src/compiler/glsl/link_varyings.h

   1 /*
   2  * Copyright © 2012 Intel Corporation
   3  *
   4  * Permission is hereby granted, free of charge, to any person obtaining a
   5  * copy of this software and associated documentation files (the "Software"),
   6  * to deal in the Software without restriction, including without limitation
   7  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
   8  * and/or sell copies of the Software, and to permit persons to whom the
   9  * Software is furnished to do so, subject to the following conditions:
  10  *
  11  * The above copyright notice and this permission notice (including the next
  12  * paragraph) shall be included in all copies or substantial portions of the
  13  * Software.
  14  *
  15  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  16  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  18  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  19  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  20  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
  21  * DEALINGS IN THE SOFTWARE.
  22  */
  23
  24 #ifndef GLSL_LINK_VARYINGS_H
  25 #define GLSL_LINK_VARYINGS_H
  26
  27 /**
  28  * \file link_varyings.h
  29  *
  30  * Linker functions related specifically to linking varyings between shader
  31  * stages.
  32  */
  33
  34
  35 #include "main/glheader.h"
  36 #include "program/prog_parameter.h"
  37 #include "util/bitset.h"
  38
  39 struct gl_shader_program;
  40 struct gl_shader;
  41 class ir_variable;
  42
  43
  44 /**
  45  * Data structure describing a varying which is available for use in transform
  46  * feedback.
  47  *
  48  * For example, if the vertex shader contains:
  49  *
  50  *     struct S {
  51  *       vec4 foo;
  52  *       float[3] bar;
  53  *     };
  54  *
  55  *     varying S[2] v;
  56  *
  57  * Then there would be tfeedback_candidate objects corresponding to the
  58  * following varyings:
  59  *
  60  *     v[0].foo
  61  *     v[0].bar
  62  *     v[1].foo
  63  *     v[1].bar
  64  */
  65 struct tfeedback_candidate
  66 {
  67    /**
  68     * Toplevel variable containing this varying.  In the above example, this
  69     * would point to the declaration of the varying v.
  70     */
  71    ir_variable *toplevel_var;
  72
  73    /**
  74     * Type of this varying.  In the above example, this would point to the
  75     * glsl_type for "vec4" or "float[3]".
  76     */
  77    const glsl_type *type;
  78
  79    /**
  80     * Offset within the toplevel variable where this varying occurs (counted
  81     * in multiples of the size of a float).
  82     */
  83    unsigned offset;
  84 };
  85
  86
  87 /**
  88  * Data structure tracking information about a transform feedback declaration
  89  * during linking.
  90  */
  91 class tfeedback_decl
  92 {
  93 public:
  94    void init(struct gl_context *ctx, const void *mem_ctx, const char *input);
  95    static bool is_same(const tfeedback_decl &x, const tfeedback_decl &y);
  96    bool assign_location(struct gl_context *ctx,
  97                         struct gl_shader_program *prog);
  98    unsigned get_num_outputs() const;
  99    bool store(struct gl_context *ctx, struct gl_shader_program *prog,
 100               struct gl_transform_feedback_info *info, unsigned buffer,
 101               unsigned buffer_index, const unsigned max_outputs,
 102               BITSET_WORD *used_components[MAX_FEEDBACK_BUFFERS],
 103               bool *explicit_stride, bool has_xfb_qualifiers,
 104               const void *mem_ctx) const;
 105    const tfeedback_candidate *find_candidate(gl_shader_program *prog,
 106                                              hash_table *tfeedback_candidates);
 107
 108    bool is_next_buffer_separator() const
 109    {
 110       return this->next_buffer_separator;
 111    }
 112
 113    bool is_varying_written() const
 114    {
 115       if (this->next_buffer_separator || this->skip_components)
 116          return false;
 117
 118       return this->matched_candidate->toplevel_var->data.assigned;
 119    }
 120
 121    bool is_varying() const
 122    {
 123       return !this->next_buffer_separator && !this->skip_components;
 124    }
 125
 126    const char *name() const
 127    {
 128       return this->orig_name;
 129    }
 130
 131    unsigned get_stream_id() const
 132    {
 133       return this->stream_id;
 134    }
 135
 136    unsigned get_buffer() const
 137    {
 138       return this->buffer;
 139    }
 140
 141    unsigned get_offset() const
 142    {
 143       return this->offset;
 144    }
 145
 146    /**
 147     * The total number of varying components taken up by this variable.  Only
 148     * valid if assign_location() has been called.
 149     */
 150    unsigned num_components() const
 151    {
 152       if (this->lowered_builtin_array_variable)
 153          return this->size;
 154       else
 155          return this->vector_elements * this->matrix_columns * this->size *
 156             (this->is_64bit() ? 2 : 1);
 157    }
 158
 159    unsigned get_location() const {
 160       return this->location;
 161    }
 162
 163 private:
 164
 165    bool is_64bit() const
 166    {
 167       return _mesa_gl_datatype_is_64bit(this->type);
 168    }
 169
 170    /**
 171     * The name that was supplied to glTransformFeedbackVaryings.  Used for
 172     * error reporting and glGetTransformFeedbackVarying().
 173     */
 174    const char *orig_name;
 175
 176    /**
 177     * The name of the variable, parsed from orig_name.
 178     */
 179    const char *var_name;
 180
 181    /**
 182     * True if the declaration in orig_name represents an array.
 183     */
 184    bool is_subscripted;
 185
 186    /**
 187     * If is_subscripted is true, the subscript that was specified in orig_name.
 188     */
 189    unsigned array_subscript;
 190
 191    /**
 192     * Non-zero if the variable is gl_ClipDistance, glTessLevelOuter or
 193     * gl_TessLevelInner and the driver lowers it to gl_*MESA.
 194     */
 195    enum {
 196       none,
 197       clip_distance,
 198       cull_distance,
 199       tess_level_outer,
 200       tess_level_inner,
 201    } lowered_builtin_array_variable;
 202
 203    /**
 204     * The vertex shader output location that the linker assigned for this
 205     * variable.  -1 if a location hasn't been assigned yet.
 206     */
 207    int location;
 208
 209    /**
 210     * Used to store the buffer assigned by xfb_buffer.
 211     */
 212    unsigned buffer;
 213
 214    /**
 215     * Used to store the offset assigned by xfb_offset.
 216     */
 217    unsigned offset;
 218
 219    /**
 220     * If non-zero, then this variable may be packed along with other variables
 221     * into a single varying slot, so this offset should be applied when
 222     * accessing components.  For example, an offset of 1 means that the x
 223     * component of this variable is actually stored in component y of the
 224     * location specified by \c location.
 225     *
 226     * Only valid if location != -1.
 227     */
 228    unsigned location_frac;
 229
 230    /**
 231     * If location != -1, the number of vector elements in this variable, or 1
 232     * if this variable is a scalar.
 233     */
 234    unsigned vector_elements;
 235
 236    /**
 237     * If location != -1, the number of matrix columns in this variable, or 1
 238     * if this variable is not a matrix.
 239     */
 240    unsigned matrix_columns;
 241
 242    /** Type of the varying returned by glGetTransformFeedbackVarying() */
 243    GLenum type;
 244
 245    /**
 246     * If location != -1, the size that should be returned by
 247     * glGetTransformFeedbackVarying().
 248     */
 249    unsigned size;
 250
 251    /**
 252     * How many components to skip. If non-zero, this is
 253     * gl_SkipComponents{1,2,3,4} from ARB_transform_feedback3.
 254     */
 255    unsigned skip_components;
 256
 257    /**
 258     * Whether this is gl_NextBuffer from ARB_transform_feedback3.
 259     */
 260    bool next_buffer_separator;
 261
 262    /**
 263     * If find_candidate() has been called, pointer to the tfeedback_candidate
 264     * data structure that was found.  Otherwise NULL.
 265     */
 266    const tfeedback_candidate *matched_candidate;
 267
 268    /**
 269     * StreamId assigned to this varying (defaults to 0). Can only be set to
 270     * values other than 0 in geometry shaders that use the stream layout
 271     * modifier. Accepted values must be in the range [0, MAX_VERTEX_STREAMS-1].
 272     */
 273    unsigned stream_id;
 274 };
 275
 276 bool
 277 link_varyings(struct gl_shader_program *prog, unsigned first, unsigned last,
 278               struct gl_context *ctx, void *mem_ctx);
 279
 280 void
 281 validate_first_and_last_interface_explicit_locations(struct gl_context *ctx,
 282                                                      struct gl_shader_program *prog,
 283                                                      gl_shader_stage first,
 284                                                      gl_shader_stage last);
 285
 286 void
 287 cross_validate_outputs_to_inputs(struct gl_context *ctx,
 288                                  struct gl_shader_program *prog,
 289                                  gl_linked_shader *producer,
 290                                  gl_linked_shader *consumer);
 291
 292 #endif /* GLSL_LINK_VARYINGS_H */