Polygon style render

[eliasku]

Change regular quad sprites to textured polygons. Will enable better Z-buffer utilisation in the game world render pass. To make polygon-like sprites (mesh sprites) we could use html page to edit sprite contours and export emoji source + contours data. Then in runtime we able to triangulate mesh with ear-cut library.

Notes:

• Potentially we could generate couple of LOD levels and select one depends on camera zoom
• Maybe better at first to do ear-cut triangulation offline
• Maybe alpha cut threshold should be 0
• Polygon edges potentially could be antialiased with regular MSAA in future

[eliasku]

Approach successfully proven that old Galaxy A7 device FPS grows from 27 to 60.

Polygon-styled emoji looks bad on that low-res, so I decide to mirror current style with hard-edge marching. In addition we need to round resulted positions on hard-edge triangulation.

Flood-fill is applied to remove black thread artefacts on mesh edges for low-res / MSAA modes.

Next steps

• Game loading progress bar would be nice. Now we download images and mesh data from files.
• Clear quad now fills all screen with depth-test, we could split that to rects which are not overlapped by land and reduce clear pass in general.
• Fog render fills the whole screen, we could set 2nd texture as lighting and render land and game objects using fragment shader with lighting enabled
• Remove Virtual joysticks from atlas. That now could be drawn with mesh-primitives + dynamic text