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/**
* @file sunLightSSAOF.glsl
*
* Copyright (c) 2007-$CurrentYear$, Linden Research, Inc.
* $License$
*/
#extension GL_ARB_texture_rectangle : enable
#extension GL_ARB_texture_multisample : enable
//class 2 -- shadows and SSAO
uniform sampler2DMS depthMap;
uniform sampler2DMS normalMap;
uniform sampler2DRectShadow shadowMap0;
uniform sampler2DRectShadow shadowMap1;
uniform sampler2DRectShadow shadowMap2;
uniform sampler2DRectShadow shadowMap3;
uniform sampler2DShadow shadowMap4;
uniform sampler2DShadow shadowMap5;
uniform sampler2D noiseMap;
// Inputs
uniform mat4 shadow_matrix[6];
uniform vec4 shadow_clip;
uniform float ssao_radius;
uniform float ssao_max_radius;
uniform float ssao_factor;
uniform float ssao_factor_inv;
varying vec2 vary_fragcoord;
varying vec4 vary_light;
uniform mat4 inv_proj;
uniform vec2 screen_res;
uniform vec2 shadow_res;
uniform vec2 proj_shadow_res;
uniform float shadow_bias;
uniform float shadow_offset;
uniform float spot_shadow_bias;
uniform float spot_shadow_offset;
vec4 getPosition(ivec2 pos_screen, int sample)
{
float depth = texelFetch(depthMap, pos_screen, sample).r;
vec2 sc = vec2(pos_screen.xy)*2.0;
sc /= screen_res;
sc -= vec2(1.0,1.0);
vec4 ndc = vec4(sc.x, sc.y, 2.0*depth-1.0, 1.0);
vec4 pos = inv_proj * ndc;
pos /= pos.w;
pos.w = 1.0;
return pos;
}
//calculate decreases in ambient lighting when crowded out (SSAO)
float calcAmbientOcclusion(vec4 pos, vec3 norm, int sample)
{
float ret = 1.0;
vec2 kern[8];
// exponentially (^2) distant occlusion samples spread around origin
kern[0] = vec2(-1.0, 0.0) * 0.125*0.125;
kern[1] = vec2(1.0, 0.0) * 0.250*0.250;
kern[2] = vec2(0.0, 1.0) * 0.375*0.375;
kern[3] = vec2(0.0, -1.0) * 0.500*0.500;
kern[4] = vec2(0.7071, 0.7071) * 0.625*0.625;
kern[5] = vec2(-0.7071, -0.7071) * 0.750*0.750;
kern[6] = vec2(-0.7071, 0.7071) * 0.875*0.875;
kern[7] = vec2(0.7071, -0.7071) * 1.000*1.000;
vec2 pos_screen = vary_fragcoord.xy;
vec3 pos_world = pos.xyz;
vec2 noise_reflect = texture2D(noiseMap, vary_fragcoord.xy/128.0).xy;
float angle_hidden = 0.0;
int points = 0;
float scale = min(ssao_radius / -pos_world.z, ssao_max_radius);
// it was found that keeping # of samples a constant was the fastest, probably due to compiler optimizations (unrolling?)
for (int i = 0; i < 8; i++)
{
ivec2 samppos_screen = ivec2(pos_screen + scale * reflect(kern[i], noise_reflect));
vec3 samppos_world = getPosition(samppos_screen, sample).xyz;
vec3 diff = pos_world - samppos_world;
float dist2 = dot(diff, diff);
// assume each sample corresponds to an occluding sphere with constant radius, constant x-sectional area
// --> solid angle shrinking by the square of distance
//radius is somewhat arbitrary, can approx with just some constant k * 1 / dist^2
//(k should vary inversely with # of samples, but this is taken care of later)
angle_hidden = angle_hidden + float(dot((samppos_world - 0.05*norm - pos_world), norm) > 0.0) * min(1.0/dist2, ssao_factor_inv);
// 'blocked' samples (significantly closer to camera relative to pos_world) are "no data", not "no occlusion"
points = points + int(diff.z > -1.0);
}
angle_hidden = min(ssao_factor*angle_hidden/float(points), 1.0);
ret = (1.0 - (float(points != 0) * angle_hidden));
return min(ret, 1.0);
}
float pcfShadow(sampler2DRectShadow shadowMap, vec4 stc, float scl)
{
stc.xyz /= stc.w;
stc.z += shadow_bias*scl;
float cs = shadow2DRect(shadowMap, stc.xyz).x;
float shadow = cs;
shadow += max(shadow2DRect(shadowMap, stc.xyz+vec3(1.5, 1.5, 0.0)).x, cs);
shadow += max(shadow2DRect(shadowMap, stc.xyz+vec3(1.5, -1.5, 0.0)).x, cs);
shadow += max(shadow2DRect(shadowMap, stc.xyz+vec3(-1.5, 1.5, 0.0)).x, cs);
shadow += max(shadow2DRect(shadowMap, stc.xyz+vec3(-1.5, -1.5, 0.0)).x, cs);
return shadow/5.0;
//return shadow;
}
float pcfShadow(sampler2DShadow shadowMap, vec4 stc, float scl)
{
stc.xyz /= stc.w;
stc.z += spot_shadow_bias*scl;
float cs = shadow2D(shadowMap, stc.xyz).x;
float shadow = cs;
vec2 off = 1.5/proj_shadow_res;
shadow += max(shadow2D(shadowMap, stc.xyz+vec3(off.x, off.y, 0.0)).x, cs);
shadow += max(shadow2D(shadowMap, stc.xyz+vec3(off.x, -off.y, 0.0)).x, cs);
shadow += max(shadow2D(shadowMap, stc.xyz+vec3(-off.x, off.y, 0.0)).x, cs);
shadow += max(shadow2D(shadowMap, stc.xyz+vec3(-off.x, -off.y, 0.0)).x, cs);
return shadow/5.0;
//return shadow;
}
void main()
{
vec2 pos_screen = vary_fragcoord.xy;
ivec2 itc = ivec2(pos_screen);
vec4 fcol = vec4(0,0,0,0);
for (int i = 0; i < samples; i++)
{
vec4 pos = getPosition(itc, i);
vec4 nmap4 = texelFetch(normalMap, itc, i);
nmap4 = vec4((nmap4.xy-0.5)*2.0,nmap4.z,nmap4.w); // unpack norm
float displace = nmap4.w;
vec3 norm = nmap4.xyz;
float shadow = 1.0;
float dp_directional_light = max(0.0, dot(norm, vary_light.xyz));
vec3 shadow_pos = pos.xyz + displace*norm;
vec3 offset = vary_light.xyz * (1.0-dp_directional_light);
vec4 spos = vec4(shadow_pos+offset*shadow_offset, 1.0);
if (spos.z > -shadow_clip.w)
{
if (dp_directional_light == 0.0)
{
// if we know this point is facing away from the sun then we know it's in shadow without having to do a squirrelly shadow-map lookup
shadow = 0.0;
}
else
{
vec4 lpos;
if (spos.z < -shadow_clip.z)
{
lpos = shadow_matrix[3]*spos;
lpos.xy *= shadow_res;
shadow = pcfShadow(shadowMap3, lpos, 0.25);
shadow += max((pos.z+shadow_clip.z)/(shadow_clip.z-shadow_clip.w)*2.0-1.0, 0.0);
}
else if (spos.z < -shadow_clip.y)
{
lpos = shadow_matrix[2]*spos;
lpos.xy *= shadow_res;
shadow = pcfShadow(shadowMap2, lpos, 0.5);
}
else if (spos.z < -shadow_clip.x)
{
lpos = shadow_matrix[1]*spos;
lpos.xy *= shadow_res;
shadow = pcfShadow(shadowMap1, lpos, 0.75);
}
else
{
lpos = shadow_matrix[0]*spos;
lpos.xy *= shadow_res;
shadow = pcfShadow(shadowMap0, lpos, 1.0);
}
// take the most-shadowed value out of these two:
// * the blurred sun shadow in the light (shadow) map
// * an unblurred dot product between the sun and this norm
// the goal is to err on the side of most-shadow to fill-in shadow holes and reduce artifacting
shadow = min(shadow, dp_directional_light);
}
}
else
{
// more distant than the shadow map covers
shadow = 1.0;
}
fcol[0] += shadow;
fcol[1] += calcAmbientOcclusion(pos, norm, i);
spos.xyz = shadow_pos+offset*spot_shadow_offset;
//spotlight shadow 1
vec4 lpos = shadow_matrix[4]*spos;
fcol[2] += pcfShadow(shadowMap4, lpos, 0.8);
//spotlight shadow 2
lpos = shadow_matrix[5]*spos;
fcol[3] += pcfShadow(shadowMap5, lpos, 0.8);
}
gl_FragColor = fcol / samples;
}
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