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 #pragma once
  25 #ifndef GLSL_LINK_VARYINGS_H
  26 #define GLSL_LINK_VARYINGS_H
  27
  28 /**
  29  * \file link_varyings.h
  30  *
  31  * Linker functions related specifically to linking varyings between shader
  32  * stages.
  33  */
  34
  35
  36 #include "main/glheader.h"
  37
  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               const unsigned max_outputs) const;
 102    const tfeedback_candidate *find_candidate(gl_shader_program *prog,
 103                                              hash_table *tfeedback_candidates);
 104
 105    bool is_next_buffer_separator() const
 106    {
 107       return this->next_buffer_separator;
 108    }
 109
 110    bool is_varying() const
 111    {
 112       return !this->next_buffer_separator && !this->skip_components;
 113    }
 114
 115    const char *name() const
 116    {
 117       return this->orig_name;
 118    }
 119
 120    unsigned get_stream_id() const
 121    {
 122       return this->stream_id;
 123    }
 124
 125    unsigned get_buffer() const
 126    {
 127       return this->buffer;
 128    }
 129
 130    unsigned get_offset() const
 131    {
 132       return this->offset;
 133    }
 134
 135    /**
 136     * The total number of varying components taken up by this variable.  Only
 137     * valid if assign_location() has been called.
 138     */
 139    unsigned num_components() const
 140    {
 141       if (this->lowered_builtin_array_variable)
 142          return this->size;
 143       else
 144          return this->vector_elements * this->matrix_columns * this->size *
 145             (this->is_double() ? 2 : 1);
 146    }
 147
 148    unsigned get_location() const {
 149       return this->location;
 150    }
 151
 152 private:
 153
 154    bool is_double() const
 155    {
 156       switch (this->type) {
 157       case GL_DOUBLE:
 158       case GL_DOUBLE_VEC2:
 159       case GL_DOUBLE_VEC3:
 160       case GL_DOUBLE_VEC4:
 161       case GL_DOUBLE_MAT2:
 162       case GL_DOUBLE_MAT2x3:
 163       case GL_DOUBLE_MAT2x4:
 164       case GL_DOUBLE_MAT3:
 165       case GL_DOUBLE_MAT3x2:
 166       case GL_DOUBLE_MAT3x4:
 167       case GL_DOUBLE_MAT4:
 168       case GL_DOUBLE_MAT4x2:
 169       case GL_DOUBLE_MAT4x3:
 170          return true;
 171       default:
 172          return false;
 173       }
 174    }
 175
 176    /**
 177     * The name that was supplied to glTransformFeedbackVaryings.  Used for
 178     * error reporting and glGetTransformFeedbackVarying().
 179     */
 180    const char *orig_name;
 181
 182    /**
 183     * The name of the variable, parsed from orig_name.
 184     */
 185    const char *var_name;
 186
 187    /**
 188     * True if the declaration in orig_name represents an array.
 189     */
 190    bool is_subscripted;
 191
 192    /**
 193     * If is_subscripted is true, the subscript that was specified in orig_name.
 194     */
 195    unsigned array_subscript;
 196
 197    /**
 198     * Non-zero if the variable is gl_ClipDistance, glTessLevelOuter or
 199     * gl_TessLevelInner and the driver lowers it to gl_*MESA.
 200     */
 201    enum {
 202       none,
 203       clip_distance,
 204       tess_level_outer,
 205       tess_level_inner,
 206    } lowered_builtin_array_variable;
 207
 208    /**
 209     * The vertex shader output location that the linker assigned for this
 210     * variable.  -1 if a location hasn't been assigned yet.
 211     */
 212    int location;
 213
 214    /**
 215     * Used to store the buffer assigned by xfb_buffer.
 216     */
 217    unsigned buffer;
 218
 219    /**
 220     * Used to store the offset assigned by xfb_offset.
 221     */
 222    unsigned offset;
 223
 224    /**
 225     * If non-zero, then this variable may be packed along with other variables
 226     * into a single varying slot, so this offset should be applied when
 227     * accessing components.  For example, an offset of 1 means that the x
 228     * component of this variable is actually stored in component y of the
 229     * location specified by \c location.
 230     *
 231     * Only valid if location != -1.
 232     */
 233    unsigned location_frac;
 234
 235    /**
 236     * If location != -1, the number of vector elements in this variable, or 1
 237     * if this variable is a scalar.
 238     */
 239    unsigned vector_elements;
 240
 241    /**
 242     * If location != -1, the number of matrix columns in this variable, or 1
 243     * if this variable is not a matrix.
 244     */
 245    unsigned matrix_columns;
 246
 247    /** Type of the varying returned by glGetTransformFeedbackVarying() */
 248    GLenum type;
 249
 250    /**
 251     * If location != -1, the size that should be returned by
 252     * glGetTransformFeedbackVarying().
 253     */
 254    unsigned size;
 255
 256    /**
 257     * How many components to skip. If non-zero, this is
 258     * gl_SkipComponents{1,2,3,4} from ARB_transform_feedback3.
 259     */
 260    unsigned skip_components;
 261
 262    /**
 263     * Whether this is gl_NextBuffer from ARB_transform_feedback3.
 264     */
 265    bool next_buffer_separator;
 266
 267    /**
 268     * If find_candidate() has been called, pointer to the tfeedback_candidate
 269     * data structure that was found.  Otherwise NULL.
 270     */
 271    const tfeedback_candidate *matched_candidate;
 272
 273    /**
 274     * StreamId assigned to this varying (defaults to 0). Can only be set to
 275     * values other than 0 in geometry shaders that use the stream layout
 276     * modifier. Accepted values must be in the range [0, MAX_VERTEX_STREAMS-1].
 277     */
 278    unsigned stream_id;
 279 };
 280
 281
 282 void
 283 cross_validate_outputs_to_inputs(struct gl_shader_program *prog,
 284                                  gl_shader *producer, gl_shader *consumer);
 285
 286 bool
 287 parse_tfeedback_decls(struct gl_context *ctx, struct gl_shader_program *prog,
 288                       const void *mem_ctx, unsigned num_names,
 289                       char **varying_names, tfeedback_decl *decls);
 290
 291 bool
 292 process_xfb_layout_qualifiers(void *mem_ctx, const gl_shader *sh,
 293                               unsigned *num_tfeedback_decls,
 294                               char ***varying_names);
 295
 296 void
 297 remove_unused_shader_inputs_and_outputs(bool is_separate_shader_object,
 298                                         gl_shader *sh,
 299                                         enum ir_variable_mode mode);
 300
 301 bool
 302 store_tfeedback_info(struct gl_context *ctx, struct gl_shader_program *prog,
 303                      unsigned num_tfeedback_decls,
 304                      tfeedback_decl *tfeedback_decls);
 305
 306 bool
 307 assign_varying_locations(struct gl_context *ctx,
 308                          void *mem_ctx,
 309                          struct gl_shader_program *prog,
 310                          gl_shader *producer, gl_shader *consumer,
 311                          unsigned num_tfeedback_decls,
 312                          tfeedback_decl *tfeedback_decls);
 313
 314 bool
 315 check_against_output_limit(struct gl_context *ctx,
 316                            struct gl_shader_program *prog,
 317                            gl_shader *producer);
 318
 319 bool
 320 check_against_input_limit(struct gl_context *ctx,
 321                           struct gl_shader_program *prog,
 322                           gl_shader *consumer);
 323
 324 #endif /* GLSL_LINK_VARYINGS_H */