add bloom;some treaks

Editor/assets/shaders/PreethamSky.glsl

@@ -7,6 +7,8 @@ layout(binding = 0, rgba32f) restrict writeonly uniform imageCube o_CubeMap;
 
 uniform vec3 u_TurbidityAzimuthInclination;
 
+#define PI 3.14159265359
+
 vec3 GetCubeMapTexCoord()
 {
     vec2 st = gl_GlobalInvocationID.xy / vec2(imageSize(o_CubeMap));
@@ -22,11 +24,10 @@ vec3 GetCubeMapTexCoord()
     return normalize(ret);
 }
 
-#define PI 3.14159265359
 
 float saturatedDot( in vec3 a, in vec3 b )
 {
-    return max( dot( a, b ), 0.0 );
+    return clamp(dot(a, b), 0.0, 1.0);
 }
 
 vec3 YxyToXYZ( in vec3 Yxy )
@@ -96,6 +97,7 @@ vec3 calculateZenithLuminanceYxy( in float t, in float thetaS )
 
 vec3 calculatePerezLuminanceYxy( in float theta, in float gamma, in vec3 A, in vec3 B, in vec3 C, in vec3 D, in vec3 E )
 {
+    float cosTheta = max(cos(theta), 1e-6);
     return ( 1.0 + A * exp( B / cos( theta ) ) ) * ( 1.0 + C * exp( D * gamma ) + E * cos( gamma ) * cos( gamma ) );
 }
 
@@ -104,8 +106,8 @@ vec3 calculateSkyLuminanceRGB( in vec3 s, in vec3 e, in float t )
     vec3 A, B, C, D, E;
     calculatePerezDistribution( t, A, B, C, D, E );
 
-    float thetaS = acos( saturatedDot( s, vec3(0,1,0) ) );
-    float thetaE = acos( saturatedDot( e, vec3(0,1,0) ) );
+    float thetaS = acos(clamp(dot(s, vec3(0,1,0)), 0.0, 1.0));
+    float thetaE = acos(clamp(dot(e, vec3(0,1,0)), 0.0, 1.0));
     float gammaE = acos( saturatedDot( s, e )		   );
 
     vec3 Yz = calculateZenithLuminanceYxy( t, thetaS );
@@ -128,8 +130,30 @@ void main()
     float inclination   = u_TurbidityAzimuthInclination.z;
     vec3 sunDir     	= normalize( vec3( sin(inclination) * cos(azimuth), cos(inclination), sin(inclination) * sin(azimuth) ) );
     vec3 viewDir  		= cubeTC;
-    vec3 skyLuminance 	= calculateSkyLuminanceRGB( sunDir, viewDir, turbidity );
+
+    const float SUN_ANGULAR_RADIUS = 0.03465;
+    const float SUN_INTENSITY = 100.0;
+    vec3 skyLuminance;
+
+    if (viewDir.y < 0.0) {
+        skyLuminance = vec3(0.02);
+    } else {
+        skyLuminance = calculateSkyLuminanceRGB(sunDir, viewDir, turbidity);
+    }
+
+    float cosAngle = dot(viewDir, sunDir);
+    float angle = acos(cosAngle);
+    if (angle < SUN_ANGULAR_RADIUS) {
+        skyLuminance = vec3(SUN_INTENSITY);
+    } else {
+        float haloWidth = 0.1;
+        if (angle < SUN_ANGULAR_RADIUS + haloWidth) {
+            float t = (angle - SUN_ANGULAR_RADIUS) / haloWidth;
+            float haloFactor = 1.0 - smoothstep(0.0, 1.0, t);
+            skyLuminance += vec3(SUN_INTENSITY * 0.1 * haloFactor);
+        }
+    }
 
     vec4 color = vec4(skyLuminance * 0.05, 1.0);
     imageStore(o_CubeMap, ivec3(gl_GlobalInvocationID), color);
-}
+}