1/**************************************************************************
2 *
3 * Copyright 2002 VMware, Inc.
4 * Copyright 2011 Dave Airlie (ARB_vertex_type_2_10_10_10_rev support)
5 * Copyright 2020 Advanced Micro Devices, Inc.
6 * All Rights Reserved.
7 *
8 * Permission is hereby granted, free of charge, to any person obtaining a
9 * copy of this software and associated documentation files (the
10 * "Software"), to deal in the Software without restriction, including
11 * without limitation the rights to use, copy, modify, merge, publish,
12 * distribute, sub license, and/or sell copies of the Software, and to
13 * permit persons to whom the Software is furnished to do so, subject to
14 * the following conditions:
15 *
16 * The above copyright notice and this permission notice (including the
17 * next paragraph) shall be included in all copies or substantial portions
18 * of the Software.
19 *
20 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
21 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
22 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.
23 * IN NO EVENT SHALL VMWARE AND/OR ITS SUPPLIERS BE LIABLE FOR
24 * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
25 * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
26 * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
27 *
28 **************************************************************************/
29
30#ifndef VBO_UTIL_H
31#define VBO_UTIL_H
32
33#include "main/mtypes.h"
34
35static inline float conv_ui10_to_norm_float(unsigned ui10)
36{
37   return ui10 / 1023.0f;
38}
39
40static inline float conv_ui2_to_norm_float(unsigned ui2)
41{
42   return ui2 / 3.0f;
43}
44
45struct attr_bits_10 {signed int x:10;};
46struct attr_bits_2 {signed int x:2;};
47
48static inline float conv_i10_to_i(int i10)
49{
50   struct attr_bits_10 val;
51   val.x = i10;
52   return (float)val.x;
53}
54
55static inline float conv_i2_to_i(int i2)
56{
57   struct attr_bits_2 val;
58   val.x = i2;
59   return (float)val.x;
60}
61
62static inline float conv_i10_to_norm_float(const struct gl_context *ctx, int i10)
63{
64   struct attr_bits_10 val;
65   val.x = i10;
66
67   /* Traditionally, OpenGL has had two equations for converting from
68    * normalized fixed-point data to floating-point data.  In the OpenGL 3.2
69    * specification, these are equations 2.2 and 2.3, respectively:
70    *
71    *    f = (2c + 1)/(2^b - 1).                                (2.2)
72    *
73    * Comments below this equation state: "In general, this representation is
74    * used for signed normalized fixed-point parameters in GL commands, such
75    * as vertex attribute values."  Which is what we're doing here.
76    *
77    *    f = max{c/(2^(b-1) - 1), -1.0}                         (2.3)
78    *
79    * Comments below this equation state: "In general, this representation is
80    * used for signed normalized fixed-point texture or floating point values."
81    *
82    * OpenGL 4.2+ and ES 3.0 remedy this and state that equation 2.3 (above)
83    * is used in every case.  They remove equation 2.2 completely.
84    */
85   if (_mesa_is_gles3(ctx) ||
86       (_mesa_is_desktop_gl(ctx) && ctx->Version >= 42)) {
87      /* Equation 2.3 above. */
88      float f = ((float) val.x) / 511.0F;
89      return MAX2(f, -1.0f);
90   } else {
91      /* Equation 2.2 above. */
92      return (2.0F * (float)val.x + 1.0F) * (1.0F  / 1023.0F);
93   }
94}
95
96static inline float conv_i2_to_norm_float(const struct gl_context *ctx, int i2)
97{
98   struct attr_bits_2 val;
99   val.x = i2;
100
101   if (_mesa_is_gles3(ctx) ||
102       (_mesa_is_desktop_gl(ctx) && ctx->Version >= 42)) {
103      /* Equation 2.3 above. */
104      float f = (float) val.x;
105      return MAX2(f, -1.0f);
106   } else {
107      /* Equation 2.2 above. */
108      return (2.0F * (float)val.x + 1.0F) * (1.0F / 3.0F);
109   }
110}
111
112#define ERROR_IF_NOT_PACKED_TYPE(ctx, type, func) \
113   if (type != GL_INT_2_10_10_10_REV && type != GL_UNSIGNED_INT_2_10_10_10_REV) { \
114      _mesa_error(ctx, GL_INVALID_ENUM, "%s(type)", func); \
115      return; \
116   }
117
118/* Extended version of ERROR_IF_NOT_PACKED_TYPE which also
119 * accepts GL_UNSIGNED_INT_10F_11F_11F_REV.
120 *
121 * Only used for VertexAttribP[123]ui[v]; VertexAttribP4* cannot use this type,
122 * and neither can legacy vertex attribs.
123 */
124#define ERROR_IF_NOT_PACKED_TYPE_EXT(ctx, type, func) \
125   if (type != GL_INT_2_10_10_10_REV && type != GL_UNSIGNED_INT_2_10_10_10_REV && \
126       type != GL_UNSIGNED_INT_10F_11F_11F_REV) { \
127      _mesa_error(ctx, GL_INVALID_ENUM, "%s(type)", func); \
128      return; \
129   }
130
131#endif
132