接上回繼續,做爲一個遊戲引擎,怎能沒有Sprite(精靈)? 下面是基本示例:
const createScene = function () { const scene = new BABYLON.Scene(engine); const camera = new BABYLON.ArcRotateCamera("Camera", -Math.PI / 2, Math.PI / 2, 8, new BABYLON.Vector3(0, 0, 0)); camera.attachControl(canvas, true); const light = new BABYLON.PointLight("Point", new BABYLON.Vector3(5, 10, 5)); // Create a sprite manager // Parameters : name, imgUrl, capacity(最大容量,即樹的總數), cellSize, scene const spriteManagerTrees = new BABYLON.SpriteManager("treesManager", "../assets/img/palm.png", 2000, { width: 512, height: 1024 }); const tree1 = new BABYLON.Sprite("tree", spriteManagerTrees); //注:樹的高寬比例,應該跟cellSize的比例一致,避免失真 tree1.width = 1; tree1.height = 2; tree1.position.y = -0.5; const tree2 = new BABYLON.Sprite("tree2", spriteManagerTrees); tree2.width = 1; tree2.height = 2; tree2.position.x = -1.5; tree2.position.y = 0.8; //逆時針轉45度 tree2.angle = Math.PI / 4; const tree3 = new BABYLON.Sprite("tree3", spriteManagerTrees); tree3.width = 1; tree3.height = 2; tree3.position.x = 1.5; tree3.position.y = 0.8; //順時針轉45度 tree3.angle = -Math.PI / 4; const tree4 = new BABYLON.Sprite("tree4", spriteManagerTrees); tree4.width = 1; tree4.height = 2; tree4.position.x = -1.5; tree4.position.y = -1.5; //垂直翻轉 tree4.invertV = true; const tree5 = new BABYLON.Sprite("tree5", spriteManagerTrees); tree5.width = 1; tree5.height = 2; tree5.position.x = 1.5; tree5.position.y = -1.5; //水平翻轉 tree5.invertU = true; showText(); return scene; } const showText = function () { const ui = BABYLON.GUI.AdvancedDynamicTexture.CreateFullscreenUI("ui"); const text1 = new BABYLON.GUI.TextBlock("t0", "tree1"); const text2 = new BABYLON.GUI.TextBlock("t1", "tree2"); const text3 = new BABYLON.GUI.TextBlock("t2", "tree3"); const text4 = new BABYLON.GUI.TextBlock("t1", "tree4"); const text5 = new BABYLON.GUI.TextBlock("t2", "tree5"); text1.color = 'white'; text2.color = 'white'; text3.color = 'white'; text4.color = 'white'; text5.color = 'white'; text1.top = '-10%'; text2.top = '-27%'; text3.top = '-27%'; text4.top = '4%'; text5.top = '4%'; text1.left = '-0%'; text2.left = '-18%'; text3.left = '18%'; text4.left = '-15%'; text5.left = '15%'; ui.addControl(text1); ui.addControl(text2); ui.addControl(text3); ui.addControl(text4); ui.addControl(text5); }
在線地址: https://yjmyzz.github.io/babylon_js_study/day09/01.html
有1點要注意:
Sprite沒有roration、scaling 這類mesh對象常有的屬性, 要調整Sprite的大小,只能通過width/height來設置,想旋轉/翻轉sprite,可以通過angle、invertV、insertU來控制。
把這顆樹複製一堆,可以模擬出1片小樹林:
const createScene = function () { const scene = new BABYLON.Scene(engine); const camera = new BABYLON.ArcRotateCamera("Camera", -Math.PI / 2, Math.PI / 2, 8, new BABYLON.Vector3(0, 0, 0)); camera.attachControl(canvas, true); const light = new BABYLON.PointLight("Point", new BABYLON.Vector3(5, 10, 5)); // Create a sprite manager // Parameters : name, imgUrl, capacity(最大容量,即樹的總數), cellSize, scene const spriteManagerTrees = new BABYLON.SpriteManager("treesManager", "../assets/img/palm.png", 500, { width: 512, height: 1024 }); //Mutliple trees for (let i = 0; i < 500; i++) { const tree = new BABYLON.Sprite("tree", spriteManagerTrees); tree.width = 1; tree.height = 2; tree.position.x = BABYLON.Scalar.RandomRange(-25, 25); tree.position.z = BABYLON.Scalar.RandomRange(-25, 25); } return scene; }
在線地址: https://yjmyzz.github.io/babylon_js_study/day09/02.html
純靜態的Sprite從效果上看,跟html中的img標籤差不多,只是簡單導入一張圖片而已。Sprite還可以實現類似gif的動畫,比如有下面這張圖:
const spriteManagerUFO = new BABYLON.SpriteManager("ufoManager", "../assets/img/ufo.png", 1, { width: 128, height: 76 }); const ufo = new BABYLON.Sprite("ufo", spriteManagerUFO); ufo.width = 1; ufo.height = 0.5; //playAnimation(from: number, to: number, loop: boolean, delay: number, onAnimationEnd: Nullable<(() => void)>): void ufo.playAnimation(0, 16, true, 125);
在線地址:https://yjmyzz.github.io/babylon_js_study/day09/03.html
其大致原理,就是把ufo.png這張圖,按width:128,height:76 分割成17個cell(單元格),調用 playAnimation 方法時,從0~16(注:下標索引從0開始)依次播放,每1個cell播放的時間間隔爲125ms, 第3個true表示循環播放,詳情可見官方API文檔。
此外,加載圖片時,還能人爲指定加載第幾個cell ,比如下面這張圖,總共有45個cell
下面的代碼演示了,如何加載指定Cell:
const createScene = function () { const scene = new BABYLON.Scene(engine); const camera = new BABYLON.ArcRotateCamera("Camera", -Math.PI / 2, Math.PI / 2, 8, new BABYLON.Vector3(0, 0, 0)); camera.attachControl(canvas, true); const light = new BABYLON.PointLight("Point", new BABYLON.Vector3(5, 10, 5)); const spriteManagerPlayer = new BABYLON.SpriteManager("playerManager", "../assets/img/player.png", 10, 64); const player1 = new BABYLON.Sprite("player1", spriteManagerPlayer); player1.cellIndex=0; player1.position.x = -1; const player2 = new BABYLON.Sprite("player2", spriteManagerPlayer); player2.cellIndex=11; player2.position.x = 0; const player3 = new BABYLON.Sprite("player3", spriteManagerPlayer); player3.cellIndex=44; player3.position.x = 1; const player4 = new BABYLON.Sprite("player4", spriteManagerPlayer); player4.position.y = 1.5; player4.position.x = -0.8; player4.playAnimation(0,40,true,100); const player5 = new BABYLON.Sprite("player5", spriteManagerPlayer); player5.position.y = 1.5; player5.position.x = 0.8; player5.playAnimation(0,9,true,100); return scene; }
在線地址:https://yjmyzz.github.io/babylon_js_study/day09/04.html
最後,綜合運用一把,把UFO、棕櫚樹 加入先前的村莊中
const createScene = function () { const scene = new BABYLON.Scene(engine); const camera = new BABYLON.ArcRotateCamera("camera", -Math.PI / 2, Math.PI / 2.5, 15, new BABYLON.Vector3(0, 0, 0)); camera.upperBetaLimit = Math.PI / 2.2; camera.attachControl(canvas, true); const light = new BABYLON.HemisphericLight("light", new BABYLON.Vector3(1, 1, 0)); const spriteManagerTrees = new BABYLON.SpriteManager("treesManager", "../assets/img/palm.png", 2000, { width: 512, height: 1024 }, scene); //We create trees at random positions for (let i = 0; i < 200; i++) { const tree = new BABYLON.Sprite("tree", spriteManagerTrees); tree.position.x = Math.random() * (-30); tree.position.z = Math.random() * 20 + 8; tree.position.y = 0.5; } for (let i = 0; i < 200; i++) { const tree = new BABYLON.Sprite("tree", spriteManagerTrees); tree.position.x = Math.random() * (25) + 7; tree.position.z = Math.random() * -35 + 8; tree.position.y = 0.5; } //Skybox const skybox = BABYLON.MeshBuilder.CreateBox("skyBox", { size: 150 }, scene); const skyboxMaterial = new BABYLON.StandardMaterial("skyBox", scene); skyboxMaterial.backFaceCulling = false; skyboxMaterial.reflectionTexture = new BABYLON.CubeTexture("../assets/img/sky/skybox", scene); skyboxMaterial.reflectionTexture.coordinatesMode = BABYLON.Texture.SKYBOX_MODE; skyboxMaterial.diffuseColor = new BABYLON.Color3(0, 0, 0); skyboxMaterial.specularColor = new BABYLON.Color3(0, 0, 0); skybox.material = skyboxMaterial; BABYLON.SceneLoader.ImportMeshAsync("", "../assets/glb/", "valleyvillage.glb"); const spriteManagerUFO = new BABYLON.SpriteManager("ufoManager", "../assets/img/ufo.png", 1, { width: 128, height: 76 }); const ufo = new BABYLON.Sprite("ufo", spriteManagerUFO); ufo.width = 1; ufo.height = 0.5; ufo.position.y = 5; ufo.position.x = 3; ufo.position.z = 2; //playAnimation(from: number, to: number, loop: boolean, delay: number, onAnimationEnd: Nullable<(() => void)>): void ufo.playAnimation(0, 16, true, 125); return scene; }
在線地址:https://yjmyzz.github.io/babylon_js_study/day09/05.html
參考文檔:
https://doc.babylonjs.com/features/featuresDeepDive/sprites/sprite_manager
https://doc.babylonjs.com/features/introductionToFeatures/chap5/trees