Reogranise drawing in main

src/Picture/Render.hs

@@ -1,9 +1,9 @@
 --{-# LANGUAGE Strict #-}
 {-# LANGUAGE DeriveFoldable, StandaloneDeriving #-}
 module Picture.Render
-    ( renderPicture'
-    , renderFoldable
+    ( module Picture.Render
     , picToLTree
+    , perspectiveMatrix 
     )
     where
 
@@ -114,19 +114,27 @@ createLightMap pdata rot zoom (tranx,trany) (winx,winy) wallPoints lightPoints
                     (viewFromx,viewFromy) pmat = do
 
     bindFramebuffer Framebuffer $= (_spareFBO pdata)
-    clearColor $= Color4 0 0.5 0 1
-    depthFunc $= Just Less
+
+-- clear buffer to full alpha and furthest depth
+    clearColor $= Color4 0 0 0 1
     clearDepth $= 1
     clear [ColorBuffer,DepthBuffer]
 
+    depthFunc $= Just Less
+
+-- store wall and light positions into buffer
     nWallLights <- F.foldM (pokeShader $ _wallLightShader pdata) wallPoints
     bindShaderBuffers [_wallLightShader pdata] [nWallLights]
+    nWalls <- F.foldM (pokeShader $ _wallShadowShader pdata) wallPoints
+    bindShaderBuffers [_wallShadowShader pdata] [nWalls]
+
+-- set uniforms for shader that draws lights
     currentProgram $= Just (_shaderProgram $ _wallLightShader pdata)
     uniform ( (fromJust $ _shaderCustomUnis $ _wallLightShader pdata) !! 1)
             $= pmat
 
-    nWalls <- F.foldM (pokeShader $ _wallShadowShader pdata) wallPoints
-    bindShaderBuffers [_wallShadowShader pdata] [nWalls]
+-- draw walls from your point of view in order to set z buffer
+    colorMask $= (Color4 Disabled Disabled Disabled Disabled)
 
     let (tx,ty) = (tranx,trany) -.- (viewFromx,viewFromy)
 
@@ -140,41 +148,44 @@ createLightMap pdata rot zoom (tranx,trany) (winx,winy) wallPoints lightPoints
     cullFace $= Just Back
     drawShader (_wallShadowShader pdata) nWalls
 
+-- for each of the lights: 
+-- stencil out the walls from this lights point of view
+-- draw fading lightmap circles on the floor
+-- draw fading lightmaps on the walls
     depthMask $= Disabled
     blendFunc $= (Zero, OneMinusSrcAlpha)
---    blendFuncSeparate    $= ((Zero,Zero),(Zero, OneMinusSrcAlpha))
     stencilTest $= Enabled
     forM_ lightPoints $ \(x,y,r,lum) -> do
---        depthFunc $= Just Less
-        colorMask $= (Color4 Disabled Disabled Disabled Disabled)
-        clear [StencilBuffer]
-        cullFace $= Just Back
---        stencilOp $= (OpKeep,OpKeep,OpReplace)
-        stencilOp $= (OpKeep,OpKeep,OpIncr)
-        stencilFunc $= (Always, 0, 255)
--- currentProgram does get called twice: here and inside drawShader below
-        currentProgram $= Just (_shaderProgram $ _wallShadowShader pdata)
-        uniform (head $ fromJust $ _shaderCustomUnis $ _wallShadowShader pdata)
-            $= Vector2 x y
---        blendFunc $= (Zero,One)
-        drawShader (_wallShadowShader pdata) nWalls
 
-        cullFace $= Just Front
-        stencilOp $= (OpKeep,OpKeep,OpDecr)
-        drawShader (_wallShadowShader pdata) nWalls
-
-        cullFace $= Nothing
-        
-        colorMask $= (Color4 Enabled Enabled Enabled Enabled)
+-- bind buffer for floor light circle
         let lightPtr = (\(_,ptr,_) -> ptr) $ head 
                             $ _vaoBufferTargets $ _shaderVAO $ _lightSourceShader pdata
             (x',y') = zTran $ rotateV (0 - rot) $ (x,y) -.- (tranx,trany)
             zTran (a,b) = (a*2*zoom / winx, b*2*zoom / winy)
         pokeFourOff lightPtr 0 (x',y',r,lum)
+
+-- stencil out walls
+        colorMask $= (Color4 Disabled Disabled Disabled Disabled)
+        clear [StencilBuffer]
+        cullFace $= Just Back
+        stencilOp $= (OpKeep,OpKeep,OpIncr)
+        stencilFunc $= (Always, 0, 255)
+        currentProgram $= Just (_shaderProgram $ _wallShadowShader pdata)
+        uniform (head $ fromJust $ _shaderCustomUnis $ _wallShadowShader pdata)
+            $= Vector2 x y
+        drawShader (_wallShadowShader pdata) nWalls
+        cullFace $= Just Front
+        stencilOp $= (OpKeep,OpKeep,OpDecr)
+        drawShader (_wallShadowShader pdata) nWalls
+
+-- draw floor light circles
+        cullFace $= Nothing
+        colorMask $= (Color4 Disabled Disabled Disabled Enabled)
         bindShaderBuffers [_lightSourceShader pdata] [1]
         stencilFunc $= (Equal, 0, 255)
         drawShader (_lightSourceShader pdata) 1
 
+-- draw wall light "circles"
         currentProgram $= Just (_shaderProgram $ _wallLightShader pdata)
         uniform (head $ fromJust $ _shaderCustomUnis $ _wallLightShader pdata)
                 $= Vector2 x y  
@@ -204,8 +215,7 @@ renderBackground pdata rot zoom (tranx,trany) (winx,winy) = do
     depthFunc $= Just Less
 
 -- set drawing for on top
-    blendFuncSeparate    $= ((SrcAlphaSaturate, OneMinusSrcAlpha), (Zero,One))
-    clear [DepthBuffer]
+    --blendFuncSeparate    $= ((SrcAlphaSaturate, OneMinusSrcAlpha), (Zero,One))
 
 -- draw background
     bindArrayBuffers 1 $ _vaoBufferTargets $ _shaderVAO $ _backgroundShader pdata