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  • Drawing a texture line between two vectors in XNA WP7

    - by Krav
    I want to create a simple graph maker in WP7. The goal is to draw a texture line between two vectors what the user defines with touch. I already made the rotation, and it is working, but not correctly, because it doesn't calculate the line's texture height, and because of that, there are too many overlapping textures. So it does draw the line, but too many of them. How could I calculate it correctly? Here is the code: public void DrawLine(Vector2 st,Vector2 dest,NodeUnit EdgeParent,NodeUnit EdgeChild) { float d = Vector2.Distance(st, dest); float rotate = (float)(Math.Atan2(st.Y - dest.Y, st.X - dest.X)); direction = new Vector2(((dest.X - st.X) / (float)d), (dest.Y - st.Y) / (float)d); Vector2 _pos = st; World.TheHive.Add(new LineHiveMind(linetexture, _pos, rotate, EdgeParent, EdgeChild,new List<LineUnit>())); for (int i = 0; i < d; i++) { World.TheHive.Last()._lines.Add(new LineUnit(linetexture, _pos, rotate, EdgeParent, EdgeChild)); _pos += direction; } } d is for the Distance of the st (Starting node) and dest (Destination node) rotate is for rotation direction calculates the direction between the starting and the destination node _pos is for starting position changing Thanks for any suggestions/help!

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  • Implementing my Entity System. Questions about some problems I have found.

    - by Notbad
    Hi!, Well during this week I have deciding about implementation of my entity system. It is a big topic so it has been difficult to take one option from the whole. This has been my decision: 1) I don't have an entity class it is just an id. 2) I have systems that contain a list of components (the list is homegenous, I mean, RenderSystem will just have RenderComponents). 3) Compones will be just data. 4) There would be some kind of "entity prototypes" in a manager or something from we will create entity instances.Ideally they will define the type of components it has and initialization data. 5) Prototype code to create an entity (this is from the top of my head): int id=World::getInstance()->createEntity("entity template"); 6) This will notify all systems that a new entity has been created, and if the entity needs a component that the system handles it will add it to the entity. Ok, this are the ideas. Let's see if some can help with the problems: 1) The main problem is this templates that are sent to the systems in creation process to populate the entity with needed components. What would you use, an OR(ed) int?, a list of strings?. 2) How to do initialization for components when the entity has been created? How to store this in the template? I have thought about having a function in the template that is virtual and after entity is created an populated, gets the components and sets initialization values. 3) Don't you think this is a lot of work for just an entity creation?. Sorry for the long post, I have tried to expose my ideas and finding in order other could have a start beside exposing my problems. Thanks in advance, Notbad.

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  • Estimating costs in a GOAP system

    - by fullwall
    I'm currently developing a GOAP system in Java. An explanation of GOAP can be found at http://web.media.mit.edu/~jorkin/goap.html. Essentially, it's using A* to plot between Actions that mutate the world state. To provide a fair chance for all Actions and Goals to execute, I'm using a heuristic function to estimate the cost of doing something. What is the best way to estimate this cost so that it is comparable to all the other costs? As an example, estimating the cost of running away from an enemy versus attacking it - how should the cost be calculated to be comparable?

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  • Wall avoidance steering

    - by Vodemki
    I making a small steering simulator using the reynolds boid algorythm. Now I want to add a wall avoidance feature. My walls are in 3D and defined using two points like that: ---------. P2 | | P1 .--------- My agents have a velocity, a position, etc... Could you tell me how to make avoidance with my agents ? Vector2D ReynoldsSteeringModel::repulsionFromWalls() { Vector2D force; vector<Wall *> wallsList = walls(); Point2D pos = self()->position(); Vector2D velocity = self()->velocity(); for (unsigned i=0; i<wallsList.size(); i++) { //TODO } return force; } Then I use all the forces returned by my boid functions and I apply it to my agent. I just need to know how to do that with my walls ? Thanks for your help.

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  • Best approach to get clicked objects from a display list (2D)

    - by Ixx
    I'm implementing a display list to manage my visuals on screen. I want to know which object is clicked. My objects already have z-order variable. With my current knowledge (almost nothing) the only thing which comes to my mind is make a linear search and get all the objects which contains the clicked point. And then select the object with the highest z-order. But I know there are far better approaches. I think it's something with trees (binary search?). - container display objects and search recursively? just don't know where to start looking, for this concrete case. Any hint link or concrete solution is welcome.

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  • rotate opengl mesh relative to camera

    - by shuall
    I have a cube in opengl. It's position is determined by multiplying it's specific model matrix, the view matrix, and the projection matrix and then passing that to the shader as per this tutorial (http://www.opengl-tutorial.org/beginners-tutorials/tutorial-3-matrices/). I want to rotate it relative to the camera. The only way I can think of getting the correct axis is by multiplying the inverse of the model matrix (because that's where all the previous rotations and tranforms are stored) times the view matrix times the axis of rotation (x or y). I feel like there's got to be a better way to do this like use something other than model, view and projection matrices, or maybe I'm doing something wrong. That's what all the tutorials I've seen use. PS I'm also trying to keep with opengl 4 core stuff. edit: If quaternions would fix my problems, could someone point me to a good tutorial/example for switching from 4x4 matrices to quaternions. I'm a little daunted by the task.

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  • RasterizerState set to null after calling DrawText in Nuclex

    - by ProgrammerAtWork
    I have the following code in XNA: // class members Text t1; Text t2; Text t3; // init // Debugfont is size 24 vectorfont t1 = MM.DebugFont24.Fill("hello"); t1 = MM.DebugFont24.Extrude("hello"); t2 = MM.DebugFont24.Fill("hello"); t2 = MM.DebugFont24.Extrude("hello"); t3 = MM.DebugFont24.Fill("hello"); t3 = MM.DebugFont24.Extrude("hello"); // Draw TextBatch test = new TextBatch(MM.GD); test.DrawText(t1, Color.Red); test.DrawText(t2, Color.Red); test.DrawText(t3, Color.Red); test.End(); //After the second call to the TextBatch, RasterizerState of the GraphicsDevice is set to null //But I don't get any runtime errors or any indication of that something is wrong. Is this supposed to happen? Or am I doing something wrong? I've discovered that this happened because culling was set to None when I was rendering textures

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  • Getting the front buffer into a gfx mem surface (Dx9)

    - by lapin
    I'm using DirectX 9 to acquire the frontbuffer. There are a couple of ways I know of to get at the front buffer: GetRenderTargetData() GetFrontBufferData() The MSDN page on both of these API calls state that the data is copied from device memory to system memory. I'd like to copy the front buffer surface directly to another graphics memory surface, as I have other manipulations to perform on the acquired surface before returning it to system memory. I'm creating a D3DUSAGE_DYNAMIC texture (gfx mem texture) and calling GetFrontBufferData() to write the front buffer to my textures surface0. Is this valid? Will the operation remain in gfx memory, or will it need to move to system memory and then back to graphics memory? If this is the case, is what I'm trying to achieve possible?

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  • Portal View/Projection Matrix near plane

    - by melak47
    For RenderToTexture/Camera based portal rendering, the basics seems simple enough. However, with a free camera, most of the time it is going to be looking at such portals at an angle: Now a regular near clipping plane will not always work here, it will either intersect with the wall the portal is sitting on, or possibly with objects in front of the wall. The desired near clipping plane would be aligned like the portal, producing a view volume more like this: or this in 3D: So here is my question: How does one construct or "truncate" a view/projection matrix to achieve such an off-camera-normal (near) clipping plane?

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  • Scene transitions

    - by Mars
    It's my first time working with actual scenes/states, aka DrawableGameComponents, which work separate from one another. I'm now wondering what's the best way to make transitions between them, and how to affect them from other scenes. Lets say I wanted to "push" one screen to the right, with another one coming in at the same time. Naturally I'd have to keep drawing both, until the transition is complete. And I'd have to adjust the coordinates I'm drawing at while doing it. Is there a way around specifically handling this special case in every single scene? Or of I wanted to fade one into the other. Basically the question stays the same, how would you do that without having to handle it in every single scene? While writing this I'm realizing it will be the same thing for all kinds of transitions. Maybe a central Draw method in the manager could be a solution, where parameters and effects are applied when necessary. But this wouldn't work if objects that are drawn have their own method, and aren't drawn within the scene, or if an effect has to be applied to the whole scene. That means, maybe scenes have to be drawn to their own rendertarget? That way one call to the base class after the normal drawing could be enough, to apply the effects, while drawing it to the main render target. But I once heard there are problems when switching from target to target, back and forth. So is that even a viable option? As you can see, I have some basic ideas how it might work... but nothing specific. I'd like to learn what's the common way to achieve such things, a general way to apply all kinds of transitions.

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  • BoundingSpheres move when they should not

    - by NDraskovic
    I have a XNA 4.0 project in which I load a file that contains type and coordinates of items I need to draw to the screen. Also I need to check if one particular type (the only movable one) is passing in front or trough other items. This is the code I use to load the configuration: if (ks.IsKeyDown(Microsoft.Xna.Framework.Input.Keys.L)) { this.GraphicsDevice.Clear(Color.CornflowerBlue); Otvaranje.ShowDialog(); try { using (StreamReader sr = new StreamReader(Otvaranje.FileName)) { String linija; while ((linija = sr.ReadLine()) != null) { red = linija.Split(','); model = red[0]; x = red[1]; y = red[2]; z = red[3]; elementi.Add(Convert.ToInt32(model)); podatci.Add(new Vector3(Convert.ToSingle(x), Convert.ToSingle(y), Convert.ToSingle(z))); sfere.Add(new BoundingSphere(new Vector3(Convert.ToSingle(x), Convert.ToSingle(y), Convert.ToSingle(z)), 1f)); } } } catch (Exception ex) { Window.Title = ex.ToString(); } } The "Otvaranje" is an OpenFileDialog object, "elementi" is a List (determines the type of item that would be drawn), podatci is a List (determines the location where the items will be drawn) and sfere is a List. Now I solved the picking algorithm (checking for ray and bounding sphere intersection) and it works fine, but the collision detection does not. I noticed, while using picking, that BoundingSphere's move even though the objects that they correspond to do not. The movable object is drawn to the world1 Matrix, and the static objects are drawn into the world2 Matrix (world1 and world2 have the same values, I just separated them so that the static elements would not move when the movable one does). The problem is that when I move the item I want, all boundingSpheres move accordingly. How can I move only the boundingSphere that corresponds to that particular item, and leave the rest where they are?

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  • How to prevent "underwater sight" in games

    - by CPP_Person
    In many games where the player can go underwater, it seems like when you look where the top half of the screen is in the air, and the bottom half the screen is in the water, it's almost like the water doesn't exist and the player is... flying slowly with water sounds? Is there a logical way to solve this? An algorithm? Doesn't seem like any solution has come up yet since many games still have this. I don't want to make the same mistake.

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  • How can I get textures on edge of walls like in Super Metroid and Aquaria?

    - by meds
    Games like Super Metroid and Aquaria present the terrain with the other facing parts having rocks and stuff while deeper behind them (i.e. underground) there's different detail or just black. I would like to do something similar using polygons. Terrain is created in my current level as a set of overlapping square boxes. I'm not sure if this rendering method will work such a system for creating terrain but if anyone has ideas I'd love to hear them. Otherwise I'd like to know how I should re-write the terrain rendering system so it actually works to draw terrain in this manner...

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  • Are there any OpenGL ES 2.0 examples for JOGL?

    - by fjdutoit
    I've scoured the internet for the last few hours looking for an example of how to run even the most basic OpenGL ES 2 example using JOGL but "by Jupiter!" it has been a total fail. I tried converting the android example from the OpenGL ES 2.0 Programming Guide examples (and at the same time looking at the WebGL example -- which worked fine) yet without any success. Are there any examples out there? If anyone else wants some extra help regarding this question see this thread on the official Jogamp forum.

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  • Material tiling and offset in unity

    - by Simran kaur
    Ambiguity: What exactly is the difference between Tiling the material and Offset of material? Need to do: I need the material to be repeated n times on the object where I need to set the value of n via script.How do I do it? It seems to happen through Tiling(tried via inspector) but again what is difference between mainTextureOffset and setTextureOffset? Tried: Following is the line of code that I tried to repeat the texture n number of times on an object(repeat across the width of object), but it does nothing significant that I can see.

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  • Generating and rendering not point-like particles on GPU

    - by TravisG
    Specifically I'm talking about particles as seen (for example) in the UE4 dev video here. They're not just points and seem to have a nice shape to them that seems to follow their movement. Is it possible to create these kinds of particles (efficiently) completely on the GPU (perhaps through something like motion? Or is the only (or most efficient) way to just create a small particle texture and render small quads for each particle?

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  • Drawing Grid in 3D view - Mathematically calculate points and draw line between them (Not working)

    - by Deukalion
    I'm trying to draw a simple grid from a starting point and expand it to a size. Doing this mathematically and drawing the lines between each point, but since the "DrawPrimitives(LineList)" doesn't work the way it should work, And this method can't even draw lines between four points to create a simple Rectangle, so how does this method work exactly? Some sort of coordinate system: [ ][ ][ ][ ][ ][ ][ ] [ ][2.2][ ][0.2][ ][2.2][ ] [ ][2.1][1.1][ ][1.1][2.1][ ] [ ][2.0][ ][0.0][ ][2.0][ ] [ ][2.1][1.1][ ][1.1][2.1][ ] [ ][2.2][ ][0.2][ ][2.2][ ] [ ][ ][ ][ ][ ][ ][ ] I've checked with my method and it's working as it should. It calculates all the points to form a grid. This way I should be able to create Points where to draw line right? This way, if I supply the method with Size = 2 it starts at 0,0 and works it through all the corners (2,2) on each side. So, I have the positions of each point. How do I draw lines between these? VerticeCount = must be number of Points in this case, right? So, tell me, if I can't supply this method with Point A, Point B, Point C, Point D to draw a four vertice rectangle (Point A - B - C - D) - how do I do it? How do I even begin to understand it? As far as I'm concered, that's a "Line list" or a list of points where to draw lines. Can anyone explain what I'm missing? I wish to do this mathematically so I can create a a custom grid that can be altered.

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  • How to offset particles from point of origin

    - by Sun
    Hi I'm having troubles off setting particles from a point of origin. I want my particles to spread out after a certain radius from a the point of origin. For example, this is what I have right now: All particles emitted from a point of origin. What I want is this: Particles are offset from the point of origin by some amount, i.e after the circle. What is the best way to achieve this? At the moment, I have the point of origin, the position of each particle and its rotation angle. Sorry for the poor illustrations. Edit: I was mistaken, when a particle is created, I have only the point of origin. When the particle is created I am able to calculate the rotation of the particle in the update method after it has moved to a new location using atan2() method. This is how I create/manage particles: Created new particle at enemy ship death location, for every new particle which is added to the list, call Update and Draw to update its position, calculate new angle and draw it.

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  • In what kind of variable type is the player position stored on a MMORPG such as WoW?

    - by jokoon
    I even heard J. Carmack quickly talk about it... How a software can track a player's position so accurately, being on a such huge world, without loading between zones, and on a multiplayer scale ? How is the data formatted when it passes through the netcode ? I can understand how vertices are stored into the graphic card's memory, but when it comes to synchronize the multiplayer, I can't imagine what is best.

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  • How do I put different textures on different walls? LWJGL

    - by lehermj
    So far I have it so you are running around in a box, but all of the walls are the same texture! I've loaded up other textures for the walls (I want the walls a different texture than the floor) but it seems as if its being ignored... Here's my code: int floorTexture = glGenTextures(); { InputStream in = null; try { in = new FileInputStream("floor.png"); PNGDecoder decoder = new PNGDecoder(in); ByteBuffer buffer = BufferUtils.createByteBuffer(4 * decoder.getWidth() * decoder.getHeight()); decoder.decode(buffer, decoder.getWidth() * 4, Format.RGBA); buffer.flip(); glBindTexture(GL_TEXTURE_2D, floorTexture); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST); glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, decoder.getWidth(), decoder.getHeight(), 0, GL_RGBA, GL_UNSIGNED_BYTE, buffer); glBindTexture(GL_TEXTURE_2D, floorTexture); } catch (FileNotFoundException ex) { System.err.println("Failed to find the texture files."); ex.printStackTrace(); Display.destroy(); System.exit(1); } catch (IOException ex) { System.err.println("Failed to load the texture files."); ex.printStackTrace(); Display.destroy(); System.exit(1); } finally { if (in != null) { try { in.close(); } catch (IOException e) { e.printStackTrace(); } } } } int wallTexture = glGenTextures(); { InputStream in = null; try { in = new FileInputStream("walls.png"); PNGDecoder decoder = new PNGDecoder(in); ByteBuffer buffer = BufferUtils.createByteBuffer(4 * decoder.getWidth() * decoder.getHeight()); decoder.decode(buffer, decoder.getWidth() * 4, Format.RGBA); buffer.flip(); glBindTexture(GL_TEXTURE_2D, wallTexture); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST); glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, decoder.getWidth(), decoder.getHeight(), 0, GL_RGBA, GL_UNSIGNED_BYTE, buffer); glBindTexture(GL_TEXTURE_2D, wallTexture); } catch (FileNotFoundException ex) { System.err.println("Failed to find the texture files."); ex.printStackTrace(); Display.destroy(); System.exit(1); } catch (IOException ex) { System.err.println("Failed to load the texture files."); ex.printStackTrace(); Display.destroy(); System.exit(1); } finally { if (in != null) { try { in.close(); } catch (IOException e) { e.printStackTrace(); } } } } int ceilingDisplayList = glGenLists(1); glNewList(ceilingDisplayList, GL_COMPILE); glBegin(GL_QUADS); glTexCoord2f(0, 0); glVertex3f(-gridSize, ceilingHeight, -gridSize); glTexCoord2f(gridSize * 10 * tileSize, 0); glVertex3f(gridSize, ceilingHeight, -gridSize); glTexCoord2f(gridSize * 10 * tileSize, gridSize * 10 * tileSize); glVertex3f(gridSize, ceilingHeight, gridSize); glTexCoord2f(0, gridSize * 10 * tileSize); glVertex3f(-gridSize, ceilingHeight, gridSize); glEnd(); glEndList(); int wallDisplayList = glGenLists(1); glNewList(wallDisplayList, GL_COMPILE); glBegin(GL_QUADS); // North wall glTexCoord2f(0, 0); glVertex3f(-gridSize, floorHeight, -gridSize); glTexCoord2f(0, gridSize * 10 * tileSize); glVertex3f(gridSize, floorHeight, -gridSize); glTexCoord2f(gridSize * 10 * tileSize, gridSize * 10 * tileSize); glVertex3f(gridSize, ceilingHeight, -gridSize); glTexCoord2f(gridSize * 10 * tileSize, 0); glVertex3f(-gridSize, ceilingHeight, -gridSize); // West wall glTexCoord2f(0, 0); glVertex3f(-gridSize, floorHeight, -gridSize); glTexCoord2f(gridSize * 10 * tileSize, 0); glVertex3f(-gridSize, ceilingHeight, -gridSize); glTexCoord2f(gridSize * 10 * tileSize, gridSize * 10 * tileSize); glVertex3f(-gridSize, ceilingHeight, +gridSize); glTexCoord2f(0, gridSize * 10 * tileSize); glVertex3f(-gridSize, floorHeight, +gridSize); // East wall glTexCoord2f(0, 0); glVertex3f(+gridSize, floorHeight, -gridSize); glTexCoord2f(gridSize * 10 * tileSize, 0); glVertex3f(+gridSize, floorHeight, +gridSize); glTexCoord2f(gridSize * 10 * tileSize, gridSize * 10 * tileSize); glVertex3f(+gridSize, ceilingHeight, +gridSize); glTexCoord2f(0, gridSize * 10 * tileSize); glVertex3f(+gridSize, ceilingHeight, -gridSize); // South wall glTexCoord2f(0, 0); glVertex3f(-gridSize, floorHeight, +gridSize); glTexCoord2f(gridSize * 10 * tileSize, 0); glVertex3f(-gridSize, ceilingHeight, +gridSize); glTexCoord2f(gridSize * 10 * tileSize, gridSize * 10 * tileSize); glVertex3f(+gridSize, ceilingHeight, +gridSize); glTexCoord2f(0, gridSize * 10 * tileSize); glVertex3f(+gridSize, floorHeight, +gridSize); glEnd(); glEndList(); int floorDisplayList = glGenLists(1); glNewList(floorDisplayList, GL_COMPILE); glBegin(GL_QUADS); glTexCoord2f(0, 0); glVertex3f(-gridSize, floorHeight, -gridSize); glTexCoord2f(0, gridSize * 10 * tileSize); glVertex3f(-gridSize, floorHeight, gridSize); glTexCoord2f(gridSize * 10 * tileSize, gridSize * 10 * tileSize); glVertex3f(gridSize, floorHeight, gridSize); glTexCoord2f(gridSize * 10 * tileSize, 0); glVertex3f(gridSize, floorHeight, -gridSize); glEnd(); glEndList();

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  • port opengl2.x to opengl 3.x

    - by user46759
    I'm trying to port opencloth example to OpenGL 3.x. I've mostly done it to the shaders but I'm not sure of this part : glEnableClientState(GL_VERTEX_ARRAY); glBindBuffer(GL_ARRAY_BUFFER, vboID); glVertexPointer(4, GL_FLOAT, 0,0); glEnableClientState(GL_TEXTURE_COORD_ARRAY); glBindBuffer(GL_ARRAY_BUFFER, vboTexID); glTexCoordPointer(2, GL_FLOAT,0, 0); glEnableClientState(GL_NORMAL_ARRAY); glBindBuffer(GL_ARRAY_BUFFER, vboNormID); glNormalPointer(GL_FLOAT,sizeof(float)*4, 0); maybe glEnableVertexAttriArray somewhere ? any clue ? thanx edit : maybe something like that ? glEnableVertexAttribArray (2) ; // Ou glEnableVertexAttribArray (positionIndex) ; glBindBuffer(GL_ARRAY_BUFFER, vboTexID); glVertexAttribPointer (2, 2, GL_FLOAT, GL_FALSE, 0, 0) ; glEnableVertexAttribArray (3) ; // Ou glEnableVertexAttribArray (positionIndex) ; glBindBuffer(GL_ARRAY_BUFFER, vboNormID); glVertexAttribPointer (3, 4, GL_FLOAT, GL_FALSE, sizeof (float) * 4, 0) ;

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  • Low CPU/Memory/Memory-bandwith Pathfinding (maybe like in Warcraft 1)

    - by Valmond
    Dijkstra and A* are all nice and popular but what kind of algorithm was used in Warcraft 1 for pathfinding? I remember that the enemy could get trapped in bowl-like caverns which means there were (most probably) no full-path calculations from "start to end". If I recall correctly, the algorithm could be something like this: A) Move towards enemy until success or hitting a wall B) If blocked by a wall, follow the wall until you can move towards the enemy without being blocked and then do A) But I'd like to know, if someone knows :-) [edit] As explained to Byte56, I'm searching for a low cpu/mem/mem-bandwidth algo and wanted to know if Warcraft had some special secrets to deliver (never seen that kind of pathfinding elsewhere), I hope that that is more concordant with the stackexchange rules.

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  • In 3D camera math, calculate what Z depth is pixel unity for a given FOV

    - by badweasel
    I am working in iOS and OpenGL ES 2.0. Through trial and error I've figured out a frustum to where at a specific z depth pixels drawn are 1 to 1 with my source textures. So 1 pixel in my texture is 1 pixel on the screen. For 2d games this is good. Of course it means that I also factor in things like the size of the quad and the size of the texture. For example if my sprite is a quad 32x32 pixels. The quad size is 3.2 units wide and tall. And the texcoords are 32 / the size of the texture wide and tall. Then the frustum is: matrixFrustum(-(float)backingWidth/frustumScale,(float)backingWidth/frustumScale, -(float)backingHeight/frustumScale, (float)backingHeight/frustumScale, 40, 1000, mProjection); Where frustumScale is 800 for a retina screen. Then at a distance of 800 from camera the sprite is pixel for pixel the same as photoshop. For 3d games sometimes I still want to be able to do this. But depending on the scene I sometimes need the FOV to be different things. I'm looking for a way to figure out what Z depth will achieve this same pixel unity for a given FOV. For this my mProjection is set using: matrixPerspective(cameraFOV, near, far, (float)backingWidth / (float)backingHeight, mProjection); With testing I found that at an FOV of 45.0 a Z of 38.5 is very close to pixel unity. And at an FOV of 30.0 a Z of 59.5 is about right. But how can I calculate a value that is spot on? Here's my matrixPerspecitve code: void matrixPerspective(float angle, float near, float far, float aspect, mat4 m) { //float size = near * tanf(angle / 360.0 * M_PI); float size = near * tanf(degreesToRadians(angle) / 2.0); float left = -size, right = size, bottom = -size / aspect, top = size / aspect; // Unused values in perspective formula. m[1] = m[2] = m[3] = m[4] = 0; m[6] = m[7] = m[12] = m[13] = m[15] = 0; // Perspective formula. m[0] = 2 * near / (right - left); m[5] = 2 * near / (top - bottom); m[8] = (right + left) / (right - left); m[9] = (top + bottom) / (top - bottom); m[10] = -(far + near) / (far - near); m[11] = -1; m[14] = -(2 * far * near) / (far - near); } And my mView is set using: lookAtMatrix(cameraPos, camLookAt, camUpVector, mView); * UPDATE * I'm going to leave this here in case anyone has a different solution, can explain how they do it, or why this works. This is what I figured out. In my system I use a 10th scale unit to pixels on non-retina displays and a 20th scale on retina displays. The iPhone is 640 pixels wide on retina and 320 pixels wide on non-retina (obsolete). So if I want something to be the full screen width I divide by 20 to get the OpenGL unit width. Then divide that by 2 to get the left and right unit position. Something 32 units wide centered on the screen goes from -16 to +16. Believe it or not I have an excel spreadsheet do all this math for me and output all the vertex data for my sprite sheet. It's an arbitrary thing I made up to do .1 units = 1 non-retina pixel or 2 retina pixels. I could have made it .01 units = 2 pixels and someday I might switch to that. But for now it's the other. So the width of the screen in units is 32.0, and that means the left most pixel is at -16.0 and the right most is at 16.0. After messing a bit I figured out that if I take the [0] value of an identity modelViewProjection matrix and multiply it by 16 I get the depth required to get 1:1 pixels. I don't know why. I don't know if the 16 is related to the screen size or just a lucky guess. But I did a test where I placed a sprite at that calculated depth and varied the FOV through all the valid values and the object stays steady on screen with 1:1 pixels. So now I'm just calculating the unityDepth that way. If someone gives me a better answer I'll checkmark it.

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  • Implementing Camera Zoom in a 2D Engine

    - by Luke
    I'm currently trying to implement camera scaling/zoom in my 2D Engine. Normally I calculate the Sprite's drawing size and position similar to this pseudo code: render() { var x = sprite.x; var y = sprite.y; var sizeX = sprite.width * sprite.scaleX; // width of the sprite on the screen var sizeY = sprite.height * sprite.scaleY; // height of the sprite on the screen } To implement the scaling i changed the code to this: class Camera { var scaleX; var scaleY; var zoom; var finalScaleX; // = scaleX * zoom var finalScaleY; // = scaleY * zoom } render() { var x = sprite.x * Camera.finalScaleX; var y = sprite.y * Camera.finalScaleY; var sizeX = sprite.width * sprite.scaleX * Camera.finalScaleX; var sizeY = sprite.height * sprite.scaleY * Camera.finalScaleY; } The problem is that when the zoom is smaller than 1.0 all sprites are moved toward the top-left corner of the screen. This is expected when looking at the code but i want the camera to zoom on the center of the screen. Any tips on how to do that are welcome. :)

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  • GLSL per pixel lighting with custom light type

    - by Justin
    Ok, I am having a big problem here. I just got into GLSL yesterday, so the code will be terrible, I'm sure. Basically, I am attempting to make a light that can be passed into the fragment shader (for learning purposes). I have four input values: one for the position of the light, one for the color, one for the distance it can travel, and one for the intensity. I want to find the distance between the light and the fragment, then calculate the color from there. The code I have gives me a simply gorgeous ring of light that get's twisted and widened as the matrix is modified. I love the results, but it is not even close to what I am after. I want the light to be moved with all of the vertices, so it is always in the same place in relation to the objects. I can easily take it from there, but getting that to work seems to be impossible with my current structure. Can somebody give me a few pointers (pun not intended)? Vertex shader: attribute vec4 position; attribute vec4 color; attribute vec2 textureCoordinates; varying vec4 colorVarying; varying vec2 texturePosition; varying vec4 fposition; varying vec4 lightPosition; varying float lightDistance; varying float lightIntensity; varying vec4 lightColor; void main() { vec4 ECposition = gl_ModelViewMatrix * gl_Vertex; vec3 tnorm = normalize(vec3 (gl_NormalMatrix * gl_Normal)); fposition = ftransform(); gl_Position = fposition; gl_TexCoord[0] = gl_MultiTexCoord0; fposition = ECposition; lightPosition = vec4(0.0, 0.0, 5.0, 0.0) * gl_ModelViewMatrix * gl_Vertex; lightDistance = 5.0; lightIntensity = 1.0; lightColor = vec4(0.2, 0.2, 0.2, 1.0); } Fragment shader: varying vec4 colorVarying; varying vec2 texturePosition; varying vec4 fposition; varying vec4 lightPosition; varying float lightDistance; varying float lightIntensity; varying vec4 lightColor; uniform sampler2D texture; void main() { float l_distance = sqrt((gl_FragCoord.x * lightPosition.x) + (gl_FragCoord.y * lightPosition.y) + (gl_FragCoord.z * lightPosition.z)); float l_value = lightIntensity / (l_distance / lightDistance); vec4 l_color = vec4(l_value * lightColor.r, l_value * lightColor.g, l_value * lightColor.b, l_value * lightColor.a); vec4 color; color = texture2D(texture, gl_TexCoord[0].st); gl_FragColor = l_color * color; //gl_FragColor = fposition; }

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