diff options
Diffstat (limited to 'twin_poly.c')
| -rw-r--r-- | twin_poly.c | 47 |
1 files changed, 31 insertions, 16 deletions
diff --git a/twin_poly.c b/twin_poly.c index d797c1e..e8aa7f2 100644 --- a/twin_poly.c +++ b/twin_poly.c @@ -24,6 +24,17 @@ #include "twinint.h" +typedef struct _twin_edge { + struct _twin_edge *next; + twin_sfixed_t top, bot; + twin_sfixed_t x; + twin_sfixed_t e; + twin_sfixed_t dx, dy; + twin_sfixed_t inc_x; + twin_sfixed_t step_x; + int winding; +} twin_edge_t; + #define TWIN_POLY_SHIFT 2 #define TWIN_POLY_FIXED_SHIFT (4 - TWIN_POLY_SHIFT) #define TWIN_POLY_SAMPLE (1 << TWIN_POLY_SHIFT) @@ -72,13 +83,14 @@ _twin_sfixed_grid_ceil (twin_sfixed_t f) #define DBGOUT(x...) #endif -int -_twin_edge_build (twin_spoint_t *vertices, int nvertices, twin_edge_t *edges) +static int +_twin_edge_build (twin_spoint_t *vertices, int nvertices, twin_edge_t *edges, + twin_sfixed_t dx, twin_sfixed_t dy) { int v, nv; int tv, bv; int e; - twin_sfixed_t y; + twin_sfixed_t y; e = 0; for (v = 0; v < nvertices; v++) @@ -107,12 +119,12 @@ _twin_edge_build (twin_spoint_t *vertices, int nvertices, twin_edge_t *edges) } /* snap top to first grid point in pixmap */ - y = _twin_sfixed_grid_ceil (vertices[tv].y); + y = _twin_sfixed_grid_ceil (vertices[tv].y + dy); if (y < TWIN_POLY_START) y = TWIN_POLY_START; /* skip vertices which don't span a sample row */ - if (y >= vertices[bv].y) + if (y >= vertices[bv].y + dy) continue; /* Compute bresenham terms */ @@ -128,10 +140,10 @@ _twin_edge_build (twin_spoint_t *vertices, int nvertices, twin_edge_t *edges) edges[e].step_x = edges[e].inc_x * (edges[e].dx / edges[e].dy); edges[e].dx = edges[e].dx % edges[e].dy; - edges[e].top = vertices[tv].y; - edges[e].bot = vertices[bv].y; + edges[e].top = vertices[tv].y + dy; + edges[e].bot = vertices[bv].y + dy; - edges[e].x = vertices[tv].x; + edges[e].x = vertices[tv].x + dx; edges[e].e = 0; /* step to first grid point */ @@ -254,7 +266,7 @@ _span_fill (twin_pixmap_t *pixmap, } } -void +static void _twin_edge_fill (twin_pixmap_t *pixmap, twin_edge_t *edges, int nedges) { twin_edge_t *active, *a, *n, **prev; @@ -336,13 +348,15 @@ _twin_edge_fill (twin_pixmap_t *pixmap, twin_edge_t *edges, int nedges) } void -twin_fill_path (twin_pixmap_t *pixmap, twin_path_t *path) +twin_fill_path (twin_pixmap_t *pixmap, twin_path_t *path, int dx, int dy) { - twin_edge_t *edges; - int nedges, n; - int nalloc; - int s; - int p; + twin_edge_t *edges; + int nedges, n; + int nalloc; + int s; + int p; + twin_sfixed_t sdx = twin_int_to_sfixed (dx); + twin_sfixed_t sdy = twin_int_to_sfixed (dy); nalloc = path->npoints + path->nsublen + 1; edges = malloc (sizeof (twin_edge_t) * nalloc); @@ -360,7 +374,8 @@ twin_fill_path (twin_pixmap_t *pixmap, twin_path_t *path) npoints = sublen - p; if (npoints > 1) { - n = _twin_edge_build (path->points + p, npoints, edges + nedges); + n = _twin_edge_build (path->points + p, npoints, edges + nedges, + sdx, sdy); p = sublen; nedges += n; } |