src/compiler/glsl/link_varyings.h - platform/external/mesa3d - Git at Google

 /*
  * 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.
  */

 #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"
 #include "program/prog_parameter.h"
 #include "util/bitset.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, 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,
               unsigned buffer_index, const unsigned max_outputs,
               BITSET_WORD *used_components[MAX_FEEDBACK_BUFFERS],
               bool *explicit_stride, bool has_xfb_qualifiers,
               const void *mem_ctx) const;
    const tfeedback_candidate *find_candidate(gl_shader_program *prog,
                                              hash_table *tfeedback_candidates);
    void set_lowered_candidate(const tfeedback_candidate *candidate);

    bool is_next_buffer_separator() const
    {
       return this->next_buffer_separator;
    }

    bool is_varying_written() const
    {
       if (this->next_buffer_separator || this->skip_components)
          return false;

       return this->matched_candidate->toplevel_var->data.assigned;
    }

    bool is_varying() const
    {
       return !this->next_buffer_separator && !this->skip_components;
    }

    bool is_aligned(unsigned dmul, unsigned offset) const
    {
       return (dmul * (this->array_subscript + offset)) % 4 == 0;
    }

    const char *name() const
    {
       return this->orig_name;
    }

    unsigned get_stream_id() const
    {
       return this->stream_id;
    }

    unsigned get_buffer() const
    {
       return this->buffer;
    }

    unsigned get_offset() const
    {
       return this->offset;
    }

    /**
     * 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->lowered_builtin_array_variable)
          return this->size;
       else
          return this->vector_elements * this->matrix_columns * this->size *
             (this->is_64bit() ? 2 : 1);
    }

    unsigned get_location() const {
       return this->location;
    }

 private:

    bool is_64bit() const
    {
       return _mesa_gl_datatype_is_64bit(this->type);
    }

    /**
     * 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;

    /**
     * Non-zero if the variable is gl_ClipDistance, glTessLevelOuter or
     * gl_TessLevelInner and the driver lowers it to gl_*MESA.
     */
    enum {
       none,
       clip_distance,
       cull_distance,
       tess_level_outer,
       tess_level_inner,
    } lowered_builtin_array_variable;

    /**
     * The vertex shader output location that the linker assigned for this
     * variable.  -1 if a location hasn't been assigned yet.
     */
    int location;

    /**
     * Used to store the buffer assigned by xfb_buffer.
     */
    unsigned buffer;

    /**
     * Used to store the offset assigned by xfb_offset.
     */
    unsigned offset;

    /**
     * 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;

    /**
     * StreamId assigned to this varying (defaults to 0). Can only be set to
     * values other than 0 in geometry shaders that use the stream layout
     * modifier. Accepted values must be in the range [0, MAX_VERTEX_STREAMS-1].
     */
    unsigned stream_id;
 };

 bool
 link_varyings(struct gl_shader_program *prog, unsigned first, unsigned last,
               struct gl_context *ctx, void *mem_ctx);

 void
 validate_first_and_last_interface_explicit_locations(struct gl_context *ctx,
                                                      struct gl_shader_program *prog,
                                                      gl_shader_stage first,
                                                      gl_shader_stage last);

 void
 cross_validate_outputs_to_inputs(struct gl_context *ctx,
                                  struct gl_shader_program *prog,
                                  gl_linked_shader *producer,
                                  gl_linked_shader *consumer);

 #endif /* GLSL_LINK_VARYINGS_H */
	/*
	* 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.
	*/

	#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"
	#include "program/prog_parameter.h"
	#include "util/bitset.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, 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,
	unsigned buffer_index, const unsigned max_outputs,
	BITSET_WORD *used_components[MAX_FEEDBACK_BUFFERS],
	bool *explicit_stride, bool has_xfb_qualifiers,
	const void *mem_ctx) const;
	const tfeedback_candidate find_candidate(gl_shader_program prog,
	hash_table *tfeedback_candidates);
	void set_lowered_candidate(const tfeedback_candidate *candidate);

	bool is_next_buffer_separator() const
	{
	return this->next_buffer_separator;
	}

	bool is_varying_written() const
	{
	if (this->next_buffer_separator \|\| this->skip_components)
	return false;

	return this->matched_candidate->toplevel_var->data.assigned;
	}

	bool is_varying() const
	{
	return !this->next_buffer_separator && !this->skip_components;
	}

	bool is_aligned(unsigned dmul, unsigned offset) const
	{
	return (dmul * (this->array_subscript + offset)) % 4 == 0;
	}

	const char *name() const
	{
	return this->orig_name;
	}

	unsigned get_stream_id() const
	{
	return this->stream_id;
	}

	unsigned get_buffer() const
	{
	return this->buffer;
	}

	unsigned get_offset() const
	{
	return this->offset;
	}

	/**
	* 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->lowered_builtin_array_variable)
	return this->size;
	else
	return this->vector_elements * this->matrix_columns * this->size *
	(this->is_64bit() ? 2 : 1);
	}

	unsigned get_location() const {
	return this->location;
	}

	private:

	bool is_64bit() const
	{
	return _mesa_gl_datatype_is_64bit(this->type);
	}

	/**
	* 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;

	/**
	* Non-zero if the variable is gl_ClipDistance, glTessLevelOuter or
	* gl_TessLevelInner and the driver lowers it to gl_*MESA.
	*/
	enum {
	none,
	clip_distance,
	cull_distance,
	tess_level_outer,
	tess_level_inner,
	} lowered_builtin_array_variable;

	/**
	* The vertex shader output location that the linker assigned for this
	* variable. -1 if a location hasn't been assigned yet.
	*/
	int location;

	/**
	* Used to store the buffer assigned by xfb_buffer.
	*/
	unsigned buffer;

	/**
	* Used to store the offset assigned by xfb_offset.
	*/
	unsigned offset;

	/**
	* 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;

	/**
	* StreamId assigned to this varying (defaults to 0). Can only be set to
	* values other than 0 in geometry shaders that use the stream layout
	* modifier. Accepted values must be in the range [0, MAX_VERTEX_STREAMS-1].
	*/
	unsigned stream_id;
	};

	bool
	link_varyings(struct gl_shader_program *prog, unsigned first, unsigned last,
	struct gl_context ctx, void mem_ctx);

	void
	validate_first_and_last_interface_explicit_locations(struct gl_context *ctx,
	struct gl_shader_program *prog,
	gl_shader_stage first,
	gl_shader_stage last);

	void
	cross_validate_outputs_to_inputs(struct gl_context *ctx,
	struct gl_shader_program *prog,
	gl_linked_shader *producer,
	gl_linked_shader *consumer);

	#endif /* GLSL_LINK_VARYINGS_H */