Add portal plane clipping

src/r_poly.cpp

@@ -44,7 +44,7 @@ void RenderPolyScene::Render()
 	ClearBuffers();
 	SetSceneViewport();
 	SetupPerspectiveMatrix();
-	MainPortal.SetViewpoint(WorldToClip, GetNextStencilValue());
+	MainPortal.SetViewpoint(WorldToClip, Vec4f(0.0f), GetNextStencilValue());
 	MainPortal.Render(0);
 	Skydome.Render(WorldToClip);
 	MainPortal.RenderTranslucent(0);

src/r_poly_cull.cpp

@@ -28,11 +28,12 @@
 #include "r_poly_cull.h"
 #include "r_poly.h"
 
-void PolyCull::CullScene(const TriMatrix &worldToClip)
+void PolyCull::CullScene(const TriMatrix &worldToClip, const Vec4f &portalClipPlane)
 {
 	ClearSolidSegments();
 	PvsSectors.clear();
 	frustumPlanes = FrustumPlanes(worldToClip);
+	PortalClipPlane = portalClipPlane;
 
 	// Cull front to back
 	MaxCeilingHeight = 0.0;
@@ -174,6 +175,11 @@ bool PolyCull::CheckBBox(float *bspcoord)
 	if (result == IntersectionTest::outside)
 		return false;
 
+	// Skip if its in front of the portal:
+
+	if (PortalClipPlane != Vec4f(0.0f) && IntersectionTest::plane_aabb(PortalClipPlane, aabb) == IntersectionTest::outside)
+		return false;
+
 	// Occlusion test using solid segments:
 
 	static const int lines[4][4] =
@@ -219,6 +225,10 @@ bool PolyCull::GetSegmentRangeForLine(double x1, double y1, double x2, double y2
 {
 	double znear = 5.0;
 
+	// Cull if entirely behind the portal clip plane (tbd: should we clip the segment?)
+	if (Vec4f::dot(PortalClipPlane, Vec4f((float)x1, (float)y1, 0.0f, 1.0f)) < 0.0f && Vec4f::dot(PortalClipPlane, Vec4f((float)x2, (float)y2, 0.0f, 1.0f)) < 0.0f)
+		return false;
+
 	// Transform to 2D view space:
 	x1 = x1 - ViewPos.X;
 	y1 = y1 - ViewPos.Y;

src/r_poly_cull.h

@@ -28,7 +28,7 @@
 class PolyCull
 {
 public:
-	void CullScene(const TriMatrix &worldToClip);
+	void CullScene(const TriMatrix &worldToClip, const Vec4f &portalClipPlane);
 
 	bool GetSegmentRangeForLine(double x1, double y1, double x2, double y2, int &sx1, int &sx2) const;
 	void MarkSegmentCulled(int x1, int x2);
@@ -59,4 +59,5 @@ private:
 	const int SolidCullScale = 3000;
 
 	FrustumPlanes frustumPlanes;
+	Vec4f PortalClipPlane;
 };

src/r_poly_intersection.h

@@ -26,6 +26,8 @@
 #include <algorithm>
 #include <cmath>
 
+class Vec3f;
+
 class Vec4f
 {
 public:
@@ -33,6 +35,7 @@ public:
 	Vec4f(const Vec4f &) = default;
 	Vec4f(float x, float y, float z, float w) : x(x), y(y), z(z), w(w) { }
 	Vec4f(float v) : x(v), y(v), z(v), w(v) { }
+	Vec4f(const Vec3f &xyz, float w);
 
 	static float dot(const Vec4f &a, const Vec4f &b) { return a.x * b.x + a.y * b.y + a.z * b.z + a.w * b.w; }
 	static float dot3(const Vec4f &a, const Vec4f &b) { return a.x * b.x + a.y * b.y + a.z * b.z; }
@@ -51,6 +54,9 @@ public:
 	float x, y, z, w;
 };
 
+inline bool operator==(const Vec4f &a, const Vec4f &b) { return a.x == b.x && a.y == b.y && a.z == b.z && a.w == b.w; }
+inline bool operator!=(const Vec4f &a, const Vec4f &b) { return a.x != b.x || a.y != b.y || a.z != b.z || a.w == b.w; }
+
 class Vec3f
 {
 public:
@@ -75,6 +81,9 @@ public:
 	float x, y, z;
 };
 
+inline bool operator==(const Vec3f &a, const Vec3f &b) { return a.x == b.x && a.y == b.y && a.z == b.z; }
+inline bool operator!=(const Vec3f &a, const Vec3f &b) { return a.x != b.x || a.y != b.y || a.z != b.z; }
+
 inline Vec3f operator+(const Vec3f &a, const Vec3f &b) { return Vec3f(a.x + b.x, a.y + b.y, a.z + b.z); }
 inline Vec3f operator-(const Vec3f &a, const Vec3f &b) { return Vec3f(a.x - b.x, a.y - b.y, a.z - b.z); }
 inline Vec3f operator*(const Vec3f &a, const Vec3f &b) { return Vec3f(a.x * b.x, a.y * b.y, a.z * b.z); }
@@ -90,6 +99,8 @@ inline Vec3f operator-(float a, const Vec3f &b) { return Vec3f(a - b.x, a - b.y,
 inline Vec3f operator*(float a, const Vec3f &b) { return Vec3f(a * b.x, a * b.y, a * b.z); }
 inline Vec3f operator/(float a, const Vec3f &b) { return Vec3f(a / b.x, a / b.y, a / b.z); }
 
+inline Vec4f::Vec4f(const Vec3f &xyz, float w) : x(xyz.x), y(xyz.y), z(xyz.z), w(w) { }
+
 typedef TriMatrix Mat4f;
 
 class AxisAlignedBoundingBox

src/r_poly_portal.cpp

@@ -45,16 +45,17 @@ RenderPolyPortal::~RenderPolyPortal()
 {
 }
 
-void RenderPolyPortal::SetViewpoint(const TriMatrix &worldToClip, uint32_t stencilValue)
+void RenderPolyPortal::SetViewpoint(const TriMatrix &worldToClip, const Vec4f &portalPlane, uint32_t stencilValue)
 {
 	WorldToClip = worldToClip;
 	StencilValue = stencilValue;
+	PortalPlane = portalPlane;
 }
 
 void RenderPolyPortal::Render(int portalDepth)
 {
 	ClearBuffers();
-	Cull.CullScene(WorldToClip);
+	Cull.CullScene(WorldToClip, PortalPlane);
 	RenderSectors();
 	RenderPortals(portalDepth);
 }
@@ -340,7 +341,7 @@ void PolyDrawSectorPortal::Render(int portalDepth)
 		TriMatrix::translate((float)-ViewPos.X, (float)-ViewPos.Y, (float)-ViewPos.Z);
 	TriMatrix worldToClip = TriMatrix::perspective(fovy, ratio, 5.0f, 65535.0f) * worldToView;
 
-	RenderPortal.SetViewpoint(worldToClip, StencilValue);
+	RenderPortal.SetViewpoint(worldToClip, Vec4f(0.0f), StencilValue);
 	RenderPortal.Render(portalDepth);
 	
 	RestoreGlobals();
@@ -440,7 +441,14 @@ void PolyDrawLinePortal::Render(int portalDepth)
 		TriMatrix::translate((float)-ViewPos.X, (float)-ViewPos.Y, (float)-ViewPos.Z);
 	TriMatrix worldToClip = TriMatrix::perspective(fovy, ratio, 5.0f, 65535.0f) * worldToView;
 
-	RenderPortal.SetViewpoint(worldToClip, StencilValue);
+	// Calculate plane clipping
+	DVector2 planePos = Portal->mDestination->v1->fPos();
+	DVector2 planeNormal = (Portal->mDestination->v2->fPos() - Portal->mDestination->v1->fPos()).Rotated90CW();
+	planeNormal.MakeUnit();
+	double planeD = -(planeNormal | (planePos + planeNormal * 5.0));
+	Vec4f portalPlane((float)planeNormal.X, (float)planeNormal.Y, 0.0f, (float)planeD);
+
+	RenderPortal.SetViewpoint(worldToClip, portalPlane, StencilValue);
 	RenderPortal.Render(portalDepth);
 
 	RestoreGlobals();

src/r_poly_portal.h

@@ -83,7 +83,7 @@ class RenderPolyPortal
 public:
 	RenderPolyPortal();
 	~RenderPolyPortal();
-	void SetViewpoint(const TriMatrix &worldToClip, uint32_t stencilValue);
+	void SetViewpoint(const TriMatrix &worldToClip, const Vec4f &portalPlane, uint32_t stencilValue);
 	void Render(int portalDepth);
 	void RenderTranslucent(int portalDepth);
 
@@ -99,6 +99,7 @@ private:
 	SpriteRange GetSpritesForSector(sector_t *sector);
 
 	TriMatrix WorldToClip;
+	Vec4f PortalPlane;
 	uint32_t StencilValue = 0;
 	PolyCull Cull;
 	uint32_t NextSubsectorDepth = 0;