This work is licensed under the Creative Commons Attribution 4.0 International License. To view a copy of this license, visit or send a letter to Creative Commons, 444 Castro Street, Suite 900, Mountain View, California, 94041, USA. Lecture 8 - OpenGL on Android

Laura Gheorghe, Petre Eftime OpenGL ES  Cut down version of OpenGL  Fixed point support  Found in many mobile platforms (Android, iOS, Blackberry, Symbian, 3DS, etc.)  Designed for slower GPUs and CPUs 2

Laura Gheorghe, Petre Eftime Version 1.x 3  OpenGL ES 1.0 based on OpenGL 1.3 and OpenGL ES 1.1 based on OpenGL 1.5  Common and Common-Lite (only fixed point) profile  Fixed-function rendering pipeline  Reduced features: no quad and polygon primitives, no stippling, only multisample AA, reduced drawing modes, no display lists, etc.  OpenGL ES 1.1 adds better multitexture support, VBOs, clip planes, mipmap generation  Android 1.0 and higher

Laura Gheorghe, Petre Eftime Version  Based on OpenGL 2.0, but reduced fixed-function pipeline support  Not compatible with OpenGL ES 1.x  OpenGL ES Shading Language  ESSL only has forward branches and fixed iteration loops  Transforming and Lighting functions replaced by shaders  Better performance than OpenGL ES 1.x in many cases  Android 2.2 and higher

Laura Gheorghe, Petre Eftime Version  Compatible with OpenGL ES 2.0 and OpenGL 4.3  Standardized texture compression  Better texturing support  New Shading Language version with full support for integer and floating point  Improved flow control  Easier portability  Android 4.3 and higher

Laura Gheorghe, Petre Eftime GL Surface 6  Manages a surface (a region of memory which can be displayed on screen)  Manages an EGL display (an OpenGL rendering context)  Dedicated rendering thread  Can provide debug information

Laura Gheorghe, Petre Eftime EGL 7  Virtual display which contains a rendering context  2D and 3D rendering  Allows having multiple smaller surfaces on the actual screen or drawing to offscreen buffer  Used by SurfaceFlinger and other compositors (Wayland, Mir) or libraries (SDL)

Laura Gheorghe, Petre Eftime Demo 8  Create GL2JNIView and set it as a view for the activity  Constructor initializes the view private void init(boolean translucent, int depth, int stencil) { setEGLContextFactory(new ContextFactory()); setEGLConfigChooser( translucent ? new ConfigChooser(8, 8, 8, 8, depth, stencil) : new ConfigChooser(5, 6, 5, 0, depth, stencil) ); setRenderer(new Renderer()); }

Laura Gheorghe, Petre Eftime Demo 9 public EGLConfig chooseConfig(EGL10 egl, EGLDisplay display) { /* Get the number of minimally matching EGL configurations */ int[] num_config = new int[1]; egl.eglChooseConfig(display, s_configAttribs2, null, 0, num_config); int numConfigs = num_config[0]; /* Allocate then read the array of minimally matching EGL configs */ EGLConfig[] configs = new EGLConfig[numConfigs]; egl.eglChooseConfig(display, s_configAttribs2, configs, numConfigs, num_config); /* Now return the "best" one (matches rgba specifications) */ return chooseConfig(egl, display, configs); }

Laura Gheorghe, Petre Eftime Demo 10 private static class Renderer implements GLSurfaceView.Renderer { public void onDrawFrame(GL10 gl) { GL2JNILib.step(); } public void onSurfaceChanged(GL10 gl, int width, int height) { GL2JNILib.init(width, height); } public void onSurfaceCreated(GL10 gl, EGLConfig config) { // Do nothing. }

Laura Gheorghe, Petre Eftime Demo 11  setupGraphics  Compiles vertex and pixel shaders into a program  Defines Uniforms, Attributes, etc.  Sets initial camera position and viewport

Laura Gheorghe, Petre Eftime Demo 12  renderFrame  Updates camera  Sets shader program  Sets Uniforms and Attributes for current frame  Draws triangles

Laura Gheorghe, Petre Eftime Android Tools for Debugging and Profiling 13  Logging  Debugging Developer Options: Overdraw, Clipping  Profiling Developer Options: Performance metrics on screen or through ADB, Traces  Tracer for OpenGL ES: Visualize traces

Laura Gheorghe, Petre Eftime Intel GPA 14  Intel Atom processors  More information: GPU, CPU, Battery usage  More detailed analysis  Identifies possible bottlenecks  Realtime  Works over Wifi

Laura Gheorghe, Petre Eftime Vendor specific tools 15  Low level information  Different interface and capabilities for each vendor  Optimizations not always portable  PowerVR, Tegra, Adreno, etc.

Laura Gheorghe, Petre Eftime Bibliography 16   ngl.html  ndex.html

Laura Gheorghe, Petre Eftime Keywords 17  OpenGL  EGL  Fixed function pipeline  Shaders  GLSurfaceView  Profiling  Tracer