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Remove a Digital Camera’s IR Filter for IR Photography on the Cheap

- by Jason Fitzpatrick

Whether you have a DSLR or a point-and-shoot, this simple hack allows you to shoot awesome IR photographs without the expense of a high-quality IR filter (or the accompanying loss of light that comes with using it). How does it work? You’ll need to take apart your camera and remove a single fragile layer of IR blocking glass from the CCD inside the camera body. After doing so, you’ll have a camera that sees infrared light by default, no special add-on filters necessary. Because it sees the IR light without the filters you’ll also skip out on the light loss that occurs with the addition of the add-on IR filter. The downside? You’re altering the camera in permanent and warranty-voiding way. This is most definitely not a hack for your brand new $2,000 DSLR, but it is a really fun hack to try out on an old point and shoot camera or your circa-2004 depreciated DSLR. Hit up the link below to see the process performed on an old Canon point and shoot–we’d strongly recommend searching for a break down guide for your specific camera model before attempting the trick on your own gear. Are You Brave Enough to IR-ize Your Camera [DIY Photography] HTG Explains: How Windows Uses The Task Scheduler for System Tasks HTG Explains: Why Do Hard Drives Show the Wrong Capacity in Windows? Java is Insecure and Awful, It’s Time to Disable It, and Here’s How

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Strange if-else branching behavior in a fragment shader

- by Winged

In my fragment shader I have passed an uniform int uLightType variable, which indicates what type of light is in usage right now. The problem is that if-else branching does not work correctly - the fragment shader performs instructions in every if statement block. if (uLightType == 1) { // Spotlight light type vec3 depthTextureCoord = vDepthPosition.xyz / vDepthPosition.w; shadowDepth = unpack(texture2D(uDepthMapSampler, depthTextureCoord.xy)); } else if (uLightType == 2) { // Omni-directional light type shadowDepth = unpack(textureCube(uDepthCubemapSampler, -lightVec)); } In the case when uLightType equals 1, unless I comment out the content of the second if block, it assigns an another value to shadowDepth. Also while uLightType equals 1, when I remove the second 'if' block and change == to != like in the sample code below, nothing happens (which means that uLightType really equals 1). if (uLightType != 1) { // Spotlight light type vec3 depthTextureCoord = vDepthPosition.xyz / vDepthPosition.w; shadowDepth = unpack(texture2D(uDepthMapSampler, depthTextureCoord.xy)); } Also, when I manually create an int variable (which is not an uniform) like this: var lightType = 1; and replace uLightType with it in the if-else branch, everything works fine, so I guess it have something to do with the fact that uLightType is the uniform.

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Simplest way to render image over top of another with another image used as mask in OpenGL?

- by Adam Naylor

The effect I'm looking for is to have a single large background image that is always visible (at full alpha) and then show a second image (what I call a light map or specular map) that is partially shown over the top based on a third image (which is effectively a mask). The effect is similar to this effect except instead of simply darkening or lightening the background image using the third image it needs to mask the second without effecting the first at all. The third image is the only one that moves therefore hard baking the third images alpha into the second image isn't an option. If my explanation isn't clear I'll provide visual examples when I have more time. I'd prefer not to go down a shader route as I haven't taught myself this area yet so unless I have too I'd rather try to achieve this with simple alpha blending. Happy to use a shader approach. Cheers. Additional These third images are obviously light sources being cast onto the first image showing the specular information from the second image to simulate the light 'shining' off the objects in the first image. The solution I implement will need to allow two light sources to potentially overlap so my current thoughts are that the alpha values of the two images will need to be combined (Added?) to produce a final image which masks the second image? Don't worry about things like coloured lights. For this technique the lights are all considered white.

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OpenGL lighting with dynamic geometry

- by Tank

I'm currently thinking hard about how to implement lighting in my game. The geometry is quite dynamic (fixed 3D grid with custom geometry in each cell) and needs some light to get more depth and in general look nicer. A scene in my game always contains sunlight and local light sources like lamps (point lights). One can move underground, so sunlight must be able to illuminate as far as it can get. Here's a render of a typical situation: The lamp is positioned behind the wall to the top, and in the hollow cube there's a hole in the back, so that light can shine through. (I don't want soft shadows, this is just for illustration) While spending the whole day searching through Google, I stumbled on some keywords like deferred rendering, forward rendering, ambient occlusion, screen space ambient occlusion etc. Some articles/tutorials even refer to "normal shading", but to be honest I don't really have an idea to even do simple shading. OpenGL of course has a fixed lighting pipeline with 8 possible light sources. However they just illuminate all vertices without checking for occluding geometry. I'd be very thankful if someone could give me some pointers into the right direction. I don't need complete solutions or similar, just good sources with information understandable for someone with nearly no lighting experience (preferably with OpenGL).

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Attaching a Command to the WP7 Application Bar.

- by mbcrump

One of the biggest problems that I’ve seen with people creating WP7 applications is how do you bind the application bar to a Relay Command. If your using MVVM then this is particular important. Let’s examine the code that one might add to start with. <phone:PhoneApplicationPage.ApplicationBar> <shell:ApplicationBar IsVisible="True" IsMenuEnabled="True"> <shell:ApplicationBarIconButton x:Name="appbar_button1" IconUri="/icons/appbar.questionmark.rest.png" Text="About"> <i:Interaction.Triggers> <i:EventTrigger EventName="Click"> <GalaSoft_MvvmLight_Command:EventToCommand Command="{Binding DisplayAbout, Mode=OneWay}" /> </i:EventTrigger> </i:Interaction.Triggers> </shell:ApplicationBarIconButton> <shell:ApplicationBar.MenuItems> <shell:ApplicationBarMenuItem x:Name="menuItem1" Text="MenuItem 1"></shell:ApplicationBarMenuItem> <shell:ApplicationBarMenuItem x:Name="menuItem2" Text="MenuItem 2"></shell:ApplicationBarMenuItem> </shell:ApplicationBar.MenuItems> </shell:ApplicationBar> </phone:PhoneApplicationPage.ApplicationBar> Everything looks right. But we quickly notice that we have a squiggly line under our Interaction.Triggers. The problem is that the object is not a FrameworkObject. This same code would have worked perfect if this were a normal button. OK. Point has been proved. Let’s make the ApplicationBar support Commands. So, go ahead and create a new project using MVVM Light. If you want to check out the source and work along side this tutorial then click here. 7 Easy Steps to have binding on the Application Bar using MVVM Light (I might add that you don’t have to use MVVM Light to get this functionality, I just prefer it.) 1) Download MVVM Light if you don’t already have it and install the project templates. It is available at http://mvvmlight.codeplex.com/. 2) Click File-New Project and navigate to Silverlight for Windows Phone. Make sure you use the MVVM Light (WP7) Template. 3) Now that we have our project setup and ready to go let’s download a wrapper created by Nicolas Humann here, it is called Phone7.Fx. After you download it then extract it somewhere that you can find it. This wrapper will make our application bar/menu item bindable. 4) Right click References inside your WP7 project and add the .dll file to your project. 5) In your MainPage.xaml you will need to add the proper namespace to it. Don’t forget to build your project afterwards. xmlns:Preview="clr-namespace:Phone7.Fx.Preview;assembly=Phone7.Fx.Preview" 6) Now you can add the BindableAppBar to your MainPage.xaml with a few lines of code. <Preview:BindableApplicationBar x:Name="AppBar" BarOpacity="1.0" > <Preview:BindableApplicationBarIconButton Command="{Binding DisplayAbout}" IconUri="/icons/appbar.questionmark.rest.png" Text="About" /> <Preview:BindableApplicationBar.MenuItems> <Preview:BindableApplicationBarMenuItem Text="Settings" Command="{Binding InputBox}" /> </Preview:BindableApplicationBar.MenuItems> </Preview:BindableApplicationBar> So your final MainPage.xaml will look similar to this: NOTE: The AppBar will be located inside of the Grid using this wrapper.  <Grid x:Name="LayoutRoot" Background="Transparent"> <Grid.RowDefinitions> <RowDefinition Height="Auto" /> <RowDefinition Height="*" /> </Grid.RowDefinitions>  <StackPanel x:Name="TitlePanel" Grid.Row="0" Margin="24,24,0,12"> <TextBlock x:Name="ApplicationTitle" Text="{Binding ApplicationTitle}" Style="{StaticResource PhoneTextNormalStyle}" /> <TextBlock x:Name="PageTitle" Text="{Binding PageName}" Margin="-3,-8,0,0" Style="{StaticResource PhoneTextTitle1Style}" /> </StackPanel>  <Grid x:Name="ContentGrid" Grid.Row="1"> <TextBlock Text="{Binding Welcome}" Style="{StaticResource PhoneTextNormalStyle}" HorizontalAlignment="Center" VerticalAlignment="Center" FontSize="40" /> </Grid> <Preview:BindableApplicationBar x:Name="AppBar" BarOpacity="1.0" > <Preview:BindableApplicationBarIconButton Command="{Binding DisplayAbout}" IconUri="/icons/appbar.questionmark.rest.png" Text="About" /> <Preview:BindableApplicationBar.MenuItems> <Preview:BindableApplicationBarMenuItem Text="Settings" Command="{Binding InputBox}" /> </Preview:BindableApplicationBar.MenuItems> </Preview:BindableApplicationBar> </Grid> 7) Let’s go ahead and create the RelayCommands and write them up to a MessageBox by editing our MainViewModel.cs file. public class MainViewModel : ViewModelBase { public string ApplicationTitle { get { return "MVVM LIGHT"; } } public string PageName { get { return "My page:"; } } public string Welcome { get { return "Welcome to MVVM Light"; } } public RelayCommand DisplayAbout { get; private set; } public RelayCommand InputBox { get; private set; } /// <summary> /// Initializes a new instance of the MainViewModel class. /// </summary> public MainViewModel() { if (IsInDesignMode) { // Code runs in Blend --> create design time data. } else { DisplayAbout = new RelayCommand(() => { MessageBox.Show("About box called!"); }); InputBox = new RelayCommand(() => { MessageBox.Show("settings button called"); }); } } If you run the project now you should get something similar to this (notice the AppBar at the bottom): Now if you hit the question mark then you will get the following MessageBox: The MenuItem works as well so for Settings: As you can see, its pretty easy to add a Command to the ApplicationBar/MenuItem. If you want to look through the full source code then click here. Subscribe to my feed

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#mvvmlight V4 for Windows 8 RP is available

- by Laurent Bugnion

I took a moment out of a very busy weekend to publish an update to MVVM Light for Windows 8 Release Preview. You can download the DLLs from the Codeplex site. Or, if you use Nuget, you can update the MVVM Light package, which will install the newest DLLs. For more information about Nuget, visit Nuget.org as well as the MVVM Light Nuget page. Note: I also took the occasion to fix an issue where the DLLs for the .NET 4 framework were not signed. The DLLs contained in this package are properly signed. As usual, feedback is very welcomed! Happy coding Laurent Laurent Bugnion (GalaSoft) Subscribe | Twitter | Facebook | Flickr | LinkedIn

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Cisco Linksys AE2500 wireless adapter not working

- by makuto

I have a Cisco AE2500 I've used with my laptop to get internet. I had to install the drivers by following this forum: http://ubuntuforums.org/showthread.php?t=1805830 But now the blue light on the adapter doesn't turn on at all, but ndiswrapper reports it is connected. I have no connection to the internet on my laptop, and the adapter doesn't show it's blue light on any of the USB ports of my computer or on the 4 port hub I have. Is there some way I can reset something so that the blue light will show again? I'm using Ubuntu 11.10 on a Dell Latitude D505 laptop. EDIT: I deleted and reinstalled the same exact driver and everything worked again.

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How is Basic Physics applied in CS/SE?

- by Wulf

What basic physics principles do software engineers and/or computer scientists use to help solve specific or common problems? The first one that came to my head was creating a Physics engine for a game; physics is involved, as it requires knowledge of: Forces and Motion: Kinematics, Dynamics, Circular Motion However, I need another example, but haven't come across one that involves basic physics. Please consider the following basic physics (grade 12 level) concepts: Energy and Momentum: Work and Energy, Momentum and Collisions, Gravitational and Celestial Mechanics Electric, Gravitational & Magnetic Field: Electric Charges and Electric Field, Magnetic Fields and Electomagnetism The Wave Nature of Light: Waves and Light, Wave Effects of Light Matter-Energy Interface: Einstein’s Special Theory of Relativity, Waves, Photons and Matter, Radioactivity and Elementary Particles I will be happy with any response; Keywords for google, names of methods like raycasting, etc.

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Mutating Programming Language?

- by MattiasK

For fun I was thinking about how one could build a programming language that differs from OOP and came up with this concept. I don't have a strong foundation in computer science so it might be common place without me knowing it (more likely it's just a stupid idea :) I apologize in advance for this somewhat rambling question :) Anyways here goes: In normal OOP methods and classes are variant only upon parameters, meaning if two different classes/methods call the same method they get the same output. My, perhaps crazy idea, is that the calling method and class could be an "invisible" part of it's signature and the response could vary depending on who call's an method. Say that we have a Window object with a Break() method, now anyone (who has access) could call this method on Window with the same result. Now say that we have two different objects, Hammer and SledgeHammer. If Break need to produce different results based on these we'd pass them as parameters Break(IBluntObject bluntObject) With a mutating programming language (mpl) the operating objects on the method would be visible to the Break Method without begin explicitly defined and it could adopt itself based on them). So if SledgeHammer calls Window.Break() it would generate vastly different results than if Hammer did so. If OOP classes are black boxes then MPL are black boxes that knows who's (trying) to push it's buttons and can adapt accordingly. You could also have different permission sets on methods depending who's calling them rather than having absolute permissions like public and private. Does this have any advantage over OOP? Or perhaps I should say, would it add anything to it since you should be able to simply add this aspect to methods (just give access to a CallingMethod and CallingClass variable in context) I'm not sure, might be to hard to wrap one's head around, it would be kinda interesting to have classes that adopted themselves to who uses them though. Still it's an interesting concept, what do you think, is it viable?

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How do I get FEATURE_LEVEL_9_3 to work with shaders in Direct3D11?

- by Dominic

Currently I'm going through some tutorials and learning DX11 on a DX10 machine (though I just ordered a new DX11 compatible computer) by means of setting the D3D_FEATURE_LEVEL_ setting to 10_0 and switching the vertex and pixel shader versions in D3DX11CompileFromFile to "vs_4_0" and "ps_4_0" respectively. This works fine as I'm not using any DX11-only features yet. I'd like to make it compatible with DX9.0c, which naively I thought I could do by changing the feature level setting to 9_3 or something and taking the vertex/pixel shader versions down to 3 or 2. However, no matter what I change the vertex/pixel shader versions to, it always fails when I try to call D3DX11CompileFromFile to compile the vertex/pixel shader files when I have D3D_FEATURE_LEVEL_9_3 enabled. Maybe this is due to the the vertex/pixel shader files themselves being incompatible for the lower vertex/pixel shader versions, but I'm not expert enough to say. My shader files are listed below: Vertex shader: cbuffer MatrixBuffer { matrix worldMatrix; matrix viewMatrix; matrix projectionMatrix; }; struct VertexInputType { float4 position : POSITION; float2 tex : TEXCOORD0; float3 normal : NORMAL; }; struct PixelInputType { float4 position : SV_POSITION; float2 tex : TEXCOORD0; float3 normal : NORMAL; }; PixelInputType LightVertexShader(VertexInputType input) { PixelInputType output; // Change the position vector to be 4 units for proper matrix calculations. input.position.w = 1.0f; // Calculate the position of the vertex against the world, view, and projection matrices. output.position = mul(input.position, worldMatrix); output.position = mul(output.position, viewMatrix); output.position = mul(output.position, projectionMatrix); // Store the texture coordinates for the pixel shader. output.tex = input.tex; // Calculate the normal vector against the world matrix only. output.normal = mul(input.normal, (float3x3)worldMatrix); // Normalize the normal vector. output.normal = normalize(output.normal); return output; } Pixel Shader: Texture2D shaderTexture; SamplerState SampleType; cbuffer LightBuffer { float4 ambientColor; float4 diffuseColor; float3 lightDirection; float padding; }; struct PixelInputType { float4 position : SV_POSITION; float2 tex : TEXCOORD0; float3 normal : NORMAL; }; float4 LightPixelShader(PixelInputType input) : SV_TARGET { float4 textureColor; float3 lightDir; float lightIntensity; float4 color; // Sample the pixel color from the texture using the sampler at this texture coordinate location. textureColor = shaderTexture.Sample(SampleType, input.tex); // Set the default output color to the ambient light value for all pixels. color = ambientColor; // Invert the light direction for calculations. lightDir = -lightDirection; // Calculate the amount of light on this pixel. lightIntensity = saturate(dot(input.normal, lightDir)); if(lightIntensity > 0.0f) { // Determine the final diffuse color based on the diffuse color and the amount of light intensity. color += (diffuseColor * lightIntensity); } // Saturate the final light color. color = saturate(color); // Multiply the texture pixel and the final diffuse color to get the final pixel color result. color = color * textureColor; return color; }

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First-Time GLSL Shadow Mapping Problems

- by Locke

I'm working on building out a 2.5D engine and having massive problems getting my shadows working. I'm at a point where I'm VERY close. So, let's see a picture to see what I have: As you can see above, the image has lighting -- but the shadow map is displaying incorrectly. The shadow map is shown in the bottom left hand side of the screen as a normal 2D texture, so we can see what it looks like at any given time. If you notice, it appears that the shadows are generating backwards in the wrong direction -- I think. But the problem is a little more deep -- I'm just plotting the shadow onto the screen, which I know is wrong -- I'm ignoring the actual test to see if we NEED to show a shadow. The incoming parameters all appear to be correct -- so there has to be something wrong with my shader code somewhere. Here's what my code looks like: VERTEX: uniform mat4 LightModelViewProjectionMatrix; varying vec3 Normal; // The eye-space normal of the current vertex. varying vec4 LightCoordinate; // The texture coordinate of the light of the current vertex. varying vec3 LightDirection; // The eye-space direction of the light. void main() { Normal = normalize(gl_NormalMatrix * gl_Normal); LightDirection = normalize(gl_NormalMatrix * gl_LightSource[0].position.xyz); LightCoordinate = LightModelViewProjectionMatrix * gl_Vertex; LightCoordinate.xy = ( LightCoordinate.xy * 0.5 ) + 0.5; gl_Position = ftransform(); gl_TexCoord[0] = gl_MultiTexCoord0; } FRAGMENT: uniform sampler2D DiffuseMap; uniform sampler2D ShadowMap; varying vec3 Normal; // The eye-space normal of the current vertex. varying vec4 LightCoordinate; // The texture coordinate of the light of the current vertex. varying vec3 LightDirection; // The eye-space direction of the light. void main() { vec4 Texel = texture2D(DiffuseMap, vec2(gl_TexCoord[0])); // Directional lighting //Build ambient lighting vec4 AmbientElement = gl_LightSource[0].ambient; //Build diffuse lighting float Lambert = max(dot(Normal, LightDirection), 0.0); //max(abs(dot(Normal, LightDirection)), 0.0); vec4 DiffuseElement = ( gl_LightSource[0].diffuse * Lambert ); vec4 LightingColor = ( DiffuseElement + AmbientElement ); LightingColor.r = min(LightingColor.r, 1.0); LightingColor.g = min(LightingColor.g, 1.0); LightingColor.b = min(LightingColor.b, 1.0); LightingColor.a = min(LightingColor.a, 1.0); LightingColor *= Texel; //Everything up to this point is PERFECT // Shadow mapping // ------------------------------ vec4 ShadowCoordinate = LightCoordinate / LightCoordinate.w; float DistanceFromLight = texture2D( ShadowMap, ShadowCoordinate.st ).z; float DepthBias = 0.001; float ShadowFactor = 1.0; if( LightCoordinate.w > 0.0 ) { ShadowFactor = DistanceFromLight < ( ShadowCoordinate.z + DepthBias ) ? 0.5 : 1.0; } LightingColor.rgb *= ShadowFactor; //gl_FragColor = LightingColor; //Yes, I know this is wrong, but the line above (gl_FragColor = LightingColor;) produces the wrong effect gl_FragColor = LightingColor * texture2D( ShadowMap, ShadowCoordinate.st ); } I wanted to make sure the coordinates were correct for the shadow map -- so that's why you see it applied to the image as it is below. But the depth for each point seems to be wrong -- the shadows SHOULD be opposite (look at how the image is -- the shaded areas from normal lighting are facing the opposite direction of the shadows). Maybe my matrices are bad or something going in? They're isolated and appear to be correct -- nothing else is going in unusual. When I view from the light's view and get the MVP matrices for it, they're correct. EDIT: Added an image so you can see what happens when I do the correct command at the end of the GLSL: That's the image when the last line is just glFragColor = LightingColor; Maybe someone has some idea of what I screwed up?

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Getting FEATURE_LEVEL_9_3 to work in DX11

- by Dominic

Currently I'm going through some tutorials and learning DX11 on a DX10 machine (though I just ordered a new DX11 compatible computer) by means of setting the D3D_FEATURE_LEVEL_ setting to 10_0 and switching the vertex and pixel shader versions in D3DX11CompileFromFile to "vs_4_0" and "ps_4_0" respectively. This works fine as I'm not using any DX11-only features yet. I'd like to make it compatible with DX9.0c, which naively I thought I could do by changing the feature level setting to 9_3 or something and taking the vertex/pixel shader versions down to 3 or 2. However, no matter what I change the vertex/pixel shader versions to, it always fails when I try to call D3DX11CompileFromFile to compile the vertex/pixel shader files when I have D3D_FEATURE_LEVEL_9_3 enabled. Maybe this is due to the the vertex/pixel shader files themselves being incompatible for the lower vertex/pixel shader versions, but I'm not expert enough to say. My shader files are listed below: Vertex shader: cbuffer MatrixBuffer { matrix worldMatrix; matrix viewMatrix; matrix projectionMatrix; }; struct VertexInputType { float4 position : POSITION; float2 tex : TEXCOORD0; float3 normal : NORMAL; }; struct PixelInputType { float4 position : SV_POSITION; float2 tex : TEXCOORD0; float3 normal : NORMAL; }; PixelInputType LightVertexShader(VertexInputType input) { PixelInputType output; // Change the position vector to be 4 units for proper matrix calculations. input.position.w = 1.0f; // Calculate the position of the vertex against the world, view, and projection matrices. output.position = mul(input.position, worldMatrix); output.position = mul(output.position, viewMatrix); output.position = mul(output.position, projectionMatrix); // Store the texture coordinates for the pixel shader. output.tex = input.tex; // Calculate the normal vector against the world matrix only. output.normal = mul(input.normal, (float3x3)worldMatrix); // Normalize the normal vector. output.normal = normalize(output.normal); return output; } Pixel Shader: Texture2D shaderTexture; SamplerState SampleType; cbuffer LightBuffer { float4 ambientColor; float4 diffuseColor; float3 lightDirection; float padding; }; struct PixelInputType { float4 position : SV_POSITION; float2 tex : TEXCOORD0; float3 normal : NORMAL; }; float4 LightPixelShader(PixelInputType input) : SV_TARGET { float4 textureColor; float3 lightDir; float lightIntensity; float4 color; // Sample the pixel color from the texture using the sampler at this texture coordinate location. textureColor = shaderTexture.Sample(SampleType, input.tex); // Set the default output color to the ambient light value for all pixels. color = ambientColor; // Invert the light direction for calculations. lightDir = -lightDirection; // Calculate the amount of light on this pixel. lightIntensity = saturate(dot(input.normal, lightDir)); if(lightIntensity > 0.0f) { // Determine the final diffuse color based on the diffuse color and the amount of light intensity. color += (diffuseColor * lightIntensity); } // Saturate the final light color. color = saturate(color); // Multiply the texture pixel and the final diffuse color to get the final pixel color result. color = color * textureColor; return color; }

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HLSL 5 interpolation issues

- by metredigm

I'm having issues with the depth components of my shadowmapping shaders. The shadow map rendering shader is fine, and works very well. The world rendering shader is more problematic. The only value which seems to definitely be off is the pixel's position from the light's perspective, which I pass in parallel to the position. struct Pixel { float4 position : SV_Position; float4 light_pos : TEXCOORD2; float3 normal : NORMAL; float2 texcoord : TEXCOORD; }; The reason that I used the semantic 'TEXCOORD2' on the light's pixel position is because I believe that the problem lies with Direct3D's interpolation of values between shaders, and I started trying random semantics and also forcing linear and noperspective interpolations. In the world rendering shader, I observed in the pixel shader that the Z value of light_pos was always extremely close to, but less than the W value. This resulted in a depth result of 0.999 or similar for every pixel. Here is the vertex shader code : struct Vertex { float3 position : POSITION; float3 normal : NORMAL; float2 texcoord : TEXCOORD; }; struct Pixel { float4 position : SV_Position; float4 light_pos : TEXCOORD2; float3 normal : NORMAL; float2 texcoord : TEXCOORD; }; cbuffer Camera : register (b0) { matrix world; matrix view; matrix projection; }; cbuffer Light : register (b1) { matrix light_world; matrix light_view; matrix light_projection; }; Pixel RenderVertexShader(Vertex input) { Pixel output; output.position = mul(float4(input.position, 1.0f), world); output.position = mul(output.position, view); output.position = mul(output.position, projection); output.world_pos = mul(float4(input.position, 1.0f), world); output.world_pos = mul(output.world_pos, light_view); output.world_pos = mul(output.world_pos, light_projection); output.texcoord = input.texcoord; output.normal = input.normal; return output; } I suspect interpolation to be the culprit, as I used the camera matrices in place of the light matrices in the vertex shader, and had the same problem. The problem is evident as both of the same vectors were passed to a pixel from the VS, but only one of them showed a change in the PS. I have already thoroughly debugged the matrices' validity, the cbuffers' validity, and the multiplicative validity. I'm very stumped and have been trying to solve this for quite some time. Misc info : The light projection matrix and the camera projection matrix are the same, generated from D3DXMatrixPerspectiveFovLH(), with an FOV of 60.0f * 3.141f / 180.0f, a near clipping plane of 0.1f, and a far clipping plane of 1000.0f. Any ideas on what is happening? (This is a repost from my question on Stack Overflow)

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What Counts For a DBA – Depth

- by Louis Davidson

SQL Server offers very simple interfaces to many of its features. Most people could open up SSMS, connect to a server, write a simple query and see the results. Even several of the core DBA tasks are deceptively straightforward. It doesn’t take a rocket scientist to perform a basic database backup or run a trace (even using the newfangled Extended Events!). However, appearances can be deceptive, and often times it is really important that a DBA understands not just the basics of how to perform a task, but why we do a task, and how that task works. As an analogy, consider a child walking into a darkened room. Most would know that they need to turn on the light, and how to do it, so they flick the switch. But what happens if light fails to shine forth. Most would immediately tell you that you need to consider changing the light bulb. So you hop in the car and take them to the local home store and instruct them to buy a replacement. Confronted with a 40 foot display of light bulbs, how will they decide which of the hundreds of types of bulbs, of different types, fittings, shapes, colors, power and efficiency ratings, is the right choice? Obviously the main lesson the child is going to learn this day is how to use their cell phone as a flashlight so they don’t have to ask for help the next time. Likewise, when the metaphorical toddlers who use your database server have issues, they will instinctively know something is wrong, and may even have some idea what caused it, but will have no depth of knowledge to figure out the right solution. That is where the DBA comes in and attempts to save the day. However, when one looks beneath the shiny UI, SQL Server has its own “40 foot display of light bulbs”, in the form of the tremendous number of tools and the often-bewildering amount of information they can present to the DBA, to help us find issues. Unfortunately, resorting to guesswork, to trying different “bulbs” over and over, hoping to stumble on the answer. This is where the right depth of knowledge goes a long way. If we need to write a SELECT statement, then knowing the syntax and where to find the data is not enough. Knowledge of indexes and query plans is essential. Without it, we might hit on a query that “works”, but we are basically still a user, not a programmer, because we have no real control over our platform. Is that level of knowledge deep enough? Probably not, since knowledge of the underlying metadata and structures would be very useful in helping us make sense of any query plan. Understanding the structure of an index makes the “key lookup” operator not sound like what you do when someone tapes your car key to the ceiling. So is even this level of understanding deep enough? Do we need to understand the memory architecture used to process the query? It might be a comforting level of knowledge, and will doubtless come in handy at some point, but is not strictly necessary in most cases. Beyond that lies (more or less) full knowledge of SQL language and the intricacies of every step the SQL Server engine takes to process our query. My personal theory is that, as a professional, our knowledge of a given task should extend, at a minimum, one level deeper than is strictly necessary to perform the task. Anything deeper can be left to the ridiculously smart, or obsessive, or both. As an example. tasked with storing an integer value between 0 and 99999999, it’s essential that I know that choosing an Integer over Decimal(8,0) will likely offer performance benefits. It is then useful that I also understand the value of adding a CHECK constraint, to make sure the values are valid to the desired range; and comforting that I know a little about the underlying processors, registers and computer math. Anything further, I leave to the likes of Joe Chang, whose recent blog post on the topic offers depth by the bucketful!

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Changelog file: YAML vs JSON vs CSV

- by Aziz Light

Hello everybody. I am creating a simple Changelog lib in CodeIgniter that will basically log a message everytime someone adds, deletes, changes or publish a blog post. I will log messages in files by batches of 300. So every 301st message will go in a new file. At first I wanted to write the logs to simple .log files but then I got the idea to actually style the thing and I had to seperate each "attribute" of each message (ie: the user, the message, the type of the log, etc.). So .log files are out of the question since extracting the info would be a pain. What is the most appropriate format for such a task? I already ruled out MySQL and XML because they are too heavy (especially considering that the log files won't exceed (about) 300 lines). I suggested YAML vs JSON vs CSV in the title, but is there yet a better alternative?

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T SQL Rotate row into columns

- by cshah

SQL 2005 using T-SQL, I want to rotate rows into columns. Sample script: Use TempDB Go CREATE TABLE [dbo].[CPPrinter_InkLevels]( [CPPrinter_InkLevels_ID] [int] IDENTITY(1,1) NOT NULL, [CPMeasurementGUID] [uniqueidentifier] NOT NULL, [InkName] [varchar](30) NOT NULL, [InkLevel] [decimal](6, 2) NOT NULL, CONSTRAINT [PK_CPPrinter_InkLevels] PRIMARY KEY CLUSTERED ( [CPPrinter_InkLevels_ID] ASC )WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY] ) ON [PRIMARY] GO SET IDENTITY_INSERT [dbo].[CPPrinter_InkLevels] ON INSERT [dbo].[CPPrinter_InkLevels] ([CPPrinter_InkLevels_ID], [CPMeasurementGUID], [InkName], [InkLevel]) VALUES (1, N'6acc1562-4e02-45ff-b480-9e01fb97fccf', N'Black', CAST(0.60 AS Decimal(6, 2))) INSERT [dbo].[CPPrinter_InkLevels] ([CPPrinter_InkLevels_ID], [CPMeasurementGUID], [InkName], [InkLevel]) VALUES (2, N'6acc1562-4e02-45ff-b480-9e01fb97fccf', N'Cyan', CAST(0.69 AS Decimal(6, 2))) INSERT [dbo].[CPPrinter_InkLevels] ([CPPrinter_InkLevels_ID], [CPMeasurementGUID], [InkName], [InkLevel]) VALUES (3, N'6acc1562-4e02-45ff-b480-9e01fb97fccf', N'Magenta', CAST(0.55 AS Decimal(6, 2))) INSERT [dbo].[CPPrinter_InkLevels] ([CPPrinter_InkLevels_ID], [CPMeasurementGUID], [InkName], [InkLevel]) VALUES (4, N'6acc1562-4e02-45ff-b480-9e01fb97fccf', N'Yellow', CAST(0.51 AS Decimal(6, 2))) INSERT [dbo].[CPPrinter_InkLevels] ([CPPrinter_InkLevels_ID], [CPMeasurementGUID], [InkName], [InkLevel]) VALUES (5, N'6acc1562-4e02-45ff-b480-9e01fb97fccf', N'Light Black', CAST(0.64 AS Decimal(6, 2))) INSERT [dbo].[CPPrinter_InkLevels] ([CPPrinter_InkLevels_ID], [CPMeasurementGUID], [InkName], [InkLevel]) VALUES (6, N'6acc1562-4e02-45ff-b480-9e01fb97fccf', N'Light Cyan', CAST(0.43 AS Decimal(6, 2))) INSERT [dbo].[CPPrinter_InkLevels] ([CPPrinter_InkLevels_ID], [CPMeasurementGUID], [InkName], [InkLevel]) VALUES (7, N'6acc1562-4e02-45ff-b480-9e01fb97fccf', N'Light Magenta', CAST(0.30 AS Decimal(6, 2))) INSERT [dbo].[CPPrinter_InkLevels] ([CPPrinter_InkLevels_ID], [CPMeasurementGUID], [InkName], [InkLevel]) VALUES (8, N'6acc1562-4e02-45ff-b480-9e01fb97fccf', N'Waste Tank', CAST(0.18 AS Decimal(6, 2))) INSERT [dbo].[CPPrinter_InkLevels] ([CPPrinter_InkLevels_ID], [CPMeasurementGUID], [InkName], [InkLevel]) VALUES (9, N'932348a7-6e2f-4a10-9760-be1ae640c7d7', N'Black', CAST(0.60 AS Decimal(6, 2))) INSERT [dbo].[CPPrinter_InkLevels] ([CPPrinter_InkLevels_ID], [CPMeasurementGUID], [InkName], [InkLevel]) VALUES (10, N'932348a7-6e2f-4a10-9760-be1ae640c7d7', N'Cyan', CAST(0.69 AS Decimal(6, 2))) INSERT [dbo].[CPPrinter_InkLevels] ([CPPrinter_InkLevels_ID], [CPMeasurementGUID], [InkName], [InkLevel]) VALUES (11, N'932348a7-6e2f-4a10-9760-be1ae640c7d7', N'Magenta', CAST(0.55 AS Decimal(6, 2))) INSERT [dbo].[CPPrinter_InkLevels] ([CPPrinter_InkLevels_ID], [CPMeasurementGUID], [InkName], [InkLevel]) VALUES (12, N'932348a7-6e2f-4a10-9760-be1ae640c7d7', N'Yellow', CAST(0.51 AS Decimal(6, 2))) INSERT [dbo].[CPPrinter_InkLevels] ([CPPrinter_InkLevels_ID], [CPMeasurementGUID], [InkName], [InkLevel]) VALUES (13, N'932348a7-6e2f-4a10-9760-be1ae640c7d7', N'Light Black', CAST(0.64 AS Decimal(6, 2))) INSERT [dbo].[CPPrinter_InkLevels] ([CPPrinter_InkLevels_ID], [CPMeasurementGUID], [InkName], [InkLevel]) VALUES (14, N'932348a7-6e2f-4a10-9760-be1ae640c7d7', N'Light Cyan', CAST(0.43 AS Decimal(6, 2))) Go SELECT * FROM [dbo].[CPPrinter_InkLevels] --Desired output CPMeasuremnetGUID, Ink1, Level1, Ink2, Level2, Ink3, Level3....

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ASP.NET Client to Server communication

- by Nelson

Can you help me make sense of all the different ways to communicate from browser to client in ASP.NET? I have made this a community wiki so feel free to edit my post to improve it. Specifically, I'm trying to understand in which scenario to use each one by listing how each works. I'm a little fuzzy on UpdatePanel vs CallBack (with ViewState): I know UpdatePanel always returns HTML while CallBack can return JSON. Any other major differences? ...and CallBack (without ViewState) vs WebMethod. CallBack goes through most of the Page lifecycle, WebMethod doesn't. Any other major differences? IHttpHandler Custom handler for anything (page, image, etc.) Only does what you tell it to do (light server processing) Page is an implementation of IHttpHandler If you don't need what Page provides, create a custom IHttpHandler If you are using Page but overriding Render() and not generating HTML, you probably can do it with a custom IHttpHandler (e.g. writing binary data such as images) By default can use the .axd or .ashx file extensions -- both are functionally similar .ashx doesn't have any built-in endpoints, so it's preferred by convention Regular PostBack (System.Web.UI.Page : IHttpHandler) Inherits Page Full PostBack, including ViewState and HTML control values (heavy traffic) Full Page lifecycle (heavy server processing) No JavaScript required Webpage flickers/scrolls since everything is reloaded in browser Returns full page HTML (heavy traffic) UpdatePanel (Control) Control inside Page Full PostBack, including ViewState and HTML control values (heavy traffic) Full Page lifecycle (heavy server processing) Controls outside the UpdatePanel do Render(NullTextWriter) Must use ScriptManager If no client-side JavaScript, it can fall back to regular PostBack with no JavaScript (?) No flicker/scroll since it's an async call, unless it falls back to regular postback. Can be used with master pages and user controls Has built-in support for progress bar Returns HTML for controls inside UpdatePanel (medium traffic) Client CallBack (Page, System.Web.UI.ICallbackEventHandler) Inherits Page Most of Page lifecycle (heavy server processing) Takes only data you specify (light traffic) and optionally ViewState (?) (medium traffic) Client must support JavaScript and use ScriptManager No flicker/scroll since it's an async call Can be used with master pages and user controls Returns only data you specify in format you specify (e.g. JSON, XML...) (?) (light traffic) WebMethod Class implements System.Web.Service.WebService HttpContext available through this.Context Takes only data you specify (light traffic) Server only runs the called method (light server processing) Client must support JavaScript No flicker/scroll since it's an async call Can be used with master pages and user controls Returns only data you specify, typically JSON (light traffic) Can create instance of server control to render HTML and sent back as string, but events, paging in GridView, etc. won't work PageMethods Essentially a WebMethod contained in the Page class, so most of WebMethod's bullet's apply Method must be public static, therefore no Page instance accessible HttpContext available through HttpContext.Current Accessed directly by URL Page.aspx/MethodName (e.g. with XMLHttpRequest directly or with library such as jQuery) Setting ScriptManager property EnablePageMethods="True" generates a JavaScript proxy for each WebMethod Cannot be used directly in user controls with master pages and user controls Any others?

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What (kind of) project could I create to learn JavaScript?

- by Aziz Light

Hello, I started learning JavaScript a while ago. It's a fairly easy programming language considering that I learned Java in university, that I know php pretty well and that I already played around with python and ruby. The problem is that to properly learn a programming language I usually create a project. In javascript, I just don't know what kind of project I could create - that is, a project that is not web-based or related to the web browser. Can I create javascript shell scripts? Where is javascript commonly used beside the web browsers? So, can someone actually give me some ideas please?

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Problem implementing Blinn–Phong shading model

- by Joe Hopfgartner

I did this very simple, perfectly working, implementation of Phong Relflection Model (There is no ambience implemented yet, but that doesn't bother me for now). The functions should be self explaining. /** * Implements the classic Phong illumination Model using a reflected light * vector. */ public class PhongIllumination implements IlluminationModel { @RGBParam(r = 0, g = 0, b = 0) public Vec3 ambient; @RGBParam(r = 1, g = 1, b = 1) public Vec3 diffuse; @RGBParam(r = 1, g = 1, b = 1) public Vec3 specular; @FloatParam(value = 20, min = 1, max = 200.0f) public float shininess; /* * Calculate the intensity of light reflected to the viewer . * * @param P = The surface position expressed in world coordinates. * * @param V = Normalized viewing vector from surface to eye in world * coordinates. * * @param N = Normalized normal vector at surface point in world * coordinates. * * @param surfaceColor = surfaceColor Color of the surface at the current * position. * * @param lights = The active light sources in the scene. * * @return Reflected light intensity I. */ public Vec3 shade(Vec3 P, Vec3 V, Vec3 N, Vec3 surfaceColor, Light lights[]) { Vec3 surfaceColordiffused = Vec3.mul(surfaceColor, diffuse); Vec3 totalintensity = new Vec3(0, 0, 0); for (int i = 0; i < lights.length; i++) { Vec3 L = lights[i].calcDirection(P); N = N.normalize(); V = V.normalize(); Vec3 R = Vec3.reflect(L, N); // reflection vector float diffuseLight = Vec3.dot(N, L); float specularLight = Vec3.dot(V, R); if (diffuseLight > 0) { totalintensity = Vec3.add(Vec3.mul(Vec3.mul( surfaceColordiffused, lights[i].calcIntensity(P)), diffuseLight), totalintensity); if (specularLight > 0) { Vec3 Il = lights[i].calcIntensity(P); Vec3 Ilincident = Vec3.mul(Il, Math.max(0.0f, Vec3 .dot(N, L))); Vec3 intensity = Vec3.mul(Vec3.mul(specular, Ilincident), (float) Math.pow(specularLight, shininess)); totalintensity = Vec3.add(totalintensity, intensity); } } } return totalintensity; } } Now i need to adapt it to become a Blinn-Phong illumination model I used the formulas from hearn and baker, followed pseudocodes and tried to implement it multiple times according to wikipedia articles in several languages but it never worked. I just get no specular reflections or they are so weak and/or are at the wrong place and/or have the wrong color. From the numerous wrong implementations I post some little code that already seems to be wrong. So I calculate my Half Way vector and my new specular light like so: Vec3 H = Vec3.mul(Vec3.add(L.normalize(), V), Vec3.add(L.normalize(), V).length()); float specularLight = Vec3.dot(H, N); With theese little changes it should already work (maby not with correct intensity but basically it should be correct). But the result is wrong. Here are two images. Left how it should render correctly and right how it renders. If i lower the shininess factor you can see a little specular light at the top right: Altough I understand the concept of Phong illumination and also the simplified more performant adaptaion of blinn phong I am trying around for days and just cant get it to work. Any help is appriciated. Edit: I was made aware of an error by this answer, that i am mutiplying by |L+V| instead of dividing by it when calculating H. I changed to deviding doing so: Vec3 H = Vec3.mul(Vec3.add(L.normalize(), V), 1/Vec3.add(L.normalize(), V).length()); Unfortunately this doesnt change much. The results look like this: and if I rise the specular constant and lower the shininess You can see the effects more clearly in a smilar wrong way: However this division just the normalisation. I think I am missing one step. Because the formulas like this just dont make sense to me. If you look at this picture: http://en.wikipedia.org/wiki/File:Blinn-Phong_vectors.svg The projection of H to N is far less than V to R. And if you imagine changing the vector V in the picture the angle is the same when the viewing vector is "on the left side". and becomes more and more different when going to the right. I pesonally would multiply the whole projection by two to become something similiar (and the hole point is to avoid the calculation of R). Altough I didnt read anythinga bout that anywehre i am gonna try this out... Result: The intension of the specular light is far too much (white areas) and the position is still wrong. I think I am messing something else up because teh reflection are just at the wrong place. But what? Edit: Now I read on wikipedia in the notes that the angle of N/H is in fact approximalty half or V/R. To compensate that i should multiply my shineness exponent by 4 rather than my projection. If i do that I end up with this: Far to intense but still one thing. The projection is at the wrong place. Where could i mess up my vectors?

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Are Symphony and CakePHP too slow to be usable?

- by Aziz Light

Until now, I have always said that CakePHP is too bloated and slow. I don't really know that, I just saw "some" benchmarks. What I really want to know, is that if those two frameworks (Symfony and CakePHP) are too slow to be usable in a way that the user will get frustrated. I already know that those frameworks are slower than other alternatives, but that's not the question. I ask the question because I want to create a project management web application and I still hesitate between a couple frameworks. I've had some trouble learning Zend, but imho I haven't tried hard enough. So in conclusion, in addition to the first question above, I would like to ask another question: If I want to create a project management tool (which is a pretty big project), which of the following should you suggest, considering the developement time, the speed of the resulting application, and the robustness of the final product: Symphony CakePHP Zend Framework Also I should mention that I don't know any of those frameworks, and that I want to learn one of them (at least).

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Django: ordering by backward related field property

- by Silver Light

Hello! I have two models related one-to-many: a Post and a Comment: class Post(models.Model): title = models.CharField(max_length=200); content = models.TextField(); class Comment(models.Model): post = models.ForeignKey('Post'); body = models.TextField(); date_added = models.DateTimeField(); I want to get a list of posts, ordered by the date of the latest comment. If I would write a custom SQL query it would look like this: SELECT `posts`.`*`, MAX(`comments`.`date_added`) AS `date_of_lat_comment` FROM `posts`, `comments` WHERE `posts`.`id` = `comments`.`post_id` GROUP BY `posts`.`id` ORDER BY `date_of_lat_comment` DESC How can I do same thing using django ORM?

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Django: Get remote IP address inside settings.py

- by Silver Light

Hello! I want to enable debug (DEBUG = True) For my Django project only if it runs on localhost. How can I get user IP address inside settings.py? I would like something like this to work: #Debugging only on localhost if user_ip = '127.0.0.1': DEBUG = True else: DEBUG = False How do I put user IP address in user_ip variable inside settings.py file?

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Django: Paginator + raw SQL query

- by Silver Light

Hello! I'm using Django Paginator everywhere on my website and even wrote a special template tag, to make it more convenient. But now I got to a state, where I need to make a complex custom raw SQL query, that without a LIMIT will return about 100K records. How can I use Django Pagintor with custom query? Simplified example of my problem: My model: class PersonManager(models.Manager): def complicated_list(self): from django.db import connection #Real query is much more complex cursor.execute("""SELECT * FROM `myapp_person`"""); result_list = [] for row in cursor.fetchall(): result_list.append(row[0]); return result_list class Person(models.Model): name = models.CharField(max_length=255); surname = models.CharField(max_length=255); age = models.IntegerField(); objects = PersonManager(); The way I use pagintation with Django ORM: all_objects = Person.objects.all(); paginator = Paginator(all_objects, 10); try: page = int(request.GET.get('page', '1')) except ValueError: page = 1 try: persons = paginator.page(page) except (EmptyPage, InvalidPage): persons = paginator.page(paginator.num_pages) This way, Django get very smart, and adds LIMIT to a query when executing it. But when I use custom manager: all_objects = Person.objects.complicated_list(); all data is selected, and only then python list is sliced, which is VERY slow. How can I make my custom manager behave similar like built in one?

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Can Android OS be programmed to interface with a external device via the mini-USB port?

- by user322865

Basic example, if I bought a chipset with a light socket and bulb soldered to the chipset; then put a USB cable with the mini-USB plug on the end to get plugged into the android phone. Can I write a Java application to turn on/off the light, get the status of the light(on/off) and maybe power a super-small led/bulb with power from the phone itself? Any insight at all would be greatly appreciated. Thank you

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How to change tab background on viewpagerindicator tabs?

- by user1736277

I am using ViewpagerIndicator library by Jake Wharton. I am using the tabs code in conjunction with the ActionBarSherlock library. Everything works fine, but I'm trying to style the background of the tabs and can't figure out how. I would like a dark action bar with dark tabs and light fragments (tab content). The base theme I am using is Theme.Sherlock.Light.DarkActionBar. I extend this style by making it the parent of a style that sets attributes for the tabs (like text color, indicator color, etc). This results in dark actionbar, light tabs, and light fragments. I can't find anything that will change the background of the tabs themselves. The only way I can change it is by changing the whole app to dark (using Theme.Sherlock). Here's my code so far: <style name="vpiTheme" parent="Theme.Sherlock.Light.DarkActionBar"> <item name="vpiTabPageIndicatorStyle">@style/CustomTabPageIndicator</item> </style> <style name="CustomTabPageIndicator" parent="Widget.TabPageIndicator"> <item name="android:textColor">#FF000000</item> <item name="android:paddingTop">6dp</item> <item name="android:paddingBottom">6dp</item> <item name="android:paddingLeft">16dip</item> <item name="android:paddingRight">16dip</item> <item name="android:maxLines">2</item> </style>

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