@pmndrs/uikit/dist/text/render/instanced-gylph-material.js

Build performant 3D user interfaces with Three.js and yoga.

import { MeshBasicMaterial } from 'three';
export class InstancedGlyphMaterial extends MeshBasicMaterial {
    constructor(font) {
        super({
            transparent: true,
            depthWrite: false,
            toneMapped: false,
        });
        this.onBeforeCompile = (parameters) => {
            parameters.uniforms.fontPage = { value: font.page };
            parameters.uniforms.pageSize = { value: [font.pageWidth, font.pageHeight] };
            parameters.uniforms.distanceRange = { value: font.distanceRange };
            parameters.vertexShader =
                `attribute vec4 instanceUVOffset;
        varying vec2 fontUv;
        attribute vec4 instanceRGBA;
        varying vec4 rgba;
        attribute mat4 instanceClipping;
        varying mat4 clipping;
        varying vec3 localPosition;
        ` + parameters.vertexShader;
            parameters.vertexShader = parameters.vertexShader.replace('#include <uv_vertex>', `#include <uv_vertex>
            fontUv = instanceUVOffset.xy + uv * instanceUVOffset.zw;
            rgba = instanceRGBA;
            clipping = instanceClipping;
            localPosition = (instanceMatrix * vec4(position, 1.0)).xyz;`);
            parameters.fragmentShader =
                `uniform sampler2D fontPage;
            uniform vec2 pageSize;
            uniform int distanceRange;
        varying vec2 fontUv;
        varying vec4 rgba;
        varying mat4 clipping;
        varying vec3 localPosition;
        float median(float r, float g, float b) {
            return max(min(r, g), min(max(r, g), b));
        }
        float getDistance() {
            vec3 msdf = texture(fontPage, fontUv).rgb;
            return median(msdf.r, msdf.g, msdf.b);
        }
        ` + parameters.fragmentShader;
            parameters.fragmentShader = parameters.fragmentShader.replace('#include <map_fragment>', ` #include <map_fragment>
          vec4 plane;
          float distanceToPlane, distanceGradient;
          float clipOpacity = 1.0;
          for(int i = 0; i < 4; i++) {
            plane = clipping[ i ];
            distanceToPlane = dot( localPosition, plane.xyz ) + plane.w;
            distanceGradient = fwidth( distanceToPlane ) / 2.0;
            clipOpacity *= smoothstep( - distanceGradient, distanceGradient, distanceToPlane );

            if ( clipOpacity == 0.0 ) discard;
          }
          // Distance to the edge of the glyph in texels.
          float dist = (getDistance() - 0.5) * float(distanceRange);

          // Calculate the antialiasing distance based on the number of texels per screen pixel.
          float aaDist = length(fwidth(fontUv * pageSize)) * 0.5;

          // Clamp the antialiasing distance to avoid excessive blurring.
          aaDist = clamp(aaDist, 0.0, float(distanceRange) * 0.5);

          float alpha = smoothstep(-aaDist, aaDist, dist);

          if (alpha <= 0.0) discard;

          // Apply gamma correction to improve text appearance.
          float gamma = 1.3;
          alpha = pow(alpha, 1.0 / gamma);

          diffuseColor.a *= clipOpacity * alpha;
          diffuseColor *= rgba;
            `);
        };
    }
}