Graphics » History » Revision 18

Revision 17 (dl lud, 01/24/2020 03:14 AM) → Revision 18/46 (dl lud, 01/24/2020 03:36 AM)

h1. Graphics 

 Replicant relies on the CPU for graphics rendering, a technique known as software rendering. Using the dedicated graphics processor (GPU) currently requires non-free software on all of the supported devices. As free-software replacements are not yet available, the GPU cannot be used with Replicant for the moment (see [[GraphicsResearch]]). The software rendering is the reason why Replicant devices appear slow at times and is responsible for a lot of crashes that can happen during usage. 

 Until [[Images#Replicant-60-0003-images|Replicant 6.0 0003]] Replicant used the [[GraphicsResearch#Android-software-renderer|Android software renderer]], also known as libagl. libagl is fast, but [[Graphics#Known-issues-with-libagl|caused several issues]] due to lack of OpenGL ES (GLES) 2.0 support. 

 As of "Replicant 6.0 0004 rc1":, [[GraphicsResearch#Mesas-llvmpipe|llvmpipe]] is used as the default software renderer. llvmpipe has a more complete GLES implementation than libagl (see #705), so more apps work with it, like Firefox-based browsers or more recent WebViews (see #1780). Unfortunately, llvmpipe is too slow for certain system components, which may also able be true for some apps. Furthermore, certain apps still crash with llvmpipe, although less frequently. Usually frequentely. Usually, the screen stays black if an app does not work with llvmpipe. 

 To cater for these issues, Replicant 6.0 0004 includes a "mechanism to choose that allows choosing between llvmpipe and ligagl, on a per process basis": Such mechanism is "actually used": on the Replicant 6.0 0004 images to force some system components (bootanimation, SurfaceFlinger and system_server) to use libagl. 

 h2. Choosing the default software renderer 

 Make sure [[ADB]] is running as root and the system partition [[ADB#Modifying-the-system-partition|is mounted writable]]. 

 The following command switches between llvmpipe and libagl: 
 adb shell "grep -q "ro.libagl=1" /system/build.prop && sed "s/ro.libagl=1/ro.libagl=0/" -i /system/build.prop || sed "s/ro.libagl=0/ro.libagl=1/" -i /system/build.prop"  

 Then reboot the device. To switch back to previous renderer, run the above command again and reboot the device. 
 This method works on both Replicant 6.0 0003 and 0004. Do note that on 0003 you will start with libagl by default, whereas on 0004 the default is llvmpipe. 

 h2. Choosing the software renderer for a specific app 

 # Find out the app ID. Example: @org.gnu.icecat@ 
 # Make sure [[ADB]] is running as root and the system partition [[ADB#Modifying-the-system-partition|is mounted writable]]. 

 You can then force the app to always use libagl by creating empty file named @libGLES_android@ on it's data directory (e.g. @/data/data/org.gnu.icecat/@). Here's an example command to create such file: 
 adb shell touch /data/data/org.gnu.icecat/libGLES_android 

 You can get back to the default renderer by removing the file. Example command: 
 adb shell rm /data/data/org.gnu.icecat/libGLES_android 

 To force llvmpipe use a file named @libGLES_mesa@. 

 This method only works for Replicant 6.0 0004. 

 h2. Choosing the software renderer for a system component 

 In case the screen compositor (SurfaceFlinger) is used with llvmpipe, this could have an effect to other apps. For instance with Gallery and Orbot it happens, that some GUI elements are visible, while the main screen is black. The GUI of Simple File Manager works as long as no image is viewed in fullscreen.  

 h2. Known issues with libagl 

 * Selecting the third option besides photo and video (Panorama mode) will crash the Camera app. 
 * Video playback in the browser does not work. (issue #1533) 
 * Screenshots do not work. (see [[Screenshots]] for a workaround) 
 * Selecting wallpapers from storage does not work. 
 * Screen content is sometimes shortly visible before unlocking. (issue #1275, happens with llvmpipe as well) 
 * Previews of the windows in the tasks switcher are missing. 
 * Switching between apps, apps and the launcher or different views inside an app is sometimes slow and the device may seem unresponsive. 
 * There are issues with using folders with the Trebuchet launcher. (issue #1790, happens with llvmpipe as well) 

 h3. Popular apps from F-Droid that do not work 

 * All Firefox-based browsers like "IceCatMobile": and Orfox 
 * "Document Viewer": 
 * "LibreOffice Viewer": 
 * "RedReader": cannot display images ("upstream bug": 

 h2. See also 

 * There is a page about [[GraphicsResearch]] that gathers information to improve graphics support.