Merge pull request #8798 from CesiumGS/fog-post-process

Fog post process sandcastle
CesiumGS · May 29, 2020 · fffeeea · fffeeea
2 parents 1b2a2cb + 129f4a6
commit fffeeea
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diff --git a/Apps/Sandcastle/gallery/Fog Post Process.html b/Apps/Sandcastle/gallery/Fog Post Process.html
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+<!DOCTYPE html>
+<html lang="en">
+  <head>
+    <meta charset="utf-8" />
+    <meta http-equiv="X-UA-Compatible" content="IE=edge" />
+    <meta
+      name="viewport"
+      content="width=device-width, initial-scale=1, maximum-scale=1, minimum-scale=1, user-scalable=no"
+    />
+    <meta name="description" content="Fog post process" />
+    <meta
+      name="cesium-sandcastle-labels"
+      content="Showcases, Post Processing"
+    />
+    <title>Cesium Demo</title>
+    <script type="text/javascript" src="../Sandcastle-header.js"></script>
+    <script type="text/javascript" src="../CesiumUnminified/Cesium.js"></script>
+  </head>
+  <body
+    class="sandcastle-loading"
+    data-sandcastle-bucket="bucket-requirejs.html"
+  >
+    <style>
+      @import url(../templates/bucket.css);
+    </style>
+    <div id="cesiumContainer" class="fullSize"></div>
+    <div id="loadingOverlay"><h1>Loading...</h1></div>
+    <div id="toolbar"></div>
+    <script id="cesium_sandcastle_script">
+      function startup(Cesium) {
+        "use strict";
+        //Sandcastle_Begin
+        var viewer = new Cesium.Viewer("cesiumContainer", {
+          shouldAnimate: true,
+        });
+
+        if (!viewer.scene.context.depthTexture) {
+          window.alert("This browser does not support the fog post process.");
+        }
+
+        var tileset = new Cesium.Cesium3DTileset({
+          url: Cesium.IonResource.fromAssetId(40866),
+        });
+
+        viewer.scene.primitives.add(tileset);
+
+        viewer.scene.camera.setView({
+          destination: new Cesium.Cartesian3(
+            1216356.033078094,
+            -4736402.278325668,
+            4081270.375520902
+          ),
+          orientation: new Cesium.HeadingPitchRoll(
+            0.08033365594766728,
+            -0.29519015695063455,
+            0.00027759141518046704
+          ),
+          endTransform: Cesium.Matrix4.IDENTITY,
+        });
+
+        var fragmentShaderSource =
+          "float getDistance(sampler2D depthTexture, vec2 texCoords) \n" +
+          "{ \n" +
+          "    float depth = czm_unpackDepth(texture2D(depthTexture, texCoords)); \n" +
+          "    if (depth == 0.0) { \n" +
+          "        return czm_infinity; \n" +
+          "    } \n" +
+          "    vec4 eyeCoordinate = czm_windowToEyeCoordinates(gl_FragCoord.xy, depth); \n" +
+          "    return -eyeCoordinate.z / eyeCoordinate.w; \n" +
+          "} \n" +
+          "float interpolateByDistance(vec4 nearFarScalar, float distance) \n" +
+          "{ \n" +
+          "    float startDistance = nearFarScalar.x; \n" +
+          "    float startValue = nearFarScalar.y; \n" +
+          "    float endDistance = nearFarScalar.z; \n" +
+          "    float endValue = nearFarScalar.w; \n" +
+          "    float t = clamp((distance - startDistance) / (endDistance - startDistance), 0.0, 1.0); \n" +
+          "    return mix(startValue, endValue, t); \n" +
+          "} \n" +
+          "vec4 alphaBlend(vec4 sourceColor, vec4 destinationColor) \n" +
+          "{ \n" +
+          "    return sourceColor * vec4(sourceColor.aaa, 1.0) + destinationColor * (1.0 - sourceColor.a); \n" +
+          "} \n" +
+          "uniform sampler2D colorTexture; \n" +
+          "uniform sampler2D depthTexture; \n" +
+          "uniform vec4 fogByDistance; \n" +
+          "uniform vec4 fogColor; \n" +
+          "varying vec2 v_textureCoordinates; \n" +
+          "void main(void) \n" +
+          "{ \n" +
+          "    float distance = getDistance(depthTexture, v_textureCoordinates); \n" +
+          "    vec4 sceneColor = texture2D(colorTexture, v_textureCoordinates); \n" +
+          "    float blendAmount = interpolateByDistance(fogByDistance, distance); \n" +
+          "    vec4 undergroundColor = vec4(fogColor.rgb, fogColor.a * blendAmount); \n" +
+          "    gl_FragColor = alphaBlend(undergroundColor, sceneColor); \n" +
+          "} \n";
+
+        var ellipsoid = viewer.scene.globe.ellipsoid;
+        var postProcessStage = viewer.scene.postProcessStages.add(
+          new Cesium.PostProcessStage({
+            fragmentShader: fragmentShaderSource,
+            uniforms: {
+              fogByDistance: new Cesium.Cartesian4(10, 0.0, 200, 1.0),
+              fogColor: Cesium.Color.BLACK,
+            },
+          })
+        ); //Sandcastle_End
+        Sandcastle.finishedLoading();
+      }
+      if (typeof Cesium !== "undefined") {
+        window.startupCalled = true;
+        startup(Cesium);
+      }
+    </script>
+  </body>
+</html>
diff --git a/Apps/Sandcastle/gallery/Fog Post Process.jpg b/Apps/Sandcastle/gallery/Fog Post Process.jpg