OpenGL ES performance outline

For comparison against other 3D Engines, I wanted to publish my frames per second and triangles per second results.
I just want to be sure I didn’t miss any important trick I could have used to speed everything up.

3D Engine Feature Outline:

I already explained my engine in this post. To recoup:
I have enabled :

• TexCoords
• Normals and GL_NORMALIZE
• COLOR_ARRAY
• VERTEX_ARRAY
• I draw using glDrawElements(GL_TRIANGLES,..) using an unsigned short array for the indices
• I issue a second draw command “glDrawArrays” for the UI, but switching this off doesn’t have any performance impact
• Antialiasing/Multisampling is switched on using an msaabuffer with a samplesize of 4

My interleaved Array has the following structure and a size of 26 bytes:

typedef struct _iVertex3D
{
    short uv[2];
    shortVert n; //just short[3]
    unsigned int color;
    Vertex3 v; //just float[3]
} iVertex3D;

Ideas I haven’t tried to improve performance:

• stripify all my geometrys and call glDraw(GL_TRIANGLES_STRIP,…) because then I’d have to add quite a lot of degenerate vertices to glue different parts of geometry together

Testing device:

Second Generation iPod Touch, that means MBX GPU and a ARM11 620 (533) Mhz CPU.

I tried painting using VBO’s but it didn’t change a single FPS, so I can confirm it doesn’t make a difference on MBX GPU’s!

FPS Results:

I tried different sizes of maps, that yielded different amount of vertices/triangles. I also added a column “triangles/second” to have a more stable metric of comparison against other devices/engines.

Please keep in mind I capped FPS at 30 to improve battery performance and omit unneccessary rendering!

map size	FPS	triangles	vertices	triangles/second	vertices/second
5	30	10030	6318	300900	189540
6	30	12074	7665	362220	229950
7	25.5	16163	9523	412156.5	242836.5
7	24	18063	10519	433512	252456
8	22	19207	11561	422554	254342
8	20	22045	13043	440900	260860
9	14.7	30072	18964	442058.4	278770.8

So appearently the limit here is imposed by the triangles/second, that is the amount of triangles the MBX GPU running my 3D Engine is roughly at 440000.
That would also suggest I can draw up to 14600 triangles without loosing framerate, that is without the framerate falling below 30.

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