Good news, gyus!
I've found a way to get rid of garbage collection!
The receipt is simple (and ironic): do not use allocateDirect(), use
allocate(). And use only ByteBuffer, not FloatBuffer, IntBuffer, etc.
- using asFloatBuffer() on non-direct ByteBuffer will result in crash
in libhgl. (I'm too lazy to create an issue for that.)
E.g. this code:
ByteBuffer vbb = ByteBuffer.allocateDirect(vertices.length*4);
vbb.order(ByteOrder.nativeOrder());
mVertexBuffer = vbb.asIntBuffer();
mVertexBuffer.put(vertices);
mVertexBuffer.position(0);
should be
ByteBuffer vbb = ByteBuffer.allocate(vertices.length*4);
vbb.order(ByteOrder.nativeOrder());
for (int vertex: vertices) {
mVertexBuffer.putInt(vertex);
}
mVertexBuffer.position(0);
and voila, no garbage collections on ADP 1.5 firmware.
Please test and report your results here.
Dmitry
On 16 июл, 21:33, PaulT <dr.paul.thomas.android.st...@googlemail.com>
wrote:
> Hello everybody,
>
> I've created a simple OpenGL app and created a rendering class which
> implements GLSurfaceView.Renderer. All it does is draw 100 triangles
> (NUM_OBJECTS = 100) on the screen and move them about, bouncing off
> the edges. The projection is glOrtho2D and there is no z-buffer. I'm
> running this on a G1 with continuous redraw enabled.
>
> Here is the onDrawFrame method:
>
> public void onDrawFrame(GL10 gl) {
> gl.glClear(GL10.GL_COLOR_BUFFER_BIT);
> for (n = 0; n < NUM_OBJECTS; n++) {
> gl.glPushMatrix();
> gl.glTranslatef(posX[n], posY[n], 0);
> gl.glVertexPointer(2, GL10.GL_FLOAT, 0, vBuffer);
> gl.glDrawElements(GL10.GL_TRIANGLES, 3, GL10.GL_UNSIGNED_SHORT,
> iBuffer);
> gl.glPopMatrix();
> posX[n] += xa[n];
> posY[n] += ya[n];
> if (posX[n] > viewW || posX[n] < 0) {
> xa[n] = -xa[n];
> }
> if (posY[n] > viewH || posY[n] < 0) {
> ya[n] = -ya[n];
> }
> }
>
> }
>
> It's pretty simple stuff just to get an idea of the device
> performance. Note that I am not leaking any garbage in this method.
>
> If we look at the logs while this is running,
>
> D/dalvikvm( 3085): GC freed 21840 objects / 524256 bytes in 153ms
> D/dalvikvm( 3085): GC freed 21842 objects / 524304 bytes in 156ms
> D/dalvikvm( 3085): GC freed 21840 objects / 524256 bytes in 157ms
> D/dalvikvm( 3085): GC freed 21842 objects / 524304 bytes in 155ms
> D/dalvikvm( 3085): GC freed 21840 objects / 524256 bytes in 156ms
> D/dalvikvm( 3085): GC freed 21842 objects / 524304 bytes in 156ms
> D/dalvikvm( 3085): GC freed 21840 objects / 524256 bytes in 157ms
> D/dalvikvm( 3085): GC freed 21842 objects / 524304 bytes in 155ms
> D/dalvikvm( 3085): GC freed 21840 objects / 524256 bytes in 152ms
> D/dalvikvm( 3085): GC freed 21842 objects / 524304 bytes in 155ms
> D/dalvikvm( 3085): GC freed 21840 objects / 524256 bytes in 150ms
> D/dalvikvm( 3085): GC freed 21842 objects / 524304 bytes in 155ms
> D/dalvikvm( 3085): GC freed 21840 objects / 524256 bytes in 153ms
> D/dalvikvm( 3085): GC freed 21842 objects / 524304 bytes in 155ms
> D/dalvikvm( 3085): GC freed 21840 objects / 524256 bytes in 157ms
> D/dalvikvm( 3085): GC freed 21842 objects / 524304 bytes in 155ms
> D/dalvikvm( 3085): GC freed 21840 objects / 524256 bytes in 151ms
> D/dalvikvm( 3085): GC freed 21842 objects / 524304 bytes in 159ms
> D/dalvikvm( 3085): GC freed 21840 objects / 524256 bytes in 155ms
> D/dalvikvm( 3085): GC freed 21842 objects / 524304 bytes in 156ms
> D/dalvikvm( 3085): GC freed 21840 objects / 524256 bytes in 153ms
> D/dalvikvm( 3085): GC freed 21842 objects / 524304 bytes in 158ms
> D/dalvikvm( 3085): GC freed 21840 objects / 524256 bytes in 151ms
>
> Every few seconds, the garbage collector has a bit of a tidy up. If
> we look at the frame rate, it is averaging out to be around 56Hz. I
> speculate that the system can keep up with the 60Hz vertical sync just
> fine until it needs to collect garbage.
>
> Nothing else is running so this stuff is definitely coming from this
> app. Unfortunately it causes the display to pause briefly (160ms is
> about 10 frames) so would not be acceptable in an interactive game.
> Does anybody know what causes this (something in the OpenGL code?) and
> can it be avoided?
>
> Thanks for any help.
>
> Paul.
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