From f8fe689a81f906d1b91bb3220acde2a4ecb14c5b Mon Sep 17 00:00:00 2001
From: Daniel Baumann <daniel.baumann@progress-linux.org>
Date: Mon, 6 May 2024 05:01:46 +0200
Subject: Adding upstream version 6.0.4-dfsg.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
---
 .../SharedOpenGL/crserverlib/server_clip.c         | 588 +++++++++++++++++++++
 1 file changed, 588 insertions(+)
 create mode 100644 src/VBox/HostServices/SharedOpenGL/crserverlib/server_clip.c

(limited to 'src/VBox/HostServices/SharedOpenGL/crserverlib/server_clip.c')

diff --git a/src/VBox/HostServices/SharedOpenGL/crserverlib/server_clip.c b/src/VBox/HostServices/SharedOpenGL/crserverlib/server_clip.c
new file mode 100644
index 00000000..03143b0d
--- /dev/null
+++ b/src/VBox/HostServices/SharedOpenGL/crserverlib/server_clip.c
@@ -0,0 +1,588 @@
+/* Copyright (c) 2001, Stanford University
+ * All rights reserved
+ *
+ * See the file LICENSE.txt for information on redistributing this software.
+ */
+
+/*
+ * This code contributed by Karl Rasche <rkarl@vr.clemson.edu>
+ */
+
+
+#include <math.h>
+
+#include "cr_server.h"
+#include "cr_mem.h"
+#include "server.h"
+
+
+static void
+__find_intersection(double *s, double *e, double *clp, double *clp_next,
+										double *intr)
+{
+	double v1[2], v2[2];
+	double A, B, T;
+
+	v1[0] = e[0] - s[0];
+	v1[1] = e[1] - s[1];
+	v2[0] = clp_next[0] - clp[0];
+	v2[1] = clp_next[1] - clp[1];
+	
+	if ((v1[1]) && (v2[0]))
+	{
+		A =  (clp[1]-s[1])/v1[1] + (v2[1]/v1[1])*(s[0]-clp[0])/v2[0];
+		B = 1.-(v2[1]/v1[1])*(v1[0]/v2[0]);
+		if (B)
+			T = A/B;
+		else
+		{
+			T = 0;
+		}
+
+		intr[0] = s[0]+T*v1[0];
+		intr[1] = s[1]+T*v1[1];
+	}
+	else
+	if (v1[1])
+	{
+		/* clp -> clp_next is vertical */
+		T = (clp[0]-s[0])/v1[0];
+
+		intr[0] = s[0]+T*v1[0];
+		intr[1] = s[1]+T*v1[1];
+	}
+	else
+	{
+		/* s -> e is horizontal */
+		T = (s[1]-clp[1])/v2[1];
+
+		intr[0] = clp[0]+T*v2[0];
+		intr[1] = clp[1]+T*v2[1];
+	}
+
+}
+
+static void
+ __clip_one_side(double *poly, int npnts, double *clp, double *clp_next,
+								 double *norm, 
+								 double **new_poly_in, int *new_npnts_in,
+								 double **new_poly_out, int *new_npnts_out)
+{
+	int a, sin, ein;
+	double *s, *e, intr[2]; 
+	
+	*new_poly_in  = (double *)crAlloc(2*npnts*2*sizeof(double));
+	*new_npnts_in = 0;
+
+	*new_poly_out  = (double *)crAlloc(2*npnts*2*sizeof(double));
+	*new_npnts_out = 0;
+
+	s = poly;
+
+	for (a=0; a<npnts; a++)
+	{
+		e = poly+2*((a+1)%npnts);
+
+		if (((e[0]-clp[0])*norm[0]) + ((e[1]-clp[1])*norm[1]) >= 0)
+			ein = 0;
+		else
+			ein = 1;
+
+		if (((s[0]-clp[0])*norm[0]) + ((s[1]-clp[1])*norm[1]) >= 0)
+			sin = 0;
+		else
+			sin = 1;
+	
+		if (sin && ein)
+		{
+			/* case 1: */
+			crMemcpy(*new_poly_in+2*(*new_npnts_in), e, 2*sizeof(double));
+			(*new_npnts_in)++;
+		}
+		else
+		if (sin && (!ein))
+		{
+			/* case 2: */
+
+			__find_intersection(s, e, clp, clp_next, intr);
+
+			crMemcpy(*new_poly_in+2*(*new_npnts_in), intr, 2*sizeof(double));
+			(*new_npnts_in)++;
+
+			crMemcpy(*new_poly_out+2*(*new_npnts_out), intr, 2*sizeof(double));
+			(*new_npnts_out)++;
+			crMemcpy(*new_poly_out+2*(*new_npnts_out), e, 2*sizeof(double));
+			(*new_npnts_out)++;
+		}
+		else
+		if ((!sin) && ein)
+		{
+			/* case 4: */
+			__find_intersection(s, e, clp, clp_next, intr);
+
+			crMemcpy((*new_poly_in)+2*(*new_npnts_in), intr, 2*sizeof(double));
+			(*new_npnts_in)++;
+			crMemcpy((*new_poly_in)+2*(*new_npnts_in), e, 2*sizeof(double));
+			(*new_npnts_in)++;
+
+			crMemcpy(*new_poly_out+2*(*new_npnts_out), intr, 2*sizeof(double));
+			(*new_npnts_out)++;
+		}
+		else
+		{
+			crMemcpy(*new_poly_out+2*(*new_npnts_out), e, 2*sizeof(double));
+			(*new_npnts_out)++;
+		}
+
+		s =  e;
+	}
+}
+
+/* 
+ * Sutherland/Hodgman clipping for interior & exterior regions. 
+ * length_of((*new_vert_out)[a]) == nclip_to_vert
+ */
+static void
+__clip(double *poly, int nvert, double *clip_to_poly, int nclip_to_vert,
+			 double **new_vert_in, int *nnew_vert_in,
+			 double ***new_vert_out, int **nnew_vert_out)
+{
+	int a, side, *nout;
+	double *clip_normals, *s, *e, *n, *new_vert_src; 
+	double *norm, *clp, *clp_next;
+ 	double **out;
+	
+	*new_vert_out = (double **)crAlloc(nclip_to_vert*sizeof(double *));
+	*nnew_vert_out = (int *)crAlloc(nclip_to_vert*sizeof(int));
+
+	/* 
+	 * First, compute normals for the clip poly. This 
+	 * breaks for multiple (3+) adjacent colinear vertices
+ 	 */
+	clip_normals = (double *)crAlloc(nclip_to_vert*2*sizeof(double));
+	for (a=0; a<nclip_to_vert; a++)
+	{
+		s = clip_to_poly+2*a;
+		e = clip_to_poly+2*((a+1)%nclip_to_vert);
+		n = clip_to_poly+2*((a+2)%nclip_to_vert);
+
+		norm = clip_normals+2*a;
+		norm[0]   = e[1]-s[1];
+		norm[1] = -1*(e[0]-s[0]);
+		
+		/* 
+		 * if dot(norm, n-e) > 0), the normals are backwards,
+		 * 	assuming the clip region is convex 
+		 */ 
+		if (norm[0]*(n[0]-e[0]) + norm[1]*(n[1]-e[1]) > 0)
+		{
+			norm[0] *= -1;
+			norm[1] *= -1;
+		}
+	}
+
+	new_vert_src  = (double *)crAlloc(nvert*nclip_to_vert*2*sizeof(double));
+	crMemcpy(new_vert_src, poly, 2*nvert*sizeof(double));
+
+	for (side=0; side<nclip_to_vert; side++)
+	{
+		clp      = clip_to_poly+2*side;
+		clp_next = clip_to_poly+2*((side+1)%nclip_to_vert);
+		norm = clip_normals+2*side;
+		*nnew_vert_in = 0;
+
+		nout = (*nnew_vert_out)+side;
+		out  = (*new_vert_out)+side;
+
+	 	__clip_one_side(new_vert_src, nvert, clp, clp_next, norm,
+				new_vert_in, nnew_vert_in, 
+				out, nout);
+
+		crMemcpy(new_vert_src, (*new_vert_in), 2*(*nnew_vert_in)*sizeof(double));
+		if (side != nclip_to_vert-1)
+			crFree(*new_vert_in);
+		nvert = *nnew_vert_in;
+	}
+}
+
+/* 
+ * Given a bitmap and a group of 'base' polygons [the quads we are testing],
+ * perform the unions and differences specified by the map and return
+ * the resulting geometry
+ */
+static void
+__execute_combination(CRPoly **base, int n, int *mask, CRPoly **head)
+{
+	int a, b, got_intr;
+	int nin, *nout, last;
+	double *in, **out;
+	CRPoly *intr, *diff, *p;
+
+	*head = NULL;
+
+	intr = (CRPoly *)crAlloc(sizeof(CRPoly));
+	intr->next = NULL;
+
+	got_intr = 0;
+
+	/* first, intersect the first 2 polys marked */
+	for (a=0; a<n; a++)
+		if (mask[a]) break;
+	for (b=a+1; b<n; b++)
+		if (mask[b]) break;
+
+	__clip(base[a]->points, base[a]->npoints, 
+				base[b]->points, base[b]->npoints,
+				&in, &nin, &out, &nout);
+	last = b;
+
+	crFree (nout);
+	for (a=0; a<base[last]->npoints; a++)
+		if (out[a])
+			crFree(out[a]);
+	crFree(out);
+					
+
+	if (nin)
+	{
+		intr->npoints = nin;
+		intr->points = in;
+		got_intr = 1;
+	}
+
+	while (1)
+	{
+		for (a=last+1; a<n; a++)
+			if (mask[a]) break;
+
+		if (a == n) break;
+
+		if (got_intr)
+		{
+			__clip(base[a]->points, base[a]->npoints, 
+					intr->points, intr->npoints,
+					&in, &nin, &out, &nout);
+
+			crFree (nout);
+			for (b=0; b<intr->npoints; b++)
+				if (out[b])
+					crFree(out[b]);
+			crFree(out);
+
+			if (nin)
+			{
+				intr->npoints = nin;
+				intr->points = in;
+			}
+			else
+			{
+				got_intr = 0;
+				break;
+			}
+		}
+		else
+		{
+			__clip(base[a]->points, base[a]->npoints, 
+					base[last]->points, base[last]->npoints,
+					&in, &nin, &out, &nout);
+			
+			crFree (nout);
+			for (b=0; b<base[last]->npoints; b++)
+			{
+				if (out[b])
+					crFree(out[b]);
+			}
+			crFree(out);
+
+
+			if (nin)
+			{
+				intr->npoints = nin;
+				intr->points = in;
+				got_intr = 1;
+			}
+		}
+
+		last = a;
+		if (a == n) break;
+	}
+
+	/* can't subtract something from nothing! */
+	if (got_intr)
+		*head = intr;
+	else
+		return;
+	
+	/* find the first item to subtract */
+	for (a=0; a<n; a++)
+		if (!mask[a]) break;
+
+	if (a == n) return;
+	last = a;
+
+	/* and subtract it */
+	diff = NULL;
+	__clip(intr->points, intr->npoints,
+				base[last]->points, base[last]->npoints, 
+				&in, &nin, &out, &nout);
+
+	crFree(in);
+
+	for (a=0; a<base[last]->npoints; a++)	
+	{
+		if (!nout[a]) continue;
+
+		p = (CRPoly *)crAlloc(sizeof(CRPoly));
+		p->npoints = nout[a];
+		p->points  = out[a];
+		p->next = diff;
+		diff = p;
+	}
+	*head = diff;
+
+	while (1)
+	{
+		intr = diff;
+		diff = NULL;
+
+		for (a=last+1; a<n; a++)
+			if (!mask[a]) break;
+		if (a == n) return;
+
+		last = a;
+
+		/* subtract mask[a] from everything in intr and
+		 * plop it into diff */
+		while (intr)
+		{
+			__clip(intr->points, intr->npoints,
+				base[last]->points, base[last]->npoints, 
+				&in, &nin, &out, &nout);
+
+			crFree(in);
+
+			for (a=0; a<base[last]->npoints; a++)	
+			{
+				if (!nout[a]) continue;
+
+				p = (CRPoly *)crAlloc(sizeof(CRPoly));
+				p->npoints = nout[a];
+				p->points  = out[a];
+				p->next = diff;
+				diff = p;
+			}
+
+			intr = intr->next;
+		}
+
+		*head = diff;
+	}	
+
+}
+
+/*
+ * Here we generate all valid bitmaps to represent union/difference
+ * combinations. Each bitmap is N elements long, where N is the 
+ * number of polys [quads] that we are testing for overlap
+ */
+static void
+__generate_masks(int n, int ***mask, int *nmasks)
+{
+	int a, b, c, d, e;
+	int i, idx, isec_size, add;
+
+	*mask = (int **)crAlloc((unsigned int)pow(2, n)*sizeof(int));
+	for (a=0; a<pow(2, n); a++)
+		(*mask)[a] = (int *)crAlloc(n*sizeof(int));
+
+	/* compute combinations */
+	idx = 0;
+	for (isec_size=1; isec_size<n; isec_size++)
+	{
+		for (a=0; a<n; a++)
+		{
+			for (b=a+1; b<n; b++)
+			{
+				crMemset((*mask)[idx], 0, n*sizeof(int));
+				(*mask)[idx][a] = 1;
+
+				add = 1;
+				for (c=0; c<isec_size; c++)
+				{
+					i = (b+c) % n;
+					if (i == a) add = 0;
+						
+					(*mask)[idx][i] = 1;	
+				}
+
+				/* dup check */
+				if ((add) && (idx))
+				{
+					for (d=0; d<idx; d++)
+					{
+						add = 0;
+						for (e=0; e<n; e++)
+						{
+							if ((*mask)[idx][e] != (*mask)[d][e]) 
+								add = 1;
+						}
+
+						if (!add)
+							break;
+					}
+				}
+
+				if (add) 
+					idx++;
+			}
+		}
+	}
+
+	*nmasks = idx;
+}
+
+/* 
+ * To compute the overlap between a series of quads (This should work 
+ * for n-gons, but we'll only need quads..), first generate a series of 
+ * bitmaps that represent which elements to union together, and which
+ * to difference. This goes into 'mask'. We then evaluate each bitmap with
+ * Sutherland-Hodgman clipping to find the interior (union) and exterior
+ * (difference) regions.
+ *
+ * In the map, 1 == union, 0 == difference
+ *
+ * (*res)[a] is the head of a poly list for all the polys that convert 
+ * regions of overlap between a+1 polys ((*res)[0] == NULL)
+ */ 
+void
+crComputeOverlapGeom(double *quads, int nquad, CRPoly ***res)
+{
+	int a, b, idx, isec_size, **mask;
+	CRPoly *p, *next, **base;
+	
+	base = (CRPoly **)crAlloc(nquad*sizeof(CRPoly *));
+	for (a=0; a<nquad; a++)
+	{
+		p = (CRPoly *)crAlloc(sizeof(CRPoly));
+		p->npoints = 4;
+		p->points  = (double *)crAlloc(8*sizeof(double));
+		for (b=0; b<8; b++)
+		{
+			p->points[b] = quads[8*a+b];
+		}
+		p->next = NULL;
+		base[a] = p;
+	}
+	
+	*res = (CRPoly **)crAlloc(nquad*sizeof(CRPoly *));
+	for (a=0; a<nquad; a++)
+		(*res)[a] = NULL;
+	
+	__generate_masks(nquad, &mask, &idx);
+
+	for (a=0; a<idx; a++)
+	{
+		isec_size = 0;
+		for (b=0; b<nquad; b++)
+			if (mask[a][b]) isec_size++;
+		isec_size--;
+
+		__execute_combination(base, nquad, mask[a], &p);
+	
+		while (p)
+		{
+			next = p->next;
+			
+			p->next = (*res)[isec_size];
+			(*res)[isec_size] = p;
+			
+			p = next;
+		}
+	}
+
+	for (a=0; a<nquad; a++)
+	{
+		crFree(base[a]->points);
+		crFree(base[a]);
+	}
+	crFree(base);		
+
+}
+
+/*
+ * This is similar to ComputeOverlapGeom above, but for "knockout" 
+ * edge blending. 
+ *
+ * my_quad_idx is an index of quads indicating which display tile 
+ * we are computing geometry for. From this, we either generate
+ * geometry, or not, such that all geometry can be drawn in black 
+ * and only one tile will show through the blend as non-black.
+ *
+ * To add a combination to our set of geom, we must test that:
+ * 		+ mask[a][my_quad_idx] is set
+ * 		+ mask[a][my_quad_idx] is not the first element set in
+ * 			mask[a].
+ * If these conditions hold, execute mask[a] and draw the resulting
+ * geometry in black
+ *
+ * Unlike ComputeOverlapGeom, res is just a list of polys to draw in black
+ */ 	
+void
+crComputeKnockoutGeom(double *quads, int nquad, int my_quad_idx, CRPoly **res)
+{
+	int a, b, idx, first, **mask;
+	CRPoly *p, *next, **base;
+	
+	base = (CRPoly **) crAlloc(nquad*sizeof(CRPoly *));
+	for (a=0; a<nquad; a++)
+	{
+		p = (CRPoly *) crAlloc(sizeof(CRPoly));
+		p->npoints = 4;
+		p->points  = (double *) crAlloc(8*sizeof(double));
+		for (b=0; b<8; b++)
+		{
+			p->points[b] = quads[8*a+b];
+		}
+		p->next = NULL;
+		base[a] = p;
+	}
+	
+	(*res) = NULL;
+	
+	__generate_masks(nquad, &mask, &idx);
+
+	for (a=0; a<idx; a++)
+	{
+		/* test for above conditions */
+		if (!mask[a][my_quad_idx]) continue;	
+
+		first = -1;
+		for (b=0; b<nquad; b++)
+			if (mask[a][b]) 
+			{
+				first = b;
+				break;
+			}
+		if (first == my_quad_idx) continue;
+
+
+		__execute_combination(base, nquad, mask[a], &p);
+	
+		while (p)
+		{
+			next = p->next;
+			
+			p->next = *res;
+			*res = p;
+			
+			p = next;
+		}
+	}
+
+	for (a=0; a<nquad; a++)
+	{
+		crFree(base[a]->points);
+		crFree(base[a]);
+	}
+	crFree(base);		
+}
-- 
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