From f192d7052e9f30f0ba773bf3b07652cd47544ab6 Mon Sep 17 00:00:00 2001
From: aap <aap@papnet.eu>
Date: Mon, 6 Apr 2020 20:32:44 +0200
Subject: [PATCH] finished CCollision

---
 README.md              |  1 -
 src/core/Collision.cpp | 83 +++++++++++++++++++++++++++++++++++++++++-
 src/core/Collision.h   |  1 -
 3 files changed, 81 insertions(+), 4 deletions(-)

diff --git a/README.md b/README.md
index d178f020..e1b1b340 100644
--- a/README.md
+++ b/README.md
@@ -42,7 +42,6 @@ cAudioManager - WIP
 CBoat
 CBrightLights
 CBulletInfo
-CCollision - almost done
 CCullZone - only mobile stuff
 CCullZones - only mobile stuff
 CExplosion
diff --git a/src/core/Collision.cpp b/src/core/Collision.cpp
index 94ef769e..c884f751 100644
--- a/src/core/Collision.cpp
+++ b/src/core/Collision.cpp
@@ -34,8 +34,6 @@ enum Direction
 eLevelName &CCollision::ms_collisionInMemory = *(eLevelName*)0x8F6250;
 CLinkList<CColModel*> &CCollision::ms_colModelCache = *(CLinkList<CColModel*>*)0x95CB58;
 
-WRAPPER bool CCollision::IsStoredPolyStillValidVerticalLine(const CVector &pos, float z, CColPoint &point, CStoredCollPoly *poly) { EAXJMP(0x4105A0); }
-
 void
 CCollision::Init(void)
 {
@@ -926,6 +924,87 @@ CCollision::ProcessVerticalLineTriangle(const CColLine &line,
 	return true;
 }
 
+bool
+CCollision::IsStoredPolyStillValidVerticalLine(const CVector &pos, float z, CColPoint &point, CStoredCollPoly *poly)
+{
+	float t;
+
+	if(!poly->valid)
+		return false;
+
+	// maybe inlined?
+	CColTriangle tri;
+	tri.a = 0;
+	tri.b = 1;
+	tri.c = 2;
+	CColTrianglePlane plane;
+	plane.Set(poly->verts, tri);
+
+	const CVector &va = poly->verts[tri.a];
+	const CVector &vb = poly->verts[tri.b];
+	const CVector &vc = poly->verts[tri.c];
+	CVector p0 = pos;
+	CVector p1(pos.x, pos.y, z);
+
+	// The rest is pretty much CCollision::ProcessLineTriangle
+
+	// if points are on the same side, no collision
+	if(plane.CalcPoint(p0) * plane.CalcPoint(p1) > 0.0f)
+		return poly->valid = false;
+
+	// intersection parameter on line
+	t = -plane.CalcPoint(p0) / DotProduct(p1 - p0, plane.normal);
+	// find point of intersection
+	CVector p = p0 + (p1-p0)*t;
+
+	CVector2D vec1, vec2, vec3, vect;
+	switch(plane.dir){
+	case DIR_X_POS:
+		vec1.x = va.y; vec1.y = va.z;
+		vec2.x = vc.y; vec2.y = vc.z;
+		vec3.x = vb.y; vec3.y = vb.z;
+		vect.x = p.y; vect.y = p.z;
+		break;
+	case DIR_X_NEG:
+		vec1.x = va.y; vec1.y = va.z;
+		vec2.x = vb.y; vec2.y = vb.z;
+		vec3.x = vc.y; vec3.y = vc.z;
+		vect.x = p.y; vect.y = p.z;
+		break;
+	case DIR_Y_POS:
+		vec1.x = va.z; vec1.y = va.x;
+		vec2.x = vc.z; vec2.y = vc.x;
+		vec3.x = vb.z; vec3.y = vb.x;
+		vect.x = p.z; vect.y = p.x;
+		break;
+	case DIR_Y_NEG:
+		vec1.x = va.z; vec1.y = va.x;
+		vec2.x = vb.z; vec2.y = vb.x;
+		vec3.x = vc.z; vec3.y = vc.x;
+		vect.x = p.z; vect.y = p.x;
+		break;
+	case DIR_Z_POS:
+		vec1.x = va.x; vec1.y = va.y;
+		vec2.x = vc.x; vec2.y = vc.y;
+		vec3.x = vb.x; vec3.y = vb.y;
+		vect.x = p.x; vect.y = p.y;
+		break;
+	case DIR_Z_NEG:
+		vec1.x = va.x; vec1.y = va.y;
+		vec2.x = vb.x; vec2.y = vb.y;
+		vec3.x = vc.x; vec3.y = vc.y;
+		vect.x = p.x; vect.y = p.y;
+		break;
+	default:
+		assert(0);
+	}
+	if(CrossProduct2D(vec2-vec1, vect-vec1) < 0.0f) return poly->valid = false;
+	if(CrossProduct2D(vec3-vec1, vect-vec1) > 0.0f) return poly->valid = false;
+	if(CrossProduct2D(vec3-vec2, vect-vec2) < 0.0f) return poly->valid = false;
+	point.point = p;
+	return poly->valid = true;
+}
+
 bool
 CCollision::ProcessLineTriangle(const CColLine &line ,
 	const CVector *verts, const CColTriangle &tri, const CColTrianglePlane &plane,
diff --git a/src/core/Collision.h b/src/core/Collision.h
index 429fc17f..1cbd1690 100644
--- a/src/core/Collision.h
+++ b/src/core/Collision.h
@@ -144,7 +144,6 @@ public:
 	static bool ProcessLineOfSight(const CColLine &line, const CMatrix &matrix, CColModel &model, CColPoint &point, float &mindist, bool ignoreSeeThrough);
 	static bool ProcessVerticalLine(const CColLine &line, const CMatrix &matrix, CColModel &model, CColPoint &point, float &mindist, bool ignoreSeeThrough, CStoredCollPoly *poly);
 	static int32 ProcessColModels(const CMatrix &matrixA, CColModel &modelA, const CMatrix &matrixB, CColModel &modelB, CColPoint *spherepoints, CColPoint *linepoints, float *linedists);
-	// TODO:
 	static bool IsStoredPolyStillValidVerticalLine(const CVector &pos, float z, CColPoint &point, CStoredCollPoly *poly);
 
 	static float DistToLine(const CVector *l0, const CVector *l1, const CVector *point);