Add fine-grain grid when selection is active

1 files changed, 15 insertions, 0 deletions

diff --git a/src/Chelleport/Draw.hs b/src/Chelleport/Draw.hs
index 4ee5b31..1c23ee0 100644
--- a/src/Chelleport/Draw.hs
+++ b/src/Chelleport/Draw.hs
@@ -2,6 +2,7 @@ module Chelleport.Draw where
 
 import Chelleport.Types
 import Data.Text (Text)
+import qualified Data.Vector.Storable as Vector
 import Data.Word (Word8)
 import Foreign.C (CInt)
 import qualified SDL
@@ -34,6 +35,9 @@ colorAxisLines = colorAccent
 colorBackground :: SDL.V4 Word8
 colorBackground = SDL.V4 15 12 25 0
 
+colorFineGrainGrid :: SDL.V4 Word8
+colorFineGrainGrid = SDL.V4 55 52 65 100
+
 drawText :: DrawContext -> SDL.V2 CInt -> SDL.V4 Word8 -> Text -> IO (CInt, CInt)
 drawText ctx@(DrawContext {ctxRenderer = renderer}) position color text = do
   surface <- TTF.blended (ctxFont ctx) color text
@@ -64,3 +68,14 @@ drawVerticalLine :: DrawContext -> CInt -> IO ()
 drawVerticalLine ctx@(DrawContext {ctxRenderer = renderer}) x = do
   (SDL.V2 _width height) <- windowSize ctx
   SDL.drawLine renderer (SDL.P $ SDL.V2 x 0) (SDL.P $ SDL.V2 x height)
+
+drawCircle :: DrawContext -> Int -> (CInt, CInt) -> IO ()
+drawCircle (DrawContext {ctxRenderer = renderer}) radius (x, y) = do
+  let renderedPoints = radius * 7
+  let toTheta n = fromIntegral n * (2 * pi) / fromIntegral renderedPoints
+  let toPointOnCircle n =
+        SDL.V2
+          (x + round ((fromIntegral radius :: Float) * cos (toTheta n)))
+          (y + round ((fromIntegral radius :: Float) * sin (toTheta n)))
+  let points = Vector.generate renderedPoints (SDL.P . toPointOnCircle)
+  SDL.drawPoints renderer points