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
  37
  38 struct gl_shader_program;
  39 struct gl_shader;
  40 class ir_variable;
  41
  42
  43 /**
  44  * Data structure describing a varying which is available for use in transform
  45  * feedback.
  46  *
  47  * For example, if the vertex shader contains:
  48  *
  49  *     struct S {
  50  *       vec4 foo;
  51  *       float[3] bar;
  52  *     };
  53  *
  54  *     varying S[2] v;
  55  *
  56  * Then there would be tfeedback_candidate objects corresponding to the
  57  * following varyings:
  58  *
  59  *     v[0].foo
  60  *     v[0].bar
  61  *     v[1].foo
  62  *     v[1].bar
  63  */
  64 struct tfeedback_candidate
  65 {
  66    /**
  67     * Toplevel variable containing this varying.  In the above example, this
  68     * would point to the declaration of the varying v.
  69     */
  70    ir_variable *toplevel_var;
  71
  72    /**
  73     * Type of this varying.  In the above example, this would point to the
  74     * glsl_type for "vec4" or "float[3]".
  75     */
  76    const glsl_type *type;
  77
  78    /**
  79     * Offset within the toplevel variable where this varying occurs (counted
  80     * in multiples of the size of a float).
  81     */
  82    unsigned offset;
  83 };
  84
  85
  86 /**
  87  * Data structure tracking information about a transform feedback declaration
  88  * during linking.
  89  */
  90 class tfeedback_decl
  91 {
  92 public:
  93    void init(struct gl_context *ctx, const void *mem_ctx, const char *input);
  94    static bool is_same(const tfeedback_decl &x, const tfeedback_decl &y);
  95    bool assign_location(struct gl_context *ctx,
  96                         struct gl_shader_program *prog);
  97    unsigned get_num_outputs() const;
  98    bool store(struct gl_context *ctx, struct gl_shader_program *prog,
  99               struct gl_transform_feedback_info *info, unsigned buffer,
 100               unsigned buffer_index, const unsigned max_outputs,
 101               bool *explicit_stride, bool has_xfb_qualifiers) 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_written() const
 111    {
 112       if (this->next_buffer_separator || this->skip_components)
 113          return false;
 114
 115       return this->matched_candidate->toplevel_var->data.assigned;
 116    }
 117
 118    bool is_varying() const
 119    {
 120       return !this->next_buffer_separator && !this->skip_components;
 121    }
 122
 123    const char *name() const
 124    {
 125       return this->orig_name;
 126    }
 127
 128    unsigned get_stream_id() const
 129    {
 130       return this->stream_id;
 131    }
 132
 133    unsigned get_buffer() const
 134    {
 135       return this->buffer;
 136    }
 137
 138    unsigned get_offset() const
 139    {
 140       return this->offset;
 141    }
 142
 143    /**
 144     * The total number of varying components taken up by this variable.  Only
 145     * valid if assign_location() has been called.
 146     */
 147    unsigned num_components() const
 148    {
 149       if (this->lowered_builtin_array_variable)
 150          return this->size;
 151       else
 152          return this->vector_elements * this->matrix_columns * this->size *
 153             (this->is_64bit() ? 2 : 1);
 154    }
 155
 156    unsigned get_location() const {
 157       return this->location;
 158    }
 159
 160 private:
 161
 162    bool is_64bit() const
 163    {
 164       switch (this->type) {
 165       case GL_DOUBLE:
 166       case GL_DOUBLE_VEC2:
 167       case GL_DOUBLE_VEC3:
 168       case GL_DOUBLE_VEC4:
 169       case GL_DOUBLE_MAT2:
 170       case GL_DOUBLE_MAT2x3:
 171       case GL_DOUBLE_MAT2x4:
 172       case GL_DOUBLE_MAT3:
 173       case GL_DOUBLE_MAT3x2:
 174       case GL_DOUBLE_MAT3x4:
 175       case GL_DOUBLE_MAT4:
 176       case GL_DOUBLE_MAT4x2:
 177       case GL_DOUBLE_MAT4x3:
 178       case GL_INT64_ARB:
 179       case GL_INT64_VEC2_ARB:
 180       case GL_INT64_VEC3_ARB:
 181       case GL_INT64_VEC4_ARB:
 182       case GL_UNSIGNED_INT64_ARB:
 183       case GL_UNSIGNED_INT64_VEC2_ARB:
 184       case GL_UNSIGNED_INT64_VEC3_ARB:
 185       case GL_UNSIGNED_INT64_VEC4_ARB:
 186          return true;
 187       default:
 188          return false;
 189       }
 190    }
 191
 192    /**
 193     * The name that was supplied to glTransformFeedbackVaryings.  Used for
 194     * error reporting and glGetTransformFeedbackVarying().
 195     */
 196    const char *orig_name;
 197
 198    /**
 199     * The name of the variable, parsed from orig_name.
 200     */
 201    const char *var_name;
 202
 203    /**
 204     * True if the declaration in orig_name represents an array.
 205     */
 206    bool is_subscripted;
 207
 208    /**
 209     * If is_subscripted is true, the subscript that was specified in orig_name.
 210     */
 211    unsigned array_subscript;
 212
 213    /**
 214     * Non-zero if the variable is gl_ClipDistance, glTessLevelOuter or
 215     * gl_TessLevelInner and the driver lowers it to gl_*MESA.
 216     */
 217    enum {
 218       none,
 219       clip_distance,
 220       cull_distance,
 221       tess_level_outer,
 222       tess_level_inner,
 223    } lowered_builtin_array_variable;
 224
 225    /**
 226     * The vertex shader output location that the linker assigned for this
 227     * variable.  -1 if a location hasn't been assigned yet.
 228     */
 229    int location;
 230
 231    /**
 232     * Used to store the buffer assigned by xfb_buffer.
 233     */
 234    unsigned buffer;
 235
 236    /**
 237     * Used to store the offset assigned by xfb_offset.
 238     */
 239    unsigned offset;
 240
 241    /**
 242     * If non-zero, then this variable may be packed along with other variables
 243     * into a single varying slot, so this offset should be applied when
 244     * accessing components.  For example, an offset of 1 means that the x
 245     * component of this variable is actually stored in component y of the
 246     * location specified by \c location.
 247     *
 248     * Only valid if location != -1.
 249     */
 250    unsigned location_frac;
 251
 252    /**
 253     * If location != -1, the number of vector elements in this variable, or 1
 254     * if this variable is a scalar.
 255     */
 256    unsigned vector_elements;
 257
 258    /**
 259     * If location != -1, the number of matrix columns in this variable, or 1
 260     * if this variable is not a matrix.
 261     */
 262    unsigned matrix_columns;
 263
 264    /** Type of the varying returned by glGetTransformFeedbackVarying() */
 265    GLenum type;
 266
 267    /**
 268     * If location != -1, the size that should be returned by
 269     * glGetTransformFeedbackVarying().
 270     */
 271    unsigned size;
 272
 273    /**
 274     * How many components to skip. If non-zero, this is
 275     * gl_SkipComponents{1,2,3,4} from ARB_transform_feedback3.
 276     */
 277    unsigned skip_components;
 278
 279    /**
 280     * Whether this is gl_NextBuffer from ARB_transform_feedback3.
 281     */
 282    bool next_buffer_separator;
 283
 284    /**
 285     * If find_candidate() has been called, pointer to the tfeedback_candidate
 286     * data structure that was found.  Otherwise NULL.
 287     */
 288    const tfeedback_candidate *matched_candidate;
 289
 290    /**
 291     * StreamId assigned to this varying (defaults to 0). Can only be set to
 292     * values other than 0 in geometry shaders that use the stream layout
 293     * modifier. Accepted values must be in the range [0, MAX_VERTEX_STREAMS-1].
 294     */
 295    unsigned stream_id;
 296 };
 297
 298 bool
 299 link_varyings(struct gl_shader_program *prog, unsigned first, unsigned last,
 300               struct gl_context *ctx, void *mem_ctx);
 301
 302 void
 303 cross_validate_outputs_to_inputs(struct gl_shader_program *prog,
 304                                  gl_linked_shader *producer,
 305                                  gl_linked_shader *consumer);
 306
 307 #endif /* GLSL_LINK_VARYINGS_H */