forestia/bevy
2
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

Add second Lambertian lobe-based diffuse transmission to PBR shader

Browse Source
This commit is contained in:
Marco Buono 2023-04-15 23:57:24 -03:00
parent cfd58599a0
commit e2b816bc7c
1 changed files with 94 additions and 5 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

99
crates/bevy_pbr/src/render/pbr_functions.wgsl
View File

@ -187,8 +187,14 @@ fn pbr(
let reflectance = in.material.reflectance;
let F0 = 0.16 * reflectance * reflectance * (1.0 - metallic) + output_color.rgb * metallic;
// Diffuse strength inversely related to metallicity and transmission
let diffuse_color = output_color.rgb * (1.0 - metallic) * (1.0 - transmission);
// Diffuse strength is inversely related to metallicity, specular and diffuse transmission
let diffuse_color = output_color.rgb * (1.0 - metallic) * (1.0 - transmission) * (1.0 - diffuse_transmission);
// Diffuse transmissive strength is inversely related to metallicity and specular transmission, but directly related to diffuse transmission
let diffuse_transmissive_color = output_color.rgb * (1.0 - metallic) * (1.0 - transmission) * diffuse_transmission;
// Calculate the world position of the second Lambertian lobe used for diffuse transmission, by subtracting material thickness
let diffuse_transmissive_lobe_world_position = in.world_position - vec4<f32>(in.world_normal, 0.0) * thickness;
let R = reflect(-in.V, in.N);
@ -196,6 +202,9 @@ fn pbr(
var direct_light: vec3<f32> = vec3<f32>(0.0);
// Transmitted Light (Specular and Diffuse)
var transmitted_light: vec3<f32> = vec3<f32>(0.0);
let view_z = dot(vec4<f32>(
view.inverse_view[0].z,
view.inverse_view[1].z,
@ -215,6 +224,24 @@ fn pbr(
}
let light_contrib = point_light(in.world_position.xyz, light_id, roughness, NdotV, in.N, in.V, R, F0, f_ab, diffuse_color);
direct_light += light_contrib * shadow;
if diffuse_transmission > 0.0 {
// NOTE: We use the diffuse transmissive color, the second Lambertian lobe's calculated
// world position, inverted normal and view vectors, and the following simplified
// values for a fully diffuse transmitted light contribution approximation:
//
// roughness = 1.0;
// NdotV = 1.0;
// R = vec3<f32>(0.0) // doesn't really matter
// f_ab = vec2<f32>(0.1)
// F0 = vec3<f32>(0.0)
if ((in.flags & MESH_FLAGS_SHADOW_RECEIVER_BIT) != 0u
&& (point_lights.data[light_id].flags & POINT_LIGHT_FLAGS_SHADOWS_ENABLED_BIT) != 0u) {
shadow = fetch_point_shadow(light_id, diffuse_transmissive_lobe_world_position, -in.world_normal);
}
let light_contrib = point_light(diffuse_transmissive_lobe_world_position.xyz, light_id, 1.0, 1.0, -in.N, -in.V, vec3<f32>(0.0), vec3<f32>(0.0), vec2<f32>(0.1), diffuse_transmissive_color);
transmitted_light += light_contrib * shadow;
}
}
// Spot lights (direct)
@ -227,6 +254,24 @@ fn pbr(
}
let light_contrib = spot_light(in.world_position.xyz, light_id, roughness, NdotV, in.N, in.V, R, F0, f_ab, diffuse_color);
direct_light += light_contrib * shadow;
if diffuse_transmission > 0.0 {
// NOTE: We use the diffuse transmissive color, the second Lambertian lobe's calculated
// world position, inverted normal and view vectors, and the following simplified
// values for a fully diffuse transmitted light contribution approximation:
//
// roughness = 1.0;
// NdotV = 1.0;
// R = vec3<f32>(0.0) // doesn't really matter
// f_ab = vec2<f32>(0.1)
// F0 = vec3<f32>(0.0)
if ((in.flags & MESH_FLAGS_SHADOW_RECEIVER_BIT) != 0u
&& (point_lights.data[light_id].flags & POINT_LIGHT_FLAGS_SHADOWS_ENABLED_BIT) != 0u) {
shadow = fetch_spot_shadow(light_id, diffuse_transmissive_lobe_world_position, -in.world_normal);
}
let light_contrib = spot_light(diffuse_transmissive_lobe_world_position.xyz, light_id, 1.0, 1.0, -in.N, -in.V, vec3<f32>(0.0), vec3<f32>(0.0), vec2<f32>(0.1), diffuse_transmissive_color);
transmitted_light += light_contrib * shadow;
}
}
// Directional lights (direct)
@ -242,23 +287,67 @@ fn pbr(
light_contrib = cascade_debug_visualization(light_contrib, i, view_z);
#endif
direct_light += light_contrib * shadow;
if diffuse_transmission > 0.0 {
// NOTE: We use the diffuse transmissive color, the second Lambertian lobe's calculated
// world position, inverted normal and view vectors, and the following simplified
// values for a fully diffuse transmitted light contribution approximation:
//
// roughness = 1.0;
// NdotV = 1.0;
// R = vec3<f32>(0.0) // doesn't really matter
// f_ab = vec2<f32>(0.1)
// F0 = vec3<f32>(0.0)
if ((in.flags & MESH_FLAGS_SHADOW_RECEIVER_BIT) != 0u
&& (lights.directional_lights[i].flags & DIRECTIONAL_LIGHT_FLAGS_SHADOWS_ENABLED_BIT) != 0u) {
shadow = fetch_directional_shadow(i, diffuse_transmissive_lobe_world_position, -in.world_normal, view_z);
}
let light_contrib = directional_light(i, 1.0, 1.0, -in.N, -in.V, vec3<f32>(0.0), vec3<f32>(0.0), vec2<f32>(0.1), diffuse_transmissive_color);
transmitted_light += light_contrib * shadow;
}
}
// Ambient light (indirect)
var indirect_light = ambient_light(in.world_position, in.N, in.V, NdotV, diffuse_color, F0, perceptual_roughness, occlusion);
if diffuse_transmission > 0.0 {
// NOTE: We use the diffuse transmissive color, the second Lambertian lobe's calculated
// world position, inverted normal and view vectors, and the following simplified
// values for a fully diffuse transmitted light contribution approximation:
//
// perceptual_roughness = 1.0;
// NdotV = 1.0;
// F0 = vec3<f32>(0.0)
// occlusion = 1.0
transmitted_light += ambient_light(diffuse_transmissive_lobe_world_position, -in.N, -in.V, 1.0, diffuse_transmissive_color, vec3<f32>(0.0), 1.0, 1.0);
}
// Environment map light (indirect)
#ifdef ENVIRONMENT_MAP
let environment_light = environment_map_light(perceptual_roughness, roughness, diffuse_color, NdotV, f_ab, in.N, R, F0);
indirect_light += (environment_light.diffuse * occlusion) + environment_light.specular;
if diffuse_transmission > 0.0 {
// NOTE: We use the diffuse transmissive color, the second Lambertian lobe's calculated
// world position, inverted normal and view vectors, and the following simplified
// values for a fully diffuse transmitted light contribution approximation:
//
// perceptual_roughness = 1.0;
// roughness = 1.0;
// NdotV = 1.0;
// f_ab = vec2<f32>(0.1)
// R = vec3<f32>(0.0) // doesn't really matter
// F0 = vec3<f32>(0.0)
// occlusion = 1.0
let environment_light = environment_map_light(1.0, 1.0, diffuse_transmissive_color, 1.0, vec2<f32>(0.1), -in.N, vec3<f32>(0.0), vec3<f32>(0.0));
transmitted_light += environment_light.diffuse;
}
#endif
let emissive_light = emissive.rgb * output_color.a;
// Transmitted Light
var transmitted_light: vec3<f32> = vec3<f32>(0.0);
if transmission > 0.0 {
transmitted_light = transmissive_light(in.world_position, in.frag_coord.xyz, in.N, in.V, ior, thickness, perceptual_roughness, transmissive_color).rgb;
transmitted_light += transmissive_light(in.world_position, in.frag_coord.xyz, in.N, in.V, ior, thickness, perceptual_roughness, transmissive_color).rgb;
}
// Total light