Fix incorrect sun disk smoothing

Author: sergcpp

internal/AtmosphereRef.cpp

@@ -843,8 +843,9 @@ Ray::Ref::fvec4 Ray::Ref::IntegrateScattering(const atmosphere_params_t &params,
     //
     if (light_angle > 0.0f && planet_intersection.get<0>() < 0.0f && light_brightness > 0.0f) {
         const float cos_theta = cosf(light_angle);
+        const float smooth_blend_val = fminf(SKY_SUN_BLEND_VAL, 1.0f - cos_theta);
         fvec4 sun_disk =
-            total_transmittance * smoothstep(cos_theta - SKY_SUN_BLEND_VAL, cos_theta + SKY_SUN_BLEND_VAL, costh);
+            total_transmittance * smoothstep(cos_theta - smooth_blend_val, cos_theta + smooth_blend_val, costh);
         // 'de-multiply' by disk area (to get original brightness)
         const float radius = tanf(light_angle);
         sun_disk /= (PI * radius * radius);

internal/SceneCommon.cpp

@@ -179,7 +179,7 @@ void Ray::SceneCommon::SetCamera_nolock(const CameraHandle i, const camera_desc_
 #ifdef DUMP_SKY_ENV
 extern "C" {
 int SaveEXR(const float *data, int width, int height, int components, const int save_as_fp16,
-            std::string_view outfilename, const char **err);
+            const char *outfilename, const char **err);
 }
 #endif
 

internal/SceneGPU.h

@@ -1635,7 +1635,7 @@ inline void Ray::NS::Scene::Rebuild_SWRT_TLAS_nolock() {
 #ifdef DUMP_SKY_ENV
 extern "C" {
 int SaveEXR(const float *data, int width, int height, int components, const int save_as_fp16,
-            std::string_view outfilename, const char **err);
+            const char *outfilename, const char **err);
 }
 #endif
 

internal/shaders/output/bake_sky.comp.cso.inl

@@ -625,7 +625,8 @@ vec3 IntegrateScattering(vec3 ray_start, const vec3 ray_dir, float ray_length, u
     //
     if (g_params.light_dir.w > 0.0 && planet_intersection.x < 0.0 && light_brightness > 0.0) {
         const float cos_theta = g_params.light_col.w;
-        const vec3 sun_disk = total_transmittance * smoothstep(cos_theta - SKY_SUN_BLEND_VAL, cos_theta + SKY_SUN_BLEND_VAL, costh);
+        const float smooth_blend_val = min(SKY_SUN_BLEND_VAL, 1.0 - cos_theta);
+        const vec3 sun_disk = total_transmittance * smoothstep(cos_theta - smooth_blend_val, cos_theta + smooth_blend_val, costh);
         total_radiance += sun_disk * g_params.light_col.xyz;
     }