@thi.ng/webgl/syntax.js

WebGL & GLSL abstraction layer

import { isArray } from "@thi.ng/checks/is-array";
import { GLSLVersion } from "@thi.ng/shader-ast-glsl/api";
const PREFIXES = {
  a: "a_",
  v: "v_",
  u: "u_",
  o: "o_"
};
const NO_PREFIXES = {
  a: "",
  v: "",
  u: "",
  o: ""
};
const SYNTAX = {
  /**
   * WebGL (GLSL ES 1.0)
   */
  [GLSLVersion.GLES_100]: {
    number: 100,
    attrib: (id, type, pre) => `attribute ${isArray(type) ? type[0] : type} ${pre.a}${id};`,
    varying: {
      vs: (id, type, pre) => __arrayDecl("varying", type, pre.v + id),
      fs: (id, type, pre) => __arrayDecl("varying", type, pre.v + id)
    },
    uniform: (id, u, pre) => __arrayDecl("uniform", u, pre.u + id),
    output: (id, type, pre) => isArray(type) ? `#define ${pre.o}${id} gl_FragData[${type[1]}]` : ""
  },
  /**
   * WebGL 2 (GLSL ES 3)
   */
  [GLSLVersion.GLES_300]: {
    number: 300,
    attrib: (id, type, pre) => isArray(type) ? `layout(location=${type[1]}) in ${type[0]} ${pre.a}${id};` : `in ${type} ${pre.a}${id};`,
    varying: {
      vs: (id, type, pre) => __arrayDecl("out", type, pre.v + id),
      fs: (id, type, pre) => __arrayDecl("in", type, pre.v + id)
    },
    uniform: (id, u, pre) => __arrayDecl("uniform", u, pre.u + id),
    output: (id, type, pre) => isArray(type) ? `layout(location=${type[1]}) out ${type[0]} ${pre.o}${id};` : `out ${type} ${pre.o}${id};`
  }
};
const __arrayDecl = (qualifier, decl, id) => {
  const type = isArray(decl) ? decl[0] : decl;
  return type.indexOf("[]") > 0 ? `${qualifier} ${type.replace("[]", "")} ${id}[${decl[1]}];` : `${qualifier} ${type} ${id};`;
};
const VERSION_CHECK = (ver, ok, fail = "") => {
  let cmp = ">=";
  if (!ok) {
    ok = fail;
    fail = null;
    cmp = "<";
  }
  return `#if __VERSION__ ${cmp} ${ver}
${ok}${fail ? `
#else
${fail}` : ""}
#endif`;
};
const ALIAS_TEXTURE = VERSION_CHECK(
  300,
  "",
  "#define texture texture2D"
);
const EXPORT_FRAGCOL = (body = "col", out = "o_fragColor") => VERSION_CHECK(300, `${out}=${body};`, `gl_FragColor=${body};`);
const GLSL_HEADER = `#ifdef GL_FRAGMENT_PRECISION_HIGH
precision highp int;
precision highp float;
#else
precision mediump int;
precision mediump float;
#endif
${VERSION_CHECK(300, "precision lowp sampler3D;")}
#ifndef PI
#define PI 3.141592653589793
#endif
#ifndef TAU
#define TAU 6.283185307179586
#endif
#ifndef HALF_PI
#define HALF_PI 1.570796326794896
#endif
`;
export {
  ALIAS_TEXTURE,
  EXPORT_FRAGCOL,
  GLSL_HEADER,
  NO_PREFIXES,
  PREFIXES,
  SYNTAX,
  VERSION_CHECK
};