| 1 | /*
|
|---|
| 2 | * $Id: renderedge.h,v 1.3 2005/07/03 07:02:08 daniels Exp $
|
|---|
| 3 | *
|
|---|
| 4 | * Copyright © 2004 Keith Packard
|
|---|
| 5 | *
|
|---|
| 6 | * Permission to use, copy, modify, distribute, and sell this software and its
|
|---|
| 7 | * documentation for any purpose is hereby granted without fee, provided that
|
|---|
| 8 | * the above copyright notice appear in all copies and that both that
|
|---|
| 9 | * copyright notice and this permission notice appear in supporting
|
|---|
| 10 | * documentation, and that the name of Keith Packard not be used in
|
|---|
| 11 | * advertising or publicity pertaining to distribution of the software without
|
|---|
| 12 | * specific, written prior permission. Keith Packard makes no
|
|---|
| 13 | * representations about the suitability of this software for any purpose. It
|
|---|
| 14 | * is provided "as is" without express or implied warranty.
|
|---|
| 15 | *
|
|---|
| 16 | * KEITH PACKARD DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
|
|---|
| 17 | * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
|
|---|
| 18 | * EVENT SHALL KEITH PACKARD BE LIABLE FOR ANY SPECIAL, INDIRECT OR
|
|---|
| 19 | * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE,
|
|---|
| 20 | * DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
|
|---|
| 21 | * TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
|
|---|
| 22 | * PERFORMANCE OF THIS SOFTWARE.
|
|---|
| 23 | */
|
|---|
| 24 |
|
|---|
| 25 | #ifndef _RENDEREDGE_H_
|
|---|
| 26 | #define _RENDEREDGE_H_
|
|---|
| 27 |
|
|---|
| 28 | #include "picturestr.h"
|
|---|
| 29 |
|
|---|
| 30 | #define MAX_ALPHA(n) ((1 << (n)) - 1)
|
|---|
| 31 | #define N_Y_FRAC(n) ((n) == 1 ? 1 : (1 << ((n)/2)) - 1)
|
|---|
| 32 | #define N_X_FRAC(n) ((1 << ((n)/2)) + 1)
|
|---|
| 33 |
|
|---|
| 34 | #define STEP_Y_SMALL(n) (xFixed1 / N_Y_FRAC(n))
|
|---|
| 35 | #define STEP_Y_BIG(n) (xFixed1 - (N_Y_FRAC(n) - 1) * STEP_Y_SMALL(n))
|
|---|
| 36 |
|
|---|
| 37 | #define Y_FRAC_FIRST(n) (STEP_Y_SMALL(n) / 2)
|
|---|
| 38 | #define Y_FRAC_LAST(n) (Y_FRAC_FIRST(n) + (N_Y_FRAC(n) - 1) * STEP_Y_SMALL(n))
|
|---|
| 39 |
|
|---|
| 40 | #define STEP_X_SMALL(n) (xFixed1 / N_X_FRAC(n))
|
|---|
| 41 | #define STEP_X_BIG(n) (xFixed1 - (N_X_FRAC(n) - 1) * STEP_X_SMALL(n))
|
|---|
| 42 |
|
|---|
| 43 | #define X_FRAC_FIRST(n) (STEP_X_SMALL(n) / 2)
|
|---|
| 44 | #define X_FRAC_LAST(n) (X_FRAC_FIRST(n) + (N_X_FRAC(n) - 1) * STEP_X_SMALL(n))
|
|---|
| 45 |
|
|---|
| 46 | #define RenderSamplesX(x,n) ((n) == 1 ? 0 : (xFixedFrac (x) + X_FRAC_FIRST(n)) / STEP_X_SMALL(n))
|
|---|
| 47 |
|
|---|
| 48 | /*
|
|---|
| 49 | * An edge structure. This represents a single polygon edge
|
|---|
| 50 | * and can be quickly stepped across small or large gaps in the
|
|---|
| 51 | * sample grid
|
|---|
| 52 | */
|
|---|
| 53 |
|
|---|
| 54 | typedef struct {
|
|---|
| 55 | xFixed x;
|
|---|
| 56 | xFixed e;
|
|---|
| 57 | xFixed stepx;
|
|---|
| 58 | xFixed signdx;
|
|---|
| 59 | xFixed dy;
|
|---|
| 60 | xFixed dx;
|
|---|
| 61 |
|
|---|
| 62 | xFixed stepx_small;
|
|---|
| 63 | xFixed stepx_big;
|
|---|
| 64 | xFixed dx_small;
|
|---|
| 65 | xFixed dx_big;
|
|---|
| 66 | } RenderEdge;
|
|---|
| 67 |
|
|---|
| 68 | /*
|
|---|
| 69 | * Step across a small sample grid gap
|
|---|
| 70 | */
|
|---|
| 71 | #define RenderEdgeStepSmall(edge) { \
|
|---|
| 72 | edge->x += edge->stepx_small; \
|
|---|
| 73 | edge->e += edge->dx_small; \
|
|---|
| 74 | if (edge->e > 0) \
|
|---|
| 75 | { \
|
|---|
| 76 | edge->e -= edge->dy; \
|
|---|
| 77 | edge->x += edge->signdx; \
|
|---|
| 78 | } \
|
|---|
| 79 | }
|
|---|
| 80 |
|
|---|
| 81 | /*
|
|---|
| 82 | * Step across a large sample grid gap
|
|---|
| 83 | */
|
|---|
| 84 | #define RenderEdgeStepBig(edge) { \
|
|---|
| 85 | edge->x += edge->stepx_big; \
|
|---|
| 86 | edge->e += edge->dx_big; \
|
|---|
| 87 | if (edge->e > 0) \
|
|---|
| 88 | { \
|
|---|
| 89 | edge->e -= edge->dy; \
|
|---|
| 90 | edge->x += edge->signdx; \
|
|---|
| 91 | } \
|
|---|
| 92 | }
|
|---|
| 93 |
|
|---|
| 94 | xFixed
|
|---|
| 95 | RenderSampleCeilY (xFixed y, int bpp);
|
|---|
| 96 |
|
|---|
| 97 | xFixed
|
|---|
| 98 | RenderSampleFloorY (xFixed y, int bpp);
|
|---|
| 99 |
|
|---|
| 100 | void
|
|---|
| 101 | RenderEdgeStep (RenderEdge *e, int n);
|
|---|
| 102 |
|
|---|
| 103 | void
|
|---|
| 104 | RenderEdgeInit (RenderEdge *e,
|
|---|
| 105 | int bpp,
|
|---|
| 106 | xFixed y_start,
|
|---|
| 107 | xFixed x_top,
|
|---|
| 108 | xFixed y_top,
|
|---|
| 109 | xFixed x_bot,
|
|---|
| 110 | xFixed y_bot);
|
|---|
| 111 |
|
|---|
| 112 | void
|
|---|
| 113 | RenderLineFixedEdgeInit (RenderEdge *e,
|
|---|
| 114 | int bpp,
|
|---|
| 115 | xFixed y,
|
|---|
| 116 | xLineFixed *line,
|
|---|
| 117 | int x_off,
|
|---|
| 118 | int y_off);
|
|---|
| 119 |
|
|---|
| 120 | #endif /* _RENDEREDGE_H_ */
|
|---|
