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  • Standardizing camera input in OpenCV? (Contrast/Saturation/Brightness etc..)

    - by karpathy
    I am building an application using OpenCV that uses the webcam and runs some vision algorithms. I would like to make this application available on the internet after I am done, but I am concerned about the vast differences in camera settings on every computer, and I am worried that the algorithm may break if the settings are too different from mine. Is there any way, after capturing the frame, to post process it and make sure that the contrast is X, brightness is Y, and saturation is Z? I think the Camera settings themselves can not be changed from code directly using the current OpenCV Python bindings. Would anyone be able to tell me about how I could calculate some of these parameters from the image and adjust them appropriately using OpenCV?

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  • Rendering skybox in first person shooter

    - by brainydexter
    I am trying to get a skybox rendered correctly in my first person shooter game. I have the skybox cube rendering using GL_TEXTURE_CUBE_MAP. I author the cube with extents of -1 and 1 along X,Y and Z. However, I can't wrap my head around the camera transformations that I need to apply to get it right. My render loop looks something like this: mp_Camera-ApplyTransform() :: Takes the current player transformation and inverts it and pushes that on the modelview stack. Draw GameObjects Draw Skybox DrawSkybox does the following: glEnable(GL_TEXTURE_CUBE_MAP); glDepthMask(GL_FALSE); // draw the cube here with extents glDisable(GL_TEXTURE_CUBE_MAP); glDepthMask(GL_TRUE); Do I need to translate the skybox by the translation of the camera ? (btw, that didn't help either) EDIT: I forgot to mention: It looks like a small cube with unit extents. Also, I can strafe in/out of the cube. Screenshot:

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  • using isight camera in macbookpro(8,2) on ubuntu 12.04 virtualbox VM

    - by Kurt Spindler
    I'm having a lot of trouble using the built-in isight camera on my macbookpro8,2 (early 2011) from an ubuntu 12.04 virtual machine, run inside VirtualBox. The following is the log I get when I try to run guvcview ubuntu@ubuntu:~$ guvcview guvcview 1.5.3 ALSA lib pcm.c:2217:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.rear ALSA lib pcm.c:2217:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.center_lfe ALSA lib pcm.c:2217:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.side ALSA lib pcm.c:2217:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.surround71 ALSA lib setup.c:565:(add_elem) Cannot obtain info for CTL elem (MIXER,'IEC958 Playback Default',0,0,0): No such file or directory ALSA lib setup.c:565:(add_elem) Cannot obtain info for CTL elem (MIXER,'IEC958 Playback Default',0,0,0): No such file or directory ALSA lib setup.c:565:(add_elem) Cannot obtain info for CTL elem (MIXER,'IEC958 Playback Default',0,0,0): No such file or directory ALSA lib pcm.c:2217:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.hdmi ALSA lib pcm.c:2217:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.hdmi ALSA lib pcm.c:2217:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.modem ALSA lib pcm.c:2217:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.modem ALSA lib pcm.c:2217:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.phoneline ALSA lib pcm.c:2217:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.phoneline ALSA lib audio/pcm_bluetooth.c:1614:(audioservice_expect) BT_GET_CAPABILITIES failed : Input/output error(5) ALSA lib audio/pcm_bluetooth.c:1614:(audioservice_expect) BT_GET_CAPABILITIES failed : Input/output error(5) ALSA lib audio/pcm_bluetooth.c:1614:(audioservice_expect) BT_GET_CAPABILITIES failed : Input/output error(5) ALSA lib audio/pcm_bluetooth.c:1614:(audioservice_expect) BT_GET_CAPABILITIES failed : Input/output error(5) ALSA lib pcm_dmix.c:957:(snd_pcm_dmix_open) The dmix plugin supports only playback stream Cannot connect to server socket err = No such file or directory Cannot connect to server socket jack server is not running or cannot be started video device: /dev/video0 Init. FaceTime HD Camera (Built-in) (location: usb-0000:00:0b.0-1) { pixelformat = 'YUYV', description = 'YUV 4:2:2 (YUYV)' } { discrete: width = 160, height = 120 } Time interval between frame: 100/2997, 1/25, 1/24, 1/15, { discrete: width = 176, height = 144 } Time interval between frame: 100/2997, 1/25, 1/24, 1/15, { discrete: width = 320, height = 240 } Time interval between frame: 100/2997, 1/25, 1/24, 1/15, { discrete: width = 352, height = 288 } Time interval between frame: 100/2997, 1/25, 1/24, 1/15, { discrete: width = 640, height = 480 } Time interval between frame: 100/2997, 1/25, 1/24, 1/15, { discrete: width = 1280, height = 720 } Time interval between frame: 1/10, { pixelformat = 'MJPG', description = 'MJPEG' } { discrete: width = 960, height = 540 } Time interval between frame: 100/2997, 1/25, 1/24, 1/15, { discrete: width = 1024, height = 576 } Time interval between frame: 100/2997, 1/25, 1/24, 1/15, { discrete: width = 1280, height = 720 } Time interval between frame: 100/2997, 1/25, 1/24, 1/15, { pixelformat = 'RGB3', description = 'RGB3' } { discrete: width = 160, height = 120 } Time interval between frame: 100/2997, 1/25, 1/24, 1/15, { discrete: width = 176, height = 144 } Time interval between frame: 100/2997, 1/25, 1/24, 1/15, { discrete: width = 320, height = 240 } Time interval between frame: 100/2997, 1/25, 1/24, 1/15, { discrete: width = 352, height = 288 } Time interval between frame: 100/2997, 1/25, 1/24, 1/15, { discrete: width = 640, height = 480 } Time interval between frame: 100/2997, 1/25, 1/24, 1/15, { discrete: width = 1280, height = 720 } Time interval between frame: 100/2997, 1/25, 1/24, 1/15, { discrete: width = 960, height = 540 } Time interval between frame: 100/2997, 1/25, 1/24, 1/15, { discrete: width = 1024, height = 576 } Time interval between frame: 100/2997, 1/25, 1/24, 1/15, { pixelformat = 'BGR3', description = 'BGR3' } { discrete: width = 160, height = 120 } Time interval between frame: 100/2997, 1/25, 1/24, 1/15, { discrete: width = 176, height = 144 } Time interval between frame: 100/2997, 1/25, 1/24, 1/15, { discrete: width = 320, height = 240 } Time interval between frame: 100/2997, 1/25, 1/24, 1/15, { discrete: width = 352, height = 288 } Time interval between frame: 100/2997, 1/25, 1/24, 1/15, { discrete: width = 640, height = 480 } Time interval between frame: 100/2997, 1/25, 1/24, 1/15, { discrete: width = 1280, height = 720 } Time interval between frame: 100/2997, 1/25, 1/24, 1/15, { discrete: width = 960, height = 540 } Time interval between frame: 100/2997, 1/25, 1/24, 1/15, { discrete: width = 1024, height = 576 } Time interval between frame: 100/2997, 1/25, 1/24, 1/15, { pixelformat = 'YU12', description = 'YU12' } { discrete: width = 160, height = 120 } Time interval between frame: 100/2997, 1/25, 1/24, 1/15, { discrete: width = 176, height = 144 } Time interval between frame: 100/2997, 1/25, 1/24, 1/15, { discrete: width = 320, height = 240 } Time interval between frame: 100/2997, 1/25, 1/24, 1/15, { discrete: width = 352, height = 288 } Time interval between frame: 100/2997, 1/25, 1/24, 1/15, { discrete: width = 640, height = 480 } Time interval between frame: 100/2997, 1/25, 1/24, 1/15, { discrete: width = 1280, height = 720 } Time interval between frame: 100/2997, 1/25, 1/24, 1/15, { discrete: width = 960, height = 540 } Time interval between frame: 100/2997, 1/25, 1/24, 1/15, { discrete: width = 1024, height = 576 } Time interval between frame: 100/2997, 1/25, 1/24, 1/15, { pixelformat = 'YV12', description = 'YV12' } { discrete: width = 160, height = 120 } Time interval between frame: 100/2997, 1/25, 1/24, 1/15, { discrete: width = 176, height = 144 } Time interval between frame: 100/2997, 1/25, 1/24, 1/15, { discrete: width = 320, height = 240 } Time interval between frame: 100/2997, 1/25, 1/24, 1/15, { discrete: width = 352, height = 288 } Time interval between frame: 100/2997, 1/25, 1/24, 1/15, { discrete: width = 640, height = 480 } Time interval between frame: 100/2997, 1/25, 1/24, 1/15, { discrete: width = 1280, height = 720 } Time interval between frame: 100/2997, 1/25, 1/24, 1/15, { discrete: width = 960, height = 540 } Time interval between frame: 100/2997, 1/25, 1/24, 1/15, { discrete: width = 1024, height = 576 } Time interval between frame: 100/2997, 1/25, 1/24, 1/15, vid:05ac pid:8509 driver:uvcvideo checking format: 1196444237 VIDIOC_G_COMP:: Invalid argument compression control not supported fps is set to 1/25 drawing controls no codec detected for H264 no codec detected for MP3 - (lavc) Checking video mode 960x540@32bpp : OK Could not grab image (select timeout): Resource temporarily unavailable Could not grab image (select timeout): Resource temporarily unavailable Could not grab image (select timeout): Resource temporarily unavailable Could not grab image (select timeout): Resource temporarily unavailable Could not grab image (select timeout): Resource temporarily unavailable Could not grab image (select timeout): Resource temporarily unavailable Could not grab image (select timeout): Resource temporarily unavailable Could not grab image (select timeout): Resource temporarily unavailable Could not grab image (select timeout): Resource temporarily unavailable write /home/ubuntu/.guvcviewrc OK free controls cleaned allocations - 100% Closing portaudio ...OK Closing GTK... OK ubuntu@ubuntu:~$ Any help would be greatly appreciated. Only clue I have is that I initially was having problems, tried using the old method of fixing isights (involving installing isight-firmware-tools) before realizing that I just hadn't turned on the VM setting to allow the VM to access the webcam. :) Anyway, I wonder if installing that messed something up. However, I think this is a red herring because I've: shut down and turned back on the Mac, restarted the VM, tried a different VM (for which I never installed isight-firmware-tools, and created an entirely new ubuntu vm. All instances have had this problem. Similarly, other viewers, such as cheese, avplay, avconv have had all various kinds of errors.

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  • Making a Background Scrolling in Stacking Game

    - by David Dimalanta
    Hmmm...Is it a good idea to use a LibGDX parallax background for making a stacking game (i.e. PAPA STACKer Lite)? For example, I'm starting to use the blocks to drag-n-drop it. Next, when the next piece reaches the top of the screen, it automatically scrolls to the next one where the available space left. Aside from that, is it also involved with the camera code (Orthographic Camera) that the screen size appeared like 720x1280 but actually it's 1440x2560 for example? And another thing, does the background scrolling have the option to scroll from start to finish and infinite?

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  • fragment shader directional light positioning with camera

    - by meWantToLearn
    Im trying to set up directional lighting in the fragment shader. So the direction of my light moves with the camera position. #version 150 core uniform sampler2D diffuseTex; uniform vec4 lightColour; uniform vec3 lightDirection; vec3 LNorm = normalize(lightDirection); vec3 normal = normalize(IN.normal); vec3 calColour = lightColour[i].rgb * intensity; gl_FragColor = vec4(diffuse.rbg * calColour, diffuse.a); It lights the entire scene.

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  • Ubuntu - Psychonauts - Camera involentarily listing to the right

    - by James
    I've recently purchased the Humble Bundle V and have been having an absolute riot with the games given. The one problem I'm running into though, is that whenever I launch Psychonauts and run a game, the Camera lists to the right slowly and I can't get it to stop. Strangely enough when I zoom in (with z), it lists to the left. I was wondering if anyone else had this problem and if there was a solution. Maybe it's even the mouse configs I currently have on the laptop that interacts strangely with 3D environments.

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  • Take Camera Phone Macro Photos with a Cheap Laser Pointer Lens

    - by Jason Fitzpatrick
    Inside those cheap laser pointers you see in the grocery store checkout line there’s a handy little plastic lens that, when slapped on your phone’s camera, makes it easy to take macro photographs. In this tutorial, they take the lens from a laser point and secure it using tape and a bobby pin. An alternative method to achieve the same end (and with a higher quality lens) is to dismantle a CD/DVD drive to source the lens and use painter’s tape to hold the lens in place–this is the technique I used several years ago, check out the tutorial video here. Laser Pointer Macro Lens [via Apartment Therapy] How to Get Pro Features in Windows Home Versions with Third Party Tools HTG Explains: Is ReadyBoost Worth Using? HTG Explains: What The Windows Event Viewer Is and How You Can Use It

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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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  • Provide A Scrolling "Camera" View Over A 2D Game Map

    - by BitCrash
    I'm in the process of attempting to create a 2D MMO type game with Kryonet and some basic sprites, mostly for my own learning. I have the back end set up great (By my standards) and I'm moving on to actually getting some things drawn onto the map. I cannot for the life of me figure out a solid way to have a "Camera" follow a player around a large area. The view pane for the game is 640 x 480 pixels, and each tile is 32x32 pixels (Thats 20 tiles wide and 15 high for the viewpane) I have tried a couple things to do this, but they did not seem to work out so well. I had a JScrollPane with 9 "Viewpane"-sized canvases in it, and tried to have the JScrollPane move in accordance with the player. The issue came when I reached the end of the JScrollPane. I tried to "Flip" canvases, sending the canvas currrently drawing the player to the middle of the 9 and load the corresponding maps onto the other ones. It was slow and worked poorly. I'm looking for any advice or previous experience with this; any ideas? Thank you! Edit and Clarification: I did not mean to mention Kryonet, I was merely providing peripheral information in case there was something that would help which I could not foresee. Instead of having an array of 9 canvases, why not just have one large canvas loading a large map every once in a while? I'm willing to have "load times" where as with the canvas array I would have none (in theory) to give the user a smooth experience. I could just change the size and location of the map with a modified setBounds() call on the canvas in a layered pane (layered because I have hidden swing items, like inventories and stuff) I'll try it out and post here how it goes for people asking the same question.

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  • Refresh displayed Camera Roll contents

    - by zoul
    Hello! I use the UIImagePickerController class to display the Camera Roll contents. I have a second thread that saves an image to the Camera Roll. When the images has finished saving, it does not appear in the Camera Roll that’s open. Is there a way to force the Camera Roll to refresh? (Other than dismissing and displaying it again.)

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  • Fiber-Optic Cable Trick Brings Remote Triggering to Older Flashes

    - by Jason Fitzpatrick
    Many older flashes lack for a jack to input a sync cable and rely exclusively on a simple slave mode triggered by the primary flash. This hack uses a piece of scrap fiber optic cable to trigger the flash in bright conditions. Using a flash as an optical slave indoors isn’t much of a problem, but if you introduce bright light (such as outdoor lighting conditions), the ambient light can overpower the small on-camera flash and render the optical slave function useless. To overcome this, Marcell over at Fiber Strobe (a blog dedicated to cataloging experiments in incorporating fiber optics into photography) came up with a simple work around. By using some foam crafting materials and tape, he whipped up a simple mount for a strand of scrap fiber optic cable to connect between the on-camera flash and the sensor on the slave flash. Once attached it works exactly like as sync cable would, except it’s transmitting a pulse of light instead of a pulse of electricity. Hit up the link below for more pictures and a build guide. DIY Fiber Sync Cord [via DIY Photography] HTG Explains: What Is Windows RT and What Does It Mean To Me? HTG Explains: How Windows 8′s Secure Boot Feature Works & What It Means for Linux Hack Your Kindle for Easy Font Customization

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  • Rotate a vector

    - by marc wellman
    I want my first-person camera to smoothly change its viewing direction from direction d1 to direction d2. The latter direction is indicated by a target position t2. So far I have implemented a rotation that works fine but the speed of the rotation slows down the closer the current direction gets to the desired one. This is what I want to avoid. Here are the two very simple methods I have written so far: // this method initiates the direction change and sets the parameter public void LookAt(Vector3 target) { _desiredDirection = target - _cameraPosition; _desiredDirection.Normalize(); _rotation = new Matrix(); _rotationAxis = Vector3.Cross(Direction, _desiredDirection); _isLooking = true; } // this method gets execute by the Update()-method if _isLooking flag is up. private void _lookingAt() { dist = Vector3.Distance(Direction, _desiredDirection); // check whether the current direction has reached the desired one. if (dist >= 0.00001f) { _rotationAxis = Vector3.Cross(Direction, _desiredDirection); _rotation = Matrix.CreateFromAxisAngle(_rotationAxis, MathHelper.ToRadians(1)); Direction = Vector3.TransformNormal(Direction, _rotation); } else { _onDirectionReached(); _isLooking = false; } } Again, rotation works fine; camera reaches its desired direction. But the speed is not equal over the course of movement - it slows down. How to achieve a rotation with constant speed ?

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  • Drawing two orthogonal strings in 3d space in Android Canvas?

    - by hasanghaforian
    I want to draw two strings in canvas.First string must be rotated around Y axis,for example 45 degrees.Second string must be start at the end of first string and also it must be orthogonal to first string. This is my code: String text = "In the"; float textWidth = redPaint.measureText(text); Matrix m0 = new Matrix(); Matrix m1 = new Matrix(); Matrix m2 = new Matrix(); mCamera = new Camera(); canvas.setMatrix(null); canvas.save(); mCamera.rotateY(45); mCamera.getMatrix(m0); m0.preTranslate(-100, -100); m0.postTranslate(100, 100); canvas.setMatrix(m0); canvas.drawText(text, 100, 100, redPaint); mCamera = new Camera(); mCamera.rotateY(90); mCamera.getMatrix(m1); m1.preTranslate(-textWidth - 100, -100); m1.postTranslate(textWidth + 100, 100); m2.setConcat(m1, m0); canvas.setMatrix(m2); canvas.drawText(text, 100 + textWidth, 100, greenPaint); But in result,only first string(text with red font)is visible. How can I do drawing two orthogonal strings in 3d space?

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  • How do I properly implement zooming in my game?

    - by Rudy_TM
    I'm trying to implement a zoom feature but I have a problem. I am zooming in and out a camera with a pinch gesture, I update the camera each time in the render, but my sprites keep their original position and don't change with the zoom in or zoom out. The Libraries are from libgdx. What am I missing? private void zoomIn() { ((OrthographicCamera)this.stage.getCamera()).zoom += .01; } public boolean pinch(Vector2 arg0, Vector2 arg1, Vector2 arg2, Vector2 arg3) { // TODO Auto-generated method stub zoomIn(); return false; } public void render(float arg0) { this.gl.glClear(GL10.GL_DEPTH_BUFFER_BIT | GL10.GL_COLOR_BUFFER_BIT); ((OrthographicCamera)this.stage.getCamera()).update(); this.stage.draw(); } public boolean touchDown(int arg0, int arg1, int arg2) { this.stage.toStageCoordinates(arg0, arg1, point); Actor actor = this.stage.hit(point.x, point.y); if(actor instanceof Group) { ((LevelSelect)((Group) actor).getActors().get(0)).touched(); } return true; } Zoom In Zoom Out

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  • Why is the camera not following the player? [on hold]

    - by Homer_Simpson
    I use the following code to create Parallax Scrolling: http://www.david-gouveia.com/portfolio/2d-camera-with-parallax-scrolling-in-xna/ Parallax Scrolling is working but I don't know how to focus the camera on the player. If the player moves, then the camera doesn't follow the player. The player leaves the screen when I'm moving it. I use the following code(as described in the tutorial), but it's not working: // Updates my camera to lock on the character _camera.LookAt(player.Playerposition); What can I do so that the player is always in the center of the screen/camera? My player class: public class Player { Texture2D Playertex; public Vector2 Playerposition = new Vector2(400, 240); private Game1 game1; public Player(Game1 game) { game1 = game; } public void Load(ContentManager content) { Playertex = content.Load<Texture2D>("8bitmario"); TouchPanel.EnabledGestures = GestureType.HorizontalDrag; } public void Update(GameTime gameTime) { while (TouchPanel.IsGestureAvailable) { GestureSample gs = TouchPanel.ReadGesture(); switch (gs.GestureType) { case GestureType.HorizontalDrag: Playerposition.X += 3f; break; } } } public void Render(SpriteBatch batch) { batch.Draw(Playertex, new Vector2(Playerposition.X - Playertex.Width / 2, Playerposition.Y - Playertex.Height / 2), Color.White); } } In Game1, I update the player and camera class: protected override void Update(GameTime gameTime) { // Updates my character's position player.Update(gameTime); // Updates my camera to lock on the character _camera.LookAt(player.Playerposition); base.Update(gameTime); } protected override void Draw(GameTime gameTime) { GraphicsDevice.Clear(Color.CornflowerBlue); foreach (Layer layer in _layers) layer.Draw(spriteBatch); spriteBatch.Begin(SpriteSortMode.Deferred, null, null, null, null, null, _camera.GetViewMatrix(new Vector2(0.0f, 0.0f))); player.Render(spriteBatch); spriteBatch.End(); base.Draw(gameTime); }

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  • how can stop creating duplicates in camera roll while using UISaveVideoAtPathToSavedPhotosAlbum to s

    - by srikanth rongali
    I have a video in applications documents folder. I need it to be saved in camera roll. So, I used UISaveVideoAtPathToSavedPhotosAlbum method to save it in camera roll. It's working and I can see the video added to camera roll. But, the problem is every time I execute the application with same video(with same file name), it is added another time in camera roll instead of replacing the old one. So, it is creating the duplicates of the video. How can I make the application work like if a video is present in camera roll and again added with same file name, then old one is replaced by new video.

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  • Detect if camera is capturing in Flash

    - by Ben
    I'm having trouble with Camera.getCamera() in Flash AS3. If there are multiple camera drivers, it does not necessarily pick the correct one. If the default is the correct, the program works fine; however, if another driver is selected as the default then LED on the webcam does not come on and no video is captured. I can cycle through the available cams and select an arbitrary one. I don't, however, know how to determine if the selected camera is correct. It is not returning null. I considered using camera.currentFPS, but it's not clear when this gets updated. I'm really struggling to determine dynamically which camera will do the trick!

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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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