Some tweaks to vector component handling

[libs/gl.git] / builtin_data / _sky.glsl

diff --git a/builtin_data/_sky.glsl b/builtin_data/_sky.glsl
index 3493b5a48e92711bcf9a0ceaa7d53871bb753b35..1dbda5793f2d838018b1f8558ede2da7f03437da 100644 (file)
--- a/builtin_data/_sky.glsl
+++ b/builtin_data/_sky.glsl
@@ -88,13 +88,8 @@ float ray_sphere_intersect(vec3 ray_start, vec3 ray_dir, vec3 sphere_center, flo
        if(d_sq>r_sq)
                return -1.0;
 
-       float offset = sqrt(r_sq-d_sq);
-       if(offset<t)
-               return t-offset;
-       else if(offset>-t)
-               return t+offset;
-       else
-               return -1.0;
+       float offset = sqrt(r_sq-d_sq)*sign(sphere_radius);
+       return t-offset;
 }
 
 #pragma MSP stage(fragment)
@@ -110,7 +105,7 @@ OpticalPathInfo raymarch_path(float start_height, vec3 look_dir)
        vec3 path_extinction = vec3(0.0);
 
        float ground_t = ray_sphere_intersect(pos, look_dir, planet_center, planet_radius);
-       float space_t = ray_sphere_intersect(pos, look_dir, planet_center, planet_radius+atmosphere_thickness);
+       float space_t = ray_sphere_intersect(pos, look_dir, planet_center, -(planet_radius+atmosphere_thickness));
        float ray_length = (ground_t>0.0 ? ground_t : space_t);
        float step_size = ray_length/n_steps;
 
@@ -123,11 +118,15 @@ OpticalPathInfo raymarch_path(float start_height, vec3 look_dir)
 
                AtmosphericEvents ev = calculate_events(height);
                vec3 transmittance = exp(-path_extinction);
-               vec3 in_transmittance = texture(transmittance_lookup, vec2(sqrt(height/atmosphere_thickness), light_z)).rgb;
-               vec3 in_luminance = (ev.rayleigh_scatter*p_rayleigh+ev.mie_scatter*p_mie)*step_size;
-               if(i==n_steps && ground_t>0.0)
-                       in_luminance += ground_albedo*light_z/PI;
-               path_luminance += transmittance*in_transmittance*in_luminance;
+               float in_ground_t = ray_sphere_intersect(pos, light_dir, planet_center, planet_radius);
+               if(in_ground_t<0.0)
+               {
+                       vec3 in_transmittance = texture(transmittance_lookup, vec2(sqrt(height/atmosphere_thickness), light_z)).rgb;
+                       vec3 in_luminance = (ev.rayleigh_scatter*p_rayleigh+ev.mie_scatter*p_mie)*step_size;
+                       if(i==n_steps && ground_t>0.0 && light_z>0.0)
+                               in_luminance += ground_albedo*light_z/PI;
+                       path_luminance += transmittance*in_transmittance*in_luminance;
+               }
 
                path_extinction += total_extinction(ev)*step_size;
                pos += look_dir*step_size;