MBHaxe/src/shaders/CubemapRenderer.hx

package shaders;

import src.Sky;
import h3d.Vector;
import h3d.scene.Scene;
import h3d.Engine;
import h3d.Camera;
import src.MarbleGame;
import h3d.mat.Texture;

class CubemapRenderer {
	public var cubemap:Texture;
	public var sky:Sky;
	public var position:Vector;

	var camera:Camera;
	var scene:Scene;
	var nextFaceToRender:Int;

	public function new(scene:Scene, sky:Sky) {
		this.scene = scene;
		this.sky = sky;
		this.cubemap = new Texture(128, 128, [Cube, Dynamic, Target], h3d.mat.Data.TextureFormat.RGB8);
		this.cubemap.depthBuffer = new h3d.mat.DepthBuffer(128, 128, h3d.mat.DepthBuffer.DepthFormat.Depth24);
		this.camera = new Camera(90, 1, 1, 0.02, scene.camera.zFar);
		this.position = new Vector();
		this.nextFaceToRender = 0;
	}

	public function render(e:Engine, budget:Float = 1e8) {
		var scenecam = scene.camera;
		scene.camera = camera;

		var start = haxe.Timer.stamp();
		var renderedFaces = 0;

		for (i in 0...6) {
			var index = (nextFaceToRender + i) % 6;

			e.pushTarget(cubemap, index);
			this.camera.setCubeMap(index, position);
			e.clear(0, 1);
			scene.render(e);
			e.popTarget();

			renderedFaces++;
			var time = haxe.Timer.stamp();
			var elapsed = time - start;
			var elapsedPerFace = elapsed / renderedFaces;

			if (elapsedPerFace * (renderedFaces + 1) >= budget)
				break;
		}
		scene.camera = scenecam;

		this.nextFaceToRender += renderedFaces;
		this.nextFaceToRender %= 6;
	}

	public function getCameraFrustums() {
		var frustums = [];
		var prevFar = this.camera.zFar;
		this.camera.zFar = 300; // Max draw distance
		for (i in 0...6) {
			this.camera.setCubeMap(i, position);
			this.camera.update();
			frustums.push(camera.frustum.clone());
		}
		this.camera.zFar = prevFar;
		return frustums;
	}
}