120 lines
3.6 KiB
GLSL
120 lines
3.6 KiB
GLSL
/**
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* @file sunLightF.glsl
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*
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* $LicenseInfo:firstyear=2007&license=viewerlgpl$
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* Second Life Viewer Source Code
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* Copyright (C) 2007, Linden Research, Inc.
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation;
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* version 2.1 of the License only.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*
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* Linden Research, Inc., 945 Battery Street, San Francisco, CA 94111 USA
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* $/LicenseInfo$
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*/
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#ifdef DEFINE_GL_FRAGCOLOR
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out vec4 frag_color;
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#else
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#define frag_color gl_FragColor
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#endif
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VARYING vec2 vary_fragcoord;
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uniform sampler2D depthMapDownsampled;
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uniform sampler2D normalMap;
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uniform sampler2D noiseMap;
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uniform mat4 inv_proj;
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uniform float ssao_radius;
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uniform float ssao_max_radius;
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uniform float ssao_factor;
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uniform vec2 kern_scale;
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uniform vec2 noise_scale;
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vec3 decode_normal(vec2 enc);
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vec4 getPosition(vec2 pos_screen);
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vec2 getKern(int i)
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{
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vec2 kern[8];
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// exponentially (^2) distant occlusion samples spread around origin
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kern[0] = vec2(-1.0, 0.0) * (0.125*0.125*.9+.1);
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kern[1] = vec2(1.0, 0.0) * (0.250*0.250*.9+.1);
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kern[2] = vec2(0.0, 1.0) * (0.375*0.375*.9+.1);
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kern[3] = vec2(0.0, -1.0) * (0.500*0.500*.9+.1);
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kern[4] = vec2(0.7071, 0.7071) * (0.625*0.625*.9+.1);
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kern[5] = vec2(-0.7071, -0.7071) * (0.750*0.750*.9+.1);
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kern[6] = vec2(-0.7071, 0.7071) * (0.875*0.875*.9+.1);
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kern[7] = vec2(0.7071, -0.7071) * (1.000*1.000*.9+.1);
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return kern[i];
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}
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//calculate decreases in ambient lighting when crowded out (SSAO)
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float calcAmbientOcclusion(vec4 pos, vec3 norm)
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{
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vec2 pos_screen = vary_fragcoord.xy;
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vec2 noise_reflect = texture2D(noiseMap, vary_fragcoord.xy * noise_scale).xy;
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// We treat the first sample as the origin, which definitely doesn't obscure itself thanks to being visible for sampling in the first place.
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float points = 1.0;
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float angle_hidden = 0.0;
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// use a kernel scale that diminishes with distance.
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// a scale of less than 32 is just wasting good samples, though.
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vec2 scale = max(32.0, min(ssao_radius / -pos.z, ssao_max_radius)) * kern_scale;
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// it was found that keeping # of samples a constant was the fastest, probably due to compiler optimizations (unrolling?)
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for (int i = 0; i < 8; i++)
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{
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vec2 samppos_screen = pos_screen + scale * reflect(getKern(i), noise_reflect);
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vec3 samppos_world = getPosition(samppos_screen).xyz;
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vec3 diff = samppos_world - pos.xyz;
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if (diff.z < ssao_factor && diff.z != 0.0)
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{
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float dist = length(diff);
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float angrel = max(0.0, dot(norm.xyz, diff/dist));
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float distrel = 1.0/(1.0+dist*dist);
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float samplehidden = min(angrel, distrel);
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angle_hidden += (samplehidden);
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points += 1.0;
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}
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}
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angle_hidden /= points;
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float rtn = (1.0 - angle_hidden);
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return (rtn * rtn) * (rtn * rtn); //Pow2 to increase darkness to match previous behavior.
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}
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void main()
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{
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vec2 pos_screen = vary_fragcoord.xy;
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//try doing an unproject here
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vec4 pos = getPosition(pos_screen);
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vec3 norm = texture2D(normalMap, pos_screen).xyz;
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norm = decode_normal(norm.xy);
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frag_color = vec4(calcAmbientOcclusion(pos,norm),0,0,0);
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}
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