Draw shadows in a framebuffer object

src/Picture/Preload.hs

@@ -113,6 +113,7 @@ setupFramebuffer = do
     bindRenderbuffer Renderbuffer $= fboRBO
     renderbufferStorage Renderbuffer Depth24Stencil8 (RenderbufferSize 800 600)
                                     -- not sure if the stencil is needed
+    framebufferRenderbuffer Framebuffer DepthStencilAttachment Renderbuffer fboRBO
 
     fboStatus <- framebufferStatus Framebuffer
     putStrLn $ show fboStatus

src/Picture/Render.hs

@@ -51,9 +51,11 @@ renderPicture' pdata rot zoom (tranx,trany) (winx,winy) wallPoints lightPoints p
 -- draw lightmap
 
     bindFramebuffer Framebuffer $= (_spareFBO pdata)
+    depthFunc $= Just Less
     clearColor $= Color4 0 0.5 0 1
     clearDepth $= (200)
     clear [ColorBuffer]
+--    depthMask $= Enabled
 
     nWalls <- F.foldM (pokeShader (_wallShadowShader pdata)) wallPoints
     bindShaderBuffers [_wallShadowShader pdata] [nWalls]