MiniB3d + OpenGL issue

BlitzMax Forums/MiniB3D Module/MiniB3d + OpenGL issue

jkrankie (Posted 2009) [#1]

Couldn't really think of a better title for this thread, sorry. Anyway, the code below is for a very simple single-surface particle thingy i've been writing for my game. It basically just draws textured quads. The code is also pretty custom to my own game. The code below behaves as expected, however when i incorporated it into my project, i'm getting a strange problem. Very occasionally the quads are draw un-textured, so just white squares are drawn as if glBindTexture has failed. This is obviously really annoying, but i can't work out what is causing the problem - and i don't want to blame MiniB3d outright because i'm unsure of what it's doing under the hood. however, if it is affecting gl textures in some way i'd like to know what i can do to ensure that it isn't a problem for this code. During the flow of thing in my game, i'm displaying lot's of Tmesh and TSprites, all transformed in some way, all textured, most using entityblend, entityFX and entity shininess in some way. I also use Backbuffertotex, although only once. Import sidesign.minib3d Graphics3D 640,480,32,7,60 cam=CreateCamera();PositionEntity cam,0,0,-30 light=CreateLight();PositionEntity light,0,0,-15 'load textures pix = LoadPixmap("testtex.bmp") ;tex = TexFromPixmap(pix) list:TList=New TList Local old_ms=MilliSecs(),renders,fps cube=CreateCube() While Not KeyHit(key_escape) TurnEntity cube,0,0,1 MoveEntity cube,0.1,0,0 RenderWorld renders:+1 If MilliSecs()-old_ms>=1000 old_ms=MilliSecs(); fps=renders; renders=0 EndIf 'addmore stuff to the list For Local n:Int = 0 To 49 Local r:Int=Rand(0,3) If r=0 list.AddLast New glsprite.Create(EntityX(cube), EntityY(cube), tex, Rand(0, 359), 0.3) If r=1 list.Addlast New glsprite.Create(EntityX(cube), EntityY(cube), tex, Rand(0, 359), 0.3,0.5,0) glsprite(list.last()).scale(2.5,2.5) EndIf If r=2 list.AddLast New glsprite.Create(EntityX(cube), EntityY(cube), tex, Rand(0, 359), 0.3,0,0.5) If r=3 list.AddLast New glsprite.Create(EntityX(cube), EntityY(cube), tex, Rand(0, 359), 0.3,0.5,0.5) Next 'enable/disable stuff glenable(GL_COLOR_MATERIAL) glShadeModel(GL_SMOOTH); glDisable(GL_DEPTH_TEST); glEnable(GL_BLEND); glBlendFunc(GL_SRC_ALPHA,GL_ONE); glEnable(GL_TEXTURE_2D); 'update sprites Local currenttexture:Int Local count:Int=0 glbegin(gl_quads) For Local g:glsprite=EachIn list If g.update(currenttexture)=True Then list.remove g count:+1 currenttexture=g.tex Next glend() beginmax2d() DrawText"FPS: "+String(fps) ,10,10 DrawText "Sprites: " + String(list.count()), 10, 20 endmax2d() Flip If KeyHit (key_space) Then SavePixmapPNG(GrabPixmap(0,0,640,480),"savedpic.png",0) Wend Type glsprite Field tex:Int Field x:Float,y:Float,z:Float=0 Field angle:Float=0 Field life:Float=1.0 Field rot:Float=Rnd(-2,2) Field xscale:Float=1,yscale:Float=1 Field r:Int=255,g:Int=255,b:Int=255 Field speed:Float Field texoffsetx:Float=0,texoffsety:Float=0 Field texwidth:Float=0.5,texheight:Float=0.5 Function Create:glsprite(inx:Float,iny:Float,intex:Int,angle:Float,speed:Float,tox:Float=0,toy:Float=0) Local n:glsprite=New glsprite n.x=inx n.y=iny n.tex=intex n.angle=angle n.speed=speed n.texoffsetx=tox n.texoffsety=toy Return n EndFunction Method scale(sx:Float,sy:Float) xscale=sx;yscale=sy EndMethod Method update:Int(currenttexture) life:-0.01 x:+speed*Cos(angle) y:+speed*Sin(angle) glcolor4f(r,g,b,life) If currenttexture<>tex glend() glbindtexture(GL_TEXTURE_2D,tex) glbegin(gl_quads) EndIf 'bottom right glTexCoord2d(texoffsetx+texwidth, texoffsety+texheight) glvertex3f(x+((1*xscale)*Cos(angle+135)),y+((1*yscale)*Sin(angle+135)),z) 'bottomleft glTexCoord2d(texoffsetx,texoffsety+texheight) glvertex3f(x+((1*xscale)*Cos(angle+225)),y+((1*yscale)*Sin(angle+225)),z) 'topleft glTexCoord2d(texoffsetx, texoffsety) glvertex3f(x+((1*xscale)*Cos(angle+315)),y+((1*yscale)*Sin(angle+315)),z) 'topright glTexCoord2d(texoffsetx+texwidth, texoffsety) glvertex3f(x+((1*xscale)*Cos(angle+45)),y+((1*yscale)*Sin(angle+45)),z) If life<0 Then Return True Return False EndMethod End Type Function AdjustTexSize(width:Int Var, Height:Int Var) Function Pow2Size:Int(N:Int) Local Size:Int Size = 1 While Size < N Size = Size Shl 1 Wend Return Size End Function Width = Pow2Size(Width) Height = Pow2Size(Height) End Function Function TexFromPixmap:Int(pixmap:TPixmap, mipmap:Int = True) If pixmap.format<>PF_RGBA8888 pixmap=pixmap.Convert( PF_RGBA8888 ) Local width:Int=pixmap.width,height:Int=pixmap.height AdjustTexSize width,height If width<>pixmap.width Or height<>pixmap.height pixmap=ResizePixmap( pixmap,width,height ) Local old_name:Int,old_row_len:Int glGetIntegerv GL_TEXTURE_BINDING_2D,Varptr old_name glGetIntegerv GL_UNPACK_ROW_LENGTH,Varptr old_row_len Local name:Int glGenTextures 1,Varptr name glBindtexture GL_TEXTURE_2D,name Local mip_level:Int Repeat glPixelStorei GL_UNPACK_ROW_LENGTH,pixmap.pitch/BytesPerPixel[pixmap.format] glTexImage2D GL_TEXTURE_2D,mip_level,GL_RGBA8,width,height,0,GL_RGBA,GL_UNSIGNED_BYTE,pixmap.pixels If Not mipmap Exit If width=1 And height=1 Exit If width>1 width:/2 If height>1 height:/2 pixmap=ResizePixmap( pixmap,width,height ) mip_level:+1 Forever glBindTexture GL_TEXTURE_2D,old_name glPixelStorei GL_UNPACK_ROW_LENGTH,old_row_len Return name End Function you'll also need this image: http://c-knight.madasafish.com/testtex.bmp I hope someone can help with this, i'm not exactly an expert in OpenGL, but i'd really like to be able to use this code in my game. Cheers Charlie

jkrankie (Posted 2009) [#2]

Further investigation - I'm pretty sure it's a blending/masking issue. I switched to .png images and the problem seems to have vanished. Super! Cheers Charlie