- Use Android SurfaceView for rendering surface.
- In native code, create a rendering thread and call OpenGL for rendering in the same thread.
1. Workflow
2. Demo
Source code can be found on my github page: https://github.com/chuzcjoe/nativegl
On Android side, we start/stop rendering at different stages of the SurfaceView lifecycle.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
| class SurfaceViewHolder : SurfaceHolder.Callback {
override fun surfaceChanged(holder: SurfaceHolder, format: Int, w: Int, h: Int) {
JNIProxy.setSurface(holder.surface)
JNIProxy.startRender()
}
override fun surfaceCreated(holder: SurfaceHolder) {
JNIProxy.calPixel()
JNIProxy.setSurface(holder.surface)
JNIProxy.startRender()
}
override fun surfaceDestroyed(holder: SurfaceHolder) {
JNIProxy.stopRender()
JNIProxy.setSurface(null)
}
}
|
To start rendering, we will start a new rendering thread. In this new thread, we will initialize EGL settings and start drawing with OpenGL APIs.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
| void GLBase::StartRenderThread(){
if (!init){
_th = std::thread(RenderThread, this);
init = !init;
}
running = true;
}
void GLBase::RenderThread(GLBase* obj){
obj->RenderLoop();
}
void GLBase::RenderLoop(){
bool rendering = true;
while (rendering) {
if (running){
if (eglSetting._msg == EGLSetting::RenderThreadMessage::MSG_WINDOW_SET) {
initEGL();
}
if (eglSetting._msg == EGLSetting::RenderThreadMessage::MSG_RENDER_LOOP_EXIT) {
rendering = false;
DestroyRender();
}
eglSetting._msg = EGLSetting::RenderThreadMessage::MSG_NONE;
if (!window_set) {
usleep(16000);
continue;
}
if (eglSetting._display) {
std::lock_guard<std::mutex> lock(eglSetting._mutex);
DrawFrame();
if (!eglSwapBuffers(eglSetting._display, eglSetting._surface)) {
LOG_INFO("GLrenderS::eglSwapBuffers() returned error %d", eglGetError());
}
} else {
usleep(16000);
}
} else {
usleep(16000);
}
}
}
|
If everything works well, you should see a green triangle at the center of the screen.
