Some notes.

1 files changed, 16 insertions, 5 deletions

diff --git a/MaskableStream.hs b/MaskableStream.hs
index c023998..e6628e6 100644
--- a/MaskableStream.hs
+++ b/MaskableStream.hs
@@ -57,6 +57,12 @@ bindTextureCommand tlookup ulookup n = GLBindTexture (inputTypeToTextureTarget $
     uniInputType (GLTypedUniform ty _) = unwitnessType ty
     uniInputType (GLUniform r)         = objectType r
 
+-- One of these:
+--    VertexAttribPointer         -- Array
+--    VertexAttribIPointer        --  streams.
+--    VertexAttribI{1,2,3,4}[u]iv -- constant integer attribute.
+-- Or some number of these in sequence:
+--    VertexAttrib{1,2,3,4}fv -- constant vector or matrix of floats.
 setVertexAttribCommmand :: (t -> Stream Buffer) -> (GLuint, t) -> GLObjectCommand
 setVertexAttribCommmand alookup (i,name) = case alookup name of
     Stream ty (Buffer arrs bo) arrIdx start len -> mkAttrCmd i bo n (arrayTypeToGLType arrType) (intPtrToPtr $! offset)
@@ -107,6 +113,10 @@ drawElementsCommand prim (IndexStream (Buffer arrs bo) arrIdx start idxCount)
     idxType = arrayTypeToGLType arrType
     ptr    = intPtrToPtr $! fromIntegral (arrOffs + start * sizeOfArrayType arrType)
 
+-- Note: all enabled attribute arrays should have the same count.
+-- So an object should select similarly sized streams from 'dStreams' of GPUData.
+-- So the 'mAttributes' map of a Mesh should contain equally sized arrays.
+-- uploadMeshToGPU uses a single Buffer for all of a Mesh's attributes.
 objectDrawStyle :: (GLsizei -> [(GLint,GLsizei)]) -- ^ mask, normally \x -> [(0,x)]
                     -> Object
                     -> Either [(GLint,GLsizei)] (IndexStream Buffer)
@@ -121,11 +131,12 @@ createObjectCommands texUnitMap topUnis obj prg =
     createObjectCommands_ (objectEnvironment texUnitMap topUnis obj (pure . ((,) 0))) prg
 
 data ObjectEnvironment = ObjectEnvironment
-    { envPrim      :: GLenum
-    , envDrawStyle :: Either [(GLint,GLsizei)] (IndexStream Buffer)
-    , tlookup      :: String -> IORef GLint
-    , ulookup      :: String -> GLUniform
-    , alookup      :: String -> Stream Buffer
+    { envPrim      :: GLenum -- GL version of LambdaCube.GL.Primitive
+    , envDrawStyle :: Either [(GLint,GLsizei)]    -- Mask of array attributes (one draw command for pair).
+                             (IndexStream Buffer) -- Indirect P_TriangleStripI or P_TrianglesI indices.
+    , tlookup      :: String -> IORef GLint   -- lookup texture unit
+    , ulookup      :: String -> GLUniform     -- lookup uniform
+    , alookup      :: String -> Stream Buffer -- lookup vertex attribute
     }
 
 objectEnvironment :: Map.Map String (IORef GLint)