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+ | New file for volumetric

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TheRedShip
2025-01-14 10:27:06 +01:00
parent 1d3627000d
commit 95098711f7
4 changed files with 120 additions and 101 deletions
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89
shaders/compute.glsl
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@ -80,6 +80,8 @@ struct hitInfo
#include "shaders/random.glsl"
#include "shaders/intersect.glsl"
#include "shaders/scatter.glsl"
#include "shaders/light.glsl"
#include "shaders/volumetric.glsl"
Ray portalRay(Ray ray, hitInfo hit)
{
@ -139,68 +141,6 @@ hitInfo traceRay(Ray ray)
return (hit);
}
float sampleHG(float g, inout uint rng_state)
{
if (abs(g) < 0.001)
return 2.0 * randomValue(rng_state) - 1.0;
float sqr_term = (1.0 - g * g) / (1.0 + g - 2.0 * g * randomValue(rng_state));
return (1.0 + g * g - sqr_term * sqr_term) / (2.0 * g);
}
vec3 sampleDirection(vec3 forward, float cos_theta, inout uint rng_state)
{
float phi = 2.0 * M_PI * randomValue(rng_state);
float sin_theta = sqrt(max(0.0, 1.0 - cos_theta * cos_theta));
vec3 dir;
dir.x = sin_theta * cos(phi);
dir.y = sin_theta * sin(phi);
dir.z = cos_theta;
vec3 up = abs(forward.z) < 0.999 ? vec3(0, 0, 1) : vec3(1, 0, 0);
vec3 right = normalize(cross(up, forward));
up = cross(forward, right);
return normalize(
dir.x * right +
dir.y * up +
dir.z * forward
);
}
vec3 sampleLights(vec3 position)
{
vec3 light = vec3(0.0);
for (int i = 0; i < u_objectsNum; i++)
{
GPUObject obj = objects[i];
GPUMaterial mat = materials[obj.mat_index];
if (obj.type == 0 && mat.emission > 0.0)
{
vec3 light_dir = normalize(obj.position - position);
float light_dist = length(obj.position - position);
Ray shadow_ray = Ray(position + light_dir * 0.01, light_dir);
hitInfo shadow_hit = traceRay(shadow_ray);
if (shadow_hit.obj_index == i)
light += mat.emission * mat.color / (light_dist);
}
}
return (light);
}
struct VolumeProperties {
vec3 sigma_a; // absorption coefficient
vec3 sigma_s; // scattering coefficient
vec3 sigma_t; // extinction coefficient
float g; // phase function parameter
};
vec3 pathtrace(Ray ray, inout uint rng_state)
{
vec3 color = vec3(1.0);
@ -218,23 +158,10 @@ vec3 pathtrace(Ray ray, inout uint rng_state)
{
hitInfo hit = traceRay(ray);
float t_scatter = -log(randomValue(rng_state)) / volume.sigma_t.x;
float t_surface = hit.t;
if (t_scatter < t_surface && volume.sigma_t.x > 0.0)
float t_scatter = 0.0;
if (atmosScatter(volume, hit, t_scatter, rng_state))
{
vec3 scatter_pos = ray.origin + ray.direction * t_scatter;
transmittance *= exp(-volume.sigma_t * t_scatter);
color *= volume.sigma_s / volume.sigma_t;
light += transmittance * color * sampleLights(scatter_pos);
float cos_theta = sampleHG(volume.g, rng_state);
vec3 new_dir = sampleDirection(ray.direction, cos_theta, rng_state);
ray.origin = scatter_pos;
ray.direction = new_dir;
calculateVolumetricLight(t_scatter, volume, ray, color, light, transmittance, rng_state);
continue;
}
@ -245,7 +172,7 @@ vec3 pathtrace(Ray ray, inout uint rng_state)
break;
}
transmittance *= exp(-volume.sigma_t * t_surface);
transmittance *= exp(-volume.sigma_t * hit.t);
GPUObject obj = objects[hit.obj_index];
GPUMaterial mat = materials[obj.mat_index];
@ -257,9 +184,7 @@ vec3 pathtrace(Ray ray, inout uint rng_state)
color /= p;
//
color *= mat.color;
light += mat.emission * mat.color;
// light += sampleLights(hit.position);
calculateLightColor(color, light, mat, hit);
if (mat.emission > 0.0)
break;

53
shaders/light.glsl Normal file
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@ -0,0 +1,53 @@
vec3 GetEnvironmentLight(Ray ray)
{
vec3 sun_pos = vec3(-1., 1.0, 0.);
float SunFocus = 1.5;
float SunIntensity = 0.5;
vec3 GroundColour = vec3(0.5, 0.5, 0.5);
vec3 SkyColourHorizon = vec3(135 / 255.0f, 206 / 255.0f, 235 / 255.0f);
vec3 SkyColourZenith = SkyColourHorizon / 2.0;
float skyGradientT = pow(smoothstep(0.0, 0.4, ray.direction.y), 0.35);
float groundToSkyT = smoothstep(-0.01, 0.0, ray.direction.y);
vec3 skyGradient = mix(SkyColourHorizon, SkyColourZenith, skyGradientT);
float sun = pow(max(0, dot(ray.direction, sun_pos.xyz)), SunFocus) * SunIntensity;
// Combine ground, sky, and sun
vec3 composite = mix(GroundColour, skyGradient, groundToSkyT) + sun * int(groundToSkyT >= 1);
return composite;
}
hitInfo traceRay(Ray ray);
vec3 sampleLights(vec3 position)
{
vec3 light = vec3(0.0);
for (int i = 0; i < u_objectsNum; i++)
{
GPUObject obj = objects[i];
GPUMaterial mat = materials[obj.mat_index];
if (obj.type == 0 && mat.emission > 0.0)
{
vec3 light_dir = normalize(obj.position - position);
float light_dist = length(obj.position - position);
Ray shadow_ray = Ray(position + light_dir * 0.01, light_dir);
hitInfo shadow_hit = traceRay(shadow_ray);
if (shadow_hit.obj_index == i)
light += mat.emission * mat.color / (light_dist);
}
}
return (light);
}
void calculateLightColor(inout vec3 color, inout vec3 light, GPUMaterial mat, hitInfo hit)
{
color *= mat.color;
light += mat.emission * mat.color;
// light += sampleLights(hit.position);
}

19
shaders/random.glsl
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@ -35,22 +35,3 @@ vec3 randomHemisphereDirection(vec3 normal, inout uint rng_state)
vec3 direction = randomDirection(rng_state);
return (direction * sign(dot(normal, direction)));
}
vec3 GetEnvironmentLight(Ray ray)
{
vec3 sun_pos = vec3(-1., 1.0, 0.);
float SunFocus = 1.5;
float SunIntensity = 0.5;
vec3 GroundColour = vec3(0.5, 0.5, 0.5);
vec3 SkyColourHorizon = vec3(135 / 255.0f, 206 / 255.0f, 235 / 255.0f);
vec3 SkyColourZenith = SkyColourHorizon / 2.0;
float skyGradientT = pow(smoothstep(0.0, 0.4, ray.direction.y), 0.35);
float groundToSkyT = smoothstep(-0.01, 0.0, ray.direction.y);
vec3 skyGradient = mix(SkyColourHorizon, SkyColourZenith, skyGradientT);
float sun = pow(max(0, dot(ray.direction, sun_pos.xyz)), SunFocus) * SunIntensity;
// Combine ground, sky, and sun
vec3 composite = mix(GroundColour, skyGradient, groundToSkyT) + sun * int(groundToSkyT >= 1);
return composite;
}

60
shaders/volumetric.glsl Normal file
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@ -0,0 +1,60 @@
struct VolumeProperties {
vec3 sigma_a; // absorption coefficient
vec3 sigma_s; // scattering coefficient
vec3 sigma_t; // extinction coefficient
float g; // phase function parameter
};
float sampleHG(float g, inout uint rng_state)
{
if (abs(g) < 0.001)
return 2.0 * randomValue(rng_state) - 1.0;
float sqr_term = (1.0 - g * g) / (1.0 + g - 2.0 * g * randomValue(rng_state));
return (1.0 + g * g - sqr_term * sqr_term) / (2.0 * g);
}
vec3 sampleDirection(vec3 forward, float cos_theta, inout uint rng_state)
{
float phi = 2.0 * M_PI * randomValue(rng_state);
float sin_theta = sqrt(max(0.0, 1.0 - cos_theta * cos_theta));
vec3 dir;
dir.x = sin_theta * cos(phi);
dir.y = sin_theta * sin(phi);
dir.z = cos_theta;
vec3 up = abs(forward.z) < 0.999 ? vec3(0, 0, 1) : vec3(1, 0, 0);
vec3 right = normalize(cross(up, forward));
up = cross(forward, right);
return normalize(
dir.x * right +
dir.y * up +
dir.z * forward
);
}
bool atmosScatter(VolumeProperties volume, hitInfo hit, inout float t_scatter, inout uint rng_state)
{
t_scatter = -log(randomValue(rng_state)) / volume.sigma_t.x;
return (t_scatter < hit.t && volume.sigma_t.x > 0.0);
}
void calculateVolumetricLight(float t_scatter, VolumeProperties volume, inout Ray ray, inout vec3 color, inout vec3 light, inout vec3 transmittance, inout uint rng_state)
{
vec3 scatter_pos = ray.origin + ray.direction * t_scatter;
transmittance *= exp(-volume.sigma_t * t_scatter);
color *= volume.sigma_s / volume.sigma_t;
light += transmittance * color * sampleLights(scatter_pos);
float cos_theta = sampleHG(volume.g, rng_state);
vec3 new_dir = sampleDirection(ray.direction, cos_theta, rng_state);
ray.origin = scatter_pos;
ray.direction = new_dir;
}