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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->target = texture->target;
49    view->format = format;
50    view->u.tex.first_level = 0;
51    view->u.tex.last_level = texture->last_level;
52    view->u.tex.first_layer = 0;
53    view->u.tex.last_layer = texture->target == PIPE_TEXTURE_3D ?
54                                texture->depth0 - 1 : texture->array_size - 1;
55    view->swizzle_r = PIPE_SWIZZLE_X;
56    view->swizzle_g = PIPE_SWIZZLE_Y;
57    view->swizzle_b = PIPE_SWIZZLE_Z;
58    view->swizzle_a = PIPE_SWIZZLE_W;
59 
60    /* Override default green and blue component expansion to the requested
61     * one.
62     *
63     * Gallium expands nonexistent components to (0,0,0,1), DX9 expands
64     * to (1,1,1,1).  Since alpha is always expanded to 1, and red is
65     * always present, we only really care about green and blue
66     * components.
67     *
68     * To make it look less hackish, one would have to add
69     * PIPE_SWIZZLE_EXPAND to indicate components for expansion
70     * and then override without exceptions or favoring one component
71     * over another.
72     */
73    if (format != PIPE_FORMAT_A8_UNORM) {
74       const struct util_format_description *desc = util_format_description(format);
75 
76       assert(desc);
77       if (desc) {
78          if (desc->swizzle[1] == PIPE_SWIZZLE_0) {
79             view->swizzle_g = expand_green_blue;
80          }
81          if (desc->swizzle[2] == PIPE_SWIZZLE_0) {
82             view->swizzle_b = expand_green_blue;
83          }
84       }
85    }
86 }
87 
88 void
u_sampler_view_default_template(struct pipe_sampler_view * view,const struct pipe_resource * texture,enum pipe_format format)89 u_sampler_view_default_template(struct pipe_sampler_view *view,
90                                 const struct pipe_resource *texture,
91                                 enum pipe_format format)
92 {
93    /* Expand to (0, 0, 0, 1) */
94    default_template(view,
95                     texture,
96                     format,
97                     PIPE_SWIZZLE_0);
98 }
99 
100 void
u_sampler_view_default_dx9_template(struct pipe_sampler_view * view,const struct pipe_resource * texture,enum pipe_format format)101 u_sampler_view_default_dx9_template(struct pipe_sampler_view *view,
102                                     const struct pipe_resource *texture,
103                                     enum pipe_format format)
104 {
105    /* Expand to (1, 1, 1, 1) */
106    default_template(view,
107                     texture,
108                     format,
109                     PIPE_SWIZZLE_1);
110 }
111