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使用 Three.js 绘制纹理

发布于 2025-01-20 09:20:38 字数 103 浏览 3 评论 0原文

纹理泼溅可以与 Three.js 或其他 Javascript 3D 渲染框架一起使用吗？如果是的话，我想看看示例，甚至是大地形上的教程。如果它不起作用，还有其他方法绘制大地形图吗？谢谢。

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指尖凝香 2025-01-27 09:20:38

已接受的挑战！

首先，您可以编写一个灰度图像并将其用作高度图的顶点着色器，并包含不同的浮点（称为vamount）以传递到片段着色器以确定纹理（s）在这一点上显示（混合）。

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 );
}

接下来是片段着色器，它可以包括不同的高程所需的许多纹理，并且有一个很棒的内置功能，称为smookestep，使平滑过渡更易于计算。

这样的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, 0.0, 1.0) + water + sandy + grass + rocky + snowy;
}

然后，您可以使用trex.shadermaterial将其用于给定的网格。以上代码在

这可以帮助您入门。愉快的编码！

Challenge accepted!

First, you can write a vertex shader that takes a grayscale image and uses it as a heightmap, and includes a varying float (called vAmount below) to pass to the fragment shader to determine the texture(s) to display(blend) at that point.

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 );
}

Next comes the fragment shader, which can include however many textures you need for different elevations, and there is a great built-in function called smoothstep that makes smooth transitions much easier to calculate.

An example of code for such a fragment shader:

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, 0.0, 1.0) + water + sandy + grass + rocky + snowy;
}

Then you can use a THREE.ShaderMaterial to use this for a given mesh. The above code is implemented at http://stemkoski.github.io/Three.js/Shader-Heightmap-Textures.html and produces a result like this:

enter image description here