minus.android.support.opengl

Class GLTextureView

java.lang.Object

TextureView

minus.android.support.opengl.GLTextureView

public class GLTextureView
extends TextureView

An implementation of TextureView that uses the dedicated surface for displaying OpenGL rendering.

A GLTextureView provides the following features:

• Manages a surface, which is a special piece of memory that can be composited into the Android view system.
• Manages an EGL display, which enables OpenGL to render into a surface.
• Accepts a user-provided Renderer object that does the actual rendering.
• Renders on a dedicated thread to decouple rendering performance from the UI thread.
• Supports both on-demand and continuous rendering.
• Optionally wraps, traces, and/or error-checks the renderer's OpenGL calls.

Developer Guides

For more information about how to use OpenGL, read the OpenGL developer guide.

Using GLTextureView

Typically you use GLTextureView by subclassing it and overriding one or more of the View system input event methods. If your application does not need to override event methods then GLTextureView can be used as-is. For the most part GLTextureView behavior is customized by calling "set" methods rather than by subclassing. For example, unlike a regular View, drawing is delegated to a separate Renderer object which is registered with the GLTextureView using the setRenderer(Renderer) call.

Initializing GLTextureView

All you have to do to initialize a GLTextureView is call setRenderer(Renderer). However, if desired, you can modify the default behavior of GLTextureView by calling one or more of these methods before calling setRenderer:

• setDebugFlags(int)
• setEGLConfigChooser(boolean)
• setEGLConfigChooser(EGLConfigChooser)
• setEGLConfigChooser(int, int, int, int, int, int)
• setGLWrapper(GLWrapper)

Specifying the android.view.Surface

By default GLTextureView will create a PixelFormat.RGB_888 format surface. If a translucent surface is required, call getHolder().setFormat(PixelFormat.TRANSLUCENT). The exact format of a TRANSLUCENT surface is device dependent, but it will be a 32-bit-per-pixel surface with 8 bits per component.

Choosing an EGL Configuration

A given Android device may support multiple EGLConfig rendering configurations. The available configurations may differ in how may channels of data are present, as well as how many bits are allocated to each channel. Therefore, the first thing GLTextureView has to do when starting to render is choose what EGLConfig to use.

By default GLTextureView chooses a EGLConfig that has an RGB_888 pixel format, with at least a 16-bit depth buffer and no stencil.

If you would prefer a different EGLConfig you can override the default behavior by calling one of the setEGLConfigChooser methods.

Debug Behavior

You can optionally modify the behavior of GLTextureView by calling one or more of the debugging methods setDebugFlags(int), and setGLWrapper(minus.android.support.opengl.GLTextureView.GLWrapper). These methods may be called before and/or after setRenderer, but typically they are called before setRenderer so that they take effect immediately.

Setting a Renderer

Finally, you must call setRenderer(minus.android.support.opengl.GLTextureView.Renderer) to register a GLTextureView.Renderer. The renderer is responsible for doing the actual OpenGL rendering.

Rendering Mode

Once the renderer is set, you can control whether the renderer draws continuously or on-demand by calling setRenderMode(int). The default is continuous rendering.

Activity Life-cycle

A GLTextureView must be notified when the activity is paused and resumed. GLTextureView clients are required to call onPause() when the activity pauses and onResume() when the activity resumes. These calls allow GLTextureView to pause and resume the rendering thread, and also allow GLTextureView to release and recreate the OpenGL display.

Handling events

To handle an event you will typically subclass GLTextureView and override the appropriate method, just as you would with any other View. However, when handling the event, you may need to communicate with the Renderer object that's running in the rendering thread. You can do this using any standard Java cross-thread communication mechanism. In addition, one relatively easy way to communicate with your renderer is to call queueEvent(Runnable). For example:

 class MyGLTextureView extends GLTextureView {

     private MyRenderer mMyRenderer;

     public void start() {
         mMyRenderer = ...;
         setRenderer(mMyRenderer);
     }

     public boolean onKeyDown(int keyCode, KeyEvent event) {
         if (keyCode == KeyEvent.KEYCODE_DPAD_CENTER) {
             queueEvent(new Runnable() {
                 // This method will be called on the rendering
                 // thread:
                 public void run() {
                     mMyRenderer.handleDpadCenter();
                 }});
             return true;
         }
         return super.onKeyDown(keyCode, event);
     }
 }
 

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static interface	GLTextureView.EGLConfigChooser An interface for choosing an EGLConfig configuration from a list of potential configurations.
static interface	GLTextureView.EGLContextFactory An interface for customizing the eglCreateContext and eglDestroyContext calls.
static interface	GLTextureView.EGLWindowSurfaceFactory An interface for customizing the eglCreateWindowSurface and eglDestroySurface calls.
static interface	GLTextureView.GLWrapper An interface used to wrap a GL interface.
static interface	GLTextureView.Renderer A generic renderer interface.

Field Summary

Fields

Modifier and Type	Field and Description
static int	DEBUG_CHECK_GL_ERROR Check glError() after every GL call and throw an exception if glError indicates that an error has occurred.
static int	DEBUG_LOG_GL_CALLS Log GL calls to the system log at "verbose" level with tag "GLTextureView".
static int	RENDERMODE_CONTINUOUSLY The renderer is called continuously to re-render the scene.
static int	RENDERMODE_WHEN_DIRTY The renderer only renders when the surface is created, or when requestRender() is called.

Constructor Summary

Constructors

Constructor and Description
GLTextureView(Context context) Standard View constructor.
GLTextureView(Context context, AttributeSet attrs) Standard View constructor.

Method Summary

Modifier and Type	Method and Description
protected void	finalize()
int	getDebugFlags() Get the current value of the debug flags.
boolean	getPreserveEGLContextOnPause()
int	getRenderMode() Get the current rendering mode.
protected void	onAttachedToWindow() This method is used as part of the View class and is not normally called or subclassed by clients of GLTextureView.
protected void	onDetachedFromWindow()
void	onPause() Inform the view that the activity is paused.
void	onResume() Inform the view that the activity is resumed.
void	onSurfaceTextureAvailable(SurfaceTexture surface, int width, int height)
boolean	onSurfaceTextureDestroyed(SurfaceTexture surface)
void	onSurfaceTextureSizeChanged(SurfaceTexture surface, int width, int height)
void	onSurfaceTextureUpdated(SurfaceTexture surface)
void	queueEvent(java.lang.Runnable r) Queue a runnable to be run on the GL rendering thread.
void	requestRender() Request that the renderer render a frame.
void	setDebugFlags(int debugFlags) Set the debug flags to a new value.
void	setEGLConfigChooser(boolean needDepth) Install a config chooser which will choose a config as close to 16-bit RGB as possible, with or without an optional depth buffer as close to 16-bits as possible.
void	setEGLConfigChooser(GLTextureView.EGLConfigChooser configChooser) Install a custom EGLConfigChooser.
void	setEGLConfigChooser(int redSize, int greenSize, int blueSize, int alphaSize, int depthSize, int stencilSize) Install a config chooser which will choose a config with at least the specified depthSize and stencilSize, and exactly the specified redSize, greenSize, blueSize and alphaSize.
void	setEGLContextClientVersion(int version) Inform the default EGLContextFactory and default EGLConfigChooser which EGLContext client version to pick.
void	setEGLContextFactory(GLTextureView.EGLContextFactory factory) Install a custom EGLContextFactory.
void	setEGLWindowSurfaceFactory(GLTextureView.EGLWindowSurfaceFactory factory) Install a custom EGLWindowSurfaceFactory.
void	setGLWrapper(GLTextureView.GLWrapper glWrapper) Set the glWrapper.
void	setPreserveEGLContextOnPause(boolean preserveOnPause) Control whether the EGL context is preserved when the GLTextureView is paused and resumed.
void	setRenderer(GLTextureView.Renderer renderer) Set the renderer associated with this view.
void	setRenderMode(int renderMode) Set the rendering mode.
void	setSurfaceTextureListener(SurfaceTextureListener listener) Deprecated.

Methods inherited from class java.lang.Object

clone, equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

RENDERMODE_WHEN_DIRTY

public static final int RENDERMODE_WHEN_DIRTY

The renderer only renders when the surface is created, or when requestRender() is called.

See Also:

getRenderMode(), setRenderMode(int), requestRender(), Constant Field Values

RENDERMODE_CONTINUOUSLY

public static final int RENDERMODE_CONTINUOUSLY

The renderer is called continuously to re-render the scene.

See Also:

getRenderMode(), setRenderMode(int), Constant Field Values

DEBUG_CHECK_GL_ERROR

public static final int DEBUG_CHECK_GL_ERROR

Check glError() after every GL call and throw an exception if glError indicates that an error has occurred. This can be used to help track down which OpenGL ES call is causing an error.

See Also:

getDebugFlags(), setDebugFlags(int), Constant Field Values

DEBUG_LOG_GL_CALLS

public static final int DEBUG_LOG_GL_CALLS

Log GL calls to the system log at "verbose" level with tag "GLTextureView".

See Also:

getDebugFlags(), setDebugFlags(int), Constant Field Values

Constructor Detail

GLTextureView

public GLTextureView(Context context)

Standard View constructor. In order to render something, you must call setRenderer(minus.android.support.opengl.GLTextureView.Renderer) to register a renderer.

GLTextureView

public GLTextureView(Context context,
                     AttributeSet attrs)

Standard View constructor. In order to render something, you must call setRenderer(minus.android.support.opengl.GLTextureView.Renderer) to register a renderer.

Method Detail

finalize

protected void finalize()
                 throws java.lang.Throwable

Throws:

java.lang.Throwable

setGLWrapper

public void setGLWrapper(GLTextureView.GLWrapper glWrapper)

Set the glWrapper. If the glWrapper is not null, its GLTextureView.GLWrapper.wrap(GL) method is called whenever a surface is created. A GLWrapper can be used to wrap the GL object that's passed to the renderer. Wrapping a GL object enables examining and modifying the behavior of the GL calls made by the renderer.

Wrapping is typically used for debugging purposes.

The default value is null.

Parameters:

glWrapper - the new GLWrapper

setDebugFlags

public void setDebugFlags(int debugFlags)

Set the debug flags to a new value. The value is constructed by OR-together zero or more of the DEBUG_CHECK_* constants. The debug flags take effect whenever a surface is created. The default value is zero.

Parameters:

debugFlags - the new debug flags

See Also:

DEBUG_CHECK_GL_ERROR, DEBUG_LOG_GL_CALLS

getDebugFlags

public int getDebugFlags()

Get the current value of the debug flags.

Returns:

the current value of the debug flags.

setPreserveEGLContextOnPause

public void setPreserveEGLContextOnPause(boolean preserveOnPause)

Control whether the EGL context is preserved when the GLTextureView is paused and resumed.

If set to true, then the EGL context may be preserved when the GLTextureView is paused. Whether the EGL context is actually preserved or not depends upon whether the Android device that the program is running on can support an arbitrary number of EGL contexts or not. Devices that can only support a limited number of EGL contexts must release the EGL context in order to allow multiple applications to share the GPU.

If set to false, the EGL context will be released when the GLTextureView is paused, and recreated when the GLTextureView is resumed.

The default is false.

Parameters:

preserveOnPause - preserve the EGL context when paused

getPreserveEGLContextOnPause

public boolean getPreserveEGLContextOnPause()

Returns:

true if the EGL context will be preserved when paused

setRenderer

public void setRenderer(GLTextureView.Renderer renderer)

Set the renderer associated with this view. Also starts the thread that will call the renderer, which in turn causes the rendering to start.

This method should be called once and only once in the life-cycle of a GLTextureView.

The following GLTextureView methods can only be called before setRenderer is called:

• setEGLConfigChooser(boolean)
• setEGLConfigChooser(EGLConfigChooser)
• setEGLConfigChooser(int, int, int, int, int, int)

The following GLTextureView methods can only be called after setRenderer is called:

• getRenderMode()
• onPause()
• onResume()
• queueEvent(Runnable)
• requestRender()
• setRenderMode(int)

Parameters:

renderer - the renderer to use to perform OpenGL drawing.

setEGLContextFactory

public void setEGLContextFactory(GLTextureView.EGLContextFactory factory)

Install a custom EGLContextFactory.

If this method is called, it must be called before setRenderer(Renderer) is called.

If this method is not called, then by default a context will be created with no shared context and with a null attribute list.

setEGLWindowSurfaceFactory

public void setEGLWindowSurfaceFactory(GLTextureView.EGLWindowSurfaceFactory factory)

Install a custom EGLWindowSurfaceFactory.

If this method is called, it must be called before setRenderer(Renderer) is called.

If this method is not called, then by default a window surface will be created with a null attribute list.

setEGLConfigChooser

public void setEGLConfigChooser(GLTextureView.EGLConfigChooser configChooser)

Install a custom EGLConfigChooser.

If this method is called, it must be called before setRenderer(Renderer) is called.

If no setEGLConfigChooser method is called, then by default the view will choose an EGLConfig that is compatible with the current android.view.Surface, with a depth buffer depth of at least 16 bits.

Parameters:

configChooser -

setEGLConfigChooser

public void setEGLConfigChooser(boolean needDepth)

Install a config chooser which will choose a config as close to 16-bit RGB as possible, with or without an optional depth buffer as close to 16-bits as possible.

If this method is called, it must be called before setRenderer(Renderer) is called.

If no setEGLConfigChooser method is called, then by default the view will choose an RGB_888 surface with a depth buffer depth of at least 16 bits.

Parameters:

needDepth -

setEGLConfigChooser

public void setEGLConfigChooser(int redSize,
                                int greenSize,
                                int blueSize,
                                int alphaSize,
                                int depthSize,
                                int stencilSize)

Install a config chooser which will choose a config with at least the specified depthSize and stencilSize, and exactly the specified redSize, greenSize, blueSize and alphaSize.

If this method is called, it must be called before setRenderer(Renderer) is called.

If no setEGLConfigChooser method is called, then by default the view will choose an RGB_888 surface with a depth buffer depth of at least 16 bits.

setEGLContextClientVersion

public void setEGLContextClientVersion(int version)

Inform the default EGLContextFactory and default EGLConfigChooser which EGLContext client version to pick.

Use this method to create an OpenGL ES 2.0-compatible context. Example:

     public MyView(Context context) {
         super(context);
         setEGLContextClientVersion(2); // Pick an OpenGL ES 2.0 context.
         setRenderer(new MyRenderer());
     }
 

Note: Activities which require OpenGL ES 2.0 should indicate this by setting @lt;uses-feature android:glEsVersion="0x00020000" /> in the activity's AndroidManifest.xml file.

If this method is called, it must be called before setRenderer(Renderer) is called.

This method only affects the behavior of the default EGLContexFactory and the default EGLConfigChooser. If setEGLContextFactory(EGLContextFactory) has been called, then the supplied EGLContextFactory is responsible for creating an OpenGL ES 2.0-compatible context. If setEGLConfigChooser(EGLConfigChooser) has been called, then the supplied EGLConfigChooser is responsible for choosing an OpenGL ES 2.0-compatible config.

Parameters:

version - The EGLContext client version to choose. Use 2 for OpenGL ES 2.0

setRenderMode

public void setRenderMode(int renderMode)

Set the rendering mode. When renderMode is RENDERMODE_CONTINUOUSLY, the renderer is called repeatedly to re-render the scene. When renderMode is RENDERMODE_WHEN_DIRTY, the renderer only rendered when the surface is created, or when requestRender() is called. Defaults to RENDERMODE_CONTINUOUSLY.

Using RENDERMODE_WHEN_DIRTY can improve battery life and overall system performance by allowing the GPU and CPU to idle when the view does not need to be updated.

This method can only be called after setRenderer(Renderer)

Parameters:

renderMode - one of the RENDERMODE_X constants

See Also:

RENDERMODE_CONTINUOUSLY, RENDERMODE_WHEN_DIRTY

getRenderMode

public int getRenderMode()

Get the current rendering mode. May be called from any thread. Must not be called before a renderer has been set.

Returns:

the current rendering mode.

See Also:

RENDERMODE_CONTINUOUSLY, RENDERMODE_WHEN_DIRTY

requestRender

public void requestRender()

Request that the renderer render a frame. This method is typically used when the render mode has been set to RENDERMODE_WHEN_DIRTY, so that frames are only rendered on demand. May be called from any thread. Must not be called before a renderer has been set.

setSurfaceTextureListener

@Deprecated
public void setSurfaceTextureListener(SurfaceTextureListener listener)

Deprecated.

use setRenderer(minus.android.support.opengl.GLTextureView.Renderer) instead

onSurfaceTextureAvailable

public void onSurfaceTextureAvailable(SurfaceTexture surface,
                                      int width,
                                      int height)

onSurfaceTextureSizeChanged

public void onSurfaceTextureSizeChanged(SurfaceTexture surface,
                                        int width,
                                        int height)

onSurfaceTextureDestroyed

public boolean onSurfaceTextureDestroyed(SurfaceTexture surface)

onSurfaceTextureUpdated

public void onSurfaceTextureUpdated(SurfaceTexture surface)

onPause

public void onPause()

Inform the view that the activity is paused. The owner of this view must call this method when the activity is paused. Calling this method will pause the rendering thread. Must not be called before a renderer has been set.

onResume

public void onResume()

Inform the view that the activity is resumed. The owner of this view must call this method when the activity is resumed. Calling this method will recreate the OpenGL display and resume the rendering thread. Must not be called before a renderer has been set.

queueEvent

public void queueEvent(java.lang.Runnable r)

Queue a runnable to be run on the GL rendering thread. This can be used to communicate with the Renderer on the rendering thread. Must not be called before a renderer has been set.

Parameters:

r - the runnable to be run on the GL rendering thread.

onAttachedToWindow

protected void onAttachedToWindow()

This method is used as part of the View class and is not normally called or subclassed by clients of GLTextureView.

onDetachedFromWindow

protected void onDetachedFromWindow()