HDR: Safer divisions

Shaders/HDR/atmos.glsl

@@ -240,7 +240,7 @@ float get_ray_end(vec3 ray_origin, vec3 ray_dir, float t_max)
     // Handle the camera being underground
     float earth_radius = min(ray_altitude, get_earth_radius());
     float atmos_dist  = ray_sphere_intersection(ray_origin, ray_dir, get_atmosphere_radius());
-    float ground_dist = ray_sphere_intersection(ray_origin, ray_dir, earth_radius);
+    float ground_dist = ray_sphere_intersection(ray_origin, ray_dir, earth_radius + 1e-3);
     float t_d;
     if (ray_altitude < get_atmosphere_radius()) {
         // We are inside the atmosphere

Shaders/HDR/atmos_aerial_perspective.frag

@@ -68,7 +68,7 @@ void main()
 
         ray_dir = ray_end - ray_origin;
         t_max = length(ray_dir);
-        ray_dir /= t_max;
+        ray_dir /= max(t_max, 1e-5);
     }
 
     vec4 transmittance;

Shaders/HDR/clustered.glsl

@@ -80,12 +80,13 @@ int getIndex(int counter)
     return int(texture(fg_ClusteredIndices, coords).r);
 }
 
-float get_square_falloff_attenuation(vec3 to_light, float inv_range)
+float get_square_falloff_attenuation(vec3 to_light, float range)
 {
+    float inv_range = 1.0 / max(range, 1e-5);
     float dd = dot(to_light, to_light);
     float factor = dd * inv_range * inv_range;
     float smooth_factor = max(1.0 - factor * factor, 0.0);
-    return (smooth_factor * smooth_factor) / max(dd, 0.0001);
+    return (smooth_factor * smooth_factor) / max(dd, 1e-5);
 }
 
 float get_spot_angle_attenuation(vec3 l, vec3 light_dir,
@@ -124,7 +125,7 @@ vec3 eval_scene_lights(vec3 base_color, float metallic, float roughness, vec3 f0
         vec3 L = normalize(to_light);
 
         float attenuation = get_square_falloff_attenuation(
-            to_light, 1.0 / light.range);
+            to_light, light.range);
         if (attenuation <= 0.0)
             continue;
 
@@ -144,7 +145,7 @@ vec3 eval_scene_lights(vec3 base_color, float metallic, float roughness, vec3 f0
         vec3 L = normalize(to_light);
 
         float attenuation = get_square_falloff_attenuation(
-            to_light, 1.0 / light.range);
+            to_light, light.range);
         attenuation *= get_spot_angle_attenuation(
             L, light.direction, light.cos_cutoff, light.exponent);
         if (attenuation <= 0.0)

Shaders/HDR/math.glsl

@@ -26,6 +26,10 @@ float safe_sqrt(float x) {
     return sqrt(max(x, 0.0));
 }
 
+float safe_asin(float x) {
+    return asin(clamp(x, -1.0, 1.0));
+}
+
 float safe_acos(float x) {
     return acos(clamp(x, -1.0, 1.0));
 }

Shaders/HDR/skydome.frag

@@ -24,6 +24,7 @@ const float SUN_SIN_HALF_ANGULAR_DIAMETER = 0.0047560042817014138; // sin(radian
 float M_PI();
 float sqr(float x);
 float saturate(float x);
+float safe_asin(float x);
 // atmos_spectral.glsl
 vec4 get_sun_spectral_irradiance();
 vec3 linear_srgb_from_spectral_samples(vec4 L);
@@ -51,7 +52,7 @@ void main()
     vec3 frag_ray_dir = normalize(ray_dir);
     float azimuth = atan(frag_ray_dir.y, frag_ray_dir.x) / M_PI() * 0.5 + 0.5;
     // Undo the non-linear transformation from the sky-view LUT
-    float l = asin(frag_ray_dir.z);
+    float l = safe_asin(frag_ray_dir.z);
     float elev = sqrt(abs(l) / (M_PI() * 0.5)) * sign(l) * 0.5 + 0.5;
 
     vec4 sky_radiance = texture(sky_view_tex, vec2(azimuth, elev));

Shaders/HDR/surface.glsl

@@ -87,7 +87,7 @@ vec3 surface_eval_analytical(
     float G = G1_Smith_GGX(NdotV, a2) * G1_Smith_GGX(NdotL, a2);
     float D = D_GGX(NdotH, a2);
 
-    vec3 f_specular = (F * a2) / (D * G);
+    vec3 f_specular = (F * a2) / max(D * G, 1e-5);
     vec3 f_diffuse = (vec3(1.0) - F) * c_diff * M_1_PI();
     vec3 bsdf = f_diffuse + f_specular;