src/mesa/vbo/vbo_primitive_restart.c - platform/external/mesa3d - Git at Google

 /*
  * Copyright 2007 VMware, Inc.
  * All Rights Reserved.
  *
  * 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.
  *
  * Authors:
  *    Jordan Justen <jordan.l.justen@intel.com>
  *
  */

 #include "main/imports.h"
 #include "main/bufferobj.h"
 #include "main/macros.h"
 #include "main/varray.h"

 #include "vbo.h"
 #include "vbo_context.h"

 #define UPDATE_MIN2(a, b) (a) = MIN2((a), (b))
 #define UPDATE_MAX2(a, b) (a) = MAX2((a), (b))

 /*
  * Notes on primitive restart:
  * The code below is used when the driver does not fully support primitive
  * restart (for example, if it only does restart index of ~0).
  *
  * We map the index buffer, find the restart indexes, unmap
  * the index buffer then draw the sub-primitives delineated by the restarts.
  *
  * A couple possible optimizations:
  * 1. Save the list of sub-primitive (start, count) values in a list attached
  *    to the index buffer for re-use in subsequent draws.  The list would be
  *    invalidated when the contents of the buffer changed.
  * 2. If drawing triangle strips or quad strips, create a new index buffer
  *    that uses duplicated vertices to render the disjoint strips as one
  *    long strip.  We'd have to be careful to avoid using too much memory
  *    for this.
  *
  * Finally, some apps might perform better if they don't use primitive restart
  * at all rather than this fallback path.  Set MESA_EXTENSION_OVERRIDE to
  * "-GL_NV_primitive_restart" to test that.
  */


 struct sub_primitive
 {
    GLuint start;
    GLuint count;
    GLuint min_index;
    GLuint max_index;
 };


 /**
  * Scan the elements array to find restart indexes.  Return an array
  * of struct sub_primitive to indicate how to draw the sub-primitives
  * are delineated by the restart index.
  */
 static struct sub_primitive *
 find_sub_primitives(const void *elements, unsigned element_size,
                     unsigned start, unsigned end, unsigned restart_index,
                     unsigned *num_sub_prims)
 {
    const unsigned max_prims = end - start;
    struct sub_primitive *sub_prims;
    unsigned i, cur_start, cur_count;
    GLuint scan_index;
    unsigned scan_num;

    sub_prims =
       malloc(max_prims * sizeof(struct sub_primitive));

    if (!sub_prims) {
       *num_sub_prims = 0;
       return NULL;
    }

    cur_start = start;
    cur_count = 0;
    scan_num = 0;

 #define IB_INDEX_READ(TYPE, INDEX) (((const GL##TYPE *) elements)[INDEX])

 #define SCAN_ELEMENTS(TYPE) \
    sub_prims[scan_num].min_index = (GL##TYPE) 0xffffffff; \
    sub_prims[scan_num].max_index = 0; \
    for (i = start; i < end; i++) { \
       scan_index = IB_INDEX_READ(TYPE, i); \
       if (scan_index == restart_index) { \
          if (cur_count > 0) { \
             assert(scan_num < max_prims); \
             sub_prims[scan_num].start = cur_start; \
             sub_prims[scan_num].count = cur_count; \
             scan_num++; \
             sub_prims[scan_num].min_index = (GL##TYPE) 0xffffffff; \
             sub_prims[scan_num].max_index = 0; \
          } \
          cur_start = i + 1; \
          cur_count = 0; \
       } \
       else { \
          UPDATE_MIN2(sub_prims[scan_num].min_index, scan_index); \
          UPDATE_MAX2(sub_prims[scan_num].max_index, scan_index); \
          cur_count++; \
       } \
    } \
    if (cur_count > 0) { \
       assert(scan_num < max_prims); \
       sub_prims[scan_num].start = cur_start; \
       sub_prims[scan_num].count = cur_count; \
       scan_num++; \
    }

    switch (element_size) {
    case 1:
       SCAN_ELEMENTS(ubyte);
       break;
    case 2:
       SCAN_ELEMENTS(ushort);
       break;
    case 4:
       SCAN_ELEMENTS(uint);
       break;
    default:
       assert(0 && "bad index_size in find_sub_primitives()");
    }

 #undef SCAN_ELEMENTS

    *num_sub_prims = scan_num;

    return sub_prims;
 }


 /**
  * Handle primitive restart in software.
  *
  * This function breaks up calls into the driver so primitive restart
  * support is not required in the driver.
  */
 void
 vbo_sw_primitive_restart(struct gl_context *ctx,
                          const struct _mesa_prim *prims,
                          GLuint nr_prims,
                          const struct _mesa_index_buffer *ib,
                          struct gl_buffer_object *indirect)
 {
    GLuint prim_num;
    struct _mesa_prim new_prim;
    struct _mesa_index_buffer new_ib;
    struct sub_primitive *sub_prims;
    struct sub_primitive *sub_prim;
    GLuint num_sub_prims;
    GLuint sub_prim_num;
    GLuint end_index;
    GLuint sub_end_index;
    GLuint restart_index = _mesa_primitive_restart_index(ctx, ib->index_size);
    struct _mesa_prim temp_prim;
    struct vbo_context *vbo = vbo_context(ctx);
    vbo_draw_func draw_prims_func = vbo->draw_prims;
    GLboolean map_ib = ib->obj->Name && !ib->obj->Mappings[MAP_INTERNAL].Pointer;
    void *ptr;

    /* If there is an indirect buffer, map it and extract the draw params */
    if (indirect && prims[0].is_indirect) {
       const uint32_t *indirect_params;
       if (!ctx->Driver.MapBufferRange(ctx, 0, indirect->Size, GL_MAP_READ_BIT,
                                       indirect, MAP_INTERNAL)) {

          /* something went wrong with mapping, give up */
          _mesa_error(ctx, GL_OUT_OF_MEMORY,
                      "failed to map indirect buffer for sw primitive restart");
          return;
       }

       assert(nr_prims == 1);
       new_prim = prims[0];
       indirect_params = (const uint32_t *)
                         ADD_POINTERS(indirect->Mappings[MAP_INTERNAL].Pointer,
                                      new_prim.indirect_offset);

       new_prim.is_indirect = 0;
       new_prim.count = indirect_params[0];
       new_prim.num_instances = indirect_params[1];
       new_prim.start = indirect_params[2];
       new_prim.basevertex = indirect_params[3];
       new_prim.base_instance = indirect_params[4];

       new_ib = *ib;
       new_ib.count = new_prim.count;

       prims = &new_prim;
       ib = &new_ib;

       ctx->Driver.UnmapBuffer(ctx, indirect, MAP_INTERNAL);
    }

    /* Find the sub-primitives. These are regions in the index buffer which
     * are split based on the primitive restart index value.
     */
    if (map_ib) {
       ctx->Driver.MapBufferRange(ctx, 0, ib->obj->Size, GL_MAP_READ_BIT,
                                  ib->obj, MAP_INTERNAL);
    }

    ptr = ADD_POINTERS(ib->obj->Mappings[MAP_INTERNAL].Pointer, ib->ptr);

    sub_prims = find_sub_primitives(ptr, ib->index_size,
                                    0, ib->count, restart_index,
                                    &num_sub_prims);

    if (map_ib) {
       ctx->Driver.UnmapBuffer(ctx, ib->obj, MAP_INTERNAL);
    }

    /* Loop over the primitives, and use the located sub-primitives to draw
     * each primitive with a break to implement each primitive restart.
     */
    for (prim_num = 0; prim_num < nr_prims; prim_num++) {
       end_index = prims[prim_num].start + prims[prim_num].count;
       memcpy(&temp_prim, &prims[prim_num], sizeof (temp_prim));
       /* Loop over the sub-primitives drawing sub-ranges of the primitive. */
       for (sub_prim_num = 0; sub_prim_num < num_sub_prims; sub_prim_num++) {
          sub_prim = &sub_prims[sub_prim_num];
          sub_end_index = sub_prim->start + sub_prim->count;
          if (prims[prim_num].start <= sub_prim->start) {
             temp_prim.start = MAX2(prims[prim_num].start, sub_prim->start);
             temp_prim.count = MIN2(sub_end_index, end_index) - temp_prim.start;
             if ((temp_prim.start == sub_prim->start) &&
                 (temp_prim.count == sub_prim->count)) {
                draw_prims_func(ctx, &temp_prim, 1, ib,
                                GL_TRUE, sub_prim->min_index, sub_prim->max_index,
                                NULL, 0, NULL);
             } else {
                draw_prims_func(ctx, &temp_prim, 1, ib,
                                GL_FALSE, -1, -1,
                                NULL, 0, NULL);
             }
          }
          if (sub_end_index >= end_index) {
             break;
          }
       }
    }

    free(sub_prims);
 }
	/*
	* Copyright 2007 VMware, Inc.
	* All Rights Reserved.
	*
	* 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.
	*
	* Authors:
	* Jordan Justen <jordan.l.justen@intel.com>
	*
	*/

	#include "main/imports.h"
	#include "main/bufferobj.h"
	#include "main/macros.h"
	#include "main/varray.h"

	#include "vbo.h"
	#include "vbo_context.h"

	#define UPDATE_MIN2(a, b) (a) = MIN2((a), (b))
	#define UPDATE_MAX2(a, b) (a) = MAX2((a), (b))

	/*
	* Notes on primitive restart:
	* The code below is used when the driver does not fully support primitive
	* restart (for example, if it only does restart index of ~0).
	*
	* We map the index buffer, find the restart indexes, unmap
	* the index buffer then draw the sub-primitives delineated by the restarts.
	*
	* A couple possible optimizations:
	* 1. Save the list of sub-primitive (start, count) values in a list attached
	* to the index buffer for re-use in subsequent draws. The list would be
	* invalidated when the contents of the buffer changed.
	* 2. If drawing triangle strips or quad strips, create a new index buffer
	* that uses duplicated vertices to render the disjoint strips as one
	* long strip. We'd have to be careful to avoid using too much memory
	* for this.
	*
	* Finally, some apps might perform better if they don't use primitive restart
	* at all rather than this fallback path. Set MESA_EXTENSION_OVERRIDE to
	* "-GL_NV_primitive_restart" to test that.
	*/


	struct sub_primitive
	{
	GLuint start;
	GLuint count;
	GLuint min_index;
	GLuint max_index;
	};


	/**
	* Scan the elements array to find restart indexes. Return an array
	* of struct sub_primitive to indicate how to draw the sub-primitives
	* are delineated by the restart index.
	*/
	static struct sub_primitive *
	find_sub_primitives(const void *elements, unsigned element_size,
	unsigned start, unsigned end, unsigned restart_index,
	unsigned *num_sub_prims)
	{
	const unsigned max_prims = end - start;
	struct sub_primitive *sub_prims;
	unsigned i, cur_start, cur_count;
	GLuint scan_index;
	unsigned scan_num;

	sub_prims =
	malloc(max_prims * sizeof(struct sub_primitive));

	if (!sub_prims) {
	*num_sub_prims = 0;
	return NULL;
	}

	cur_start = start;
	cur_count = 0;
	scan_num = 0;

	#define IB_INDEX_READ(TYPE, INDEX) (((const GL##TYPE *) elements)[INDEX])

	#define SCAN_ELEMENTS(TYPE) \
	sub_prims[scan_num].min_index = (GL##TYPE) 0xffffffff; \
	sub_prims[scan_num].max_index = 0; \
	for (i = start; i < end; i++) { \
	scan_index = IB_INDEX_READ(TYPE, i); \
	if (scan_index == restart_index) { \
	if (cur_count > 0) { \
	assert(scan_num < max_prims); \
	sub_prims[scan_num].start = cur_start; \
	sub_prims[scan_num].count = cur_count; \
	scan_num++; \
	sub_prims[scan_num].min_index = (GL##TYPE) 0xffffffff; \
	sub_prims[scan_num].max_index = 0; \
	} \
	cur_start = i + 1; \
	cur_count = 0; \
	} \
	else { \
	UPDATE_MIN2(sub_prims[scan_num].min_index, scan_index); \
	UPDATE_MAX2(sub_prims[scan_num].max_index, scan_index); \
	cur_count++; \
	} \
	} \
	if (cur_count > 0) { \
	assert(scan_num < max_prims); \
	sub_prims[scan_num].start = cur_start; \
	sub_prims[scan_num].count = cur_count; \
	scan_num++; \
	}

	switch (element_size) {
	case 1:
	SCAN_ELEMENTS(ubyte);
	break;
	case 2:
	SCAN_ELEMENTS(ushort);
	break;
	case 4:
	SCAN_ELEMENTS(uint);
	break;
	default:
	assert(0 && "bad index_size in find_sub_primitives()");
	}

	#undef SCAN_ELEMENTS

	*num_sub_prims = scan_num;

	return sub_prims;
	}


	/**
	* Handle primitive restart in software.
	*
	* This function breaks up calls into the driver so primitive restart
	* support is not required in the driver.
	*/
	void
	vbo_sw_primitive_restart(struct gl_context *ctx,
	const struct _mesa_prim *prims,
	GLuint nr_prims,
	const struct _mesa_index_buffer *ib,
	struct gl_buffer_object *indirect)
	{
	GLuint prim_num;
	struct _mesa_prim new_prim;
	struct _mesa_index_buffer new_ib;
	struct sub_primitive *sub_prims;
	struct sub_primitive *sub_prim;
	GLuint num_sub_prims;
	GLuint sub_prim_num;
	GLuint end_index;
	GLuint sub_end_index;
	GLuint restart_index = _mesa_primitive_restart_index(ctx, ib->index_size);
	struct _mesa_prim temp_prim;
	struct vbo_context *vbo = vbo_context(ctx);
	vbo_draw_func draw_prims_func = vbo->draw_prims;
	GLboolean map_ib = ib->obj->Name && !ib->obj->Mappings[MAP_INTERNAL].Pointer;
	void *ptr;

	/* If there is an indirect buffer, map it and extract the draw params */
	if (indirect && prims[0].is_indirect) {
	const uint32_t *indirect_params;
	if (!ctx->Driver.MapBufferRange(ctx, 0, indirect->Size, GL_MAP_READ_BIT,
	indirect, MAP_INTERNAL)) {

	/* something went wrong with mapping, give up */
	_mesa_error(ctx, GL_OUT_OF_MEMORY,
	"failed to map indirect buffer for sw primitive restart");
	return;
	}

	assert(nr_prims == 1);
	new_prim = prims[0];
	indirect_params = (const uint32_t *)
	ADD_POINTERS(indirect->Mappings[MAP_INTERNAL].Pointer,
	new_prim.indirect_offset);

	new_prim.is_indirect = 0;
	new_prim.count = indirect_params[0];
	new_prim.num_instances = indirect_params[1];
	new_prim.start = indirect_params[2];
	new_prim.basevertex = indirect_params[3];
	new_prim.base_instance = indirect_params[4];

	new_ib = *ib;
	new_ib.count = new_prim.count;

	prims = &new_prim;
	ib = &new_ib;

	ctx->Driver.UnmapBuffer(ctx, indirect, MAP_INTERNAL);
	}

	/* Find the sub-primitives. These are regions in the index buffer which
	* are split based on the primitive restart index value.
	*/
	if (map_ib) {
	ctx->Driver.MapBufferRange(ctx, 0, ib->obj->Size, GL_MAP_READ_BIT,
	ib->obj, MAP_INTERNAL);
	}

	ptr = ADD_POINTERS(ib->obj->Mappings[MAP_INTERNAL].Pointer, ib->ptr);

	sub_prims = find_sub_primitives(ptr, ib->index_size,
	0, ib->count, restart_index,
	&num_sub_prims);

	if (map_ib) {
	ctx->Driver.UnmapBuffer(ctx, ib->obj, MAP_INTERNAL);
	}

	/* Loop over the primitives, and use the located sub-primitives to draw
	* each primitive with a break to implement each primitive restart.
	*/
	for (prim_num = 0; prim_num < nr_prims; prim_num++) {
	end_index = prims[prim_num].start + prims[prim_num].count;
	memcpy(&temp_prim, &prims[prim_num], sizeof (temp_prim));
	/* Loop over the sub-primitives drawing sub-ranges of the primitive. */
	for (sub_prim_num = 0; sub_prim_num < num_sub_prims; sub_prim_num++) {
	sub_prim = &sub_prims[sub_prim_num];
	sub_end_index = sub_prim->start + sub_prim->count;
	if (prims[prim_num].start <= sub_prim->start) {
	temp_prim.start = MAX2(prims[prim_num].start, sub_prim->start);
	temp_prim.count = MIN2(sub_end_index, end_index) - temp_prim.start;
	if ((temp_prim.start == sub_prim->start) &&
	(temp_prim.count == sub_prim->count)) {
	draw_prims_func(ctx, &temp_prim, 1, ib,
	GL_TRUE, sub_prim->min_index, sub_prim->max_index,
	NULL, 0, NULL);
	} else {
	draw_prims_func(ctx, &temp_prim, 1, ib,
	GL_FALSE, -1, -1,
	NULL, 0, NULL);
	}
	}
	if (sub_end_index >= end_index) {
	break;
	}
	}
	}

	free(sub_prims);
	}