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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 GLAPIENTRY
41 _mesa_ClearStencil( GLint s );
42 
43 
44 void GLAPIENTRY
45 _mesa_StencilFunc_no_error(GLenum func, GLint ref, GLuint mask);
46 
47 extern void GLAPIENTRY
48 _mesa_StencilFunc(GLenum func, GLint ref, GLuint mask);
49 
50 
51 extern void GLAPIENTRY
52 _mesa_StencilMask( GLuint mask );
53 
54 void GLAPIENTRY
55 _mesa_StencilOp_no_error(GLenum fail, GLenum zfail, GLenum zpass);
56 
57 extern void GLAPIENTRY
58 _mesa_StencilOp(GLenum fail, GLenum zfail, GLenum zpass);
59 
60 
61 extern void GLAPIENTRY
62 _mesa_ActiveStencilFaceEXT(GLenum face);
63 
64 void GLAPIENTRY
65 _mesa_StencilOpSeparate_no_error(GLenum face, GLenum fail, GLenum zfail,
66                                  GLenum zpass);
67 
68 extern void GLAPIENTRY
69 _mesa_StencilOpSeparate(GLenum face, GLenum fail, GLenum zfail, GLenum zpass);
70 
71 
72 void GLAPIENTRY
73 _mesa_StencilFuncSeparate_no_error(GLenum face, GLenum func, GLint ref,
74                                    GLuint mask);
75 
76 extern void GLAPIENTRY
77 _mesa_StencilFuncSeparate(GLenum face, GLenum func, GLint ref, GLuint mask);
78 
79 
80 extern void GLAPIENTRY
81 _mesa_StencilFuncSeparateATI(GLenum frontfunc, GLenum backfunc, GLint ref, GLuint mask);
82 
83 void GLAPIENTRY
84 _mesa_StencilMaskSeparate_no_error(GLenum face, GLuint mask);
85 
86 extern void GLAPIENTRY
87 _mesa_StencilMaskSeparate(GLenum face, GLuint mask);
88 
89 extern void
90 _mesa_init_stencil( struct gl_context * ctx );
91 
92 /* From the GL 4.3 spec, 17.3.5:
93  *    "Stencil comparison operations and queries of <ref> clamp its value
94  *    to the range [0, 2^s-1], where <s> is the number of bits in the
95  *    stencil buffer attached to the draw framebuffer."
96  */
97 
98 static inline GLint
_mesa_get_stencil_ref(struct gl_context const * ctx,int face)99 _mesa_get_stencil_ref(struct gl_context const *ctx, int face)
100 {
101    GLint stencilMax = (1 << ctx->DrawBuffer->Visual.stencilBits) - 1;
102    GLint ref = ctx->Stencil.Ref[face];
103    return CLAMP(ref, 0, stencilMax);
104 }
105 
106 static inline bool
_mesa_stencil_is_enabled(const struct gl_context * ctx)107 _mesa_stencil_is_enabled(const struct gl_context *ctx)
108 {
109    return ctx->Stencil.Enabled &&
110           ctx->DrawBuffer->Visual.stencilBits > 0;
111 }
112 
113 static inline bool
_mesa_stencil_is_two_sided(const struct gl_context * ctx)114 _mesa_stencil_is_two_sided(const struct gl_context *ctx)
115 {
116    const int face = ctx->Stencil._BackFace;
117 
118    return _mesa_stencil_is_enabled(ctx) &&
119           (ctx->Stencil.Function[0] != ctx->Stencil.Function[face] ||
120            ctx->Stencil.FailFunc[0] != ctx->Stencil.FailFunc[face] ||
121            ctx->Stencil.ZPassFunc[0] != ctx->Stencil.ZPassFunc[face] ||
122            ctx->Stencil.ZFailFunc[0] != ctx->Stencil.ZFailFunc[face] ||
123            ctx->Stencil.Ref[0] != ctx->Stencil.Ref[face] ||
124            ctx->Stencil.ValueMask[0] != ctx->Stencil.ValueMask[face] ||
125            ctx->Stencil.WriteMask[0] != ctx->Stencil.WriteMask[face]);
126 }
127 
128 static inline bool
_mesa_stencil_is_write_enabled(const struct gl_context * ctx,bool is_two_sided)129 _mesa_stencil_is_write_enabled(const struct gl_context *ctx, bool is_two_sided)
130 {
131    return _mesa_stencil_is_enabled(ctx) &&
132           (ctx->Stencil.WriteMask[0] != 0 ||
133            (is_two_sided &&
134             ctx->Stencil.WriteMask[ctx->Stencil._BackFace] != 0));
135 }
136 
137 #endif
138