src/mesa/vbo/vbo_util.h

   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
  35 static inline float conv_ui10_to_norm_float(unsigned ui10)
  36 {
  37    return ui10 / 1023.0f;
  38 }
  39
  40 static inline float conv_ui2_to_norm_float(unsigned ui2)
  41 {
  42    return ui2 / 3.0f;
  43 }
  44
  45 struct attr_bits_10 {signed int x:10;};
  46 struct attr_bits_2 {signed int x:2;};
  47
  48 static 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
  55 static 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
  62 static 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
  96 static 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