--- /dev/null
+//-------------------------------------------------------------------------------------
+// BC.cpp
+//
+// Block-compression (BC) functionality for BC1, BC2, BC3 (orginal DXTn formats)
+//
+// 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.
+//
+// http://go.microsoft.com/fwlink/?LinkId=248926
+//-------------------------------------------------------------------------------------
+
+#include "directxtexp.h"
+
+// Experiemental encoding variants, not enabled by default
+//#define COLOR_WEIGHTS
+//#define COLOR_AVG_0WEIGHTS
+
+#include "BC.h"
+
+namespace DirectX
+{
+
+//-------------------------------------------------------------------------------------
+// Constants
+//-------------------------------------------------------------------------------------
+
+// Perceptual weightings for the importance of each channel.
+static const HDRColorA g_Luminance (0.2125f / 0.7154f, 1.0f, 0.0721f / 0.7154f, 1.0f);
+static const HDRColorA g_LuminanceInv(0.7154f / 0.2125f, 1.0f, 0.7154f / 0.0721f, 1.0f);
+
+//-------------------------------------------------------------------------------------
+// Decode/Encode RGB 5/6/5 colors
+//-------------------------------------------------------------------------------------
+inline static void Decode565(_Out_ HDRColorA *pColor, _In_ const uint16_t w565)
+{
+ pColor->r = (float) ((w565 >> 11) & 31) * (1.0f / 31.0f);
+ pColor->g = (float) ((w565 >> 5) & 63) * (1.0f / 63.0f);
+ pColor->b = (float) ((w565 >> 0) & 31) * (1.0f / 31.0f);
+ pColor->a = 1.0f;
+}
+
+inline static uint16_t Encode565(_In_ const HDRColorA *pColor)
+{
+ HDRColorA Color;
+
+ Color.r = (pColor->r < 0.0f) ? 0.0f : (pColor->r > 1.0f) ? 1.0f : pColor->r;
+ Color.g = (pColor->g < 0.0f) ? 0.0f : (pColor->g > 1.0f) ? 1.0f : pColor->g;
+ Color.b = (pColor->b < 0.0f) ? 0.0f : (pColor->b > 1.0f) ? 1.0f : pColor->b;
+
+ uint16_t w;
+
+ w = (uint16_t) ((static_cast<int32_t>(Color.r * 31.0f + 0.5f) << 11) |
+ (static_cast<int32_t>(Color.g * 63.0f + 0.5f) << 5) |
+ (static_cast<int32_t>(Color.b * 31.0f + 0.5f) << 0));
+
+ return w;
+}
+
+
+//-------------------------------------------------------------------------------------
+static void OptimizeRGB(_Out_ HDRColorA *pX, _Out_ HDRColorA *pY,
+ _In_count_c_(NUM_PIXELS_PER_BLOCK) const HDRColorA *pPoints, _In_ size_t cSteps, _In_ DWORD flags)
+{
+ static const float fEpsilon = (0.25f / 64.0f) * (0.25f / 64.0f);
+ static const float pC3[] = { 2.0f/2.0f, 1.0f/2.0f, 0.0f/2.0f };
+ static const float pD3[] = { 0.0f/2.0f, 1.0f/2.0f, 2.0f/2.0f };
+ static const float pC4[] = { 3.0f/3.0f, 2.0f/3.0f, 1.0f/3.0f, 0.0f/3.0f };
+ static const float pD4[] = { 0.0f/3.0f, 1.0f/3.0f, 2.0f/3.0f, 3.0f/3.0f };
+
+ const float *pC = (3 == cSteps) ? pC3 : pC4;
+ const float *pD = (3 == cSteps) ? pD3 : pD4;
+
+ // Find Min and Max points, as starting point
+ HDRColorA X = (flags & BC_FLAGS_UNIFORM) ? HDRColorA(1.f, 1.f, 1.f, 1.f) : g_Luminance;
+ HDRColorA Y = HDRColorA(0.0f, 0.0f, 0.0f, 1.0f);
+
+ for(size_t iPoint = 0; iPoint < NUM_PIXELS_PER_BLOCK; iPoint++)
+ {
+#ifdef COLOR_WEIGHTS
+ if(pPoints[iPoint].a > 0.0f)
+#endif // COLOR_WEIGHTS
+ {
+ if(pPoints[iPoint].r < X.r)
+ X.r = pPoints[iPoint].r;
+
+ if(pPoints[iPoint].g < X.g)
+ X.g = pPoints[iPoint].g;
+
+ if(pPoints[iPoint].b < X.b)
+ X.b = pPoints[iPoint].b;
+
+ if(pPoints[iPoint].r > Y.r)
+ Y.r = pPoints[iPoint].r;
+
+ if(pPoints[iPoint].g > Y.g)
+ Y.g = pPoints[iPoint].g;
+
+ if(pPoints[iPoint].b > Y.b)
+ Y.b = pPoints[iPoint].b;
+ }
+ }
+
+ // Diagonal axis
+ HDRColorA AB;
+
+ AB.r = Y.r - X.r;
+ AB.g = Y.g - X.g;
+ AB.b = Y.b - X.b;
+
+ float fAB = AB.r * AB.r + AB.g * AB.g + AB.b * AB.b;
+
+ // Single color block.. no need to root-find
+ if(fAB < FLT_MIN)
+ {
+ pX->r = X.r; pX->g = X.g; pX->b = X.b;
+ pY->r = Y.r; pY->g = Y.g; pY->b = Y.b;
+ return;
+ }
+
+ // Try all four axis directions, to determine which diagonal best fits data
+ float fABInv = 1.0f / fAB;
+
+ HDRColorA Dir;
+ Dir.r = AB.r * fABInv;
+ Dir.g = AB.g * fABInv;
+ Dir.b = AB.b * fABInv;
+
+ HDRColorA Mid;
+ Mid.r = (X.r + Y.r) * 0.5f;
+ Mid.g = (X.g + Y.g) * 0.5f;
+ Mid.b = (X.b + Y.b) * 0.5f;
+
+ float fDir[4];
+ fDir[0] = fDir[1] = fDir[2] = fDir[3] = 0.0f;
+
+
+ for(size_t iPoint = 0; iPoint < NUM_PIXELS_PER_BLOCK; iPoint++)
+ {
+ HDRColorA Pt;
+ Pt.r = (pPoints[iPoint].r - Mid.r) * Dir.r;
+ Pt.g = (pPoints[iPoint].g - Mid.g) * Dir.g;
+ Pt.b = (pPoints[iPoint].b - Mid.b) * Dir.b;
+
+ float f;
+
+#ifdef COLOR_WEIGHTS
+ f = Pt.r + Pt.g + Pt.b;
+ fDir[0] += pPoints[iPoint].a * f * f;
+
+ f = Pt.r + Pt.g - Pt.b;
+ fDir[1] += pPoints[iPoint].a * f * f;
+
+ f = Pt.r - Pt.g + Pt.b;
+ fDir[2] += pPoints[iPoint].a * f * f;
+
+ f = Pt.r - Pt.g - Pt.b;
+ fDir[3] += pPoints[iPoint].a * f * f;
+#else
+ f = Pt.r + Pt.g + Pt.b;
+ fDir[0] += f * f;
+
+ f = Pt.r + Pt.g - Pt.b;
+ fDir[1] += f * f;
+
+ f = Pt.r - Pt.g + Pt.b;
+ fDir[2] += f * f;
+
+ f = Pt.r - Pt.g - Pt.b;
+ fDir[3] += f * f;
+#endif // COLOR_WEIGHTS
+ }
+
+ float fDirMax = fDir[0];
+ size_t iDirMax = 0;
+
+ for(size_t iDir = 1; iDir < 4; iDir++)
+ {
+ if(fDir[iDir] > fDirMax)
+ {
+ fDirMax = fDir[iDir];
+ iDirMax = iDir;
+ }
+ }
+
+ if(iDirMax & 2)
+ {
+ float f = X.g; X.g = Y.g; Y.g = f;
+ }
+
+ if(iDirMax & 1)
+ {
+ float f = X.b; X.b = Y.b; Y.b = f;
+ }
+
+
+ // Two color block.. no need to root-find
+ if(fAB < 1.0f / 4096.0f)
+ {
+ pX->r = X.r; pX->g = X.g; pX->b = X.b;
+ pY->r = Y.r; pY->g = Y.g; pY->b = Y.b;
+ return;
+ }
+
+
+ // Use Newton's Method to find local minima of sum-of-squares error.
+ float fSteps = (float) (cSteps - 1);
+
+ for(size_t iIteration = 0; iIteration < 8; iIteration++)
+ {
+ // Calculate new steps
+ HDRColorA pSteps[4];
+
+ for(size_t iStep = 0; iStep < cSteps; iStep++)
+ {
+ pSteps[iStep].r = X.r * pC[iStep] + Y.r * pD[iStep];
+ pSteps[iStep].g = X.g * pC[iStep] + Y.g * pD[iStep];
+ pSteps[iStep].b = X.b * pC[iStep] + Y.b * pD[iStep];
+ }
+
+
+ // Calculate color direction
+ Dir.r = Y.r - X.r;
+ Dir.g = Y.g - X.g;
+ Dir.b = Y.b - X.b;
+
+ float fLen = (Dir.r * Dir.r + Dir.g * Dir.g + Dir.b * Dir.b);
+
+ if(fLen < (1.0f / 4096.0f))
+ break;
+
+ float fScale = fSteps / fLen;
+
+ Dir.r *= fScale;
+ Dir.g *= fScale;
+ Dir.b *= fScale;
+
+
+ // Evaluate function, and derivatives
+ float d2X, d2Y;
+ HDRColorA dX, dY;
+ d2X = d2Y = dX.r = dX.g = dX.b = dY.r = dY.g = dY.b = 0.0f;
+
+ for(size_t iPoint = 0; iPoint < NUM_PIXELS_PER_BLOCK; iPoint++)
+ {
+ float fDot = (pPoints[iPoint].r - X.r) * Dir.r +
+ (pPoints[iPoint].g - X.g) * Dir.g +
+ (pPoints[iPoint].b - X.b) * Dir.b;
+
+
+ size_t iStep;
+ if(fDot <= 0.0f)
+ iStep = 0;
+ if(fDot >= fSteps)
+ iStep = cSteps - 1;
+ else
+ iStep = static_cast<size_t>(fDot + 0.5f);
+
+
+ HDRColorA Diff;
+ Diff.r = pSteps[iStep].r - pPoints[iPoint].r;
+ Diff.g = pSteps[iStep].g - pPoints[iPoint].g;
+ Diff.b = pSteps[iStep].b - pPoints[iPoint].b;
+
+#ifdef COLOR_WEIGHTS
+ float fC = pC[iStep] * pPoints[iPoint].a * (1.0f / 8.0f);
+ float fD = pD[iStep] * pPoints[iPoint].a * (1.0f / 8.0f);
+#else
+ float fC = pC[iStep] * (1.0f / 8.0f);
+ float fD = pD[iStep] * (1.0f / 8.0f);
+#endif // COLOR_WEIGHTS
+
+ d2X += fC * pC[iStep];
+ dX.r += fC * Diff.r;
+ dX.g += fC * Diff.g;
+ dX.b += fC * Diff.b;
+
+ d2Y += fD * pD[iStep];
+ dY.r += fD * Diff.r;
+ dY.g += fD * Diff.g;
+ dY.b += fD * Diff.b;
+ }
+
+
+ // Move endpoints
+ if(d2X > 0.0f)
+ {
+ float f = -1.0f / d2X;
+
+ X.r += dX.r * f;
+ X.g += dX.g * f;
+ X.b += dX.b * f;
+ }
+
+ if(d2Y > 0.0f)
+ {
+ float f = -1.0f / d2Y;
+
+ Y.r += dY.r * f;
+ Y.g += dY.g * f;
+ Y.b += dY.b * f;
+ }
+
+ if((dX.r * dX.r < fEpsilon) && (dX.g * dX.g < fEpsilon) && (dX.b * dX.b < fEpsilon) &&
+ (dY.r * dY.r < fEpsilon) && (dY.g * dY.g < fEpsilon) && (dY.b * dY.b < fEpsilon))
+ {
+ break;
+ }
+ }
+
+ pX->r = X.r; pX->g = X.g; pX->b = X.b;
+ pY->r = Y.r; pY->g = Y.g; pY->b = Y.b;
+}
+
+
+//-------------------------------------------------------------------------------------
+inline static void DecodeBC1( _Out_cap_c_(NUM_PIXELS_PER_BLOCK) XMVECTOR *pColor, _In_ const D3DX_BC1 *pBC )
+{
+ assert( pColor && pBC );
+ static_assert( sizeof(D3DX_BC1) == 8, "D3DX_BC1 should be 8 bytes" );
+
+ static XMVECTORF32 s_Scale = { 1.f/31.f, 1.f/63.f, 1.f/31.f, 1.f };
+
+ XMVECTOR clr0 = XMLoadU565( reinterpret_cast<const XMU565*>(&pBC->rgb[0]) );
+ XMVECTOR clr1 = XMLoadU565( reinterpret_cast<const XMU565*>(&pBC->rgb[1]) );
+
+ clr0 = XMVectorMultiply( clr0, s_Scale );
+ clr1 = XMVectorMultiply( clr1, s_Scale );
+
+ clr0 = XMVectorSwizzle( clr0, 2, 1, 0, 3 );
+ clr1 = XMVectorSwizzle( clr1, 2, 1, 0, 3 );
+
+ clr0 = XMVectorSelect( g_XMIdentityR3, clr0, g_XMSelect1110 );
+ clr1 = XMVectorSelect( g_XMIdentityR3, clr1, g_XMSelect1110 );
+
+ XMVECTOR clr2, clr3;
+ if(pBC->rgb[0] <= pBC->rgb[1])
+ {
+ clr2 = XMVectorLerp( clr0, clr1, 0.5f );
+ clr3 = XMVectorZero(); // Alpha of 0
+ }
+ else
+ {
+ clr2 = XMVectorLerp( clr0, clr1, 1.f/3.f );
+ clr3 = XMVectorLerp( clr0, clr1, 2.f/3.f );
+ }
+
+ uint32_t dw = pBC->bitmap;
+
+ for(size_t i = 0; i < NUM_PIXELS_PER_BLOCK; ++i, dw >>= 2)
+ {
+ switch(dw & 3)
+ {
+ case 0: pColor[i] = clr0; break;
+ case 1: pColor[i] = clr1; break;
+ case 2: pColor[i] = clr2; break;
+
+ case 3:
+ default: pColor[i] = clr3; break;
+ }
+ }
+}
+
+
+//-------------------------------------------------------------------------------------
+#pragma warning(disable: 4616 6001 6201)
+
+static void EncodeBC1(_Out_ D3DX_BC1 *pBC, _In_count_c_(NUM_PIXELS_PER_BLOCK) const HDRColorA *pColor,
+ _In_ bool bColorKey, _In_ float alphaRef, _In_ DWORD flags)
+{
+ assert( pBC && pColor );
+ static_assert( sizeof(D3DX_BC1) == 8, "D3DX_BC1 should be 8 bytes" );
+
+ // Determine if we need to colorkey this block
+ size_t uSteps;
+
+ if (bColorKey)
+ {
+ size_t uColorKey = 0;
+
+ for(size_t i = 0; i < NUM_PIXELS_PER_BLOCK; ++i)
+ {
+ if(pColor[i].a < alphaRef)
+ uColorKey++;
+ }
+
+ if(NUM_PIXELS_PER_BLOCK == uColorKey)
+ {
+ pBC->rgb[0] = 0x0000;
+ pBC->rgb[1] = 0xffff;
+ pBC->bitmap = 0xffffffff;
+ return;
+ }
+
+ uSteps = (uColorKey > 0) ? 3 : 4;
+ }
+ else
+ {
+ uSteps = 4;
+ }
+
+ // Quantize block to R56B5, using Floyd Stienberg error diffusion. This
+ // increases the chance that colors will map directly to the quantized
+ // axis endpoints.
+ HDRColorA Color[NUM_PIXELS_PER_BLOCK];
+ HDRColorA Error[NUM_PIXELS_PER_BLOCK];
+
+ if (flags & BC_FLAGS_DITHER_RGB)
+ memset(Error, 0x00, NUM_PIXELS_PER_BLOCK * sizeof(HDRColorA));
+
+ size_t i;
+ for(i = 0; i < NUM_PIXELS_PER_BLOCK; ++i)
+ {
+ HDRColorA Clr;
+ Clr.r = pColor[i].r;
+ Clr.g = pColor[i].g;
+ Clr.b = pColor[i].b;
+
+ if (flags & BC_FLAGS_DITHER_RGB)
+ {
+ Clr.r += Error[i].r;
+ Clr.g += Error[i].g;
+ Clr.b += Error[i].b;
+ }
+
+ Color[i].r = (float) static_cast<int32_t>(Clr.r * 31.0f + 0.5f) * (1.0f / 31.0f);
+ Color[i].g = (float) static_cast<int32_t>(Clr.g * 63.0f + 0.5f) * (1.0f / 63.0f);
+ Color[i].b = (float) static_cast<int32_t>(Clr.b * 31.0f + 0.5f) * (1.0f / 31.0f);
+
+#ifdef COLOR_WEIGHTS
+ Color[i].a = pColor[i].a;
+#else
+ Color[i].a = 1.0f;
+#endif // COLOR_WEIGHTS
+
+ if (flags & BC_FLAGS_DITHER_RGB)
+ {
+ HDRColorA Diff;
+ Diff.r = Color[i].a * (Clr.r - Color[i].r);
+ Diff.g = Color[i].a * (Clr.g - Color[i].g);
+ Diff.b = Color[i].a * (Clr.b - Color[i].b);
+
+ if(3 != (i & 3))
+ {
+ assert( i < 15 );
+ __analysis_assume( i < 15 );
+ Error[i + 1].r += Diff.r * (7.0f / 16.0f);
+ Error[i + 1].g += Diff.g * (7.0f / 16.0f);
+ Error[i + 1].b += Diff.b * (7.0f / 16.0f);
+ }
+
+ if(i < 12)
+ {
+ if(i & 3)
+ {
+ Error[i + 3].r += Diff.r * (3.0f / 16.0f);
+ Error[i + 3].g += Diff.g * (3.0f / 16.0f);
+ Error[i + 3].b += Diff.b * (3.0f / 16.0f);
+ }
+
+ Error[i + 4].r += Diff.r * (5.0f / 16.0f);
+ Error[i + 4].g += Diff.g * (5.0f / 16.0f);
+ Error[i + 4].b += Diff.b * (5.0f / 16.0f);
+
+ if(3 != (i & 3))
+ {
+ assert( i < 11 );
+ __analysis_assume(i < 11 );
+ Error[i + 5].r += Diff.r * (1.0f / 16.0f);
+ Error[i + 5].g += Diff.g * (1.0f / 16.0f);
+ Error[i + 5].b += Diff.b * (1.0f / 16.0f);
+ }
+ }
+ }
+
+ if ( !( flags & BC_FLAGS_UNIFORM ) )
+ {
+ Color[i].r *= g_Luminance.r;
+ Color[i].g *= g_Luminance.g;
+ Color[i].b *= g_Luminance.b;
+ }
+ }
+
+ // Perform 6D root finding function to find two endpoints of color axis.
+ // Then quantize and sort the endpoints depending on mode.
+ HDRColorA ColorA, ColorB, ColorC, ColorD;
+
+ OptimizeRGB(&ColorA, &ColorB, Color, uSteps, flags);
+
+ if ( flags & BC_FLAGS_UNIFORM )
+ {
+ ColorC = ColorA;
+ ColorD = ColorB;
+ }
+ else
+ {
+ ColorC.r = ColorA.r * g_LuminanceInv.r;
+ ColorC.g = ColorA.g * g_LuminanceInv.g;
+ ColorC.b = ColorA.b * g_LuminanceInv.b;
+
+ ColorD.r = ColorB.r * g_LuminanceInv.r;
+ ColorD.g = ColorB.g * g_LuminanceInv.g;
+ ColorD.b = ColorB.b * g_LuminanceInv.b;
+ }
+
+ uint16_t wColorA = Encode565(&ColorC);
+ uint16_t wColorB = Encode565(&ColorD);
+
+ if((uSteps == 4) && (wColorA == wColorB))
+ {
+ pBC->rgb[0] = wColorA;
+ pBC->rgb[1] = wColorB;
+ pBC->bitmap = 0x00000000;
+ return;
+ }
+
+ Decode565(&ColorC, wColorA);
+ Decode565(&ColorD, wColorB);
+
+ if ( flags & BC_FLAGS_UNIFORM )
+ {
+ ColorA = ColorC;
+ ColorB = ColorD;
+ }
+ else
+ {
+ ColorA.r = ColorC.r * g_Luminance.r;
+ ColorA.g = ColorC.g * g_Luminance.g;
+ ColorA.b = ColorC.b * g_Luminance.b;
+
+ ColorB.r = ColorD.r * g_Luminance.r;
+ ColorB.g = ColorD.g * g_Luminance.g;
+ ColorB.b = ColorD.b * g_Luminance.b;
+ }
+
+ // Calculate color steps
+ HDRColorA Step[4];
+
+ if((3 == uSteps) == (wColorA <= wColorB))
+ {
+ pBC->rgb[0] = wColorA;
+ pBC->rgb[1] = wColorB;
+
+ Step[0] = ColorA;
+ Step[1] = ColorB;
+ }
+ else
+ {
+ pBC->rgb[0] = wColorB;
+ pBC->rgb[1] = wColorA;
+
+ Step[0] = ColorB;
+ Step[1] = ColorA;
+ }
+
+ static const size_t pSteps3[] = { 0, 2, 1 };
+ static const size_t pSteps4[] = { 0, 2, 3, 1 };
+ const size_t *pSteps;
+
+ if(3 == uSteps)
+ {
+ pSteps = pSteps3;
+
+ HDRColorALerp(&Step[2], &Step[0], &Step[1], 0.5f);
+ }
+ else
+ {
+ pSteps = pSteps4;
+
+ HDRColorALerp(&Step[2], &Step[0], &Step[1], 1.0f / 3.0f);
+ HDRColorALerp(&Step[3], &Step[0], &Step[1], 2.0f / 3.0f);
+ }
+
+ // Calculate color direction
+ HDRColorA Dir;
+
+ Dir.r = Step[1].r - Step[0].r;
+ Dir.g = Step[1].g - Step[0].g;
+ Dir.b = Step[1].b - Step[0].b;
+
+ float fSteps = (float) (uSteps - 1);
+ float fScale = (wColorA != wColorB) ? (fSteps / (Dir.r * Dir.r + Dir.g * Dir.g + Dir.b * Dir.b)) : 0.0f;
+
+ Dir.r *= fScale;
+ Dir.g *= fScale;
+ Dir.b *= fScale;
+
+ // Encode colors
+ uint32_t dw = 0;
+ if (flags & BC_FLAGS_DITHER_RGB)
+ memset(Error, 0x00, NUM_PIXELS_PER_BLOCK * sizeof(HDRColorA));
+
+ for(i = 0; i < NUM_PIXELS_PER_BLOCK; ++i)
+ {
+ if((3 == uSteps) && (pColor[i].a < alphaRef))
+ {
+ dw = (3 << 30) | (dw >> 2);
+ }
+ else
+ {
+ HDRColorA Clr;
+ if ( flags & BC_FLAGS_UNIFORM )
+ {
+ Clr.r = pColor[i].r;
+ Clr.g = pColor[i].g;
+ Clr.b = pColor[i].b;
+ }
+ else
+ {
+ Clr.r = pColor[i].r * g_Luminance.r;
+ Clr.g = pColor[i].g * g_Luminance.g;
+ Clr.b = pColor[i].b * g_Luminance.b;
+ }
+
+ if (flags & BC_FLAGS_DITHER_RGB)
+ {
+ Clr.r += Error[i].r;
+ Clr.g += Error[i].g;
+ Clr.b += Error[i].b;
+ }
+
+ float fDot = (Clr.r - Step[0].r) * Dir.r + (Clr.g - Step[0].g) * Dir.g + (Clr.b - Step[0].b) * Dir.b;
+ uint32_t iStep;
+
+ if(fDot <= 0.0f)
+ iStep = 0;
+ else if(fDot >= fSteps)
+ iStep = 1;
+ else
+ iStep = static_cast<uint32_t>( pSteps[static_cast<size_t>(fDot + 0.5f)] );
+
+ dw = (iStep << 30) | (dw >> 2);
+
+ if (flags & BC_FLAGS_DITHER_RGB)
+ {
+ HDRColorA Diff;
+ Diff.r = Color[i].a * (Clr.r - Step[iStep].r);
+ Diff.g = Color[i].a * (Clr.g - Step[iStep].g);
+ Diff.b = Color[i].a * (Clr.b - Step[iStep].b);
+
+ if(3 != (i & 3))
+ {
+ Error[i + 1].r += Diff.r * (7.0f / 16.0f);
+ Error[i + 1].g += Diff.g * (7.0f / 16.0f);
+ Error[i + 1].b += Diff.b * (7.0f / 16.0f);
+ }
+
+ if(i < 12)
+ {
+ if(i & 3)
+ {
+ Error[i + 3].r += Diff.r * (3.0f / 16.0f);
+ Error[i + 3].g += Diff.g * (3.0f / 16.0f);
+ Error[i + 3].b += Diff.b * (3.0f / 16.0f);
+ }
+
+ Error[i + 4].r += Diff.r * (5.0f / 16.0f);
+ Error[i + 4].g += Diff.g * (5.0f / 16.0f);
+ Error[i + 4].b += Diff.b * (5.0f / 16.0f);
+
+ if(3 != (i & 3))
+ {
+ Error[i + 5].r += Diff.r * (1.0f / 16.0f);
+ Error[i + 5].g += Diff.g * (1.0f / 16.0f);
+ Error[i + 5].b += Diff.b * (1.0f / 16.0f);
+ }
+ }
+ }
+ }
+ }
+
+ pBC->bitmap = dw;
+}
+
+//-------------------------------------------------------------------------------------
+#ifdef COLOR_WEIGHTS
+static void EncodeSolidBC1(_Out_ D3DX_BC1 *pBC, _In_count_c_(NUM_PIXELS_PER_BLOCK) const HDRColorA *pColor)
+{
+#ifdef COLOR_AVG_0WEIGHTS
+ // Compute avg color
+ HDRColorA Color;
+ Color.r = pColor[0].r;
+ Color.g = pColor[0].g;
+ Color.b = pColor[0].b;
+
+ for(size_t i = 1; i < NUM_PIXELS_PER_BLOCK; ++i)
+ {
+ Color.r += pColor[i].r;
+ Color.g += pColor[i].g;
+ Color.b += pColor[i].b;
+ }
+
+ Color.r *= 1.0f / 16.0f;
+ Color.g *= 1.0f / 16.0f;
+ Color.b *= 1.0f / 16.0f;
+
+ uint16_t wColor = Encode565(&Color);
+#else
+ uint16_t wColor = 0x0000;
+#endif // COLOR_AVG_0WEIGHTS
+
+ // Encode solid block
+ pBC->rgb[0] = wColor;
+ pBC->rgb[1] = wColor;
+ pBC->bitmap = 0x00000000;
+}
+#endif // COLOR_WEIGHTS
+
+
+//=====================================================================================
+// Entry points
+//=====================================================================================
+
+//-------------------------------------------------------------------------------------
+// BC1 Compression
+//-------------------------------------------------------------------------------------
+void D3DXDecodeBC1(XMVECTOR *pColor, const uint8_t *pBC)
+{
+ const D3DX_BC1 *pBC1 = reinterpret_cast<const D3DX_BC1 *>(pBC);
+ DecodeBC1( pColor, pBC1 );
+}
+
+void D3DXEncodeBC1(uint8_t *pBC, const XMVECTOR *pColor, float alphaRef, DWORD flags)
+{
+ assert( pBC && pColor );
+
+ HDRColorA Color[NUM_PIXELS_PER_BLOCK];
+
+ if (flags & BC_FLAGS_DITHER_A)
+ {
+ float fError[NUM_PIXELS_PER_BLOCK];
+ memset(fError, 0x00, NUM_PIXELS_PER_BLOCK * sizeof(float));
+
+ for(size_t i = 0; i < NUM_PIXELS_PER_BLOCK; ++i)
+ {
+ HDRColorA clr;
+ XMStoreFloat4( reinterpret_cast<XMFLOAT4*>( &clr ), pColor[i] );
+
+ float fAlph = clr.a + fError[i];
+
+ Color[i].r = clr.r;
+ Color[i].g = clr.g;
+ Color[i].b = clr.b;
+ Color[i].a = (float) static_cast<int32_t>(clr.a + fError[i] + 0.5f);
+
+ float fDiff = fAlph - Color[i].a;
+
+ if(3 != (i & 3))
+ {
+ assert( i < 15 );
+ __analysis_assume( i < 15 );
+ fError[i + 1] += fDiff * (7.0f / 16.0f);
+ }
+
+ if(i < 12)
+ {
+ if(i & 3)
+ fError[i + 3] += fDiff * (3.0f / 16.0f);
+
+ fError[i + 4] += fDiff * (5.0f / 16.0f);
+
+ if(3 != (i & 3))
+ {
+ assert( i < 11 );
+ __analysis_assume( i < 11 );
+ fError[i + 5] += fDiff * (1.0f / 16.0f);
+ }
+ }
+ }
+ }
+ else
+ {
+ for(size_t i = 0; i < NUM_PIXELS_PER_BLOCK; ++i)
+ {
+ XMStoreFloat4( reinterpret_cast<XMFLOAT4*>( &Color[i] ), pColor[i] );
+ }
+ }
+
+ D3DX_BC1 *pBC1 = reinterpret_cast<D3DX_BC1 *>(pBC);
+ EncodeBC1(pBC1, Color, true, alphaRef, flags);
+}
+
+
+//-------------------------------------------------------------------------------------
+// BC2 Compression
+//-------------------------------------------------------------------------------------
+void D3DXDecodeBC2(XMVECTOR *pColor, const uint8_t *pBC)
+{
+ assert( pColor && pBC );
+ static_assert( sizeof(D3DX_BC2) == 16, "D3DX_BC2 should be 16 bytes" );
+
+ const D3DX_BC2 *pBC2 = reinterpret_cast<const D3DX_BC2 *>(pBC);
+
+ // RGB part
+ DecodeBC1(pColor, &pBC2->bc1);
+
+ // 4-bit alpha part
+ DWORD dw = pBC2->bitmap[0];
+
+ for(size_t i = 0; i < 8; ++i, dw >>= 4)
+ pColor[i] = XMVectorSetW( pColor[i], (float) (dw & 0xf) * (1.0f / 15.0f) );
+
+ dw = pBC2->bitmap[1];
+
+ for(size_t i = 8; i < NUM_PIXELS_PER_BLOCK; ++i, dw >>= 4)
+ pColor[i] = XMVectorSetW( pColor[i], (float) (dw & 0xf) * (1.0f / 15.0f) );
+}
+
+void D3DXEncodeBC2(uint8_t *pBC, const XMVECTOR *pColor, DWORD flags)
+{
+ assert( pBC && pColor );
+ static_assert( sizeof(D3DX_BC2) == 16, "D3DX_BC2 should be 16 bytes" );
+
+ HDRColorA Color[NUM_PIXELS_PER_BLOCK];
+ for(size_t i = 0; i < NUM_PIXELS_PER_BLOCK; ++i)
+ {
+ XMStoreFloat4( reinterpret_cast<XMFLOAT4*>( &Color[i] ), pColor[i] );
+ }
+
+ D3DX_BC2 *pBC2 = reinterpret_cast<D3DX_BC2 *>(pBC);
+
+ // 4-bit alpha part. Dithered using Floyd Stienberg error diffusion.
+ pBC2->bitmap[0] = 0;
+ pBC2->bitmap[1] = 0;
+
+ float fError[NUM_PIXELS_PER_BLOCK];
+ if (flags & BC_FLAGS_DITHER_A)
+ memset(fError, 0x00, NUM_PIXELS_PER_BLOCK * sizeof(float));
+
+ for(size_t i = 0; i < NUM_PIXELS_PER_BLOCK; ++i)
+ {
+ float fAlph = Color[i].a;
+ if (flags & BC_FLAGS_DITHER_A)
+ fAlph += fError[i];
+
+ uint32_t u = (uint32_t) static_cast<int32_t>(fAlph * 15.0f + 0.5f);
+
+ pBC2->bitmap[i >> 3] >>= 4;
+ pBC2->bitmap[i >> 3] |= (u << 28);
+
+ if (flags & BC_FLAGS_DITHER_A)
+ {
+ float fDiff = fAlph - (float) u * (1.0f / 15.0f);
+
+ if(3 != (i & 3))
+ {
+ assert( i < 15 );
+ __analysis_assume( i < 15 );
+ fError[i + 1] += fDiff * (7.0f / 16.0f);
+ }
+
+ if(i < 12)
+ {
+ if(i & 3)
+ fError[i + 3] += fDiff * (3.0f / 16.0f);
+
+ fError[i + 4] += fDiff * (5.0f / 16.0f);
+
+ if(3 != (i & 3))
+ {
+ assert( i < 11 );
+ __analysis_assume( i < 11 );
+ fError[i + 5] += fDiff * (1.0f / 16.0f);
+ }
+ }
+ }
+ }
+
+ // RGB part
+#ifdef COLOR_WEIGHTS
+ if(!pBC2->bitmap[0] && !pBC2->bitmap[1])
+ {
+ EncodeSolidBC1(pBC2->dxt1, Color);
+ return;
+ }
+#endif // COLOR_WEIGHTS
+
+ EncodeBC1(&pBC2->bc1, Color, false, 0.f, flags);
+}
+
+
+//-------------------------------------------------------------------------------------
+// BC3 Compression
+//-------------------------------------------------------------------------------------
+void D3DXDecodeBC3(XMVECTOR *pColor, const uint8_t *pBC)
+{
+ assert( pColor && pBC );
+ static_assert( sizeof(D3DX_BC3) == 16, "D3DX_BC3 should be 16 bytes" );
+
+ const D3DX_BC3 *pBC3 = reinterpret_cast<const D3DX_BC3 *>(pBC);
+
+ // RGB part
+ DecodeBC1(pColor, &pBC3->bc1);
+
+ // Adaptive 3-bit alpha part
+ float fAlpha[8];
+
+ fAlpha[0] = ((float) pBC3->alpha[0]) * (1.0f / 255.0f);
+ fAlpha[1] = ((float) pBC3->alpha[1]) * (1.0f / 255.0f);
+
+ if(pBC3->alpha[0] > pBC3->alpha[1])
+ {
+ for(size_t i = 1; i < 7; ++i)
+ fAlpha[i + 1] = (fAlpha[0] * (7 - i) + fAlpha[1] * i) * (1.0f / 7.0f);
+ }
+ else
+ {
+ for(size_t i = 1; i < 5; ++i)
+ fAlpha[i + 1] = (fAlpha[0] * (5 - i) + fAlpha[1] * i) * (1.0f / 5.0f);
+
+ fAlpha[6] = 0.0f;
+ fAlpha[7] = 1.0f;
+ }
+
+ DWORD dw = pBC3->bitmap[0] | (pBC3->bitmap[1] << 8) | (pBC3->bitmap[2] << 16);
+
+ for(size_t i = 0; i < 8; ++i, dw >>= 3)
+ pColor[i] = XMVectorSetW( pColor[i], fAlpha[dw & 0x7] );
+
+ dw = pBC3->bitmap[3] | (pBC3->bitmap[4] << 8) | (pBC3->bitmap[5] << 16);
+
+ for(size_t i = 8; i < NUM_PIXELS_PER_BLOCK; ++i, dw >>= 3)
+ pColor[i] = XMVectorSetW( pColor[i], fAlpha[dw & 0x7] );
+}
+
+void D3DXEncodeBC3(uint8_t *pBC, const XMVECTOR *pColor, DWORD flags)
+{
+ assert( pBC && pColor );
+ static_assert( sizeof(D3DX_BC3) == 16, "D3DX_BC3 should be 16 bytes" );
+
+ HDRColorA Color[NUM_PIXELS_PER_BLOCK];
+ for(size_t i = 0; i < NUM_PIXELS_PER_BLOCK; ++i)
+ {
+ XMStoreFloat4( reinterpret_cast<XMFLOAT4*>( &Color[i] ), pColor[i] );
+ }
+
+ D3DX_BC3 *pBC3 = reinterpret_cast<D3DX_BC3 *>(pBC);
+
+ // Quantize block to A8, using Floyd Stienberg error diffusion. This
+ // increases the chance that colors will map directly to the quantized
+ // axis endpoints.
+ float fAlpha[NUM_PIXELS_PER_BLOCK];
+ float fError[NUM_PIXELS_PER_BLOCK];
+
+ float fMinAlpha = Color[0].a;
+ float fMaxAlpha = Color[0].a;
+
+ if (flags & BC_FLAGS_DITHER_A)
+ memset(fError, 0x00, NUM_PIXELS_PER_BLOCK * sizeof(float));
+
+ for(size_t i = 0; i < NUM_PIXELS_PER_BLOCK; ++i)
+ {
+ float fAlph = Color[i].a;
+ if (flags & BC_FLAGS_DITHER_A)
+ fAlph += fError[i];
+
+ fAlpha[i] = static_cast<int32_t>(fAlph * 255.0f + 0.5f) * (1.0f / 255.0f);
+
+ if(fAlpha[i] < fMinAlpha)
+ fMinAlpha = fAlpha[i];
+ else if(fAlpha[i] > fMaxAlpha)
+ fMaxAlpha = fAlpha[i];
+
+ if (flags & BC_FLAGS_DITHER_A)
+ {
+ float fDiff = fAlph - fAlpha[i];
+
+ if(3 != (i & 3))
+ {
+ assert( i < 15 );
+ __analysis_assume( i < 15 );
+ fError[i + 1] += fDiff * (7.0f / 16.0f);
+ }
+
+ if(i < 12)
+ {
+ if(i & 3)
+ fError[i + 3] += fDiff * (3.0f / 16.0f);
+
+ fError[i + 4] += fDiff * (5.0f / 16.0f);
+
+ if(3 != (i & 3))
+ {
+ assert( i < 11 );
+ __analysis_assume( i < 11 );
+ fError[i + 5] += fDiff * (1.0f / 16.0f);
+ }
+ }
+ }
+ }
+
+#ifdef COLOR_WEIGHTS
+ if(0.0f == fMaxAlpha)
+ {
+ EncodeSolidBC1(&pBC3->dxt1, Color);
+ pBC3->alpha[0] = 0x00;
+ pBC3->alpha[1] = 0x00;
+ memset(pBC3->bitmap, 0x00, 6);
+ }
+#endif
+
+ // RGB part
+ EncodeBC1(&pBC3->bc1, Color, false, 0.f, flags);
+
+ // Alpha part
+ if(1.0f == fMinAlpha)
+ {
+ pBC3->alpha[0] = 0xff;
+ pBC3->alpha[1] = 0xff;
+ memset(pBC3->bitmap, 0x00, 6);
+ return;
+ }
+
+ // Optimize and Quantize Min and Max values
+ size_t uSteps = ((0.0f == fMinAlpha) || (1.0f == fMaxAlpha)) ? 6 : 8;
+
+ float fAlphaA, fAlphaB;
+ OptimizeAlpha<false>(&fAlphaA, &fAlphaB, fAlpha, uSteps);
+
+ uint8_t bAlphaA = (uint8_t) static_cast<int32_t>(fAlphaA * 255.0f + 0.5f);
+ uint8_t bAlphaB = (uint8_t) static_cast<int32_t>(fAlphaB * 255.0f + 0.5f);
+
+ fAlphaA = (float) bAlphaA * (1.0f / 255.0f);
+ fAlphaB = (float) bAlphaB * (1.0f / 255.0f);
+
+ // Setup block
+ if((8 == uSteps) && (bAlphaA == bAlphaB))
+ {
+ pBC3->alpha[0] = bAlphaA;
+ pBC3->alpha[1] = bAlphaB;
+ memset(pBC3->bitmap, 0x00, 6);
+ return;
+ }
+
+ static const size_t pSteps6[] = { 0, 2, 3, 4, 5, 1 };
+ static const size_t pSteps8[] = { 0, 2, 3, 4, 5, 6, 7, 1 };
+
+ const size_t *pSteps;
+ float fStep[8];
+
+ if(6 == uSteps)
+ {
+ pBC3->alpha[0] = bAlphaA;
+ pBC3->alpha[1] = bAlphaB;
+
+ fStep[0] = fAlphaA;
+ fStep[1] = fAlphaB;
+
+ for(size_t i = 1; i < 5; ++i)
+ fStep[i + 1] = (fStep[0] * (5 - i) + fStep[1] * i) * (1.0f / 5.0f);
+
+ fStep[6] = 0.0f;
+ fStep[7] = 1.0f;
+
+ pSteps = pSteps6;
+ }
+ else
+ {
+ pBC3->alpha[0] = bAlphaB;
+ pBC3->alpha[1] = bAlphaA;
+
+ fStep[0] = fAlphaB;
+ fStep[1] = fAlphaA;
+
+ for(size_t i = 1; i < 7; ++i)
+ fStep[i + 1] = (fStep[0] * (7 - i) + fStep[1] * i) * (1.0f / 7.0f);
+
+ pSteps = pSteps8;
+ }
+
+ // Encode alpha bitmap
+ float fSteps = (float) (uSteps - 1);
+ float fScale = (fStep[0] != fStep[1]) ? (fSteps / (fStep[1] - fStep[0])) : 0.0f;
+
+ if (flags & BC_FLAGS_DITHER_A)
+ memset(fError, 0x00, NUM_PIXELS_PER_BLOCK * sizeof(float));
+
+ for(size_t iSet = 0; iSet < 2; iSet++)
+ {
+ uint32_t dw = 0;
+
+ size_t iMin = iSet * 8;
+ size_t iLim = iMin + 8;
+
+ for(size_t i = iMin; i < iLim; ++i)
+ {
+ float fAlph = Color[i].a;
+ if (flags & BC_FLAGS_DITHER_A)
+ fAlph += fError[i];
+ float fDot = (fAlph - fStep[0]) * fScale;
+
+ uint32_t iStep;
+ if(fDot <= 0.0f)
+ iStep = ((6 == uSteps) && (fAlph <= fStep[0] * 0.5f)) ? 6 : 0;
+ else if(fDot >= fSteps)
+ iStep = ((6 == uSteps) && (fAlph >= (fStep[1] + 1.0f) * 0.5f)) ? 7 : 1;
+ else
+ iStep = static_cast<uint32_t>( pSteps[static_cast<size_t>(fDot + 0.5f)] );
+
+ dw = (iStep << 21) | (dw >> 3);
+
+ if (flags & BC_FLAGS_DITHER_A)
+ {
+ float fDiff = (fAlph - fStep[iStep]);
+
+ if(3 != (i & 3))
+ fError[i + 1] += fDiff * (7.0f / 16.0f);
+
+ if(i < 12)
+ {
+ if(i & 3)
+ fError[i + 3] += fDiff * (3.0f / 16.0f);
+
+ fError[i + 4] += fDiff * (5.0f / 16.0f);
+
+ if(3 != (i & 3))
+ fError[i + 5] += fDiff * (1.0f / 16.0f);
+ }
+ }
+ }
+
+ pBC3->bitmap[0 + iSet * 3] = ((uint8_t *) &dw)[0];
+ pBC3->bitmap[1 + iSet * 3] = ((uint8_t *) &dw)[1];
+ pBC3->bitmap[2 + iSet * 3] = ((uint8_t *) &dw)[2];
+ }
+}
+
+} // namespace
\ No newline at end of file
projects / apitrace / blobdiff