137 lines
4 KiB
GLSL
137 lines
4 KiB
GLSL
#version 120
|
|
|
|
uniform sampler2DShadow shadow_tex;
|
|
|
|
uniform bool shadows_enabled;
|
|
uniform int sun_atlas_size;
|
|
|
|
varying vec4 lightSpacePos[4];
|
|
|
|
const bool DEBUG_CASCADES = false;
|
|
|
|
const float DEPTH_BIAS = 1.5;
|
|
|
|
// Ideally these should be passed as an uniform, but we don't support uniform
|
|
// arrays yet
|
|
const vec2 uv_shifts[4] = vec2[4](
|
|
vec2(0.0, 0.0), vec2(0.5, 0.0),
|
|
vec2(0.0, 0.5), vec2(0.5, 0.5));
|
|
const vec2 uv_factor = vec2(0.5, 0.5);
|
|
|
|
|
|
float debugCascade(int cascade)
|
|
{
|
|
const mat2 bayer_matrix = mat2(0, 3, 2, 1);
|
|
const float scale = 0.2;
|
|
vec2 coords = mod(gl_FragCoord.xy * scale, 2.0);
|
|
int threshold = int(bayer_matrix[int(coords.x)][int(coords.y)]);
|
|
if (threshold < cascade)
|
|
return 0.0;
|
|
return 1.0;
|
|
}
|
|
|
|
float checkWithinBounds(vec2 coords, vec2 bottomLeft, vec2 topRight)
|
|
{
|
|
vec2 r = step(bottomLeft, coords) - step(topRight, coords);
|
|
return r.x * r.y;
|
|
}
|
|
|
|
float sampleOffset(vec4 pos, vec2 offset, vec2 invTexelSize)
|
|
{
|
|
return shadow2DProj(
|
|
shadow_tex, vec4(
|
|
pos.xy + offset * invTexelSize * pos.w,
|
|
pos.z - DEPTH_BIAS * invTexelSize.x,
|
|
pos.w)).r;
|
|
}
|
|
|
|
// OptimizedPCF from https://github.com/TheRealMJP/Shadows
|
|
// Original by Ignacio Castaño for The Witness
|
|
// Released under The MIT License
|
|
float sampleOptimizedPCF(vec4 pos)
|
|
{
|
|
vec2 invTexelSize = vec2(1.0 / float(sun_atlas_size));
|
|
|
|
vec2 uv = pos.xy * sun_atlas_size;
|
|
vec2 base_uv = floor(uv + 0.5);
|
|
float s = (uv.x + 0.5 - base_uv.x);
|
|
float t = (uv.y + 0.5 - base_uv.y);
|
|
base_uv -= vec2(0.5);
|
|
base_uv *= invTexelSize;
|
|
pos.xy = base_uv.xy;
|
|
|
|
float sum = 0.0;
|
|
|
|
float uw0 = (4.0 - 3.0 * s);
|
|
float uw1 = 7.0;
|
|
float uw2 = (1.0 + 3.0 * s);
|
|
|
|
float u0 = (3.0 - 2.0 * s) / uw0 - 2.0;
|
|
float u1 = (3.0 + s) / uw1;
|
|
float u2 = s / uw2 + 2.0;
|
|
|
|
float vw0 = (4.0 - 3.0 * t);
|
|
float vw1 = 7.0;
|
|
float vw2 = (1.0 + 3.0 * t);
|
|
|
|
float v0 = (3.0 - 2.0 * t) / vw0 - 2.0;
|
|
float v1 = (3.0 + t) / vw1;
|
|
float v2 = t / vw2 + 2.0;
|
|
|
|
sum += uw0 * vw0 * sampleOffset(pos, vec2(u0, v0), invTexelSize);
|
|
sum += uw1 * vw0 * sampleOffset(pos, vec2(u1, v0), invTexelSize);
|
|
sum += uw2 * vw0 * sampleOffset(pos, vec2(u2, v0), invTexelSize);
|
|
|
|
sum += uw0 * vw1 * sampleOffset(pos, vec2(u0, v1), invTexelSize);
|
|
sum += uw1 * vw1 * sampleOffset(pos, vec2(u1, v1), invTexelSize);
|
|
sum += uw2 * vw1 * sampleOffset(pos, vec2(u2, v1), invTexelSize);
|
|
|
|
sum += uw0 * vw2 * sampleOffset(pos, vec2(u0, v2), invTexelSize);
|
|
sum += uw1 * vw2 * sampleOffset(pos, vec2(u1, v2), invTexelSize);
|
|
sum += uw2 * vw2 * sampleOffset(pos, vec2(u2, v2), invTexelSize);
|
|
|
|
return sum / 144.0;
|
|
}
|
|
|
|
float sampleShadowMap(int n)
|
|
{
|
|
float s = 1.0;
|
|
if (n < 4) {
|
|
vec4 pos = lightSpacePos[n];
|
|
pos.xy *= uv_factor;
|
|
pos.xy += uv_shifts[n];
|
|
s = sampleOptimizedPCF(pos);
|
|
}
|
|
return s;
|
|
}
|
|
|
|
// Get a value between 0.0 and 1.0 where 0.0 means shadowed and 1.0 means lit
|
|
float getShadowing()
|
|
{
|
|
if (!shadows_enabled)
|
|
return 1.0;
|
|
|
|
const float band_size = 0.2;
|
|
const vec2 bandBottomLeft = vec2(band_size);
|
|
const vec2 bandTopRight = vec2(1.0 - band_size);
|
|
|
|
for (int i = 0; i < 4; ++i) {
|
|
if (checkWithinBounds(lightSpacePos[i].xy, vec2(0.0), vec2(1.0)) > 0.0 &&
|
|
(lightSpacePos[i].z / lightSpacePos[i].w) <= 1.0) {
|
|
float debug_value = 0.0;
|
|
if (DEBUG_CASCADES)
|
|
debug_value = debugCascade(i);
|
|
|
|
if (checkWithinBounds(lightSpacePos[i].xy, bandBottomLeft, bandTopRight) < 1.0) {
|
|
vec2 s =
|
|
smoothstep(vec2(0.0), bandBottomLeft, lightSpacePos[i].xy) -
|
|
smoothstep(bandTopRight, vec2(1.0), lightSpacePos[i].xy);
|
|
float blend = 1.0 - s.x * s.y;
|
|
return clamp(mix(sampleShadowMap(i), sampleShadowMap(i+1), blend) - debug_value, 0.0, 1.0);
|
|
}
|
|
return clamp(sampleShadowMap(i) - debug_value, 0.0, 1.0);
|
|
}
|
|
}
|
|
|
|
return 1.0;
|
|
}
|