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etl::sampler - generic interface for sampling
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@blackwarthog
blackwarthog committed Sep 6, 2016
1 parent 1febcaa commit 47b8a53
Showing 1 changed file with 117 additions and 245 deletions.
362 changes: 117 additions & 245 deletions ETL/ETL/_surface.h
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Original file line number Diff line number Diff line change
Expand Up @@ -52,6 +52,109 @@ class value_prep
value_type uncook(const accumulator_type& x)const { return (value_type)x; }
};

template <typename VT, typename CT, typename ST, ST reader(const void*, int, int)>
class sampler
{
public:
typedef VT value_type;
typedef CT coord_type;
typedef ST source_type;
typedef coord_type float_type;

inline static void prepare_coord(int w, const coord_type x, int &u, float_type &a) {
if (x<0) { u=0; a=0; }
else if (x>w-1.00001) { u=w-2; a=1; }
else {
u=floor_to_int(x);
a=float_type(x)-float_type(u);
}
}

inline static void prepare_coords(int w, int h, const coord_type x, const coord_type y, int &u, int &v, float_type &a, float_type &b)
{
prepare_coord(w, x, u, a);
prepare_coord(h, y, v, b);
}

inline static void fill_cubic_polinomial(float_type x, float_type tx[])
{
tx[0] = float_type(0.5)*x*(x*(float_type(-1)*x + float_type(2)) - float_type(1)); // -t + 2t^2 -t^3
tx[1] = float_type(0.5)*(x*(x*(float_type(3)*x - float_type(5))) + float_type(2)); // 2 - 5t^2 + 3t^3
tx[2] = float_type(0.5)*x*(x*(float_type(-3)*x + float_type(4)) + float_type(1)); // t + 4t^2 - 3t^3
tx[3] = float_type(0.5)*x*x*(x-float_type(1)); // -t^2 + t^3
}

//! Linear sample
static value_type linear_sample(const void *surface, int w, int h, const coord_type x, const coord_type y)
{
int u, v; float_type a, b;
prepare_coords(w, h, x, y, u, v, a, b);

const float_type c(float_type(1)-a), d(float_type(1)-b);

return (value_type)(reader(surface, u ,v ))*c*d
+ (value_type)(reader(surface, u+1,v ))*a*d
+ (value_type)(reader(surface, u ,v+1))*c*b
+ (value_type)(reader(surface, u+1,v+1))*a*b;
}

//! Cosine sample
static value_type cosine_sample(const void *surface, int w, int h, const coord_type x, const coord_type y)
{
int u, v; float_type a, b;
prepare_coords(w, h, x, y, u, v, a, b);

a=(float_type(1) - cos(a*float_type(3.1415927)))*float_type(0.5);
b=(float_type(1) - cos(b*float_type(3.1415927)))*float_type(0.5);

const float_type c(float_type(1)-a), d(float_type(1)-b);

return (value_type)(reader(surface, u ,v ))*c*d
+ (value_type)(reader(surface, u+1,v ))*a*d
+ (value_type)(reader(surface, u ,v+1))*c*b
+ (value_type)(reader(surface, u+1,v+1))*a*b;
}

//! Cubic sample
static value_type cubic_sample(const void *surface, int w, int h, const coord_type x, const coord_type y)
{
//Using catmull rom interpolation because it doesn't blur at all
//bezier curve with intermediate ctrl pts: 0.5/3(p(i+1) - p(i-1)) and similar

//precalculate indices (all clamped) and offset
const int xi = (int)floor(x);
const int yi = (int)floor(y);
int xa[] = { xi-1, xi, xi+1, xi+2 };
int ya[] = { yi-1, yi, yi+1, yi+2 };

// clamp all
const int ww = w - 1;
const int hh = h - 1;
xa[0] < 0 && ((xa[1] < 0 && ((xa[2] < 0 && ((xa[3] < 0 && (xa[3] = 0 )), (xa[2] = 0 ))), (xa[1] = 0 ))), (xa[0] = 0 ));
ya[0] < 0 && ((ya[1] < 0 && ((ya[2] < 0 && ((ya[3] < 0 && (ya[3] = 0 )), (ya[2] = 0 ))), (ya[1] = 0 ))), (ya[0] = 0 ));
xa[3] > ww && ((xa[2] > ww && ((xa[1] > ww && ((xa[0] > ww && (xa[0] = ww)), (xa[1] = ww))), (xa[2] = ww))), (xa[3] = ww));
ya[3] > hh && ((ya[2] > hh && ((ya[1] > hh && ((ya[0] > hh && (ya[0] = hh)), (ya[1] = hh))), (ya[2] = hh))), (ya[3] = hh));

// offset
const float_type xf = float_type(x)-float_type(xi);
const float_type yf = float_type(y)-float_type(yi);

float_type txf[4], tyf[4];
fill_cubic_polinomial(xf, txf);
fill_cubic_polinomial(yf, tyf);

#define f(i,j) (value_type)(reader(surface, i, j))
#define ff(i,j) f(xa[i], ya[j])*txf[i]
#define fff(j) (ff(0,j) + ff(1,j) + ff(2,j) + ff(3,j))*tyf[j]

return fff(0) + fff(1) + fff(2) + fff(3);

#undef fff
#undef ff
#undef f
}
};

template <typename T, typename AT=T, class VP=value_prep<T,AT> >
class surface
{
Expand Down Expand Up @@ -382,268 +485,37 @@ class surface
const_pen get_pen(int x, int y)const { assert(data_); return begin().move(x,y); }
const_pen end()const { assert(data_); return get_pen(w_,h_); }

inline static value_type reader(const void *surf, int x, int y)
{ return (*(const surface*)surf)[y][x]; }
inline static accumulator_type reader_cook(const void *surf, int x, int y)
{ return (*(const surface*)surf).cooker_.cook(reader(surf, x, y)); }

typedef sampler<accumulator_type, float, accumulator_type, reader_cook> sampler_cook;
typedef sampler<accumulator_type, float, value_type, reader> sampler_nocook;

//! Linear sample
value_type linear_sample(const float x, const float y)const
{
int u(floor_to_int(x)), v(floor_to_int(y));
float a, b;
static const float epsilon(1.0e-6);

if(x<0.0f)u=0,a=0.0f;
else if(x>w_-1)u=w_-1,a=0.0f;
else a=x-u;

if(y<0.0f)v=0,b=0.0f;
else if(y>h_-1)v=h_-1,b=0.0f;
else b=y-v;

const float
c(1.0f-a), d(1.0f-b),
e(a*d),f(c*b),g(a*b);

accumulator_type ret(cooker_.cook((*this)[v][u])*(c*d));
if(e>=epsilon)ret+=cooker_.cook((*this)[v][u+1])*e;
if(f>=epsilon)ret+=cooker_.cook((*this)[v+1][u])*f;
if(g>=epsilon)ret+=cooker_.cook((*this)[v+1][u+1])*g;
return cooker_.uncook(ret);
}
{ return cooker_.uncook(sampler_cook::linear_sample(this, w_, h_, x, y)); }

//! Linear sample for already "cooked" surfaces
value_type linear_sample_cooked(const float x, const float y)const
{
#define h(j,i) (((accumulator_type)((*this)[j][i])))
int u(floor_to_int(x)), v(floor_to_int(y));
float a, b;
static const float epsilon(1.0e-6);

if(x<0.0f)u=0,a=0.0f;
else if(x>w_-1)u=w_-1,a=0.0f;
else a=x-u;

if(y<0.0f)v=0,b=0.0f;
else if(y>h_-1)v=h_-1,b=0.0f;
else b=y-v;

const float
c(1.0f-a), d(1.0f-b),
e(a*d),f(c*b),g(a*b);

accumulator_type ret(h(v,u)*(c*d));
if(e>=epsilon)ret+=h(v,u+1)*e;
if(f>=epsilon)ret+=h(v+1,u)*f;
if(g>=epsilon)ret+=h(v+1,u+1)*g;

return (value_type)(ret);
#undef h
}
{ return (value_type)(sampler_nocook::linear_sample(this, w_, h_, x, y)); }

//! Cosine sample
value_type cosine_sample(const float x, const float y)const
{
int u(floor_to_int(x)), v(floor_to_int(y));
float a, b;
static const float epsilon(1.0e-6);

if(x<0.0f)u=0,a=0.0f;
else if(x>w_-1)u=w_-1,a=0.0f;
else a=x-u;

if(y<0.0f)v=0,b=0.0f;
else if(y>h_-1)v=h_-1,b=0.0f;
else b=y-v;

a=(1.0f-cos(a*3.1415927f))*0.5f;
b=(1.0f-cos(b*3.1415927f))*0.5f;

const float
c(1.0f-a), d(1.0f-b),
e(a*d),f(c*b),g(a*b);

accumulator_type ret(cooker_.cook((*this)[v][u])*(c*d));
if(e>=epsilon)ret+=cooker_.cook((*this)[v][u+1])*e;
if(f>=epsilon)ret+=cooker_.cook((*this)[v+1][u])*f;
if(g>=epsilon)ret+=cooker_.cook((*this)[v+1][u+1])*g;

return cooker_.uncook(ret);
}
{ return cooker_.uncook(sampler_cook::cosine_sample(this, w_, h_, x, y)); }

//! Cosine sample for already "cooked" surfaces
value_type cosine_sample_cooked(const float x, const float y)const
{
#define h(j,i) (((accumulator_type)((*this)[j][i])))

int u(floor_to_int(x)), v(floor_to_int(y));
float a, b;
static const float epsilon(1.0e-6);

if(x<0.0f)u=0,a=0.0f;
else if(x>w_-1)u=w_-1,a=0.0f;
else a=x-u;

if(y<0.0f)v=0,b=0.0f;
else if(y>h_-1)v=h_-1,b=0.0f;
else b=y-v;

a=(1.0f-cos(a*3.1415927f))*0.5f;
b=(1.0f-cos(b*3.1415927f))*0.5f;

const float
c(1.0f-a), d(1.0f-b),
e(a*d),f(c*b),g(a*b);

accumulator_type ret(h(v,u)*(c*d));
if(e>=epsilon)ret+=h(v,u+1)*e;
if(f>=epsilon)ret+=h(v+1,u)*f;
if(g>=epsilon)ret+=h(v+1,u+1)*g;

return (value_type)(ret);
#undef h
}
{ return (value_type)(sampler_nocook::cosine_sample(this, w_, h_, x, y)); }

//! Cubic sample
value_type cubic_sample(float x, float y)const
{
#if 0
#define P(x) (((x)>=0)?((x)*(x)*(x)):0.0f)
#define R(x) ( P(x+2) - 4.0f*P(x+1) + 6.0f*P(x) - 4.0f*P(x-1) )*(1.0f/6.0f)
#define F(i,j) (cooker_.cook((*this)[max(min(j+v,h_-1),0)][max(min(i+u,w_-1),0)])*(R((i)-a)*R(b-(j))))
#define Z(i,j) ret+=F(i,j)
#define X(i,j) // placeholder... To make box more symmetric

int u(floor_to_int(x)), v(floor_to_int(y));
float a, b;

// Clamp X
if(x<0.0f)u=0,a=0.0f;
else if(u>w_-1)u=w_-1,a=0.0f;
else a=x-u;

// Clamp Y
if(y<0.0f)v=0,b=0.0f;
else if(v>h_-1)v=h_-1,b=0.0f;
else b=y-v;

// Interpolate
accumulator_type ret(F(0,0));
Z(-1,-1); Z(-1, 0); Z(-1, 1); Z(-1, 2);
Z( 0,-1); X( 0, 0); Z( 0, 1); Z( 0, 2);
Z( 1,-1); Z( 1, 0); Z( 1, 1); Z( 1, 2);
Z( 2,-1); Z( 2, 0); Z( 2, 1); Z( 2, 2);

return cooker_.uncook(ret);

#undef X
#undef Z
#undef F
#undef P
#undef R
#else

#define f(j,i) (cooker_.cook((*this)[j][i]))
//Using catmull rom interpolation because it doesn't blur at all
//bezier curve with intermediate ctrl pts: 0.5/3(p(i+1) - p(i-1)) and similar
accumulator_type xfa [4];

//precalculate indices (all clamped) and offset
const int xi = (int)floor(x);
const int yi = (int)floor(y);
int xa[] = { xi-1, xi, xi+1, xi+2 };
int ya[] = { yi-1, yi, yi+1, yi+2 };

// clamp all
const int w = w_ - 1;
const int h = h_ - 1;
xa[0] < 0 && ((xa[1] < 0 && ((xa[2] < 0 && ((xa[3] < 0 && (xa[3] = 0)), (xa[2] = 0))), (xa[1] = 0))), (xa[0] = 0));
ya[0] < 0 && ((ya[1] < 0 && ((ya[2] < 0 && ((ya[3] < 0 && (ya[3] = 0)), (ya[2] = 0))), (ya[1] = 0))), (ya[0] = 0));
xa[3] > w && ((xa[2] > w && ((xa[1] > w && ((xa[0] > w && (xa[0] = w)), (xa[1] = w))), (xa[2] = w))), (xa[3] = w));
ya[3] > h && ((ya[2] > h && ((ya[1] > h && ((ya[0] > h && (ya[0] = h)), (ya[1] = h))), (ya[2] = h))), (ya[3] = h));

// offset
const float xf = x-xi;
const float yf = y-yi;

//figure polynomials for each point
const float txf[] =
{
0.5f*xf*(xf*(xf*(-1.f) + 2.f) - 1.f), //-t + 2t^2 -t^3
0.5f*(xf*(xf*(3.f*xf - 5.f)) + 2.f), //2 - 5t^2 + 3t^3
0.5f*xf*(xf*(-3.f*xf + 4.f) + 1.f), //t + 4t^2 - 3t^3
0.5f*xf*xf*(xf-1.f) //-t^2 + t^3
};

const float tyf[] =
{
0.5f*yf*(yf*(yf*(-1.f) + 2.f) - 1.f), //-t + 2t^2 -t^3
0.5f*(yf*(yf*(3.f*yf - 5.f)) + 2.f), //2 - 5t^2 + 3t^3
0.5f*yf*(yf*(-3.f*yf + 4.f) + 1.f), //t + 4t^2 - 3t^3
0.5f*yf*yf*(yf-1.f) //-t^2 + t^3
};

//evaluate polynomial for each row
for(int i = 0; i < 4; ++i)
{
xfa[i] = f(ya[i],xa[0])*txf[0] + f(ya[i],xa[1])*txf[1] + f(ya[i],xa[2])*txf[2] + f(ya[i],xa[3])*txf[3];
}

//return the cumulative column evaluation
return cooker_.uncook(xfa[0]*tyf[0] + xfa[1]*tyf[1] + xfa[2]*tyf[2] + xfa[3]*tyf[3]);
#undef f
#endif
}
{ return cooker_.uncook(sampler_cook::cubic_sample(this, w_, h_, x, y)); }

//! Cubic sample for already "cooked" surfaces
value_type cubic_sample_cooked(float x, float y)const
{
#define f(j,i) (((accumulator_type)((*this)[j][i])))
//Using catmull rom interpolation because it doesn't blur at all
//bezier curve with intermediate ctrl pts: 0.5/3(p(i+1) - p(i-1)) and similar
accumulator_type xfa [4];

//precalculate indices (all clamped) and offset
const int xi = (int)floor(x);
const int yi = (int)floor(y);
int xa[] = { xi-1, xi, xi+1, xi+2 };
int ya[] = { yi-1, yi, yi+1, yi+2 };

// clamp all
const int w = w_ - 1;
const int h = h_ - 1;
xa[0] < 0 && ((xa[1] < 0 && ((xa[2] < 0 && ((xa[3] < 0 && (xa[3] = 0)), (xa[2] = 0))), (xa[1] = 0))), (xa[0] = 0));
ya[0] < 0 && ((ya[1] < 0 && ((ya[2] < 0 && ((ya[3] < 0 && (ya[3] = 0)), (ya[2] = 0))), (ya[1] = 0))), (ya[0] = 0));
xa[3] > w && ((xa[2] > w && ((xa[1] > w && ((xa[0] > w && (xa[0] = w)), (xa[1] = w))), (xa[2] = w))), (xa[3] = w));
ya[3] > h && ((ya[2] > h && ((ya[1] > h && ((ya[0] > h && (ya[0] = h)), (ya[1] = h))), (ya[2] = h))), (ya[3] = h));

// offset
const float xf = x-xi;
const float yf = y-yi;

//figure polynomials for each point
const float txf[] =
{
0.5f*xf*(xf*(xf*(-1) + 2) - 1), //-t + 2t^2 -t^3
0.5f*(xf*(xf*(3*xf - 5)) + 2), //2 - 5t^2 + 3t^3
0.5f*xf*(xf*(-3*xf + 4) + 1), //t + 4t^2 - 3t^3
0.5f*xf*xf*(xf-1) //-t^2 + t^3
};

const float tyf[] =
{
0.5f*yf*(yf*(yf*(-1.f) + 2.f) - 1.f), //-t + 2t^2 -t^3
0.5f*(yf*(yf*(3.f*yf - 5.f)) + 2.f), //2 - 5t^2 + 3t^3
0.5f*yf*(yf*(-3.f*yf + 4.f) + 1.f), //t + 4t^2 - 3t^3
0.5f*yf*yf*(yf-1.f) //-t^2 + t^3
};

//evaluate polynomial for each row
for(int i = 0; i < 4; ++i)
{
xfa[i] = f(ya[i],xa[0])*txf[0] + f(ya[i],xa[1])*txf[1] + f(ya[i],xa[2])*txf[2] + f(ya[i],xa[3])*txf[3];
}

//return the cumulative column evaluation
return (value_type)(xfa[0]*tyf[0] + xfa[1]*tyf[1] + xfa[2]*tyf[2] + xfa[3]*tyf[3]);
#undef f
}
{ return (value_type)(sampler_nocook::cubic_sample(this, w_, h_, x, y)); }

//! Rectangle sample
value_type sample_rect(float x0,float y0,float x1,float y1) const
Expand Down

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