CreateGraphics without a backbuffer?
BlitzMax Forums/BlitzMax Programming/CreateGraphics without a backbuffer?
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| In the Help-doc it states: "Graphics created with the GRAPHICS_BACKBUFFER flag must be 'flipped' after you have finished rendering using Flip." Does this mean one can create a graphics without a BackBuffer? And if so, then how? And would the drawing to such a graphics be done directly to the frontbuffer? i.o.w. Is there any practicallity to set the GraphicsFlags without GRAPHICS_BACKBUFFER. |
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| No it would be the worst idea you could have. As Max2D is 3D always you would create serious problems by not using double buffering. (most likely the well known flickering) |
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| I don't need nor want Double Buffering. I want to change very small portions of the screen each frame. So I can take care of the "cleanup" myself. And for speed reasons I don't want to "reDraw" everything. I could do: ----------- flip 0 draw something small flip ----------- But,(as XLSIOR stated) you can't actually *count* on the backbuffer not getting cleared by the driver. So I thougt by being able to draw directly to a frontbuffer I could avoid this "potential?" problem. |
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Take a look at this:SetGraphicsDriver GLMax2DDriver(),0 Graphics( 800, 600, 32, 60, 0) HideMouse() MoveMouse GraphicsWidth()/2, GraphicsHeight() / 2 Local OldMouseX:Float = MouseX() Local OldMouseY:Float = MouseY() Local newmousex:Int Local newMousey:Int Local t:Int, temp:Int Local Before:Int=MilliSecs() Local RightNow:Int Local fps:Int Local AFPS:Int,ACount:Int=0 Local Effect=0 Cls For t=0 To 100 SetColor Rand(0,255),Rand(0,255),Rand(0,255) DrawRect 20+t*4,20+t*4,100,100 SetColor 255,255,255 Plot t,t DrawText "test",t*4,t*4 Next While Not KeyDown( KEY_ESCAPE) If KeyDown(KEY_SPACE) Then effect=1-effect SetColor 0,0,0 DrawRect OldMouseX ,oldMouseY,20,20 'cleaning up after the mouse SetColor 255,255,255 newmousex=Int(MouseX()) newMousey=Int(MouseY()) SetColor 255,255,255 DrawRect NewMouseX ,NewMouseY,20,20 SetColor 155,25,2 DrawOval newMouseX ,newMouseY,20,20 If effect For t=0 To 2000 SetColor Rand(0,255),Rand(0,255),Rand(0,255) Plot Rand(40,600),Rand(40,500) Next Else For t=0 To 2000 SetColor Rand(0,255),Rand(0,255),Rand(0,255) DrawRect newMouseX+30+(t/10) ,newMouseY+30,20,20 Next EndIf OldMouseX =newMouseX OldMouseY =newMouseY RightNow=MilliSecs() temp=RightNow-Before If temp<1 Then temp=1 FPS=1000/temp Before=RightNow ACount=ACount+1 AFPS=(AFPS+FPS)/2 If ACount=100 ACount=0 SetColor 0,0,0 DrawRect 20 ,20,40,20 SetColor 255,255,255 DrawText afps,20,20 EndIf Flip 0 'Has probably absolute no meaning(does Nothing?) Wend EndGraphics Perhaps it's dirty and not save? because I have no knowledge of GraphicsDrivers whatsoever. But it "seems" to work. |
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| The easy answer is yes you do not have to have a backbuffer. Use: SetGraphicsDriver(WhateverGraphicsDriver(),0) Make sure you specify 0 (or whatever combination of actual buffers that you want to be the default), and you will get a display without a backbuffer. Everything you draw will draw straight to the visible buffer as soon as the graphics card decides to flush its list of things to do. Typically that means right away. There ARE some benefits in some situations to using a single-buffered display system. For one, it lets you keep the same previous contents of the front buffer so you can do things like dirty rectangles and updating the custom mouse pointer without having to redraw and flip the entire display. Yes it MIGHT be prone to tearing because you are drawing to the same buffer that the video scan is reading from to create visible pixels on the screen, and in most cases it is very likely you WILL get some tearing, and for `slower` drawing routines you may see the progress of the screen being drawn in whatever order you draw your objects. But this doesn't mean you should discard the whole idea. It can be useful for certain kinds of applications/game engines. So just set the default in the driver to not include GRAPHICS_BACKBUFFER and you're all set. |
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| Now, that is exactly what I wanted to hear :) Thanks A.D. This will speed things up. |
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