diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 4669faace..723b95412 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -1063,6 +1063,7 @@ set( FASTMATH_PCH_SOURCES
 	r_segs.cpp
 	r_sky.cpp
 	r_things.cpp
+	r_triangle.cpp
 	s_advsound.cpp
 	s_environment.cpp
 	s_playlist.cpp
diff --git a/src/r_plane.cpp b/src/r_plane.cpp
index f39360b59..66738346f 100644
--- a/src/r_plane.cpp
+++ b/src/r_plane.cpp
@@ -59,7 +59,7 @@
 #include "v_palette.h"
 #include "r_data/colormaps.h"
 #include "r_draw_rgba.h"
-#include "gl/data/gl_matrix.h"
+#include "r_triangle.h"
 
 #ifdef _MSC_VER
 #pragma warning(disable:4244)
@@ -1015,6 +1015,250 @@ static const BYTE *R_GetTwoSkyColumns (FTexture *fronttex, int x)
 	}
 }
 
+static void R_DrawCubeSky(visplane_t *pl)
+{
+	int x1 = pl->left;
+	int x2 = pl->right;
+	short *uwal = (short *)pl->top;
+	short *dwal = (short *)pl->bottom;
+
+	static TriVertex cube[6 * 6] =
+	{
+		// Top
+		{ -1.0f,  1.0f,  0.6f, 1.0f, 1.0f, 0.0f, 1.0f },
+		{ 1.0f,  1.0f,  0.6f, 1.0f, 0.0f, 0.0f, 1.0f },
+		{ 1.0f, -1.0f,  0.6f, 1.0f, 0.0f, 0.1f, 1.0f },
+
+		{ 1.0f, -1.0f,  0.6f, 1.0f, 0.0f, 0.1f, 1.0f },
+		{ -1.0f, -1.0f,  0.6f, 1.0f, 1.0f, 0.1f, 1.0f },
+		{ -1.0f,  1.0f,  0.6f, 1.0f, 1.0f, 0.0f, 1.0f },
+
+		// Bottom
+		{ 1.0f, -1.0f, -1.0f, 1.0f, 1.0f, 0.9f, 1.0f },
+		{ 1.0f,  1.0f, -1.0f, 1.0f, 1.0f, 1.0f, 1.0f },
+		{ -1.0f,  1.0f, -1.0f, 1.0f, 0.0f, 1.0f, 1.0f },
+
+		{ -1.0f,  1.0f, -1.0f, 1.0f, 0.0f, 1.0f, 1.0f },
+		{ -1.0f, -1.0f, -1.0f, 1.0f, 0.0f, 0.9f, 1.0f },
+		{ 1.0f, -1.0f, -1.0f, 1.0f, 1.0f, 0.9f, 1.0f },
+
+		// Front
+		{ 1.0f,  1.0f, -1.0f, 1.0f, 1.0f, 2.0f, 1.0f },
+		{ 1.0f,  1.0f,  0.6f, 1.0f, 1.0f, 0.0f, 1.0f },
+		{ -1.0f,  1.0f,  0.6f, 1.0f, 0.0f, 0.0f, 1.0f },
+
+		{ -1.0f,  1.0f,  0.6f, 1.0f, 0.0f, 0.0f, 1.0f },
+		{ -1.0f,  1.0f, -1.0f, 1.0f, 0.0f, 2.0f, 1.0f },
+		{ 1.0f,  1.0f, -1.0f, 1.0f, 1.0f, 2.0f, 1.0f },
+
+		// Back
+		{ -1.0f, -1.0f,  0.6f, 1.0f, 1.0f, 0.0f, 1.0f },
+		{ 1.0f, -1.0f,  0.6f, 1.0f, 0.0f, 0.0f, 1.0f },
+		{ 1.0f, -1.0f, -1.0f, 1.0f, 0.0f, 2.0f, 1.0f },
+
+		{ 1.0f, -1.0f, -1.0f, 1.0f, 0.0f, 2.0f, 1.0f },
+		{ -1.0f, -1.0f, -1.0f, 1.0f, 1.0f, 2.0f, 1.0f },
+		{ -1.0f, -1.0f,  0.6f, 1.0f, 1.0f, 0.0f, 1.0f },
+
+		// Right
+		{ 1.0f, -1.0f,  0.6f, 1.0f, 1.0f, 0.0f, 1.0f },
+		{ 1.0f,  1.0f,  0.6f, 1.0f, 0.0f, 0.0f, 1.0f },
+		{ 1.0f,  1.0f, -1.0f, 1.0f, 0.0f, 2.0f, 1.0f },
+
+		{ 1.0f,  1.0f, -1.0f, 1.0f, 0.0f, 2.0f, 1.0f },
+		{ 1.0f, -1.0f, -1.0f, 1.0f, 1.0f, 2.0f, 1.0f },
+		{ 1.0f, -1.0f,  0.6f, 1.0f, 1.0f, 0.0f, 1.0f },
+
+		// Left
+		{ -1.0f,  1.0f, -1.0f, 1.0f, 1.0f, 2.0f, 1.0f },
+		{ -1.0f,  1.0f,  0.6f, 1.0f, 1.0f, 0.0f, 1.0f },
+		{ -1.0f, -1.0f,  0.6f, 1.0f, 0.0f, 0.0f, 1.0f },
+
+		{ -1.0f, -1.0f,  0.6f, 1.0f, 0.0f, 0.0f, 1.0f },
+		{ -1.0f, -1.0f, -1.0f, 1.0f, 0.0f, 2.0f, 1.0f },
+		{ -1.0f,  1.0f, -1.0f, 1.0f, 1.0f, 2.0f, 1.0f }
+	};
+
+	TriMatrix objectToWorld = TriMatrix::translate((float)ViewPos.X, (float)ViewPos.Y, (float)ViewPos.Z) * TriMatrix::scale(1000.0f, 1000.0f, 1000.0f);
+	TriMatrix objectToClip = TriMatrix::viewToClip() * TriMatrix::worldToView() * objectToWorld;
+	//TriMatrix objectToWorld = TriMatrix::scale(1000.0f, 1000.0f, 1000.0f);
+	//TriMatrix objectToClip = TriMatrix::viewToClip() * objectToWorld;
+
+	uint32_t solid_top = frontskytex->GetSkyCapColor(false);
+	uint32_t solid_bottom = frontskytex->GetSkyCapColor(true);
+
+	solid_top = RGB32k.RGB[(RPART(solid_top) >> 3)][(GPART(solid_top) >> 3)][(BPART(solid_top) >> 3)];
+	solid_bottom = RGB32k.RGB[(RPART(solid_bottom) >> 3)][(GPART(solid_bottom) >> 3)][(BPART(solid_bottom) >> 3)];
+
+	TriangleDrawer::fill(objectToClip, cube, 6, TriangleDrawMode::Normal, false, x1, x2 - 1, uwal, dwal, solid_top);
+	TriangleDrawer::fill(objectToClip, cube + 6, 6, TriangleDrawMode::Normal, false, x1, x2 - 1, uwal, dwal, solid_bottom);
+	TriangleDrawer::draw(objectToClip, cube + 2 * 6, 4 * 6, TriangleDrawMode::Normal, false, x1, x2 - 1, uwal, dwal, frontskytex);
+}
+
+namespace
+{
+	class SkyDome
+	{
+	public:
+		SkyDome() { CreateDome(); }
+		void Render(visplane_t *pl);
+
+	private:
+		TArray<TriVertex> mVertices;
+		TArray<unsigned int> mPrimStart;
+		int mRows, mColumns;
+
+		void SkyVertex(int r, int c, bool yflip);
+		void CreateSkyHemisphere(bool zflip);
+		void CreateDome();
+		void RenderRow(int row, visplane_t *pl);
+		void RenderCapColorRow(int row, bool bottomCap, visplane_t *pl);
+
+		TriVertex SetVertex(float xx, float yy, float zz, float uu = 0, float vv = 0);
+		TriVertex SetVertexXYZ(float xx, float yy, float zz, float uu = 0, float vv = 0);
+	};
+
+	TriVertex SkyDome::SetVertex(float xx, float yy, float zz, float uu, float vv)
+	{
+		TriVertex v;
+		v.x = xx;
+		v.y = yy;
+		v.z = zz;
+		v.w = 1.0f;
+		v.varying[0] = uu;
+		v.varying[1] = vv;
+		v.varying[2] = 1.0f;
+		return v;
+	}
+
+	TriVertex SkyDome::SetVertexXYZ(float xx, float yy, float zz, float uu, float vv)
+	{
+		TriVertex v;
+		v.x = xx;
+		v.y = zz;
+		v.z = yy;
+		v.w = 1.0f;
+		v.varying[0] = uu;
+		v.varying[1] = vv;
+		v.varying[2] = 1.0f;
+		return v;
+	}
+
+	void SkyDome::SkyVertex(int r, int c, bool zflip)
+	{
+		static const FAngle maxSideAngle = 60.f;
+		static const float scale = 10000.;
+
+		FAngle topAngle = (c / (float)mColumns * 360.f);
+		FAngle sideAngle = maxSideAngle * (mRows - r) / mRows;
+		float height = sideAngle.Sin();
+		float realRadius = scale * sideAngle.Cos();
+		FVector2 pos = topAngle.ToVector(realRadius);
+		float z = (!zflip) ? scale * height : -scale * height;
+
+		float u, v;
+		//uint32_t color = r == 0 ? 0xffffff : 0xffffffff;
+
+		// And the texture coordinates.
+		if (!zflip)	// Flipped Y is for the lower hemisphere.
+		{
+			u = (-c / (float)mColumns);
+			v = (r / (float)mRows);
+		}
+		else
+		{
+			u = (-c / (float)mColumns);
+			v = 1.0f + ((mRows - r) / (float)mRows);
+		}
+
+		if (r != 4) z += 300;
+
+		// And finally the vertex.
+		TriVertex vert;
+		vert = SetVertexXYZ(-pos.X, z - 1.f, pos.Y, u * 4.0f, v + 0.5f/*, color*/);
+		mVertices.Push(vert);
+	}
+
+	void SkyDome::CreateSkyHemisphere(bool zflip)
+	{
+		int r, c;
+
+		mPrimStart.Push(mVertices.Size());
+
+		for (c = 0; c < mColumns; c++)
+		{
+			SkyVertex(1, c, zflip);
+		}
+
+		// The total number of triangles per hemisphere can be calculated
+		// as follows: rows * columns * 2 + 2 (for the top cap).
+		for (r = 0; r < mRows; r++)
+		{
+			mPrimStart.Push(mVertices.Size());
+			for (c = 0; c <= mColumns; c++)
+			{
+				SkyVertex(r + zflip, c, zflip);
+				SkyVertex(r + 1 - zflip, c, zflip);
+			}
+		}
+	}
+
+	void SkyDome::CreateDome()
+	{
+		mColumns = 128;
+		mRows = 4;
+		CreateSkyHemisphere(false);
+		CreateSkyHemisphere(true);
+		mPrimStart.Push(mVertices.Size());
+	}
+
+	void SkyDome::RenderRow(int row, visplane_t *pl)
+	{
+		int x1 = pl->left;
+		int x2 = pl->right;
+		short *uwal = (short *)pl->top;
+		short *dwal = (short *)pl->bottom;
+		TriMatrix objectToWorld = TriMatrix::translate((float)ViewPos.X, (float)ViewPos.Y, (float)ViewPos.Z);
+		TriMatrix objectToClip = TriMatrix::viewToClip() * TriMatrix::worldToView() * objectToWorld;
+		TriangleDrawer::draw(objectToClip, &mVertices[mPrimStart[row]], mPrimStart[row + 1] - mPrimStart[row], TriangleDrawMode::Strip, false, x1, x2 - 1, uwal, dwal, frontskytex);
+	}
+
+	void SkyDome::RenderCapColorRow(int row, bool bottomCap, visplane_t *pl)
+	{
+		uint32_t solid = frontskytex->GetSkyCapColor(bottomCap);
+		solid = RGB32k.RGB[(RPART(solid) >> 3)][(GPART(solid) >> 3)][(BPART(solid) >> 3)];
+
+		int x1 = pl->left;
+		int x2 = pl->right;
+		short *uwal = (short *)pl->top;
+		short *dwal = (short *)pl->bottom;
+		TriMatrix objectToWorld = TriMatrix::translate((float)ViewPos.X, (float)ViewPos.Y, (float)ViewPos.Z);
+		TriMatrix objectToClip = TriMatrix::viewToClip() * TriMatrix::worldToView() * objectToWorld;
+		TriangleDrawer::fill(objectToClip, &mVertices[mPrimStart[row]], mPrimStart[row + 1] - mPrimStart[row], TriangleDrawMode::Fan, bottomCap, x1, x2 - 1, uwal, dwal, solid);
+	}
+
+	void SkyDome::Render(visplane_t *pl)
+	{
+		int rc = mRows + 1;
+
+		// No need to draw this as the software renderer can't look that high anyway
+		//RenderCapColorRow(0, false, pl);
+		//RenderCapColorRow(rc, true, pl);
+
+		for (int i = 1; i <= mRows; i++)
+		{
+			RenderRow(i, pl);
+			RenderRow(rc + i, pl);
+		}
+	}
+}
+
+static void R_DrawDomeSky(visplane_t *pl)
+{
+	static SkyDome skydome;
+	skydome.Render(pl);
+}
+
 static void R_DrawSkyColumnStripe(int start_x, int y1, int y2, int columns, double scale, double texturemid, double yrepeat)
 {
 	uint32_t height = frontskytex->GetHeight();
@@ -1212,6 +1456,16 @@ static void R_DrawSky (visplane_t *pl)
 		R_DrawCapSky(pl);
 		return;
 	}
+	else if (r_skymode == 3)
+	{
+		R_DrawCubeSky(pl);
+		return;
+	}
+	else if (r_skymode == 4)
+	{
+		R_DrawDomeSky(pl);
+		return;
+	}
 
 	int x;
 	float swal;
diff --git a/src/r_triangle.cpp b/src/r_triangle.cpp
new file mode 100644
index 000000000..b039ed1ff
--- /dev/null
+++ b/src/r_triangle.cpp
@@ -0,0 +1,772 @@
+/*
+**  Triangle drawers
+**  Copyright (c) 2016 Magnus Norddahl
+**
+**  This software is provided 'as-is', without any express or implied
+**  warranty.  In no event will the authors be held liable for any damages
+**  arising from the use of this software.
+**
+**  Permission is granted to anyone to use this software for any purpose,
+**  including commercial applications, and to alter it and redistribute it
+**  freely, subject to the following restrictions:
+**
+**  1. The origin of this software must not be misrepresented; you must not
+**     claim that you wrote the original software. If you use this software
+**     in a product, an acknowledgment in the product documentation would be
+**     appreciated but is not required.
+**  2. Altered source versions must be plainly marked as such, and must not be
+**     misrepresented as being the original software.
+**  3. This notice may not be removed or altered from any source distribution.
+**
+*/
+
+#include <stddef.h>
+#include "templates.h"
+#include "doomdef.h"
+#include "i_system.h"
+#include "w_wad.h"
+#include "r_local.h"
+#include "v_video.h"
+#include "doomstat.h"
+#include "st_stuff.h"
+#include "g_game.h"
+#include "g_level.h"
+#include "r_data/r_translate.h"
+#include "v_palette.h"
+#include "r_data/colormaps.h"
+#include "r_triangle.h"
+
+void TriangleDrawer::draw(const TriMatrix &objectToClip, const TriVertex *vinput, int vcount, TriangleDrawMode mode, bool ccw, int clipleft, int clipright, const short *cliptop, const short *clipbottom, FTexture *texture)
+{
+	draw_arrays(objectToClip, vinput, vcount, mode, ccw, clipleft, clipright, cliptop, clipbottom, texture, 0, &ScreenTriangleDrawer::draw);
+}
+
+void TriangleDrawer::fill(const TriMatrix &objectToClip, const TriVertex *vinput, int vcount, TriangleDrawMode mode, bool ccw, int clipleft, int clipright, const short *cliptop, const short *clipbottom, int solidcolor)
+{
+	draw_arrays(objectToClip, vinput, vcount, mode, ccw, clipleft, clipright, cliptop, clipbottom, nullptr, solidcolor, &ScreenTriangleDrawer::fill);
+}
+
+void TriangleDrawer::draw_arrays(const TriMatrix &objectToClip, const TriVertex *vinput, int vcount, TriangleDrawMode mode, bool ccw, int clipleft, int clipright, const short *cliptop, const short *clipbottom, FTexture *texture, int solidcolor, void(*drawfunc)(const ScreenTriangleDrawerArgs *))
+{
+	if (vcount < 3)
+		return;
+
+	ScreenTriangleDrawerArgs args;
+	args.dest = dc_destorg;
+	args.pitch = dc_pitch;
+	args.clipleft = clipleft;
+	args.clipright = clipright;
+	args.cliptop = cliptop;
+	args.clipbottom = clipbottom;
+	if (texture)
+	{
+		args.textureWidth = texture->GetWidth();
+		args.textureHeight = texture->GetHeight();
+		args.texturePixels = texture->GetPixels();
+	}
+	else
+	{
+		args.textureWidth = 0;
+		args.textureHeight = 0;
+		args.texturePixels = nullptr;
+	}
+	args.solidcolor = solidcolor;
+
+	TriVertex vert[3];
+	if (mode == TriangleDrawMode::Normal)
+	{
+		for (int i = 0; i < vcount / 3; i++)
+		{
+			for (int j = 0; j < 3; j++)
+				vert[j] = shade_vertex(objectToClip, *(vinput++));
+			draw_shaded_triangle(vert, ccw, &args, drawfunc);
+		}
+	}
+	else if (mode == TriangleDrawMode::Fan)
+	{
+		vert[0] = shade_vertex(objectToClip, *(vinput++));
+		vert[1] = shade_vertex(objectToClip, *(vinput++));
+		for (int i = 2; i < vcount; i++)
+		{
+			vert[2] = shade_vertex(objectToClip, *(vinput++));
+			draw_shaded_triangle(vert, ccw, &args, drawfunc);
+			vert[1] = vert[2];
+		}
+	}
+	else // TriangleDrawMode::Strip
+	{
+		vert[0] = shade_vertex(objectToClip, *(vinput++));
+		vert[1] = shade_vertex(objectToClip, *(vinput++));
+		for (int i = 2; i < vcount; i++)
+		{
+			vert[2] = shade_vertex(objectToClip, *(vinput++));
+			draw_shaded_triangle(vert, ccw, &args, drawfunc);
+			vert[0] = vert[1];
+			vert[1] = vert[2];
+			ccw = !ccw;
+		}
+	}
+}
+
+TriVertex TriangleDrawer::shade_vertex(const TriMatrix &objectToClip, TriVertex v)
+{
+	// Apply transform to get clip coordinates:
+	return objectToClip * v;
+}
+
+void TriangleDrawer::draw_shaded_triangle(const TriVertex *vert, bool ccw, ScreenTriangleDrawerArgs *args, void(*drawfunc)(const ScreenTriangleDrawerArgs *))
+{
+	// Cull, clip and generate additional vertices as needed
+	TriVertex clippedvert[6];
+	int numclipvert = 0;
+	clipedge(vert[0], vert[1], clippedvert, numclipvert);
+	clipedge(vert[1], vert[2], clippedvert, numclipvert);
+	clipedge(vert[2], vert[0], clippedvert, numclipvert);
+
+	// Map to 2D viewport:
+	for (int j = 0; j < numclipvert; j++)
+	{
+		auto &v = clippedvert[j];
+
+		// Calculate normalized device coordinates:
+		v.w = 1.0f / v.w;
+		v.x *= v.w;
+		v.y *= v.w;
+		v.z *= v.w;
+
+		// Apply viewport scale to get screen coordinates:
+		v.x = viewwidth * (1.0f + v.x) * 0.5f;
+		v.y = viewheight * (1.0f - v.y) * 0.5f;
+	}
+
+	// Draw screen triangles
+	if (ccw)
+	{
+		for (int i = numclipvert; i > 1; i--)
+		{
+			args->v1 = &clippedvert[numclipvert - 1];
+			args->v2 = &clippedvert[i - 1];
+			args->v3 = &clippedvert[i - 2];
+			drawfunc(args);
+		}
+	}
+	else
+	{
+		for (int i = 2; i < numclipvert; i++)
+		{
+			args->v1 = &clippedvert[0];
+			args->v2 = &clippedvert[i - 1];
+			args->v3 = &clippedvert[i];
+			drawfunc(args);
+		}
+	}
+}
+
+bool TriangleDrawer::cullhalfspace(float clipdistance1, float clipdistance2, float &t1, float &t2)
+{
+	float d1 = clipdistance1 * (1.0f - t1) + clipdistance2 * t1;
+	float d2 = clipdistance1 * (1.0f - t2) + clipdistance2 * t2;
+	if (d1 < 0.0f && d2 < 0.0f)
+		return true;
+
+	if (d1 < 0.0f)
+		t1 = MAX(-clipdistance1 / (clipdistance2 - clipdistance1), t1);
+
+	if (d2 < 0.0f)
+		t2 = MIN(1.0f + clipdistance2 / (clipdistance1 - clipdistance2), t2);
+
+	return false;
+}
+
+void TriangleDrawer::clipedge(const TriVertex &v1, const TriVertex &v2, TriVertex *clippedvert, int &numclipvert)
+{
+	// Clip and cull so that the following is true for all vertices:
+	// -v.w <= v.x <= v.w
+	// -v.w <= v.y <= v.w
+	// -v.w <= v.z <= v.w
+
+	float t1 = 0.0f, t2 = 1.0f;
+	bool culled =
+		cullhalfspace(v1.x + v1.w, v2.x + v2.w, t1, t2) ||
+		cullhalfspace(v1.w - v1.x, v2.w - v2.x, t1, t2) ||
+		cullhalfspace(v1.y + v1.w, v2.y + v2.w, t1, t2) ||
+		cullhalfspace(v1.w - v1.y, v2.w - v2.y, t1, t2) ||
+		cullhalfspace(v1.z + v1.w, v2.z + v2.w, t1, t2) ||
+		cullhalfspace(v1.w - v1.z, v2.w - v2.z, t1, t2);
+	if (culled)
+		return;
+
+	if (t1 == 0.0f)
+	{
+		clippedvert[numclipvert++] = v1;
+	}
+	else
+	{
+		auto &v = clippedvert[numclipvert++];
+		v.x = v1.x * (1.0f - t1) + v2.x * t1;
+		v.y = v1.y * (1.0f - t1) + v2.y * t1;
+		v.z = v1.z * (1.0f - t1) + v2.z * t1;
+		v.w = v1.w * (1.0f - t1) + v2.w * t1;
+		for (int i = 0; i < TriVertex::NumVarying; i++)
+			v.varying[i] = v1.varying[i] * (1.0f - t1) + v2.varying[i] * t1;
+	}
+
+	if (t2 != 1.0f)
+	{
+		auto &v = clippedvert[numclipvert++];
+		v.x = v1.x * (1.0f - t2) + v2.x * t2;
+		v.y = v1.y * (1.0f - t2) + v2.y * t2;
+		v.z = v1.z * (1.0f - t2) + v2.z * t2;
+		v.w = v1.w * (1.0f - t2) + v2.w * t2;
+		for (int i = 0; i < TriVertex::NumVarying; i++)
+			v.varying[i] = v1.varying[i] * (1.0f - t2) + v2.varying[i] * t2;
+	}
+}
+
+/////////////////////////////////////////////////////////////////////////////
+
+void ScreenTriangleDrawer::draw(const ScreenTriangleDrawerArgs *args)
+{
+	uint8_t *dest = args->dest;
+	int pitch = args->pitch;
+	const TriVertex &v1 = *args->v1;
+	const TriVertex &v2 = *args->v2;
+	const TriVertex &v3 = *args->v3;
+	int clipleft = args->clipleft;
+	int clipright = args->clipright;
+	const short *cliptop = args->cliptop;
+	const short *clipbottom = args->clipbottom;
+	const uint8_t *texturePixels = args->texturePixels;
+	int textureWidth = args->textureWidth;
+	int textureHeight = args->textureHeight;
+
+	// 28.4 fixed-point coordinates
+	const int Y1 = (int)round(16.0f * v1.y);
+	const int Y2 = (int)round(16.0f * v2.y);
+	const int Y3 = (int)round(16.0f * v3.y);
+
+	const int X1 = (int)round(16.0f * v1.x);
+	const int X2 = (int)round(16.0f * v2.x);
+	const int X3 = (int)round(16.0f * v3.x);
+
+	// Deltas
+	const int DX12 = X1 - X2;
+	const int DX23 = X2 - X3;
+	const int DX31 = X3 - X1;
+
+	const int DY12 = Y1 - Y2;
+	const int DY23 = Y2 - Y3;
+	const int DY31 = Y3 - Y1;
+
+	// Fixed-point deltas
+	const int FDX12 = DX12 << 4;
+	const int FDX23 = DX23 << 4;
+	const int FDX31 = DX31 << 4;
+
+	const int FDY12 = DY12 << 4;
+	const int FDY23 = DY23 << 4;
+	const int FDY31 = DY31 << 4;
+
+	// Bounding rectangle
+	int clipymin = cliptop[clipleft];
+	int clipymax = clipbottom[clipleft];
+	for (int i = clipleft + 1; i <= clipright; i++)
+	{
+		clipymin = MIN(clipymin, (int)cliptop[i]);
+		clipymax = MAX(clipymax, (int)clipbottom[i]);
+	}
+	int minx = MAX((MIN(MIN(X1, X2), X3) + 0xF) >> 4, clipleft);
+	int maxx = MIN((MAX(MAX(X1, X2), X3) + 0xF) >> 4, clipright);
+	int miny = MAX((MIN(MIN(Y1, Y2), Y3) + 0xF) >> 4, clipymin);
+	int maxy = MIN((MAX(MAX(Y1, Y2), Y3) + 0xF) >> 4, clipymax - 1);
+	if (minx >= maxx || miny >= maxy)
+		return;
+
+	// Block size, standard 8x8 (must be power of two)
+	const int q = 8;
+
+	// Start in corner of 8x8 block
+	minx &= ~(q - 1);
+	miny &= ~(q - 1);
+
+	dest += miny * pitch;
+
+	// Half-edge constants
+	int C1 = DY12 * X1 - DX12 * Y1;
+	int C2 = DY23 * X2 - DX23 * Y2;
+	int C3 = DY31 * X3 - DX31 * Y3;
+
+	// Correct for fill convention
+	if (DY12 < 0 || (DY12 == 0 && DX12 > 0)) C1++;
+	if (DY23 < 0 || (DY23 == 0 && DX23 > 0)) C2++;
+	if (DY31 < 0 || (DY31 == 0 && DX31 > 0)) C3++;
+
+	// Gradients
+	float gradWX = gradx(v1.x, v1.y, v2.x, v2.y, v3.x, v3.y, v1.w, v2.w, v3.w);
+	float gradWY = grady(v1.x, v1.y, v2.x, v2.y, v3.x, v3.y, v1.w, v2.w, v3.w);
+	float startW = v1.w + gradWX * (minx - v1.x) + gradWY * (miny - v1.y);
+	float gradVaryingX[TriVertex::NumVarying], gradVaryingY[TriVertex::NumVarying], startVarying[TriVertex::NumVarying];
+	for (int i = 0; i < TriVertex::NumVarying; i++)
+	{
+		gradVaryingX[i] = gradx(v1.x, v1.y, v2.x, v2.y, v3.x, v3.y, v1.varying[i] * v1.w, v2.varying[i] * v2.w, v3.varying[i] * v3.w);
+		gradVaryingY[i] = grady(v1.x, v1.y, v2.x, v2.y, v3.x, v3.y, v1.varying[i] * v1.w, v2.varying[i] * v2.w, v3.varying[i] * v3.w);
+		startVarying[i] = v1.varying[i] * v1.w + gradVaryingX[i] * (minx - v1.x) + gradVaryingY[i] * (miny - v1.y);
+	}
+
+	// Loop through blocks
+	for (int y = miny; y < maxy; y += q)
+	{
+		for (int x = minx; x < maxx; x += q)
+		{
+			// Corners of block
+			int x0 = x << 4;
+			int x1 = (x + q - 1) << 4;
+			int y0 = y << 4;
+			int y1 = (y + q - 1) << 4;
+
+			// Evaluate half-space functions
+			bool a00 = C1 + DX12 * y0 - DY12 * x0 > 0;
+			bool a10 = C1 + DX12 * y0 - DY12 * x1 > 0;
+			bool a01 = C1 + DX12 * y1 - DY12 * x0 > 0;
+			bool a11 = C1 + DX12 * y1 - DY12 * x1 > 0;
+			int a = (a00 << 0) | (a10 << 1) | (a01 << 2) | (a11 << 3);
+
+			bool b00 = C2 + DX23 * y0 - DY23 * x0 > 0;
+			bool b10 = C2 + DX23 * y0 - DY23 * x1 > 0;
+			bool b01 = C2 + DX23 * y1 - DY23 * x0 > 0;
+			bool b11 = C2 + DX23 * y1 - DY23 * x1 > 0;
+			int b = (b00 << 0) | (b10 << 1) | (b01 << 2) | (b11 << 3);
+
+			bool c00 = C3 + DX31 * y0 - DY31 * x0 > 0;
+			bool c10 = C3 + DX31 * y0 - DY31 * x1 > 0;
+			bool c01 = C3 + DX31 * y1 - DY31 * x0 > 0;
+			bool c11 = C3 + DX31 * y1 - DY31 * x1 > 0;
+			int c = (c00 << 0) | (c10 << 1) | (c01 << 2) | (c11 << 3);
+
+			// Skip block when outside an edge
+			if (a == 0x0 || b == 0x0 || c == 0x0) continue;
+
+			// Check if block needs clipping
+			int clipcount = 0;
+			for (int ix = x; ix < x + q; ix++)
+			{
+				clipcount += (clipleft > ix) || (clipright < ix) || (cliptop[ix] > y) || (clipbottom[ix] <= y + q - 1);
+			}
+
+			// Calculate varying variables for affine block
+			float offx0 = (x - minx) + 0.5f;
+			float offy0 = (y - miny) + 0.5f;
+			float offx1 = offx0 + q;
+			float offy1 = offy0 + q;
+			float rcpWTL = 1.0f / (startW + offx0 * gradWX + offy0 * gradWY);
+			float rcpWTR = 1.0f / (startW + offx1 * gradWX + offy0 * gradWY);
+			float rcpWBL = 1.0f / (startW + offx0 * gradWX + offy1 * gradWY);
+			float rcpWBR = 1.0f / (startW + offx1 * gradWX + offy1 * gradWY);
+			float varyingTL[TriVertex::NumVarying];
+			float varyingTR[TriVertex::NumVarying];
+			float varyingBL[TriVertex::NumVarying];
+			float varyingBR[TriVertex::NumVarying];
+			for (int i = 0; i < TriVertex::NumVarying; i++)
+			{
+				varyingTL[i] = (startVarying[i] + offx0 * gradVaryingX[i] + offy0 * gradVaryingY[i]) * rcpWTL;
+				varyingTR[i] = (startVarying[i] + offx1 * gradVaryingX[i] + offy0 * gradVaryingY[i]) * rcpWTR;
+				varyingBL[i] = ((startVarying[i] + offx0 * gradVaryingX[i] + offy1 * gradVaryingY[i]) * rcpWBL - varyingTL[i]) * (1.0f / q);
+				varyingBR[i] = ((startVarying[i] + offx1 * gradVaryingX[i] + offy1 * gradVaryingY[i]) * rcpWBR - varyingTR[i]) * (1.0f / q);
+			}
+
+			uint8_t *buffer = dest;
+
+			// Accept whole block when totally covered
+			if (a == 0xF && b == 0xF && c == 0xF && clipcount == 0)
+			{
+				for (int iy = 0; iy < q; iy++)
+				{
+					float varying[TriVertex::NumVarying], varyingStep[TriVertex::NumVarying];
+					for (int i = 0; i < TriVertex::NumVarying; i++)
+					{
+						varying[i] = varyingTL[i] + varyingBL[i] * iy;
+						varyingStep[i] = (varyingTR[i] + varyingBR[i] * iy - varying[i]) * (1.0f / q);
+					}
+
+					for (int ix = x; ix < x + q; ix++)
+					{
+						uint32_t ufrac = (uint32_t)((varying[0] - floor(varying[0])) * 0x100000000LL);
+						uint32_t vfrac = (uint32_t)((varying[1] - floor(varying[1])) * 0x100000000LL);
+						//uint32_t light = (uint32_t)clamp(varying[2] * 255.0f + 0.5f, 0.0f, 255.0f);
+
+						uint32_t upos = ((ufrac >> 16) * textureWidth) >> 16;
+						uint32_t vpos = ((vfrac >> 16) * textureHeight) >> 16;
+						uint32_t uvoffset = upos * textureHeight + vpos;
+
+						buffer[ix] = texturePixels[uvoffset];
+
+						for (int i = 0; i < TriVertex::NumVarying; i++)
+							varying[i] += varyingStep[i];
+					}
+
+					buffer += pitch;
+				}
+			}
+			else // Partially covered block
+			{
+				int CY1 = C1 + DX12 * y0 - DY12 * x0;
+				int CY2 = C2 + DX23 * y0 - DY23 * x0;
+				int CY3 = C3 + DX31 * y0 - DY31 * x0;
+
+				for (int iy = 0; iy < q; iy++)
+				{
+					int CX1 = CY1;
+					int CX2 = CY2;
+					int CX3 = CY3;
+
+					float varying[TriVertex::NumVarying], varyingStep[TriVertex::NumVarying];
+					for (int i = 0; i < TriVertex::NumVarying; i++)
+					{
+						varying[i] = varyingTL[i] + varyingBL[i] * iy;
+						varyingStep[i] = (varyingTR[i] + varyingBR[i] * iy - varying[i]) * (1.0f / q);
+					}
+
+					for (int ix = x; ix < x + q; ix++)
+					{
+						bool visible = ix >= clipleft && ix <= clipright && (cliptop[ix] <= y + iy) && (clipbottom[ix] > y + iy);
+
+						if (CX1 > 0 && CX2 > 0 && CX3 > 0 && visible)
+						{
+							uint32_t ufrac = (uint32_t)((varying[0] - floor(varying[0])) * 0x100000000LL);
+							uint32_t vfrac = (uint32_t)((varying[1] - floor(varying[1])) * 0x100000000LL);
+							//uint32_t light = (uint32_t)clamp(varying[2] * 255.0f + 0.5f, 0.0f, 255.0f);
+
+							uint32_t upos = ((ufrac >> 16) * textureWidth) >> 16;
+							uint32_t vpos = ((vfrac >> 16) * textureHeight) >> 16;
+							uint32_t uvoffset = upos * textureHeight + vpos;
+
+							buffer[ix] = texturePixels[uvoffset];
+						}
+
+						for (int i = 0; i < TriVertex::NumVarying; i++)
+							varying[i] += varyingStep[i];
+
+						CX1 -= FDY12;
+						CX2 -= FDY23;
+						CX3 -= FDY31;
+					}
+
+					CY1 += FDX12;
+					CY2 += FDX23;
+					CY3 += FDX31;
+
+					buffer += pitch;
+				}
+			}
+		}
+
+		dest += q * pitch;
+	}
+}
+
+void ScreenTriangleDrawer::fill(const ScreenTriangleDrawerArgs *args)
+{
+	uint8_t *dest = args->dest;
+	int pitch = args->pitch;
+	const TriVertex &v1 = *args->v1;
+	const TriVertex &v2 = *args->v2;
+	const TriVertex &v3 = *args->v3;
+	int clipleft = args->clipleft;
+	int clipright = args->clipright;
+	const short *cliptop = args->cliptop;
+	const short *clipbottom = args->clipbottom;
+	int solidcolor = args->solidcolor;
+
+	// 28.4 fixed-point coordinates
+	const int Y1 = (int)round(16.0f * v1.y);
+	const int Y2 = (int)round(16.0f * v2.y);
+	const int Y3 = (int)round(16.0f * v3.y);
+
+	const int X1 = (int)round(16.0f * v1.x);
+	const int X2 = (int)round(16.0f * v2.x);
+	const int X3 = (int)round(16.0f * v3.x);
+
+	// Deltas
+	const int DX12 = X1 - X2;
+	const int DX23 = X2 - X3;
+	const int DX31 = X3 - X1;
+
+	const int DY12 = Y1 - Y2;
+	const int DY23 = Y2 - Y3;
+	const int DY31 = Y3 - Y1;
+
+	// Fixed-point deltas
+	const int FDX12 = DX12 << 4;
+	const int FDX23 = DX23 << 4;
+	const int FDX31 = DX31 << 4;
+
+	const int FDY12 = DY12 << 4;
+	const int FDY23 = DY23 << 4;
+	const int FDY31 = DY31 << 4;
+
+	// Bounding rectangle
+	int clipymin = cliptop[clipleft];
+	int clipymax = clipbottom[clipleft];
+	for (int i = clipleft + 1; i <= clipright; i++)
+	{
+		clipymin = MIN(clipymin, (int)cliptop[i]);
+		clipymax = MAX(clipymax, (int)clipbottom[i]);
+	}
+	int minx = MAX((MIN(MIN(X1, X2), X3) + 0xF) >> 4, clipleft);
+	int maxx = MIN((MAX(MAX(X1, X2), X3) + 0xF) >> 4, clipright);
+	int miny = MAX((MIN(MIN(Y1, Y2), Y3) + 0xF) >> 4, clipymin);
+	int maxy = MIN((MAX(MAX(Y1, Y2), Y3) + 0xF) >> 4, clipymax - 1);
+	if (minx >= maxx || miny >= maxy)
+		return;
+
+	// Block size, standard 8x8 (must be power of two)
+	const int q = 8;
+
+	// Start in corner of 8x8 block
+	minx &= ~(q - 1);
+	miny &= ~(q - 1);
+
+	dest += miny * pitch;
+
+	// Half-edge constants
+	int C1 = DY12 * X1 - DX12 * Y1;
+	int C2 = DY23 * X2 - DX23 * Y2;
+	int C3 = DY31 * X3 - DX31 * Y3;
+
+	// Correct for fill convention
+	if (DY12 < 0 || (DY12 == 0 && DX12 > 0)) C1++;
+	if (DY23 < 0 || (DY23 == 0 && DX23 > 0)) C2++;
+	if (DY31 < 0 || (DY31 == 0 && DX31 > 0)) C3++;
+
+	// Loop through blocks
+	for (int y = miny; y < maxy; y += q)
+	{
+		for (int x = minx; x < maxx; x += q)
+		{
+			// Corners of block
+			int x0 = x << 4;
+			int x1 = (x + q - 1) << 4;
+			int y0 = y << 4;
+			int y1 = (y + q - 1) << 4;
+
+			// Evaluate half-space functions
+			bool a00 = C1 + DX12 * y0 - DY12 * x0 > 0;
+			bool a10 = C1 + DX12 * y0 - DY12 * x1 > 0;
+			bool a01 = C1 + DX12 * y1 - DY12 * x0 > 0;
+			bool a11 = C1 + DX12 * y1 - DY12 * x1 > 0;
+			int a = (a00 << 0) | (a10 << 1) | (a01 << 2) | (a11 << 3);
+
+			bool b00 = C2 + DX23 * y0 - DY23 * x0 > 0;
+			bool b10 = C2 + DX23 * y0 - DY23 * x1 > 0;
+			bool b01 = C2 + DX23 * y1 - DY23 * x0 > 0;
+			bool b11 = C2 + DX23 * y1 - DY23 * x1 > 0;
+			int b = (b00 << 0) | (b10 << 1) | (b01 << 2) | (b11 << 3);
+
+			bool c00 = C3 + DX31 * y0 - DY31 * x0 > 0;
+			bool c10 = C3 + DX31 * y0 - DY31 * x1 > 0;
+			bool c01 = C3 + DX31 * y1 - DY31 * x0 > 0;
+			bool c11 = C3 + DX31 * y1 - DY31 * x1 > 0;
+			int c = (c00 << 0) | (c10 << 1) | (c01 << 2) | (c11 << 3);
+
+			// Skip block when outside an edge
+			if (a == 0x0 || b == 0x0 || c == 0x0) continue;
+
+			// Check if block needs clipping
+			int clipcount = 0;
+			for (int ix = x; ix < x + q; ix++)
+			{
+				clipcount += (clipleft > ix) || (clipright < ix) || (cliptop[ix] > y) || (clipbottom[ix] <= y + q - 1);
+			}
+
+			uint8_t *buffer = dest;
+
+			// Accept whole block when totally covered
+			if (a == 0xF && b == 0xF && c == 0xF && clipcount == 0)
+			{
+				for (int iy = 0; iy < q; iy++)
+				{
+					for (int ix = x; ix < x + q; ix++)
+					{
+						buffer[ix] = solidcolor;
+					}
+
+					buffer += pitch;
+				}
+			}
+			else // Partially covered block
+			{
+				int CY1 = C1 + DX12 * y0 - DY12 * x0;
+				int CY2 = C2 + DX23 * y0 - DY23 * x0;
+				int CY3 = C3 + DX31 * y0 - DY31 * x0;
+
+				for (int iy = 0; iy < q; iy++)
+				{
+					int CX1 = CY1;
+					int CX2 = CY2;
+					int CX3 = CY3;
+
+					for (int ix = x; ix < x + q; ix++)
+					{
+						bool visible = ix >= clipleft && ix <= clipright && (cliptop[ix] <= y + iy) && (clipbottom[ix] > y + iy);
+
+						if (CX1 > 0 && CX2 > 0 && CX3 > 0 && visible)
+						{
+							buffer[ix] = solidcolor;
+						}
+
+						CX1 -= FDY12;
+						CX2 -= FDY23;
+						CX3 -= FDY31;
+					}
+
+					CY1 += FDX12;
+					CY2 += FDX23;
+					CY3 += FDX31;
+
+					buffer += pitch;
+				}
+			}
+		}
+
+		dest += q * pitch;
+	}
+}
+
+float ScreenTriangleDrawer::gradx(float x0, float y0, float x1, float y1, float x2, float y2, float c0, float c1, float c2)
+{
+	float top = (c1 - c2) * (y0 - y2) - (c0 - c2) * (y1 - y2);
+	float bottom = (x1 - x2) * (y0 - y2) - (x0 - x2) * (y1 - y2);
+	return top / bottom;
+}
+
+float ScreenTriangleDrawer::grady(float x0, float y0, float x1, float y1, float x2, float y2, float c0, float c1, float c2)
+{
+	float top = (c1 - c2) * (x0 - x2) - (c0 - c2) * (x1 - x2);
+	float bottom = -((x1 - x2) * (y0 - y2) - (x0 - x2) * (y1 - y2));
+	return top / bottom;
+}
+
+/////////////////////////////////////////////////////////////////////////////
+
+TriMatrix TriMatrix::null()
+{
+	TriMatrix m;
+	memset(m.matrix, 0, sizeof(m.matrix));
+	return m;
+}
+
+TriMatrix TriMatrix::identity()
+{
+	TriMatrix m = null();
+	m.matrix[0] = 1.0f;
+	m.matrix[5] = 1.0f;
+	m.matrix[10] = 1.0f;
+	m.matrix[15] = 1.0f;
+	return m;
+}
+
+TriMatrix TriMatrix::translate(float x, float y, float z)
+{
+	TriMatrix m = identity();
+	m.matrix[0 + 3 * 4] = x;
+	m.matrix[1 + 3 * 4] = y;
+	m.matrix[2 + 3 * 4] = z;
+	return m;
+}
+
+TriMatrix TriMatrix::scale(float x, float y, float z)
+{
+	TriMatrix m = null();
+	m.matrix[0 + 0 * 4] = x;
+	m.matrix[1 + 1 * 4] = y;
+	m.matrix[2 + 2 * 4] = z;
+	m.matrix[3 + 3 * 4] = 1;
+	return m;
+}
+
+TriMatrix TriMatrix::rotate(float angle, float x, float y, float z)
+{
+	float c = cosf(angle);
+	float s = sinf(angle);
+	TriMatrix m = null();
+	m.matrix[0 + 0 * 4] = (x*x*(1.0f - c) + c);
+	m.matrix[0 + 1 * 4] = (x*y*(1.0f - c) - z*s);
+	m.matrix[0 + 2 * 4] = (x*z*(1.0f - c) + y*s);
+	m.matrix[1 + 0 * 4] = (y*x*(1.0f - c) + z*s);
+	m.matrix[1 + 1 * 4] = (y*y*(1.0f - c) + c);
+	m.matrix[1 + 2 * 4] = (y*z*(1.0f - c) - x*s);
+	m.matrix[2 + 0 * 4] = (x*z*(1.0f - c) - y*s);
+	m.matrix[2 + 1 * 4] = (y*z*(1.0f - c) + x*s);
+	m.matrix[2 + 2 * 4] = (z*z*(1.0f - c) + c);
+	m.matrix[3 + 3 * 4] = 1.0f;
+	return m;
+}
+
+TriMatrix TriMatrix::frustum(float left, float right, float bottom, float top, float near, float far)
+{
+	float a = (right + left) / (right - left);
+	float b = (top + bottom) / (top - bottom);
+	float c = -(far + near) / (far - near);
+	float d = -(2.0f * far) / (far - near);
+	TriMatrix m = null();
+	m.matrix[0 + 0 * 4] = 2.0f * near / (right - left);
+	m.matrix[1 + 1 * 4] = 2.0f * near / (top - bottom);
+	m.matrix[0 + 2 * 4] = a;
+	m.matrix[1 + 2 * 4] = b;
+	m.matrix[2 + 2 * 4] = c;
+	m.matrix[2 + 3 * 4] = d;
+	m.matrix[3 + 2 * 4] = -1;
+	return m;
+}
+
+TriMatrix TriMatrix::worldToView()
+{
+	TriMatrix m = null();
+	m.matrix[0 + 0 * 4] = (float)ViewSin;
+	m.matrix[0 + 1 * 4] = (float)-ViewCos;
+	m.matrix[1 + 2 * 4] = 1.0f;
+	m.matrix[2 + 0 * 4] = (float)-ViewCos;
+	m.matrix[2 + 1 * 4] = (float)-ViewSin;
+	m.matrix[3 + 3 * 4] = 1.0f;
+	return m * translate((float)-ViewPos.X, (float)-ViewPos.Y, (float)-ViewPos.Z);
+}
+
+TriMatrix TriMatrix::viewToClip()
+{
+	float near = 5.0f;
+	float far = 65536.0f;
+	float width = (float)(FocalTangent * near);
+	float top = (float)(CenterY / InvZtoScale * near);
+	float bottom = (float)(top - viewheight / InvZtoScale * near);
+	return frustum(-width, width, bottom, top, near, far);
+}
+
+TriMatrix TriMatrix::operator*(const TriMatrix &mult) const
+{
+	TriMatrix result;
+	for (int x = 0; x < 4; x++)
+	{
+		for (int y = 0; y < 4; y++)
+		{
+			result.matrix[x + y * 4] =
+				matrix[0 * 4 + x] * mult.matrix[y * 4 + 0] +
+				matrix[1 * 4 + x] * mult.matrix[y * 4 + 1] +
+				matrix[2 * 4 + x] * mult.matrix[y * 4 + 2] +
+				matrix[3 * 4 + x] * mult.matrix[y * 4 + 3];
+		}
+	}
+	return result;
+}
+
+TriVertex TriMatrix::operator*(TriVertex v) const
+{
+	float vx = matrix[0 * 4 + 0] * v.x + matrix[1 * 4 + 0] * v.y + matrix[2 * 4 + 0] * v.z + matrix[3 * 4 + 0] * v.w;
+	float vy = matrix[0 * 4 + 1] * v.x + matrix[1 * 4 + 1] * v.y + matrix[2 * 4 + 1] * v.z + matrix[3 * 4 + 1] * v.w;
+	float vz = matrix[0 * 4 + 2] * v.x + matrix[1 * 4 + 2] * v.y + matrix[2 * 4 + 2] * v.z + matrix[3 * 4 + 2] * v.w;
+	float vw = matrix[0 * 4 + 3] * v.x + matrix[1 * 4 + 3] * v.y + matrix[2 * 4 + 3] * v.z + matrix[3 * 4 + 3] * v.w;
+	v.x = vx;
+	v.y = vy;
+	v.z = vz;
+	v.w = vw;
+	return v;
+}
diff --git a/src/r_triangle.h b/src/r_triangle.h
new file mode 100644
index 000000000..05cfada98
--- /dev/null
+++ b/src/r_triangle.h
@@ -0,0 +1,109 @@
+/*
+**  Triangle drawers
+**  Copyright (c) 2016 Magnus Norddahl
+**
+**  This software is provided 'as-is', without any express or implied
+**  warranty.  In no event will the authors be held liable for any damages
+**  arising from the use of this software.
+**
+**  Permission is granted to anyone to use this software for any purpose,
+**  including commercial applications, and to alter it and redistribute it
+**  freely, subject to the following restrictions:
+**
+**  1. The origin of this software must not be misrepresented; you must not
+**     claim that you wrote the original software. If you use this software
+**     in a product, an acknowledgment in the product documentation would be
+**     appreciated but is not required.
+**  2. Altered source versions must be plainly marked as such, and must not be
+**     misrepresented as being the original software.
+**  3. This notice may not be removed or altered from any source distribution.
+**
+*/
+
+
+#ifndef __R_TRIANGLE__
+#define __R_TRIANGLE__
+
+#include "r_draw.h"
+
+class FTexture;
+struct ScreenTriangleDrawerArgs;
+
+struct TriVertex
+{
+	TriVertex() { }
+	TriVertex(float x, float y, float z, float w, float u, float v, float light) : x(x), y(y), z(z), w(w) { varying[0] = u; varying[1] = v; varying[2] = light; }
+
+	enum { NumVarying = 3 };
+	float x, y, z, w;
+	float varying[NumVarying];
+};
+
+struct TriMatrix
+{
+	static TriMatrix null();
+	static TriMatrix identity();
+	static TriMatrix translate(float x, float y, float z);
+	static TriMatrix scale(float x, float y, float z);
+	static TriMatrix rotate(float angle, float x, float y, float z);
+	static TriMatrix frustum(float left, float right, float bottom, float top, float near, float far);
+
+	static TriMatrix worldToView(); // Software renderer world to view space transform
+	static TriMatrix viewToClip(); // Software renderer shearing projection
+
+	TriVertex operator*(TriVertex v) const;
+	TriMatrix operator*(const TriMatrix &m) const;
+
+	float matrix[16];
+};
+
+enum class TriangleDrawMode
+{
+	Normal,
+	Fan,
+	Strip
+};
+
+class TriangleDrawer
+{
+public:
+	static void draw(const TriMatrix &objectToClip, const TriVertex *vinput, int vcount, TriangleDrawMode mode, bool ccw, int clipleft, int clipright, const short *cliptop, const short *clipbottom, FTexture *texture);
+	static void fill(const TriMatrix &objectToClip, const TriVertex *vinput, int vcount, TriangleDrawMode mode, bool ccw, int clipleft, int clipright, const short *cliptop, const short *clipbottom, int solidcolor);
+
+private:
+	static TriVertex shade_vertex(const TriMatrix &objectToClip, TriVertex v);
+	static void draw_arrays(const TriMatrix &objectToClip, const TriVertex *vinput, int vcount, TriangleDrawMode mode, bool ccw, int clipleft, int clipright, const short *cliptop, const short *clipbottom, FTexture *texture, int solidcolor, void(*drawfunc)(const ScreenTriangleDrawerArgs *));
+	static void draw_shaded_triangle(const TriVertex *vertices, bool ccw, ScreenTriangleDrawerArgs *args, void(*drawfunc)(const ScreenTriangleDrawerArgs *));
+	static bool cullhalfspace(float clipdistance1, float clipdistance2, float &t1, float &t2);
+	static void clipedge(const TriVertex &v1, const TriVertex &v2, TriVertex *clippedvert, int &numclipvert);
+};
+
+struct ScreenTriangleDrawerArgs
+{
+	uint8_t *dest;
+	int pitch;
+	TriVertex *v1;
+	TriVertex *v2;
+	TriVertex *v3;
+	int clipleft;
+	int clipright;
+	const short *cliptop;
+	const short *clipbottom;
+	const uint8_t *texturePixels;
+	int textureWidth;
+	int textureHeight;
+	int solidcolor;
+};
+
+class ScreenTriangleDrawer
+{
+public:
+	static void draw(const ScreenTriangleDrawerArgs *args);
+	static void fill(const ScreenTriangleDrawerArgs *args);
+
+private:
+	static float gradx(float x0, float y0, float x1, float y1, float x2, float y2, float c0, float c1, float c2);
+	static float grady(float x0, float y0, float x1, float y1, float x2, float y2, float c0, float c1, float c2);
+};
+
+#endif