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uniform sampler2D u_ScreenDepthMap;
uniform sampler2D u_ShadowMap;
#if defined(USE_SHADOW_CASCADE)
uniform sampler2D u_ShadowMap2;
uniform sampler2D u_ShadowMap3;
#endif
uniform mat4 u_ShadowMvp;
#if defined(USE_SHADOW_CASCADE)
uniform mat4 u_ShadowMvp2;
uniform mat4 u_ShadowMvp3;
#endif
uniform vec3 u_ViewOrigin;
uniform vec4 u_ViewInfo; // zfar / znear, zfar
varying vec2 var_DepthTex;
varying vec3 var_ViewDir;
// depth is GL_DEPTH_COMPONENT24
// so the maximum error is 1.0 / 2^24
#define DEPTH_MAX_ERROR 0.000000059604644775390625
// Input: It uses texture coords as the random number seed.
// Output: Random number: [0,1), that is between 0.0 and 0.999999... inclusive.
// Author: Michael Pohoreski
// Copyright: Copyleft 2012 :-)
// Source: http://stackoverflow.com/questions/5149544/can-i-generate-a-random-number-inside-a-pixel-shader
float random( const vec2 p )
{
// We need irrationals for pseudo randomness.
// Most (all?) known transcendental numbers will (generally) work.
const vec2 r = vec2(
23.1406926327792690, // e^pi (Gelfond's constant)
2.6651441426902251); // 2^sqrt(2) (Gelfond-Schneider constant)
//return fract( cos( mod( 123456789., 1e-7 + 256. * dot(p,r) ) ) );
return mod( 123456789., 1e-7 + 256. * dot(p,r) );
}
float PCF(const sampler2D shadowmap, const vec2 st, const float dist)
{
float mult;
float scale = 2.0 / r_shadowMapSize;
#if defined(USE_SHADOW_FILTER)
float r = random(var_DepthTex.xy);
float sinr = sin(r) * scale;
float cosr = cos(r) * scale;
mat2 rmat = mat2(cosr, sinr, -sinr, cosr);
mult = step(dist, texture2D(shadowmap, st + rmat * vec2(-0.7055767, 0.196515)).r);
mult += step(dist, texture2D(shadowmap, st + rmat * vec2(0.3524343, -0.7791386)).r);
mult += step(dist, texture2D(shadowmap, st + rmat * vec2(0.2391056, 0.9189604)).r);
#if defined(USE_SHADOW_FILTER2)
mult += step(dist, texture2D(shadowmap, st + rmat * vec2(-0.07580382, -0.09224417)).r);
mult += step(dist, texture2D(shadowmap, st + rmat * vec2(0.5784913, -0.002528916)).r);
mult += step(dist, texture2D(shadowmap, st + rmat * vec2(0.192888, 0.4064181)).r);
mult += step(dist, texture2D(shadowmap, st + rmat * vec2(-0.6335801, -0.5247476)).r);
mult += step(dist, texture2D(shadowmap, st + rmat * vec2(-0.5579782, 0.7491854)).r);
mult += step(dist, texture2D(shadowmap, st + rmat * vec2(0.7320465, 0.6317794)).r);
mult *= 0.11111;
#else
mult *= 0.33333;
#endif
#else
mult = step(dist, texture2D(shadowmap, st).r);
#endif
return mult;
}
float getLinearDepth(sampler2D depthMap, vec2 tex, float zFarDivZNear)
{
float sampleZDivW = texture2D(depthMap, tex).r;
sampleZDivW -= DEPTH_MAX_ERROR;
return 1.0 / mix(zFarDivZNear, 1.0, sampleZDivW);
}
void main()
{
float result;
float depth = getLinearDepth(u_ScreenDepthMap, var_DepthTex, u_ViewInfo.x);
float sampleZ = u_ViewInfo.y * depth;
vec4 biasPos = vec4(u_ViewOrigin + var_ViewDir * (depth - 0.5 / u_ViewInfo.x), 1.0);
vec4 shadowpos = u_ShadowMvp * biasPos;
#if defined(USE_SHADOW_CASCADE)
const float fadeTo = 1.0;
result = fadeTo;
#else
result = 0.0;
#endif
if (all(lessThanEqual(abs(shadowpos.xyz), vec3(abs(shadowpos.w)))))
{
shadowpos.xyz = shadowpos.xyz / shadowpos.w * 0.5 + 0.5;
result = PCF(u_ShadowMap, shadowpos.xy, shadowpos.z);
}
#if defined(USE_SHADOW_CASCADE)
else
{
shadowpos = u_ShadowMvp2 * biasPos;
if (all(lessThanEqual(abs(shadowpos.xyz), vec3(abs(shadowpos.w)))))
{
shadowpos.xyz = shadowpos.xyz / shadowpos.w * 0.5 + 0.5;
result = PCF(u_ShadowMap2, shadowpos.xy, shadowpos.z);
}
else
{
shadowpos = u_ShadowMvp3 * biasPos;
if (all(lessThanEqual(abs(shadowpos.xyz), vec3(abs(shadowpos.w)))))
{
shadowpos.xyz = shadowpos.xyz / shadowpos.w * 0.5 + 0.5;
result = PCF(u_ShadowMap3, shadowpos.xy, shadowpos.z);
float fade = clamp(sampleZ / r_shadowCascadeZFar * 10.0 - 9.0, 0.0, 1.0);
result = mix(result, fadeTo, fade);
}
}
}
#endif
gl_FragColor = vec4(vec3(result), 1.0);
}
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