Class Advection

components/liquid-ether.tsx:632–687

    }

    class Advection extends ShaderPass {
      line!: THREE.LineSegments;
      constructor(simProps: any) {
        super({
          material: {
            vertexShader: face_vert,
            fragmentShader: advection_frag,
            uniforms: {
              boundarySpace: { value: simProps.cellScale },
              px: { value: simProps.cellScale },
              fboSize: { value: simProps.fboSize },
              velocity: { value: simProps.src.texture },
              dt: { value: simProps.dt },
              isBFECC: { value: true },
            },
          },
          output: simProps.dst,
        });
        this.uniforms = this.props.material.uniforms;
        this.init();
      }
      init() {
        super.init();
        this.createBoundary();
      }
      createBoundary() {
        const boundaryG = new THREE.BufferGeometry();
        const vertices_boundary = new Float32Array([
          -1, -1, 0, -1, 1, 0, -1, 1, 0, 1, 1, 0, 1, 1, 0, 1, -1, 0, 1, -1, 0,
          -1, -1, 0,
        ]);
        boundaryG.setAttribute(
          "position",
          new THREE.BufferAttribute(vertices_boundary, 3)
        );
        const boundaryM = new THREE.RawShaderMaterial({
          vertexShader: line_vert,
          fragmentShader: advection_frag,
          uniforms: this.uniforms!,
        });
        this.line = new THREE.LineSegments(boundaryG, boundaryM);
        this.scene!.add(this.line);
      }
      update(...args: any[]) {
        const { dt, isBounce, BFECC } = (args[0] || {}) as {
          dt?: number;
          isBounce?: boolean;
          BFECC?: boolean;
        };
        if (!this.uniforms) return;
        if (typeof dt === "number") this.uniforms.dt.value = dt;
        if (typeof isBounce === "boolean") this.line.visible = isBounce;
        if (typeof BFECC === "boolean") this.uniforms.isBFECC.value = BFECC;
        super.update();
      }
    }

    class ExternalForce extends ShaderPass {