code cleanup: remove unused structs and also some style cleanup.

1 files changed, 383 insertions, 395 deletions

diff --git a/intern/raskter/raskter.c b/intern/raskter/raskter.c
index af58c2aca4d..2fe9ac61a48 100644
--- a/intern/raskter/raskter.c
+++ b/intern/raskter/raskter.c
@@ -24,6 +24,7 @@
  *
  * ***** END GPL LICENSE BLOCK *****
  */
+
 /** \file raskter.c
  *  \ingroup RASKTER
  */
@@ -36,60 +37,36 @@
 #define MAX2(x, y)               ( (x) > (y) ? (x) : (y) )
 #define ABS(a)                   ( (a) < 0 ? (-(a)) : (a) )
 
-struct poly_vert {
-    int x;
-    int y;
-};
-
-struct scan_line {
-    int xstart;
-    int xend;
-};
-
-struct scan_line_batch {
-    int num;
-    int ystart;
-    struct scan_line *slines;
-};
-
-struct e_status {
-    int x;
-    int ybeg;
-    int xshift;
-    int xdir;
-    int drift;
-    int drift_inc;
-    int drift_dec;
-    int num;
-    struct e_status *e_next;
+struct PolyVert {
+	int x;
+	int y;
 };
 
-struct r_buffer_stats {
-    float *buf;
-    int sizex;
-    int sizey;
-    int ymin;
-    int ymax;
-    int xmin;
-    int xmax;
+struct e_Status {
+	int x;
+	int ybeg;
+	int xshift;
+	int xdir;
+	int drift;
+	int drift_inc;
+	int drift_dec;
+	int num;
+	struct e_Status *e_next;
 };
 
-struct r_fill_context {
-    struct e_status *all_edges, *possible_edges;
-    struct r_buffer_stats rb;
-    struct scan_line *bounds;
-    void *kdo;  //only used with kd tree
-    void *kdi;  //only used with kd tree
-    int *bound_indexes;
-    int bounds_length;
+struct r_BufferStats {
+	float *buf;
+	int sizex;
+	int sizey;
+	int ymin;
+	int ymax;
+	int xmin;
+	int xmax;
 };
 
-struct layer_init_data {
-	struct poly_vert *imask;
-	struct poly_vert *omask;
-	struct scan_line *bounds;
-	int *bound_indexes;
-	int bounds_length;
+struct r_FillContext {
+	struct e_Status *all_edges, *possible_edges;
+	struct r_BufferStats rb;
 };
 
 /*
@@ -100,113 +77,121 @@ struct layer_init_data {
  * just the poly. Since the DEM code could end up being coupled with this, we'll keep it separate
  * for now.
  */
-static void preprocess_all_edges(struct r_fill_context *ctx, struct poly_vert *verts, int num_verts, struct e_status *open_edge) {
-    int i;
-    int xbeg;
-    int ybeg;
-    int xend;
-    int yend;
-    int dx;
-    int dy;
-    int temp_pos;
-    int xdist;
-    struct e_status *e_new;
-    struct e_status *next_edge;
-    struct e_status **next_edge_ref;
-    struct poly_vert *v;
-    /* set up pointers */
-    v = verts;
-    ctx->all_edges = NULL;
-    /* initialize some boundaries */
-    ctx->rb.xmax = v[0].x;
-    ctx->rb.xmin = v[0].x;
-    ctx->rb.ymax = v[0].y;
-    ctx->rb.ymin = v[0].y;
-    /* loop all verts */
-    for(i = 0; i < num_verts; i++) {
-        /* determine beginnings and endings of edges, linking last vertex to first vertex */
-        xbeg = v[i].x;
-        ybeg = v[i].y;
-        /* keep track of our x and y bounds */
-        if(xbeg >= ctx->rb.xmax) {
-            ctx->rb.xmax = xbeg;
-        } else if(xbeg <= ctx->rb.xmin) {
-            ctx->rb.xmin = xbeg;
-        }
-        if(ybeg >= ctx->rb.ymax) {
-            ctx->rb.ymax= ybeg;
-        } else if(ybeg <= ctx->rb.ymin) {
-            ctx->rb.ymin=ybeg;
-        }
-        if(i) {
-            /* we're not at the last vert, so end of the edge is the previous vertex */
-            xend = v[i - 1].x;
-            yend = v[i - 1].y;
-        } else {
-            /* we're at the first vertex, so the "end" of this edge is the last vertex */
-            xend = v[num_verts - 1].x;
-            yend = v[num_verts - 1].y;
-        }
-        /* make sure our edges are facing the correct direction */
-        if(ybeg > yend) {
-            /* flip the Xs */
-            temp_pos = xbeg;
-            xbeg = xend;
-            xend = temp_pos;
-            /* flip the Ys */
-            temp_pos = ybeg;
-            ybeg = yend;
-            yend = temp_pos;
-        }
-
-        /* calculate y delta */
-        dy = yend - ybeg;
-        /* dont draw horizontal lines directly, they are scanned as part of the edges they connect, so skip em. :) */
-        if(dy) {
-            /* create the edge and determine it's slope (for incremental line drawing) */
-            e_new = open_edge++;
-
-            /* calculate x delta */
-            dx = xend - xbeg;
-            if(dx > 0) {
-                e_new->xdir = 1;
-                xdist = dx;
-            } else {
-                e_new->xdir = -1;
-                xdist = -dx;
-            }
-
-            e_new->x = xbeg;
-            e_new->ybeg = ybeg;
-            e_new->num = dy;
-            e_new->drift_dec = dy;
-
-            /* calculate deltas for incremental drawing */
-            if(dx >= 0) {
-                e_new->drift = 0;
-            } else {
-                e_new->drift = -dy + 1;
-            }
-            if(dy >= xdist) {
-                e_new->drift_inc = xdist;
-                e_new->xshift = 0;
-            } else {
-                e_new->drift_inc = xdist % dy;
-                e_new->xshift = (xdist / dy) * e_new->xdir;
-            }
-            next_edge_ref = &ctx->all_edges;
-            /* link in all the edges, in sorted order */
-            for(;;) {
-                next_edge = *next_edge_ref;
-                if(!next_edge || (next_edge->ybeg > ybeg) || ((next_edge->ybeg == ybeg) && (next_edge->x >= xbeg))) {
-                    e_new->e_next = next_edge;
-                    *next_edge_ref = e_new;
-                    break;
-                }
-                next_edge_ref = &next_edge->e_next;
-            }
-        }
-    }
+static void preprocess_all_edges(struct r_FillContext *ctx,
+                                 struct PolyVert *verts, int num_verts, struct e_Status *open_edge)
+{
+	int i;
+	int xbeg;
+	int ybeg;
+	int xend;
+	int yend;
+	int dx;
+	int dy;
+	int temp_pos;
+	int xdist;
+	struct e_Status *e_new;
+	struct e_Status *next_edge;
+	struct e_Status **next_edge_ref;
+	struct PolyVert *v;
+	/* set up pointers */
+	v = verts;
+	ctx->all_edges = NULL;
+	/* initialize some boundaries */
+	ctx->rb.xmax = v[0].x;
+	ctx->rb.xmin = v[0].x;
+	ctx->rb.ymax = v[0].y;
+	ctx->rb.ymin = v[0].y;
+	/* loop all verts */
+	for (i = 0; i < num_verts; i++) {
+		/* determine beginnings and endings of edges, linking last vertex to first vertex */
+		xbeg = v[i].x;
+		ybeg = v[i].y;
+		/* keep track of our x and y bounds */
+		if (xbeg >= ctx->rb.xmax) {
+			ctx->rb.xmax = xbeg;
+		}
+		else if (xbeg <= ctx->rb.xmin) {
+			ctx->rb.xmin = xbeg;
+		}
+		if (ybeg >= ctx->rb.ymax) {
+			ctx->rb.ymax= ybeg;
+		}
+		else if (ybeg <= ctx->rb.ymin) {
+			ctx->rb.ymin=ybeg;
+		}
+		if (i) {
+			/* we're not at the last vert, so end of the edge is the previous vertex */
+			xend = v[i - 1].x;
+			yend = v[i - 1].y;
+		}
+		else {
+			/* we're at the first vertex, so the "end" of this edge is the last vertex */
+			xend = v[num_verts - 1].x;
+			yend = v[num_verts - 1].y;
+		}
+		/* make sure our edges are facing the correct direction */
+		if (ybeg > yend) {
+			/* flip the Xs */
+			temp_pos = xbeg;
+			xbeg = xend;
+			xend = temp_pos;
+			/* flip the Ys */
+			temp_pos = ybeg;
+			ybeg = yend;
+			yend = temp_pos;
+		}
+
+		/* calculate y delta */
+		dy = yend - ybeg;
+		/* dont draw horizontal lines directly, they are scanned as part of the edges they connect, so skip em. :) */
+		if (dy) {
+			/* create the edge and determine it's slope (for incremental line drawing) */
+			e_new = open_edge++;
+
+			/* calculate x delta */
+			dx = xend - xbeg;
+			if (dx > 0) {
+				e_new->xdir = 1;
+				xdist = dx;
+			}
+			else {
+				e_new->xdir = -1;
+				xdist = -dx;
+			}
+
+			e_new->x = xbeg;
+			e_new->ybeg = ybeg;
+			e_new->num = dy;
+			e_new->drift_dec = dy;
+
+			/* calculate deltas for incremental drawing */
+			if (dx >= 0) {
+				e_new->drift = 0;
+			}
+			else {
+				e_new->drift = -dy + 1;
+			}
+			if (dy >= xdist) {
+				e_new->drift_inc = xdist;
+				e_new->xshift = 0;
+			}
+			else {
+				e_new->drift_inc = xdist % dy;
+				e_new->xshift = (xdist / dy) * e_new->xdir;
+			}
+			next_edge_ref = &ctx->all_edges;
+			/* link in all the edges, in sorted order */
+			for (;;) {
+				next_edge = *next_edge_ref;
+				if (!next_edge || (next_edge->ybeg > ybeg) || ((next_edge->ybeg == ybeg) && (next_edge->x >= xbeg))) {
+					e_new->e_next = next_edge;
+					*next_edge_ref = e_new;
+					break;
+				}
+				next_edge_ref = &next_edge->e_next;
+			}
+		}
+	}
 }
 
 /*
@@ -214,257 +199,260 @@ static void preprocess_all_edges(struct r_fill_context *ctx, struct poly_vert *v
  * for speed, but waiting on final design choices for curve-data before eliminating data the DEM code will need
  * if it ends up being coupled with this function.
  */
-static int rast_scan_fill(struct r_fill_context *ctx, struct poly_vert *verts, int num_verts, float intensity) {
-    int x_curr;                 /* current pixel position in X */
-    int y_curr;                 /* current scan line being drawn */
-    int yp;                     /* y-pixel's position in frame buffer */
-    int swixd = 0;              /* whether or not edges switched position in X */
-    float *cpxl;                /* pixel pointers... */
-    float *mpxl;
-    float *spxl;
-    struct e_status *e_curr;    /* edge pointers... */
-    struct e_status *e_temp;
-    struct e_status *edgbuf;
-    struct e_status **edgec;
-
-
-    /*
-     * If the number of verts specified to render as a polygon is less than 3,
-     * return immediately. Obviously we cant render a poly with sides < 3. The
-     * return for this we set to 1, simply so it can be distinguished from the
-     * next place we could return, /home/guest/blender-svn/soc-2011-tomato/intern/raskter/raskter.
-     * which is a failure to allocate memory.
-     */
-    if(num_verts < 3) {
-        return(1);
-    }
-
-    /*
-     * Try to allocate an edge buffer in memory. needs to be the size of the edge tracking data
-     * multiplied by the number of edges, which is always equal to the number of verts in
-     * a 2D polygon. Here we return 0 to indicate a memory allocation failure, as opposed to a 1 for
-     * the preceeding error, which was a rasterization request on a 2D poly with less than
-     * 3 sides.
-     */
-    if((edgbuf = (struct e_status *)(malloc(sizeof(struct e_status) * num_verts))) == NULL) {
-        return(0);
-    }
-
-    /*
-     * Do some preprocessing on all edges. This constructs a table structure in memory of all
-     * the edge properties and can "flip" some edges so sorting works correctly.
-     */
-    preprocess_all_edges(ctx, verts, num_verts, edgbuf);
-
-    /* can happen with a zero area mask */
-    if (ctx->all_edges == NULL) {
-        free(edgbuf);
-        return(1);
-    }
-    /*
-     * Set the pointer for tracking the edges currently in processing to NULL to make sure
-     * we don't get some crazy value after initialization.
-     */
-    ctx->possible_edges = NULL;
-
-    /*
-     * Loop through all scan lines to be drawn. Since we sorted by Y values during
-     * preprocess_all_edges(), we can already exact values for the lowest and
-     * highest Y values we could possibly need by induction. The preprocessing sorted
-     * out edges by Y position, we can cycle the current edge being processed once
-     * it runs out of Y pixels. When we have no more edges, meaning the current edge
-     * is NULL after setting the "current" edge to be the previous current edge's
-     * "next" edge in the Y sorted edge connection chain, we can stop looping Y values,
-     * since we can't possibly have more scan lines if we ran out of edges. :)
-     *
-     * TODO: This clips Y to the frame buffer, which should be done in the preprocessor, but for now is done here.
-     *       Will get changed once DEM code gets in.
-     */
-    for(y_curr = ctx->all_edges->ybeg; (ctx->all_edges || ctx->possible_edges); y_curr++) {
-
-        /*
-         * Link any edges that start on the current scan line into the list of
-         * edges currently needed to draw at least this, if not several, scan lines.
-         */
-
-        /*
-         * Set the current edge to the beginning of the list of edges to be rasterized
-         * into this scan line.
-         *
-         * We could have lots of edge here, so iterate over all the edges needed. The
-         * preprocess_all_edges() function sorted edges by X within each chunk of Y sorting
-         * so we safely cycle edges to thier own "next" edges in order.
-         *
-         * At each iteration, make sure we still have a non-NULL edge.
-         */
-        for(edgec = &ctx->possible_edges; ctx->all_edges && (ctx->all_edges->ybeg == y_curr);) {
-            x_curr = ctx->all_edges->x;                  /* Set current X position. */
-            for(;;) {                                    /* Start looping edges. Will break when edges run out. */
-                e_curr = *edgec;                         /* Set up a current edge pointer. */
-                if(!e_curr || (e_curr->x >= x_curr)) {   /* If we have an no edge, or we need to skip some X-span, */
-                    e_temp = ctx->all_edges->e_next;     /* set a temp "next" edge to test. */
-                    *edgec = ctx->all_edges;             /* Add this edge to the list to be scanned. */
-                    ctx->all_edges->e_next = e_curr;     /* Set up the next edge. */
-                    edgec = &ctx->all_edges->e_next;     /* Set our list to the next edge's location in memory. */
-                    ctx->all_edges = e_temp;             /* Skip the NULL or bad X edge, set pointer to next edge. */
-                    break;                               /* Stop looping edges (since we ran out or hit empty X span. */
-                } else {
-                    edgec = &e_curr->e_next;             /* Set the pointer to the edge list the "next" edge. */
-                }
-            }
-        }
-
-        /*
-         * Determine the current scan line's offset in the pixel buffer based on its Y position.
-         * Basically we just multiply the current scan line's Y value by the number of pixels in each line.
-         */
-        yp = y_curr * ctx->rb.sizex;
-        /*
-         * Set a "scan line pointer" in memory. The location of the buffer plus the row offset.
-         */
-        spxl = ctx->rb.buf + (yp);
-        /*
-         * Set up the current edge to the first (in X) edge. The edges which could possibly be in this
-         * list were determined in the preceeding edge loop above. They were already sorted in X by the
-         * initial processing function.
-         *
-         * At each iteration, test for a NULL edge. Since we'll keep cycling edge's to their own "next" edge
-         * we will eventually hit a NULL when the list runs out.
-         */
-        for(e_curr = ctx->possible_edges; e_curr; e_curr = e_curr->e_next) {
-            /*
-             * Calculate a span of pixels to fill on the current scan line.
-             *
-             * Set the current pixel pointer by adding the X offset to the scan line's start offset.
-             * Cycle the current edge the next edge.
-             * Set the max X value to draw to be one less than the next edge's first pixel. This way we are
-             * sure not to ever get into a situation where we have overdraw. (drawing the same pixel more than
-             * one time because it's on a vertex connecting two edges)
-             *
-             * Then blast through all the pixels in the span, advancing the pointer and setting the color to white.
-             *
-             * TODO: Here we clip to the scan line, this is not efficient, and should be done in the preprocessor,
-             *       but for now it is done here until the DEM code comes in.
-             */
+static int rast_scan_fill(struct r_FillContext *ctx, struct PolyVert *verts, int num_verts, float intensity)
+{
+	int x_curr;                 /* current pixel position in X */
+	int y_curr;                 /* current scan line being drawn */
+	int yp;                     /* y-pixel's position in frame buffer */
+	int swixd = 0;              /* whether or not edges switched position in X */
+	float *cpxl;                /* pixel pointers... */
+	float *mpxl;
+	float *spxl;
+	struct e_Status *e_curr;    /* edge pointers... */
+	struct e_Status *e_temp;
+	struct e_Status *edgbuf;
+	struct e_Status **edgec;
+
+
+	/*
+	 * If the number of verts specified to render as a polygon is less than 3,
+	 * return immediately. Obviously we cant render a poly with sides < 3. The
+	 * return for this we set to 1, simply so it can be distinguished from the
+	 * next place we could return, /home/guest/blender-svn/soc-2011-tomato/intern/raskter/raskter.
+	 * which is a failure to allocate memory.
+	 */
+	if (num_verts < 3) {
+		return(1);
+	}
 
-            /* set up xmin and xmax bounds on this scan line */
-            cpxl = spxl + MAX2(e_curr->x, 0);
-            e_curr = e_curr->e_next;
-            mpxl = spxl + MIN2(e_curr->x, ctx->rb.sizex) - 1;
+	/*
+	 * Try to allocate an edge buffer in memory. needs to be the size of the edge tracking data
+	 * multiplied by the number of edges, which is always equal to the number of verts in
+	 * a 2D polygon. Here we return 0 to indicate a memory allocation failure, as opposed to a 1 for
+	 * the preceeding error, which was a rasterization request on a 2D poly with less than
+	 * 3 sides.
+	 */
+	if ((edgbuf = (struct e_Status *)(malloc(sizeof(struct e_Status) * num_verts))) == NULL) {
+		return(0);
+	}
 
-            if((y_curr >= 0) && (y_curr < ctx->rb.sizey)) {
-                /* draw the pixels. */
-                for(; cpxl <= mpxl; *cpxl++ += intensity);
-            }
-        }
+	/*
+	 * Do some preprocessing on all edges. This constructs a table structure in memory of all
+	 * the edge properties and can "flip" some edges so sorting works correctly.
+	 */
+	preprocess_all_edges(ctx, verts, num_verts, edgbuf);
 
-        /*
-         * Loop through all edges of polygon that could be hit by this scan line,
-         * and figure out their x-intersections with the next scan line.
-         *
-         * Either A.) we wont have any more edges to test, or B.) we just add on the
-         * slope delta computed in preprocessing step. Since this draws non-antialiased
-         * polygons, we dont have fractional positions, so we only move in x-direction
-         * when needed to get all the way to the next pixel over...
-         */
-        for(edgec = &ctx->possible_edges; (e_curr = *edgec);) {
-            if(!(--(e_curr->num))) {
-                *edgec = e_curr->e_next;
-            } else {
-                e_curr->x += e_curr->xshift;
-                if((e_curr->drift += e_curr->drift_inc) > 0) {
-                    e_curr->x += e_curr->xdir;
-                    e_curr->drift -= e_curr->drift_dec;
-                }
-                edgec = &e_curr->e_next;
-            }
-        }
-        /*
-         * It's possible that some edges may have crossed during the last step, so we'll be sure
-         * that we ALWAYS intersect scan lines in order by shuffling if needed to make all edges
-         * sorted by x-intersection coordinate. We'll always scan through at least once to see if
-         * edges crossed, and if so, we set the 'swixd' flag. If 'swixd' gets set on the initial
-         * pass, then we know we need to sort by x, so then cycle through edges again and perform
-         * the sort.-
-         */
-        if(ctx->possible_edges) {
-            for(edgec = &ctx->possible_edges; (e_curr = *edgec)->e_next; edgec = &(*edgec)->e_next) {
-                /* if the current edge hits scan line at greater X than the next edge, we need to exchange the edges */
-                if(e_curr->x > e_curr->e_next->x) {
-                    *edgec = e_curr->e_next;
-                    /* exchange the pointers */
-                    e_temp = e_curr->e_next->e_next;
-                    e_curr->e_next->e_next = e_curr;
-                    e_curr->e_next = e_temp;
-                    /* set flag that we had at least one switch */
-                    swixd = 1;
-                }
-            }
-            /* if we did have a switch, look for more (there will more if there was one) */
-            for(;;) {
-                /* reset exchange flag so it's only set if we encounter another one */
-                swixd = 0;
-                for(edgec = &ctx->possible_edges; (e_curr = *edgec)->e_next; edgec = &(*edgec)->e_next) {
-                    /* again, if current edge hits scan line at higher X than next edge, exchange the edges and set flag */
-                    if(e_curr->x > e_curr->e_next->x) {
-                        *edgec = e_curr->e_next;
-                        /* exchange the pointers */
-                        e_temp = e_curr->e_next->e_next;
-                        e_curr->e_next->e_next = e_curr;
-                        e_curr->e_next = e_temp;
-                        /* flip the exchanged flag */
-                        swixd = 1;
-                    }
-                }
-                /* if we had no exchanges, we're done reshuffling the pointers */
-                if(!swixd) {
-                    break;
-                }
-            }
-        }
-    }
+	/* can happen with a zero area mask */
+	if (ctx->all_edges == NULL) {
+		free(edgbuf);
+		return(1);
+	}
+	/*
+	 * Set the pointer for tracking the edges currently in processing to NULL to make sure
+	 * we don't get some crazy value after initialization.
+	 */
+	ctx->possible_edges = NULL;
+
+	/*
+	 * Loop through all scan lines to be drawn. Since we sorted by Y values during
+	 * preprocess_all_edges(), we can already exact values for the lowest and
+	 * highest Y values we could possibly need by induction. The preprocessing sorted
+	 * out edges by Y position, we can cycle the current edge being processed once
+	 * it runs out of Y pixels. When we have no more edges, meaning the current edge
+	 * is NULL after setting the "current" edge to be the previous current edge's
+	 * "next" edge in the Y sorted edge connection chain, we can stop looping Y values,
+	 * since we can't possibly have more scan lines if we ran out of edges. :)
+	 *
+	 * TODO: This clips Y to the frame buffer, which should be done in the preprocessor, but for now is done here.
+	 *       Will get changed once DEM code gets in.
+	 */
+	for (y_curr = ctx->all_edges->ybeg; (ctx->all_edges || ctx->possible_edges); y_curr++) {
+
+		/*
+		 * Link any edges that start on the current scan line into the list of
+		 * edges currently needed to draw at least this, if not several, scan lines.
+		 */
+
+		/*
+		 * Set the current edge to the beginning of the list of edges to be rasterized
+		 * into this scan line.
+		 *
+		 * We could have lots of edge here, so iterate over all the edges needed. The
+		 * preprocess_all_edges() function sorted edges by X within each chunk of Y sorting
+		 * so we safely cycle edges to thier own "next" edges in order.
+		 *
+		 * At each iteration, make sure we still have a non-NULL edge.
+		 */
+		for (edgec = &ctx->possible_edges; ctx->all_edges && (ctx->all_edges->ybeg == y_curr);) {
+			x_curr = ctx->all_edges->x;                  /* Set current X position. */
+			for (;;) {                                   /* Start looping edges. Will break when edges run out. */
+				e_curr = *edgec;                         /* Set up a current edge pointer. */
+				if (!e_curr || (e_curr->x >= x_curr)) {  /* If we have an no edge, or we need to skip some X-span, */
+					e_temp = ctx->all_edges->e_next;     /* set a temp "next" edge to test. */
+					*edgec = ctx->all_edges;             /* Add this edge to the list to be scanned. */
+					ctx->all_edges->e_next = e_curr;     /* Set up the next edge. */
+					edgec = &ctx->all_edges->e_next;     /* Set our list to the next edge's location in memory. */
+					ctx->all_edges = e_temp;             /* Skip the NULL or bad X edge, set pointer to next edge. */
+					break;                               /* Stop looping edges (since we ran out or hit empty X span. */
+				}
+				else {
+					edgec = &e_curr->e_next;             /* Set the pointer to the edge list the "next" edge. */
+				}
+			}
+		}
+
+		/*
+		 * Determine the current scan line's offset in the pixel buffer based on its Y position.
+		 * Basically we just multiply the current scan line's Y value by the number of pixels in each line.
+		 */
+		yp = y_curr * ctx->rb.sizex;
+		/*
+		 * Set a "scan line pointer" in memory. The location of the buffer plus the row offset.
+		 */
+		spxl = ctx->rb.buf + (yp);
+		/*
+		 * Set up the current edge to the first (in X) edge. The edges which could possibly be in this
+		 * list were determined in the preceeding edge loop above. They were already sorted in X by the
+		 * initial processing function.
+		 *
+		 * At each iteration, test for a NULL edge. Since we'll keep cycling edge's to their own "next" edge
+		 * we will eventually hit a NULL when the list runs out.
+		 */
+		for (e_curr = ctx->possible_edges; e_curr; e_curr = e_curr->e_next) {
+			/*
+			 * Calculate a span of pixels to fill on the current scan line.
+			 *
+			 * Set the current pixel pointer by adding the X offset to the scan line's start offset.
+			 * Cycle the current edge the next edge.
+			 * Set the max X value to draw to be one less than the next edge's first pixel. This way we are
+			 * sure not to ever get into a situation where we have overdraw. (drawing the same pixel more than
+			 * one time because it's on a vertex connecting two edges)
+			 *
+			 * Then blast through all the pixels in the span, advancing the pointer and setting the color to white.
+			 *
+			 * TODO: Here we clip to the scan line, this is not efficient, and should be done in the preprocessor,
+			 *       but for now it is done here until the DEM code comes in.
+			 */
+
+			/* set up xmin and xmax bounds on this scan line */
+			cpxl = spxl + MAX2(e_curr->x, 0);
+			e_curr = e_curr->e_next;
+			mpxl = spxl + MIN2(e_curr->x, ctx->rb.sizex) - 1;
+
+			if ((y_curr >= 0) && (y_curr < ctx->rb.sizey)) {
+				/* draw the pixels. */
+				for (; cpxl <= mpxl; *cpxl++ += intensity) {}
+			}
+		}
+
+		/*
+		 * Loop through all edges of polygon that could be hit by this scan line,
+		 * and figure out their x-intersections with the next scan line.
+		 *
+		 * Either A.) we wont have any more edges to test, or B.) we just add on the
+		 * slope delta computed in preprocessing step. Since this draws non-antialiased
+		 * polygons, we dont have fractional positions, so we only move in x-direction
+		 * when needed to get all the way to the next pixel over...
+		 */
+		for (edgec = &ctx->possible_edges; (e_curr = *edgec);) {
+			if (!(--(e_curr->num))) {
+				*edgec = e_curr->e_next;
+			}
+			else {
+				e_curr->x += e_curr->xshift;
+				if ((e_curr->drift += e_curr->drift_inc) > 0) {
+					e_curr->x += e_curr->xdir;
+					e_curr->drift -= e_curr->drift_dec;
+				}
+				edgec = &e_curr->e_next;
+			}
+		}
+		/*
+		 * It's possible that some edges may have crossed during the last step, so we'll be sure
+		 * that we ALWAYS intersect scan lines in order by shuffling if needed to make all edges
+		 * sorted by x-intersection coordinate. We'll always scan through at least once to see if
+		 * edges crossed, and if so, we set the 'swixd' flag. If 'swixd' gets set on the initial
+		 * pass, then we know we need to sort by x, so then cycle through edges again and perform
+		 * the sort.-
+		 */
+		if (ctx->possible_edges) {
+			for (edgec = &ctx->possible_edges; (e_curr = *edgec)->e_next; edgec = &(*edgec)->e_next) {
+				/* if the current edge hits scan line at greater X than the next edge, we need to exchange the edges */
+				if (e_curr->x > e_curr->e_next->x) {
+					*edgec = e_curr->e_next;
+					/* exchange the pointers */
+					e_temp = e_curr->e_next->e_next;
+					e_curr->e_next->e_next = e_curr;
+					e_curr->e_next = e_temp;
+					/* set flag that we had at least one switch */
+					swixd = 1;
+				}
+			}
+			/* if we did have a switch, look for more (there will more if there was one) */
+			for (;;) {
+				/* reset exchange flag so it's only set if we encounter another one */
+				swixd = 0;
+				for (edgec = &ctx->possible_edges; (e_curr = *edgec)->e_next; edgec = &(*edgec)->e_next) {
+					/* again, if current edge hits scan line at higher X than next edge, exchange the edges and set flag */
+					if (e_curr->x > e_curr->e_next->x) {
+						*edgec = e_curr->e_next;
+						/* exchange the pointers */
+						e_temp = e_curr->e_next->e_next;
+						e_curr->e_next->e_next = e_curr;
+						e_curr->e_next = e_temp;
+						/* flip the exchanged flag */
+						swixd = 1;
+					}
+				}
+				/* if we had no exchanges, we're done reshuffling the pointers */
+				if (!swixd) {
+					break;
+				}
+			}
+		}
+	}
 
-    free(edgbuf);
-    return 1;
+	free(edgbuf);
+	return 1;
 }
 
 int PLX_raskterize(float(*base_verts)[2], int num_base_verts,
                    float *buf, int buf_x, int buf_y) {
-    int i;                                   /* i: Loop counter. */
-    struct poly_vert *ply;                   /* ply: Pointer to a list of integer buffer-space vertex coordinates. */
-    struct r_fill_context ctx = {0};
-    const float buf_x_f = (float)(buf_x);
-    const float buf_y_f = (float)(buf_y);
-    /*
-     * Allocate enough memory for our poly_vert list. It'll be the size of the poly_vert
-     * data structure multiplied by the number of base_verts.
-     *
-     * In the event of a failure to allocate the memory, return 0, so this error can
-     * be distinguished as a memory allocation error.
-     */
-    if((ply = (struct poly_vert *)(malloc(sizeof(struct poly_vert) * num_base_verts))) == NULL) {
-        return(0);
-    }
-
-    ctx.rb.buf = buf;                            /* Set the output buffer pointer. */
-    ctx.rb.sizex = buf_x;                        /* Set the output buffer size in X. (width) */
-    ctx.rb.sizey = buf_y;                        /* Set the output buffer size in Y. (height) */
-    /*
-     * Loop over all verts passed in to be rasterized. Each vertex's X and Y coordinates are
-     * then converted from normalized screen space (0.0 <= POS <= 1.0) to integer coordinates
-     * in the buffer-space coordinates passed in inside buf_x and buf_y.
-     *
-     * It's worth noting that this function ONLY outputs fully white pixels in a mask. Every pixel
-     * drawn will be 1.0f in value, there is no anti-aliasing.
-     */
+	int i;                                   /* i: Loop counter. */
+	struct PolyVert *ply;                   /* ply: Pointer to a list of integer buffer-space vertex coordinates. */
+	struct r_FillContext ctx = {0};
+	const float buf_x_f = (float)(buf_x);
+	const float buf_y_f = (float)(buf_y);
+	/*
+	 * Allocate enough memory for our PolyVert list. It'll be the size of the PolyVert
+	 * data structure multiplied by the number of base_verts.
+	 *
+	 * In the event of a failure to allocate the memory, return 0, so this error can
+	 * be distinguished as a memory allocation error.
+	 */
+	if ((ply = (struct PolyVert *)(malloc(sizeof(struct PolyVert) * num_base_verts))) == NULL) {
+		return(0);
+	}
 
-	for(i = 0; i < num_base_verts; i++) {                           /* Loop over all base_verts. */
-		ply[i].x = (int)((base_verts[i][0] * buf_x_f) + 0.5f);       /* Range expand normalized X to integer buffer-space X. */
-		ply[i].y = (int)((base_verts[i][1] * buf_y_f) + 0.5f); /* Range expand normalized Y to integer buffer-space Y. */
+	ctx.rb.buf = buf;                            /* Set the output buffer pointer. */
+	ctx.rb.sizex = buf_x;                        /* Set the output buffer size in X. (width) */
+	ctx.rb.sizey = buf_y;                        /* Set the output buffer size in Y. (height) */
+	/*
+	 * Loop over all verts passed in to be rasterized. Each vertex's X and Y coordinates are
+	 * then converted from normalized screen space (0.0 <= POS <= 1.0) to integer coordinates
+	 * in the buffer-space coordinates passed in inside buf_x and buf_y.
+	 *
+	 * It's worth noting that this function ONLY outputs fully white pixels in a mask. Every pixel
+	 * drawn will be 1.0f in value, there is no anti-aliasing.
+	 */
+
+	for (i = 0; i < num_base_verts; i++) {                      /* Loop over all base_verts. */
+		ply[i].x = (int)((base_verts[i][0] * buf_x_f) + 0.5f);  /* Range expand normalized X to integer buffer-space X. */
+		ply[i].y = (int)((base_verts[i][1] * buf_y_f) + 0.5f);  /* Range expand normalized Y to integer buffer-space Y. */
 	}
 
 	i = rast_scan_fill(&ctx, ply, num_base_verts,1.0f);  /* Call our rasterizer, passing in the integer coords for each vert. */
 
-    free(ply);                                      /* Free the memory allocated for the integer coordinate table. */
-    return(i);                                      /* Return the value returned by the rasterizer. */
+	free(ply);                                      /* Free the memory allocated for the integer coordinate table. */
+	return(i);                                      /* Return the value returned by the rasterizer. */
 }