Files
OpenSpace/modules/space/shaders/habitablezone_fs.glsl
2024-02-06 15:53:24 +01:00

90 lines
4.0 KiB
GLSL

/*****************************************************************************************
* *
* OpenSpace *
* *
* Copyright (c) 2014-2024 *
* *
* Permission is hereby granted, free of charge, to any person obtaining a copy of this *
* software and associated documentation files (the "Software"), to deal in the Software *
* without restriction, including without limitation the rights to use, copy, modify, *
* merge, publish, distribute, sublicense, and/or sell copies of the Software, and to *
* permit persons to whom the Software is furnished to do so, subject to the following *
* conditions: *
* *
* The above copyright notice and this permission notice shall be included in all copies *
* or substantial portions of the Software. *
* *
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, *
* INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A *
* PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT *
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****************************************************************************************/
#include "fragment.glsl"
in vec2 vs_st;
in float vs_screenSpaceDepth;
uniform sampler1D transferFunctionTexture;
uniform float width;
uniform float opacity;
uniform vec2 conservativeBounds;
uniform bool showOptimistic;
// Remap the radius to texture coordinates in the trasfer function texture. The texture
// is treated as a linear scale where the color represent too cold to too hot. Account
// for the conservative bounds my mapping one third of the texture ouside each boundary.
// All parameters \in [0,1], where 1.0 corresponds to the max radius.
float computeTextureCoord(float radius, float innerRadius,
float conservativeInner, float conservativeOuter)
{
const float t1 = 1.0 / 3.0;
const float t2 = 2.0 / 3.0;
if (radius < conservativeInner) {
float t = (radius - innerRadius) / (conservativeInner - innerRadius);
return mix(0.0, t1, t);
}
else if (radius > conservativeOuter) {
float t = (radius - conservativeOuter) / (1.0 - conservativeOuter);
return mix(t2, 1.0, t);
}
else {
float t = (radius - conservativeInner) / (conservativeOuter - conservativeInner);
return mix(t1, t2, t);
}
}
Fragment getFragment() {
// The length of the texture coordinates vector is our distance from the center
float radius = length(vs_st);
float innerRadius = 1.0 - width;
// We only want to consider ring-like objects so we need to discard everything else
if (radius > 1.0 || radius < innerRadius) {
discard;
}
float consInner = conservativeBounds.x;
float consOuter = conservativeBounds.y;
bool outsideConservative = (radius < consInner) || (radius > consOuter);
if (!showOptimistic && outsideConservative) {
discard;
}
float texCoord = computeTextureCoord(radius, innerRadius, consInner, consOuter);
vec4 diffuse = texture(transferFunctionTexture, texCoord);
diffuse.a *= opacity;
Fragment frag;
frag.color = diffuse;
frag.depth = vs_screenSpaceDepth;
return frag;
}