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/**
* @file class1/deferred/skyF.glsl
*
* $LicenseInfo:firstyear=2005&license=viewerlgpl$
* Second Life Viewer Source Code
* Copyright (C) 2005, Linden Research, Inc.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation;
* version 2.1 of the License only.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*
* Linden Research, Inc., 945 Battery Street, San Francisco, CA 94111 USA
* $/LicenseInfo$
*/
// Inputs
in vec3 vary_HazeColor;
in float vary_LightNormPosDot;
uniform sampler2D rainbow_map;
uniform sampler2D halo_map;
uniform float moisture_level;
uniform float droplet_radius;
uniform float ice_level;
out vec4 frag_data[4];
vec3 srgb_to_linear(vec3 c);
/////////////////////////////////////////////////////////////////////////
// The fragment shader for the sky
/////////////////////////////////////////////////////////////////////////
vec3 rainbow(float d)
{
// 'Interesting' values of d are -0.75 .. -0.825, i.e. when view vec nearly opposite of sun vec
// Rainbox tex is mapped with REPEAT, so -.75 as tex coord is same as 0.25. -0.825 -> 0.175. etc.
// SL-13629
// Unfortunately the texture is inverted, so we need to invert the y coord, but keep the 'interesting'
// part within the same 0.175..0.250 range, i.e. d = (1 - d) - 1.575
d = clamp(-0.575 - d, 0.0, 1.0);
// With the colors in the lower 1/4 of the texture, inverting the coords leaves most of it inaccessible.
// So, we can stretch the texcoord above the colors (ie > 0.25) to fill the entire remaining coordinate
// space. This improves gradation, reduces banding within the rainbow interior. (1-0.25) / (0.425/0.25) = 4.2857
float interior_coord = max(0.0, d - 0.25) * 4.2857;
d = clamp(d, 0.0, 0.25) + interior_coord;
float rad = (droplet_radius - 5.0f) / 1024.0f;
return pow(texture(rainbow_map, vec2(rad+0.5, d)).rgb, vec3(1.8)) * moisture_level;
}
vec3 halo22(float d)
{
d = clamp(d, 0.1, 1.0);
float v = sqrt(clamp(1 - (d * d), 0, 1));
return texture(halo_map, vec2(0, v)).rgb * ice_level;
}
void main()
{
// Potential Fill-rate optimization. Add cloud calculation
// back in and output alpha of 0 (so that alpha culling kills
// the fragment) if the sky wouldn't show up because the clouds
// are fully opaque.
vec3 color = vary_HazeColor;
float rel_pos_lightnorm = vary_LightNormPosDot;
float optic_d = rel_pos_lightnorm;
vec3 halo_22 = halo22(optic_d);
color.rgb += rainbow(optic_d);
color.rgb += halo_22;
color.rgb *= 2.;
color.rgb = clamp(color.rgb, vec3(0), vec3(5));
frag_data[0] = vec4(0);
frag_data[1] = vec4(0);
frag_data[2] = vec4(0.0,0.0,0.0,GBUFFER_FLAG_SKIP_ATMOS); //1.0 in norm.w masks off fog
frag_data[3] = vec4(color.rgb, 1.0);
}
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