src/glsl/shader_enums.h

   1 /*
   2  * Mesa 3-D graphics library
   3  *
   4  * Copyright (C) 1999-2008  Brian Paul   All Rights Reserved.
   5  * Copyright (C) 2009  VMware, Inc.  All Rights Reserved.
   6  *
   7  * Permission is hereby granted, free of charge, to any person obtaining a
   8  * copy of this software and associated documentation files (the "Software"),
   9  * to deal in the Software without restriction, including without limitation
  10  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
  11  * and/or sell copies of the Software, and to permit persons to whom the
  12  * Software is furnished to do so, subject to the following conditions:
  13  *
  14  * The above copyright notice and this permission notice shall be included
  15  * in all copies or substantial portions of the Software.
  16  *
  17  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
  18  * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  19  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  20  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
  21  * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
  22  * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
  23  * OTHER DEALINGS IN THE SOFTWARE.
  24  */
  25
  26 #ifndef SHADER_ENUMS_H
  27 #define SHADER_ENUMS_H
  28
  29 /**
  30  * Shader stages. Note that these will become 5 with tessellation.
  31  *
  32  * The order must match how shaders are ordered in the pipeline.
  33  * The GLSL linker assumes that if i<j, then the j-th shader is
  34  * executed later than the i-th shader.
  35  */
  36 typedef enum
  37 {
  38    MESA_SHADER_VERTEX = 0,
  39    MESA_SHADER_GEOMETRY = 1,
  40    MESA_SHADER_FRAGMENT = 2,
  41    MESA_SHADER_COMPUTE = 3,
  42 } gl_shader_stage;
  43
  44 #define MESA_SHADER_STAGES (MESA_SHADER_COMPUTE + 1)
  45
  46 /**
  47  * Bitflags for system values.
  48  */
  49 #define SYSTEM_BIT_SAMPLE_ID ((uint64_t)1 << SYSTEM_VALUE_SAMPLE_ID)
  50 #define SYSTEM_BIT_SAMPLE_POS ((uint64_t)1 << SYSTEM_VALUE_SAMPLE_POS)
  51 #define SYSTEM_BIT_SAMPLE_MASK_IN ((uint64_t)1 << SYSTEM_VALUE_SAMPLE_MASK_IN)
  52 /**
  53  * If the gl_register_file is PROGRAM_SYSTEM_VALUE, the register index will be
  54  * one of these values.  If a NIR variable's mode is nir_var_system_value, it
  55  * will be one of these values.
  56  */
  57 typedef enum
  58 {
  59    /**
  60     * \name Vertex shader system values
  61     */
  62    /*@{*/
  63    /**
  64     * OpenGL-style vertex ID.
  65     *
  66     * Section 2.11.7 (Shader Execution), subsection Shader Inputs, of the
  67     * OpenGL 3.3 core profile spec says:
  68     *
  69     *     "gl_VertexID holds the integer index i implicitly passed by
  70     *     DrawArrays or one of the other drawing commands defined in section
  71     *     2.8.3."
  72     *
  73     * Section 2.8.3 (Drawing Commands) of the same spec says:
  74     *
  75     *     "The commands....are equivalent to the commands with the same base
  76     *     name (without the BaseVertex suffix), except that the ith element
  77     *     transferred by the corresponding draw call will be taken from
  78     *     element indices[i] + basevertex of each enabled array."
  79     *
  80     * Additionally, the overview in the GL_ARB_shader_draw_parameters spec
  81     * says:
  82     *
  83     *     "In unextended GL, vertex shaders have inputs named gl_VertexID and
  84     *     gl_InstanceID, which contain, respectively the index of the vertex
  85     *     and instance. The value of gl_VertexID is the implicitly passed
  86     *     index of the vertex being processed, which includes the value of
  87     *     baseVertex, for those commands that accept it."
  88     *
  89     * gl_VertexID gets basevertex added in.  This differs from DirectX where
  90     * SV_VertexID does \b not get basevertex added in.
  91     *
  92     * \note
  93     * If all system values are available, \c SYSTEM_VALUE_VERTEX_ID will be
  94     * equal to \c SYSTEM_VALUE_VERTEX_ID_ZERO_BASE plus
  95     * \c SYSTEM_VALUE_BASE_VERTEX.
  96     *
  97     * \sa SYSTEM_VALUE_VERTEX_ID_ZERO_BASE, SYSTEM_VALUE_BASE_VERTEX
  98     */
  99    SYSTEM_VALUE_VERTEX_ID,
 100
 101    /**
 102     * Instanced ID as supplied to gl_InstanceID
 103     *
 104     * Values assigned to gl_InstanceID always begin with zero, regardless of
 105     * the value of baseinstance.
 106     *
 107     * Section 11.1.3.9 (Shader Inputs) of the OpenGL 4.4 core profile spec
 108     * says:
 109     *
 110     *     "gl_InstanceID holds the integer instance number of the current
 111     *     primitive in an instanced draw call (see section 10.5)."
 112     *
 113     * Through a big chain of pseudocode, section 10.5 describes that
 114     * baseinstance is not counted by gl_InstanceID.  In that section, notice
 115     *
 116     *     "If an enabled vertex attribute array is instanced (it has a
 117     *     non-zero divisor as specified by VertexAttribDivisor), the element
 118     *     index that is transferred to the GL, for all vertices, is given by
 119     *
 120     *         floor(instance/divisor) + baseinstance
 121     *
 122     *     If an array corresponding to an attribute required by a vertex
 123     *     shader is not enabled, then the corresponding element is taken from
 124     *     the current attribute state (see section 10.2)."
 125     *
 126     * Note that baseinstance is \b not included in the value of instance.
 127     */
 128    SYSTEM_VALUE_INSTANCE_ID,
 129
 130    /**
 131     * DirectX-style vertex ID.
 132     *
 133     * Unlike \c SYSTEM_VALUE_VERTEX_ID, this system value does \b not include
 134     * the value of basevertex.
 135     *
 136     * \sa SYSTEM_VALUE_VERTEX_ID, SYSTEM_VALUE_BASE_VERTEX
 137     */
 138    SYSTEM_VALUE_VERTEX_ID_ZERO_BASE,
 139
 140    /**
 141     * Value of \c basevertex passed to \c glDrawElementsBaseVertex and similar
 142     * functions.
 143     *
 144     * \sa SYSTEM_VALUE_VERTEX_ID, SYSTEM_VALUE_VERTEX_ID_ZERO_BASE
 145     */
 146    SYSTEM_VALUE_BASE_VERTEX,
 147    /*@}*/
 148
 149    /**
 150     * \name Geometry shader system values
 151     */
 152    /*@{*/
 153    SYSTEM_VALUE_INVOCATION_ID,
 154    /*@}*/
 155
 156    /**
 157     * \name Fragment shader system values
 158     */
 159    /*@{*/
 160    SYSTEM_VALUE_FRONT_FACE,     /**< (not done yet) */
 161    SYSTEM_VALUE_SAMPLE_ID,
 162    SYSTEM_VALUE_SAMPLE_POS,
 163    SYSTEM_VALUE_SAMPLE_MASK_IN,
 164    /*@}*/
 165
 166    SYSTEM_VALUE_MAX             /**< Number of values */
 167 } gl_system_value;
 168
 169
 170 /**
 171  * The possible interpolation qualifiers that can be applied to a fragment
 172  * shader input in GLSL.
 173  *
 174  * Note: INTERP_QUALIFIER_NONE must be 0 so that memsetting the
 175  * gl_fragment_program data structure to 0 causes the default behavior.
 176  */
 177 enum glsl_interp_qualifier
 178 {
 179    INTERP_QUALIFIER_NONE = 0,
 180    INTERP_QUALIFIER_SMOOTH,
 181    INTERP_QUALIFIER_FLAT,
 182    INTERP_QUALIFIER_NOPERSPECTIVE,
 183    INTERP_QUALIFIER_COUNT /**< Number of interpolation qualifiers */
 184 };
 185
 186
 187 #endif /* SHADER_ENUMS_H */