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HDR: Use precomputed uniforms in the skydome shader

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Fernando García Liñán 2021-08-19 13:09:44 +02:00
parent 1093a3fa97
commit 765a7d88f5
1 changed files with 9 additions and 8 deletions
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17
Shaders/HDR/skydome.frag
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@ -8,12 +8,15 @@ in vec3 vRayDirView;
uniform bool sun_disk;
uniform sampler2D sky_view_lut;
uniform sampler2D transmittance_lut;
uniform vec3 fg_SunDirection;
uniform mat4 osg_ModelViewMatrix;
uniform vec3 fg_SunDirection;
uniform float fg_CameraDistanceToEarthCenter;
uniform float fg_EarthRadius;
uniform vec3 fg_CameraViewUp;
const float PI = 3.141592653;
const vec3 EXTRATERRESTRIAL_SOLAR_ILLUMINANCE = vec3(128.0);
const float ATMOSPHERE_RADIUS = 6471e3;
const float sun_solid_angle = 0.545*PI/180.0; // ~half a degree
const float sun_cos_solid_angle = cos(sun_solid_angle);
@ -35,15 +38,13 @@ void main()
float cosTheta = dot(rayDirView, fg_SunDirection);
if (cosTheta >= sun_cos_solid_angle) {
vec4 groundPoint = osg_ModelViewMatrix * vec4(0.0, 0.0, 0.0, 1.0);
float altitude = length(groundPoint);
float scaledAltitude = altitude / 100000.0;
float normalizedHeight = (fg_CameraDistanceToEarthCenter - fg_EarthRadius)
/ (ATMOSPHERE_RADIUS - fg_EarthRadius);
vec3 up = normalize(vec3(0.0, 0.0, 0.0) - groundPoint.xyz);
float sunZenithCosTheta = dot(rayDirView, up);
float sunZenithCosTheta = dot(-rayDirView, fg_CameraViewUp);
vec2 coords = vec2(sunZenithCosTheta * 0.5 + 0.5,
clamp(scaledAltitude, 0.0, 1.0));
clamp(normalizedHeight, 0.0, 1.0));
vec3 transmittance = texture(transmittance_lut, coords).rgb;
// Limb darkening