[suggestion] multi-material mixing

[jcyuan]

yes this question is being up again and again, but this still makes me scratch head all day.
I think this should have a common solution and be built into the standard official lib.
for example like BABYLONJS does:
let t = new TerrainMaterial(); t.mixMap = xxxx use rgb to mix 3 maps t.map1 = xxxx t.map2 = xxxx t.map3 = xxxx t.normal1 = xxxx t.normal2 = xxxx t.normal3 = xxxx
although we can write a shader to solve this, but it's really hard (for guys not famililar to shader like me), my scene has fog / hemispherelight / drlight / dithering etc which means I need to "#include <a lot of other parts>" to my shader but I don't quite understand of THREEJS's shader system. (I found i need to write some "#define USE_XXX" once I use #include??)
anyway my shader not work.

what do you guys think?

[jcyuan]

THREE version: r87

[jcyuan]

or there some shaders available?
repeat + map + normal + mix + light + shadow

[WestLangley]

I suppose you are referring to this.

See this SO post about texture splatting.

Also, perhaps you can use THREE.NodeMaterial. See webgl_materials_nodes.html.

[jcyuan]

thanks for the reply @WestLangley , yes I'm referring to that article.
and the post link you sent I had read it already, that is just a basic mixing without normal and light etc.
when I tried to add these missing features by using the built in shader e.g. #include <shadowmap_frags> it won't work...
I'll look into what NodeMaterials is.

[Mugen87]

Actually it would be nice to have a simple texture splatting example (similar to babylon.js) in the repo. Maybe a materials / texture / splatting?

[makc]

although we can write a shader to solve this, but it's really hard (for guys not famililar to shader like me)

writing shaders is not hard, writing good shaders is hard. it's just like with js, once you learn glsl your only limit is your talent. and glsl is in a way simpler than javascript. cheers!

[jcyuan]

ok things are sorted.
i wrote a working one, but need some guy to optimise the part of textures mixing (see comment below), i believe that the current part is not good enough.

import * as THREE from 'three';

export class TerrainMaterial extends THREE.ShaderMaterial {

    public constructor() {

        super({
            uniforms: THREE.UniformsUtils.merge([
                THREE.UniformsLib.fog,
                THREE.UniformsLib.lights,
                {
                    diffuse: { value: new THREE.Color(0xeeeeee) },
                    opacity: { value: 1.0 },
                    emissive: { value: new THREE.Color(0x000000) },
                    specular: { value: new THREE.Color(0x111111) },
                    shininess: { value: 0 },

                    offsetRepeat: { value: new THREE.Vector4(0, 0, 1, 1) },

                    map1: { value: null },
                    map2: { value: null },
                    map3: { value: null },
                    map1Normal: { value: null },
                    map2Normal: { value: null },
                    map3Normal: { value: null },
                    map1HeightRange: { value: 0 },
                    map2HeightRange: { value: 0 },
                    map3HeightRange: { value: 0 }
                }
            ]),
            vertexShader: [
                "varying vec3 vNormal;",
                "varying vec3 vViewPosition;",
                "varying vec3 fPosition;",

                "varying vec2 vUv;",
                "uniform vec4 offsetRepeat;",

                THREE.ShaderChunk.shadowmap_pars_vertex,
                //THREE.ShaderChunk.logdepthbuf_pars_vertex,
                THREE.ShaderChunk.fog_pars_vertex,

                "void main(){",
                    THREE.ShaderChunk.beginnormal_vertex,
                    THREE.ShaderChunk.defaultnormal_vertex,
                    "vUv = uv * offsetRepeat.zw + offsetRepeat.xy;",
                    "vNormal = normalize( transformedNormal );",
                    THREE.ShaderChunk.begin_vertex,
                    THREE.ShaderChunk.project_vertex,
                    //THREE.ShaderChunk.logdepthbuf_vertex,
                    "fPosition = position;",
                    "vViewPosition = - mvPosition.xyz;",
                    THREE.ShaderChunk.worldpos_vertex,
                    THREE.ShaderChunk.shadowmap_vertex,
                    THREE.ShaderChunk.fog_vertex,
                "}"
            ].join("\n"),
            fragmentShader: [
                "uniform vec3 diffuse;",
                "uniform vec3 emissive;",
                "uniform vec3 specular;",
                "uniform float shininess;",
                "uniform float opacity;",

                "uniform sampler2D map1;",
                "uniform sampler2D map2;",
                "uniform sampler2D map3;",
                "uniform sampler2D map1Normal;",
                "uniform sampler2D map2Normal;",
                "uniform sampler2D map3Normal;",
                "uniform float map1HeightRange;",
                "uniform float map2HeightRange;",
                "uniform float map3HeightRange;",
                
                "varying vec2 vUv;",
                "varying vec3 fPosition;",

                THREE.ShaderChunk.common,
                THREE.ShaderChunk.packing,
                THREE.ShaderChunk.dithering_pars_fragment,
                THREE.ShaderChunk.emissivemap_pars_fragment,
                THREE.ShaderChunk.fog_pars_fragment,
                THREE.ShaderChunk.bsdfs,
                THREE.ShaderChunk.lights_pars,
                THREE.ShaderChunk.lights_phong_pars_fragment,
                THREE.ShaderChunk.shadowmap_pars_fragment,
                THREE.ShaderChunk.specularmap_pars_fragment,
                //THREE.ShaderChunk.logdepthbuf_pars_fragment,
                "vec3 perturbNormal2Arb( vec3 normalColor, vec3 eye_pos, vec3 surf_norm ) {",
                    "vec3 q0 = vec3( dFdx( eye_pos.x ), dFdx( eye_pos.y ), dFdx( eye_pos.z ) );",
                    "vec3 q1 = vec3( dFdy( eye_pos.x ), dFdy( eye_pos.y ), dFdy( eye_pos.z ) );",
                    "vec2 st0 = dFdx( vUv.st );",
                    "vec2 st1 = dFdy( vUv.st );",
                    "vec3 S = normalize( q0 * st1.t - q1 * st0.t );",
                    "vec3 T = normalize( -q0 * st1.s + q1 * st0.s );",
                    "vec3 N = normalize( surf_norm );",
                    "vec3 mapN = normalColor * 2.0 - 1.0;",
                    //"mapN.xy = normalScale * mapN.xy;",
                    "mat3 tsn = mat3( S, T, N );",
                    "return normalize( tsn * mapN );",
                "}",
                "void main(){",
                    "vec4 diffuseColor = vec4( diffuse, opacity );",
                    "ReflectedLight reflectedLight = ReflectedLight( vec3( 0.0 ), vec3( 0.0 ), vec3( 0.0 ), vec3( 0.0 ) );",
                    "vec3 totalEmissiveRadiance = emissive;",
                    //THREE.ShaderChunk.logdepthbuf_fragment,

                    "vec3 texel;",
                    "vec3 texelNormal;",
                    "float amount;",
                    
                    //need to optimize here, let's say remove if else if else?
                    "if(fPosition.y < map1HeightRange){",
                        "texel = texture2D(map1, vUv).rgb;",
                        "texelNormal = texture2D(map1Normal, vUv).rgb;",
                    "}",
                    "else if(fPosition.y < map2HeightRange){",
                        "amount = (fPosition.y - map1HeightRange) / map1HeightRange;",
                        "texel = mix(texture2D(map1, vUv), texture2D(map2, vUv), amount).rgb;",
                        "texelNormal = mix(texture2D(map1Normal, vUv), texture2D(map2Normal, vUv), amount).rgb;",
                    "}",
                    "else if(fPosition.y < map3HeightRange){",
                        "float hStep = map3HeightRange - map2HeightRange;",
                        "amount = (fPosition.y - hStep) / hStep;",
                        "texel = mix(texture2D(map2, vUv), texture2D(map3, vUv), amount).rgb;",
                        "texelNormal = mix(texture2D(map2Normal, vUv), texture2D(map3Normal, vUv), amount).rgb;",
                    "} else {",
                        "texel = texture2D(map3, vUv).rgb;",
                        "texelNormal = texture2D(map3Normal, vUv).rgb;",
                    "}",

                    "vec4 texelColor = vec4( texel, 1.0 );",
                    "texelColor = mapTexelToLinear( texelColor );",

                    "diffuseColor *= texelColor;",

                    THREE.ShaderChunk.specularmap_fragment,
                    "vec3 normal = normalize( vNormal );",
                    "normal = perturbNormal2Arb( texelNormal.rgb, -vViewPosition, normal );",

                    THREE.ShaderChunk.emissivemap_fragment,
                    THREE.ShaderChunk.lights_phong_fragment,
                    THREE.ShaderChunk.lights_template,
                    "vec3 outgoingLight = reflectedLight.directDiffuse + reflectedLight.indirectDiffuse + reflectedLight.directSpecular + reflectedLight.indirectSpecular + totalEmissiveRadiance;",
                    "gl_FragColor = vec4( outgoingLight, diffuseColor.a );",
                    THREE.ShaderChunk.tonemapping_fragment,
                    THREE.ShaderChunk.encodings_fragment,
                    THREE.ShaderChunk.fog_fragment,
                    THREE.ShaderChunk.premultiplied_alpha_fragment,
                    THREE.ShaderChunk.dithering_fragment,
                "}"
            ].join("\n")
        });

        this.defaultAttributeValues = null;

        this.fog = true;
        this.lights = true;

        this.extensions.derivatives = true;
        this.extensions.shaderTextureLOD = true;
    }

    public setOffsetRepeat(ofX: number, ofY: number, rpX: number, rpY: number):void {
        this.uniforms["offsetRepeat"].value.set(ofX, ofY, rpX, rpY);
        this.setRepeat(this.uniforms["map1"].value, this.uniforms["map1Normal"].value);
        this.setRepeat(this.uniforms["map2"].value, this.uniforms["map2Normal"].value);
        this.setRepeat(this.uniforms["map3"].value, this.uniforms["map3Normal"].value);
        this.needsUpdate = true;
    }

    private setRepeat(map: THREE.Texture, normal: THREE.Texture): void {
        let v4: THREE.Vector4 = this.uniforms["offsetRepeat"].value;
        if (v4.y != 1 || v4.z != 1) {
            if (map) map.wrapS = map.wrapT = THREE.RepeatWrapping;
            if (normal) normal.wrapS = normal.wrapT = THREE.RepeatWrapping;
        }
    }

    public setMap1(map: THREE.Texture, normal: THREE.Texture, heightRange: number) {
        this.setRepeat(map, normal);
        this.uniforms["map1"].value = map;
        this.uniforms["map1Normal"].value = normal;
        this.uniforms["map1HeightRange"].value = heightRange;
        this.needsUpdate = true;
    }

    public setMap2(map: THREE.Texture, normal: THREE.Texture, heightRange: number) {
        this.setRepeat(map, normal);
        this.uniforms["map2"].value = map;
        this.uniforms["map2Normal"].value = normal;
        this.uniforms["map2HeightRange"].value = heightRange;
        this.needsUpdate = true;
    }

    public setMap3(map: THREE.Texture, normal: THREE.Texture, heightRange: number) {
        this.setRepeat(map, normal);
        this.uniforms["map3"].value = map;
        this.uniforms["map3Normal"].value = normal;
        this.uniforms["map3HeightRange"].value = heightRange;
        this.needsUpdate = true;
    }
}

and usage:

let loader = new THREE.TextureLoader();
let terrainMat = new TerrainMaterial();
terrainMat.dithering = Config.DITHERING;
terrainMat.setOffsetRepeat(0, 0, 80, 80);
let map1 = loader.load("images/maps/ground/shatter.jpg");
let map1Normal = loader.load("images/maps/ground/shatter_normal.png");
map1.anisotropy = map1Normal.anisotropy = anisotropy;
let map2 = loader.load("images/maps/ground/earth.jpg");
let map2Normal = loader.load("images/maps/ground/earth_normal.png");
map2.anisotropy = map2Normal.anisotropy = anisotropy;
let map3 = loader.load("images/maps/ground/moss.jpg");
let map3Normal = loader.load("images/maps/ground/moss_normal.png");
map3.anisotropy = map3Normal.anisotropy = anisotropy;
let hStep = GroundGeometry.MAX_HEIGHT / 4;
terrainMat.setMap1(map1, map1Normal, hStep);
terrainMat.setMap2(map2, map2Normal, hStep * 2);
terrainMat.setMap3(map3, map3Normal, hStep * 4);

//note: replace new THREE.PlaneGeometry as your terrain geometry so the mateiral can detect height change. otherise the plane will be filled full with the same 1 map.
let p = new THREE.Mesh(new THREE.PlaneGeometry(900, 900, 257, 257), terrainMat);
p.geometry.rotateX(-NumberConsts.PI_2);
scene.add(p);

result:

[Thundros]

how to do this in r117? Demo???

[WestLangley]

@Thundros You can get help at the three.js forum.