shadowUtil.glsl

/** 
 * @file class1/deferred/shadowUtil.glsl
 *
 * $LicenseInfo:firstyear=2007&license=viewerlgpl$
 * Second Life Viewer Source Code
 * Copyright (C) 2007, 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
 * $/LicenseInfo$
 */

uniform sampler2DRect   normalMap;
uniform sampler2DRect   depthMap;
uniform sampler2DShadow shadowMap0;
uniform sampler2DShadow shadowMap1;
uniform sampler2DShadow shadowMap2;
uniform sampler2DShadow shadowMap3;
uniform sampler2DShadow shadowMap4;
uniform sampler2DShadow shadowMap5;

uniform vec3 sun_dir;
uniform vec3 moon_dir;
uniform vec2 shadow_res;
uniform vec2 proj_shadow_res;
uniform mat4 shadow_matrix[6];
uniform vec4 shadow_clip;
uniform float shadow_bias;
uniform float shadow_offset;
uniform float spot_shadow_bias;
uniform float spot_shadow_offset;
uniform mat4 inv_proj;
uniform vec2 screen_res;
uniform int sun_up_factor;

float pcfShadow(sampler2DShadow shadowMap, vec3 norm, vec4 stc, float bias_mul, vec2 pos_screen, vec3 light_dir)
{
    float offset = shadow_bias * bias_mul;
    stc.xyz /= stc.w;
    stc.z += offset * 2.0;
    stc.x = floor(stc.x*shadow_res.x + fract(pos_screen.y*shadow_res.y))/shadow_res.x; // add some chaotic jitter to X sample pos according to Y to disguise the snapping going on here
    float cs = shadow2D(shadowMap, stc.xyz).x;
    float shadow = cs * 4.0;
    shadow += shadow2D(shadowMap, stc.xyz+vec3( 1.5/shadow_res.x,  0.5/shadow_res.y, 0.0)).x;
    shadow += shadow2D(shadowMap, stc.xyz+vec3( 0.5/shadow_res.x, -1.5/shadow_res.y, 0.0)).x;
    shadow += shadow2D(shadowMap, stc.xyz+vec3(-1.5/shadow_res.x, -0.5/shadow_res.y, 0.0)).x;
    shadow += shadow2D(shadowMap, stc.xyz+vec3(-0.5/shadow_res.x,  1.5/shadow_res.y, 0.0)).x;
    return clamp(shadow * 0.125, 0.0, 1.0);
}

float pcfSpotShadow(sampler2DShadow shadowMap, vec4 stc, float bias_scale, vec2 pos_screen)
{
    stc.xyz /= stc.w;
    stc.z += spot_shadow_bias * bias_scale;
    stc.x = floor(proj_shadow_res.x * stc.x + fract(pos_screen.y*0.666666666)) / proj_shadow_res.x; // snap

    float cs = shadow2D(shadowMap, stc.xyz).x;