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/*

 * Copyright © 2012 Intel Corporation

 *

 * Permission is hereby granted, free of charge, to any person obtaining a

 * copy of this software and associated documentation files (the "Software"),

 * to deal in the Software without restriction, including without limitation

 * the rights to use, copy, modify, merge, publish, distribute, sublicense,

 * and/or sell copies of the Software, and to permit persons to whom the

 * Software is furnished to do so, subject to the following conditions:

 *

 * The above copyright notice and this permission notice (including the next

 * paragraph) shall be included in all copies or substantial portions of the

 * Software.

 *

 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR

 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,

 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL

 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER

 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING

 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER

 * DEALINGS IN THE SOFTWARE.

 */

#pragma once

#ifndef GLSL_LINK_VARYINGS_H

#define GLSL_LINK_VARYINGS_H

/**

 * \file link_varyings.h

 *

 * Linker functions related specifically to linking varyings between shader

 * stages.

 */

#include "main/glheader.h"

struct gl_shader_program;

struct gl_shader;

class ir_variable;

/**

 * Data structure describing a varying which is available for use in transform

 * feedback.

 *

 * For example, if the vertex shader contains:

 *

 *     struct S {

 *       vec4 foo;

 *       float[3] bar;

 *     };

 *

 *     varying S[2] v;

 *

 * Then there would be tfeedback_candidate objects corresponding to the

 * following varyings:

 *

 *     v[0].foo

 *     v[0].bar

 *     v[1].foo

 *     v[1].bar

 */

struct tfeedback_candidate

{

   /**

    * Toplevel variable containing this varying.  In the above example, this

    * would point to the declaration of the varying v.

    */

   ir_variable *toplevel_var;

   /**

    * Type of this varying.  In the above example, this would point to the

    * glsl_type for "vec4" or "float[3]".

    */

   const glsl_type *type;

   /**

    * Offset within the toplevel variable where this varying occurs (counted

    * in multiples of the size of a float).

    */

   unsigned offset;

};

/**

 * Data structure tracking information about a transform feedback declaration

 * during linking.

 */

class tfeedback_decl

{

public:

   void init(struct gl_context *ctx, struct gl_shader_program *prog,

             const void *mem_ctx, const char *input);

   static bool is_same(const tfeedback_decl &x, const tfeedback_decl &y);

   bool assign_location(struct gl_context *ctx,

                        struct gl_shader_program *prog);

   unsigned get_num_outputs() const;

   bool store(struct gl_context *ctx, struct gl_shader_program *prog,

              struct gl_transform_feedback_info *info, unsigned buffer,

              const unsigned max_outputs) const;

   const tfeedback_candidate *find_candidate(gl_shader_program *prog,

                                             hash_table *tfeedback_candidates);

   bool is_next_buffer_separator() const

   {

      return this->next_buffer_separator;

   }

   bool is_varying() const

   {

      return !this->next_buffer_separator && !this->skip_components;

   }

   /**

    * The total number of varying components taken up by this variable.  Only

    * valid if assign_location() has been called.

    */

   unsigned num_components() const

   {

      if (this->is_clip_distance_mesa)

         return this->size;

      else

         return this->vector_elements * this->matrix_columns * this->size;

   }

   unsigned get_location() const {

      return this->location;

   }

private:

   /**

    * The name that was supplied to glTransformFeedbackVaryings.  Used for

    * error reporting and glGetTransformFeedbackVarying().

    */

   const char *orig_name;

   /**

    * The name of the variable, parsed from orig_name.

    */

   const char *var_name;

   /**

    * True if the declaration in orig_name represents an array.

    */

   bool is_subscripted;

   /**

    * If is_subscripted is true, the subscript that was specified in orig_name.

    */

   unsigned array_subscript;

   /**

    * True if the variable is gl_ClipDistance and the driver lowers

    * gl_ClipDistance to gl_ClipDistanceMESA.

    */

   bool is_clip_distance_mesa;

   /**

    * The vertex shader output location that the linker assigned for this

    * variable.  -1 if a location hasn't been assigned yet.

    */

   int location;

   /**

    * If non-zero, then this variable may be packed along with other variables

    * into a single varying slot, so this offset should be applied when

    * accessing components.  For example, an offset of 1 means that the x

    * component of this variable is actually stored in component y of the

    * location specified by \c location.

    *

    * Only valid if location != -1.

    */

   unsigned location_frac;

   /**

    * If location != -1, the number of vector elements in this variable, or 1

    * if this variable is a scalar.

    */

   unsigned vector_elements;

   /**

    * If location != -1, the number of matrix columns in this variable, or 1

    * if this variable is not a matrix.

    */

   unsigned matrix_columns;

   /** Type of the varying returned by glGetTransformFeedbackVarying() */

   GLenum type;

   /**

    * If location != -1, the size that should be returned by

    * glGetTransformFeedbackVarying().

    */

   unsigned size;

   /**

    * How many components to skip. If non-zero, this is

    * gl_SkipComponents{1,2,3,4} from ARB_transform_feedback3.

    */

   unsigned skip_components;

   /**

    * Whether this is gl_NextBuffer from ARB_transform_feedback3.

    */

   bool next_buffer_separator;

   /**

    * If find_candidate() has been called, pointer to the tfeedback_candidate

    * data structure that was found.  Otherwise NULL.

    */

   const tfeedback_candidate *matched_candidate;

};

bool

cross_validate_outputs_to_inputs(struct gl_shader_program *prog,

				 gl_shader *producer, gl_shader *consumer);

bool

parse_tfeedback_decls(struct gl_context *ctx, struct gl_shader_program *prog,

                      const void *mem_ctx, unsigned num_names,

                      char **varying_names, tfeedback_decl *decls);

bool

store_tfeedback_info(struct gl_context *ctx, struct gl_shader_program *prog,

                     unsigned num_tfeedback_decls,

                     tfeedback_decl *tfeedback_decls);

bool

assign_varying_locations(struct gl_context *ctx,

			 void *mem_ctx,

			 struct gl_shader_program *prog,

			 gl_shader *producer, gl_shader *consumer,

                         unsigned num_tfeedback_decls,

                         tfeedback_decl *tfeedback_decls);

bool

check_against_varying_limit(struct gl_context *ctx,

                            struct gl_shader_program *prog,

                            gl_shader *consumer);

#endif /* GLSL_LINK_VARYINGS_H */