initial broken commit

README.md

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+# wasm-raytracer

app/Main.hs

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+module Main where
+
+import Control.Monad (mapM)
+import Control.Monad.Random
+import Data.Ix
+import Data.Maybe
+import Debug.Trace
+import Hittable
+import Linear.V2
+import Linear.V3
+import Linear.Vector
+import Maths
+import Ray
+import Text.Printf
+
+type Color = (Double, Double, Double)
+
+type Coord = (Int, Int)
+
+type ImageDimensions = (Int, Int)
+
+type ViewPortDimensions = (Double, Double)
+
+-- TODO
+-- add multiple samples per pixel
+-- fix coordinate system
+-- DONE fix random number generator
+
+backgroundColor = V3 0.0 0.0 0.0
+
+-- getRayColor :: (Shape s, RandomGen g) => [s] -> Int -> Ray Double -> Rand g (V3 Double)
+-- need to accumulate somewhere
+getRayColor ws d r = do
+  let h = getBestHit (mapMaybe (testHit r) ws)
+  v <- getRayColor' r h ws d
+  return $ v
+
+getRayColor' :: (Shape s, RandomGen g) => Ray Double -> Maybe Hit -> [s] -> Int -> Rand g (V3 Double)
+getRayColor' (Ray o d) Nothing _ _ = do return $ colorGradient (unitVector d)
+getRayColor' _ _ _ 0 = do return $ backgroundColor
+getRayColor' (Ray o d) (Just (Hit t p n)) ws depth =
+  do
+    r <- randV3
+    let target = p ^+^ n ^+^ r
+    nextVal <- (getRayColor ws (depth - 1) (Ray p (target ^-^ p)))
+    return $ colorWithNormal (calculateRayNormal (Ray o d) t) ^+^ (0.5 *^ nextVal)
+
+colorGradient :: V3 Double -> V3 Double
+colorGradient (V3 x y z) = do
+  let t = 0.5 * (y + 1.0)
+  (1.0 - t) *^ V3 1.0 1.0 1.0 + t *^ V3 0.5 0.7 1.0
+
+getBestHit :: [Hit] -> Maybe Hit
+getBestHit [] = Nothing
+getBestHit (h : hs) = Just (getBestHit' hs h)
+
+getBestHit' :: [Hit] -> Hit -> Hit
+getBestHit' (h : hs) bestHit =
+  if root h > root bestHit
+    then getBestHit' hs h
+    else getBestHit' hs bestHit
+getBestHit' [] hit = hit
+
+colorWithNormal :: V3 Double -> V3 Double
+colorWithNormal v = 0.5 *^ (v ^+^ V3 1.0 1.0 1.0)
+
+rayTrace :: (Shape s, RandomGen g) => (Int, Int) -> ImageDimensions -> ViewPortDimensions -> [s] -> Rand g (V3 Double)
+rayTrace (x, y) (w, h) (vw, vh) world = do
+  getRayColor world 50 (buildRay (xf * (vw / wf)) (yf * (vh / hf)))
+  where
+    xf = fromIntegral x
+    yf = fromIntegral y
+    wf = fromIntegral (w - 1)
+    hf = fromIntegral (h - 1)
+
+colorToString :: Color -> IO ()
+colorToString (x, y, z) = tupToString (xr, yr, zr)
+  where
+    xr = round (x * 255.0)
+    yr = round (y * 255.0)
+    zr = round (z * 255.0)
+
+tupToString :: (Show a) => (a, a, a) -> IO ()
+tupToString (x, y, z) = putStrLn (show x ++ " " ++ show y ++ " " ++ show z)
+
+v3ToColor :: V3 Double -> Color
+v3ToColor (V3 x y z) = (x, y, z)
+
+main :: IO ()
+main = do
+  let w = 400
+  let h = 400
+  -- weirdly, the bottom circle appears on top and bottom
+  let world = [Circle (V3 0.0 0.0 1.0) 0.25, Circle (V3 0.0 (-10.05) 1.0) 10]
+  let coords = range ((-1 * (w `div` 2), -1 * (h `div` 2)), ((w `div` 2) - 1, (h `div` 2) - 1)) -- "canvas"
+  --let aspect = 16.0 / 9.0
+  g <- getStdGen
+  let colors = map (\x -> foldl (^+^) (V3 0.0 0.0 0.0) $ replicate 50 $ evalRand (rayTrace x (w - 1, h - 1) (1.0, 1.0) world) g) coords
+  let convertedColors = map v3ToColor colors
+  --mapM_ print colors
+  putStrLn "P3"
+  putStrLn (show w ++ " " ++ show h)
+  putStrLn "255"
+  mapM_ colorToString convertedColors

package.yaml

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+name:                wasm-raytracer
+version:             0.1.0.0
+github:              "githubuser/wasm-raytracer"
+license:             BSD3
+author:              "Author name here"
+maintainer:          "example@example.com"
+copyright:           "2022 Author name here"
+
+extra-source-files:
+- README.md
+- ChangeLog.md
+
+# Metadata used when publishing your package
+# synopsis:            Short description of your package
+# category:            Web
+
+# To avoid duplicated efforts in documentation and dealing with the
+# complications of embedding Haddock markup inside cabal files, it is
+# common to point users to the README.md file.
+description:         Please see the README on GitHub at <https://github.com/githubuser/wasm-raytracer#readme>
+
+dependencies:
+- base >= 4.7 && < 5
+- linear
+- random
+- mtl
+- MonadRandom
+library:
+  source-dirs: src
+
+executables:
+  wasm-raytracer-exe:
+    main:                Main.hs
+    source-dirs:         app
+    ghc-options:
+    - -threaded
+    - -rtsopts
+    - -with-rtsopts=-N
+    dependencies:
+    - wasm-raytracer
+
+tests:
+  wasm-raytracer-test:
+    main:                Spec.hs
+    source-dirs:         test
+    ghc-options:
+    - -threaded
+    - -rtsopts
+    - -with-rtsopts=-N
+    dependencies:
+    - wasm-raytracer

src/Hittable.hs

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+module Hittable (Shape (..), Circle (..), Hit (..)) where
+
+import Linear.V3
+import Linear.Vector
+import Maths
+import Ray
+
+class Shape s where
+  testHit :: Ray Double -> s -> Maybe Hit
+
+data Circle = Circle (V3 Double) Double
+
+data Hit = Hit {root :: Double, p :: V3 Double, n :: V3 Double}
+
+instance Shape Circle where
+  testHit (Ray o d) (Circle center r) =
+    if discriminant < 0.0
+      then Nothing
+      else Just (Hit root p (p - center ^/ r))
+    where
+      co = o - center
+      a = lengthSquared d -- a vector dotted with itself is = lengthSquared
+      b = d `dotP` co
+      c = lengthSquared co - r ^ 2
+      discriminant = b ^ 2 - a * c
+      root = (b * (-1.0) - sqrt discriminant) / a
+      p = rayAt (Ray o d) root
+
+-- would make sense to build a Functor for shapes

src/Maths.hs

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+module Maths
+  ( dotP,
+    lengthSquared,
+    unitVector,
+    randV3,
+    rand,
+  )
+where
+
+import Control.Monad.Random
+import Control.Monad.State (State, evalState, get, put)
+import Debug.Trace
+import Linear.V3
+import Linear.Vector
+import System.Random
+
+rand :: (RandomGen g) => Rand g Double
+rand = getRandomR (-1.0, 1.0 :: Double)
+
+randV3 :: (RandomGen g) => Rand g (V3 Double)
+randV3 = do
+  x <- rand
+  y <- rand
+  z <- rand
+  return $ V3 x y z
+
+--  _ -> randV3
+
+--inf = read "Infinity"
+
+degToRadians :: (Floating a) => a -> a
+degToRadians d = (d * pi) / 180.0
+
+dotP :: (Num a) => V3 a -> V3 a -> a
+dotP (V3 a b c) (V3 d e f) = a * d + b * e + c * f
+
+lengthSquared :: (Num a) => V3 a -> a
+lengthSquared (V3 x y z) = x ^ 2 + y ^ 2 + z ^ 2
+
+vectorLength :: (Floating f) => V3 f -> f
+vectorLength v = sqrt (lengthSquared v)
+
+unitVector :: (Floating f) => V3 f -> V3 f
+unitVector v = v ^/ vectorLength v

src/Ray.hs

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+module Ray
+  ( Ray (..),
+    rayAt,
+    calculateRayNormal,
+    buildRay,
+  )
+where
+
+import Linear.V3
+import Linear.Vector
+import Maths
+
+data Ray f = Ray (V3 f) (V3 f)
+
+-- P(t) = A + tB; A is origin, B is direction
+rayAt :: (Floating f) => Ray f -> f -> V3 f
+rayAt (Ray origin dir) t = origin + (t *^ dir)
+
+-- get the normal of the point at t
+calculateRayNormal :: (Floating f) => Ray f -> f -> V3 f
+calculateRayNormal r t = unitVector (rayAt r t ^-^ V3 0.0 0.0 1.0)
+
+buildRay :: (Floating f) => f -> f -> Ray f
+buildRay u v = Ray (V3 0.0 0.0 0.0) (V3 v u 1.0)

stack.yaml

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+# This file was automatically generated by 'stack init'
+#
+# Some commonly used options have been documented as comments in this file.
+# For advanced use and comprehensive documentation of the format, please see:
+# https://docs.haskellstack.org/en/stable/yaml_configuration/
+
+# Resolver to choose a 'specific' stackage snapshot or a compiler version.
+# A snapshot resolver dictates the compiler version and the set of packages
+# to be used for project dependencies. For example:
+#
+# resolver: lts-3.5
+# resolver: nightly-2015-09-21
+# resolver: ghc-7.10.2
+#
+# The location of a snapshot can be provided as a file or url. Stack assumes
+# a snapshot provided as a file might change, whereas a url resource does not.
+#
+# resolver: ./custom-snapshot.yaml
+# resolver: https://example.com/snapshots/2018-01-01.yaml
+resolver:
+  url: https://raw.githubusercontent.com/commercialhaskell/stackage-snapshots/master/lts/19/15.yaml
+
+# User packages to be built.
+# Various formats can be used as shown in the example below.
+#
+# packages:
+# - some-directory
+# - https://example.com/foo/bar/baz-0.0.2.tar.gz
+#   subdirs:
+#   - auto-update
+#   - wai
+packages:
+- .
+# Dependency packages to be pulled from upstream that are not in the resolver.
+# These entries can reference officially published versions as well as
+# forks / in-progress versions pinned to a git hash. For example:
+#
+# extra-deps:
+# - acme-missiles-0.3
+# - git: https://github.com/commercialhaskell/stack.git
+#   commit: e7b331f14bcffb8367cd58fbfc8b40ec7642100a
+#
+# extra-deps: []
+
+# Override default flag values for local packages and extra-deps
+# flags: {}
+
+# Extra package databases containing global packages
+# extra-package-dbs: []
+
+# Control whether we use the GHC we find on the path
+# system-ghc: true
+#
+# Require a specific version of stack, using version ranges
+# require-stack-version: -any # Default
+# require-stack-version: ">=2.7"
+#
+# Override the architecture used by stack, especially useful on Windows
+# arch: i386
+# arch: x86_64
+#
+# Extra directories used by stack for building
+# extra-include-dirs: [/path/to/dir]
+# extra-lib-dirs: [/path/to/dir]
+#
+# Allow a newer minor version of GHC than the snapshot specifies
+# compiler-check: newer-minor

wasm-raytracer.cabal

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+cabal-version: 1.12
+
+-- This file has been generated from package.yaml by hpack version 0.34.7.
+--
+-- see: https://github.com/sol/hpack
+
+name:           wasm-raytracer
+version:        0.1.0.0
+description:    Please see the README on GitHub at <https://github.com/githubuser/wasm-raytracer#readme>
+homepage:       https://github.com/githubuser/wasm-raytracer#readme
+bug-reports:    https://github.com/githubuser/wasm-raytracer/issues
+author:         Author name here
+maintainer:     example@example.com
+copyright:      2022 Author name here
+license:        BSD3
+license-file:   LICENSE
+build-type:     Simple
+extra-source-files:
+    README.md
+    ChangeLog.md
+
+source-repository head
+  type: git
+  location: https://github.com/githubuser/wasm-raytracer
+
+library
+  exposed-modules:
+      Hittable
+      Maths
+      Ray
+  other-modules:
+      Paths_wasm_raytracer
+  hs-source-dirs:
+      src
+  build-depends:
+      MonadRandom
+    , base >=4.7 && <5
+    , linear
+    , mtl
+    , random
+  default-language: Haskell2010
+
+executable wasm-raytracer-exe
+  main-is: Main.hs
+  other-modules:
+      Paths_wasm_raytracer
+  hs-source-dirs:
+      app
+  ghc-options: -threaded -rtsopts -with-rtsopts=-N
+  build-depends:
+      MonadRandom
+    , base >=4.7 && <5
+    , linear
+    , mtl
+    , random
+    , wasm-raytracer
+  default-language: Haskell2010
+
+test-suite wasm-raytracer-test
+  type: exitcode-stdio-1.0
+  main-is: Spec.hs
+  other-modules:
+      Paths_wasm_raytracer
+  hs-source-dirs:
+      test
+  ghc-options: -threaded -rtsopts -with-rtsopts=-N
+  build-depends:
+      MonadRandom
+    , base >=4.7 && <5
+    , linear
+    , mtl
+    , random
+    , wasm-raytracer
+  default-language: Haskell2010