Add wall drawing capability (for shadows)

src/Picture/Render.hs

@@ -247,8 +247,81 @@ threePtrsVAO :: VAO -> (Ptr Float, Ptr Float,Ptr Float)
 threePtrsVAO vao = case (\(_,ps,_) -> ps) $ unzip3 $ _vaoBufferTargets vao of
     (a:b:c:_) -> (a,b,c)
 
-renderPicture' :: PreloadData -> Float -> Float -> (Float,Float) -> (Float,Float) -> Picture -> IO ()
-renderPicture' pdata rot zoom (tranx,trany) (winx,winy) pic = do
+renderPicture' :: PreloadData -> Float -> Float -> (Float,Float) -> (Float,Float) ->
+                    [(Point2,Point2,Point2,Point2)] -> Picture -> IO ()
+renderPicture' pdata rot zoom (tranx,trany) (winx,winy) wallPoints pic = do
+    let firstIndex = 0
+
+    (nTriVs,nTextVs,numCircVs,nLineVs,nArcVs) 
+--        <- F.foldM (theFold (_ptrPosVBO pdata, _ptrColVBO pdata)  
+        <- F.foldM (theFold (twoPtrsVAO $ _triVAO pdata)  
+                            (threePtrsVAO $ _textVAO pdata)
+                            (threePtrsVAO $ _circVAO pdata)
+                            (twoPtrsVAO $ _lineVAO pdata)
+                            (threePtrsVAO $ _arcVAO pdata)
+                   ) $ picToFTree pic
+
+    depthFunc $= Just Less
+
+    currentProgram $= Just (_wallShadowShader pdata)
+    bindVertexArrayObject $= Just (_vao $ _wallVAO pdata)
+    let wallPtr = (\(_,x,_) -> x) $ head $ _vaoBufferTargets $ _wallVAO pdata
+        wallPtr2 = (\(_,x,_) -> x) $ (_vaoBufferTargets $ _wallVAO pdata) !! 1
+        foldWalls n ((x,y),(z,w),(a,b),(c,d)) = do
+                pokeFourOff wallPtr  n (x,y,z,w)
+                pokeFourOff wallPtr2 n (a,b,c,d)
+                return $ n+1
+    nWalls <- foldM foldWalls 0 wallPoints 
+    bindArrayBuffers (length wallPoints) $ _vaoBufferTargets $ _wallVAO pdata
+    drawArrays Points (fromIntegral 0) (fromIntegral $ length wallPoints)
+    
+    currentProgram $= Just (_backShader pdata)
+    bindVertexArrayObject $= Just (_vao $ _backVAO pdata)
+    let backPtr = (\(_,x,_) -> x) $ head $ _vaoBufferTargets $ _backVAO pdata
+        backPtr2 = (\(_,x,_) -> x) $ (_vaoBufferTargets $ _backVAO pdata) !! 1
+    pokeFourOff backPtr 0 (tranx,trany,rot,zoom)
+    pokeTwoOff backPtr2 0  (winx,winy)
+    bindArrayBuffers 1 $ _vaoBufferTargets $ _backVAO pdata
+    textureBinding Texture2D $= Just (_textures pdata !! 1)
+    drawArrays Points (fromIntegral 0) (fromIntegral 1)
+    
+
+-- draw triangles
+    currentProgram $= Just (_basicShader pdata)
+    bindVertexArrayObject $= Just (_vao $ _triVAO pdata)
+    bindArrayBuffers nTriVs $ _vaoBufferTargets $ _triVAO pdata
+    drawArrays Triangles (fromIntegral firstIndex) (fromIntegral $ nTriVs)
+-- draw lines, don't need to change the program or vaos, just need to bind the
+-- vbos and draw
+    bindVertexArrayObject $= Just (_vao $ _lineVAO pdata)
+    bindArrayBuffers nTriVs $ _vaoBufferTargets $ _lineVAO pdata
+    drawArrays Lines (fromIntegral firstIndex) (fromIntegral $ nLineVs)
+-- draw circles
+    currentProgram $= Just (_circShader pdata)
+    uniform (_uniWinSize pdata) $= Vector2 winx winy
+    uniform (_csZoomUni pdata)  $= zoom
+    bindVertexArrayObject $= Just (_vao $ _circVAO pdata)
+    bindArrayBuffers numCircVs $ _vaoBufferTargets $ _circVAO pdata
+    drawArrays Points (fromIntegral firstIndex) (fromIntegral $ numCircVs)
+-- draw arcs
+    currentProgram $= Just (_arcShader pdata)
+    uniform (_asWinUni pdata) $= Vector2 winx winy
+    uniform (_asZoomUni pdata)  $= zoom
+    bindVertexArrayObject $= Just (_vao $ _arcVAO pdata)
+    bindArrayBuffers nArcVs $ _vaoBufferTargets $ _arcVAO pdata
+    drawArrays Points (fromIntegral firstIndex) (fromIntegral $ nArcVs)
+-- draw text
+    currentProgram $= Just (_textShader pdata)
+    bindVertexArrayObject $= Just (_vao $ _textVAO pdata)
+    bindArrayBuffers nTextVs $ _vaoBufferTargets $ _textVAO pdata
+    textureBinding Texture2D $= Just (_textures pdata !! 0)
+    drawArrays Points (fromIntegral firstIndex) (fromIntegral $ nTextVs)
+
+bufferOffset :: Integral a => a -> Ptr b
+bufferOffset = plusPtr nullPtr . fromIntegral
+
+renderPicture :: PreloadData -> Float -> Float -> (Float,Float) -> (Float,Float) -> Picture -> IO ()
+renderPicture pdata rot zoom (tranx,trany) (winx,winy) pic = do
     let firstIndex = 0
 
     (nTriVs,nTextVs,numCircVs,nLineVs,nArcVs) 
@@ -303,6 +376,3 @@ renderPicture' pdata rot zoom (tranx,trany) (winx,winy) pic = do
     bindArrayBuffers nTextVs $ _vaoBufferTargets $ _textVAO pdata
     textureBinding Texture2D $= Just (_textures pdata !! 0)
     drawArrays Points (fromIntegral firstIndex) (fromIntegral $ nTextVs)
-
-bufferOffset :: Integral a => a -> Ptr b
-bufferOffset = plusPtr nullPtr . fromIntegral