-- ==================================
-- Module name: MyPrimitives
-- Project: Foo
-- Copyright (C) 2007  Bartosz Wójcik
-- Created on: 01.10.2007
-- Last update: 28.11.2007
-- Version: %

{-  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.

    You should have received a copy of the GNU General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.
-}
-- ==================================
module MyPrimitives where

import Graphics.UI.GLUT
import Graphics.Rendering.OpenGL

-- Displays given primitive with given list of 2D vertices.
-- displayPoints :: (Vertex (Vertex2 b)) => [(b, b)] -> PrimitiveMode -> IO ()
displayPoints points primitiveShape = do
  renderPrimitive primitiveShape $ mapM_ (\(x,y)->vertex$Vertex2 x y) points
--  flush

-- =========================================================================
-- Some functions creating and rendering circles in different configurations
-- =========================================================================

-- Returns list of vertices that construct circle.
-- Input - radius of circle and number of points constructing circle.
-- More points - circle is more precise, but function takes more time to construct it.
circlePoints :: (Floating a, Enum a) => a -> a -> [(a, a)]
circlePoints radius number
 = [let alpha = 2*pi*i/number
    in  (radius*(sin (alpha)) ,radius * (cos (alpha)))
   |i <- [1,2..number]]

-- Returns list of vertices that construct circle of given radius.
-- 64 points constructing circle were taken from experiment result.
circle :: (Floating a, Enum a) => a -> [(a, a)]
circle radius = circlePoints radius 64

-- Returns list of vertices that construct circle of given radius.
-- 16 points constructing circle were taken from experiment result for small circles.
circleSmall :: (Floating a, Enum a) => a -> [(a, a)]
circleSmall radius = circlePoints radius 16

-- Displays circle of given radius
-- renderCircle :: (Floating a, Enum a, Vertex (Vertex2 a)) => a -> IO ()
renderCircle r = displayPoints (circle r) LineLoop

-- Displays filled circle of given radius
fillCircle r = displayPoints (circle r) Polygon

-- Displays filled small circle of given radius
fillCircleSmall r = displayPoints (circleSmall r) Polygon

-- Displays filled circle at given point
-- filledCircleAt :: (Vertex (Vertex2 a), Enum a, Floating a) => GLfloat -> GLfloat -> a -> IO ()
filledCircleAt x y r = do
  translate$Vector3 x y (0::GLfloat)
  fillCircle r

-- Displays filled circle at given point
-- filledCircleAtV :: (Vertex (Vertex2 a), Enum a, Floating a) => (GLfloat, GLfloat) -> a -> IO ()
filledCircleAtV (x,y) r = filledCircleAt x y r