u_sampler.c revision 4c7001462607e6e99e474d6271dd481d3f8f201c 
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
33static void
34default_template(struct pipe_sampler_view *view,
35                 const struct pipe_resource *texture,
36                 enum pipe_format format,
37                 unsigned expand_green_blue)
38{
39   /* XXX: Check if format is compatible with texture->format.
40    */
41
42   view->format = format;
43   view->u.tex.first_level = 0;
44   view->u.tex.last_level = texture->last_level;
45   view->u.tex.first_layer = 0;
46   view->u.tex.last_layer = texture->target == PIPE_TEXTURE_3D ?
47                               texture->depth0 - 1 : texture->array_size - 1;
48   view->swizzle_r = PIPE_SWIZZLE_RED;
49   view->swizzle_g = PIPE_SWIZZLE_GREEN;
50   view->swizzle_b = PIPE_SWIZZLE_BLUE;
51   view->swizzle_a = PIPE_SWIZZLE_ALPHA;
52
53   /* Override default green and blue component expansion to the requested
54    * one.
55    *
56    * Gallium expands nonexistent components to (0,0,0,1), DX9 expands
57    * to (1,1,1,1).  Since alpha is always expanded to 1, and red is
58    * always present, we only really care about green and blue
59    * components.
60    *
61    * To make it look less hackish, one would have to add
62    * UTIL_FORMAT_SWIZZLE_EXPAND to indicate components for expansion
63    * and then override without exceptions or favoring one component
64    * over another.
65    */
66   if (format != PIPE_FORMAT_A8_UNORM) {
67      const struct util_format_description *desc = util_format_description(format);
68
69      assert(desc);
70      if (desc) {
71         if (desc->swizzle[1] == UTIL_FORMAT_SWIZZLE_0) {
72            view->swizzle_g = expand_green_blue;
73         }
74         if (desc->swizzle[2] == UTIL_FORMAT_SWIZZLE_0) {
75            view->swizzle_b = expand_green_blue;
76         }
77      }
78   }
79}
80
81void
82u_sampler_view_default_template(struct pipe_sampler_view *view,
83                                const struct pipe_resource *texture,
84                                enum pipe_format format)
85{
86   /* Expand to (0, 0, 0, 1) */
87   default_template(view,
88                    texture,
89                    format,
90                    PIPE_SWIZZLE_ZERO);
91}
92
93void
94u_sampler_view_default_dx9_template(struct pipe_sampler_view *view,
95                                    const struct pipe_resource *texture,
96                                    enum pipe_format format)
97{
98   /* Expand to (1, 1, 1, 1) */
99   default_template(view,
100                    texture,
101                    format,
102                    PIPE_SWIZZLE_ONE);
103}
104