ReactOS 0.4.15-dev-5666-gc548b97
alpha.c
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1/* $Id: alpha.c,v 1.5 1997/07/24 01:24:28 brianp Exp $ */
2
3/*
4 * Mesa 3-D graphics library
5 * Version: 2.4
6 * Copyright (C) 1995-1997 Brian Paul
7 *
8 * This library is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU Library General Public
10 * License as published by the Free Software Foundation; either
11 * version 2 of the License, or (at your option) any later version.
12 *
13 * This library is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 * Library General Public License for more details.
17 *
18 * You should have received a copy of the GNU Library General Public
19 * License along with this library; if not, write to the Free
20 * Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
21 */
22
23
24/*
25 * $Log: alpha.c,v $
26 * Revision 1.5 1997/07/24 01:24:28 brianp
27 * changed precompiled header symbol from PCH to PC_HEADER
28 *
29 * Revision 1.4 1997/05/28 03:23:09 brianp
30 * added precompiled header (PCH) support
31 *
32 * Revision 1.3 1997/03/13 03:07:53 brianp
33 * optimized gl_alpha_test() by removing conditional from inside loops
34 *
35 * Revision 1.2 1996/09/15 14:15:54 brianp
36 * now use GLframebuffer and GLvisual
37 *
38 * Revision 1.1 1996/09/13 01:38:16 brianp
39 * Initial revision
40 *
41 */
42
43
44#ifdef PC_HEADER
45#include "all.h"
46#else
47#include "alpha.h"
48#include "context.h"
49#include "types.h"
50#include "dlist.h"
51#include "macros.h"
52#endif
53
54
55
57{
58 if (INSIDE_BEGIN_END(ctx)) {
59 gl_error( ctx, GL_INVALID_OPERATION, "glAlphaFunc" );
60 return;
61 }
62 switch (func) {
63 case GL_NEVER:
64 case GL_LESS:
65 case GL_EQUAL:
66 case GL_LEQUAL:
67 case GL_GREATER:
68 case GL_NOTEQUAL:
69 case GL_GEQUAL:
70 case GL_ALWAYS:
71 ctx->Color.AlphaFunc = func;
72 ctx->Color.AlphaRef = CLAMP( ref, 0.0F, 1.0F );
73 ctx->Color.AlphaRefUbyte = (GLubyte) (ctx->Color.AlphaRef
74 * ctx->Visual->AlphaScale);
75 break;
76 default:
77 gl_error( ctx, GL_INVALID_ENUM, "glAlphaFunc(func)" );
78 break;
79 }
80}
81
82
83
84
85/*
86 * Apply the alpha test to a span of pixels.
87 * In/Out: mask - current pixel mask. Pixels which fail the alpha test
88 * will set the corresponding mask flag to 0.
89 * Return: 0 = all pixels in the span failed the alpha test.
90 * 1 = one or more pixels passed the alpha test.
91 */
93 GLuint n, const GLubyte alpha[], GLubyte mask[] )
94{
95 GLuint i;
96 GLubyte ref = ctx->Color.AlphaRefUbyte;
97
98 /* switch cases ordered from most frequent to less frequent */
99 switch (ctx->Color.AlphaFunc) {
100 case GL_LESS:
101 for (i=0;i<n;i++) {
102 mask[i] &= (alpha[i] < ref);
103 }
104 return 1;
105 case GL_LEQUAL:
106 for (i=0;i<n;i++) {
107 mask[i] &= (alpha[i] <= ref);
108 }
109 return 1;
110 case GL_GEQUAL:
111 for (i=0;i<n;i++) {
112 mask[i] &= (alpha[i] >= ref);
113 }
114 return 1;
115 case GL_GREATER:
116 for (i=0;i<n;i++) {
117 mask[i] &= (alpha[i] > ref);
118 }
119 return 1;
120 case GL_NOTEQUAL:
121 for (i=0;i<n;i++) {
122 mask[i] &= (alpha[i] != ref);
123 }
124 return 1;
125 case GL_EQUAL:
126 for (i=0;i<n;i++) {
127 mask[i] &= (alpha[i] == ref);
128 }
129 return 1;
130 case GL_ALWAYS:
131 /* do nothing */
132 return 1;
133 case GL_NEVER:
134 /* caller should check for zero! */
135 return 0;
136 default:
137 gl_problem( ctx, "Invalid alpha test in gl_alpha_test" );
138 return 0;
139 }
140 /* Never get here */
141 return 1;
142}
GLint gl_alpha_test(GLcontext *ctx, GLuint n, const GLubyte alpha[], GLubyte mask[])
Definition: alpha.c:92
void gl_AlphaFunc(GLcontext *ctx, GLenum func, GLclampf ref)
Definition: alpha.c:56
void gl_problem(const GLcontext *ctx, const char *s)
Definition: context.c:1394
void gl_error(GLcontext *ctx, GLenum error, const char *s)
Definition: context.c:1421
#define GL_NEVER
Definition: gl.h:293
unsigned char GLubyte
Definition: gl.h:157
#define GL_ALWAYS
Definition: gl.h:300
#define GL_LESS
Definition: gl.h:294
#define GL_NOTEQUAL
Definition: gl.h:298
#define GL_INVALID_OPERATION
Definition: gl.h:696
GLclampf GLclampf GLclampf alpha
Definition: gl.h:1740
unsigned int GLenum
Definition: gl.h:150
unsigned int GLuint
Definition: gl.h:159
#define GL_LEQUAL
Definition: gl.h:296
#define GL_GEQUAL
Definition: gl.h:299
#define GL_GREATER
Definition: gl.h:297
#define GL_EQUAL
Definition: gl.h:295
int GLint
Definition: gl.h:156
float GLclampf
Definition: gl.h:162
#define GL_INVALID_ENUM
Definition: gl.h:694
GLenum func
Definition: glext.h:6028
GLdouble n
Definition: glext.h:7729
GLenum GLint GLuint mask
Definition: glext.h:6028
GLsizei GLenum const GLvoid GLsizei GLenum GLbyte GLbyte GLbyte GLdouble GLdouble GLdouble GLfloat GLfloat GLfloat GLint GLint GLint GLshort GLshort GLshort GLubyte GLubyte GLubyte GLuint GLuint GLuint GLushort GLushort GLushort GLbyte GLbyte GLbyte GLbyte GLdouble GLdouble GLdouble GLdouble GLfloat GLfloat GLfloat GLfloat GLint GLint GLint GLint GLshort GLshort GLshort GLshort GLubyte GLubyte GLubyte GLubyte GLuint GLuint GLuint GLuint GLushort GLushort GLushort GLushort GLboolean const GLdouble const GLfloat const GLint const GLshort const GLbyte const GLdouble const GLfloat const GLint const GLshort const GLdouble const GLfloat const GLint const GLshort const GLdouble const GLfloat const GLint const GLshort const GLdouble const GLfloat const GLint const GLshort const GLdouble const GLdouble const GLfloat const GLfloat const GLint const GLint const GLshort const GLshort const GLdouble const GLfloat const GLint const GLshort const GLdouble const GLfloat const GLint const GLshort const GLdouble const GLfloat const GLint const GLshort const GLdouble const GLfloat const GLint const GLshort const GLdouble const GLfloat const GLint const GLshort const GLdouble const GLfloat const GLint const GLshort const GLdouble const GLfloat const GLint const GLshort GLenum GLenum GLenum GLfloat GLenum GLint GLenum GLenum GLenum GLfloat GLenum GLenum GLint GLenum GLfloat GLenum GLint GLint GLushort GLenum GLenum GLfloat GLenum GLenum GLint GLfloat const GLubyte GLenum GLenum GLenum const GLfloat GLenum GLenum const GLint GLenum GLint GLint GLsizei GLsizei GLint GLenum GLenum const GLvoid GLenum GLenum const GLfloat GLenum GLenum const GLint GLenum GLenum const GLdouble GLenum GLenum const GLfloat GLenum GLenum const GLint GLsizei GLuint GLfloat GLuint GLbitfield GLfloat GLint GLuint GLboolean GLenum GLfloat GLenum GLbitfield GLenum GLfloat GLfloat GLint GLint const GLfloat GLenum GLfloat GLfloat GLint GLint GLfloat GLfloat GLint GLint const GLfloat GLint GLfloat GLfloat GLint GLfloat GLfloat GLint GLfloat GLfloat const GLdouble const GLfloat const GLdouble const GLfloat GLint i
Definition: glfuncs.h:248
#define INSIDE_BEGIN_END(CTX)
Definition: macros.h:135
Definition: send.c:48
#define CLAMP(f, min, max)
Definition: tif_color.c:177