xref: /third_party/mesa3d/src/mesa/main/stencil.h (revision bf215546) 
1/**
2 * \file stencil.h
3 * Stencil operations.
4 */
5
6/*
7 * Mesa 3-D graphics library
8 *
9 * Copyright (C) 1999-2007  Brian Paul   All Rights Reserved.
10 *
11 * Permission is hereby granted, free of charge, to any person obtaining a
12 * copy of this software and associated documentation files (the "Software"),
13 * to deal in the Software without restriction, including without limitation
14 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
15 * and/or sell copies of the Software, and to permit persons to whom the
16 * Software is furnished to do so, subject to the following conditions:
17 *
18 * The above copyright notice and this permission notice shall be included
19 * in all copies or substantial portions of the Software.
20 *
21 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
22 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
23 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
24 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
25 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
26 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
27 * OTHER DEALINGS IN THE SOFTWARE.
28 */
29
30
31#ifndef STENCIL_H
32#define STENCIL_H
33
34
35#include "glheader.h"
36#include "macros.h"
37
38struct gl_context;
39
40extern void
41_mesa_init_stencil( struct gl_context * ctx );
42
43/* From the GL 4.3 spec, 17.3.5:
44 *    "Stencil comparison operations and queries of <ref> clamp its value
45 *    to the range [0, 2^s-1], where <s> is the number of bits in the
46 *    stencil buffer attached to the draw framebuffer."
47 */
48
49static inline GLint
50_mesa_get_stencil_ref(struct gl_context const *ctx, int face)
51{
52   GLint stencilMax = (1 << ctx->DrawBuffer->Visual.stencilBits) - 1;
53   GLint ref = ctx->Stencil.Ref[face];
54   return CLAMP(ref, 0, stencilMax);
55}
56
57static inline bool
58_mesa_stencil_is_enabled(const struct gl_context *ctx)
59{
60   return ctx->Stencil.Enabled &&
61          ctx->DrawBuffer->Visual.stencilBits > 0;
62}
63
64static inline bool
65_mesa_stencil_is_two_sided(const struct gl_context *ctx)
66{
67   const int face = ctx->Stencil._BackFace;
68
69   return _mesa_stencil_is_enabled(ctx) &&
70          (ctx->Stencil.Function[0] != ctx->Stencil.Function[face] ||
71           ctx->Stencil.FailFunc[0] != ctx->Stencil.FailFunc[face] ||
72           ctx->Stencil.ZPassFunc[0] != ctx->Stencil.ZPassFunc[face] ||
73           ctx->Stencil.ZFailFunc[0] != ctx->Stencil.ZFailFunc[face] ||
74           ctx->Stencil.Ref[0] != ctx->Stencil.Ref[face] ||
75           ctx->Stencil.ValueMask[0] != ctx->Stencil.ValueMask[face] ||
76           ctx->Stencil.WriteMask[0] != ctx->Stencil.WriteMask[face]);
77}
78
79static inline bool
80_mesa_stencil_is_write_enabled(const struct gl_context *ctx, bool is_two_sided)
81{
82   return _mesa_stencil_is_enabled(ctx) &&
83          (ctx->Stencil.WriteMask[0] != 0 ||
84           (is_two_sided &&
85            ctx->Stencil.WriteMask[ctx->Stencil._BackFace] != 0));
86}
87
88#endif
89