Game feels laggy

[alcalyn]

As soon as we are on a big map with few units, game already feels laggy when dragging it.

We should be able to drag map on bigger-than-big maps without any lags.

[Greegko]

I have the same issue even when not doing anything with the game, just leaving on the screen.
The root cause is GPU 100% used by react-svg-pan-zoom lib, autoPanLoop requestAnimationFrame event calls which makes the whole thing to rerender every x ms.
I was mistaken, the issue is react-hexgrid with <image /> as content. If you comment out the

openhex/src/components/Game/HexCell.js

Lines 54 to 61 in 48bd262

	<image
	x={-10}
	y={-10}
	width={20}
	height={20}
	xlinkHref={Themes.getImageFor(hex.entity)}
	className={this.hexContentClasses(hex)}
	/>

part it won't use the GPU almost at all.

To be more precise, the SVG filter on the image cause that much GPU usage, this beauty:

openhex/src/components/Game/OpenHexGrid.js

Lines 199 to 207 in 5fae912

	<filter id="gold-highlight" x="-200%" y="-200%" width="400%" height="400%">
	<feGaussianBlur id="gold-shadow" in="SourceAlpha" stdDeviation="2" result="blur"/>
	<feFlood floodColor="#FFFF00" result="offsetColor"/>
	<feComposite in="offsetColor" in2="blur" operator="in" result="offsetBlur"/>
	<feMerge>
	<feMergeNode in="offsetBlur"/>
	<feMergeNode in="SourceGraphic"/>
	</feMerge>
	</filter>