commit 049a187a80a1b9f873593bf2af1b5349d6575e18
author Alexis Hetu <sugoi@google.com> Mon Apr 25 16:59:58 2016 -0400
committer Alexis Hétu <sugoi@google.com> Thu Apr 28 15:41:15 2016 +0000
tree 1834e5caffd6e1b96ce8db2d49f310514d5d991a
parent 5c26c290d8aea3fdad52dc93299f5ddc89d5bc47

SRGB implementation

The SRGB conversion code was already available, but wasn't used
specifically for the SRGB type framebuffers. Also, the SRGB
conversion should always be applied after blending.

According to the GLES 3.0 spec, section 4.1.8 - sRGB Conversion:
"the R, G, and B values after blending are converted
 into the non-linear sRGB color space by computing."

All related dEQP tests pass.

Change-Id: I9342d2f74aa650f28835a951bdfa8bd371bc6924
Reviewed-on: https://swiftshader-review.googlesource.com/5189
Tested-by: Alexis Hétu <sugoi@google.com>
Reviewed-by: Nicolas Capens <capn@google.com>
Tested-by: Nicolas Capens <capn@google.com>

src/Shader/PixelRoutine.cpp

diff --git a/src/Shader/PixelRoutine.cpp b/src/Shader/PixelRoutine.cpp
index ca38074..a1a752c 100644
--- a/src/Shader/PixelRoutine.cpp
+++ b/src/Shader/PixelRoutine.cpp
@@ -996,6 +996,11 @@
 		}
 	}
 
+	bool PixelRoutine::isSRGB(int index) const
+	{
+		return state.targetFormat[index] == FORMAT_SRGB8_A8 || state.targetFormat[index] == FORMAT_SRGB8_X8;
+	}
+
 	void PixelRoutine::readPixel(int index, Pointer<Byte> &cBuffer, Int &x, Vector4s &pixel)
 	{
 		Short4 c01;
@@ -1035,6 +1040,7 @@
 			pixel.w = UnpackHigh(As<Byte8>(pixel.w), As<Byte8>(pixel.w));
 			break;
 		case FORMAT_A8B8G8R8:
+		case FORMAT_SRGB8_A8:
 			buffer = cBuffer + 4 * x;
 			c01 = *Pointer<Short4>(buffer);
 			buffer += *Pointer<Int>(data + OFFSET(DrawData, colorPitchB[index]));
@@ -1082,6 +1088,7 @@
 			pixel.w = Short4(0xFFFFu);
 			break;
 		case FORMAT_X8B8G8R8:
+		case FORMAT_SRGB8_X8:
 			buffer = cBuffer + 4 * x;
 			c01 = *Pointer<Short4>(buffer);
 			buffer += *Pointer<Int>(data + OFFSET(DrawData, colorPitchB[index]));
@@ -1141,7 +1148,7 @@
 			ASSERT(false);
 		}
 
-		if(postBlendSRGB && state.writeSRGB)
+		if((postBlendSRGB && state.writeSRGB) || isSRGB(index))
 		{
 			sRGBtoLinear16_12_16(pixel);
 		}
@@ -1363,7 +1370,7 @@
 
 	void PixelRoutine::writeColor(int index, Pointer<Byte> &cBuffer, Int &x, Vector4s &current, Int &sMask, Int &zMask, Int &cMask)
 	{
-		if(postBlendSRGB && state.writeSRGB)
+		if((postBlendSRGB && state.writeSRGB) || isSRGB(index))
 		{
 			linearToSRGB16_12_16(current);
 		}
@@ -1383,6 +1390,8 @@
 			case FORMAT_X8B8G8R8:
 			case FORMAT_A8R8G8B8:
 			case FORMAT_A8B8G8R8:
+			case FORMAT_SRGB8_X8:
+			case FORMAT_SRGB8_A8:
 				current.x = current.x - As<Short4>(As<UShort4>(current.x) >> 8) + Short4(0x0080, 0x0080, 0x0080, 0x0080);
 				current.y = current.y - As<Short4>(As<UShort4>(current.y) >> 8) + Short4(0x0080, 0x0080, 0x0080, 0x0080);
 				current.z = current.z - As<Short4>(As<UShort4>(current.z) >> 8) + Short4(0x0080, 0x0080, 0x0080, 0x0080);
@@ -1465,7 +1474,9 @@
 			break;
 		case FORMAT_X8B8G8R8:
 		case FORMAT_A8B8G8R8:
-			if(state.targetFormat[index] == FORMAT_X8B8G8R8 || rgbaWriteMask == 0x7)
+		case FORMAT_SRGB8_X8:
+		case FORMAT_SRGB8_A8:
+			if(state.targetFormat[index] == FORMAT_X8B8G8R8 || state.targetFormat[index] == FORMAT_SRGB8_X8 || rgbaWriteMask == 0x7)
 			{
 				current.x = As<Short4>(As<UShort4>(current.x) >> 8);
 				current.y = As<Short4>(As<UShort4>(current.y) >> 8);
@@ -1655,13 +1666,17 @@
 			break;
 		case FORMAT_A8B8G8R8:
 		case FORMAT_X8B8G8R8:   // FIXME: Don't touch alpha?
+		case FORMAT_SRGB8_X8:
+		case FORMAT_SRGB8_A8:
 			{
 				Pointer<Byte> buffer = cBuffer + x * 4;
 				Short4 value = *Pointer<Short4>(buffer);
 
-				if((state.targetFormat[index] == FORMAT_A8B8G8R8 && rgbaWriteMask != 0x0000000F) ||
-				   ((state.targetFormat[index] == FORMAT_X8B8G8R8 && rgbaWriteMask != 0x00000007) &&
-					(state.targetFormat[index] == FORMAT_X8B8G8R8 && rgbaWriteMask != 0x0000000F)))   // FIXME: Need for masking when XBGR && Fh?
+				bool masked = (((state.targetFormat[index] == FORMAT_A8B8G8R8 || state.targetFormat[index] == FORMAT_SRGB8_A8) && rgbaWriteMask != 0x0000000F) ||
+				              (((state.targetFormat[index] == FORMAT_X8B8G8R8 || state.targetFormat[index] == FORMAT_SRGB8_X8) && rgbaWriteMask != 0x00000007) &&
+				               ((state.targetFormat[index] == FORMAT_X8B8G8R8 || state.targetFormat[index] == FORMAT_SRGB8_X8) && rgbaWriteMask != 0x0000000F))); // FIXME: Need for masking when XBGR && Fh?
+
+				if(masked)
 				{
 					Short4 masked = value;
 					c01 &= *Pointer<Short4>(constants + OFFSET(Constants,maskB4Q[rgbaWriteMask][0]));
@@ -1677,9 +1692,7 @@
 				buffer += *Pointer<Int>(data + OFFSET(DrawData,colorPitchB[index]));
 				value = *Pointer<Short4>(buffer);
 
-				if((state.targetFormat[index] == FORMAT_A8B8G8R8 && rgbaWriteMask != 0x0000000F) ||
-				   ((state.targetFormat[index] == FORMAT_X8B8G8R8 && rgbaWriteMask != 0x00000007) &&
-					(state.targetFormat[index] == FORMAT_X8B8G8R8 && rgbaWriteMask != 0x0000000F)))   // FIXME: Need for masking when XBGR && Fh?
+				if(masked)
 				{
 					Short4 masked = value;
 					c23 &= *Pointer<Short4>(constants + OFFSET(Constants,maskB4Q[rgbaWriteMask][0]));
@@ -2026,7 +2039,7 @@
 			ASSERT(false);
 		}
 
-		if(postBlendSRGB && state.writeSRGB)
+		if((postBlendSRGB && state.writeSRGB) || isSRGB(index))
 		{
 			sRGBtoLinear(pixel.x);
 			sRGBtoLinear(pixel.y);