@woosh/meep-engine/src/engine/graphics/render/frame_graph/RenderGraphBuilder.js

Pure JavaScript game engine. Fully featured and production ready.

import { assert } from "../../../../core/assert.js";

export class RenderGraphBuilder {
    /**
     *
     * @type {RenderGraph}
     * @private
     */
    #graph = null;
    /**
     *
     * @type {RenderPassNode}
     * @private
     */
    #node = null;

    /**
     *
     * @param {RenderGraph} graph
     * @param {RenderPassNode} node
     */
    init(graph, node) {
        this.#graph = graph;
        this.#node = node;
    }

    /**
     * Create a new resource
     * @param {string} name
     * @param {ResourceDescriptor} descriptor
     * @returns {number} resource ID
     */
    create(name, descriptor) {
        const node = this.#graph.create_resource(name, descriptor);

        // remember resource
        this.#node.resource_creates.push(node);

        // creation implies writing as well
        this.#node.resource_writes.push(node);

        return node;
    }

    /**
     * Read an existing resource
     * @param {number} resource
     * @returns {number}
     */
    read(resource) {
        assert.isNonNegativeInteger(resource, 'resource');

        return this.#node.read(resource);
    }

    /**
     * Write a resource
     * @param {number} resource
     * @returns {number}
     */
    write(resource) {
        assert.isNonNegativeInteger(resource, 'resource');

        const graph = this.#graph;
        const node = this.#node;

        if (graph.getResourceEntry(resource).isImported()) {
            // comes from outside the graph, and we write to it. That's a side effect
            node.has_side_effects = true;
        }

        if (node.creates(resource)) {
            return node.write(resource);
        } else {
            // writing to a resource produces a renamed handle
            node.read(resource);

            return node.write(graph.clone_resource(resource));
        }

    }

    /**
     * Will force the node to be executed
     */
    make_side_effect() {
        this.#node.has_side_effects = true;
    }
}