DistanceBasedFog.coffee

import * as THREE from "three"

class DistanceBasedFog
    constructor:(options)->
        @view=new THREE.Vector3
        @farnear=new THREE.Vector2
        @color=new THREE.Vector4
        return
    addShaderToMaterial:(material)->
        _this=@
        material.onBeforeCompile=(shader)->
            shader.uniforms.u_viewPos={value:_this.view}
            shader.uniforms.u_fogColor={value:_this.color}
            shader.uniforms.u_farnear={value:_this.farnear}

            shader.fragmentShader=[
                "uniform vec3 u_viewPos;"
                "uniform vec4 u_fogColor;"
                "uniform vec2 u_farnear;"
                shader.fragmentShader
            ].join("\n")

            shader.fragmentShader=shader.fragmentShader.replace(
                "gl_FragColor = vec4( outgoingLight, diffuseColor.a );"
                [
                    "float dist=length(u_viewPos-vViewPosition);"
                    "float fogAmount = smoothstep(u_farnear.x, u_farnear.y, dist);"
                    "gl_FragColor = vec4( outgoingLight, diffuseColor.a );"
                    "gl_FragColor = mix(gl_FragColor,u_fogColor,max(0.1,fogAmount));"
                ].join("\n")
            )

            shader.vertexShader=[
                "uniform float time;"
                "uniform mat4 u_worldView;"
                "attribute vec4 a_position;"
                shader.vertexShader
            ].join("\n")

            shader.vertexShader=shader.vertexShader.replace(
                "#include <fog_vertex>"
                [
                    "vec4 vViewPosition4 = modelViewMatrix * vec4(position, 1);"
                    "vViewPosition = vViewPosition4.xyz;"
                ].join("\n")
            )
            return
        return
export {DistanceBasedFog}