Cannot disable depth/color clear for manually created buffer

Scripting Issues
1

I have this setup:

lens = base.cam.node().getLens()

self.mainMask = 1
self.obstructionMask = 2

self.mainBuf = self.makeFBO("main buffer", -3, extra_flags = GraphicsPipe.BFRequireParasite)
self.maincam = base.makeCamera(self.mainBuf, lens=lens)
self.maincam.reparentTo(base.cam)
self.mainTex = Texture()
self.mainBuf.addRenderTexture(self.mainTex, GraphicsOutput.RTMBindOrCopy, GraphicsOutput.RTPColor)

self.backBuf = self.makeFBO("back buffer", -2, extra_flags = GraphicsPipe.BFRequireParasite)
self.backcam = base.makeCamera(self.backBuf, lens=lens, mask=self.obstructionMask)
self.backcam.reparentTo(base.cam)
self.backTex = Texture()
self.backBuf.addRenderTexture(self.backTex, GraphicsOutput.RTMBindOrCopy, GraphicsOutput.RTPColor)

self.frontBuf = self.makeFBO("front buffer", -1, extra_flags = GraphicsPipe.BFRequireParasite)
self.frontcam = base.makeCamera(self.frontBuf, lens=lens, mask=self.obstructionMask)
self.frontcam.reparentTo(base.cam)
self.frontTex = Texture()
self.frontBuf.addRenderTexture(self.frontTex, GraphicsOutput.RTMBindOrCopy, GraphicsOutput.RTPColor)

#self.mainBuf.shareDepthBuffer(self.backBuf)
#self.mainBuf.shareDepthBuffer(self.frontBuf)

# disable default camera
base.cam.node().setActive(False)
base.cam.node().getDisplayRegion(0).setActive(False)

self.mainBuf.setSort(1)
self.backBuf.setSort(2)
self.frontBuf.setSort(3)
base.win.setSort(4)

self.maincam.node().getDisplayRegion(0).setSort(1)
self.backcam.node().getDisplayRegion(0).setSort(2)
self.frontcam.node().getDisplayRegion(0).setSort(3)

# By default, panda usually clears the screen before every
# camera and before every window.  Tell it not to do that.
# Then, tell it specifically when to clear and what to clear.
self.maincam.node().getDisplayRegion(0).disableClears()
self.backcam.node().getDisplayRegion(0).disableClears()
self.frontcam.node().getDisplayRegion(0).disableClears()
base.cam.node().getDisplayRegion(0).disableClears()
base.cam2d.node().getDisplayRegion(0).disableClears()
base.win.disableClears()

base.win.setClearDepthActive(False)
base.win.setClearColorActive(False)
base.cam.node().getDisplayRegion(0).setClearColorActive(False)
base.cam2d.node().getDisplayRegion(0).setClearColorActive(False)
self.backcam.node().getDisplayRegion(0).setClearColorActive(False)
self.backcam.node().getDisplayRegion(0).setClearColor(Vec4(0,0,0,1))
self.backcam.node().getDisplayRegion(0).setClearDepthActive(False)
self.frontcam.node().getDisplayRegion(0).setClearColorActive(False)
self.frontcam.node().getDisplayRegion(0).setClearColor(Vec4(0,0,0,0))
self.frontcam.node().getDisplayRegion(0).setClearDepthActive(False)

# Clear any render attribs on the root node. This is necessary
# because by default, panda assigns some attribs to the root
# node.  These default attribs will override the
# carefully-configured render attribs that we just attached
# to the cameras.  The simplest solution is to just clear
# them all out.
render.setState(RenderState.makeEmpty())

tempnode = NodePath(PandaNode("temp node"))
#tempnode.setTwoSided(True, 100)
tempnode.setAttrib(CullFaceAttrib.make(CullFaceAttrib.MCullCounterClockwise), 100)
self.backcam.node().setInitialState(tempnode.getState())

tempnode = NodePath(PandaNode("temp node"))
#tempnode.setTwoSided(True, 100)
tempnode.setAttrib(CullFaceAttrib.make(CullFaceAttrib.MCullClockwise), 100)
self.frontcam.node().setInitialState(tempnode.getState())

base.setBackgroundColor(Vec4(1,0,0,0))
		
self.accept("v", base.bufferViewer.toggleEnable)
self.accept("V", base.bufferViewer.toggleEnable)
base.bufferViewer.setPosition("llcorner")

def makeFBO(self, name, sort, rgb=1, alpha=1, depth=1, aux=0, extra_flags = 0):
	# This routine creates an offscreen buffer.  All the complicated
	# parameters are basically demanding capabilities from the offscreen
	# buffer - we demand that it be able to render to texture on every
	# bitplane, that it can support aux bitplanes, that it track
	# the size of the host window, that it can render to texture
	# cumulatively, and so forth.
	winprops = WindowProperties()
	props = FrameBufferProperties()
	props.setRgbColor(rgb)
	props.setAlphaBits(alpha)
	props.setDepthBits(depth)
	props.setAuxRgba(aux)
	return base.graphicsEngine.makeOutput(
		base.pipe, name, sort,
		props, winprops,
		#GraphicsPipe.BFSizeTrackHost | GraphicsPipe.BFCanBindEvery | 
		#GraphicsPipe.BFRttCumulative | GraphicsPipe.BFRefuseWindow |
		GraphicsPipe.BFSizeTrackHost | GraphicsPipe.BFRefuseWindow | 
		#GraphicsPipe.BFResizeable | 
		extra_flags,
		base.win.getGsg(), base.win)

When I run the program, buffer viewer shows that all buffers are cleared from any previous renderings. If I disable clear-color, buffers have grey background, otherwise they have the color which I specify in setClearColor.

2

Since your buffers are parasite buffers, they are actually rendered into the main window, and they are inheriting the clear color from that window.

David

3

But why clear is performed at all? I thought I’ve turned clear of every possible buffer off… It seems that disable/deactivate commands are just ignored u_u

4

Ah, I see. But you never disable the clear on the ParasiteBuffers as you create them. The default behavior when you create a new buffer is to enable clear, so each of your ParasiteBuffers still has clear enabled.

David

5

Thanks, now I got it) Seems like I really overlooked this bit of documentation. My deepest apologies ^^