html5 – 使用Three.js进行纹理喷涂

纹理splatting是否适用于Three.js或其他 Javascript 3D渲染框架？如果是的话,我想看一些例子,甚至可以在大地形上进行教程.如果它不起作用是否有任何其他方式映射大地形？
谢谢.

解决方法

接受挑战！

首先,您可以编写一个顶点着色器,它采用灰度图像并将其用作高度图,并包含一个变化的浮点(下面称为vAmount),以传递给片段着色器以确定要在其处显示(混合)的纹理.点.

uniform sampler2D bumpTexture;
uniform float bumpScale;

varying float vAmount;
varying vec2 vUV;

void main() 
{
    vUV = uv;
    vec4 bumpData = texture2D( bumpTexture,uv );

    vAmount = bumpData.r; // assuming map is grayscale it doesn't matter if you use r,g,or b.

    // move the position along the normal
    vec3 newPosition = position + normal * bumpScale * vAmount;

    gl_Position = projectionMatrix * modelViewMatrix * vec4( newPosition,1.0 );
}

接下来是碎片着色器,它可以包含不同高程所需的许多纹理,并且有一个很棒的内置函数,称为smoothstep,它使得平滑过渡更容易计算.

这种片段着色器的代码示例：

uniform sampler2D oceanTexture;
uniform sampler2D sandyTexture;
uniform sampler2D grasstexture;
uniform sampler2D rockyTexture;
uniform sampler2D sNowyTexture;

varying vec2 vUV;

varying float vAmount;

void main() 
{
    vec4 water = (smoothstep(0.01,0.25,vAmount) - smoothstep(0.24,0.26,vAmount)) * texture2D( oceanTexture,vUV * 10.0 );
    vec4 sandy = (smoothstep(0.24,0.27,vAmount) - smoothstep(0.28,0.31,vAmount)) * texture2D( sandyTexture,vUV * 10.0 );
    vec4 grass = (smoothstep(0.28,0.32,vAmount) - smoothstep(0.35,0.40,vAmount)) * texture2D( grasstexture,vUV * 20.0 );
    vec4 rocky = (smoothstep(0.30,0.50,vAmount) - smoothstep(0.40,0.70,vAmount)) * texture2D( rockyTexture,vUV * 20.0 );
    vec4 sNowy = (smoothstep(0.50,0.65,vAmount))                                   * texture2D( sNowyTexture,vUV * 10.0 );
    gl_FragColor = vec4(0.0,0.0,1.0) + water + sandy + grass + rocky + sNowy;
}

然后,您可以使用THREE.ShaderMaterial将其用于给定网格.上面的代码在http://stemkoski.github.io/Three.js/Shader-Heightmap-Textures.html实现,产生如下结果：

希望这有助于您入门.快乐的编码！