Babylon js SpriteManager with LogarithmicDepth support

SpriteManager.js

class SpriteManager extends BABYLON.SpriteManager {

	constructor(...args) {
		super(...args);

		if (!BABYLON.Effect.ShadersStore.spritesDepthVertexShader) {
			SpriteManager.init();
		}

		// Effects
		this._effectBase = this._scene.getEngine().createEffect("spritesDepth",
			[BABYLON.VertexBuffer.PositionKind, "options", "cellInfo", BABYLON.VertexBuffer.ColorKind],
			["view", "projection", "textureInfos", "alphaTest"],
			["diffuseSampler"], "");
	}

	render() {

		// Check
		if (!this._effectBase.isReady() || !this._effectFog.isReady() || !this._spriteTexture || !this._spriteTexture.isReady()) {
			return;
		}

		var engine = this._scene.getEngine();
		var baseSize = this._spriteTexture.getBaseSize();

		// Sprites
		var deltaTime = engine.getDeltaTime();
		var max = Math.min(this._capacity, this.sprites.length);
		var rowSize = baseSize.width / this.cellWidth;

		var offset = 0;
		for (var index = 0; index < max; index++) {
			var sprite = this.sprites[index];
			if (!sprite) {
				continue;
			}

			sprite._animate(deltaTime);

			this._appendSpriteVertex(offset++, sprite, 0, 0, rowSize);
			this._appendSpriteVertex(offset++, sprite, 1, 0, rowSize);
			this._appendSpriteVertex(offset++, sprite, 1, 1, rowSize);
			this._appendSpriteVertex(offset++, sprite, 0, 1, rowSize);
		}

		this._buffer.update(this._vertexData);

		// Render
		var effect = this._effectBase;

		if (this._scene.fogEnabled && this._scene.fogMode !== Scene.FOGMODE_NONE && this.fogEnabled) {
			effect = this._effectFog;
		}

		engine.enableEffect(effect);

		var viewMatrix = this._scene.getViewMatrix();
		effect.setTexture('diffuseSampler', this._spriteTexture);
		effect.setMatrix('view', viewMatrix);
		effect.setMatrix('projection', this._scene.getProjectionMatrix());

		effect.setFloat2('textureInfos', this.cellWidth / baseSize.width, this.cellHeight / baseSize.height);

		// Fog
		if (this._scene.fogEnabled && this._scene.fogMode !== Scene.FOGMODE_NONE && this.fogEnabled) {
			effect.setFloat4("vFogInfos", this._scene.fogMode, this._scene.fogStart, this._scene.fogEnd, this._scene.fogDensity);
			effect.setColor3("vFogColor", this._scene.fogColor);
		}

		// Log. depth
		effect.setFloat('logarithmicDepthConstant', 2.0 / (Math.log(this._scene.activeCamera.maxZ + 1.0) / Math.LN2));

		// VBOs
		engine.bindBuffers(this._vertexBuffers, this._indexBuffer, effect);

		// Draw order
		engine.setDepthFunctionToLessOrEqual();
		effect.setBool('alphaTest', true);
		engine.setColorWrite(false);
		engine.draw(true, 0, max * 6);
		engine.setColorWrite(true);
		effect.setBool('alphaTest', false);

		engine.setAlphaMode(BABYLON.Engine.ALPHA_COMBINE);
		engine.draw(true, 0, max * 6);
		engine.setAlphaMode(BABYLON.Engine.ALPHA_DISABLE);
	}

	// Need to be called once
	static init() {
		BABYLON.Effect.ShadersStore.spritesDepthVertexShader = "attribute vec4 position;\nattribute vec4 options;\nattribute vec4 cellInfo;\nattribute vec4 color;\n\nuniform vec2 textureInfos;\nuniform mat4 view;\nuniform mat4 projection;\n\nvarying vec2 vUV;\nvarying vec4 vColor;\n#include<fogVertexDeclaration>\nuniform float logarithmicDepthConstant;\nvarying float vFragmentDepth;\nvoid main(void) { \nvec3 viewPos=(view*vec4(position.xyz,1.0)).xyz; \nvec2 cornerPos;\nfloat angle=position.w;\nvec2 size=vec2(options.x,options.y);\nvec2 offset=options.zw;\nvec2 uvScale=textureInfos.xy;\ncornerPos=vec2(offset.x-0.5,offset.y-0.5)*size;\n\nvec3 rotatedCorner;\nrotatedCorner.x=cornerPos.x*cos(angle)-cornerPos.y*sin(angle);\nrotatedCorner.y=cornerPos.x*sin(angle)+cornerPos.y*cos(angle);\nrotatedCorner.z=0.;\n\nviewPos+=rotatedCorner;\ngl_Position=projection*vec4(viewPos,1.0); \nvFragmentDepth = 1.0 + gl_Position.w;\ngl_Position.z = log2(max(0.000001, vFragmentDepth)) * logarithmicDepthConstant;\n\nvColor=color;\n\nvec2 uvOffset=vec2(abs(offset.x-cellInfo.x),1.0-abs(offset.y-cellInfo.y));\nvUV=(uvOffset+cellInfo.zw)*uvScale;\n\n#ifdef FOG\nvFogDistance=viewPos;\n#endif\n}";
		BABYLON.Effect.ShadersStore.spritesDepthPixelShader = "uniform bool alphaTest;\nvarying vec4 vColor;\n#extension GL_EXT_frag_depth : enable\nuniform float logarithmicDepthConstant;\nvarying float vFragmentDepth;\n\nvarying vec2 vUV;\nuniform sampler2D diffuseSampler;\n\n#include<fogFragmentDeclaration>\nvoid main(void) {\nvec4 color=texture2D(diffuseSampler,vUV);\nif (alphaTest) \n{\nif (color.a<0.95)\ndiscard;\n}\ncolor*=vColor;\n#include<fogFragment>\ngl_FragDepthEXT = log2(vFragmentDepth) * logarithmicDepthConstant * 0.5;\ngl_FragColor=color;\n}";
	}
}