Merge "Update AHardwareBuffer and ANativeWindow documentation."
diff --git a/libs/nativewindow/include/android/hardware_buffer.h b/libs/nativewindow/include/android/hardware_buffer.h
index 9ca4941..52b4582 100644
--- a/libs/nativewindow/include/android/hardware_buffer.h
+++ b/libs/nativewindow/include/android/hardware_buffer.h
@@ -15,12 +15,31 @@
*/
/**
- * @addtogroup NativeActivity Native Activity
- * @{
- */
-
-/**
* @file hardware_buffer.h
+ * @brief API for native hardware buffers.
+ */
+/**
+ * @defgroup AHardwareBuffer Native Hardware Buffer
+ *
+ * AHardwareBuffer objects represent chunks of memory that can be
+ * accessed by various hardware components in the system. It can be
+ * easily converted to the Java counterpart
+ * android.hardware.HardwareBuffer and passed between processes using
+ * Binder. All operations involving AHardwareBuffer and HardwareBuffer
+ * are zero-copy, i.e., passing AHardwareBuffer to another process
+ * creates a shared view of the same region of memory.
+ *
+ * AHardwareBuffers can be bound to EGL/OpenGL and Vulkan primitives.
+ * For EGL, use the extension function eglGetNativeClientBufferANDROID
+ * to obtain an EGLClientBuffer and pass it directly to
+ * eglCreateImageKHR. Refer to the EGL extensions
+ * EGL_ANDROID_get_native_client_buffer and
+ * EGL_ANDROID_image_native_buffer for more information. In Vulkan,
+ * the contents of the AHardwareBuffer can be accessed as external
+ * memory. See the VK_ANDROID_external_memory_android_hardware_buffer
+ * extension for details.
+ *
+ * @{
*/
#ifndef ANDROID_HARDWARE_BUFFER_H
@@ -37,7 +56,7 @@
/**
* Buffer pixel formats.
*/
-enum {
+enum AHardwareBuffer_Format {
/**
* Corresponding formats:
* Vulkan: VK_FORMAT_R8G8B8A8_UNORM
@@ -83,8 +102,10 @@
AHARDWAREBUFFER_FORMAT_R10G10B10A2_UNORM = 0x2b,
/**
- * An opaque binary blob format that must have height 1, with width equal to
- * the buffer size in bytes.
+ * Opaque binary blob format.
+ * Must have height 1 and one layer, with width equal to the buffer
+ * size in bytes. Corresponds to Vulkan buffers and OpenGL buffer
+ * objects. Can be bound to the latter using GL_EXT_external_buffer.
*/
AHARDWAREBUFFER_FORMAT_BLOB = 0x21,
@@ -134,21 +155,39 @@
/**
* Buffer usage flags, specifying how the buffer will be accessed.
*/
-enum {
- /// The buffer will never be read by the CPU.
+enum AHardwareBuffer_UsageFlags {
+ /// The buffer will never be locked for direct CPU reads using the
+ /// AHardwareBuffer_lock() function. Note that reading the buffer
+ /// using OpenGL or Vulkan functions or memory mappings is still
+ /// allowed.
AHARDWAREBUFFER_USAGE_CPU_READ_NEVER = 0UL,
- /// The buffer will sometimes be read by the CPU.
+ /// The buffer will sometimes be locked for direct CPU reads using
+ /// the AHardwareBuffer_lock() function. Note that reading the
+ /// buffer using OpenGL or Vulkan functions or memory mappings
+ /// does not require the presence of this flag.
AHARDWAREBUFFER_USAGE_CPU_READ_RARELY = 2UL,
- /// The buffer will often be read by the CPU.
+ /// The buffer will often be locked for direct CPU reads using
+ /// the AHardwareBuffer_lock() function. Note that reading the
+ /// buffer using OpenGL or Vulkan functions or memory mappings
+ /// does not require the presence of this flag.
AHARDWAREBUFFER_USAGE_CPU_READ_OFTEN = 3UL,
/// CPU read value mask.
AHARDWAREBUFFER_USAGE_CPU_READ_MASK = 0xFUL,
- /// The buffer will never be written by the CPU.
+ /// The buffer will never be locked for direct CPU writes using the
+ /// AHardwareBuffer_lock() function. Note that writing the buffer
+ /// using OpenGL or Vulkan functions or memory mappings is still
+ /// allowed.
AHARDWAREBUFFER_USAGE_CPU_WRITE_NEVER = 0UL << 4,
- /// The buffer will sometimes be written to by the CPU.
+ /// The buffer will sometimes be locked for direct CPU writes using
+ /// the AHardwareBuffer_lock() function. Note that writing the
+ /// buffer using OpenGL or Vulkan functions or memory mappings
+ /// does not require the presence of this flag.
AHARDWAREBUFFER_USAGE_CPU_WRITE_RARELY = 2UL << 4,
- /// The buffer will often be written to by the CPU.
+ /// The buffer will often be locked for direct CPU writes using
+ /// the AHardwareBuffer_lock() function. Note that writing the
+ /// buffer using OpenGL or Vulkan functions or memory mappings
+ /// does not require the presence of this flag.
AHARDWAREBUFFER_USAGE_CPU_WRITE_OFTEN = 3UL << 4,
/// CPU write value mask.
AHARDWAREBUFFER_USAGE_CPU_WRITE_MASK = 0xFUL << 4,
@@ -156,24 +195,51 @@
/// The buffer will be read from by the GPU as a texture.
AHARDWAREBUFFER_USAGE_GPU_SAMPLED_IMAGE = 1UL << 8,
/**
- * The buffer will be written to by the GPU as a framebuffer attachment.
- * Note that the name of this flag is somewhat misleading: it does not imply
- * that the buffer contains a color format. A buffer with depth or stencil
- * format that will be used as a framebuffer attachment should also have
- * this flag.
+ * The buffer will be written to by the GPU as a framebuffer
+ * attachment.
+ *
+ * Note that the name of this flag is somewhat misleading: it does
+ * not imply that the buffer contains a color format. A buffer with
+ * depth or stencil format that will be used as a framebuffer
+ * attachment should also have this flag.
*/
AHARDWAREBUFFER_USAGE_GPU_COLOR_OUTPUT = 1UL << 9,
- /// The buffer must not be used outside of a protected hardware path.
+ /**
+ * The buffer is protected from direct CPU access or being read by
+ * non-secure hardware, such as video encoders.
+ *
+ * This flag is incompatible with CPU read and write flags. It is
+ * mainly used when handling DRM video. Refer to the EGL extension
+ * EGL_EXT_protected_content and GL extension
+ * GL_EXT_protected_textures for more information on how these
+ * buffers are expected to behave.
+ */
AHARDWAREBUFFER_USAGE_PROTECTED_CONTENT = 1UL << 14,
/// The buffer will be read by a hardware video encoder.
AHARDWAREBUFFER_USAGE_VIDEO_ENCODE = 1UL << 16,
- /// The buffer will be used for direct writes from sensors.
+ /**
+ * The buffer will be used for direct writes from sensors.
+ * When this flag is present, the format must be AHARDWAREBUFFER_FORMAT_BLOB.
+ */
AHARDWAREBUFFER_USAGE_SENSOR_DIRECT_DATA = 1UL << 23,
- /// The buffer will be used as a shader storage or uniform buffer object.
+ /**
+ * The buffer will be used as a shader storage or uniform buffer object.
+ * When this flag is present, the format must be AHARDWAREBUFFER_FORMAT_BLOB.
+ */
AHARDWAREBUFFER_USAGE_GPU_DATA_BUFFER = 1UL << 24,
- /// The buffer will be used as a cube map texture.
+ /**
+ * The buffer will be used as a cube map texture.
+ * When this flag is present, the buffer must have a layer count
+ * that is a multiple of 6. Note that buffers with this flag must be
+ * bound to OpenGL textures using the extension
+ * GL_EXT_EGL_image_storage instead of GL_KHR_EGL_image.
+ */
AHARDWAREBUFFER_USAGE_GPU_CUBE_MAP = 1UL << 25,
- /// The buffer contains a complete mipmap hierarchy.
+ /**
+ * The buffer contains a complete mipmap hierarchy.
+ * Note that buffers with this flag must be bound to OpenGL textures using
+ * the extension GL_EXT_EGL_image_storage instead of GL_KHR_EGL_image.
+ */
AHARDWAREBUFFER_USAGE_GPU_MIPMAP_COMPLETE = 1UL << 26,
AHARDWAREBUFFER_USAGE_VENDOR_0 = 1ULL << 28,
@@ -199,27 +265,42 @@
};
/**
- * Buffer description. Used for allocating new buffers and querying parameters
- * of existing ones.
+ * Buffer description. Used for allocating new buffers and querying
+ * parameters of existing ones.
*/
typedef struct AHardwareBuffer_Desc {
uint32_t width; ///< Width in pixels.
uint32_t height; ///< Height in pixels.
- uint32_t layers; ///< Number of images in an image array.
- uint32_t format; ///< One of AHARDWAREBUFFER_FORMAT_*
- uint64_t usage; ///< Combination of AHARDWAREBUFFER_USAGE_*
+ /**
+ * Number of images in an image array. AHardwareBuffers with one
+ * layer correspond to regular 2D textures. AHardwareBuffers with
+ * more than layer correspond to texture arrays. If the layer count
+ * is a multiple of 6 and the usage flag
+ * AHARDWAREBUFFER_USAGE_GPU_CUBE_MAP is present, the buffer is
+ * a cube map or a cube map array.
+ */
+ uint32_t layers;
+ uint32_t format; ///< One of AHardwareBuffer_Format.
+ uint64_t usage; ///< Combination of AHardwareBuffer_UsageFlags.
uint32_t stride; ///< Row stride in pixels, ignored for AHardwareBuffer_allocate()
uint32_t rfu0; ///< Initialize to zero, reserved for future use.
uint64_t rfu1; ///< Initialize to zero, reserved for future use.
} AHardwareBuffer_Desc;
+/**
+ * Opaque handle for a native hardware buffer.
+ */
typedef struct AHardwareBuffer AHardwareBuffer;
#if __ANDROID_API__ >= 26
/**
- * Allocates a buffer that backs an AHardwareBuffer using the passed
- * AHardwareBuffer_Desc.
+ * Allocates a buffer that matches the passed AHardwareBuffer_Desc.
+ *
+ * If allocation succeeds, the buffer can be used according to the
+ * usage flags specified in its description. If a buffer is used in ways
+ * not compatible with its usage flags, the results are undefined and
+ * may include program termination.
*
* \return 0 on success, or an error number of the allocation fails for
* any reason. The returned buffer has a reference count of 1.
@@ -227,14 +308,16 @@
int AHardwareBuffer_allocate(const AHardwareBuffer_Desc* desc,
AHardwareBuffer** outBuffer) __INTRODUCED_IN(26);
/**
- * Acquire a reference on the given AHardwareBuffer object. This prevents the
- * object from being deleted until the last reference is removed.
+ * Acquire a reference on the given AHardwareBuffer object.
+ *
+ * This prevents the object from being deleted until the last reference
+ * is removed.
*/
void AHardwareBuffer_acquire(AHardwareBuffer* buffer) __INTRODUCED_IN(26);
/**
* Remove a reference that was previously acquired with
- * AHardwareBuffer_acquire().
+ * AHardwareBuffer_acquire() or AHardwareBuffer_allocate().
*/
void AHardwareBuffer_release(AHardwareBuffer* buffer) __INTRODUCED_IN(26);
@@ -246,50 +329,73 @@
AHardwareBuffer_Desc* outDesc) __INTRODUCED_IN(26);
/**
- * Lock the AHardwareBuffer for reading or writing, depending on the usage flags
- * passed. This call may block if the hardware needs to finish rendering or if
- * CPU caches need to be synchronized, or possibly for other implementation-
- * specific reasons. If fence is not negative, then it specifies a fence file
- * descriptor that will be signaled when the buffer is locked, otherwise the
- * caller will block until the buffer is available.
+ * Lock the AHardwareBuffer for direct CPU access.
*
- * If \a rect is not NULL, the caller promises to modify only data in the area
- * specified by rect. If rect is NULL, the caller may modify the contents of the
- * entire buffer.
+ * This function can lock the buffer for either reading or writing.
+ * It may block if the hardware needs to finish rendering, if CPU caches
+ * need to be synchronized, or possibly for other implementation-
+ * specific reasons.
*
- * The content of the buffer outside of the specified rect is NOT modified
- * by this call.
+ * The passed AHardwareBuffer must have one layer, otherwise the call
+ * will fail.
*
- * The \a usage parameter may only specify AHARDWAREBUFFER_USAGE_CPU_*. If set,
- * then outVirtualAddress is filled with the address of the buffer in virtual
+ * If \a fence is not negative, it specifies a fence file descriptor on
+ * which to wait before locking the buffer. If it's negative, the caller
+ * is responsible for ensuring that writes to the buffer have completed
+ * before calling this function. Using this parameter is more efficient
+ * than waiting on the fence and then calling this function.
+ *
+ * The \a usage parameter may only specify AHARDWAREBUFFER_USAGE_CPU_*.
+ * If set, then outVirtualAddress is filled with the address of the
+ * buffer in virtual memory. The flags must also be compatible with
+ * usage flags specified at buffer creation: if a read flag is passed,
+ * the buffer must have been created with
+ * AHARDWAREBUFFER_USAGE_CPU_READ_RARELY or
+ * AHARDWAREBUFFER_USAGE_CPU_READ_OFTEN. If a write flag is passed, it
+ * must have been created with AHARDWAREBUFFER_USAGE_CPU_WRITE_RARELY or
+ * AHARDWAREBUFFER_USAGE_CPU_WRITE_OFTEN.
+ *
+ * If \a rect is not NULL, the caller promises to modify only data in
+ * the area specified by rect. If rect is NULL, the caller may modify
+ * the contents of the entire buffer. The content of the buffer outside
+ * of the specified rect is NOT modified by this call.
+ *
+ * It is legal for several different threads to lock a buffer for read
+ * access; none of the threads are blocked.
+ *
+ * Locking a buffer simultaneously for write or read/write is undefined,
+ * but will neither terminate the process nor block the caller.
+ * AHardwareBuffer_lock may return an error or leave the buffer's
+ * content in an indeterminate state.
+ *
+ * If the buffer has AHARDWAREBUFFER_FORMAT_BLOB, it is legal lock it
+ * for reading and writing in multiple threads and/or processes
+ * simultaneously, and the contents of the buffer behave like shared
* memory.
*
- * THREADING CONSIDERATIONS:
- *
- * It is legal for several different threads to lock a buffer for read access;
- * none of the threads are blocked.
- *
- * Locking a buffer simultaneously for write or read/write is undefined, but
- * will neither terminate the process nor block the caller; AHardwareBuffer_lock
- * may return an error or leave the buffer's content into an indeterminate
- * state.
- *
- * \return 0 on success, -EINVAL if \a buffer is NULL or if the usage
- * flags are not a combination of AHARDWAREBUFFER_USAGE_CPU_*, or an error
- * number of the lock fails for any reason.
+ * \return 0 on success. -EINVAL if \a buffer is NULL, the usage flags
+ * are not a combination of AHARDWAREBUFFER_USAGE_CPU_*, or the buffer
+ * has more than one layer. Error number if the lock fails for any other
+ * reason.
*/
int AHardwareBuffer_lock(AHardwareBuffer* buffer, uint64_t usage,
int32_t fence, const ARect* rect, void** outVirtualAddress) __INTRODUCED_IN(26);
/**
- * Unlock the AHardwareBuffer; must be called after all changes to the buffer
- * are completed by the caller. If fence is not NULL then it will be set to a
- * file descriptor that is signaled when all pending work on the buffer is
- * completed. The caller is responsible for closing the fence when it is no
- * longer needed.
+ * Unlock the AHardwareBuffer from direct CPU access.
*
- * \return 0 on success, -EINVAL if \a buffer is NULL, or an error
- * number if the unlock fails for any reason.
+ * Must be called after all changes to the buffer are completed by the
+ * caller. If \a fence is NULL, the function will block until all work
+ * is completed. Otherwise, \a fence will be set either to a valid file
+ * descriptor or to -1. The file descriptor will become signaled once
+ * the unlocking is complete and buffer contents are updated.
+ * The caller is responsible for closing the file descriptor once it's
+ * no longer needed. The value -1 indicates that unlocking has already
+ * completed before the function returned and no further operations are
+ * necessary.
+ *
+ * \return 0 on success. -EINVAL if \a buffer is NULL. Error number if
+ * the unlock fails for any reason.
*/
int AHardwareBuffer_unlock(AHardwareBuffer* buffer, int32_t* fence) __INTRODUCED_IN(26);
@@ -302,7 +408,7 @@
int AHardwareBuffer_sendHandleToUnixSocket(const AHardwareBuffer* buffer, int socketFd) __INTRODUCED_IN(26);
/**
- * Receive the AHardwareBuffer from an AF_UNIX socket.
+ * Receive an AHardwareBuffer from an AF_UNIX socket.
*
* \return 0 on success, -EINVAL if \a outBuffer is NULL, or an error
* number if the operation fails for any reason.
diff --git a/libs/nativewindow/include/android/native_window.h b/libs/nativewindow/include/android/native_window.h
index 6831f91..6730596 100644
--- a/libs/nativewindow/include/android/native_window.h
+++ b/libs/nativewindow/include/android/native_window.h
@@ -15,7 +15,13 @@
*/
/**
- * @addtogroup NativeActivity Native Activity
+ * @defgroup ANativeWindow Native Window
+ *
+ * ANativeWindow represents the producer end of an image queue.
+ * It is the C counterpart of the android.view.Surface object in Java,
+ * and can be converted both ways. Depending on the consumer, images
+ * submitted to ANativeWindow can be shown on the display or sent to
+ * other consumers, such as video encoders.
* @{
*/
@@ -41,7 +47,7 @@
* Legacy window pixel format names, kept for backwards compatibility.
* New code and APIs should use AHARDWAREBUFFER_FORMAT_*.
*/
-enum {
+enum ANativeWindow_LegacyFormat {
// NOTE: these values must match the values from graphics/common/x.x/types.hal
/** Red: 8 bits, Green: 8 bits, Blue: 8 bits, Alpha: 8 bits. **/
@@ -95,7 +101,7 @@
/// memory. This may be >= width.
int32_t stride;
- /// The format of the buffer. One of AHARDWAREBUFFER_FORMAT_*
+ /// The format of the buffer. One of AHardwareBuffer_Format.
int32_t format;
/// The actual bits.
@@ -151,7 +157,7 @@
*
* \param width width of the buffers in pixels.
* \param height height of the buffers in pixels.
- * \param format one of AHARDWAREBUFFER_FORMAT_* constants.
+ * \param format one of the AHardwareBuffer_Format constants.
* \return 0 for success, or a negative value on error.
*/
int32_t ANativeWindow_setBuffersGeometry(ANativeWindow* window,
