Add comments to BC7CompressionMode.h

This commit is contained in:
Pavel Krajcevski 2013-03-20 23:27:17 -04:00
parent a19f83d123
commit 921c3e9f16

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@ -74,171 +74,211 @@ struct VisitedState;
const int kMaxEndpoints = 3;
static const int kPBits[4][2] = {
{ 0, 0 },
{ 0, 1 },
{ 1, 0 },
{ 1, 1 }
{ 0, 0 },
{ 0, 1 },
{ 1, 0 },
{ 1, 1 }
};
// Abstract class that outlines all of the different settings for BC7 compression modes
// Note that at the moment, we only support modes 0-3, so we don't deal with alpha channels.
class BC7CompressionMode {
public:
static const uint32 kMaxNumSubsets = 3;
static const uint32 kNumModes = 8;
public:
explicit BC7CompressionMode(int mode, bool opaque = true) : m_IsOpaque(opaque), m_Attributes(&(kModeAttributes[mode])), m_RotateMode(0), m_IndexMode(0) { }
~BC7CompressionMode() { }
static const uint32 kMaxNumSubsets = 3;
static const uint32 kNumModes = 8;
double Compress(BitStream &stream, const int shapeIdx, const RGBACluster *clusters);
// This initializes the compression variables used in order to compress a list of clusters.
// We can increase the speed a tad by specifying whether or not the block is opaque or not.
explicit BC7CompressionMode(int mode, bool opaque = true)
: m_IsOpaque(opaque)
, m_Attributes(&(kModeAttributes[mode]))
, m_RotateMode(0)
, m_IndexMode(0)
{ }
~BC7CompressionMode() { }
// This switch controls the quality of the simulated annealing optimizer. We will not make
// more than this many steps regardless of how bad the error is. Higher values will produce
// better quality results but will run slower. Default is 20.
static int MaxAnnealingIterations; // This is a setting
static const int kMaxAnnealingIterations = 256; // This is a limit
// This function compresses a group of clusters into the passed bitstream. The size of the
// clusters array is determined by the BC7 compression mode.
double Compress(BitStream &stream, const int shapeIdx, const RGBACluster *clusters);
enum EPBitType {
ePBitType_Shared,
ePBitType_NotShared,
ePBitType_None
};
// This switch controls the quality of the simulated annealing optimizer. We will not make
// more than this many steps regardless of how bad the error is. Higher values will produce
// better quality results but will run slower. Default is 20.
static int MaxAnnealingIterations; // This is a setting
static const int kMaxAnnealingIterations = 256; // This is a limit
static struct Attributes {
int modeNumber;
int numPartitionBits;
int numSubsets;
int numBitsPerIndex;
int numBitsPerAlpha;
int colorChannelPrecision;
int alphaChannelPrecision;
bool hasRotation;
bool hasIdxMode;
EPBitType pbitType;
} kModeAttributes[kNumModes];
// P-bits are low-order bits that are shared across color channels. This enum says whether or not
// both endpoints share a p-bit or whether or not they even have a p-bit.
enum EPBitType {
ePBitType_Shared,
ePBitType_NotShared,
ePBitType_None
};
static const Attributes *GetAttributesForMode(int mode) {
if(mode < 0 || mode >= 8) return NULL;
return &kModeAttributes[mode];
}
// These are all the per-mode attributes that can be set. They are specified in a table
// and we access them through the private m_Attributes variable.
static struct Attributes {
int modeNumber;
int numPartitionBits;
int numSubsets;
int numBitsPerIndex;
int numBitsPerAlpha;
int colorChannelPrecision;
int alphaChannelPrecision;
bool hasRotation;
bool hasIdxMode;
EPBitType pbitType;
} kModeAttributes[kNumModes];
private:
// This returns the above attributes structure for the given mode.
static const Attributes *GetAttributesForMode(int mode) {
if(mode < 0 || mode >= 8) return NULL;
return &kModeAttributes[mode];
}
const double m_IsOpaque;
const Attributes *const m_Attributes;
private:
int m_RotateMode;
int m_IndexMode;
const double m_IsOpaque;
const Attributes *const m_Attributes;
void SetIndexMode(int mode) { m_IndexMode = mode; }
void SetRotationMode(int mode) { m_RotateMode = mode; }
int m_RotateMode;
int m_IndexMode;
int GetRotationMode() const { return m_Attributes->hasRotation? m_RotateMode : 0; }
void SetIndexMode(int mode) { m_IndexMode = mode; }
void SetRotationMode(int mode) { m_RotateMode = mode; }
int GetModeNumber() const { return m_Attributes->modeNumber; }
int GetNumberOfPartitionBits() const { return m_Attributes->numPartitionBits; }
int GetNumberOfSubsets() const { return m_Attributes->numSubsets; }
int GetRotationMode() const { return m_Attributes->hasRotation? m_RotateMode : 0; }
int GetModeNumber() const { return m_Attributes->modeNumber; }
int GetNumberOfBitsPerIndex(int indexMode = -1) const {
if(indexMode < 0) indexMode = m_IndexMode;
if(indexMode == 0)
return m_Attributes->numBitsPerIndex;
else
return m_Attributes->numBitsPerAlpha;
}
int GetNumberOfPartitionBits() const { return m_Attributes->numPartitionBits; }
int GetNumberOfSubsets() const { return m_Attributes->numSubsets; }
int GetNumberOfBitsPerAlpha(int indexMode = -1) const {
if(indexMode < 0) indexMode = m_IndexMode;
if(indexMode == 0)
return m_Attributes->numBitsPerAlpha;
else
return m_Attributes->numBitsPerIndex;
}
int GetNumberOfBitsPerIndex(int indexMode = -1) const {
if(indexMode < 0) indexMode = m_IndexMode;
if(indexMode == 0)
return m_Attributes->numBitsPerIndex;
else
return m_Attributes->numBitsPerAlpha;
}
// If we handle alpha separately, then we will consider the alpha channel
// to be not used whenever we do any calculations...
int GetAlphaChannelPrecision() const {
return m_Attributes->alphaChannelPrecision;
}
int GetNumberOfBitsPerAlpha(int indexMode = -1) const {
if(indexMode < 0) indexMode = m_IndexMode;
if(indexMode == 0)
return m_Attributes->numBitsPerAlpha;
else
return m_Attributes->numBitsPerIndex;
}
RGBAVector GetErrorMetric() const {
const float *w = BC7C::GetErrorMetric();
switch(GetRotationMode()) {
default:
case 0: return RGBAVector(w[0], w[1], w[2], w[3]);
case 1: return RGBAVector(w[3], w[1], w[2], w[0]);
case 2: return RGBAVector(w[0], w[3], w[2], w[1]);
case 3: return RGBAVector(w[0], w[1], w[3], w[2]);
}
}
// If we handle alpha separately, then we will consider the alpha channel
// to be not used whenever we do any calculations...
int GetAlphaChannelPrecision() const {
return m_Attributes->alphaChannelPrecision;
}
EPBitType GetPBitType() const { return m_Attributes->pbitType; }
// This returns the proper error metric even if we have rotation bits set
RGBAVector GetErrorMetric() const {
const float *w = BC7C::GetErrorMetric();
switch(GetRotationMode()) {
default:
case 0: return RGBAVector(w[0], w[1], w[2], w[3]);
case 1: return RGBAVector(w[3], w[1], w[2], w[0]);
case 2: return RGBAVector(w[0], w[3], w[2], w[1]);
case 3: return RGBAVector(w[0], w[1], w[3], w[2]);
}
}
unsigned int GetQuantizationMask() const {
const int maskSeed = 0x80000000;
const uint32 alphaPrec = GetAlphaChannelPrecision();
if(alphaPrec > 0) {
return (
(maskSeed >> (24 + m_Attributes->colorChannelPrecision - 1) & 0xFF) |
(maskSeed >> (16 + m_Attributes->colorChannelPrecision - 1) & 0xFF00) |
(maskSeed >> (8 + m_Attributes->colorChannelPrecision - 1) & 0xFF0000) |
(maskSeed >> (GetAlphaChannelPrecision() - 1) & 0xFF000000)
);
}
else {
return (
((maskSeed >> (24 + m_Attributes->colorChannelPrecision - 1) & 0xFF) |
(maskSeed >> (16 + m_Attributes->colorChannelPrecision - 1) & 0xFF00) |
(maskSeed >> (8 + m_Attributes->colorChannelPrecision - 1) & 0xFF0000)) &
(0x00FFFFFF)
);
}
}
EPBitType GetPBitType() const { return m_Attributes->pbitType; }
int GetNumPbitCombos() const {
switch(GetPBitType()) {
case ePBitType_Shared: return 2;
case ePBitType_NotShared: return 4;
default:
case ePBitType_None: return 1;
}
}
// This function creates an integer that represents the maximum values in each
// channel. We can use this to figure out the proper endpoint values for a given
// mode.
unsigned int GetQuantizationMask() const {
const int maskSeed = 0x80000000;
const uint32 alphaPrec = GetAlphaChannelPrecision();
if(alphaPrec > 0) {
return (
(maskSeed >> (24 + m_Attributes->colorChannelPrecision - 1) & 0xFF) |
(maskSeed >> (16 + m_Attributes->colorChannelPrecision - 1) & 0xFF00) |
(maskSeed >> (8 + m_Attributes->colorChannelPrecision - 1) & 0xFF0000) |
(maskSeed >> (GetAlphaChannelPrecision() - 1) & 0xFF000000)
);
}
else {
return (
((maskSeed >> (24 + m_Attributes->colorChannelPrecision - 1) & 0xFF) |
(maskSeed >> (16 + m_Attributes->colorChannelPrecision - 1) & 0xFF00) |
(maskSeed >> (8 + m_Attributes->colorChannelPrecision - 1) & 0xFF0000)) &
(0x00FFFFFF)
);
}
}
const int *GetPBitCombo(int idx) const {
switch(GetPBitType()) {
case ePBitType_Shared: return (idx)? kPBits[3] : kPBits[0];
case ePBitType_NotShared: return kPBits[idx % 4];
default:
case ePBitType_None: return kPBits[0];
}
}
int GetNumPbitCombos() const {
switch(GetPBitType()) {
case ePBitType_Shared: return 2;
case ePBitType_NotShared: return 4;
default:
case ePBitType_None: return 1;
}
}
double OptimizeEndpointsForCluster(
const int *GetPBitCombo(int idx) const {
switch(GetPBitType()) {
case ePBitType_Shared: return (idx)? kPBits[3] : kPBits[0];
case ePBitType_NotShared: return kPBits[idx % 4];
default:
case ePBitType_None: return kPBits[0];
}
}
// This performs simulated annealing on the endpoints p1 and p2 based on the
// current MaxAnnealingIterations. This is set by calling the function
// SetQualityLevel
double OptimizeEndpointsForCluster(
const RGBACluster &cluster,
RGBAVector &p1, RGBAVector &p2,
int *bestIndices,
int &bestPbitCombo
) const;
void PickBestNeighboringEndpoints(
const RGBACluster &cluster,
const RGBAVector &p1, const RGBAVector &p2,
const int curPbitCombo,
RGBAVector &np1, RGBAVector &np2,
int &nPbitCombo,
const VisitedState *visitedStates,
int nVisited,
float stepSz = 1.0f
) const;
// This function performs the heuristic to choose the "best" neighboring
// endpoints to p1 and p2 based on the compression mode (index precision,
// endpoint precision etc)
void PickBestNeighboringEndpoints(
const RGBACluster &cluster,
const RGBAVector &p1, const RGBAVector &p2,
const int curPbitCombo,
RGBAVector &np1, RGBAVector &np2,
int &nPbitCombo,
const VisitedState *visitedStates,
int nVisited,
float stepSz = 1.0f
) const;
bool AcceptNewEndpointError(double newError, double oldError, float temp) const;
// This is used by simulated annealing to determine whether or not the newError
// (from the neighboring endpoints) is sufficient to continue the annealing process
// from these new endpoints based on how good the oldError was, and how long we've
// been annealing (temp)
bool AcceptNewEndpointError(double newError, double oldError, float temp) const;
double CompressSingleColor(const RGBAVector &p, RGBAVector &p1, RGBAVector &p2, int &bestPbitCombo) const;
double CompressCluster(const RGBACluster &cluster, RGBAVector &p1, RGBAVector &p2, int *bestIndices, int &bestPbitCombo) const;
double CompressCluster(const RGBACluster &cluster, RGBAVector &p1, RGBAVector &p2, int *bestIndices, int *alphaIndices) const;
// This function figures out the best compression for the single color p, and places
// the endpoints in p1 and p2. If the compression mode supports p-bits, then we
// choose the best p-bit combo and return it as well.
double CompressSingleColor(const RGBAVector &p, RGBAVector &p1, RGBAVector &p2, int &bestPbitCombo) const;
void ClampEndpointsToGrid(RGBAVector &p1, RGBAVector &p2, int &bestPBitCombo) const;
// Compress the cluster using a generalized cluster fit. This figures out the proper endpoints
// assuming that we have no alpha.
double CompressCluster(const RGBACluster &cluster, RGBAVector &p1, RGBAVector &p2, int *bestIndices, int &bestPbitCombo) const;
// Compress the non-opaque cluster using a generalized cluster fit, and place the
// endpoints within p1 and p2. The color indices and alpha indices are computed as well.
double CompressCluster(const RGBACluster &cluster, RGBAVector &p1, RGBAVector &p2, int *bestIndices, int *alphaIndices) const;
// This function takes two endpoints in the continuous domain (as floats) and clamps them
// to the nearest grid points based on the compression mode (and possible pbit values)
void ClampEndpointsToGrid(RGBAVector &p1, RGBAVector &p2, int &bestPBitCombo) const;
};
extern const uint32 kBC7InterpolationValues[4][16][2];