(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.SSAOShader = mod.exports;
  }
})(typeof globalThis !== "undefined" ? globalThis : typeof self !== "undefined" ? self : this, function (_exports, _three) {
  "use strict";

  Object.defineProperty(_exports, "__esModule", {
    value: true
  });
  _exports.SSAOShader = _exports.SSAODepthShader = _exports.SSAOBlurShader = void 0;

  /**
   * References:
   * http://john-chapman-graphics.blogspot.com/2013/01/ssao-tutorial.html
   * https://learnopengl.com/Advanced-Lighting/SSAO
   * https://github.com/McNopper/OpenGL/blob/master/Example28/shader/ssao.frag.glsl
   */
  var SSAOShader = {
    defines: {
      'PERSPECTIVE_CAMERA': 1,
      'KERNEL_SIZE': 32
    },
    uniforms: {
      'tDiffuse': {
        value: null
      },
      'tNormal': {
        value: null
      },
      'tDepth': {
        value: null
      },
      'tNoise': {
        value: null
      },
      'kernel': {
        value: null
      },
      'cameraNear': {
        value: null
      },
      'cameraFar': {
        value: null
      },
      'resolution': {
        value: new _three.Vector2()
      },
      'cameraProjectionMatrix': {
        value: new _three.Matrix4()
      },
      'cameraInverseProjectionMatrix': {
        value: new _three.Matrix4()
      },
      'kernelRadius': {
        value: 8
      },
      'minDistance': {
        value: 0.005
      },
      'maxDistance': {
        value: 0.05
      }
    },
    vertexShader:
    /* glsl */
    "\n\n\t\tvarying vec2 vUv;\n\n\t\tvoid main() {\n\n\t\t\tvUv = uv;\n\n\t\t\tgl_Position = projectionMatrix * modelViewMatrix * vec4( position, 1.0 );\n\n\t\t}",
    fragmentShader:
    /* glsl */
    "\n\n\t\tuniform sampler2D tDiffuse;\n\t\tuniform sampler2D tNormal;\n\t\tuniform sampler2D tDepth;\n\t\tuniform sampler2D tNoise;\n\n\t\tuniform vec3 kernel[ KERNEL_SIZE ];\n\n\t\tuniform vec2 resolution;\n\n\t\tuniform float cameraNear;\n\t\tuniform float cameraFar;\n\t\tuniform mat4 cameraProjectionMatrix;\n\t\tuniform mat4 cameraInverseProjectionMatrix;\n\n\t\tuniform float kernelRadius;\n\t\tuniform float minDistance; // avoid artifacts caused by neighbour fragments with minimal depth difference\n\t\tuniform float maxDistance; // avoid the influence of fragments which are too far away\n\n\t\tvarying vec2 vUv;\n\n\t\t#include <packing>\n\n\t\tfloat getDepth( const in vec2 screenPosition ) {\n\n\t\t\treturn texture2D( tDepth, screenPosition ).x;\n\n\t\t}\n\n\t\tfloat getLinearDepth( const in vec2 screenPosition ) {\n\n\t\t\t#if PERSPECTIVE_CAMERA == 1\n\n\t\t\t\tfloat fragCoordZ = texture2D( tDepth, screenPosition ).x;\n\t\t\t\tfloat viewZ = perspectiveDepthToViewZ( fragCoordZ, cameraNear, cameraFar );\n\t\t\t\treturn viewZToOrthographicDepth( viewZ, cameraNear, cameraFar );\n\n\t\t\t#else\n\n\t\t\t\treturn texture2D( tDepth, screenPosition ).x;\n\n\t\t\t#endif\n\n\t\t}\n\n\t\tfloat getViewZ( const in float depth ) {\n\n\t\t\t#if PERSPECTIVE_CAMERA == 1\n\n\t\t\t\treturn perspectiveDepthToViewZ( depth, cameraNear, cameraFar );\n\n\t\t\t#else\n\n\t\t\t\treturn orthographicDepthToViewZ( depth, cameraNear, cameraFar );\n\n\t\t\t#endif\n\n\t\t}\n\n\t\tvec3 getViewPosition( const in vec2 screenPosition, const in float depth, const in float viewZ ) {\n\n\t\t\tfloat clipW = cameraProjectionMatrix[2][3] * viewZ + cameraProjectionMatrix[3][3];\n\n\t\t\tvec4 clipPosition = vec4( ( vec3( screenPosition, depth ) - 0.5 ) * 2.0, 1.0 );\n\n\t\t\tclipPosition *= clipW; // unprojection.\n\n\t\t\treturn ( cameraInverseProjectionMatrix * clipPosition ).xyz;\n\n\t\t}\n\n\t\tvec3 getViewNormal( const in vec2 screenPosition ) {\n\n\t\t\treturn unpackRGBToNormal( texture2D( tNormal, screenPosition ).xyz );\n\n\t\t}\n\n\t\tvoid main() {\n\n\t\t\tfloat depth = getDepth( vUv );\n\t\t\tfloat viewZ = getViewZ( depth );\n\n\t\t\tvec3 viewPosition = getViewPosition( vUv, depth, viewZ );\n\t\t\tvec3 viewNormal = getViewNormal( vUv );\n\n\t\t\tvec2 noiseScale = vec2( resolution.x / 4.0, resolution.y / 4.0 );\n\t\t\tvec3 random = texture2D( tNoise, vUv * noiseScale ).xyz;\n\n\t\t\t// compute matrix used to reorient a kernel vector\n\n\t\t\tvec3 tangent = normalize( random - viewNormal * dot( random, viewNormal ) );\n\t\t\tvec3 bitangent = cross( viewNormal, tangent );\n\t\t\tmat3 kernelMatrix = mat3( tangent, bitangent, viewNormal );\n\n\t\t float occlusion = 0.0;\n\n\t\t for ( int i = 0; i < KERNEL_SIZE; i ++ ) {\n\n\t\t\t\tvec3 sampleVector = kernelMatrix * kernel[ i ]; // reorient sample vector in view space\n\t\t\t\tvec3 samplePoint = viewPosition + ( sampleVector * kernelRadius ); // calculate sample point\n\n\t\t\t\tvec4 samplePointNDC = cameraProjectionMatrix * vec4( samplePoint, 1.0 ); // project point and calculate NDC\n\t\t\t\tsamplePointNDC /= samplePointNDC.w;\n\n\t\t\t\tvec2 samplePointUv = samplePointNDC.xy * 0.5 + 0.5; // compute uv coordinates\n\n\t\t\t\tfloat realDepth = getLinearDepth( samplePointUv ); // get linear depth from depth texture\n\t\t\t\tfloat sampleDepth = viewZToOrthographicDepth( samplePoint.z, cameraNear, cameraFar ); // compute linear depth of the sample view Z value\n\t\t\t\tfloat delta = sampleDepth - realDepth;\n\n\t\t\t\tif ( delta > minDistance && delta < maxDistance ) { // if fragment is before sample point, increase occlusion\n\n\t\t\t\t\tocclusion += 1.0;\n\n\t\t\t\t}\n\n\t\t\t}\n\n\t\t\tocclusion = clamp( occlusion / float( KERNEL_SIZE ), 0.0, 1.0 );\n\n\t\t\tgl_FragColor = vec4( vec3( 1.0 - occlusion ), 1.0 );\n\n\t\t}"
  };
  _exports.SSAOShader = SSAOShader;
  var SSAODepthShader = {
    defines: {
      'PERSPECTIVE_CAMERA': 1
    },
    uniforms: {
      'tDepth': {
        value: null
      },
      'cameraNear': {
        value: null
      },
      'cameraFar': {
        value: null
      }
    },
    vertexShader: "varying 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: "uniform sampler2D tDepth;\n\n\t\tuniform float cameraNear;\n\t\tuniform float cameraFar;\n\n\t\tvarying vec2 vUv;\n\n\t\t#include <packing>\n\n\t\tfloat getLinearDepth( const in vec2 screenPosition ) {\n\n\t\t\t#if PERSPECTIVE_CAMERA == 1\n\n\t\t\t\tfloat fragCoordZ = texture2D( tDepth, screenPosition ).x;\n\t\t\t\tfloat viewZ = perspectiveDepthToViewZ( fragCoordZ, cameraNear, cameraFar );\n\t\t\t\treturn viewZToOrthographicDepth( viewZ, cameraNear, cameraFar );\n\n\t\t\t#else\n\n\t\t\t\treturn texture2D( tDepth, screenPosition ).x;\n\n\t\t\t#endif\n\n\t\t}\n\n\t\tvoid main() {\n\n\t\t\tfloat depth = getLinearDepth( vUv );\n\t\t\tgl_FragColor = vec4( vec3( 1.0 - depth ), 1.0 );\n\n\t\t}"
  };
  _exports.SSAODepthShader = SSAODepthShader;
  var SSAOBlurShader = {
    uniforms: {
      'tDiffuse': {
        value: null
      },
      'resolution': {
        value: new _three.Vector2()
      }
    },
    vertexShader: "varying 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: "uniform sampler2D tDiffuse;\n\n\t\tuniform vec2 resolution;\n\n\t\tvarying vec2 vUv;\n\n\t\tvoid main() {\n\n\t\t\tvec2 texelSize = ( 1.0 / resolution );\n\t\t\tfloat result = 0.0;\n\n\t\t\tfor ( int i = - 2; i <= 2; i ++ ) {\n\n\t\t\t\tfor ( int j = - 2; j <= 2; j ++ ) {\n\n\t\t\t\t\tvec2 offset = ( vec2( float( i ), float( j ) ) ) * texelSize;\n\t\t\t\t\tresult += texture2D( tDiffuse, vUv + offset ).r;\n\n\t\t\t\t}\n\n\t\t\t}\n\n\t\t\tgl_FragColor = vec4( vec3( result / ( 5.0 * 5.0 ) ), 1.0 );\n\n\t\t}"
  };
  _exports.SSAOBlurShader = SSAOBlurShader;
});