crossxtex/DirectXTex/Filters.h
2016-09-08 19:09:46 -07:00

422 lines
12 KiB
C++

//-------------------------------------------------------------------------------------
// filters.h
//
// Utility header with helpers for implementing image filters
//
// THIS CODE AND INFORMATION IS PROVIDED "AS IS" WITHOUT WARRANTY OF
// ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO
// THE IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A
// PARTICULAR PURPOSE.
//
// Copyright (c) Microsoft Corporation. All rights reserved.
//-------------------------------------------------------------------------------------
#pragma once
#include <directxmath.h>
#include <directxpackedvector.h>
#include <memory>
#include "scoped.h"
namespace DirectX
{
//-------------------------------------------------------------------------------------
// Box filtering helpers
//-------------------------------------------------------------------------------------
XMGLOBALCONST XMVECTORF32 g_boxScale = { 0.25f, 0.25f, 0.25f, 0.25f };
XMGLOBALCONST XMVECTORF32 g_boxScale3D = { 0.125f, 0.125f, 0.125f, 0.125f };
#define AVERAGE4( res, p0, p1, p2, p3 ) \
{ \
XMVECTOR v = XMVectorAdd( (p0), (p1) ); \
v = XMVectorAdd( v, (p2) ); \
v = XMVectorAdd( v, (p3) ); \
res = XMVectorMultiply( v, g_boxScale ); \
}
#define AVERAGE8( res, p0, p1, p2, p3, p4, p5, p6, p7) \
{ \
XMVECTOR v = XMVectorAdd( (p0), (p1) ); \
v = XMVectorAdd( v, (p2) ); \
v = XMVectorAdd( v, (p3) ); \
v = XMVectorAdd( v, (p4) ); \
v = XMVectorAdd( v, (p5) ); \
v = XMVectorAdd( v, (p6) ); \
v = XMVectorAdd( v, (p7) ); \
res = XMVectorMultiply( v, g_boxScale3D ); \
}
//-------------------------------------------------------------------------------------
// Linear filtering helpers
//-------------------------------------------------------------------------------------
struct LinearFilter
{
size_t u0;
float weight0;
size_t u1;
float weight1;
};
inline void _CreateLinearFilter(_In_ size_t source, _In_ size_t dest, _In_ bool wrap, _Out_writes_(dest) LinearFilter* lf)
{
assert(source > 0);
assert(dest > 0);
assert(lf != 0);
float scale = float(source) / float(dest);
// Mirror is the same case as clamp for linear
for (size_t u = 0; u < dest; ++u)
{
float srcB = (float(u) + 0.5f) * scale + 0.5f;
ptrdiff_t isrcB = ptrdiff_t(srcB);
ptrdiff_t isrcA = isrcB - 1;
if (isrcA < 0)
{
isrcA = (wrap) ? (source - 1) : 0;
}
if (size_t(isrcB) >= source)
{
isrcB = (wrap) ? 0 : (source - 1);
}
float weight = 1.0f + float(isrcB) - srcB;
auto& entry = lf[u];
entry.u0 = size_t(isrcA);
entry.weight0 = weight;
entry.u1 = size_t(isrcB);
entry.weight1 = 1.0f - weight;
}
}
#define BILINEAR_INTERPOLATE( res, x, y, r0, r1 ) \
res = ( y.weight0 * ( (r0)[ x.u0 ] * x.weight0 + (r0)[ x.u1 ] * x.weight1 ) ) \
+ ( y.weight1 * ( (r1)[ x.u0 ] * x.weight0 + (r1)[ x.u1 ] * x.weight1 ) )
#define TRILINEAR_INTERPOLATE( res, x, y, z, r0, r1, r2, r3 ) \
res = ( z.weight0 * ( ( y.weight0 * ( (r0)[ x.u0 ] * x.weight0 + (r0)[ x.u1 ] * x.weight1 ) ) \
+ ( y.weight1 * ( (r1)[ x.u0 ] * x.weight0 + (r1)[ x.u1 ] * x.weight1 ) ) ) ) \
+ ( z.weight1 * ( ( y.weight0 * ( (r2)[ x.u0 ] * x.weight0 + (r2)[ x.u1 ] * x.weight1 ) ) \
+ ( y.weight1 * ( (r3)[ x.u0 ] * x.weight0 + (r3)[ x.u1 ] * x.weight1 ) ) ) )
//-------------------------------------------------------------------------------------
// Cubic filtering helpers
//-------------------------------------------------------------------------------------
XMGLOBALCONST XMVECTORF32 g_cubicThird = { 1.f/3.f, 1.f/3.f, 1.f/3.f, 1.f/3.f };
XMGLOBALCONST XMVECTORF32 g_cubicSixth = { 1.f/6.f, 1.f/6.f, 1.f/6.f, 1.f/6.f };
XMGLOBALCONST XMVECTORF32 g_cubicHalf = { 1.f/2.f, 1.f/2.f, 1.f/2.f, 1.f/2.f };
inline ptrdiff_t bounduvw(ptrdiff_t u, ptrdiff_t maxu, bool wrap, bool mirror)
{
if (wrap)
{
if (u < 0)
{
u = maxu + u + 1;
}
else if (u > maxu)
{
u = u - maxu - 1;
}
}
else if (mirror)
{
if (u < 0)
{
u = (-u) - 1;
}
else if (u > maxu)
{
u = maxu - (u - maxu - 1);
}
}
// Handles clamp, but also a safety factor for degenerate images for wrap/mirror
u = std::min<ptrdiff_t>(u, maxu);
u = std::max<ptrdiff_t>(u, 0);
return u;
}
struct CubicFilter
{
size_t u0;
size_t u1;
size_t u2;
size_t u3;
float x;
};
inline void _CreateCubicFilter(_In_ size_t source, _In_ size_t dest, _In_ bool wrap, _In_ bool mirror, _Out_writes_(dest) CubicFilter* cf)
{
assert(source > 0);
assert(dest > 0);
assert(cf != 0);
float scale = float(source) / float(dest);
for (size_t u = 0; u < dest; ++u)
{
float srcB = (float(u) + 0.5f) * scale - 0.5f;
ptrdiff_t isrcB = bounduvw(ptrdiff_t(srcB), source - 1, wrap, mirror);
ptrdiff_t isrcA = bounduvw(isrcB - 1, source - 1, wrap, mirror);
ptrdiff_t isrcC = bounduvw(isrcB + 1, source - 1, wrap, mirror);
ptrdiff_t isrcD = bounduvw(isrcB + 2, source - 1, wrap, mirror);
auto& entry = cf[u];
entry.u0 = size_t(isrcA);
entry.u1 = size_t(isrcB);
entry.u2 = size_t(isrcC);
entry.u3 = size_t(isrcD);
float x = srcB - float(isrcB);
entry.x = x;
}
}
#define CUBIC_INTERPOLATE( res, dx, p0, p1, p2, p3 ) \
{ \
XMVECTOR a0 = (p1); \
XMVECTOR d0 = (p0) - a0; \
XMVECTOR d2 = (p2) - a0; \
XMVECTOR d3 = (p3) - a0; \
XMVECTOR a1 = d2 - g_cubicThird*d0 - g_cubicSixth*d3; \
XMVECTOR a2 = g_cubicHalf*d0 + g_cubicHalf*d2; \
XMVECTOR a3 = g_cubicSixth*d3 - g_cubicSixth*d0 - g_cubicHalf*d2; \
XMVECTOR vdx = XMVectorReplicate( dx ); \
XMVECTOR vdx2 = vdx * vdx; \
XMVECTOR vdx3 = vdx2 * vdx; \
res = a0 + a1*vdx + a2*vdx2 + a3*vdx3; \
}
//-------------------------------------------------------------------------------------
// Triangle filtering helpers
//-------------------------------------------------------------------------------------
namespace TriangleFilter
{
struct FilterTo
{
size_t u;
float weight;
};
struct FilterFrom
{
size_t count;
size_t sizeInBytes;
FilterTo to[1]; // variable-sized array
};
struct Filter
{
size_t sizeInBytes;
size_t totalSize;
FilterFrom from[1]; // variable-sized array
};
struct TriangleRow
{
size_t remaining;
TriangleRow* next;
ScopedAlignedArrayXMVECTOR scanline;
TriangleRow() : remaining(0), next(nullptr) {}
};
static const size_t TF_FILTER_SIZE = sizeof(Filter) - sizeof(FilterFrom);
static const size_t TF_FROM_SIZE = sizeof(FilterFrom) - sizeof(FilterTo);
static const size_t TF_TO_SIZE = sizeof(FilterTo);
static const float TF_EPSILON = 0.00001f;
inline HRESULT _Create(_In_ size_t source, _In_ size_t dest, _In_ bool wrap, _Inout_ std::unique_ptr<Filter>& tf)
{
assert(source > 0);
assert(dest > 0);
float scale = float(dest) / float(source);
float scaleInv = 0.5f / scale;
// Determine storage required for filter and allocate memory if needed
size_t totalSize = TF_FILTER_SIZE + TF_FROM_SIZE + TF_TO_SIZE;
float repeat = (wrap) ? 1.f : 0.f;
for (size_t u = 0; u < source; ++u)
{
float src = float(u) - 0.5f;
float destMin = src * scale;
float destMax = destMin + scale;
totalSize += TF_FROM_SIZE + TF_TO_SIZE + size_t(destMax - destMin + repeat + 1.f) * TF_TO_SIZE * 2;
}
uint8_t* pFilter = nullptr;
if (tf)
{
// See if existing filter memory block is large enough to reuse
if (tf->totalSize >= totalSize)
{
pFilter = reinterpret_cast<uint8_t*>(tf.get());
}
else
{
// Need to reallocate filter memory block
tf.reset(nullptr);
}
}
if (!tf)
{
// Allocate filter memory block
pFilter = new (std::nothrow) uint8_t[totalSize];
if (!pFilter)
return E_OUTOFMEMORY;
tf.reset(reinterpret_cast<Filter*>(pFilter));
tf->totalSize = totalSize;
}
assert(pFilter != 0);
// Filter setup
size_t sizeInBytes = TF_FILTER_SIZE;
size_t accumU = 0;
float accumWeight = 0.f;
for (size_t u = 0; u < source; ++u)
{
// Setup from entry
size_t sizeFrom = sizeInBytes;
auto pFrom = reinterpret_cast<FilterFrom*>(pFilter + sizeInBytes);
sizeInBytes += TF_FROM_SIZE;
if (sizeInBytes > totalSize)
return E_FAIL;
size_t toCount = 0;
// Perform two passes to capture the influences from both sides
for (size_t j = 0; j < 2; ++j)
{
float src = float(u + j) - 0.5f;
float destMin = src * scale;
float destMax = destMin + scale;
if (!wrap)
{
// Clamp
if (destMin < 0.f)
destMin = 0.f;
if (destMax > float(dest))
destMax = float(dest);
}
for (auto k = static_cast<ptrdiff_t>(floorf(destMin)); float(k) < destMax; ++k)
{
float d0 = float(k);
float d1 = d0 + 1.f;
size_t u0;
if (k < 0)
{
// Handle wrap
u0 = size_t(k + ptrdiff_t(dest));
}
else if (k >= ptrdiff_t(dest))
{
// Handle wrap
u0 = size_t(k - ptrdiff_t(dest));
}
else
{
u0 = size_t(k);
}
// Save previous accumulated weight (if any)
if (u0 != accumU)
{
if (accumWeight > TF_EPSILON)
{
auto pTo = reinterpret_cast<FilterTo*>(pFilter + sizeInBytes);
sizeInBytes += TF_TO_SIZE;
++toCount;
if (sizeInBytes > totalSize)
return E_FAIL;
pTo->u = accumU;
pTo->weight = accumWeight;
}
accumWeight = 0.f;
accumU = u0;
}
// Clip destination
if (d0 < destMin)
d0 = destMin;
if (d1 > destMax)
d1 = destMax;
// Calculate average weight over destination pixel
float weight;
if (!wrap && src < 0.f)
weight = 1.f;
else if (!wrap && ((src + 1.f) >= float(source)))
weight = 0.f;
else
weight = (d0 + d1) * scaleInv - src;
accumWeight += (d1 - d0) * (j ? (1.f - weight) : weight);
}
}
// Store accumulated weight
if (accumWeight > TF_EPSILON)
{
auto pTo = reinterpret_cast<FilterTo*>(pFilter + sizeInBytes);
sizeInBytes += TF_TO_SIZE;
++toCount;
if (sizeInBytes > totalSize)
return E_FAIL;
pTo->u = accumU;
pTo->weight = accumWeight;
}
accumWeight = 0.f;
// Finalize from entry
pFrom->count = toCount;
pFrom->sizeInBytes = sizeInBytes - sizeFrom;
}
tf->sizeInBytes = sizeInBytes;
return S_OK;
}
}; // namespace TriangleFilter
}; // namespace DirectX