotal" runat="server" ForeColor="Green" Font-Bold="true" Text="0.00"></asp:Label> </FooterTemplate> </asp:TemplateField> </Columns> </asp:gridview> </form> </body> </html>   That's it! I hope someone find this post useful! Technorati Tags: ASP.NET,GridView,JavaScript

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