add example

flake.nix

@@ -10,52 +10,6 @@
     self,
     ...
   }: let
-    version = "0.1.0";
-    package = {
-      # nix stuff
-      mkDerivation,
-      lib,
-      # haskell deps
-      base,
-      c-expr-runtime,
-      hs-bindgen-runtime,
-      # pkgconfig deps
-      libGL,
-      libX11,
-      libXcursor,
-      libXi,
-      xrandr,
-      # shell deps
-      clang,
-      hs-bindgen-cli,
-      tree,
-    }:
-      mkDerivation {
-        pname = "hs-rgfw";
-        inherit version;
-        src = ./.;
-        libraryHaskellDepends = [
-          base
-          c-expr-runtime
-          hs-bindgen-runtime
-        ];
-        libraryPkgconfigDepends = [
-          libGL
-          libX11
-          libXcursor
-          libXi
-          xrandr
-        ];
-        preConfigure = ''
-          set -x
-          export PATH=${clang}/bin:${hs-bindgen-cli}/bin:${tree}/bin:$PATH
-          ./generate.sh
-          set +x
-        '';
-        homepage = "https://git.mtgmonkey.net/Andromeda/hs-rgfw";
-        license = lib.licenses.gpl3Only;
-        platforms = ["x86_64-linux"];
-      };
     system = "x86_64-linux";
     pkgs = import nixpkgs {
       inherit system;
@@ -69,6 +23,8 @@
       default = pkgs.mkShell {
         stdenv = pkgs.clangStdenv;
         packages = [
+          pkgs.haskellPackages.ghcide
+          pkgs.haskellPackages.ormolu
           pkgs.clang
           pkgs.cabal-install
           pkgs.hs-bindgen-cli
@@ -80,7 +36,18 @@
       };
     };
     packages.${system} = {
-      default = pkgs.haskellPackages.callPackage package {};
+      default =
+        (pkgs.haskell.packages.ghc912.callCabal2nix "hs-rgfw" ./. {
+          xi = pkgs.libxi;
+          gl = pkgs.libGL;
+          xcursor = pkgs.libxcursor;
+          xrandr = pkgs.xrandr;
+        }).overrideAttrs {
+          preConfigure = ''
+            export PATH=${pkgs.clang}/bin:${pkgs.hs-bindgen-cli}/bin:${pkgs.tree}/bin:$PATH
+            ./generate.sh
+          '';
+        };
     };
   };
 }

hs-rgfw.cabal

@@ -40,9 +40,11 @@ executable hs-rgfw
   main-is: Main.hs
   build-depends:
     , base
-    , hs-rgfw
+    , bytestring
     , c-expr-runtime
     , hs-bindgen-runtime
+    , hs-rgfw
+    , OpenGL
   pkgconfig-depends:
     , gl
     , x11

src/LoadShaders.hs

@@ -0,0 +1,91 @@
+--------------------------------------------------------------------------------
+
+--------------------------------------------------------------------------------
+
+-- |
+-- Module      :  LoadShaders
+-- Copyright   :  (c) Sven Panne 2013
+-- License     :  BSD3
+--
+-- Maintainer  :  Sven Panne <svenpanne@gmail.com>
+-- Stability   :  stable
+-- Portability :  portable
+--
+-- Utilities for shader handling, adapted from LoadShaders.cpp which is (c) The
+-- Red Book Authors.
+module LoadShaders
+  ( ShaderSource (..),
+    ShaderInfo (..),
+    loadShaders,
+  )
+where
+
+import Control.Exception
+import Control.Monad
+import qualified Data.ByteString as B
+import Graphics.Rendering.OpenGL
+
+--------------------------------------------------------------------------------
+
+-- | The source of the shader source code.
+data ShaderSource
+  = -- | The shader source code is directly given as a 'B.ByteString'.
+    ByteStringSource B.ByteString
+  | -- | The shader source code is directly given as a 'String'.
+    StringSource String
+  | -- | The shader source code is located in the file at the given 'FilePath'.
+    FileSource FilePath
+  deriving (Eq, Ord, Show)
+
+getSource :: ShaderSource -> IO B.ByteString
+getSource (ByteStringSource bs) = return bs
+getSource (StringSource str) = return $ packUtf8 str
+getSource (FileSource path) = B.readFile path
+
+--------------------------------------------------------------------------------
+
+-- | A description of a shader: The type of the shader plus its source code.
+data ShaderInfo
+  = ShaderInfo ShaderType ShaderSource
+  deriving (Eq, Ord, Show)
+
+--------------------------------------------------------------------------------
+
+-- | Create a new program object from the given shaders, throwing an
+-- 'IOException' if something goes wrong.
+loadShaders :: [ShaderInfo] -> IO Program
+loadShaders infos =
+  createProgram `bracketOnError` deleteObjectName $ \program -> do
+    loadCompileAttach program infos
+    linkAndCheck program
+    return program
+
+linkAndCheck :: Program -> IO ()
+linkAndCheck = checked linkProgram linkStatus programInfoLog "link"
+
+loadCompileAttach :: Program -> [ShaderInfo] -> IO ()
+loadCompileAttach _ [] = return ()
+loadCompileAttach program (ShaderInfo shType source : infos) =
+  createShader shType `bracketOnError` deleteObjectName $ \shader -> do
+    src <- getSource source
+    shaderSourceBS shader $= src
+    compileAndCheck shader
+    attachShader program shader
+    loadCompileAttach program infos
+
+compileAndCheck :: Shader -> IO ()
+compileAndCheck = checked compileShader compileStatus shaderInfoLog "compile"
+
+checked ::
+  (t -> IO ()) ->
+  (t -> GettableStateVar Bool) ->
+  (t -> GettableStateVar String) ->
+  String ->
+  t ->
+  IO ()
+checked action getStatus getInfoLog message object = do
+  action object
+  ok <- get (getStatus object)
+  unless ok $ do
+    infoLog <- get (getInfoLog object)
+    fail (message ++ " log: " ++ infoLog)

src/Main.hs

@@ -1,37 +1,89 @@
+{-# LANGUAGE MultilineStrings #-}
+
 module Main where
 
-import RGFW.Generated
-import Foreign.C.Types (CChar)
-import Foreign.C.String (newCString)
-import Foreign.C.ConstPtr
 import Data.Bits ((.|.))
+import Foreign.C.ConstPtr
+import Foreign.C.String (newCString)
+import Foreign.C.Types (CChar)
+import Foreign.Ptr (Ptr)
+import Graphics.Rendering.OpenGL (($=))
+import qualified Graphics.Rendering.OpenGL as GL
+import LoadShaders
+import RGFW.Generated
 
 main :: IO ()
 main = do
-
+  putStrInfo "creating window"
-  -- disable wayland, can't be bothered
+  -- string not freed; window remains open
-  _ <- rGFW_useWayland_safe $ RGFW_bool 0
-
-  -- create window. This string does not need to be freed, the window stays open
   windowTitle_cstr <- newCString "window"
-  let
+  let windowTitle_ptr = ConstPtr windowTitle_cstr
-    windowTitle_ptr = ConstPtr windowTitle_cstr
+      windowFlags = RGFW_windowFlags $ fromIntegral $ RGFW_windowCenter .|. RGFW_windowNoResize .|. RGFW_windowOpenGL
-    windowFlags = RGFW_windowFlags $ fromIntegral $ RGFW_windowCenter .|. RGFW_windowNoResize .|. RGFW_windowOpenGL
 
-  window_ptr <- rGFW_createWindow_safe
+  window <-
-    windowTitle_ptr -- name
+    rGFW_createWindow_safe
-    100 -- x
+      windowTitle_ptr -- name
-    100 -- y
+      0 -- x
-    100 -- w
+      0 -- y
-    100 -- h
+      300 -- w
-    windowFlags -- flags
+      300 -- h
-  putDebug $ "windowFlags: " ++ (show $ unwrapU32 $ unwrapRGFW_windowFlags windowFlags)
+      windowFlags -- flags
-  putDebug $ "window_ptr: " ++ (show $ window_ptr)
+  putStrDebug $ "windowFlags: " ++ (show $ unwrapU32 $ unwrapRGFW_windowFlags windowFlags)
-  putDebug "created window"
+  putStrDebug $ "window: " ++ (show $ window)
-  loop 0
+  putStrInfo "initialising shaders"
+  _ <- initResources
+  putStrInfo "entering loop"
+  loop window 0
 
-loop :: Int -> IO ()
+loop :: Ptr RGFW_window -> Int -> IO ()
-loop i = loop $ i + 1
+loop window i = do
+  view
+  rGFW_window_swapBuffers_OpenGL_safe window
+  loop window $ i + 1
 
-putDebug :: String -> IO ()
+putStrDebug :: String -> IO ()
-putDebug a = putStrLn $ "[debug] " ++ a
+putStrDebug a = putStrLn $ "[debug]:" ++ a
+
+putStrInfo :: String -> IO ()
+putStrInfo a = putStrLn $ "[info]:" ++ a
+
+initResources :: IO GL.Program
+initResources = do
+  program <-
+    loadShaders
+      [ ShaderInfo GL.VertexShader $ StringSource vertShader,
+        ShaderInfo GL.FragmentShader $ StringSource fragShader
+      ]
+  GL.currentProgram $= Just program
+  return program
+  where
+    vertShader =
+      """
+      #version 330 core
+      layout (location = 0) in vec3 aPos;
+
+      out vec4 vertexColor;
+
+      void main()
+      {
+        gl_Position = vec4(aPos, 1.0);
+        vertexColor = vec4(0.5, 0.0, 0.0, 1.0);
+      }
+      """
+    fragShader =
+      """
+      #version 330 core
+      out vec4 FragColor;
+
+      in vec4 vertexColor;
+
+      void main()
+      {
+        FragColor = vertexColor;
+      }
+      """
+
+view :: IO ()
+view = do
+  GL.clearColor $= GL.Color4 1 0 1 1
+  GL.clear [GL.ColorBuffer, GL.DepthBuffer]