Can't draw Circle without drawing another Picture

[jxv]

I'm guessing some state isn't being set with the circle geometry opposed to the pictures with triangle or bezier curve geometries.

Current workaround is to draw a black square at the beginning of every frame.

import qualified SDL as SDL
import Control.Arrow
import Linear hiding (angle)
import Control.Monad.Except (runExceptT)
import System.Exit (exitSuccess)
import Control.Monad (forever, when)
import Control.Concurrent (threadDelay)

import Gelatin
import Gelatin.SDL2 hiding (rotate)

blackSquarePic :: ColorPicture ()
blackSquarePic = setGeometry $ triangles tris
  where tris = do tri (0, black) (V2 100 0, black) (100, black)
                  tri (0, black) (V2 0 100, black) (100, black)

circlePic :: ColorPicture ()
circlePic = do
  setStroke [StrokeWidth 3, StrokeFeather 1]
  setGeometry $ line $ mapVertices (\v -> (v, white)) (arc 10 10 0 (2 * pi))

isQuit :: SDL.Event -> Bool
isQuit (SDL.Event _ payload) = isKeyQ payload || payload == SDL.QuitEvent
  where
    isKeyQ (SDL.KeyboardEvent (SDL.KeyboardEventData _ _ _ (SDL.Keysym _ SDL.KeycodeQ _))) = True
    isKeyQ _ = False

main :: IO ()
main = do
  runExceptT (startupSDL2Backends 1000 600 "Black Square for Circle" True) >>= \case
    Left _ -> return ()
    Right backends@(SDL2Backends glv2v4 _glv2v2) -> do
      (_, circleRender) <- compilePicture glv2v4 circlePic
      (_, blackSquareRender) <- compilePicture glv2v4 blackSquarePic
      forever $ do
        threadDelay 1
        events <- getEvents glv2v4
        when (any isQuit events) exitSuccess
        clearWindow glv2v4
        snd blackSquareRender [] -- Toggle blackSquareRender to draw circle (or not!)
        snd circleRender [move 300 300]
        updateWindow glv2v4

[schell]

Yeah, that's funky - thanks for the report! I'll investigate and push a fix ASAP.

[schell]

Nice catch @jxv - turns out the color line renderer was not properly setting the projection matrix. Should be fixed on master.