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
38 struct gl_context;
39
40 extern 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
49 static inline GLint
_mesa_get_stencil_ref(struct gl_context const * ctx,int face)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
57 static inline bool
_mesa_stencil_is_enabled(const struct gl_context * ctx)58 _mesa_stencil_is_enabled(const struct gl_context *ctx)
59 {
60 return ctx->Stencil.Enabled &&
61 ctx->DrawBuffer->Visual.stencilBits > 0;
62 }
63
64 static inline bool
_mesa_stencil_is_two_sided(const struct gl_context * ctx)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
79 static inline bool
_mesa_stencil_is_write_enabled(const struct gl_context * ctx,bool is_two_sided)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