{-# LANGUAGE OverloadedLists #-}

module Render.Skybox.Pipeline
  ( Pipeline
  , allocate
  ) where

import RIO

import Control.Monad.Trans.Resource (ResourceT)
import Data.Tagged (Tagged(..))
import Vulkan.Core10 qualified as Vk
import Vulkan.Zero (Zero(..))

import Engine.Vulkan.Pipeline (Config(..))
import Engine.Vulkan.Pipeline qualified as Pipeline
import Engine.Vulkan.Types (HasVulkan, HasRenderPass(..), DsBindings)
import Render.Code (compileVert, compileFrag, glsl)
import Render.DescSets.Set0 (Scene)
import Render.DescSets.Set0.Code (set0binding0, set0binding1, set0binding3)

type Pipeline = Pipeline.Pipeline '[Scene] () ()

allocate
  :: ( HasVulkan env
     , HasRenderPass renderpass
     )
  => Vk.SampleCountFlagBits
  -> Tagged Scene DsBindings
  -> renderpass
  -> ResourceT (RIO env) Pipeline
allocate :: SampleCountFlagBits
-> Tagged Scene DsBindings
-> renderpass
-> ResourceT (RIO env) Pipeline
allocate SampleCountFlagBits
multisample (Tagged DsBindings
set0) = do
  ((ReleaseKey, Pipeline) -> Pipeline)
-> ResourceT (RIO env) (ReleaseKey, Pipeline)
-> ResourceT (RIO env) Pipeline
forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
fmap (ReleaseKey, Pipeline) -> Pipeline
forall a b. (a, b) -> b
snd (ResourceT (RIO env) (ReleaseKey, Pipeline)
 -> ResourceT (RIO env) Pipeline)
-> (renderpass -> ResourceT (RIO env) (ReleaseKey, Pipeline))
-> renderpass
-> ResourceT (RIO env) Pipeline
forall b c a. (b -> c) -> (a -> b) -> a -> c
. Maybe Extent2D
-> SampleCountFlagBits
-> Config '[Scene] () ()
-> renderpass
-> ResourceT (RIO env) (ReleaseKey, Pipeline)
forall env (m :: * -> *) renderpass (dsl :: [*]) vertices
       instances.
(MonadVulkan env m, MonadResource m, HasRenderPass renderpass,
 HasCallStack) =>
Maybe Extent2D
-> SampleCountFlagBits
-> Config dsl vertices instances
-> renderpass
-> m (ReleaseKey, Pipeline dsl vertices instances)
Pipeline.allocate
    Maybe Extent2D
forall a. Maybe a
Nothing
    SampleCountFlagBits
multisample
    Config Any Any Any
forall a. Zero a => a
zero
      { $sel:cVertexCode:Config :: Maybe ByteString
cVertexCode         = ByteString -> Maybe ByteString
forall a. a -> Maybe a
Just ByteString
vertCode
      , $sel:cFragmentCode:Config :: Maybe ByteString
cFragmentCode       = ByteString -> Maybe ByteString
forall a. a -> Maybe a
Just ByteString
fragCode
      , $sel:cDescLayouts:Config :: Tagged '[Scene] [DsBindings]
cDescLayouts        = [DsBindings] -> Tagged '[Scene] [DsBindings]
forall k (s :: k) b. b -> Tagged s b
Tagged @'[Scene] [DsBindings
Item [DsBindings]
set0]
      , $sel:cCull:Config :: CullModeFlagBits
cCull               = CullModeFlagBits
Vk.CULL_MODE_NONE
      }

vertCode :: ByteString
vertCode :: ByteString
vertCode =
  $(compileVert [glsl|
    #version 450
    #extension GL_ARB_separate_shader_objects : enable

    ${set0binding0}

    layout(location = 0) out vec3 fragUVW;

    float farZ = 0.9999; // 1 - 1e-7;

    void main() {
      vec4 pos = vec4(0.0);
      switch(gl_VertexIndex) {
          case 0: pos = vec4(-1.0,  3.0, farZ, 1.0); break;
          case 1: pos = vec4(-1.0, -1.0, farZ, 1.0); break; // XXX: swapped with 2. culling?
          case 2: pos = vec4( 3.0, -1.0, farZ, 1.0); break;
      }

      vec3 unProjected = (scene.invProjection * pos).xyz;
      unProjected *= -1;
      fragUVW = mat3(scene.invView) * unProjected;

      gl_Position = pos;
    }
  |])

fragCode :: ByteString
fragCode :: ByteString
fragCode =
  $(compileFrag [glsl|
    #version 450
    #extension GL_ARB_separate_shader_objects : enable
    #extension GL_EXT_nonuniform_qualifier : enable

    ${set0binding0}

    ${set0binding1}
    ${set0binding3}

    layout(location = 0) in vec3 fragUVW;

    layout(location = 0) out vec4 outColor;

    void main() {
      if (scene.envCubeId > -1) {
        outColor = texture(
          samplerCube(
            cubes[nonuniformEXT(scene.envCubeId)],
            samplers[2] // XXX: linear/mip0/repeat
          ),
          fragUVW
        );
      }
    }
  |])