Add SurfaceTexture bindings (#267)

Co-authored-by: Marijn Suijten <[email protected]>

ndk/CHANGELOG.md

@@ -11,6 +11,7 @@
 - native_window: Add `format()` getter and `set_buffers_geometry()` setter. (#276)
 - native_activity: Add `set_window_format()` setter. (#277)
 - native_activity: Add `set_window_flags()` to change window behavior. (#278)
+- Add `SurfaceTexture` bindings. (#267)
 
 # 0.6.0 (2022-01-05)
 

ndk/src/lib.rs

@@ -27,4 +27,6 @@ pub mod looper;
 pub mod media;
 pub mod native_activity;
 pub mod native_window;
+pub mod posix;
+pub mod surface_texture;
 pub mod trace;

ndk/src/posix.rs

@@ -0,0 +1,10 @@
+use thiserror::Error;
+
+#[derive(Debug, Error)]
+pub struct PosixError(pub i32);
+
+impl std::fmt::Display for PosixError {
+    fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
+        write!(f, "Posix Error: {}", self.0)
+    }
+}

ndk/src/surface_texture.rs

@@ -0,0 +1,172 @@
+//! Bindings for [`ASurfaceTexture`]
+//!
+//! See <https://source.android.com/devices/graphics/arch-st> for an architectural overview of
+//! [`SurfaceTexture`] internals.
+//!
+//! [`ASurfaceTexture`]: https://developer.android.com/ndk/reference/group/surface-texture
+#![cfg(feature = "api-level-28")]
+
+use super::posix::PosixError;
+use crate::native_window::NativeWindow;
+use jni_sys::{jobject, JNIEnv};
+use std::{convert::TryInto, ptr::NonNull, time::Duration};
+
+/// An opaque type to manage [`android.graphics.SurfaceTexture`] from native code
+///
+/// [`android.graphics.SurfaceTexture`]: https://developer.android.com/reference/android/graphics/SurfaceTexture
+#[derive(Debug, Eq, Hash, Ord, PartialEq, PartialOrd)]
+pub struct SurfaceTexture {
+    ptr: NonNull<ffi::ASurfaceTexture>,
+}
+
+unsafe impl Send for SurfaceTexture {}
+
+impl Drop for SurfaceTexture {
+    fn drop(&mut self) {
+        unsafe { ffi::ASurfaceTexture_release(self.ptr.as_ptr()) }
+    }
+}
+
+impl SurfaceTexture {
+    /// Assumes ownership of `ptr`
+    ///
+    /// # Safety
+    /// `ptr` must be a valid pointer to an Android [`ffi::ASurfaceTexture`].
+    pub unsafe fn from_ptr(ptr: NonNull<ffi::ASurfaceTexture>) -> Self {
+        Self { ptr }
+    }
+
+    /// Get a reference to the native [`SurfaceTexture`] from the corresponding Java object.
+    ///
+    /// # Safety
+    ///
+    /// This function should be called with a healthy JVM pointer and with a non-null
+    /// [`android.graphics.SurfaceTexture`], which must be kept alive on the Java/Kotlin side.
+    ///
+    /// The caller must keep a reference to the Java [`android.graphics.SurfaceTexture`] during the
+    /// lifetime of the returned [`SurfaceTexture`]. Failing to do so could result in the
+    /// [`SurfaceTexture`] to stop functioning properly once the Java object gets finalized.
+    /// However, this will not result in program termination.
+    ///
+    /// [`android.graphics.SurfaceTexture`]: https://developer.android.com/reference/android/graphics/SurfaceTexture
+    pub unsafe fn from_surface_texture(env: *mut JNIEnv, surface_texture: jobject) -> Option<Self> {
+        let a_surface_texture_ptr = ffi::ASurfaceTexture_fromSurfaceTexture(env, surface_texture);
+        let s = NonNull::new(a_surface_texture_ptr)?;
+        Some(SurfaceTexture::from_ptr(s))
+    }
+
+    /// Returns a pointer to the native [`ffi::ASurfaceTexture`].
+    pub fn ptr(&self) -> NonNull<ffi::ASurfaceTexture> {
+        self.ptr
+    }
+
+    /// Returns a reference to a [`NativeWindow`] (i.e. the Producer) for this [`SurfaceTexture`].
+    ///
+    /// This is equivalent to Java's:
+    /// ```java
+    /// Surface sur = new Surface(surfaceTexture);
+    /// ```
+    pub fn acquire_native_window(&self) -> Option<NativeWindow> {
+        let native_window = unsafe { ffi::ASurfaceTexture_acquireANativeWindow(self.ptr.as_ptr()) };
+        let n = NonNull::new(native_window)?;
+        Some(unsafe { NativeWindow::from_ptr(n) })
+    }
+
+    /// Attach the [`SurfaceTexture`] to the OpenGL ES context that is current on the calling
+    /// thread.
+    ///
+    /// A new OpenGL ES texture object is created and populated with the [`SurfaceTexture`] image
+    /// frame that was current at the time of the last call to
+    /// [`detach_from_gl_context()`][Self::detach_from_gl_context()]. This new texture is bound to
+    /// the `GL_TEXTURE_EXTERNAL_OES` texture target.
+    ///
+    /// This can be used to access the [`SurfaceTexture`] image contents from multiple OpenGL ES
+    /// contexts. Note, however, that the image contents are only accessible from one OpenGL ES
+    /// context at a time.
+    pub fn attach_to_gl_context(&self, tex_name: u32) -> Result<(), PosixError> {
+        let r = unsafe { ffi::ASurfaceTexture_attachToGLContext(self.ptr.as_ptr(), tex_name) };
+        if r == 0 {
+            Ok(())
+        } else {
+            Err(PosixError(r))
+        }
+    }
+
+    /// Detach the [`SurfaceTexture`] from the OpenGL ES context that owns the OpenGL ES texture
+    /// object.
+    ///
+    /// This call must be made with the OpenGL ES context current on the calling thread. The OpenGL
+    /// ES texture object will be deleted as a result of this call. After calling this method all
+    /// calls to [`update_tex_image()`][Self::update_tex_image()] will fail until a successful call
+    /// to [`attach_to_gl_context()`][Self::attach_to_gl_context()] is made.
+    ///
+    /// This can be used to access the [`SurfaceTexture`] image contents from multiple OpenGL ES
+    /// contexts. Note, however, that the image contents are only accessible from one OpenGL ES
+    /// context at a time.
+    pub fn detach_from_gl_context(&self) -> Result<(), PosixError> {
+        let r = unsafe { ffi::ASurfaceTexture_detachFromGLContext(self.ptr.as_ptr()) };
+        if r == 0 {
+            Ok(())
+        } else {
+            Err(PosixError(r))
+        }
+    }
+
+    /// Retrieve the 4x4 texture coordinate transform matrix associated with the texture image set
+    /// by the most recent call to [`update_tex_image()`][Self::update_tex_image()].
+    ///
+    /// This transform matrix maps 2D homogeneous texture coordinates of the form `(s, t, 0, 1)`
+    /// with `s` and `t` in the inclusive range `[0, 1]` to the texture coordinate that should be
+    /// used to sample that location from the texture. Sampling the texture outside of the range of
+    /// this transform is undefined.
+    ///
+    /// The matrix is stored in column-major order so that it may be passed directly to OpenGL ES
+    /// via the [`glLoadMatrixf()`] or [`glUniformMatrix4fv()`] functions.
+    ///
+    /// [`glLoadMatrixf()`]: https://www.khronos.org/registry/OpenGL-Refpages/gl2.1/xhtml/glLoadMatrix.xml
+    /// [`gluniformmatrix4fv()`]: https://www.khronos.org/registry/OpenGL-Refpages/es3.1/html/glUniform.xhtml
+    pub fn transform_matrix(&self) -> [f32; 16] {
+        let mut r = [0f32; 16];
+        unsafe { ffi::ASurfaceTexture_getTransformMatrix(self.ptr.as_ptr(), r.as_mut_ptr()) };
+        r
+    }
+
+    /// Retrieve the timestamp associated with the texture image set by the most recent call to
+    /// [`update_tex_image()`][Self::update_tex_image()].
+    ///
+    /// This timestamp is in nanoseconds, and is normally monotonically increasing. The timestamp
+    /// should be unaffected by time-of-day adjustments, and for a camera should be strictly
+    /// monotonic but for a [`MediaPlayer`] may be reset when the position is set. The specific
+    /// meaning and zero point of the timestamp depends on the source providing images to the
+    /// [`SurfaceTexture`]. Unless otherwise specified by the image source, timestamps cannot
+    /// generally be compared across [`SurfaceTexture`] instances, or across multiple program
+    /// invocations. It is mostly useful for determining time offsets between subsequent frames.
+    ///
+    /// For EGL/Vulkan producers, this timestamp is the desired present time set with the
+    /// [`EGL_ANDROID_presentation_time`] or [`VK_GOOGLE_display_timing`] extensions.
+    ///
+    /// [`MediaPlayer`]: https://developer.android.com/reference/android/media/MediaPlayer
+    /// [`EGL_ANDROID_presentation_time`]: https://www.khronos.org/registry/EGL/extensions/ANDROID/EGL_ANDROID_presentation_time.txt
+    /// [`VK_GOOGLE_display_timing`]: https://www.khronos.org/registry/vulkan/specs/1.3-extensions/man/html/VK_GOOGLE_display_timing.html
+    pub fn timestamp(&self) -> Duration {
+        Duration::from_nanos(
+            unsafe { ffi::ASurfaceTexture_getTimestamp(self.ptr.as_ptr()) }
+                .try_into()
+                .unwrap(),
+        )
+    }
+
+    /// Update the texture image to the most recent frame from the image stream.
+    ///
+    /// This may only be called while the OpenGL ES context that owns the texture is current on the
+    /// calling thread. It will implicitly bind its texture to the `GL_TEXTURE_EXTERNAL_OES`
+    /// texture target.
+    pub fn update_tex_image(&self) -> Result<(), PosixError> {
+        let r = unsafe { ffi::ASurfaceTexture_updateTexImage(self.ptr.as_ptr()) };
+        if r == 0 {
+            Ok(())
+        } else {
+            Err(PosixError(r))
+        }
+    }
+}