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      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 #ifdef __cplusplus
     30 extern "C" {
     31 #endif
     32 
     33 /**
     34  * Shader stages.
     35  *
     36  * The order must match how shaders are ordered in the pipeline.
     37  * The GLSL linker assumes that if i<j, then the j-th shader is
     38  * executed later than the i-th shader.
     39  */
     40 typedef enum
     41 {
     42    MESA_SHADER_NONE = -1,
     43    MESA_SHADER_VERTEX = 0,
     44    MESA_SHADER_TESS_CTRL = 1,
     45    MESA_SHADER_TESS_EVAL = 2,
     46    MESA_SHADER_GEOMETRY = 3,
     47    MESA_SHADER_FRAGMENT = 4,
     48    MESA_SHADER_COMPUTE = 5,
     49 } gl_shader_stage;
     50 
     51 const char *gl_shader_stage_name(gl_shader_stage stage);
     52 
     53 /**
     54  * Translate a gl_shader_stage to a short shader stage name for debug
     55  * printouts and error messages.
     56  */
     57 const char *_mesa_shader_stage_to_string(unsigned stage);
     58 
     59 /**
     60  * Translate a gl_shader_stage to a shader stage abbreviation (VS, GS, FS)
     61  * for debug printouts and error messages.
     62  */
     63 const char *_mesa_shader_stage_to_abbrev(unsigned stage);
     64 
     65 #define MESA_SHADER_STAGES (MESA_SHADER_COMPUTE + 1)
     66 
     67 
     68 /**
     69  * Indexes for vertex program attributes.
     70  * GL_NV_vertex_program aliases generic attributes over the conventional
     71  * attributes.  In GL_ARB_vertex_program shader the aliasing is optional.
     72  * In GL_ARB_vertex_shader / OpenGL 2.0 the aliasing is disallowed (the
     73  * generic attributes are distinct/separate).
     74  */
     75 typedef enum
     76 {
     77    VERT_ATTRIB_POS,
     78    VERT_ATTRIB_NORMAL,
     79    VERT_ATTRIB_COLOR0,
     80    VERT_ATTRIB_COLOR1,
     81    VERT_ATTRIB_FOG,
     82    VERT_ATTRIB_COLOR_INDEX,
     83    VERT_ATTRIB_EDGEFLAG,
     84    VERT_ATTRIB_TEX0,
     85    VERT_ATTRIB_TEX1,
     86    VERT_ATTRIB_TEX2,
     87    VERT_ATTRIB_TEX3,
     88    VERT_ATTRIB_TEX4,
     89    VERT_ATTRIB_TEX5,
     90    VERT_ATTRIB_TEX6,
     91    VERT_ATTRIB_TEX7,
     92    VERT_ATTRIB_POINT_SIZE,
     93    VERT_ATTRIB_GENERIC0,
     94    VERT_ATTRIB_GENERIC1,
     95    VERT_ATTRIB_GENERIC2,
     96    VERT_ATTRIB_GENERIC3,
     97    VERT_ATTRIB_GENERIC4,
     98    VERT_ATTRIB_GENERIC5,
     99    VERT_ATTRIB_GENERIC6,
    100    VERT_ATTRIB_GENERIC7,
    101    VERT_ATTRIB_GENERIC8,
    102    VERT_ATTRIB_GENERIC9,
    103    VERT_ATTRIB_GENERIC10,
    104    VERT_ATTRIB_GENERIC11,
    105    VERT_ATTRIB_GENERIC12,
    106    VERT_ATTRIB_GENERIC13,
    107    VERT_ATTRIB_GENERIC14,
    108    VERT_ATTRIB_GENERIC15,
    109    VERT_ATTRIB_MAX
    110 } gl_vert_attrib;
    111 
    112 const char *gl_vert_attrib_name(gl_vert_attrib attrib);
    113 
    114 /**
    115  * Symbolic constats to help iterating over
    116  * specific blocks of vertex attributes.
    117  *
    118  * VERT_ATTRIB_FF
    119  *   includes all fixed function attributes as well as
    120  *   the aliased GL_NV_vertex_program shader attributes.
    121  * VERT_ATTRIB_TEX
    122  *   include the classic texture coordinate attributes.
    123  *   Is a subset of VERT_ATTRIB_FF.
    124  * VERT_ATTRIB_GENERIC
    125  *   include the OpenGL 2.0+ GLSL generic shader attributes.
    126  *   These alias the generic GL_ARB_vertex_shader attributes.
    127  */
    128 #define VERT_ATTRIB_FF(i)           (VERT_ATTRIB_POS + (i))
    129 #define VERT_ATTRIB_FF_MAX          VERT_ATTRIB_GENERIC0
    130 
    131 #define VERT_ATTRIB_TEX(i)          (VERT_ATTRIB_TEX0 + (i))
    132 #define VERT_ATTRIB_TEX_MAX         MAX_TEXTURE_COORD_UNITS
    133 
    134 #define VERT_ATTRIB_GENERIC(i)      (VERT_ATTRIB_GENERIC0 + (i))
    135 #define VERT_ATTRIB_GENERIC_MAX     MAX_VERTEX_GENERIC_ATTRIBS
    136 
    137 /**
    138  * Bitflags for vertex attributes.
    139  * These are used in bitfields in many places.
    140  */
    141 /*@{*/
    142 #define VERT_BIT_POS             BITFIELD_BIT(VERT_ATTRIB_POS)
    143 #define VERT_BIT_NORMAL          BITFIELD_BIT(VERT_ATTRIB_NORMAL)
    144 #define VERT_BIT_COLOR0          BITFIELD_BIT(VERT_ATTRIB_COLOR0)
    145 #define VERT_BIT_COLOR1          BITFIELD_BIT(VERT_ATTRIB_COLOR1)
    146 #define VERT_BIT_FOG             BITFIELD_BIT(VERT_ATTRIB_FOG)
    147 #define VERT_BIT_COLOR_INDEX     BITFIELD_BIT(VERT_ATTRIB_COLOR_INDEX)
    148 #define VERT_BIT_EDGEFLAG        BITFIELD_BIT(VERT_ATTRIB_EDGEFLAG)
    149 #define VERT_BIT_TEX0            BITFIELD_BIT(VERT_ATTRIB_TEX0)
    150 #define VERT_BIT_TEX1            BITFIELD_BIT(VERT_ATTRIB_TEX1)
    151 #define VERT_BIT_TEX2            BITFIELD_BIT(VERT_ATTRIB_TEX2)
    152 #define VERT_BIT_TEX3            BITFIELD_BIT(VERT_ATTRIB_TEX3)
    153 #define VERT_BIT_TEX4            BITFIELD_BIT(VERT_ATTRIB_TEX4)
    154 #define VERT_BIT_TEX5            BITFIELD_BIT(VERT_ATTRIB_TEX5)
    155 #define VERT_BIT_TEX6            BITFIELD_BIT(VERT_ATTRIB_TEX6)
    156 #define VERT_BIT_TEX7            BITFIELD_BIT(VERT_ATTRIB_TEX7)
    157 #define VERT_BIT_POINT_SIZE      BITFIELD_BIT(VERT_ATTRIB_POINT_SIZE)
    158 #define VERT_BIT_GENERIC0        BITFIELD_BIT(VERT_ATTRIB_GENERIC0)
    159 
    160 #define VERT_BIT(i)              BITFIELD_BIT(i)
    161 #define VERT_BIT_ALL             BITFIELD_RANGE(0, VERT_ATTRIB_MAX)
    162 
    163 #define VERT_BIT_FF(i)           VERT_BIT(i)
    164 #define VERT_BIT_FF_ALL          BITFIELD_RANGE(0, VERT_ATTRIB_FF_MAX)
    165 #define VERT_BIT_TEX(i)          VERT_BIT(VERT_ATTRIB_TEX(i))
    166 #define VERT_BIT_TEX_ALL         \
    167    BITFIELD_RANGE(VERT_ATTRIB_TEX(0), VERT_ATTRIB_TEX_MAX)
    168 
    169 #define VERT_BIT_GENERIC(i)      VERT_BIT(VERT_ATTRIB_GENERIC(i))
    170 #define VERT_BIT_GENERIC_ALL     \
    171    BITFIELD_RANGE(VERT_ATTRIB_GENERIC(0), VERT_ATTRIB_GENERIC_MAX)
    172 /*@}*/
    173 
    174 #define MAX_VARYING 32 /**< number of float[4] vectors */
    175 
    176 /**
    177  * Indexes for vertex shader outputs, geometry shader inputs/outputs, and
    178  * fragment shader inputs.
    179  *
    180  * Note that some of these values are not available to all pipeline stages.
    181  *
    182  * When this enum is updated, the following code must be updated too:
    183  * - vertResults (in prog_print.c's arb_output_attrib_string())
    184  * - fragAttribs (in prog_print.c's arb_input_attrib_string())
    185  * - _mesa_varying_slot_in_fs()
    186  */
    187 typedef enum
    188 {
    189    VARYING_SLOT_POS,
    190    VARYING_SLOT_COL0, /* COL0 and COL1 must be contiguous */
    191    VARYING_SLOT_COL1,
    192    VARYING_SLOT_FOGC,
    193    VARYING_SLOT_TEX0, /* TEX0-TEX7 must be contiguous */
    194    VARYING_SLOT_TEX1,
    195    VARYING_SLOT_TEX2,
    196    VARYING_SLOT_TEX3,
    197    VARYING_SLOT_TEX4,
    198    VARYING_SLOT_TEX5,
    199    VARYING_SLOT_TEX6,
    200    VARYING_SLOT_TEX7,
    201    VARYING_SLOT_PSIZ, /* Does not appear in FS */
    202    VARYING_SLOT_BFC0, /* Does not appear in FS */
    203    VARYING_SLOT_BFC1, /* Does not appear in FS */
    204    VARYING_SLOT_EDGE, /* Does not appear in FS */
    205    VARYING_SLOT_CLIP_VERTEX, /* Does not appear in FS */
    206    VARYING_SLOT_CLIP_DIST0,
    207    VARYING_SLOT_CLIP_DIST1,
    208    VARYING_SLOT_CULL_DIST0,
    209    VARYING_SLOT_CULL_DIST1,
    210    VARYING_SLOT_PRIMITIVE_ID, /* Does not appear in VS */
    211    VARYING_SLOT_LAYER, /* Appears as VS or GS output */
    212    VARYING_SLOT_VIEWPORT, /* Appears as VS or GS output */
    213    VARYING_SLOT_FACE, /* FS only */
    214    VARYING_SLOT_PNTC, /* FS only */
    215    VARYING_SLOT_TESS_LEVEL_OUTER, /* Only appears as TCS output. */
    216    VARYING_SLOT_TESS_LEVEL_INNER, /* Only appears as TCS output. */
    217    VARYING_SLOT_BOUNDING_BOX0, /* Only appears as TCS output. */
    218    VARYING_SLOT_BOUNDING_BOX1, /* Only appears as TCS output. */
    219    VARYING_SLOT_VIEW_INDEX,
    220    VARYING_SLOT_VAR0, /* First generic varying slot */
    221    /* the remaining are simply for the benefit of gl_varying_slot_name()
    222     * and not to be construed as an upper bound:
    223     */
    224    VARYING_SLOT_VAR1,
    225    VARYING_SLOT_VAR2,
    226    VARYING_SLOT_VAR3,
    227    VARYING_SLOT_VAR4,
    228    VARYING_SLOT_VAR5,
    229    VARYING_SLOT_VAR6,
    230    VARYING_SLOT_VAR7,
    231    VARYING_SLOT_VAR8,
    232    VARYING_SLOT_VAR9,
    233    VARYING_SLOT_VAR10,
    234    VARYING_SLOT_VAR11,
    235    VARYING_SLOT_VAR12,
    236    VARYING_SLOT_VAR13,
    237    VARYING_SLOT_VAR14,
    238    VARYING_SLOT_VAR15,
    239    VARYING_SLOT_VAR16,
    240    VARYING_SLOT_VAR17,
    241    VARYING_SLOT_VAR18,
    242    VARYING_SLOT_VAR19,
    243    VARYING_SLOT_VAR20,
    244    VARYING_SLOT_VAR21,
    245    VARYING_SLOT_VAR22,
    246    VARYING_SLOT_VAR23,
    247    VARYING_SLOT_VAR24,
    248    VARYING_SLOT_VAR25,
    249    VARYING_SLOT_VAR26,
    250    VARYING_SLOT_VAR27,
    251    VARYING_SLOT_VAR28,
    252    VARYING_SLOT_VAR29,
    253    VARYING_SLOT_VAR30,
    254    VARYING_SLOT_VAR31,
    255 } gl_varying_slot;
    256 
    257 
    258 #define VARYING_SLOT_MAX	(VARYING_SLOT_VAR0 + MAX_VARYING)
    259 #define VARYING_SLOT_PATCH0	(VARYING_SLOT_MAX)
    260 #define VARYING_SLOT_TESS_MAX	(VARYING_SLOT_PATCH0 + MAX_VARYING)
    261 #define MAX_VARYINGS_INCL_PATCH (VARYING_SLOT_TESS_MAX - VARYING_SLOT_VAR0)
    262 
    263 const char *gl_varying_slot_name(gl_varying_slot slot);
    264 
    265 /**
    266  * Bitflags for varying slots.
    267  */
    268 /*@{*/
    269 #define VARYING_BIT_POS BITFIELD64_BIT(VARYING_SLOT_POS)
    270 #define VARYING_BIT_COL0 BITFIELD64_BIT(VARYING_SLOT_COL0)
    271 #define VARYING_BIT_COL1 BITFIELD64_BIT(VARYING_SLOT_COL1)
    272 #define VARYING_BIT_FOGC BITFIELD64_BIT(VARYING_SLOT_FOGC)
    273 #define VARYING_BIT_TEX0 BITFIELD64_BIT(VARYING_SLOT_TEX0)
    274 #define VARYING_BIT_TEX1 BITFIELD64_BIT(VARYING_SLOT_TEX1)
    275 #define VARYING_BIT_TEX2 BITFIELD64_BIT(VARYING_SLOT_TEX2)
    276 #define VARYING_BIT_TEX3 BITFIELD64_BIT(VARYING_SLOT_TEX3)
    277 #define VARYING_BIT_TEX4 BITFIELD64_BIT(VARYING_SLOT_TEX4)
    278 #define VARYING_BIT_TEX5 BITFIELD64_BIT(VARYING_SLOT_TEX5)
    279 #define VARYING_BIT_TEX6 BITFIELD64_BIT(VARYING_SLOT_TEX6)
    280 #define VARYING_BIT_TEX7 BITFIELD64_BIT(VARYING_SLOT_TEX7)
    281 #define VARYING_BIT_TEX(U) BITFIELD64_BIT(VARYING_SLOT_TEX0 + (U))
    282 #define VARYING_BITS_TEX_ANY BITFIELD64_RANGE(VARYING_SLOT_TEX0, \
    283                                               MAX_TEXTURE_COORD_UNITS)
    284 #define VARYING_BIT_PSIZ BITFIELD64_BIT(VARYING_SLOT_PSIZ)
    285 #define VARYING_BIT_BFC0 BITFIELD64_BIT(VARYING_SLOT_BFC0)
    286 #define VARYING_BIT_BFC1 BITFIELD64_BIT(VARYING_SLOT_BFC1)
    287 #define VARYING_BIT_EDGE BITFIELD64_BIT(VARYING_SLOT_EDGE)
    288 #define VARYING_BIT_CLIP_VERTEX BITFIELD64_BIT(VARYING_SLOT_CLIP_VERTEX)
    289 #define VARYING_BIT_CLIP_DIST0 BITFIELD64_BIT(VARYING_SLOT_CLIP_DIST0)
    290 #define VARYING_BIT_CLIP_DIST1 BITFIELD64_BIT(VARYING_SLOT_CLIP_DIST1)
    291 #define VARYING_BIT_CULL_DIST0 BITFIELD64_BIT(VARYING_SLOT_CULL_DIST0)
    292 #define VARYING_BIT_CULL_DIST1 BITFIELD64_BIT(VARYING_SLOT_CULL_DIST1)
    293 #define VARYING_BIT_PRIMITIVE_ID BITFIELD64_BIT(VARYING_SLOT_PRIMITIVE_ID)
    294 #define VARYING_BIT_LAYER BITFIELD64_BIT(VARYING_SLOT_LAYER)
    295 #define VARYING_BIT_VIEWPORT BITFIELD64_BIT(VARYING_SLOT_VIEWPORT)
    296 #define VARYING_BIT_FACE BITFIELD64_BIT(VARYING_SLOT_FACE)
    297 #define VARYING_BIT_PNTC BITFIELD64_BIT(VARYING_SLOT_PNTC)
    298 #define VARYING_BIT_TESS_LEVEL_OUTER BITFIELD64_BIT(VARYING_SLOT_TESS_LEVEL_OUTER)
    299 #define VARYING_BIT_TESS_LEVEL_INNER BITFIELD64_BIT(VARYING_SLOT_TESS_LEVEL_INNER)
    300 #define VARYING_BIT_BOUNDING_BOX0 BITFIELD64_BIT(VARYING_SLOT_BOUNDING_BOX0)
    301 #define VARYING_BIT_BOUNDING_BOX1 BITFIELD64_BIT(VARYING_SLOT_BOUNDING_BOX1)
    302 #define VARYING_BIT_VAR(V) BITFIELD64_BIT(VARYING_SLOT_VAR0 + (V))
    303 /*@}*/
    304 
    305 /**
    306  * Bitflags for system values.
    307  */
    308 #define SYSTEM_BIT_SAMPLE_ID ((uint64_t)1 << SYSTEM_VALUE_SAMPLE_ID)
    309 #define SYSTEM_BIT_SAMPLE_POS ((uint64_t)1 << SYSTEM_VALUE_SAMPLE_POS)
    310 #define SYSTEM_BIT_SAMPLE_MASK_IN ((uint64_t)1 << SYSTEM_VALUE_SAMPLE_MASK_IN)
    311 #define SYSTEM_BIT_LOCAL_INVOCATION_ID ((uint64_t)1 << SYSTEM_VALUE_LOCAL_INVOCATION_ID)
    312 
    313 /**
    314  * If the gl_register_file is PROGRAM_SYSTEM_VALUE, the register index will be
    315  * one of these values.  If a NIR variable's mode is nir_var_system_value, it
    316  * will be one of these values.
    317  */
    318 typedef enum
    319 {
    320    /**
    321     * \name System values applicable to all shaders
    322     */
    323    /*@{*/
    324 
    325    /**
    326     * Builtin variables added by GL_ARB_shader_ballot.
    327     */
    328    /*@{*/
    329 
    330    /**
    331     * From the GL_ARB_shader-ballot spec:
    332     *
    333     *    "A sub-group is a collection of invocations which execute in lockstep.
    334     *     The variable <gl_SubGroupSizeARB> is the maximum number of
    335     *     invocations in a sub-group. The maximum <gl_SubGroupSizeARB>
    336     *     supported in this extension is 64."
    337     *
    338     * The spec defines this as a uniform. However, it's highly unlikely that
    339     * implementations actually treat it as a uniform (which is loaded from a
    340     * constant buffer). Most likely, this is an implementation-wide constant,
    341     * or perhaps something that depends on the shader stage.
    342     */
    343    SYSTEM_VALUE_SUBGROUP_SIZE,
    344 
    345    /**
    346     * From the GL_ARB_shader_ballot spec:
    347     *
    348     *    "The variable <gl_SubGroupInvocationARB> holds the index of the
    349     *     invocation within sub-group. This variable is in the range 0 to
    350     *     <gl_SubGroupSizeARB>-1, where <gl_SubGroupSizeARB> is the total
    351     *     number of invocations in a sub-group."
    352     */
    353    SYSTEM_VALUE_SUBGROUP_INVOCATION,
    354 
    355    /**
    356     * From the GL_ARB_shader_ballot spec:
    357     *
    358     *    "The <gl_SubGroup??MaskARB> variables provide a bitmask for all
    359     *     invocations, with one bit per invocation starting with the least
    360     *     significant bit, according to the following table,
    361     *
    362     *       variable               equation for bit values
    363     *       --------------------   ------------------------------------
    364     *       gl_SubGroupEqMaskARB   bit index == gl_SubGroupInvocationARB
    365     *       gl_SubGroupGeMaskARB   bit index >= gl_SubGroupInvocationARB
    366     *       gl_SubGroupGtMaskARB   bit index >  gl_SubGroupInvocationARB
    367     *       gl_SubGroupLeMaskARB   bit index <= gl_SubGroupInvocationARB
    368     *       gl_SubGroupLtMaskARB   bit index <  gl_SubGroupInvocationARB
    369     */
    370    SYSTEM_VALUE_SUBGROUP_EQ_MASK,
    371    SYSTEM_VALUE_SUBGROUP_GE_MASK,
    372    SYSTEM_VALUE_SUBGROUP_GT_MASK,
    373    SYSTEM_VALUE_SUBGROUP_LE_MASK,
    374    SYSTEM_VALUE_SUBGROUP_LT_MASK,
    375    /*@}*/
    376 
    377    /*@}*/
    378 
    379    /**
    380     * \name Vertex shader system values
    381     */
    382    /*@{*/
    383    /**
    384     * OpenGL-style vertex ID.
    385     *
    386     * Section 2.11.7 (Shader Execution), subsection Shader Inputs, of the
    387     * OpenGL 3.3 core profile spec says:
    388     *
    389     *     "gl_VertexID holds the integer index i implicitly passed by
    390     *     DrawArrays or one of the other drawing commands defined in section
    391     *     2.8.3."
    392     *
    393     * Section 2.8.3 (Drawing Commands) of the same spec says:
    394     *
    395     *     "The commands....are equivalent to the commands with the same base
    396     *     name (without the BaseVertex suffix), except that the ith element
    397     *     transferred by the corresponding draw call will be taken from
    398     *     element indices[i] + basevertex of each enabled array."
    399     *
    400     * Additionally, the overview in the GL_ARB_shader_draw_parameters spec
    401     * says:
    402     *
    403     *     "In unextended GL, vertex shaders have inputs named gl_VertexID and
    404     *     gl_InstanceID, which contain, respectively the index of the vertex
    405     *     and instance. The value of gl_VertexID is the implicitly passed
    406     *     index of the vertex being processed, which includes the value of
    407     *     baseVertex, for those commands that accept it."
    408     *
    409     * gl_VertexID gets basevertex added in.  This differs from DirectX where
    410     * SV_VertexID does \b not get basevertex added in.
    411     *
    412     * \note
    413     * If all system values are available, \c SYSTEM_VALUE_VERTEX_ID will be
    414     * equal to \c SYSTEM_VALUE_VERTEX_ID_ZERO_BASE plus
    415     * \c SYSTEM_VALUE_BASE_VERTEX.
    416     *
    417     * \sa SYSTEM_VALUE_VERTEX_ID_ZERO_BASE, SYSTEM_VALUE_BASE_VERTEX
    418     */
    419    SYSTEM_VALUE_VERTEX_ID,
    420 
    421    /**
    422     * Instanced ID as supplied to gl_InstanceID
    423     *
    424     * Values assigned to gl_InstanceID always begin with zero, regardless of
    425     * the value of baseinstance.
    426     *
    427     * Section 11.1.3.9 (Shader Inputs) of the OpenGL 4.4 core profile spec
    428     * says:
    429     *
    430     *     "gl_InstanceID holds the integer instance number of the current
    431     *     primitive in an instanced draw call (see section 10.5)."
    432     *
    433     * Through a big chain of pseudocode, section 10.5 describes that
    434     * baseinstance is not counted by gl_InstanceID.  In that section, notice
    435     *
    436     *     "If an enabled vertex attribute array is instanced (it has a
    437     *     non-zero divisor as specified by VertexAttribDivisor), the element
    438     *     index that is transferred to the GL, for all vertices, is given by
    439     *
    440     *         floor(instance/divisor) + baseinstance
    441     *
    442     *     If an array corresponding to an attribute required by a vertex
    443     *     shader is not enabled, then the corresponding element is taken from
    444     *     the current attribute state (see section 10.2)."
    445     *
    446     * Note that baseinstance is \b not included in the value of instance.
    447     */
    448    SYSTEM_VALUE_INSTANCE_ID,
    449 
    450    /**
    451     * Vulkan InstanceIndex.
    452     *
    453     * InstanceIndex = gl_InstanceID + gl_BaseInstance
    454     */
    455    SYSTEM_VALUE_INSTANCE_INDEX,
    456 
    457    /**
    458     * DirectX-style vertex ID.
    459     *
    460     * Unlike \c SYSTEM_VALUE_VERTEX_ID, this system value does \b not include
    461     * the value of basevertex.
    462     *
    463     * \sa SYSTEM_VALUE_VERTEX_ID, SYSTEM_VALUE_BASE_VERTEX
    464     */
    465    SYSTEM_VALUE_VERTEX_ID_ZERO_BASE,
    466 
    467    /**
    468     * Value of \c basevertex passed to \c glDrawElementsBaseVertex and similar
    469     * functions.
    470     *
    471     * \sa SYSTEM_VALUE_VERTEX_ID, SYSTEM_VALUE_VERTEX_ID_ZERO_BASE
    472     */
    473    SYSTEM_VALUE_BASE_VERTEX,
    474 
    475    /**
    476     * Value of \c baseinstance passed to instanced draw entry points
    477     *
    478     * \sa SYSTEM_VALUE_INSTANCE_ID
    479     */
    480    SYSTEM_VALUE_BASE_INSTANCE,
    481 
    482    /**
    483     * From _ARB_shader_draw_parameters:
    484     *
    485     *   "Additionally, this extension adds a further built-in variable,
    486     *    gl_DrawID to the shading language. This variable contains the index
    487     *    of the draw currently being processed by a Multi* variant of a
    488     *    drawing command (such as MultiDrawElements or
    489     *    MultiDrawArraysIndirect)."
    490     *
    491     * If GL_ARB_multi_draw_indirect is not supported, this is always 0.
    492     */
    493    SYSTEM_VALUE_DRAW_ID,
    494    /*@}*/
    495 
    496    /**
    497     * \name Geometry shader system values
    498     */
    499    /*@{*/
    500    SYSTEM_VALUE_INVOCATION_ID,  /**< (Also in Tessellation Control shader) */
    501    /*@}*/
    502 
    503    /**
    504     * \name Fragment shader system values
    505     */
    506    /*@{*/
    507    SYSTEM_VALUE_FRAG_COORD,
    508    SYSTEM_VALUE_FRONT_FACE,
    509    SYSTEM_VALUE_SAMPLE_ID,
    510    SYSTEM_VALUE_SAMPLE_POS,
    511    SYSTEM_VALUE_SAMPLE_MASK_IN,
    512    SYSTEM_VALUE_HELPER_INVOCATION,
    513    /*@}*/
    514 
    515    /**
    516     * \name Tessellation Evaluation shader system values
    517     */
    518    /*@{*/
    519    SYSTEM_VALUE_TESS_COORD,
    520    SYSTEM_VALUE_VERTICES_IN,    /**< Tessellation vertices in input patch */
    521    SYSTEM_VALUE_PRIMITIVE_ID,
    522    SYSTEM_VALUE_TESS_LEVEL_OUTER, /**< TES input */
    523    SYSTEM_VALUE_TESS_LEVEL_INNER, /**< TES input */
    524    /*@}*/
    525 
    526    /**
    527     * \name Compute shader system values
    528     */
    529    /*@{*/
    530    SYSTEM_VALUE_LOCAL_INVOCATION_ID,
    531    SYSTEM_VALUE_LOCAL_INVOCATION_INDEX,
    532    SYSTEM_VALUE_GLOBAL_INVOCATION_ID,
    533    SYSTEM_VALUE_WORK_GROUP_ID,
    534    SYSTEM_VALUE_NUM_WORK_GROUPS,
    535    SYSTEM_VALUE_LOCAL_GROUP_SIZE,
    536    /*@}*/
    537 
    538    /** Required for VK_KHX_multiview */
    539    SYSTEM_VALUE_VIEW_INDEX,
    540 
    541    /**
    542     * Driver internal vertex-count, used (for example) for drivers to
    543     * calculate stride for stream-out outputs.  Not externally visible.
    544     */
    545    SYSTEM_VALUE_VERTEX_CNT,
    546 
    547    SYSTEM_VALUE_MAX             /**< Number of values */
    548 } gl_system_value;
    549 
    550 const char *gl_system_value_name(gl_system_value sysval);
    551 
    552 /**
    553  * The possible interpolation qualifiers that can be applied to a fragment
    554  * shader input in GLSL.
    555  *
    556  * Note: INTERP_MODE_NONE must be 0 so that memsetting the
    557  * ir_variable data structure to 0 causes the default behavior.
    558  */
    559 enum glsl_interp_mode
    560 {
    561    INTERP_MODE_NONE = 0,
    562    INTERP_MODE_SMOOTH,
    563    INTERP_MODE_FLAT,
    564    INTERP_MODE_NOPERSPECTIVE,
    565    INTERP_MODE_COUNT /**< Number of interpolation qualifiers */
    566 };
    567 
    568 enum glsl_interface_packing {
    569    GLSL_INTERFACE_PACKING_STD140,
    570    GLSL_INTERFACE_PACKING_SHARED,
    571    GLSL_INTERFACE_PACKING_PACKED,
    572    GLSL_INTERFACE_PACKING_STD430
    573 };
    574 
    575 const char *glsl_interp_mode_name(enum glsl_interp_mode qual);
    576 
    577 /**
    578  * Fragment program results
    579  */
    580 typedef enum
    581 {
    582    FRAG_RESULT_DEPTH = 0,
    583    FRAG_RESULT_STENCIL = 1,
    584    /* If a single color should be written to all render targets, this
    585     * register is written.  No FRAG_RESULT_DATAn will be written.
    586     */
    587    FRAG_RESULT_COLOR = 2,
    588    FRAG_RESULT_SAMPLE_MASK = 3,
    589 
    590    /* FRAG_RESULT_DATAn are the per-render-target (GLSL gl_FragData[n]
    591     * or ARB_fragment_program fragment.color[n]) color results.  If
    592     * any are written, FRAG_RESULT_COLOR will not be written.
    593     * FRAG_RESULT_DATA1 and up are simply for the benefit of
    594     * gl_frag_result_name() and not to be construed as an upper bound
    595     */
    596    FRAG_RESULT_DATA0 = 4,
    597    FRAG_RESULT_DATA1,
    598    FRAG_RESULT_DATA2,
    599    FRAG_RESULT_DATA3,
    600    FRAG_RESULT_DATA4,
    601    FRAG_RESULT_DATA5,
    602    FRAG_RESULT_DATA6,
    603    FRAG_RESULT_DATA7,
    604 } gl_frag_result;
    605 
    606 const char *gl_frag_result_name(gl_frag_result result);
    607 
    608 #define FRAG_RESULT_MAX		(FRAG_RESULT_DATA0 + MAX_DRAW_BUFFERS)
    609 
    610 /**
    611  * \brief Layout qualifiers for gl_FragDepth.
    612  *
    613  * Extension AMD_conservative_depth allows gl_FragDepth to be redeclared with
    614  * a layout qualifier.
    615  *
    616  * \see enum ir_depth_layout
    617  */
    618 enum gl_frag_depth_layout
    619 {
    620    FRAG_DEPTH_LAYOUT_NONE, /**< No layout is specified. */
    621    FRAG_DEPTH_LAYOUT_ANY,
    622    FRAG_DEPTH_LAYOUT_GREATER,
    623    FRAG_DEPTH_LAYOUT_LESS,
    624    FRAG_DEPTH_LAYOUT_UNCHANGED
    625 };
    626 
    627 /**
    628  * \brief Buffer access qualifiers
    629  */
    630 enum gl_buffer_access_qualifier
    631 {
    632    ACCESS_COHERENT = 1,
    633    ACCESS_RESTRICT = 2,
    634    ACCESS_VOLATILE = 4,
    635 };
    636 
    637 /**
    638  * \brief Blend support qualifiers
    639  */
    640 enum gl_advanced_blend_mode
    641 {
    642    BLEND_NONE           = 0x0000,
    643 
    644    BLEND_MULTIPLY       = 0x0001,
    645    BLEND_SCREEN         = 0x0002,
    646    BLEND_OVERLAY        = 0x0004,
    647    BLEND_DARKEN         = 0x0008,
    648    BLEND_LIGHTEN        = 0x0010,
    649    BLEND_COLORDODGE     = 0x0020,
    650    BLEND_COLORBURN      = 0x0040,
    651    BLEND_HARDLIGHT      = 0x0080,
    652    BLEND_SOFTLIGHT      = 0x0100,
    653    BLEND_DIFFERENCE     = 0x0200,
    654    BLEND_EXCLUSION      = 0x0400,
    655    BLEND_HSL_HUE        = 0x0800,
    656    BLEND_HSL_SATURATION = 0x1000,
    657    BLEND_HSL_COLOR      = 0x2000,
    658    BLEND_HSL_LUMINOSITY = 0x4000,
    659 
    660    BLEND_ALL            = 0x7fff,
    661 };
    662 
    663 enum gl_tess_spacing
    664 {
    665    TESS_SPACING_UNSPECIFIED,
    666    TESS_SPACING_EQUAL,
    667    TESS_SPACING_FRACTIONAL_ODD,
    668    TESS_SPACING_FRACTIONAL_EVEN,
    669 };
    670 
    671 /**
    672  * A compare function enum for use in compiler lowering passes.  This is in
    673  * the same order as GL's compare functions (shifted down by GL_NEVER), and is
    674  * exactly the same as gallium's PIPE_FUNC_*.
    675  */
    676 enum compare_func
    677 {
    678    COMPARE_FUNC_NEVER,
    679    COMPARE_FUNC_LESS,
    680    COMPARE_FUNC_EQUAL,
    681    COMPARE_FUNC_LEQUAL,
    682    COMPARE_FUNC_GREATER,
    683    COMPARE_FUNC_NOTEQUAL,
    684    COMPARE_FUNC_GEQUAL,
    685    COMPARE_FUNC_ALWAYS,
    686 };
    687 
    688 #ifdef __cplusplus
    689 } /* extern "C" */
    690 #endif
    691 
    692 #endif /* SHADER_ENUMS_H */
    693