(function (global, factory) {
  if (typeof define === "function" && define.amd) {
    define(["exports", "three"], factory);
  } else if (typeof exports !== "undefined") {
    factory(exports, require("three"));
  } else {
    var mod = {
      exports: {}
    };
    factory(mod.exports, global.three);
    global.GodRaysShader = mod.exports;
  }
})(typeof globalThis !== "undefined" ? globalThis : typeof self !== "undefined" ? self : this, function (_exports, _three) {
  "use strict";

  Object.defineProperty(_exports, "__esModule", {
    value: true
  });
  _exports.GodRaysGenerateShader = _exports.GodRaysFakeSunShader = _exports.GodRaysDepthMaskShader = _exports.GodRaysCombineShader = void 0;

  /**
   * God-rays (crepuscular rays)
   *
   * Similar implementation to the one used by Crytek for CryEngine 2 [Sousa2008].
   * Blurs a mask generated from the depth map along radial lines emanating from the light
   * source. The blur repeatedly applies a blur filter of increasing support but constant
   * sample count to produce a blur filter with large support.
   *
   * My implementation performs 3 passes, similar to the implementation from Sousa. I found
   * just 6 samples per pass produced acceptible results. The blur is applied three times,
   * with decreasing filter support. The result is equivalent to a single pass with
   * 6*6*6 = 216 samples.
   *
   * References:
   *
   * Sousa2008 - Crysis Next Gen Effects, GDC2008, http://www.crytek.com/sites/default/files/GDC08_SousaT_CrysisEffects.ppt
   */
  var GodRaysDepthMaskShader = {
    uniforms: {
      tInput: {
        value: null
      }
    },
    vertexShader:
    /* glsl */
    "\n\n\t\tvarying vec2 vUv;\n\n\t\tvoid main() {\n\n\t\t vUv = uv;\n\t\t gl_Position = projectionMatrix * modelViewMatrix * vec4( position, 1.0 );\n\n\t }",
    fragmentShader:
    /* glsl */
    "\n\n\t\tvarying vec2 vUv;\n\n\t\tuniform sampler2D tInput;\n\n\t\tvoid main() {\n\n\t\t\tgl_FragColor = vec4( 1.0 ) - texture2D( tInput, vUv );\n\n\t\t}"
  };
  /**
   * The god-ray generation shader.
   *
   * First pass:
   *
   * The depth map is blurred along radial lines towards the "sun". The
   * output is written to a temporary render target (I used a 1/4 sized
   * target).
   *
   * Pass two & three:
   *
   * The results of the previous pass are re-blurred, each time with a
   * decreased distance between samples.
   */

  _exports.GodRaysDepthMaskShader = GodRaysDepthMaskShader;
  var GodRaysGenerateShader = {
    uniforms: {
      tInput: {
        value: null
      },
      fStepSize: {
        value: 1.0
      },
      vSunPositionScreenSpace: {
        value: new _three.Vector3()
      }
    },
    vertexShader:
    /* glsl */
    "\n\n\t\tvarying vec2 vUv;\n\n\t\tvoid main() {\n\n\t\t vUv = uv;\n\t\t gl_Position = projectionMatrix * modelViewMatrix * vec4( position, 1.0 );\n\n\t }",
    fragmentShader:
    /* glsl */
    "\n\n\t\t#define TAPS_PER_PASS 6.0\n\n\t\tvarying vec2 vUv;\n\n\t\tuniform sampler2D tInput;\n\n\t\tuniform vec3 vSunPositionScreenSpace;\n\t\tuniform float fStepSize; // filter step size\n\n\t\tvoid main() {\n\n\t\t// delta from current pixel to \"sun\" position\n\n\t\t\tvec2 delta = vSunPositionScreenSpace.xy - vUv;\n\t\t\tfloat dist = length( delta );\n\n\t\t// Step vector (uv space)\n\n\t\t\tvec2 stepv = fStepSize * delta / dist;\n\n\t\t// Number of iterations between pixel and sun\n\n\t\t\tfloat iters = dist/fStepSize;\n\n\t\t\tvec2 uv = vUv.xy;\n\t\t\tfloat col = 0.0;\n\n\t\t// This breaks ANGLE in Chrome 22\n\t\t//\t- see http://code.google.com/p/chromium/issues/detail?id=153105\n\n\t\t/*\n\t\t// Unrolling didnt do much on my hardware (ATI Mobility Radeon 3450),\n\t\t// so i've just left the loop\n\n\t\t\"for ( float i = 0.0; i < TAPS_PER_PASS; i += 1.0 ) {\",\n\n\t\t// Accumulate samples, making sure we dont walk past the light source.\n\n\t\t// The check for uv.y < 1 would not be necessary with \"border\" UV wrap\n\t\t// mode, with a black border color. I don't think this is currently\n\t\t// exposed by three.js. As a result there might be artifacts when the\n\t\t// sun is to the left, right or bottom of screen as these cases are\n\t\t// not specifically handled.\n\n\t\t\"\tcol += ( i <= iters && uv.y < 1.0 ? texture2D( tInput, uv ).r : 0.0 );\",\n\t\t\"\tuv += stepv;\",\n\n\t\t\"}\",\n\t\t*/\n\n\t\t// Unrolling loop manually makes it work in ANGLE\n\n\t\t\tfloat f = min( 1.0, max( vSunPositionScreenSpace.z / 1000.0, 0.0 ) ); // used to fade out godrays\n\n\t\t\tif ( 0.0 <= iters && uv.y < 1.0 ) col += texture2D( tInput, uv ).r * f;\n\t\t\tuv += stepv;\n\n\t\t\tif ( 1.0 <= iters && uv.y < 1.0 ) col += texture2D( tInput, uv ).r * f;\n\t\t\tuv += stepv;\n\n\t\t\tif ( 2.0 <= iters && uv.y < 1.0 ) col += texture2D( tInput, uv ).r * f;\n\t\t\tuv += stepv;\n\n\t\t\tif ( 3.0 <= iters && uv.y < 1.0 ) col += texture2D( tInput, uv ).r * f;\n\t\t\tuv += stepv;\n\n\t\t\tif ( 4.0 <= iters && uv.y < 1.0 ) col += texture2D( tInput, uv ).r * f;\n\t\t\tuv += stepv;\n\n\t\t\tif ( 5.0 <= iters && uv.y < 1.0 ) col += texture2D( tInput, uv ).r * f;\n\t\t\tuv += stepv;\n\n\t\t// Should technically be dividing by 'iters but 'TAPS_PER_PASS' smooths out\n\t\t// objectionable artifacts, in particular near the sun position. The side\n\t\t// effect is that the result is darker than it should be around the sun, as\n\t\t// TAPS_PER_PASS is greater than the number of samples actually accumulated.\n\t\t// When the result is inverted (in the shader 'godrays_combine this produces\n\t\t// a slight bright spot at the position of the sun, even when it is occluded.\n\n\t\t\tgl_FragColor = vec4( col/TAPS_PER_PASS );\n\t\t\tgl_FragColor.a = 1.0;\n\n\t\t}"
  };
  /**
   * Additively applies god rays from texture tGodRays to a background (tColors).
   * fGodRayIntensity attenuates the god rays.
   */

  _exports.GodRaysGenerateShader = GodRaysGenerateShader;
  var GodRaysCombineShader = {
    uniforms: {
      tColors: {
        value: null
      },
      tGodRays: {
        value: null
      },
      fGodRayIntensity: {
        value: 0.69
      }
    },
    vertexShader:
    /* glsl */
    "\n\n\t\tvarying vec2 vUv;\n\n\t\tvoid main() {\n\n\t\t\tvUv = uv;\n\t\t\tgl_Position = projectionMatrix * modelViewMatrix * vec4( position, 1.0 );\n\n\t\t}",
    fragmentShader:
    /* glsl */
    "\n\n\t\tvarying vec2 vUv;\n\n\t\tuniform sampler2D tColors;\n\t\tuniform sampler2D tGodRays;\n\n\t\tuniform float fGodRayIntensity;\n\n\t\tvoid main() {\n\n\t\t// Since THREE.MeshDepthMaterial renders foreground objects white and background\n\t\t// objects black, the god-rays will be white streaks. Therefore value is inverted\n\t\t// before being combined with tColors\n\n\t\t\tgl_FragColor = texture2D( tColors, vUv ) + fGodRayIntensity * vec4( 1.0 - texture2D( tGodRays, vUv ).r );\n\t\t\tgl_FragColor.a = 1.0;\n\n\t\t}"
  };
  /**
   * A dodgy sun/sky shader. Makes a bright spot at the sun location. Would be
   * cheaper/faster/simpler to implement this as a simple sun sprite.
   */

  _exports.GodRaysCombineShader = GodRaysCombineShader;
  var GodRaysFakeSunShader = {
    uniforms: {
      vSunPositionScreenSpace: {
        value: new _three.Vector3()
      },
      fAspect: {
        value: 1.0
      },
      sunColor: {
        value: new _three.Color(0xffee00)
      },
      bgColor: {
        value: new _three.Color(0x000000)
      }
    },
    vertexShader:
    /* glsl */
    "\n\n\t\tvarying vec2 vUv;\n\n\t\tvoid main() {\n\n\t\t\tvUv = uv;\n\t\t\tgl_Position = projectionMatrix * modelViewMatrix * vec4( position, 1.0 );\n\n\t\t}",
    fragmentShader:
    /* glsl */
    "\n\n\t\tvarying vec2 vUv;\n\n\t\tuniform vec3 vSunPositionScreenSpace;\n\t\tuniform float fAspect;\n\n\t\tuniform vec3 sunColor;\n\t\tuniform vec3 bgColor;\n\n\t\tvoid main() {\n\n\t\t\tvec2 diff = vUv - vSunPositionScreenSpace.xy;\n\n\t\t// Correct for aspect ratio\n\n\t\t\tdiff.x *= fAspect;\n\n\t\t\tfloat prop = clamp( length( diff ) / 0.5, 0.0, 1.0 );\n\t\t\tprop = 0.35 * pow( 1.0 - prop, 3.0 );\n\n\t\t\tgl_FragColor.xyz = ( vSunPositionScreenSpace.z > 0.0 ) ? mix( sunColor, bgColor, 1.0 - prop ) : bgColor;\n\t\t\tgl_FragColor.w = 1.0;\n\n\t\t}"
  };
  _exports.GodRaysFakeSunShader = GodRaysFakeSunShader;
});