On Mon, 2010-05-17 at 11:26 +0100, Neil Roberts wrote: > On Sun, 16 May 2010 14:31:30 -0400, Sam Wilson <tecywiz...@hotmail.com> wrote: > > > Hello knowledgeable clutter people, > > > > I created an actor to handle drawing sprite based animations, and I am > > wondering if it is the correct way to do it. > > - There's no need to override the pick method if the actor has no > children and you are just drawing the color to fill the actor's > allocation. The default implementation in ClutterActor will do this > for you.
So noted!
> - You might want to make a separate material for each frame that is
> private to the actor and use that to render the texture rather than
> using Cogl.set_source_texture. This will help Cogl optimize the
> rendering better because Cogl.set_source_texture effectively ends up
> editing a global convenience material which would cause a flush of
> Cogl's journal. You should also use this material to implement the
> opacity of the actor. So _frames would become an array of
> Cogl.Materials and your init function would be something like this
> (although I don't really know Vala so I'm just guessing the syntax):
>
Something else I'll change!
> ...
>
> - It's currently much more efficient to use Cogl.rectangle rather than
> the path API to draw the texture. Cogl isn't clever enough to
> recognise that the path you've created is a simple rectangle and it
> ends up having to fill the stencil buffer to render the texture into
> the path. Using Cogl.rectangle instead means it can just directly
> submit a quad to OpenGL.
I already noticed a significant speed increase when I switched to
Cogl.rectangle_with_texture_coords, on the order of about 20 times, and
on the plus side its compatible with the default bindings.
Would the above material trick still work with the
rectangle_with_texture_coords?
> - You might want to implement the setter for the 'frame' property so
> that it queues a redraw. Otherwise it would probably be difficult to
> use ClutterActor.animate to animate the property. I don't know what's
> the right way to do that in Vala.
I had that implemented (see the commented line in the init function) but
I found that updating all the SpriteActors inside a parent then calling
queue redraw on the parent was much, much faster.
Any easy way I can get both features?
> Hope that helps.
>
> - Neil
>
> > Here's my actor:
> >
> > using Cogl;
> >
> > public class SpriteActor : Clutter.Actor
> > {
> > private Texture _tex;
> > private Texture[] _frames;
> >
> > public int frame_width { get; construct set; }
> > public int frame_height { get; construct set; }
> > public int n_frames { get; construct set; }
> >
> > public int frame { get; set; }
> >
> > private SpriteActor()
> > {
> > Object();
> > }
> >
> > public SpriteActor.from_file(int width, int height,
> > int frames, string path)
> > throws GLib.Error
> > {
> > Object(frame_width: width, frame_height: height, n_frames: frames);
> >
> > _tex = new Texture.from_file(path,
> > TextureFlags.NO_SLICING,
> > PixelFormat.ANY);
> >
> > init();
> > }
> >
> > public SpriteActor.from_bitmap(int width, int height,
> > int frames, Bitmap bit)
> > {
> > Object(frame_width: width, frame_height: height, n_frames: frames);
> >
> > _tex = new Texture.from_bitmap(bit,
> > TextureFlags.NO_SLICING,
> > PixelFormat.ANY);
> >
> > init();
> > }
> >
> > private void init()
> > {
> > //this.notify["frame"].connect(() => {queue_redraw();});
> >
> > _frames = new Texture[n_frames];
> >
> > for (int i = 0; i < n_frames; i++)
> > {
> > _frames[i] = new Texture.from_sub_texture(_tex, i * frame_width,
> > 0, frame_width,
> > frame_height);
> > }
> > }
> >
> > protected override void paint()
> > {
> > Cogl.set_source_texture(_frames[frame]);
> > Cogl.path_rectangle(0, 0, width, height);
> > Cogl.path_fill();
> > }
> >
> > protected override void pick(Clutter.Color c)
> > {
> > Cogl.set_source_color4ub(c.red, c.green, c.blue, c.alpha);
> > Cogl.path_rectangle(0, 0, width, height);
> > Cogl.path_fill();
> > }
> > }
> >
> >
> > diff --git a/vapi/cogl-1.0.vapi b/vapi/cogl-1.0.vapi
> > index 9f356d3..9c2c807 100644
> > --- a/vapi/cogl-1.0.vapi
> > +++ b/vapi/cogl-1.0.vapi
> > @@ -152,6 +152,7 @@ namespace Cogl {
> > public Texture.from_bitmap (Cogl.Bitmap bmp_handle,
> > Cogl.TextureFlags flags, Cogl.PixelFormat internal_format);
> > public Texture.from_data (uint width, uint height,
> > Cogl.TextureFlags flags, Cogl.PixelFormat format, Cogl.PixelFormat
> > internal_format, uint rowstride, [CCode (array_length = false)] uchar[]
> > data);
> > public Texture.from_file (string filename, Cogl.TextureFlags
> > flags, Cogl.PixelFormat internal_format) throws GLib.Error;
> > + public Texture.from_sub_texture(Cogl.Texture full_texture, int
> > sub_x, int sub_y, int sub_width, int sub_height);
> > public int get_data (Cogl.PixelFormat format, uint rowstride,
> > uchar[] data);
> > public Cogl.PixelFormat get_format ();
> > public uint get_height ();
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