This allows selecting the formulas to obtain a better distribution of
values.
rotate_lookup->storage(RGBA8, 4, 4, 1);
resources.add(name, rotate_lookup);
rotate_lookup->storage(RGBA8, 4, 4, 1);
resources.add(name, rotate_lookup);
unsigned char data[64];
for(unsigned i=0; i<16; ++i)
{
unsigned char data[64];
for(unsigned i=0; i<16; ++i)
{
- Geometry::Angle<float> a = Geometry::Angle<float>::from_turns(random(seed));
+ Geometry::Angle<float> a = Geometry::Angle<float>::from_turns(i*7/16.0f);
unsigned char c = (cos(a)*0.5f+0.5f)*255;
unsigned char s = (sin(a)*0.5f+0.5f)*255;
data[i*4 ] = c;
unsigned char c = (cos(a)*0.5f+0.5f)*255;
unsigned char s = (sin(a)*0.5f+0.5f)*255;
data[i*4 ] = c;
-float AmbientOcclusion::random(unsigned &seed)
+float AmbientOcclusion::radical_inverse(unsigned n)
- static const unsigned modulus = (1U<<31)-1;
- seed = (static_cast<UInt64>(seed)*48271)%modulus; // minstd
- return static_cast<float>(seed)/(modulus-1);
+ unsigned inv = ((n&0x55)<<1) | ((n&0xAA)>>1);
+ inv = ((inv&0x33)<<2) | ((inv&0xCC)>>2);
+ inv = ((inv&0x0F)<<4) | ((inv&0xF0)>>4);
+ return inv/256.0f;
}
void AmbientOcclusion::set_n_samples(unsigned n)
}
void AmbientOcclusion::set_n_samples(unsigned n)
if(n<1 || n>32)
throw out_of_range("AmbientOcclusion::set_n_samples");
if(n<1 || n>32)
throw out_of_range("AmbientOcclusion::set_n_samples");
- unsigned seed = 1;
- float radius_divisor = (n-1)*(n-1);
Vector3 sample_points[32];
for(unsigned i=0; i<n; ++i)
{
Vector3 sample_points[32];
for(unsigned i=0; i<n; ++i)
{
- Vector3 v(random(seed)-0.5f, random(seed)-0.5f, random(seed)-0.5f);
- sample_points[i] = normalize(v)*(0.1f+0.9f*i*i/radius_divisor);
+ float z = static_cast<float>(i)/n;
+ float r = sqrt(1.0f-z*z);
+ float d = radical_inverse(i);
+ Geometry::Angle<float> a = Geometry::Angle<float>::from_turns(d);
+ sample_points[i] = Vector3(cos(a)*r, sin(a)*r, z)*(0.1f+0.9f*d*d);
}
shdata.uniform3_array("sample_points", n, &sample_points[0].x);
shdata.uniform("n_samples", static_cast<int>(n));
}
shdata.uniform3_array("sample_points", n, &sample_points[0].x);
shdata.uniform("n_samples", static_cast<int>(n));
private:
static const Texture2D &get_or_create_rotate_lookup();
private:
static const Texture2D &get_or_create_rotate_lookup();
- static float random(unsigned &);
+ static float radical_inverse(unsigned);
public:
void set_n_samples(unsigned);
public:
void set_n_samples(unsigned);