typegpu/core/function/tgpuVertexFn.js

A thin layer between JS and WebGPU/WGSL that improves development experience and allows for faster iteration.

import { getName, setName } from "../../shared/meta.js";
import { $getNameForward, $internal, $resolve } from "../../shared/symbols.js";
import { shaderStageSlot } from "../slot/internalSlots.js";
import { createFnCore } from "./fnCore.js";
import { createIoSchema, separateAllAsPositional } from "./ioSchema.js";
import { stripTemplate } from "./templateUtils.js";
/**
 * Creates a shell of a typed entry function for the vertex shader stage. Any function
 * that implements this shell can run for each vertex, allowing the inner code to process
 * attributes and determine the final position of the vertex.
 *
 * @param options.in
 *   Vertex attributes and builtins to be made available to functions that implement this shell.
 * @param options.out
 *   A record containing the final position of the vertex, and any information
 *   passed onto the fragment shader stage.
 */
export function vertexFn(options) {
    if (Object.keys(options.out).length === 0) {
        throw new Error(`A vertexFn output cannot be empty since it must include the 'position' builtin.`);
    }
    const shell = {
        in: options.in,
        out: options.out,
        argTypes: options.in && Object.keys(options.in).length !== 0 ? [createIoSchema(options.in)] : [],
        entryPoint: 'vertex',
    };
    const call = (arg, ...values) => createVertexFn(shell, stripTemplate(arg, ...values));
    return Object.assign(call, shell);
}
export function isTgpuVertexFn(value) {
    return value?.shell?.entryPoint === 'vertex';
}
// --------------
// Implementation
// --------------
function createVertexFn(shell, implementation) {
    const core = createFnCore(implementation, 'vertex');
    const entryInput = separateAllAsPositional(shell.in ?? {});
    const result = {
        shell,
        $uses(newExternals) {
            core.setExternals('userProvided', newExternals);
            return this;
        },
        [$internal]: true,
        [$getNameForward]: core,
        $name(newLabel) {
            setName(this, newLabel);
            return this;
        },
        [$resolve](ctx) {
            const outputWithLocation = createIoSchema(shell.out, ctx.varyingLocations).$name(`${getName(this) ?? ''}_Output`);
            if (typeof implementation === 'string') {
                core.setExternals('out', { Out: outputWithLocation });
            }
            return ctx.withSlots([[shaderStageSlot, 'vertex']], () => core.resolve(ctx, [], outputWithLocation, entryInput));
        },
        toString() {
            return `vertexFn:${getName(core) ?? '<unnamed>'}`;
        },
    };
    return result;
}