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Nishita sky: implement air and dust density

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This commit is contained in:
Moritz Brückner 2021-01-21 21:14:05 +01:00
parent 396e60574a
commit 288ead64dc
3 changed files with 25 additions and 11 deletions
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22
Shaders/std/sky.glsl
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@ -1,9 +1,12 @@
/* Various sky functions
* =====================
*
* Nishita model is based on https://github.com/wwwtyro/glsl-atmosphere (Unlicense License)
* Changes to the original implementation:
* - r and pSun parameters of nishita_atmosphere() are already normalized
* - Some original parameters of nishita_atmosphere() are replaced with pre-defined values
* Nishita model is based on https://github.com/wwwtyro/glsl-atmosphere(Unlicense License)
*
* Changes to the original implementation:
* - r and pSun parameters of nishita_atmosphere() are already normalized
* - Some original parameters of nishita_atmosphere() are replaced with pre-defined values
* - Implemented air and dust density node parameters (see Blender source)
*/
#ifndef _SKY_GLSL_
@ -47,8 +50,9 @@ vec2 nishita_rsi(const vec3 r0, const vec3 rd, const float sr) {
* r0: ray origin
* pSun: normalized sun direction
* rPlanet: planet radius
* density: (air density, dust density)
*/
vec3 nishita_atmosphere(const vec3 r, const vec3 r0, const vec3 pSun, const float rPlanet) {
vec3 nishita_atmosphere(const vec3 r, const vec3 r0, const vec3 pSun, const float rPlanet, const vec2 density) {
// Calculate the step size of the primary ray.
vec2 p = nishita_rsi(r0, r, nishita_atmo_radius);
if (p.x > p.y) return vec3(0,0,0);
@ -82,8 +86,8 @@ vec3 nishita_atmosphere(const vec3 r, const vec3 r0, const vec3 pSun, const floa
float iHeight = length(iPos) - rPlanet;
// Calculate the optical depth of the Rayleigh and Mie scattering for this step.
float odStepRlh = exp(-iHeight / nishita_rayleigh_scale) * iStepSize;
float odStepMie = exp(-iHeight / nishita_mie_scale) * iStepSize;
float odStepRlh = exp(-iHeight / nishita_rayleigh_scale) * density.x * iStepSize;
float odStepMie = exp(-iHeight / nishita_mie_scale) * density.y * iStepSize;
// Accumulate optical depth.
iOdRlh += odStepRlh;
@ -109,8 +113,8 @@ vec3 nishita_atmosphere(const vec3 r, const vec3 r0, const vec3 pSun, const floa
float jHeight = length(jPos) - rPlanet;
// Accumulate the optical depth.
jOdRlh += exp(-jHeight / nishita_rayleigh_scale) * jStepSize;
jOdMie += exp(-jHeight / nishita_mie_scale) * jStepSize;
jOdRlh += exp(-jHeight / nishita_rayleigh_scale) * density.x * jStepSize;
jOdMie += exp(-jHeight / nishita_mie_scale) * density.y * jStepSize;
// Increment the secondary ray time.
jTime += jStepSize;

6
blender/arm/material/cycles.py
View file

@ -640,8 +640,12 @@ def to_vec1(v):
return str(v)
def to_vec2(v):
return f'vec2({v[0]}, {v[1]})'
def to_vec3(v):
return 'vec3({0}, {1}, {2})'.format(v[0], v[1], v[2])
return f'vec3({v[0]}, {v[1]}, {v[2]})'
def rgb_to_bw(res_var: vec3str) -> floatstr:

8
blender/arm/material/cycles_nodes/nodes_texture.py
View file

@ -376,7 +376,13 @@ def parse_sky_nishita(node: bpy.types.ShaderNodeTexSky, state: ParserState) -> v
planet_radius = 6360e3 # Earth radius used in Blender
ray_origin_z = planet_radius + node.altitude * 1000
return f'nishita_atmosphere(n, vec3(0, 0, {ray_origin_z}), sunDir, {planet_radius})'
d_air = node.air_density
d_dust = node.dust_density
# Todo: Implement ozone density (ignored for now)
# d_ozone = node.ozone_density
density = c.to_vec2((d_air, d_dust))
return f'nishita_atmosphere(n, vec3(0, 0, {ray_origin_z}), sunDir, {planet_radius}, {density})'
def parse_tex_environment(node: bpy.types.ShaderNodeTexEnvironment, out_socket: bpy.types.NodeSocket, state: ParserState) -> vec3str: