module Types.Sprite where

import SDL (get, ($=))

import qualified Graphics.Rendering.OpenGL as GL
import qualified Graphics.GLUtil as GLUtil

import Codec.Picture

import Linear

-- internal imports

import Classes.Renderable

data SpriteRenderObjects = SpriteRenderObjects
  { roVAO :: GL.VertexArrayObject
  , roVBO :: GL.BufferObject
  }

data SpriteShaderObjects = SpriteShaderobjects
  { soVertexShader   :: GL.Shader
  , soFragmentShader :: GL.Shader
  , soProgram        :: GL.Program
  }

data Sprite = Sprite
  { spritePosition :: V2 Int
  , SpriteImage    :: Image PixelRGBA8
  }

instance Renderable Sprite where
  type VertexObjects Sprite = SpriteRenderObjects

  type ShaderObjects Sprite = SpriteShaderObjects

  init (SpriteRenderObjects vao vbo) = do
    GL.currenProgram $= Just prog
    GL.bindVertexArrayObject $= Just vao

  draw
    (SpriteRenderObjects vao vbo)
    (SpriteShaderObjects vs fs prog)
    (Sprite pos@(V2 px py) img) = do
      let model = mkTransformation
            (Quaternion (V3 0 0 0) 1 :: Quaternion Float)
            (fmap fromIntegral $ V3 px py 0 :: V3 Float)
      GLU.setUniform program "model" model
      uLoc <- get (GL.uniformLocation prog "model")
      GL.uniform uLoc $= model
      GL.drawArrays GL.Triangles 0 6

  clean =
    GL.currenProgram $= Nothing
    GL.bindVertexArrayObject $= Nothing