ReferenceError when trying to Cache a GeClipMap

Hello,
I'm trying to create a crude example of caching the Bitmaps/GeClipMaps and I'm running into an error I can't seem to solve. In the code below, self.UpdateBackgroundCache() works, but self.UpdateBoxCache() does not. In this function, I'm creating a GeClipMap, initializing it, drawing a rectangle, and storing the clipmap's BaseBitmap as a property of the GeUserArea. I keep getting the error:

ReferenceError: the object 'c4d.bitmaps.BaseBitmap' is not alive

Can anyone help me understand what is going wrong? Thank you!

import c4d
from c4d import gui,bitmaps

GADGET_ID_GEUSERAREA = 10000

def drawColorBitmap(w,h,r,g,b):
    r = int(r * 255)
    g = int(g * 255)
    b = int(b * 255)
    bmp = bitmaps.BaseBitmap()
    bmp.Init(w, h, 24)
    for wPixel in range(w):
        for hPixel in range(h):
            bmp.SetPixel(wPixel, hPixel, r, g, b)
    return bmp

class MyUserArea(c4d.gui.GeUserArea):
    def __init__(self):
        self.boxX = 50
        self.boxY = 50
        self.boxWidth = 50
        self.boxHeight = 50
        self.boxAngle = 0
        self.boxOpacity = 1.0
        self.bgCache = None
        self.boxCache = None

    def UpdateBackgroundCache(self,x2,y2):
        self.bgCache = drawColorBitmap(x2,y2,0.35,0.35,0.35)

    def UpdateBoxCache(self):
        rMap = c4d.bitmaps.GeClipMap()
        rMap.Init(self.boxWidth, self.boxHeight)
        rMap.BeginDraw()
        rMap.SetDrawMode(c4d.GE_CM_DRAWMODE_BLEND,
            c4d.GE_CM_SRC_MAX_OPACITY)
        rMap.SetColor(255,0,0,255)
        rMap.FillRect(0,0,50,self.boxHeight)
        rMap.EndDraw()
        self.boxCache = rMap.GetBitmap()        

    def GetMinSize(self):
        return 300,150

    def UpdateCache(self):
        #Cache Background
        if self.bgCache == None:
            self.UpdateBackgroundCache(self.GetWidth(),self.GetHeight())

        #Cache Red Box
        if self.boxCache == None:
            self.UpdateBoxCache()

        #Blit Red Box with Background
        clipMap = bitmaps.GeClipMap()
        clipMap.InitWithBitmap(self.bgCache, None)
        clipMap.BeginDraw()
        clipMap.SetDrawMode(c4d.GE_CM_DRAWMODE_BLEND,
            c4d.GE_CM_SRC_MAX_OPACITY)

        rectMap = bitmaps.GeClipMap()
        rectMap.InitWithBitmap(self.boxCache, None)

        clipMap.Blit(self.boxX, self.boxY,
            rectMap, 0, 0, self.boxWidth, self.boxHeight,
            rop = c4d.GE_CM_BLIT_COL)

        clipMap.EndDraw()
        bmp = clipMap.GetBitmap()
        return bmp

    def DrawMsg(self, x1, y1, x2, y2, msg):
        cache = self.UpdateCache()
        self.DrawBitmap(cache, x1, y1, x2, y2, 0, 0, 300, 150, c4d.BMP_NORMAL | c4d.BMP_ALLOWALPHA)

class ExampleDialog(c4d.gui.GeDialog):
    geUserArea = MyUserArea()

    def CreateLayout(self):
        self.SetTitle("ClipMap")
        self.AddUserArea(GADGET_ID_GEUSERAREA, c4d.BFH_CENTER | c4d.BFH_SCALE | c4d.BFV_CENTER | c4d.BFV_SCALE, 300, 150)
        self.AttachUserArea(self.geUserArea, GADGET_ID_GEUSERAREA)
        return True

def main():
    global dlg
    dlg = ExampleDialog()
    dlg.Open(c4d.DLG_TYPE_ASYNC, defaultw=400, defaulth=250, xpos=-2, ypos=-2)

if __name__=='__main__':
    main()

ferdinand

Hi @blastframe,

thank you for reaching out to us. The error ReferenceError: the object 'xyz' is not alive means that something has deallocated the object you are trying to reference. This happens because you have two competing memory management systems, one provided by Python, its gc, and one provided by Cinema's C++ API. In this case the method GeClipMap.GetBitmap() (Link to C++ Doc) only does return a pointer, i.e. an object that is owned by the GeClipMap. To avoid the error, you have either to avoid the GeClipMap being garbage collected or clone the bitmap so that you have full ownership. I "fixed" your code by just plastering in two .GetClone().

Cheers,
Ferdinand

import c4d
from c4d import gui,bitmaps

GADGET_ID_GEUSERAREA = 10000
FOO = None
def drawColorBitmap(w,h,r,g,b):
    r = int(r * 255)
    g = int(g * 255)
    b = int(b * 255)
    bmp = bitmaps.BaseBitmap()
    bmp.Init(w, h, 24)
    for wPixel in range(w):
        for hPixel in range(h):
            bmp.SetPixel(wPixel, hPixel, r, g, b)
    return bmp

class MyUserArea(c4d.gui.GeUserArea):
    def __init__(self):
        self.boxX = 50
        self.boxY = 50
        self.boxWidth = 50
        self.boxHeight = 50
        self.boxAngle = 0
        self.boxOpacity = 1.0
        self.bgCache = None
        self.boxCache = None

    def UpdateBackgroundCache(self,x2,y2):
        self.bgCache = drawColorBitmap(x2,y2,0.35,0.35,0.35)

    def UpdateBoxCache(self):
        rMap = c4d.bitmaps.GeClipMap()
        rMap.Init(self.boxWidth, self.boxHeight)
        rMap.BeginDraw()
        rMap.SetDrawMode(c4d.GE_CM_DRAWMODE_BLEND,
            c4d.GE_CM_SRC_MAX_OPACITY)
        rMap.SetColor(255,0,0,255)
        rMap.FillRect(0,0,50,self.boxHeight)
        rMap.EndDraw()
        # The bitmap returned by GeClipMap.GetBitmap() is owned by the 
        # GeClipMap. Leaving the scope of this function will free the
        # GeClipMap and with it the attached BaseBitmap.
        bitmap = rMap.GetBitmap()
        # Either clone the bitmap or also reference the GeClipMap so that
        # it won't be deallocated on exit.
        self.boxCache = bitmap.GetClone()

    def GetMinSize(self):
        return 300,150

    def UpdateCache(self):
        #Cache Background
        if self.bgCache == None:
            self.UpdateBackgroundCache(self.GetWidth(),self.GetHeight())

        #Cache Red Box
        if self.boxCache == None:
            self.UpdateBoxCache()

        #Blit Red Box with Background
        clipMap = bitmaps.GeClipMap()
        clipMap.InitWithBitmap(self.bgCache, None)
        clipMap.BeginDraw()
        clipMap.SetDrawMode(c4d.GE_CM_DRAWMODE_BLEND,
            c4d.GE_CM_SRC_MAX_OPACITY)

        rectMap = bitmaps.GeClipMap()
        rectMap.InitWithBitmap(self.boxCache, None)

        clipMap.Blit(self.boxX, self.boxY,
            rectMap, 0, 0, self.boxWidth, self.boxHeight,
            rop = c4d.GE_CM_BLIT_COL)

        clipMap.EndDraw()
        # The same thing applies here.
        bmp = clipMap.GetBitmap()
        return bmp.GetClone()

    def DrawMsg(self, x1, y1, x2, y2, msg):
        cache = self.UpdateCache()
        self.DrawBitmap(cache, x1, y1, x2, y2, 0, 0, 300, 150, c4d.BMP_NORMAL | c4d.BMP_ALLOWALPHA)

class ExampleDialog(c4d.gui.GeDialog):
    geUserArea = MyUserArea()

    def CreateLayout(self):
        self.SetTitle("ClipMap")
        self.AddUserArea(GADGET_ID_GEUSERAREA, c4d.BFH_CENTER | c4d.BFH_SCALE | c4d.BFV_CENTER | c4d.BFV_SCALE, 300, 150)
        self.AttachUserArea(self.geUserArea, GADGET_ID_GEUSERAREA)
        return True

def main():
    global dlg
    dlg = ExampleDialog()
    dlg.Open(c4d.DLG_TYPE_ASYNC, defaultw=400, defaulth=250, xpos=-2, ypos=-2)

if __name__=='__main__':
    main()

@zipit Thank you very much, Ferdinand. This helped me a lot!