BabylonJS - 光照

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本章我们将学习 BabylonJS 中使用的光照。我们将首先了解 BabylonJS 提供的不同类型的灯光。

光照旨在产生每个像素接收的漫反射和镜面反射颜色。之后，它用于材质以获得每个像素的最终颜色。

BabylonJS 提供 4 种类型的灯光。

  • 点光源
  • 方向光
  • 聚光灯
  • 半球光

BabylonJS - 点光源

点光源的经典例子是太阳，它的光线向四面八方散射。点光源在空间中有一个独特的点，从该点向各个方向散射光线。可以使用镜面反射和漫反射属性来控制光线颜色。

语法

以下是点光源的语法：

var light0 = new BABYLON.PointLight("Omni0", new BABYLON.Vector3(1, 10, 1), scene);

点光源有三个不同的参数：

  • 第一个参数是光源的名称。

  • 第二个参数是放置点光源的位置。

  • 第三个参数是需要附加光源的场景。

以下属性用于在上面创建的对象上添加颜色：

light0.diffuse = new BABYLON.Color3(1, 0, 0);
light0.specular = new BABYLON.Color3(1, 1, 1);

演示

<!doctype html>
<html>
   <head>
      <meta charset = "utf-8">
      <title>BabylonJs - Basic Element-Creating Scene</title>
      <script src = "babylon.js"></script>
      <style>
         canvas {width: 100%; height: 100%;}
      </style>
   </head>

   <body>
      <canvas id = "renderCanvas"></canvas>
      <script type = "text/javascript">
         var canvas = document.getElementById("renderCanvas");
         var engine = new BABYLON.Engine(canvas, true);
         var createScene  = function() {
            var scene = new BABYLON.Scene(engine);
            scene.clearColor = new BABYLON.Color3( .5, .5, .5);
            
            var camera = new BABYLON.ArcRotateCamera("camera1",  0, 0, 0, new BABYLON.Vector3(0, 0, -0), scene);
            camera.setPosition(new BABYLON.Vector3(0, 0, -100));
            camera.attachControl(canvas, true);
            
            var pl = new BABYLON.PointLight("pl", new BABYLON.Vector3(1, 20, 1), scene);
            pl.diffuse = new BABYLON.Color3(0, 1, 0);
            pl.specular = new BABYLON.Color3(1, 0, 0);
            
            var ground = BABYLON.Mesh.CreateGround("ground", 150, 6, 2, scene);
            return scene;
         };
         var scene = createScene();
         engine.runRenderLoop(function() {
            scene.render();
         });
      </script>
   </body>
</html>

输出

Pointlight

BabylonJS - 方向光

在方向光中，光线由方向定义，并根据放置位置向各个方向发射。

var light0 = new BABYLON.DirectionalLight("Dir0", new BABYLON.Vector3(0, -1, 0), scene);

点光源有三个不同的参数：

  • 第一个参数是光源的名称。

  • 第二个参数是位置。现在，它在 Y 轴上放置为负 -1。

  • 第三个参数是要附加的场景。

在这里，您可以使用镜面反射和漫反射属性添加颜色。

light0.diffuse = new BABYLON.Color3(0, 1, 0);
light0.specular = new BABYLON.Color3(1,0, 0);

演示

<!doctype html>
<html>
   <head>
      <meta charset = "utf-8">
      <title>BabylonJs - Basic Element-Creating Scene</title>
      <script src = "babylon.js"></script>
      <style>
         canvas {width: 100%; height: 100%;}
      </style>
   </head>

   <body>
      <canvas id = "renderCanvas"></canvas>
      <script type = "text/javascript">
         var canvas = document.getElementById("renderCanvas");
         var engine = new BABYLON.Engine(canvas, true);
         var createScene  = function() {
            var scene = new BABYLON.Scene(engine);
            scene.clearColor = new BABYLON.Color3( .5, .5, .5);
            
            var camera = new BABYLON.ArcRotateCamera("camera1",  0, 0, 0, new BABYLON.Vector3(0, 0, -0), scene);
            camera.setPosition(new BABYLON.Vector3(0, 0, -100));
            camera.attachControl(canvas, true);
            
            var pl = new BABYLON.DirectionalLight("Dir0", new BABYLON.Vector3(0, -10, 0), scene);
            pl.diffuse = new BABYLON.Color3(0, 1, 0);
            pl.specular = new BABYLON.Color3(1, 0, 0);
            
            var ground = BABYLON.Mesh.CreateGround("ground", 150, 6, 2, scene);
            return scene;
         };
         var scene = createScene();
         engine.runRenderLoop(function() {
            scene.render();
         });
      </script>
   </body>
</html>

输出

以上代码行生成以下输出：

Directional Light

BabylonJS - 聚光灯

聚光灯就像锥形的光线。

语法

以下是聚光灯的语法：

var light0 = new BABYLON.SpotLight("Spot0", new BABYLON.Vector3(0, 30, -10), new BABYLON.Vector3(0, -1, 0), 0.8, 2, scene);

点光源有五个不同的参数：

  • 第一个参数是光源的名称。
  • 第二个参数是位置。
  • 第三个参数是方向。
  • 第四个参数是角度。
  • 第五个参数是指数。

这些值定义了一个从位置开始，朝向方向发射的锥形光线。镜面反射和漫反射用于控制光线颜色。

light0.diffuse = new BABYLON.Color3(1, 0, 0);
light0.specular = new BABYLON.Color3(1, 1, 1);

演示

<!doctype html>
<html>
   <head>
      <meta charset = "utf-8">
      <title>BabylonJs - Basic Element-Creating Scene</title>
      <script src = "babylon.js"></script>
      <style>
         canvas {width: 100%; height: 100%;}
      </style>
   </head>

   <body>
      <canvas id = "renderCanvas"></canvas>
      <script type = "text/javascript">
         var canvas = document.getElementById("renderCanvas");
         var engine = new BABYLON.Engine(canvas, true);
         var createScene  = function() {
            var scene = new BABYLON.Scene(engine);
            scene.clearColor = new BABYLON.Color3( .5, .5, .5);
            
            var camera = new BABYLON.ArcRotateCamera("camera1",  0, 0, 0, new BABYLON.Vector3(0, 0, -0), scene);
            camera.setPosition(new BABYLON.Vector3(0, 0, -100));
            camera.attachControl(canvas, true);
            
            var light0 = new BABYLON.SpotLight("Spot0", new BABYLON.Vector3(0, 30, -10), new BABYLON.Vector3(0, -1, 0), 0.8, 2, scene);
            light0.diffuse = new BABYLON.Color3(0, 1, 0);
            light0.specular = new BABYLON.Color3(1, 0, 0);
            
            var ground = BABYLON.Mesh.CreateGround("ground", 80,80, 2, scene);
            return scene;
         };
         var scene = createScene();
         engine.runRenderLoop(function() {
            scene.render();
         });
      </script>
   </body>
</html>

输出

以上代码行生成以下输出：

Spot Light

BabylonJS - 半球光

半球光更像是获取环境光。光线方向朝向天空。光线赋予三种颜色；一种用于天空，一种用于地面，最后一种用于镜面反射。

语法

以下是半球光的语法：

var light0 = new BABYLON.HemisphericLight("Hemi0", new BABYLON.Vector3(0, 1, 0), scene);

颜色

light0.diffuse = new BABYLON.Color3(1, 0, 0);
light0.specular = new BABYLON.Color3(0, 1, 0);
light0.groundColor = new BABYLON.Color3(0, 0, 0);

演示

<!doctype html>
<html>
   <head>
      <meta charset = "utf-8">
      <title>BabylonJs - Basic Element-Creating Scene</title>
      <script src = "babylon.js"></script>
      <style>
         canvas {width: 100%; height: 100%;}
      </style>
   </head>

   <body>
      <canvas id = "renderCanvas"></canvas>
      <script type = "text/javascript">
         var canvas = document.getElementById("renderCanvas");
         var engine = new BABYLON.Engine(canvas, true);
         var createScene  = function() {
            var scene = new BABYLON.Scene(engine);
            scene.clearColor = new BABYLON.Color3( .5, .5, .5);
            
            var camera = new BABYLON.ArcRotateCamera("camera1",  0, 0, 0, new BABYLON.Vector3(0, 0, -0), scene);
            camera.setPosition(new BABYLON.Vector3(0, 0, -100));
            camera.attachControl(canvas, true);
            
            var light0 = new BABYLON.HemisphericLight("Hemi0", new BABYLON.Vector3(0, 1, 0), scene);
            light0.diffuse = new BABYLON.Color3(1, 0, 0);
            light0.specular = new BABYLON.Color3(0, 1, 0);
            light0.groundColor = new BABYLON.Color3(0, 0, 0);
            
            var ground = BABYLON.Mesh.CreateGround("ground", 100,100, 2, scene);
            return scene;
         };
         var scene = createScene();
         engine.runRenderLoop(function() {
            scene.render();
         });
      </script>
   </body>
</html>

输出

以上代码行生成以下输出：

Hemispheric Light
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