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{- Vivant: Haskell OpenGL game.
Copyright (C) 2020 Yann Herklotz
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
-}
module Main where
import Control.Monad
import Foreign.C.Types
import Foreign.Ptr
import Foreign.Storable (sizeOf)
import SDL.Vect
import System.Exit (exitFailure)
import System.IO
import SDL (($=))
import SDL.Time (ticks)
import SDL.Raw.Video as SDL (glSetAttribute)
import SDL.Raw.Enum as SDL
import Data.Word (Word32)
import Linear
import qualified Graphics.Rendering.OpenGL as GL
import qualified Data.ByteString as BS
import qualified Data.Vector.Storable as V
import qualified SDL
import Paths_vivant (getDataDir)
import Vivant.Shader (createProgram)
screenWidth, screenHeight :: CInt
(screenWidth, screenHeight) = (640, 480)
data Camera = Camera
{ cameraPos :: V3 Float
, cameraUp :: V3 Float
, cameraFront :: V3 Float
, cameraSpeed :: Float
, cameraPitch :: Float
, cameraYaw :: Float
} deriving (Show)
initialCamera :: Camera
initialCamera = Camera
{ cameraPos = V3 0 0 3
, cameraUp = V3 0 1 0
, cameraFront = V3 0 0 (-1)
, cameraSpeed = 0.05
, cameraPitch = 0
, cameraYaw = (-90)
}
data Game = Game
{ gameProgram :: Maybe (GL.Program)
, gameVao :: Maybe (GL.VertexArrayObject)
, gameModelP :: Ptr (M44 Float)
, gameViewP :: Ptr (M44 Float)
, gameProjectionP :: Ptr (M44 Float)
, gameCamera :: Camera
} deriving (Show)
initialGameState :: Game
initialGameState = Game
{ gameProgram = Nothing
, gameVao = Nothing
, gameModelP = nullPtr
, gameViewP = nullPtr
, gameProjectionP = nullPtr
, gameCamera = initialCamera
}
main :: IO ()
main = do
SDL.initialize [SDL.InitVideo]
SDL.HintRenderScaleQuality $= SDL.ScaleLinear
do renderQuality <- SDL.get SDL.HintRenderScaleQuality
when (renderQuality /= SDL.ScaleLinear) $
putStrLn "Warning: Linear texture filtering not enabled!"
window <-
SDL.createWindow
"SDL / OpenGL Example"
SDL.defaultWindow {SDL.windowInitialSize = V2 screenWidth screenHeight,
SDL.windowGraphicsContext = SDL.OpenGLContext SDL.defaultOpenGL}
SDL.glSetAttribute SDL_GL_CONTEXT_PROFILE_MASK SDL_GL_CONTEXT_PROFILE_CORE
SDL.glSetAttribute SDL_GL_CONTEXT_MAJOR_VERSION 3
SDL.glSetAttribute SDL_GL_CONTEXT_MINOR_VERSION 2
SDL.glSetAttribute SDL_GL_DOUBLEBUFFER 1
SDL.glSetAttribute SDL_GL_DEPTH_SIZE 24
SDL.showWindow window
_ <- SDL.glCreateContext window
GL.viewport $= (GL.Position 0 0, GL.Size (fromIntegral screenWidth) (fromIntegral screenHeight))
game <- initResources
let loop = do
events <- SDL.pollEvents
let quit = elem SDL.QuitEvent $ map SDL.eventPayload events
draw game
SDL.glSwapWindow window
unless quit loop
loop
SDL.destroyWindow window
SDL.quit
setVertexAttribute :: GL.Program -> String -> Int -> Int -> Int -> IO ()
setVertexAttribute program name vertices stride offset = do
let floatSize = sizeOf (1.0 :: Float)
attrib <- GL.get $ GL.attribLocation program name
GL.vertexAttribPointer attrib $= (GL.ToFloat, GL.VertexArrayDescriptor 2 GL.Float
(fromIntegral $ stride * floatSize)
(plusPtr nullPtr (offset * floatSize)))
GL.vertexAttribArray attrib $= GL.Enabled
initResources :: IO Game
initResources = do
vao <- GL.genObjectName
GL.bindVertexArrayObject $= Just vao
vbo <- GL.genObjectName
GL.bindBuffer GL.ArrayBuffer $= Just vbo
V.unsafeWith vertices $ \ptr ->
GL.bufferData GL.ArrayBuffer $= (vectorSize vertices, castPtr ptr, GL.StaticDraw)
prog <- createProgram
setVertexAttribute prog "position" 2 0 0
return $ initialGameState { gameProgram = Just prog, gameVao = Just vao }
draw :: Game -> IO ()
draw game@(Game {gameProgram = Just p, gameVao = Just v}) = do
GL.clearColor $= GL.Color4 1 1 1 1
GL.clear [GL.ColorBuffer, GL.DepthBuffer]
GL.currentProgram $= gameProgram game
GL.bindVertexArrayObject $= gameVao game
ourColorLoc <- GL.uniformLocation p "ourColour"
tick <- ticks
GL.uniform ourColorLoc $= (GL.Vector4 (1::Float) (sin (fromIntegral tick / 500) / 2 + 0.5) 1 1)
GL.drawArrays GL.Triangles 0 6
GL.bindVertexArrayObject $= Nothing
return ()
vectorSize array = fromIntegral $ V.length array * sizeOf (1.0 :: Float)
vertices :: V.Vector Float
vertices = V.fromList [ 0.5, -0.5
, -0.5, -0.5
, 0.5, 0.5
, -0.5, 0.5
, -0.5, -0.5
, 0.5, 0.5
]
texCoords :: V.Vector Float
texCoords = V.fromList [ 0, 0
, 1, 0
, 0.5, 1
]
|
