1 files changed, 261 insertions, 0 deletions
diff --git a/thirdparty/etc2comp/EtcBlock4x4Encoding.cpp b/thirdparty/etc2comp/EtcBlock4x4Encoding.cpp
new file mode 100644
index 0000000000..7a9e68c4cf
--- /dev/null
+++ b/thirdparty/etc2comp/EtcBlock4x4Encoding.cpp
@@ -0,0 +1,261 @@
+/*
+ * Copyright 2015 The Etc2Comp Authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *  http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/*
+EtcBlock4x4Encoding.cpp
+
+Block4x4Encoding is the abstract base class for the different encoders.  Each encoder targets a 
+particular file format (e.g. ETC1, RGB8, RGBA8, R11)
+
+*/
+
+#include "EtcConfig.h"
+#include "EtcBlock4x4Encoding.h"
+
+#include "EtcBlock4x4EncodingBits.h"
+#include "EtcBlock4x4.h"
+
+#include <stdio.h>
+#include <string.h>
+#include <assert.h>
+
+namespace Etc
+{
+	// ----------------------------------------------------------------------------------------------------
+	//
+	const float Block4x4Encoding::LUMA_WEIGHT = 3.0f;
+	const float Block4x4Encoding::CHROMA_BLUE_WEIGHT = 0.5f;
+
+	// ----------------------------------------------------------------------------------------------------
+	//
+	Block4x4Encoding::Block4x4Encoding(void)
+	{
+
+		m_pblockParent = nullptr;
+
+		m_pafrgbaSource = nullptr;
+
+		m_boolBorderPixels = false;
+
+		m_fError = -1.0f;
+
+		m_mode = MODE_UNKNOWN;
+
+		m_uiEncodingIterations = 0;
+		m_boolDone = false;
+
+		for (unsigned int uiPixel = 0; uiPixel < PIXELS; uiPixel++)
+		{
+			m_afrgbaDecodedColors[uiPixel] = ColorFloatRGBA(-1.0f, -1.0f, -1.0f, -1.0f);
+			m_afDecodedAlphas[uiPixel] = -1.0f;
+		}
+
+	}
+
+	// ----------------------------------------------------------------------------------------------------
+	// initialize the generic encoding for a 4x4 block
+	// a_pblockParent points to the block associated with this encoding
+	// a_errormetric is used to choose the best encoding
+	// init the decoded pixels to -1 to mark them as undefined
+	// init the error to -1 to mark it as undefined
+	//
+	void Block4x4Encoding::Init(Block4x4 *a_pblockParent,
+								ColorFloatRGBA *a_pafrgbaSource,
+								ErrorMetric a_errormetric)
+	{
+
+		m_pblockParent = a_pblockParent;
+
+		m_pafrgbaSource = a_pafrgbaSource;
+
+		m_boolBorderPixels = m_pblockParent->HasBorderPixels();
+
+		m_fError = -1.0f;
+
+		m_uiEncodingIterations = 0;
+
+		m_errormetric = a_errormetric;
+
+		for (unsigned int uiPixel = 0; uiPixel < PIXELS; uiPixel++)
+		{
+			m_afrgbaDecodedColors[uiPixel] = ColorFloatRGBA(-1.0f, -1.0f, -1.0f, -1.0f);
+			m_afDecodedAlphas[uiPixel] = -1.0f;
+		}
+
+	}
+
+	// ----------------------------------------------------------------------------------------------------
+	// calculate the error for the block by summing the pixel errors
+	//
+	void Block4x4Encoding::CalcBlockError(void)
+	{
+		m_fError = 0.0f;
+
+		for (unsigned int uiPixel = 0; uiPixel < PIXELS; uiPixel++)
+		{
+			m_fError += CalcPixelError(m_afrgbaDecodedColors[uiPixel], m_afDecodedAlphas[uiPixel],
+										m_pafrgbaSource[uiPixel]);
+		}
+		
+	}
+
+	// ----------------------------------------------------------------------------------------------------
+	// calculate the error between the source pixel and the decoded pixel
+	// the error amount is base on the error metric
+	//
+	float Block4x4Encoding::CalcPixelError(ColorFloatRGBA a_frgbaDecodedColor, float a_fDecodedAlpha,
+											ColorFloatRGBA a_frgbaSourcePixel)
+	{
+
+		// if a border pixel
+		if (isnan(a_frgbaSourcePixel.fA))
+		{
+			return 0.0f;
+		}
+
+		if (m_errormetric == ErrorMetric::RGBA)
+		{
+			assert(a_fDecodedAlpha >= 0.0f);
+
+			float fDRed = (a_fDecodedAlpha * a_frgbaDecodedColor.fR) -
+							(a_frgbaSourcePixel.fA * a_frgbaSourcePixel.fR);
+			float fDGreen = (a_fDecodedAlpha * a_frgbaDecodedColor.fG) -
+							(a_frgbaSourcePixel.fA * a_frgbaSourcePixel.fG);
+			float fDBlue = (a_fDecodedAlpha * a_frgbaDecodedColor.fB) -
+							(a_frgbaSourcePixel.fA * a_frgbaSourcePixel.fB);
+
+			float fDAlpha = a_fDecodedAlpha - a_frgbaSourcePixel.fA;
+
+			return fDRed*fDRed + fDGreen*fDGreen + fDBlue*fDBlue + fDAlpha*fDAlpha;
+		}
+		else if (m_errormetric == ErrorMetric::RGBX)
+		{
+			assert(a_fDecodedAlpha >= 0.0f);
+
+			float fDRed = a_frgbaDecodedColor.fR - a_frgbaSourcePixel.fR;
+			float fDGreen = a_frgbaDecodedColor.fG - a_frgbaSourcePixel.fG;
+			float fDBlue = a_frgbaDecodedColor.fB - a_frgbaSourcePixel.fB;
+			float fDAlpha = a_fDecodedAlpha - a_frgbaSourcePixel.fA;
+
+			return fDRed*fDRed + fDGreen*fDGreen + fDBlue*fDBlue + fDAlpha*fDAlpha;
+		}
+		else if (m_errormetric == ErrorMetric::REC709)
+		{
+			assert(a_fDecodedAlpha >= 0.0f);
+
+			float fLuma1 = a_frgbaSourcePixel.fR*0.2126f + a_frgbaSourcePixel.fG*0.7152f + a_frgbaSourcePixel.fB*0.0722f;
+			float fChromaR1 = 0.5f * ((a_frgbaSourcePixel.fR - fLuma1) * (1.0f / (1.0f - 0.2126f)));
+			float fChromaB1 = 0.5f * ((a_frgbaSourcePixel.fB - fLuma1) * (1.0f / (1.0f - 0.0722f)));
+
+			float fLuma2 = a_frgbaDecodedColor.fR*0.2126f +
+							a_frgbaDecodedColor.fG*0.7152f +
+							a_frgbaDecodedColor.fB*0.0722f;
+			float fChromaR2 = 0.5f * ((a_frgbaDecodedColor.fR - fLuma2) * (1.0f / (1.0f - 0.2126f)));
+			float fChromaB2 = 0.5f * ((a_frgbaDecodedColor.fB - fLuma2) * (1.0f / (1.0f - 0.0722f)));
+
+			float fDeltaL = a_frgbaSourcePixel.fA * fLuma1 - a_fDecodedAlpha * fLuma2;
+			float fDeltaCr = a_frgbaSourcePixel.fA * fChromaR1 - a_fDecodedAlpha * fChromaR2;
+			float fDeltaCb = a_frgbaSourcePixel.fA * fChromaB1 - a_fDecodedAlpha * fChromaB2;
+
+			float fDAlpha = a_fDecodedAlpha - a_frgbaSourcePixel.fA;
+
+			// Favor Luma accuracy over Chroma, and Red over Blue 
+			return LUMA_WEIGHT*fDeltaL*fDeltaL +
+					fDeltaCr*fDeltaCr +
+					CHROMA_BLUE_WEIGHT*fDeltaCb*fDeltaCb +
+					fDAlpha*fDAlpha;
+	#if 0
+			float fDRed = a_frgbaDecodedPixel.fR - a_frgbaSourcePixel.fR;
+			float fDGreen = a_frgbaDecodedPixel.fG - a_frgbaSourcePixel.fG;
+			float fDBlue = a_frgbaDecodedPixel.fB - a_frgbaSourcePixel.fB;
+			return 2.0f * 3.0f * fDeltaL * fDeltaL + fDRed*fDRed + fDGreen*fDGreen + fDBlue*fDBlue;
+#endif
+		}
+		else if (m_errormetric == ErrorMetric::NORMALXYZ)
+		{
+			float fDecodedX = 2.0f * a_frgbaDecodedColor.fR - 1.0f;
+			float fDecodedY = 2.0f * a_frgbaDecodedColor.fG - 1.0f;
+			float fDecodedZ = 2.0f * a_frgbaDecodedColor.fB - 1.0f;
+
+			float fDecodedLength = sqrtf(fDecodedX*fDecodedX + fDecodedY*fDecodedY + fDecodedZ*fDecodedZ);
+
+			if (fDecodedLength < 0.5f)
+			{
+				return 1.0f;
+			}
+			else if (fDecodedLength == 0.0f)
+			{
+				fDecodedX = 1.0f;
+				fDecodedY = 0.0f;
+				fDecodedZ = 0.0f;
+			}
+			else
+			{
+				fDecodedX /= fDecodedLength;
+				fDecodedY /= fDecodedLength;
+				fDecodedZ /= fDecodedLength;
+			}
+
+			float fSourceX = 2.0f * a_frgbaSourcePixel.fR - 1.0f;
+			float fSourceY = 2.0f * a_frgbaSourcePixel.fG - 1.0f;
+			float fSourceZ = 2.0f * a_frgbaSourcePixel.fB - 1.0f;
+
+			float fSourceLength = sqrtf(fSourceX*fSourceX + fSourceY*fSourceY + fSourceZ*fSourceZ);
+
+			if (fSourceLength == 0.0f)
+			{
+				fSourceX = 1.0f;
+				fSourceY = 0.0f;
+				fSourceZ = 0.0f;
+			}
+			else
+			{
+				fSourceX /= fSourceLength;
+				fSourceY /= fSourceLength;
+				fSourceZ /= fSourceLength;
+			}
+
+			float fDotProduct = fSourceX*fDecodedX + fSourceY*fDecodedY + fSourceZ*fDecodedZ;
+			float fNormalizedDotProduct = 1.0f - 0.5f * (fDotProduct + 1.0f);
+			float fDotProductError = fNormalizedDotProduct * fNormalizedDotProduct;
+			
+			float fLength2 = fDecodedX*fDecodedX + fDecodedY*fDecodedY + fDecodedZ*fDecodedZ;
+			float fLength2Error = fabsf(1.0f - fLength2);
+
+			float fDeltaW = a_frgbaDecodedColor.fA - a_frgbaSourcePixel.fA;
+			float fErrorW = fDeltaW * fDeltaW;
+
+			return fDotProductError + fLength2Error + fErrorW;
+		}
+		else // ErrorMetric::NUMERIC
+		{
+			assert(a_fDecodedAlpha >= 0.0f);
+
+			float fDX = a_frgbaDecodedColor.fR - a_frgbaSourcePixel.fR;
+			float fDY = a_frgbaDecodedColor.fG - a_frgbaSourcePixel.fG;
+			float fDZ = a_frgbaDecodedColor.fB - a_frgbaSourcePixel.fB;
+			float fDW = a_frgbaDecodedColor.fA - a_frgbaSourcePixel.fA;
+
+			return fDX*fDX + fDY*fDY + fDZ*fDZ + fDW*fDW;
+		}
+
+	}
+
+	// ----------------------------------------------------------------------------------------------------
+	//
+
+} // namespace Etc
+