From dfed20701a168d431a7c1bc72a406b2128012e5b Mon Sep 17 00:00:00 2001
From: "Unknown W. Brackets" <checkins@unknownbrackets.org>
Date: Sat, 15 Apr 2017 19:52:17 -0700
Subject: [PATCH] SoftGPU: Correct negative coord handling.

Fixes #5159 - we need this signed to handle negative values properly.
---
 GPU/Software/Clipper.cpp       |  8 ++++----
 GPU/Software/Rasterizer.cpp    |  4 ++--
 GPU/Software/TransformUnit.cpp |  4 ++--
 GPU/Software/TransformUnit.h   | 11 +++++------
 4 files changed, 13 insertions(+), 14 deletions(-)

diff --git a/GPU/Software/Clipper.cpp b/GPU/Software/Clipper.cpp
index f0bbacdd71..818113efdb 100644
--- a/GPU/Software/Clipper.cpp
+++ b/GPU/Software/Clipper.cpp
@@ -128,10 +128,10 @@ static inline int CalcClipMask(const ClipCoords& v)
 }
 
 static void RotateUVThrough(const VertexData &tl, const VertexData &br, VertexData &tr, VertexData &bl) {
-	const fixed16 x1 = tl.screenpos.x;
-	const fixed16 x2 = br.screenpos.x;
-	const fixed16 y1 = tl.screenpos.y;
-	const fixed16 y2 = br.screenpos.y;
+	const int x1 = tl.screenpos.x;
+	const int x2 = br.screenpos.x;
+	const int y1 = tl.screenpos.y;
+	const int y2 = br.screenpos.y;
 
 	if ((x1 < x2 && y1 > y2) || (x1 > x2 && y1 < y2)) {
 		std::swap(bl.texturecoords, tr.texturecoords);
diff --git a/GPU/Software/Rasterizer.cpp b/GPU/Software/Rasterizer.cpp
index 9d190a8cfb..a88ec11a98 100644
--- a/GPU/Software/Rasterizer.cpp
+++ b/GPU/Software/Rasterizer.cpp
@@ -509,14 +509,14 @@ static inline bool DepthTestPassed(int x, int y, u16 z)
 	}
 }
 
-static inline bool IsRightSideOrFlatBottomLine(const Vec2<fixed16>& vertex, const Vec2<fixed16>& line1, const Vec2<fixed16>& line2)
+static inline bool IsRightSideOrFlatBottomLine(const Vec2<int>& vertex, const Vec2<int>& line1, const Vec2<int>& line2)
 {
 	if (line1.y == line2.y) {
 		// just check if vertex is above us => bottom line parallel to x-axis
 		return vertex.y < line1.y;
 	} else {
 		// check if vertex is on our left => right side
-		return vertex.x < line1.x + ((int)line2.x - (int)line1.x) * ((int)vertex.y - (int)line1.y) / ((int)line2.y - (int)line1.y);
+		return vertex.x < line1.x + (line2.x - line1.x) * (vertex.y - line1.y) / (line2.y - line1.y);
 	}
 }
 
diff --git a/GPU/Software/TransformUnit.cpp b/GPU/Software/TransformUnit.cpp
index 5fd39c6974..06f2208d24 100644
--- a/GPU/Software/TransformUnit.cpp
+++ b/GPU/Software/TransformUnit.cpp
@@ -191,8 +191,8 @@ VertexData TransformUnit::ReadVertex(VertexReader& vreader)
 
 		Lighting::Process(vertex, vreader.hasColor0());
 	} else {
-		vertex.screenpos.x = (u32)pos[0] * 16 + gstate.getOffsetX16();
-		vertex.screenpos.y = (u32)pos[1] * 16 + gstate.getOffsetY16();
+		vertex.screenpos.x = (int)(pos[0] * 16) + gstate.getOffsetX16();
+		vertex.screenpos.y = (int)(pos[1] * 16) + gstate.getOffsetY16();
 		vertex.screenpos.z = pos[2];
 		vertex.clippos.w = 1.f;
 		vertex.fogdepth = 1.f;
diff --git a/GPU/Software/TransformUnit.h b/GPU/Software/TransformUnit.h
index 84ca3a2cdb..b0b77833e1 100644
--- a/GPU/Software/TransformUnit.h
+++ b/GPU/Software/TransformUnit.h
@@ -23,7 +23,6 @@
 
 using namespace Math3D;
 
-typedef u16 fixed16;
 typedef u16 u10; // TODO: erm... :/
 
 typedef Vec3<float> ModelCoords;
@@ -36,17 +35,17 @@ struct SplinePatch;
 struct ScreenCoords
 {
 	ScreenCoords() {}
-	ScreenCoords(fixed16 x, fixed16 y, u16 z) : x(x), y(y), z(z) {}
+	ScreenCoords(int x, int y, u16 z) : x(x), y(y), z(z) {}
 
-	fixed16 x;
-	fixed16 y;
+	int x;
+	int y;
 	u16 z;
 
-	Vec2<fixed16> xy() const { return Vec2<fixed16>(x, y); }
+	Vec2<int> xy() const { return Vec2<int>(x, y); }
 
 	ScreenCoords operator * (const float t) const
 	{
-		return ScreenCoords((fixed16)(x * t), (fixed16)(y * t), (u16)(z * t));
+		return ScreenCoords((int)(x * t), (int)(y * t), (u16)(z * t));
 	}
 
 	ScreenCoords operator / (const int t) const