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Fixed black stripe at dark part of atmosphere circumference. Also, gamma corrected atmopshere.

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This commit is contained in:
AnotherCommander 2019-03-07 20:51:10 +01:00
parent 0e2ea8896a
commit cdaf689263
1 changed files with 21 additions and 9 deletions
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30
Resources/Shaders/oolite-default-atmosphere.fragment
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@ -37,7 +37,7 @@ varying vec3 vLight1Vector;
const vec3 biasColor = vec3(0.0, 0.0, 1.0);
const vec3 kTerminatorThreshold = vec3(0.105, 0.18, 0.28); // old: vec3(0.1, 0.105, 0.12);
const float kFresnelExponent = 4.0;
const float biasColorMixRatio = 0.1;
const float biasColorMixRatio = 0.35;
void main()
@ -51,11 +51,12 @@ void main()
vec3 diffuseColor = DIFFUSE_LIGHT;
float NdotV = clamp(dot(normal, eyeVector), 0.0, 1.0);
float NdotL = max(0.0, dot(light1Vector, normal));
float atmDistance = length(atmPosition.xyz);
float minDistance = atmRadius + 3500.0;
float magicDistance = atmDistance - minDistance;
float cosThreshold = 0.14; // 81.95 deg
float cosThreshold = 0.15; // 81.37 deg
float newOpacityExponent = 3.0;
// the outer atmosphere rim does not follow exactly the curvature of the planet for small radii
@ -70,13 +71,12 @@ void main()
// mix in some light blue color
totalColor += diffuseColor * vec3(0.85, 0.85, 1.0);
// create a fresnel torus around the planet
vec3 fresnel = vec3(pow(1.0 - (NdotV * 0.3), kFresnelExponent));
// get the fresnel lit up from the correct direction
vec3 invLight = vec3(dot(light1Vector, normal));
totalColor *= dot(normalize(fresnel), invLight) *
mix(totalColor, biasColor, biasColorMixRatio) *
// mix the bias color now
totalColor *= mix(totalColor, biasColor, biasColorMixRatio) *
// uncomment below for fresnel to affect atmosphere color
//dot(normalize(fresnel), vec3(NdotL)) *
clamp(totalColor, vec3(0.0), diffuseColor);
// magic herebelow - painting the orange-reddish tinted terminator
@ -92,11 +92,23 @@ void main()
float quant = atmDistance < (minDistance + 2000.0) ?
magicDistance / 2000.0 : 1.0;
// create a fresnel torus around the planet - opacity is proportional to it
// multiply NdotV by a constant less than 1.0 to create haze
//vec3 fresnel = vec3(pow(1.0 - (NdotV * 0.3), kFresnelExponent));
// calculate the final opacity, special handling for
// angles > arccos(cosThreshold) to fade atmosphere out at its edge
float newOpacity = quant * (NdotV > cosThreshold ?
float newOpacity = quant * max(0.01, NdotL) * (NdotV > cosThreshold ?
fresnel.r * cosThreshold / NdotV :
pow(NdotV / cosThreshold, newOpacityExponent));
// all above calculations were done in linear space - tonemap & go to sRGB for display
// using Jim Hejl's filmic tonemapping and gamma correction approximation.
// Normally this would require HDR, but I think it works extremely well in Oolite.
// Formula taken from https://www.gdcvault.com/play/1012351/Uncharted-2-HDR
// jump to 27:40 in the video. Note the pow 1.0/2.2 is baked into these numbers
vec3 x = max(vec3(0.0), totalColor - 0.004);
totalColor = (x * (6.2 * x + 0.5)) / (x * (6.2 * x + 1.7) + 0.06);
gl_FragColor = vec4(totalColor, newOpacity);
}