WebGPU support for atmosphere add-on

packages/dev/addons/src/atmosphere/Shaders/ShadersInclude/atmosphereFunctions.fx

@@ -332,7 +332,7 @@ const float uniformPhase = RECIPROCAL_PI4;
 
 // Utilizes the transmittance LUT and multiple scattering LUT to compute the radiance and transmittance for a given ray.
 #define inline
-void integrateScatteredRadiance(
+vec3 integrateScatteredRadiance(
     bool isAerialPerspectiveLut,
     float lightIntensity,
     sampler2D transmittanceLut,
@@ -346,14 +346,13 @@ void integrateScatteredRadiance(
     float tMaxMax,
     float sampleCount,
     float distanceToSurface,
-    out vec3 radiance,
     out vec3 transmittance
     #if COMPUTE_MULTI_SCATTERING
         , out vec3 multiScattering
     #endif
     ) {
 
-    radiance = vec3(0.);
+    vec3 radiance = vec3(0.);
     transmittance = vec3(1.);
     #if COMPUTE_MULTI_SCATTERING
         multiScattering = vec3(0.);
@@ -366,7 +365,7 @@ void integrateScatteredRadiance(
     if (tBottom < 0.) {
         if (tTop < 0.) {
             // No intersection with the atmosphere or the planet, so early out.
-            return;
+            return radiance;
         } else {
             // Didn't intersect the planet, but did intersect the atmosphere.
             tMax = tTop;
@@ -456,6 +455,8 @@ void integrateScatteredRadiance(
 
     radiance *= lightIntensity;
 
+    return radiance;
+
 }
 
 #endif
@@ -632,10 +633,9 @@ vec4 renderMultiScattering(vec2 uv, sampler2D transmittanceLut) {
             float sinInclination;
             vec3 rayDirection = getSphereSample(azimuth, inclination, sinInclination);
 
-            vec3 radiance;
             vec3 transmittance;
             vec3 multiScattering;
-            integrateScatteredRadiance(
+            vec3 radiance = integrateScatteredRadiance(
                 false, // isAerialPerspectiveLut
                 1., // No light intensity; it will be applied in downstream LUTs (AerialPerspective, SkyView, and DiffuseSkyIrradiance).
                 transmittanceLut,
@@ -645,7 +645,6 @@ vec4 renderMultiScattering(vec2 uv, sampler2D transmittanceLut) {
                 100000000.,
                 MultiScatteringLutSampleCount,
                 -1., // No planet hit.
-                radiance,
                 transmittance,
                 multiScattering);
 
@@ -737,8 +736,7 @@ vec4 renderSkyView(vec2 uv, sampler2D transmittanceLut, sampler2D multiScatterin
     }
 
     vec3 transmittance;
-    vec3 radiance;
-    integrateScatteredRadiance(
+    vec3 radiance = integrateScatteredRadiance(
         false, // isAerialPerspectiveLut
         atmosphereExposure * lightIntensity,
         transmittanceLut,
@@ -750,7 +748,6 @@ vec4 renderSkyView(vec2 uv, sampler2D transmittanceLut, sampler2D multiScatterin
         100000000.,
         SkyViewLutSampleCount,
         -1., // No planet hit.
-        radiance,
         transmittance);
 
     float transparency = 1. - avg(transmittance);
@@ -804,8 +801,7 @@ vec4 renderCameraVolume(
 
     float sampleCount = min(SkyViewLutSampleCount, 2. * layer + 2.);
     vec3 transmittance;
-    vec3 radiance;
-    integrateScatteredRadiance(
+    vec3 radiance = integrateScatteredRadiance(
         true, // isAerialPerspectiveLut
         lightIntensity,
         transmittanceLut,
@@ -817,7 +813,6 @@ vec4 renderCameraVolume(
         tMaxMax,
         sampleCount,
         -1., // No planet hit.
-        radiance,
         transmittance);
 
     float transparency = 1. - avg(transmittance);

packages/dev/addons/src/atmosphere/Shaders/compositeAerialPerspective.fragment.fx

@@ -79,10 +79,9 @@ void main() {
             return;
         }
 
-        vec3 transmittance;
-        vec3 radiance;
         bool isAerialPerspectiveLut = clampedCameraRadius < atmosphereRadius;
-        integrateScatteredRadiance(
+        vec3 transmittance;
+        vec3 radiance = integrateScatteredRadiance(
             isAerialPerspectiveLut, // isAerialPerspectiveLut
             atmosphereExposure * lightIntensity,
             transmittanceLut,
@@ -94,7 +93,6 @@ void main() {
             100000000.,
             SkyViewLutSampleCount,
             distanceToSurface,
-            radiance,
             transmittance);
 
         float transparency = 1. - avg(transmittance);

packages/dev/addons/src/atmosphere/Shaders/compositeGlobeAtmosphere.fragment.fx

@@ -44,16 +44,15 @@ void main() {
 
         float cosAngleBetweenViewAndZenith;
         bool isRayIntersectingGround;
-        vec4 skyColor =
-            sampleSkyViewLut(
-                skyViewLut,
-                clampedCameraRadius,
-                cameraGeocentricNormal,
-                rayDirection,
-                directionToLight,
-                cosCameraHorizonAngleFromZenith,
-                cosAngleBetweenViewAndZenith,
-                isRayIntersectingGround);
+        vec4 skyColor = sampleSkyViewLut(
+            skyViewLut,
+            clampedCameraRadius,
+            cameraGeocentricNormal,
+            rayDirection,
+            directionToLight,
+            cosCameraHorizonAngleFromZenith,
+            cosAngleBetweenViewAndZenith,
+            isRayIntersectingGround);
 
         gl_FragColor = skyColor;
 
@@ -102,8 +101,7 @@ void main() {
         #endif
 
         vec3 transmittance;
-        vec3 radiance;
-        integrateScatteredRadiance(
+        vec3 radiance = integrateScatteredRadiance(
             false, // isAerialPerspectiveLut
             atmosphereExposure * lightIntensity,
             transmittanceLut,
@@ -115,7 +113,6 @@ void main() {
             100000000.,
             SkyViewLutSampleCount,
             distanceToSurface,
-            radiance,
             transmittance);
 
         float transparency = 1. - avg(transmittance);

packages/dev/addons/src/atmosphere/Shaders/compositeSky.fragment.fx

@@ -37,16 +37,15 @@ void main() {
 
         float cosAngleBetweenViewAndZenith;
         bool isRayIntersectingGround;
-        vec4 skyColor =
-            sampleSkyViewLut(
-                skyViewLut,
-                clampedCameraRadius,
-                cameraGeocentricNormal,
-                rayDirection,
-                directionToLight,
-                cosCameraHorizonAngleFromZenith,
-                cosAngleBetweenViewAndZenith,
-                isRayIntersectingGround);
+        vec4 skyColor = sampleSkyViewLut(
+            skyViewLut,
+            clampedCameraRadius,
+            cameraGeocentricNormal,
+            rayDirection,
+            directionToLight,
+            cosCameraHorizonAngleFromZenith,
+            cosAngleBetweenViewAndZenith,
+            isRayIntersectingGround);
 
         #ifndef APPLY_TRANSMITTANCE_BLENDING
             skyColor.a = 0.;
@@ -75,8 +74,7 @@ void main() {
         }
 
         vec3 transmittance;
-        vec3 radiance;
-        integrateScatteredRadiance(
+        vec3 radiance = integrateScatteredRadiance(
             false, // isAerialPerspectiveLut
             atmosphereExposure * lightIntensity,
             transmittanceLut,
@@ -88,7 +86,6 @@ void main() {
             100000000.,
             SkyViewLutSampleCount,
             -1., // No planet hit.
-            radiance,
             transmittance);
 
         #if APPLY_TRANSMITTANCE_BLENDING

packages/dev/addons/src/atmosphere/Shaders/diffuseSkyIrradiance.fragment.fx

@@ -15,9 +15,8 @@ uniform sampler2D multiScatteringLut;
 #include<atmosphereFunctions>
 
 vec3 integrateForIrradiance(vec3 directionToLight, vec3 rayDirection, vec3 rayOrigin) {
-    vec3 radiance;
     vec3 transmittance;
-    integrateScatteredRadiance(
+    vec3 radiance = integrateScatteredRadiance(
         false, // isAerialPerspectiveLut
         1.,
         transmittanceLut,
@@ -30,7 +29,6 @@ vec3 integrateForIrradiance(vec3 directionToLight, vec3 rayDirection, vec3 rayOr
         100000000.,
         DiffuseSkyIrradianceLutSampleCount,
         -1., // No planet hit.
-        radiance,
         transmittance);
     return radiance;
 }