1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
|
/*
* Mesa 3-D graphics library
*
* Copyright (C) 1999-2006 Brian Paul All Rights Reserved.
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included
* in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
* OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
* OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
* ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
* OTHER DEALINGS IN THE SOFTWARE.
*/
/**
* \file swrast/s_alpha.c
* \brief Functions to apply alpha test.
*/
#include "main/glheader.h"
#include "main/context.h"
#include "main/macros.h"
#include "s_alpha.h"
#include "s_context.h"
#define ALPHA_TEST(ALPHA, LOOP_CODE) \
do { \
switch (ctx->Color.AlphaFunc) { \
case GL_LESS: \
for (i = 0; i < n; i++) { \
mask[i] &= (ALPHA < ref); \
LOOP_CODE; \
} \
break; \
case GL_LEQUAL: \
for (i = 0; i < n; i++) { \
mask[i] &= (ALPHA <= ref); \
LOOP_CODE; \
} \
break; \
case GL_GEQUAL: \
for (i = 0; i < n; i++) { \
mask[i] &= (ALPHA >= ref); \
LOOP_CODE; \
} \
break; \
case GL_GREATER: \
for (i = 0; i < n; i++) { \
mask[i] &= (ALPHA > ref); \
LOOP_CODE; \
} \
break; \
case GL_NOTEQUAL: \
for (i = 0; i < n; i++) { \
mask[i] &= (ALPHA != ref); \
LOOP_CODE; \
} \
break; \
case GL_EQUAL: \
for (i = 0; i < n; i++) { \
mask[i] &= (ALPHA == ref); \
LOOP_CODE; \
} \
break; \
default: \
_mesa_problem(ctx, "Invalid alpha test in _swrast_alpha_test" ); \
return 0; \
} \
} while (0)
/**
* Perform the alpha test for an array of pixels.
* For pixels that fail the test, mask[i] will be set to 0.
* \return 0 if all pixels in the span failed the alpha test,
* 1 if one or more pixels passed the alpha test.
*/
GLint
_swrast_alpha_test(const struct gl_context *ctx, SWspan *span)
{
const GLuint n = span->end;
GLubyte *mask = span->array->mask;
GLuint i;
if (ctx->Color.AlphaFunc == GL_ALWAYS) {
/* do nothing */
return 1;
}
else if (ctx->Color.AlphaFunc == GL_NEVER) {
/* All pixels failed - caller should check for this return value and
* act accordingly.
*/
span->writeAll = GL_FALSE;
return 0;
}
if (span->arrayMask & SPAN_RGBA) {
/* Use array's alpha values */
if (span->array->ChanType == GL_UNSIGNED_BYTE) {
GLubyte (*rgba)[4] = span->array->rgba8;
GLubyte ref;
CLAMPED_FLOAT_TO_UBYTE(ref, ctx->Color.AlphaRef);
ALPHA_TEST(rgba[i][ACOMP], ;);
}
else if (span->array->ChanType == GL_UNSIGNED_SHORT) {
GLushort (*rgba)[4] = span->array->rgba16;
GLushort ref;
CLAMPED_FLOAT_TO_USHORT(ref, ctx->Color.AlphaRef);
ALPHA_TEST(rgba[i][ACOMP], ;);
}
else {
GLfloat (*rgba)[4] = span->array->attribs[VARYING_SLOT_COL0];
const GLfloat ref = ctx->Color.AlphaRef;
ALPHA_TEST(rgba[i][ACOMP], ;);
}
}
else {
/* Interpolate alpha values */
assert(span->interpMask & SPAN_RGBA);
if (span->array->ChanType == GL_UNSIGNED_BYTE) {
const GLfixed alphaStep = span->alphaStep;
GLfixed alpha = span->alpha;
GLubyte ref;
CLAMPED_FLOAT_TO_UBYTE(ref, ctx->Color.AlphaRef);
ALPHA_TEST(FixedToInt(alpha), alpha += alphaStep);
}
else if (span->array->ChanType == GL_UNSIGNED_SHORT) {
const GLfixed alphaStep = span->alphaStep;
GLfixed alpha = span->alpha;
GLushort ref;
CLAMPED_FLOAT_TO_USHORT(ref, ctx->Color.AlphaRef);
ALPHA_TEST(FixedToInt(alpha), alpha += alphaStep);
}
else {
const GLfloat alphaStep = FixedToFloat(span->alphaStep);
GLfloat alpha = FixedToFloat(span->alpha);
const GLfloat ref = ctx->Color.AlphaRef;
ALPHA_TEST(alpha, alpha += alphaStep);
}
}
span->writeAll = GL_FALSE;
/* XXX examine mask[] values? */
return 1;
}
|
