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Diffstat (limited to 'render/renderedge.h')
| -rw-r--r-- | render/renderedge.h | 120 |
1 files changed, 120 insertions, 0 deletions
diff --git a/render/renderedge.h b/render/renderedge.h new file mode 100644 index 000000000..d621d9dcf --- /dev/null +++ b/render/renderedge.h @@ -0,0 +1,120 @@ +/* + * $Id$ + * + * Copyright © 2004 Keith Packard + * + * Permission to use, copy, modify, distribute, and sell this software and its + * documentation for any purpose is hereby granted without fee, provided that + * the above copyright notice appear in all copies and that both that + * copyright notice and this permission notice appear in supporting + * documentation, and that the name of Keith Packard not be used in + * advertising or publicity pertaining to distribution of the software without + * specific, written prior permission. Keith Packard makes no + * representations about the suitability of this software for any purpose. It + * is provided "as is" without express or implied warranty. + * + * KEITH PACKARD DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, + * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO + * EVENT SHALL KEITH PACKARD BE LIABLE FOR ANY SPECIAL, INDIRECT OR + * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, + * DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER + * TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR + * PERFORMANCE OF THIS SOFTWARE. + */ + +#ifndef _RENDEREDGE_H_ +#define _RENDEREDGE_H_ + +#include "picturestr.h" + +#define MAX_ALPHA(n) ((1 << (n)) - 1) +#define N_Y_FRAC(n) ((n) == 1 ? 1 : (1 << ((n)/2)) - 1) +#define N_X_FRAC(n) ((1 << ((n)/2)) + 1) + +#define STEP_Y_SMALL(n) (xFixed1 / N_Y_FRAC(n)) +#define STEP_Y_BIG(n) (xFixed1 - (N_Y_FRAC(n) - 1) * STEP_Y_SMALL(n)) + +#define Y_FRAC_FIRST(n) (STEP_Y_SMALL(n) / 2) +#define Y_FRAC_LAST(n) (Y_FRAC_FIRST(n) + (N_Y_FRAC(n) - 1) * STEP_Y_SMALL(n)) + +#define STEP_X_SMALL(n) (xFixed1 / N_X_FRAC(n)) +#define STEP_X_BIG(n) (xFixed1 - (N_X_FRAC(n) - 1) * STEP_X_SMALL(n)) + +#define X_FRAC_FIRST(n) (STEP_X_SMALL(n) / 2) +#define X_FRAC_LAST(n) (X_FRAC_FIRST(n) + (N_X_FRAC(n) - 1) * STEP_X_SMALL(n)) + +#define RenderSamplesX(x,n) ((n) == 1 ? 0 : (xFixedFrac (x) + X_FRAC_FIRST(n)) / STEP_X_SMALL(n)) + +/* + * An edge structure. This represents a single polygon edge + * and can be quickly stepped across small or large gaps in the + * sample grid + */ + +typedef struct { + xFixed x; + xFixed e; + xFixed stepx; + xFixed signdx; + xFixed dy; + xFixed dx; + + xFixed stepx_small; + xFixed stepx_big; + xFixed dx_small; + xFixed dx_big; +} RenderEdge; + +/* + * Step across a small sample grid gap + */ +#define RenderEdgeStepSmall(edge) { \ + edge->x += edge->stepx_small; \ + edge->e += edge->dx_small; \ + if (edge->e > 0) \ + { \ + edge->e -= edge->dy; \ + edge->x += edge->signdx; \ + } \ +} + +/* + * Step across a large sample grid gap + */ +#define RenderEdgeStepBig(edge) { \ + edge->x += edge->stepx_big; \ + edge->e += edge->dx_big; \ + if (edge->e > 0) \ + { \ + edge->e -= edge->dy; \ + edge->x += edge->signdx; \ + } \ +} + +xFixed +RenderSampleCeilY (xFixed y, int bpp); + +xFixed +RenderSampleFloorY (xFixed y, int bpp); + +void +RenderEdgeStep (RenderEdge *e, int n); + +void +RenderEdgeInit (RenderEdge *e, + int bpp, + xFixed y_start, + xFixed x_top, + xFixed y_top, + xFixed x_bot, + xFixed y_bot); + +void +RenderLineFixedEdgeInit (RenderEdge *e, + int bpp, + xFixed y, + xLineFixed *line, + int x_off, + int y_off); + +#endif /* _RENDEREDGE_H_ */ |