Files
OpenSpace/modules/base/shaders/rings_fs.glsl
2016-08-16 09:41:13 +02:00

94 lines
4.1 KiB
GLSL

/*****************************************************************************************
* *
* OpenSpace *
* *
* Copyright (c) 2014-2016 *
* *
* 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 *
* HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF *
* CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE *
* OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. *
****************************************************************************************/
#include "PowerScaling/powerScaling_fs.hglsl"
#include "fragment.glsl"
in vec2 vs_st;
in vec4 vs_position;
uniform sampler1D texture1;
uniform vec2 textureOffset;
uniform float transparency;
uniform bool hasSunPosition;
uniform vec3 sunPosition;
uniform float _nightFactor;
Fragment getFragment() {
vec4 position = vs_position;
float depth = pscDepth(position);
// Moving the origin to the center
vec2 st = (vs_st - vec2(0.5)) * 2.0;
// The length of the texture coordinates vector is our distance from the center
float radius = length(st);
// We only want to consider ring-like objects so we need to discard everything else
if (radius > 1.0)
discard;
// Remapping the texture coordinates
// Radius \in [0,1], texCoord \in [textureOffset.x, textureOffset.y]
// textureOffset.x -> 0
// textureOffset.y -> 1
float texCoord = (radius - textureOffset.x) / (textureOffset.y - textureOffset.x);
if (texCoord < 0.f || texCoord > 1.f)
discard;
vec4 diffuse = texture(texture1, texCoord);
float colorValue = length(diffuse.rgb);
// times 3 as length of vec3(1.0, 1.0, 1.0) will return 3 and we want
// to normalize the transparency value to [0,1]
if (colorValue < 3*transparency) {
diffuse.a = pow(colorValue / (3*transparency), 1);
}
if (hasSunPosition) {
// The normal for the one plane depends on whether we are dealing
// with a front facing or back facing fragment
vec3 normal;
// The plane is oriented on the xz plane
// WARNING: This might not be the case for Uranus
if (gl_FrontFacing) {
normal = vec3(-1.0, 0.0, 0.0);
}
else {
normal = vec3(1.0, 0.0, 0.0);
}
// Reduce the color of the fragment by the user factor
// if we are facing away from the Sun
if (dot(sunPosition, normal) < 0)
diffuse.xyz *= _nightFactor;
}
Fragment frag;
frag.color = diffuse;
frag.depth = depth;
return frag;
}