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_TESS_CTRL = 1,
  40    MESA_SHADER_TESS_EVAL = 2,
  41    MESA_SHADER_GEOMETRY = 3,
  42    MESA_SHADER_FRAGMENT = 4,
  43    MESA_SHADER_COMPUTE = 5,
  44 } gl_shader_stage;
  45
  46 #define MESA_SHADER_STAGES (MESA_SHADER_COMPUTE + 1)
  47
  48 /**
  49  * Bitflags for system values.
  50  */
  51 #define SYSTEM_BIT_SAMPLE_ID ((uint64_t)1 << SYSTEM_VALUE_SAMPLE_ID)
  52 #define SYSTEM_BIT_SAMPLE_POS ((uint64_t)1 << SYSTEM_VALUE_SAMPLE_POS)
  53 #define SYSTEM_BIT_SAMPLE_MASK_IN ((uint64_t)1 << SYSTEM_VALUE_SAMPLE_MASK_IN)
  54 /**
  55  * If the gl_register_file is PROGRAM_SYSTEM_VALUE, the register index will be
  56  * one of these values.  If a NIR variable's mode is nir_var_system_value, it
  57  * will be one of these values.
  58  */
  59 typedef enum
  60 {
  61    /**
  62     * \name Vertex shader system values
  63     */
  64    /*@{*/
  65    /**
  66     * OpenGL-style vertex ID.
  67     *
  68     * Section 2.11.7 (Shader Execution), subsection Shader Inputs, of the
  69     * OpenGL 3.3 core profile spec says:
  70     *
  71     *     "gl_VertexID holds the integer index i implicitly passed by
  72     *     DrawArrays or one of the other drawing commands defined in section
  73     *     2.8.3."
  74     *
  75     * Section 2.8.3 (Drawing Commands) of the same spec says:
  76     *
  77     *     "The commands....are equivalent to the commands with the same base
  78     *     name (without the BaseVertex suffix), except that the ith element
  79     *     transferred by the corresponding draw call will be taken from
  80     *     element indices[i] + basevertex of each enabled array."
  81     *
  82     * Additionally, the overview in the GL_ARB_shader_draw_parameters spec
  83     * says:
  84     *
  85     *     "In unextended GL, vertex shaders have inputs named gl_VertexID and
  86     *     gl_InstanceID, which contain, respectively the index of the vertex
  87     *     and instance. The value of gl_VertexID is the implicitly passed
  88     *     index of the vertex being processed, which includes the value of
  89     *     baseVertex, for those commands that accept it."
  90     *
  91     * gl_VertexID gets basevertex added in.  This differs from DirectX where
  92     * SV_VertexID does \b not get basevertex added in.
  93     *
  94     * \note
  95     * If all system values are available, \c SYSTEM_VALUE_VERTEX_ID will be
  96     * equal to \c SYSTEM_VALUE_VERTEX_ID_ZERO_BASE plus
  97     * \c SYSTEM_VALUE_BASE_VERTEX.
  98     *
  99     * \sa SYSTEM_VALUE_VERTEX_ID_ZERO_BASE, SYSTEM_VALUE_BASE_VERTEX
 100     */
 101    SYSTEM_VALUE_VERTEX_ID,
 102
 103    /**
 104     * Instanced ID as supplied to gl_InstanceID
 105     *
 106     * Values assigned to gl_InstanceID always begin with zero, regardless of
 107     * the value of baseinstance.
 108     *
 109     * Section 11.1.3.9 (Shader Inputs) of the OpenGL 4.4 core profile spec
 110     * says:
 111     *
 112     *     "gl_InstanceID holds the integer instance number of the current
 113     *     primitive in an instanced draw call (see section 10.5)."
 114     *
 115     * Through a big chain of pseudocode, section 10.5 describes that
 116     * baseinstance is not counted by gl_InstanceID.  In that section, notice
 117     *
 118     *     "If an enabled vertex attribute array is instanced (it has a
 119     *     non-zero divisor as specified by VertexAttribDivisor), the element
 120     *     index that is transferred to the GL, for all vertices, is given by
 121     *
 122     *         floor(instance/divisor) + baseinstance
 123     *
 124     *     If an array corresponding to an attribute required by a vertex
 125     *     shader is not enabled, then the corresponding element is taken from
 126     *     the current attribute state (see section 10.2)."
 127     *
 128     * Note that baseinstance is \b not included in the value of instance.
 129     */
 130    SYSTEM_VALUE_INSTANCE_ID,
 131
 132    /**
 133     * DirectX-style vertex ID.
 134     *
 135     * Unlike \c SYSTEM_VALUE_VERTEX_ID, this system value does \b not include
 136     * the value of basevertex.
 137     *
 138     * \sa SYSTEM_VALUE_VERTEX_ID, SYSTEM_VALUE_BASE_VERTEX
 139     */
 140    SYSTEM_VALUE_VERTEX_ID_ZERO_BASE,
 141
 142    /**
 143     * Value of \c basevertex passed to \c glDrawElementsBaseVertex and similar
 144     * functions.
 145     *
 146     * \sa SYSTEM_VALUE_VERTEX_ID, SYSTEM_VALUE_VERTEX_ID_ZERO_BASE
 147     */
 148    SYSTEM_VALUE_BASE_VERTEX,
 149    /*@}*/
 150
 151    /**
 152     * \name Geometry shader system values
 153     */
 154    /*@{*/
 155    SYSTEM_VALUE_INVOCATION_ID,  /**< (Also in Tessellation Control shader) */
 156    /*@}*/
 157
 158    /**
 159     * \name Fragment shader system values
 160     */
 161    /*@{*/
 162    SYSTEM_VALUE_FRONT_FACE,     /**< (not done yet) */
 163    SYSTEM_VALUE_SAMPLE_ID,
 164    SYSTEM_VALUE_SAMPLE_POS,
 165    SYSTEM_VALUE_SAMPLE_MASK_IN,
 166    /*@}*/
 167
 168    /**
 169     * \name Tessellation Evaluation shader system values
 170     */
 171    /*@{*/
 172    SYSTEM_VALUE_TESS_COORD,
 173    SYSTEM_VALUE_VERTICES_IN,    /**< Tessellation vertices in input patch */
 174    SYSTEM_VALUE_PRIMITIVE_ID,   /**< (currently not used by GS) */
 175    SYSTEM_VALUE_TESS_LEVEL_OUTER, /**< TES input */
 176    SYSTEM_VALUE_TESS_LEVEL_INNER, /**< TES input */
 177    /*@}*/
 178
 179    SYSTEM_VALUE_MAX             /**< Number of values */
 180 } gl_system_value;
 181
 182
 183 /**
 184  * The possible interpolation qualifiers that can be applied to a fragment
 185  * shader input in GLSL.
 186  *
 187  * Note: INTERP_QUALIFIER_NONE must be 0 so that memsetting the
 188  * gl_fragment_program data structure to 0 causes the default behavior.
 189  */
 190 enum glsl_interp_qualifier
 191 {
 192    INTERP_QUALIFIER_NONE = 0,
 193    INTERP_QUALIFIER_SMOOTH,
 194    INTERP_QUALIFIER_FLAT,
 195    INTERP_QUALIFIER_NOPERSPECTIVE,
 196    INTERP_QUALIFIER_COUNT /**< Number of interpolation qualifiers */
 197 };
 198
 199
 200 #endif /* SHADER_ENUMS_H */