diff --git a/Graphics/GL/Low.hs b/Graphics/GL/Low.hs --- a/Graphics/GL/Low.hs +++ b/Graphics/GL/Low.hs @@ -1,8 +1,6 @@ module Graphics.GL.Low ( - -- * In a Nutshell - -- - -- ** Overview + -- * Overview -- | OpenGL is a graphics rendering interface. This library exposes a vastly -- simplified subset of OpenGL that is hopefully still complete enough for -- many purposes, such as following tutorials, making simple games, and @@ -19,6 +17,105 @@ -- This library uses the `gl' package for raw bindings to OpenGL and the -- `linear' package for matrices. + -- * Example + -- + -- | The hello world program shows a white triangle on a black background. + -- It uses the packages `GLFW-b' and `monad-loops'. Note that it forces a + -- 3.2 core profile when setting up the context through GLFW. + -- + -- @ + -- module Main where + -- + -- import Control.Monad.Loops (whileM_) + -- import Data.Functor ((\<$\>)) + -- import qualified Data.Vector.Storable as V + -- + -- import qualified Graphics.UI.GLFW as GLFW + -- import Graphics.GL.Low + -- + -- -- GLFW will be the shell of the demo + -- main = do + -- GLFW.init + -- GLFW.windowHint (GLFW.WindowHint'ContextVersionMajor 3) + -- GLFW.windowHint (GLFW.WindowHint'ContextVersionMinor 2) + -- GLFW.windowHint (GLFW.WindowHint'OpenGLForwardCompat True) + -- GLFW.windowHint (GLFW.WindowHint'OpenGLProfile GLFW.OpenGLProfile'Core) + -- mwin <- GLFW.createWindow 640 480 \"Demo\" Nothing Nothing + -- case mwin of + -- Nothing -> putStrLn "createWindow failed" + -- Just win -> do + -- GLFW.makeContextCurrent (Just win) + -- GLFW.swapInterval 1 + -- (vao, prog) <- setup -- load and configure objects + -- whileM_ (not \<$\> GLFW.windowShouldClose win) $ do + -- GLFW.pollEvents + -- draw vao prog -- render + -- GLFW.swapBuffers win + -- + -- setup = do + -- -- establish a VAO + -- vao <- newVAO + -- bindVAO vao + -- -- load shader program + -- vsource <- readFile "hello.vert" + -- fsource <- readFile "hello.frag" + -- prog <- newProgram vsource fsource + -- useProgram prog + -- -- load vertex data: three 2D vertex positions + -- let blob = V.fromList + -- [ -0.5, -0.5 + -- , 0, 0.5 + -- , 0.5, -0.5 ] :: V.Vector Float + -- vbo <- newVBO blob StaticDraw + -- bindVBO vbo + -- -- connect program to vertex data via the VAO + -- setVertexAttributeLayout [Attrib "position" 2 VFloat] + -- return (vao, prog) + -- + -- draw vao prog = do + -- clearColorBuffer (0,0,0) + -- bindVAO vao + -- useProgram prog + -- drawTriangles 3 + -- @ + -- + -- The vertex shader file looks like + -- + -- @ + -- #version 150 + -- + -- in vec2 position; + -- + -- void main() + -- { + -- gl_Position = vec4(position, 0.0, 1.0); + -- } + -- @ + -- + -- And the corresponding fragment shader file + -- + -- @ + -- #version 150 + -- + -- out vec4 outColor; + -- + -- void main() + -- { + -- outColor = vec4(1.0, 1.0, 1.0, 1.0); + -- } + -- @ + -- + -- And the output should look like + -- + -- <> + + -- * OpenGL API Basically + -- + -- | + -- for OpenGL 3.2 is actually quite readable and is worth reviewing. + -- The following is my synopsis of things which roughly coincide with the + -- simplified OpenGL ES 2.0. + -- ** Objects -- | Objects may be created and destroyed by client code. They include: -- @@ -159,15 +256,15 @@ -- - The __vertex shader__ takes vertex positions as specified in vertex -- attributes to clip space. This is how the client code specifies a camera, -- movement of objects, and perspective. - -- - The __perspective division__ or ""W-divide"" takes vertices from clip space - -- and maps them to normalized device coordinates (NDC) by dividing all the - -- components of the vertex by that vertex's W component. This allows a + -- - The __perspective division__ or ""W-divide"" takes vertices from clip + -- space and maps them to normalized device coordinates (NDC) by dividing all + -- the components of the vertex by that vertex's W component. This allows a -- perspective effect to be accomplished in the shader by modifying the W -- components. You can't configure this W-division; it just happens. Note - -- that if W = 1 for all vertices this step has no effect. This is useful for - -- orthographic projections. The resulting geometry will be clipped to a - -- 2x2x2 cube centered around the origin. You can think of an XY plane of - -- this cube as the viewport of the final 2D image. + -- that if W = 1 for all vertices then this step has no effect. This is + -- useful for orthographic projections. The resulting geometry will be + -- clipped to a 2x2x2 cube centered around the origin. You can think of an XY + -- plane of this cube as the viewport of the final 2D image. -- - The configurable __viewport transformation__ ('setViewport') will then -- position the viewport somewhere in the window. This step is necessary -- because your window is probably not a 2x2 square. The viewport diff --git a/Graphics/GL/Low/BufferObject.hs b/Graphics/GL/Low/BufferObject.hs --- a/Graphics/GL/Low/BufferObject.hs +++ b/Graphics/GL/Low/BufferObject.hs @@ -1,3 +1,4 @@ +{-# LANGUAGE ScopedTypeVariables #-} -- | VBO and ElementArrays. Both are buffer objects but are used for two -- different things. module Graphics.GL.Low.BufferObject ( @@ -14,6 +15,7 @@ ) where import Foreign.Ptr +import Foreign.ForeignPtr import Foreign.Marshal import Foreign.Storable import qualified Data.Vector.Storable as V @@ -57,17 +59,8 @@ -- | Create a buffer object from a blob of bytes. The usage argument hints -- at how often you will modify the data. -newVBO :: Vector Word8 -> UsageHint -> IO VBO -newVBO src usage = do - n <- alloca (\ptr -> glGenBuffers 1 ptr >> peek ptr) - let len = V.length src - glBindBuffer GL_ARRAY_BUFFER n - V.unsafeWith src $ \ptr -> glBufferData - GL_ARRAY_BUFFER - (fromIntegral len) - (castPtr ptr) - (toGL usage) - return (VBO n) +newVBO :: Storable a => Vector a -> UsageHint -> IO VBO +newVBO = newBufferObject VBO GL_ARRAY_BUFFER -- | Delete a VBO or ElementArray. deleteBufferObject :: BufferObject a => a -> IO () @@ -75,14 +68,8 @@ -- | Modify the data in the currently bound VBO starting from the specified -- index in bytes. -updateVBO :: Vector Word8 -> Int -> IO () -updateVBO src offset = do - let len = V.length src - V.unsafeWith src $ \ptr -> glBufferSubData - GL_ARRAY_BUFFER - (fromIntegral offset) - (fromIntegral len) - (castPtr ptr) +updateVBO :: Storable a => Vector a -> Int -> IO () +updateVBO = updateBufferObject GL_ARRAY_BUFFER -- | Bind a VBO to the array buffer binding target. The buffer object bound -- there will be replaced, if any. @@ -92,32 +79,42 @@ -- | Create a new ElementArray buffer object from the blob of packed indices. -- The usage argument hints at how often you plan to modify the data. -newElementArray :: Vector Word8 -> UsageHint -> IO ElementArray -newElementArray bytes usage = do - n <- alloca (\ptr -> glGenBuffers 1 ptr >> peek ptr) - glBindBuffer GL_ELEMENT_ARRAY_BUFFER n - let len = V.length bytes - V.unsafeWith bytes $ \ptr -> do - glBufferData - GL_ELEMENT_ARRAY_BUFFER - (fromIntegral len) - (castPtr ptr) - (toGL usage) - return (ElementArray n) +newElementArray :: Storable a => Vector a -> UsageHint -> IO ElementArray +newElementArray = newBufferObject ElementArray GL_ELEMENT_ARRAY_BUFFER -- | Modify contents in the currently bound ElementArray starting at the -- specified index in bytes. -updateElementArray :: Vector Word8 -> Int -> IO () -updateElementArray bytes offset = V.unsafeWith bytes $ \ptr -> do - glBufferSubData - GL_ELEMENT_ARRAY_BUFFER - (fromIntegral offset) - (fromIntegral (V.length bytes)) - (castPtr ptr) - +updateElementArray :: Storable a => Vector a -> Int -> IO () +updateElementArray = updateBufferObject GL_ELEMENT_ARRAY_BUFFER -- | Assign an ElementArray to the element array binding target. It will -- replace the ElementArray already bound there, if any. Note that the state -- of the element array binding target is a function of the current VAO. bindElementArray :: ElementArray -> IO () bindElementArray (ElementArray n) = glBindBuffer GL_ELEMENT_ARRAY_BUFFER n + + +newBufferObject :: forall a b . Storable a => (GLuint -> b) -> GLenum -> Vector a -> UsageHint -> IO b +newBufferObject ctor target src usage = do + n <- alloca (\ptr -> glGenBuffers 1 ptr >> peek ptr) + glBindBuffer target n + let (fptr, off, len) = V.unsafeToForeignPtr src + let size = sizeOf (undefined :: a) + withForeignPtr fptr $ \ptr -> glBufferData + target + (fromIntegral (len * size)) + (castPtr (ptr `plusPtr` off)) + (toGL usage) + return (ctor n) + +updateBufferObject :: forall a . Storable a => GLenum -> Vector a -> Int -> IO () +updateBufferObject target bytes offset = do + let (fptr, off, len) = V.unsafeToForeignPtr bytes + let size = sizeOf (undefined :: a) + withForeignPtr fptr $ \ptr -> glBufferSubData + target + (fromIntegral offset) + (fromIntegral (len * size)) + (castPtr (ptr `plusPtr` off)) + + diff --git a/Graphics/GL/Low/Render.hs b/Graphics/GL/Low/Render.hs --- a/Graphics/GL/Low/Render.hs +++ b/Graphics/GL/Low/Render.hs @@ -87,7 +87,7 @@ drawTriangleFan = drawArrays GL_TRIANGLE_FAN drawArrays :: GLenum -> Int -> IO () -drawArrays mode n = glDrawArrays mode (fromIntegral n) 0 +drawArrays mode n = glDrawArrays mode 0 (fromIntegral n) drawIndexedPoints :: Int -> IndexFormat -> IO () drawIndexedPoints = drawIndexed GL_POINTS diff --git a/Graphics/GL/Low/VertexAttrib.hs b/Graphics/GL/Low/VertexAttrib.hs --- a/Graphics/GL/Low/VertexAttrib.hs +++ b/Graphics/GL/Low/VertexAttrib.hs @@ -116,12 +116,17 @@ let total = totalLayout layout forM_ layout' $ \(name, size, offset, fmt) -> do attrib <- withCString name $ \ptr -> glGetAttribLocation (fromIntegral p) (castPtr ptr) + let stride = total - size * sizeOfVertexComponent fmt let norm = isNormalized fmt glVertexAttribPointer (fromIntegral attrib) (fromIntegral size) (toGL fmt) - (fromIntegral . fromEnum $ norm) - (fromIntegral offset) + (toGL norm) + (fromIntegral stride) (castPtr (nullPtr `plusPtr` offset)) glEnableVertexAttribArray (fromIntegral attrib) + +instance ToGL Bool where + toGL True = GL_TRUE + toGL False = GL_FALSE diff --git a/lowgl.cabal b/lowgl.cabal --- a/lowgl.cabal +++ b/lowgl.cabal @@ -10,7 +10,7 @@ -- PVP summary: +-+------- breaking API changes -- | | +----- non-breaking API additions -- | | | +--- code changes with no API change -version: 0.2.0.1 +version: 0.2.1.0 -- A short (one-line) description of the package. synopsis: Basic gl wrapper and reference @@ -89,4 +89,4 @@ source-repository this type: git location: https://github.com/evanrinehart/lowgl - tag: 0.2.0.1 + tag: 0.2.1.0