From 5a85fabfa618168a809d306ce67d43ec85efcdc4 Mon Sep 17 00:00:00 2001
From: Magnus Norddahl <dpjudas@users.noreply.github.com>
Date: Sun, 12 Feb 2017 01:27:26 +0100
Subject: [PATCH] Add true color support to voxel renderer

---
 src/r_data/voxels.cpp                      | 46 ++++++++++++++++++++++
 src/r_data/voxels.h                        | 10 +++++
 src/swrenderer/r_swrenderer.cpp            |  1 +
 src/swrenderer/things/r_voxel.cpp          | 14 ++++++-
 src/swrenderer/viewport/r_spritedrawer.cpp | 15 ++++++-
 5 files changed, 83 insertions(+), 3 deletions(-)

diff --git a/src/r_data/voxels.cpp b/src/r_data/voxels.cpp
index d81220ea8..4b8081288 100644
--- a/src/r_data/voxels.cpp
+++ b/src/r_data/voxels.cpp
@@ -392,6 +392,52 @@ FVoxel::~FVoxel()
 	if (Palette != NULL) delete [] Palette;
 }
 
+//==========================================================================
+//
+// Create true color version of the slab data
+//
+//==========================================================================
+
+void FVoxel::CreateBgraSlabData()
+{
+	assert(Palette != NULL);
+
+	for (int i = 0; i < NumMips; ++i)
+	{
+		int size = Mips[i].OffsetX[Mips[i].SizeX];
+		if (size <= 0) continue;
+
+		Mips[i].SlabDataBgra.Resize(size);
+
+		kvxslab_t *src = (kvxslab_t*)Mips[i].SlabData;
+		kvxslab_bgra_t *dest = (kvxslab_bgra_t*)&Mips[i].SlabDataBgra[0];
+
+		while (size >= 3)
+		{
+			dest->backfacecull = src->backfacecull;
+			dest->ztop = src->ztop;
+			dest->zleng = src->zleng;
+
+			int slabzleng = src->zleng;
+			for (int j = 0; j < slabzleng; ++j)
+			{
+				int colorIndex = src->col[j];
+
+				uint32_t red = (Palette[colorIndex * 3 + 0] << 2) | (Palette[colorIndex * 3 + 0] >> 4);
+				uint32_t green = (Palette[colorIndex * 3 + 1] << 2) | (Palette[colorIndex * 3 + 1] >> 4);
+				uint32_t blue = (Palette[colorIndex * 3 + 2] << 2) | (Palette[colorIndex * 3 + 2] >> 4);
+
+				dest->col[j] = 0xff000000 | (red << 16) | (green << 8) | blue;
+			}
+			slabzleng += 3;
+
+			dest = (kvxslab_bgra_t *)((uint32_t *)dest + slabzleng);
+			src = (kvxslab_t *)((BYTE *)src + slabzleng);
+			size -= slabzleng;
+		}
+	}
+}
+
 //==========================================================================
 //
 // Remap the voxel to the game palette
diff --git a/src/r_data/voxels.h b/src/r_data/voxels.h
index 85095c52f..df5839836 100644
--- a/src/r_data/voxels.h
+++ b/src/r_data/voxels.h
@@ -15,6 +15,14 @@ struct kvxslab_t
 	BYTE		col[1/*zleng*/];// color data from top to bottom
 };
 
+struct kvxslab_bgra_t
+{
+	uint32_t	ztop;			// starting z coordinate of top of slab
+	uint32_t	zleng;			// # of bytes in the color array - slab height
+	uint32_t	backfacecull;	// low 6 bits tell which of 6 faces are exposed
+	uint32_t	col[1/*zleng*/];// color data from top to bottom
+};
+
 struct FVoxelMipLevel
 {
 	FVoxelMipLevel();
@@ -27,6 +35,7 @@ struct FVoxelMipLevel
 	int			*OffsetX;
 	short		*OffsetXY;
 	BYTE		*SlabData;
+	TArray<uint32_t> SlabDataBgra;
 };
 
 struct FVoxel
@@ -39,6 +48,7 @@ struct FVoxel
 
 	FVoxel();
 	~FVoxel();
+	void CreateBgraSlabData();
 	void Remap();
 	void RemovePalette();
 };
diff --git a/src/swrenderer/r_swrenderer.cpp b/src/swrenderer/r_swrenderer.cpp
index 561f0de43..0366886ce 100644
--- a/src/swrenderer/r_swrenderer.cpp
+++ b/src/swrenderer/r_swrenderer.cpp
@@ -187,6 +187,7 @@ void FSoftwareRenderer::RemapVoxels()
 {
 	for (unsigned i=0; i<Voxels.Size(); i++)
 	{
+		Voxels[i]->CreateBgraSlabData();
 		Voxels[i]->Remap();
 	}
 }
diff --git a/src/swrenderer/things/r_voxel.cpp b/src/swrenderer/things/r_voxel.cpp
index ddb8d52c7..33e889c3f 100644
--- a/src/swrenderer/things/r_voxel.cpp
+++ b/src/swrenderer/things/r_voxel.cpp
@@ -538,6 +538,18 @@ namespace swrenderer
 								}
 								z2a[xxx] = MIN<int>(z2, dadmost[lxt + xxx]);
 							}
+
+							const uint8_t *columnColors = col;
+							bool bgra = viewport->RenderTarget->IsBgra();
+							if (bgra)
+							{
+								// The true color slab data array is identical, except its using uint32 instead of uint8.
+								//
+								// We can find the same slab column by calculating the offset from the start of SlabData
+								// and use that to offset into the BGRA version of the same data.
+								columnColors = (const uint8_t *)(&mip->SlabDataBgra[0] + (ptrdiff_t)(col - mip->SlabData));
+							}
+
 							// Find top and bottom pixels that match and draw them as one strip
 							for (int xxl = 0, xxr; xxl < stripwidth; )
 							{
@@ -559,7 +571,7 @@ namespace swrenderer
 								{
 									drawerargs.SetDest(lxt + x, z1);
 									drawerargs.SetCount(z2 - z1);
-									drawerargs.DrawVoxelColumn(thread, yplc[xxl], yinc, col, zleng);
+									drawerargs.DrawVoxelColumn(thread, yplc[xxl], yinc, columnColors, zleng);
 								}
 
 								/*
diff --git a/src/swrenderer/viewport/r_spritedrawer.cpp b/src/swrenderer/viewport/r_spritedrawer.cpp
index 0634bff70..cfcd3f285 100644
--- a/src/swrenderer/viewport/r_spritedrawer.cpp
+++ b/src/swrenderer/viewport/r_spritedrawer.cpp
@@ -499,8 +499,19 @@ namespace swrenderer
 
 	void SpriteDrawerArgs::DrawVoxelColumn(RenderThread *thread, fixed_t vPos, fixed_t vStep, const uint8_t *voxels, int voxelsCount)
 	{
-		dc_iscale = vStep;
-		dc_texturefrac = vPos;
+		if (RenderViewport::Instance()->RenderTarget->IsBgra())
+		{
+			double v = vPos / (double)voxelsCount / FRACUNIT;
+			double vstep = vStep / (double)voxelsCount / FRACUNIT;
+			dc_texturefrac = (int)(v * (1 << 30));
+			dc_iscale = (int)(vstep * (1 << 30));
+		}
+		else
+		{
+			dc_texturefrac = vPos;
+			dc_iscale = vStep;
+		}
+
 		dc_texturefracx = 0;
 		dc_source = voxels;
 		dc_source2 = 0;