{-# LANGUAGE GeneralizedNewtypeDeriving #-}
{-# LANGUAGE StrictData #-}
{-# LANGUAGE TemplateHaskell #-}

-- | Datatypes used to setup and pass data to shaders.
module Shader.Data (
    VAO (..),
    VBO (..),
    EBO (..),
    TO (..),
    FBO (..),
    Shader (..),
    PrimitiveMode (..),
    -- | Lens functions
    vaoName,
    shaderUINT,
    shaderPrimitive,
    shaderVAO,
    shaderTextures,
    textureObject,
    vboName,
    vboPtr,
    vboVertexSize,
    unFBO,
    unTO,
    unPrimitiveMode,
    eboName,
    eboPtr,
    -- | Synonyms
    vert,
    geom,
    frag,
    pmPoints,
    pmLines,
    pmLinesAdjacency,
    pmLineLoop,
    pmLineStrip,
    pmTriangles,
    pmTriangleStrip,
    pmTriangleFan,
    pmQuads,
    pmPatches,
) where

import Control.Lens
import Foreign
import Graphics.GL.Core45

-- | Datatype containing the necessary information for a single shader.
data Shader = Shader
    { _shaderUINT :: GLuint -- should be shaderID
    , _shaderPrimitive :: PrimitiveMode
    , _shaderVAO :: VAO
    , _shaderTextures :: [TO]
    }

newtype FBO = FBO {_unFBO :: GLuint}

newtype TO = TO {_unTO :: GLuint}

{- | Vertex array object: contains the reference to the object,
and its buffer targets.
-}
newtype VAO = VAO
    { _vaoName :: GLuint
    }

{- | Vertex buffer object: contains the reference to the object,
a pointer to a location with space that can be written to the buffer,
and a list of attribute pointer sizes.
Vertex attributes are interleaved within the vbo.
-}
data VBO = VBO
    { _vboName :: GLuint
    , _vboPtr :: Ptr Float
    , _vboVertexSize :: Int
    -- add int for AMOUNT of data poked!
    }

data EBO = EBO
    { _eboName :: GLuint
    , _eboPtr :: Ptr GLushort
    }

-- | Datatype containing the reference to a texture object.
newtype ShaderTexture = ShaderTexture
    { _textureObject :: GLuint -- DSA style texture, 450
    --    , _textureTarget :: GLenum
    }

newtype PrimitiveMode = PrimitiveMode {_unPrimitiveMode :: GLenum}

-- | Short synonyms for shader types
vert, geom, frag :: GLenum
vert = GL_VERTEX_SHADER
geom = GL_GEOMETRY_SHADER
frag = GL_FRAGMENT_SHADER

pmPoints, pmLines, pmLinesAdjacency, pmLineLoop, pmLineStrip, pmTriangles, pmTriangleStrip, pmTriangleFan, pmQuads, pmPatches :: PrimitiveMode
pmPoints = PrimitiveMode GL_POINTS
pmLines = PrimitiveMode GL_LINES
pmLinesAdjacency = PrimitiveMode GL_LINES_ADJACENCY
pmLineLoop = PrimitiveMode GL_LINE_LOOP
pmLineStrip = PrimitiveMode GL_LINE_STRIP
pmTriangles = PrimitiveMode GL_TRIANGLES
pmTriangleStrip = PrimitiveMode GL_TRIANGLE_STRIP
pmTriangleFan = PrimitiveMode GL_TRIANGLE_FAN
pmQuads = PrimitiveMode GL_QUADS
pmPatches = PrimitiveMode GL_PATCHES

makeLenses ''VAO
makeLenses ''VBO
makeLenses ''EBO
makeLenses ''ShaderTexture
makeLenses ''Shader
makeLenses ''FBO
makeLenses ''TO
makeLenses ''PrimitiveMode