<?php

namespace App\System;

use App\Component\SunComponent;

use App\Debug\DebugTextOverlay;

use GL\Math\GLM;

use VISU\ECS\EntitiesInterface;

use VISU\ECS\SystemInterface;

use VISU\Graphics\Rendering\RenderContext;

class TimeOfDaySystem implements SystemInterface

{

/**

* Registers the system, this is where you should register all required components.

*

* @return void

*/

public function register(EntitiesInterface $entities) : void

{

}

/**

* Unregisters the system, this is where you can handle any cleanup.

*

* @return void

*/

public function unregister(EntitiesInterface $entities) : void

{

}

/**

* Updates handler, this is where the game state should be updated.

*

* @return void

*/

public function update(EntitiesInterface $entities) : void

{

// increase the hour of the day

$sun = $entities->getSingleton(SunComponent::class);

$sun->hour += 0.001;

// set sun direction based on the hour

// a day has 24 hours, the hour value is increased continously

// and wont wrap around.

$progress = $sun->hour / 24.0;

$progress = fmod($progress, 1.0);

DebugTextOverlay::debugString(sprintf("Sun Hour: %d Progress: %d", (int)$sun->hour, $progress * 100.0));

// the sun should be at the horizon at 0.25 and 0.75

// and at the top 0.5, meanig < 0.25 and > 0.75 the sun is below the horizon

$angle = $progress * 360.0;

$angle = fmod($angle, 360.0);

$angle -= 90.0;

$sun->direction->x = cos(GLM::radians($angle));

$sun->direction->y = sin(GLM::radians($angle));

$sun->direction->z = 0.0;

// the sun doesnt shine at night, so no diffuse light below the horizon

// but so that we can see something we add a little ambient light

$skyRiseProgress = max(0.0, min(($progress - 0.20) / 0.05, 1.0));

$skySetProgress = max(0.0, min(($progress - 0.70) / 0.05, 1.0));

$skyDiffuse = $progress > 0.5 ? 1 - $skySetProgress : $skyRiseProgress;

$sun->diffuse->x = $skyDiffuse;

$sun->diffuse->y = $skyDiffuse;

$sun->diffuse->z = $skyDiffuse;

DebugTextOverlay::debugString(sprintf("Sky Diffuse: %d", $skyDiffuse * 100.0));

}

/**

* Handles rendering of the scene, here you can attach additional render passes,

* modify the render pipeline or customize rendering related data.

*

* @param RenderContext $context

*/

public function render(EntitiesInterface $entities, RenderContext $context) : void

{

}

}