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1 /**************************************************************************
2  *
3  * Copyright 2010 VMware, Inc.
4  * All Rights Reserved.
5  *
6  * Permission is hereby granted, free of charge, to any person obtaining a
7  * copy of this software and associated documentation files (the
8  * "Software"), to deal in the Software without restriction, including
9  * without limitation the rights to use, copy, modify, merge, publish,
10  * distribute, sub license, and/or sell copies of the Software, and to
11  * permit persons to whom the Software is furnished to do so, subject to
12  * the following conditions:
13  *
14  * The above copyright notice and this permission notice (including the
15  * next paragraph) shall be included in all copies or substantial portions
16  * of the Software.
17  *
18  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
19  * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
20  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.
21  * IN NO EVENT SHALL VMWARE AND/OR ITS SUPPLIERS BE LIABLE FOR
22  * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
23  * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
24  * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
25  *
26  **************************************************************************/
27 
28 
29 #include "u_format.h"
30 #include "u_sampler.h"
31 
32 
33 /**
34  * Initialize a pipe_sampler_view.  'view' is considered to have
35  * uninitialized contents.
36  */
37 static void
default_template(struct pipe_sampler_view * view,const struct pipe_resource * texture,enum pipe_format format,unsigned expand_green_blue)38 default_template(struct pipe_sampler_view *view,
39                  const struct pipe_resource *texture,
40                  enum pipe_format format,
41                  unsigned expand_green_blue)
42 {
43    memset(view, 0, sizeof(*view));
44 
45    /* XXX: Check if format is compatible with texture->format.
46     */
47 
48    view->format = format;
49    view->u.tex.first_level = 0;
50    view->u.tex.last_level = texture->last_level;
51    view->u.tex.first_layer = 0;
52    view->u.tex.last_layer = texture->target == PIPE_TEXTURE_3D ?
53                                texture->depth0 - 1 : texture->array_size - 1;
54    view->swizzle_r = PIPE_SWIZZLE_RED;
55    view->swizzle_g = PIPE_SWIZZLE_GREEN;
56    view->swizzle_b = PIPE_SWIZZLE_BLUE;
57    view->swizzle_a = PIPE_SWIZZLE_ALPHA;
58 
59    /* Override default green and blue component expansion to the requested
60     * one.
61     *
62     * Gallium expands nonexistent components to (0,0,0,1), DX9 expands
63     * to (1,1,1,1).  Since alpha is always expanded to 1, and red is
64     * always present, we only really care about green and blue
65     * components.
66     *
67     * To make it look less hackish, one would have to add
68     * UTIL_FORMAT_SWIZZLE_EXPAND to indicate components for expansion
69     * and then override without exceptions or favoring one component
70     * over another.
71     */
72    if (format != PIPE_FORMAT_A8_UNORM) {
73       const struct util_format_description *desc = util_format_description(format);
74 
75       assert(desc);
76       if (desc) {
77          if (desc->swizzle[1] == UTIL_FORMAT_SWIZZLE_0) {
78             view->swizzle_g = expand_green_blue;
79          }
80          if (desc->swizzle[2] == UTIL_FORMAT_SWIZZLE_0) {
81             view->swizzle_b = expand_green_blue;
82          }
83       }
84    }
85 }
86 
87 void
u_sampler_view_default_template(struct pipe_sampler_view * view,const struct pipe_resource * texture,enum pipe_format format)88 u_sampler_view_default_template(struct pipe_sampler_view *view,
89                                 const struct pipe_resource *texture,
90                                 enum pipe_format format)
91 {
92    /* Expand to (0, 0, 0, 1) */
93    default_template(view,
94                     texture,
95                     format,
96                     PIPE_SWIZZLE_ZERO);
97 }
98 
99 void
u_sampler_view_default_dx9_template(struct pipe_sampler_view * view,const struct pipe_resource * texture,enum pipe_format format)100 u_sampler_view_default_dx9_template(struct pipe_sampler_view *view,
101                                     const struct pipe_resource *texture,
102                                     enum pipe_format format)
103 {
104    /* Expand to (1, 1, 1, 1) */
105    default_template(view,
106                     texture,
107                     format,
108                     PIPE_SWIZZLE_ONE);
109 }
110