@thi.ng/shader-ast-glsl/target.js

Customizable GLSL codegen for @thi.ng/shader-ast

import { isBoolean } from "@thi.ng/checks/is-boolean";
import { isNumber } from "@thi.ng/checks/is-number";
import { unsupported } from "@thi.ng/errors/unsupported";
import { F, V2, V4 } from "@thi.ng/shader-ast/api/types";
import { isMat, isVec } from "@thi.ng/shader-ast/ast/checks";
import { itemType } from "@thi.ng/shader-ast/ast/item";
import { sym } from "@thi.ng/shader-ast/ast/sym";
import { defTarget } from "@thi.ng/shader-ast/target";
import { GLSLVersion } from "./api.js";
const RE_SEMI = /[};]$/;
const targetGLSL = (opts) => {
  const _opts = {
    type: "fs",
    version: GLSLVersion.GLES_300,
    versionPragma: true,
    prelude: "",
    ...opts
  };
  const isVS = _opts.type === "vs";
  const ff = _opts.prec !== void 0 ? (x) => x === (x | 0) ? x + ".0" : x.toFixed(_opts.prec) : (x) => x === (x | 0) ? x + ".0" : String(x);
  const $type = (t) => t;
  const $list = (body, sep = ", ") => body.map(emit).join(sep);
  const $fn = (t) => `${t.id}(${$list(t.args)})`;
  const $decl = (sym2, arg = false) => {
    const { id, type, opts: opts2, init } = sym2;
    const res = [];
    if (opts2.type) {
      let type2;
      if (_opts.version < GLSLVersion.GLES_300) {
        if (isVS) {
          type2 = {
            in: "attribute",
            out: "varying",
            uni: "uniform"
          }[opts2.type];
        } else {
          type2 = {
            in: "varying",
            out: null,
            uni: "uniform"
          }[opts2.type];
          !type2 && unsupported(
            "GLSL 100 doesn't support fragment shader output variables"
          );
        }
      } else {
        opts2.loc != null && res.push(`layout(location=${opts2.loc}) `);
        opts2.smooth != null && res.push(opts2.smooth + " ");
        type2 = opts2.type === "uni" ? "uniform" : opts2.type;
      }
      res.push(type2 + " ");
    } else {
      opts2.const && res.push("const ");
      arg && opts2.q && res.push(opts2.q + " ");
    }
    opts2.prec && res.push(opts2.prec + " ");
    res.push($type(itemType(type)), " ", id);
    opts2.num && res.push(`[${opts2.num}]`);
    init && res.push(" = ", emit(init));
    return res.join("");
  };
  const emitIndex = (t) => `${emit(t.val)}[${emit(t.id)}]`;
  const emit = defTarget({
    arg: (t) => $decl(t, true),
    array_init: (t) => _opts.version >= GLSLVersion.GLES_300 ? `${t.type}(${$list(t.init)})` : unsupported(
      `array initializers not available in GLSL ${_opts.version}`
    ),
    assign: (t) => emit(t.l) + " = " + emit(t.r),
    ctrl: (t) => t.id,
    call: $fn,
    call_i: (t) => t.id === "texture" && _opts.version < GLSLVersion.GLES_300 ? `${t.id}${t.args[0].type.substring(7)}(${$list(
      t.args
    )})` : $fn(t),
    decl: (t) => $decl(t.id),
    fn: (t) => `${$type(t.type)} ${t.id}(${$list(t.args)}) ${emit(t.scope)}`,
    for: (t) => `for(${t.init ? emit(t.init) : ""}; ${emit(t.test)}; ${t.iter ? emit(t.iter) : ""}) ${emit(t.scope)}`,
    idx: emitIndex,
    idxm: emitIndex,
    if: (t) => {
      const res = `if (${emit(t.test)}) ` + emit(t.t);
      return t.f ? res + " else " + emit(t.f) : res;
    },
    lit: (t) => {
      const v = t.val;
      switch (t.type) {
        case "bool":
          return isBoolean(v) ? String(v) : `bool(${emit(v)})`;
        case "float":
          return isNumber(v) ? ff(v) : `float(${emit(v)})`;
        case "int":
          return isNumber(v) ? String(v) : `int(${emit(v)})`;
        case "uint":
          return isNumber(v) ? `${v}u` : `uint(${emit(v)})`;
        default: {
          if (isVec(t) || isMat(t)) {
            return `${t.type}(${$list(v)})`;
          }
          return unsupported(`unknown type: ${t.type}`);
        }
      }
    },
    op1: (t) => t.post ? `(${emit(t.val)}${t.op})` : `(${t.op}${emit(t.val)})`,
    op2: (t) => `(${emit(t.l)} ${t.op} ${emit(t.r)})`,
    ret: (t) => "return" + (t.val ? " " + emit(t.val) : ""),
    scope: (t) => {
      let res = t.body.map(emit).reduce(
        (acc, x) => (acc.push(RE_SEMI.test(x) ? x : x + ";"), acc),
        []
      ).join("\n");
      res += t.body.length && !RE_SEMI.test(res) ? ";" : "";
      if (!t.global) {
        return `{
${res}
}`;
      }
      if (_opts.prelude) {
        res = _opts.prelude + "\n" + res;
      }
      if (_opts.versionPragma) {
        res = `#version ${_opts.version}
` + res;
      }
      return res;
    },
    swizzle: (t) => `${emit(t.val)}.${t.id}`,
    sym: (t) => t.id,
    ternary: (t) => `(${emit(t.test)} ? ${emit(t.t)} : ${emit(t.f)})`,
    while: (t) => `while (${emit(t.test)}) ${emit(t.scope)}`
  });
  Object.assign(emit, {
    gl_FragColor: sym(V4, "gl_FragColor"),
    gl_FragCoord: sym(V4, "gl_FragCoord", { const: true }),
    gl_FragData: sym("vec4[]", "gl_FragData", { num: 1 }),
    gl_FrontFacing: sym("bool", "gl_FrontFacing", { const: true }),
    gl_PointCoord: sym(V2, "gl_PointCoord", { const: true }),
    gl_PointSize: sym(F, "gl_PointSize"),
    gl_Position: sym(V4, "gl_Position")
  });
  return emit;
};
export {
  targetGLSL
};