freeImage/drawQuad corruption issues

Nisse5

It seems like freeImage() of no longer used images can result in corruption, at least in combo with drawQuad(). I have not been able to figure out exactly why.

This code creates a corrupted image, if the duplication is done twice. It seems like "img1" needs to be present when img3 is created, which seems very odd to me.

w = 200
h = 100

function makeResizedImageCopy(oldimg, oldheight, newheight)
   newimg = createImage(w, newheight, image_rgba)
   setDrawTarget(newimg)
   topleft = {0, 0}
   topright = {w, 0}
   bottomright = {w, newheight}
   bottomleft = {0, newheight}
   drawQuad(oldimg, {0, 0, w, oldheight}, [topleft, toplight, bottomright, bottomleft], white)
   setDrawTarget(framebuffer)
   freeImage(oldimg)  // This is the problematic row!
return newimg

// Create a yellow square
img1 = CreateImage(w, h, image_rgba)
setDrawTarget(img1)
clear(yellow)
setDrawTarget(framebuffer)

// Shrink copies in 2 steps
img2 = makeResizedImageCopy(img1, 100, 80)
img3 = makeResizedImageCopy(img2, 80, 60)

// Display the last (corrupted) image
loop
   clear()
   drawImage(img3, 10, 10)
   update()
repeat

If I remove freeImage() from the function and do something like this, it'll work:

// Shrink copies in 2 steps
img2 = makeResizedImageCopy(img1, 100, 80)
img3 = makeResizedImageCopy(img2, 80, 60)
freeImage(img1)
freeImage(img2)

If I remove freeImage() from the function but do like this, it'll NOT work:

// Shrink copies in 2 steps
img2 = makeResizedImageCopy(img1, 100, 80)
freeImage(img1)
img3 = makeResizedImageCopy(img2, 80, 60)
freeImage(img2)