iPhone 3D Batching

[Qube]

Hi

Is there a way to batch draw 3D models in order to reduce draw calls on the iPhone?

I use polyvector when doing 2D to draw many sprites in between startpoly / endpoly in order to reduce draw calls and that works well but I see no solution for 3D, unless I'm missing something obvious 

I've see some referral to glDrawArrays but I've no idea if that is the right thing to use or indeed how it could be used 

[bigsofty]

You could use GLDrawArrays (or glDrawElements I think) but that would require Gernot to expose some of the internal GLBasic data structures he uses for storing meshes? Some sort of mesh Batching command would be a great addition in GLBasic, even good old Blitz3D has this.

[Qube]

Some sort of mesh Batching command would be a great addition in GLBasic

I agree, a mesh batching feature would be very handy for GLB and iPhone  **VOTE FOR FEATURE**

[Kitty Hello]

That's what I already am doing. I render each X_DRAWOBJ in one batch.
Do you want more in one batch? It must be the same texture, mind!

[bigsofty]

Yes, that would be great Gernot, doing a bunch of X_DRAWOBJ calls for a single call would be a big boost. 

A mesh combiner command is also something to consider too...

"X_ADDMESH mesh1, mesh2, newmesh"

Where all the vertices in "mesh1" are added to "mesh2" which would create a new mesh "newmesh". See... B3D AddMesh

[matchy]

That would mean that X_SETTEXTURE would need to include the object number.

[Kitty Hello]

No - you cannot switch texture within drawing a batch of triangles.
I'll see what I can do.

[Scott_AW]

You could combine some textures into a 'tilemap' and manipulate the texture x,y accordingly.

That would be useful to be able to batch like textured objects.

[matchy]

I thought I'd try it out:

Code (glbasic) Select Expand


// --------------------------------- //
// Project: texdouble
// Start: Thursday, Aprl 22, 2010
// IDE Version: 7.322
// Name: matchy
// Description: Experimental demonstration of combining inital separate texture maps for separate textured objects.

CONSTANT SPRITE_TEXTURE1=1
CONSTANT SPRITE_TEXTURE2=2
CONSTANT OBJECT_BOX1=1
CONSTANT OBJECT_BOX2=2
CONSTANT BRUSH_HORIZONTAL_LINES=1
CONSTANT BRUSH_VERTICAL_LINES=2
CONSTANT COL_WHITE=0xffffff
CONSTANT COL_RED=0x0000ff
CONSTANT COL_GREEN=0x00ff00
CONSTANT COL_BLUE=0xff0000
GLOBAL SPRITE_TEXTURE3


funStart()

FUNCTION funStart:
SETSCREEN 640,480, 0

SPRITE_TEXTURE3=GENSPRITE()
funCreateTextureSprite(SPRITE_TEXTURE1,BRUSH_HORIZONTAL_LINES, 128,128, COL_GREEN)
funCreateTextureSprite(SPRITE_TEXTURE2,BRUSH_VERTICAL_LINES,   128,128, COL_BLUE)

funCreateFlatObject(OBJECT_BOX1, -2,0,0, 1,1,1, 0.1,0.9, COL_WHITE)
funCreateFlatObject(OBJECT_BOX2,  2,0,0, 1,1,1, 0.1,0.9, COL_WHITE)

SPRITE_TEXTURE3=funAddTexture(SPRITE_TEXTURE1,SPRITE_TEXTURE2)

WHILE TRUE
X_MAKE3D 1,10, 45
X_CAMERA 0,1,10, 0,0,0

// Display separate objects with separate textures

X_MOVEMENT 0,1,0
X_SETTEXTURE SPRITE_TEXTURE1,-1
X_DRAWOBJ OBJECT_BOX1, 0
X_SETTEXTURE SPRITE_TEXTURE2,-1
X_DRAWOBJ OBJECT_BOX2, 0

// Display combined texture from original separate textures

X_MOVEMENT 0,-1,0
X_SETTEXTURE SPRITE_TEXTURE3,-1
X_DRAWOBJ OBJECT_BOX1, 0
X_SETTEXTUREOFFSET 0.5,0
X_DRAWOBJ OBJECT_BOX2, 0
SHOWSCREEN
WEND
ENDFUNCTION

FUNCTION funAddTexture: texture1,texture2
LOCAL w1,h1, w2,h2, w3,h3, texture3

GETSPRITESIZE texture1, w1,h1
GETSPRITESIZE texture2, w2,h2
w3=w1+w2
h3=h1 //+h2
CLEARSCREEN
DRAWSPRITE texture1,  0,0
DRAWSPRITE texture2, w1,0
GRABSPRITE texture3,  0,0, w3,h3
RETURN texture3
ENDFUNCTION

FUNCTION funCreateTextureSprite: sprite,brush, w,h, col
LOCAL x,y

CLEARSCREEN
SELECT brush
CASE BRUSH_HORIZONTAL_LINES
FOR y=0 TO h STEP 5
DRAWLINE 0,y, w,y, col
NEXT
CASE BRUSH_VERTICAL_LINES
FOR x=0 TO w STEP 5
DRAWLINE x,0, x,h, col
NEXT
ENDSELECT
GRABSPRITE sprite, 0,0, w,h
ENDFUNCTION

FUNCTION funCreateFlatObject: num, x,y,z, l,w,h, tw,th, col
l=l*0.5
w=w*0.5
h=h*0.5
X_OBJSTART num
X_OBJADDVERTEX x-l, y+w, z+h,  0,  0, col
X_OBJADDVERTEX x+l, y+w, z+h, tw,  0, col
X_OBJADDVERTEX x-l, y-w, z+h,  0, th, col
X_OBJADDVERTEX x+l, y-w, z+h, tw, th, col
X_OBJNEWGROUP
X_OBJEND
ENDFUNCTION