start porting dash lines from js

- switches to dash units that are scaled by line width
- adds a lineatlas to store patterns line dashed lines
- adds linesdf shader which renders line fill from the lineatlas

js: 8e83d76af3bd877eb9639c02e296363e2c0186f8

1 files changed, 2 insertions, 0 deletions

diff --git a/include/mbgl/map/map.hpp b/include/mbgl/map/map.hpp
index 45846170c2..5d1f576586 100644
--- a/include/mbgl/map/map.hpp
+++ b/include/mbgl/map/map.hpp
@@ -30,6 +30,7 @@ class FileSource;
 class View;
 class GlyphAtlas;
 class SpriteAtlas;
+class LineAtlas;
 
 class Map : private util::noncopyable {
 public:
@@ -182,6 +183,7 @@ private:
     util::ptr<GlyphStore> glyphStore;
     const std::unique_ptr<SpriteAtlas> spriteAtlas;
     util::ptr<Sprite> sprite;
+    const std::unique_ptr<LineAtlas> lineAtlas;
     util::ptr<TexturePool> texturePool;
 
     const std::unique_ptr<Painter> painter;