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

 /*
  * Mesa 3-D graphics library
  *
  * Copyright (C) 1999-2008  Brian Paul   All Rights Reserved.
  *
  * 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 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:
  *    Keith Whitwell <keithw@vmware.com>
  */

 #include <stdbool.h>
 #include <stdio.h>
 #include "main/arrayobj.h"
 #include "main/glheader.h"
 #include "main/bufferobj.h"
 #include "main/context.h"
 #include "main/enums.h"
 #include "main/state.h"
 #include "main/varray.h"
 #include "main/vtxfmt.h"

 #include "vbo_noop.h"
 #include "vbo_private.h"


 static void
 vbo_exec_debug_verts(struct vbo_exec_context *exec)
 {
    GLuint count = exec->vtx.vert_count;
    GLuint i;

    printf("%s: %u vertices %d primitives, %d vertsize\n",
           __func__,
           count,
           exec->vtx.prim_count,
           exec->vtx.vertex_size);

    for (i = 0 ; i < exec->vtx.prim_count ; i++) {
       struct _mesa_prim *prim = &exec->vtx.prim[i];
       printf("   prim %d: %s %d..%d %s %s\n",
              i,
              _mesa_lookup_prim_by_nr(prim->mode),
              prim->start,
              prim->start + prim->count,
              prim->begin ? "BEGIN" : "(wrap)",
              prim->end ? "END" : "(wrap)");
    }
 }


 /**
  * Copy zero, one or two vertices from the current vertex buffer into
  * the temporary "copy" buffer.
  * This is used when a single primitive overflows a vertex buffer and
  * we need to continue the primitive in a new vertex buffer.
  * The temporary "copy" buffer holds the vertices which need to get
  * copied from the old buffer to the new one.
  */
 static GLuint
 vbo_copy_vertices(struct vbo_exec_context *exec)
 {
    struct _mesa_prim *last_prim = &exec->vtx.prim[exec->vtx.prim_count - 1];
    const GLuint nr = last_prim->count;
    GLuint ovf, i;
    const GLuint sz = exec->vtx.vertex_size;
    fi_type *dst = exec->vtx.copied.buffer;
    const fi_type *src = exec->vtx.buffer_map + last_prim->start * sz;

    switch (exec->ctx->Driver.CurrentExecPrimitive) {
    case GL_POINTS:
       return 0;
    case GL_LINES:
       ovf = nr&1;
       for (i = 0 ; i < ovf ; i++)
          memcpy(dst+i*sz, src+(nr-ovf+i)*sz, sz * sizeof(GLfloat));
       return i;
    case GL_TRIANGLES:
       ovf = nr%3;
       for (i = 0 ; i < ovf ; i++)
          memcpy(dst+i*sz, src+(nr-ovf+i)*sz, sz * sizeof(GLfloat));
       return i;
    case GL_QUADS:
       ovf = nr&3;
       for (i = 0 ; i < ovf ; i++)
          memcpy(dst+i*sz, src+(nr-ovf+i)*sz, sz * sizeof(GLfloat));
       return i;
    case GL_LINE_STRIP:
       if (nr == 0) {
          return 0;
       }
       else {
          memcpy(dst, src+(nr-1)*sz, sz * sizeof(GLfloat));
          return 1;
       }
    case GL_LINE_LOOP:
       if (last_prim->begin == 0) {
          /* We're dealing with the second or later section of a split/wrapped
           * GL_LINE_LOOP.  Since we're converting line loops to line strips,
           * we've already increment the last_prim->start counter by one to
           * skip the 0th vertex in the loop.  We need to undo that (effectively
           * subtract one from last_prim->start) so that we copy the 0th vertex
           * to the next vertex buffer.
           */
          assert(last_prim->start > 0);
          src -= sz;
       }
       /* fall-through */
    case GL_TRIANGLE_FAN:
    case GL_POLYGON:
       if (nr == 0) {
          return 0;
       }
       else if (nr == 1) {
          memcpy(dst, src+0, sz * sizeof(GLfloat));
          return 1;
       }
       else {
          memcpy(dst, src+0, sz * sizeof(GLfloat));
          memcpy(dst+sz, src+(nr-1)*sz, sz * sizeof(GLfloat));
          return 2;
       }
    case GL_TRIANGLE_STRIP:
       /* no parity issue, but need to make sure the tri is not drawn twice */
       if (nr & 1) {
          last_prim->count--;
       }
       /* fallthrough */
    case GL_QUAD_STRIP:
       switch (nr) {
       case 0:
          ovf = 0;
          break;
       case 1:
          ovf = 1;
          break;
       default:
          ovf = 2 + (nr & 1);
          break;
       }
       for (i = 0 ; i < ovf ; i++)
          memcpy(dst+i*sz, src+(nr-ovf+i)*sz, sz * sizeof(GLfloat));
       return i;
    case PRIM_OUTSIDE_BEGIN_END:
       return 0;
    default:
       unreachable("Unexpected primitive type");
       return 0;
    }
 }


 /* TODO: populate these as the vertex is defined:
  */
 static void
 vbo_exec_bind_arrays(struct gl_context *ctx)
 {
    struct vbo_context *vbo = vbo_context(ctx);
    struct gl_vertex_array_object *vao = vbo->VAO;
    struct vbo_exec_context *exec = &vbo->exec;

    GLintptr buffer_offset;
    if (_mesa_is_bufferobj(exec->vtx.bufferobj)) {
       assert(exec->vtx.bufferobj->Mappings[MAP_INTERNAL].Pointer);
       buffer_offset = exec->vtx.bufferobj->Mappings[MAP_INTERNAL].Offset;
    } else {
       /* Ptr into ordinary app memory */
       buffer_offset = (GLbyte *)exec->vtx.buffer_map - (GLbyte *)NULL;
    }

    const gl_vertex_processing_mode mode = ctx->VertexProgram._VPMode;

    /* Compute the bitmasks of vao_enabled arrays */
    GLbitfield vao_enabled = _vbo_get_vao_enabled_from_vbo(mode, exec->vtx.enabled);

    /* At first disable arrays no longer needed */
    _mesa_disable_vertex_array_attribs(ctx, vao, VERT_BIT_ALL & ~vao_enabled);
    assert((~vao_enabled & vao->Enabled) == 0);

    /* Bind the buffer object */
    const GLuint stride = exec->vtx.vertex_size*sizeof(GLfloat);
    _mesa_bind_vertex_buffer(ctx, vao, 0, exec->vtx.bufferobj, buffer_offset,
                             stride);

    /* Retrieve the mapping from VBO_ATTRIB to VERT_ATTRIB space
     * Note that the position/generic0 aliasing is done in the VAO.
     */
    const GLubyte *const vao_to_vbo_map = _vbo_attribute_alias_map[mode];
    /* Now set the enabled arrays */
    GLbitfield mask = vao_enabled;
    while (mask) {
       const int vao_attr = u_bit_scan(&mask);
       const GLubyte vbo_attr = vao_to_vbo_map[vao_attr];

       const GLubyte size = exec->vtx.attrsz[vbo_attr];
       const GLenum16 type = exec->vtx.attrtype[vbo_attr];
       const GLuint offset = (GLuint)((GLbyte *)exec->vtx.attrptr[vbo_attr] -
                                      (GLbyte *)exec->vtx.vertex);
       assert(offset <= ctx->Const.MaxVertexAttribRelativeOffset);

       /* Set and enable */
       _vbo_set_attrib_format(ctx, vao, vao_attr, buffer_offset,
                              size, type, offset);

       /* The vao is initially created with all bindings set to 0. */
       assert(vao->VertexAttrib[vao_attr].BufferBindingIndex == 0);
    }
    _mesa_enable_vertex_array_attribs(ctx, vao, vao_enabled);
    assert(vao_enabled == vao->Enabled);
    assert(!_mesa_is_bufferobj(exec->vtx.bufferobj) ||
           (vao_enabled & ~vao->VertexAttribBufferMask) == 0);

    _mesa_set_draw_vao(ctx, vao, _vbo_get_vao_filter(mode));
 }


 /**
  * Unmap the VBO.  This is called before drawing.
  */
 static void
 vbo_exec_vtx_unmap(struct vbo_exec_context *exec)
 {
    if (_mesa_is_bufferobj(exec->vtx.bufferobj)) {
       struct gl_context *ctx = exec->ctx;

       if (ctx->Driver.FlushMappedBufferRange) {
          GLintptr offset = exec->vtx.buffer_used -
                            exec->vtx.bufferobj->Mappings[MAP_INTERNAL].Offset;
          GLsizeiptr length = (exec->vtx.buffer_ptr - exec->vtx.buffer_map) *
                              sizeof(float);

          if (length)
             ctx->Driver.FlushMappedBufferRange(ctx, offset, length,
                                                exec->vtx.bufferobj,
                                                MAP_INTERNAL);
       }

       exec->vtx.buffer_used += (exec->vtx.buffer_ptr -
                                 exec->vtx.buffer_map) * sizeof(float);

       assert(exec->vtx.buffer_used <= VBO_VERT_BUFFER_SIZE);
       assert(exec->vtx.buffer_ptr != NULL);

       ctx->Driver.UnmapBuffer(ctx, exec->vtx.bufferobj, MAP_INTERNAL);
       exec->vtx.buffer_map = NULL;
       exec->vtx.buffer_ptr = NULL;
       exec->vtx.max_vert = 0;
    }
 }


 /**
  * Map the vertex buffer to begin storing glVertex, glColor, etc data.
  */
 void
 vbo_exec_vtx_map(struct vbo_exec_context *exec)
 {
    struct gl_context *ctx = exec->ctx;
    const GLenum accessRange = GL_MAP_WRITE_BIT |  /* for MapBufferRange */
                               GL_MAP_INVALIDATE_RANGE_BIT |
                               GL_MAP_UNSYNCHRONIZED_BIT |
                               GL_MAP_FLUSH_EXPLICIT_BIT |
                               MESA_MAP_NOWAIT_BIT;
    const GLenum usage = GL_STREAM_DRAW_ARB;

    if (!_mesa_is_bufferobj(exec->vtx.bufferobj))
       return;

    assert(!exec->vtx.buffer_map);
    assert(!exec->vtx.buffer_ptr);

    if (VBO_VERT_BUFFER_SIZE > exec->vtx.buffer_used + 1024) {
       /* The VBO exists and there's room for more */
       if (exec->vtx.bufferobj->Size > 0) {
          exec->vtx.buffer_map = (fi_type *)
             ctx->Driver.MapBufferRange(ctx,
                                        exec->vtx.buffer_used,
                                        VBO_VERT_BUFFER_SIZE
                                        - exec->vtx.buffer_used,
                                        accessRange,
                                        exec->vtx.bufferobj,
                                        MAP_INTERNAL);
          exec->vtx.buffer_ptr = exec->vtx.buffer_map;
       }
       else {
          exec->vtx.buffer_ptr = exec->vtx.buffer_map = NULL;
       }
    }

    if (!exec->vtx.buffer_map) {
       /* Need to allocate a new VBO */
       exec->vtx.buffer_used = 0;

       if (ctx->Driver.BufferData(ctx, GL_ARRAY_BUFFER_ARB,
                                  VBO_VERT_BUFFER_SIZE,
                                  NULL, usage,
                                  GL_MAP_WRITE_BIT |
                                  GL_DYNAMIC_STORAGE_BIT |
                                  GL_CLIENT_STORAGE_BIT,
                                  exec->vtx.bufferobj)) {
          /* buffer allocation worked, now map the buffer */
          exec->vtx.buffer_map =
             (fi_type *)ctx->Driver.MapBufferRange(ctx,
                                                   0, VBO_VERT_BUFFER_SIZE,
                                                   accessRange,
                                                   exec->vtx.bufferobj,
                                                   MAP_INTERNAL);
       }
       else {
          _mesa_error(ctx, GL_OUT_OF_MEMORY, "VBO allocation");
          exec->vtx.buffer_map = NULL;
       }
    }

    exec->vtx.buffer_ptr = exec->vtx.buffer_map;

    if (!exec->vtx.buffer_map) {
       /* out of memory */
       _mesa_install_exec_vtxfmt(ctx, &exec->vtxfmt_noop);
    }
    else {
       if (_mesa_using_noop_vtxfmt(ctx->Exec)) {
          /* The no-op functions are installed so switch back to regular
           * functions.  We do this test just to avoid frequent and needless
           * calls to _mesa_install_exec_vtxfmt().
           */
          _mesa_install_exec_vtxfmt(ctx, &exec->vtxfmt);
       }
    }

    if (0)
       printf("map %d..\n", exec->vtx.buffer_used);
 }


 /**
  * Execute the buffer and save copied verts.
  * \param keep_unmapped  if true, leave the VBO unmapped when we're done.
  */
 void
 vbo_exec_vtx_flush(struct vbo_exec_context *exec, GLboolean keepUnmapped)
 {
    if (0)
       vbo_exec_debug_verts(exec);

    if (exec->vtx.prim_count &&
        exec->vtx.vert_count) {

       exec->vtx.copied.nr = vbo_copy_vertices(exec);

       if (exec->vtx.copied.nr != exec->vtx.vert_count) {
          struct gl_context *ctx = exec->ctx;

          /* Before the update_state() as this may raise _NEW_VARYING_VP_INPUTS
           * from _mesa_set_varying_vp_inputs().
           */
          vbo_exec_bind_arrays(ctx);

          if (ctx->NewState)
             _mesa_update_state(ctx);

          vbo_exec_vtx_unmap(exec);

          assert(ctx->NewState == 0);

          if (0)
             printf("%s %d %d\n", __func__, exec->vtx.prim_count,
                    exec->vtx.vert_count);

          ctx->Driver.Draw(ctx, exec->vtx.prim, exec->vtx.prim_count,
                           NULL, GL_TRUE, 0, exec->vtx.vert_count - 1,
                           NULL, 0, NULL);

          /* Get new storage -- unless asked not to. */
          if (!keepUnmapped)
             vbo_exec_vtx_map(exec);
       }
    }

    /* May have to unmap explicitly if we didn't draw:
     */
    if (keepUnmapped && exec->vtx.buffer_map) {
       vbo_exec_vtx_unmap(exec);
    }

    if (keepUnmapped || exec->vtx.vertex_size == 0)
       exec->vtx.max_vert = 0;
    else
       exec->vtx.max_vert = vbo_compute_max_verts(exec);

    exec->vtx.buffer_ptr = exec->vtx.buffer_map;
    exec->vtx.prim_count = 0;
    exec->vtx.vert_count = 0;
 }
	/*
	* Mesa 3-D graphics library
	*
	* Copyright (C) 1999-2008 Brian Paul All Rights Reserved.
	*
	* 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 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:
	* Keith Whitwell <keithw@vmware.com>
	*/

	#include <stdbool.h>
	#include <stdio.h>
	#include "main/arrayobj.h"
	#include "main/glheader.h"
	#include "main/bufferobj.h"
	#include "main/context.h"
	#include "main/enums.h"
	#include "main/state.h"
	#include "main/varray.h"
	#include "main/vtxfmt.h"

	#include "vbo_noop.h"
	#include "vbo_private.h"


	static void
	vbo_exec_debug_verts(struct vbo_exec_context *exec)
	{
	GLuint count = exec->vtx.vert_count;
	GLuint i;

	printf("%s: %u vertices %d primitives, %d vertsize\n",
	__func__,
	count,
	exec->vtx.prim_count,
	exec->vtx.vertex_size);

	for (i = 0 ; i < exec->vtx.prim_count ; i++) {
	struct _mesa_prim *prim = &exec->vtx.prim[i];
	printf(" prim %d: %s %d..%d %s %s\n",
	i,
	_mesa_lookup_prim_by_nr(prim->mode),
	prim->start,
	prim->start + prim->count,
	prim->begin ? "BEGIN" : "(wrap)",
	prim->end ? "END" : "(wrap)");
	}
	}


	/**
	* Copy zero, one or two vertices from the current vertex buffer into
	* the temporary "copy" buffer.
	* This is used when a single primitive overflows a vertex buffer and
	* we need to continue the primitive in a new vertex buffer.
	* The temporary "copy" buffer holds the vertices which need to get
	* copied from the old buffer to the new one.
	*/
	static GLuint
	vbo_copy_vertices(struct vbo_exec_context *exec)
	{
	struct _mesa_prim *last_prim = &exec->vtx.prim[exec->vtx.prim_count - 1];
	const GLuint nr = last_prim->count;
	GLuint ovf, i;
	const GLuint sz = exec->vtx.vertex_size;
	fi_type *dst = exec->vtx.copied.buffer;
	const fi_type src = exec->vtx.buffer_map + last_prim->start sz;

	switch (exec->ctx->Driver.CurrentExecPrimitive) {
	case GL_POINTS:
	return 0;
	case GL_LINES:
	ovf = nr&1;
	for (i = 0 ; i < ovf ; i++)
	memcpy(dst+isz, src+(nr-ovf+i)sz, sz * sizeof(GLfloat));
	return i;
	case GL_TRIANGLES:
	ovf = nr%3;
	for (i = 0 ; i < ovf ; i++)
	memcpy(dst+isz, src+(nr-ovf+i)sz, sz * sizeof(GLfloat));
	return i;
	case GL_QUADS:
	ovf = nr&3;
	for (i = 0 ; i < ovf ; i++)
	memcpy(dst+isz, src+(nr-ovf+i)sz, sz * sizeof(GLfloat));
	return i;
	case GL_LINE_STRIP:
	if (nr == 0) {
	return 0;
	}
	else {
	memcpy(dst, src+(nr-1)sz, sz sizeof(GLfloat));
	return 1;
	}
	case GL_LINE_LOOP:
	if (last_prim->begin == 0) {
	/* We're dealing with the second or later section of a split/wrapped
	* GL_LINE_LOOP. Since we're converting line loops to line strips,
	* we've already increment the last_prim->start counter by one to
	* skip the 0th vertex in the loop. We need to undo that (effectively
	* subtract one from last_prim->start) so that we copy the 0th vertex
	* to the next vertex buffer.
	*/
	assert(last_prim->start > 0);
	src -= sz;
	}
	/* fall-through */
	case GL_TRIANGLE_FAN:
	case GL_POLYGON:
	if (nr == 0) {
	return 0;
	}
	else if (nr == 1) {
	memcpy(dst, src+0, sz * sizeof(GLfloat));
	return 1;
	}
	else {
	memcpy(dst, src+0, sz * sizeof(GLfloat));
	memcpy(dst+sz, src+(nr-1)sz, sz sizeof(GLfloat));
	return 2;
	}
	case GL_TRIANGLE_STRIP:
	/* no parity issue, but need to make sure the tri is not drawn twice */
	if (nr & 1) {
	last_prim->count--;
	}
	/* fallthrough */
	case GL_QUAD_STRIP:
	switch (nr) {
	case 0:
	ovf = 0;
	break;
	case 1:
	ovf = 1;
	break;
	default:
	ovf = 2 + (nr & 1);
	break;
	}
	for (i = 0 ; i < ovf ; i++)
	memcpy(dst+isz, src+(nr-ovf+i)sz, sz * sizeof(GLfloat));
	return i;
	case PRIM_OUTSIDE_BEGIN_END:
	return 0;
	default:
	unreachable("Unexpected primitive type");
	return 0;
	}
	}



	/* TODO: populate these as the vertex is defined:
	*/
	static void
	vbo_exec_bind_arrays(struct gl_context *ctx)
	{
	struct vbo_context *vbo = vbo_context(ctx);
	struct gl_vertex_array_object *vao = vbo->VAO;
	struct vbo_exec_context *exec = &vbo->exec;

	GLintptr buffer_offset;
	if (_mesa_is_bufferobj(exec->vtx.bufferobj)) {
	assert(exec->vtx.bufferobj->Mappings[MAP_INTERNAL].Pointer);
	buffer_offset = exec->vtx.bufferobj->Mappings[MAP_INTERNAL].Offset;
	} else {
	/* Ptr into ordinary app memory */
	buffer_offset = (GLbyte )exec->vtx.buffer_map - (GLbyte )NULL;
	}

	const gl_vertex_processing_mode mode = ctx->VertexProgram._VPMode;

	/* Compute the bitmasks of vao_enabled arrays */
	GLbitfield vao_enabled = _vbo_get_vao_enabled_from_vbo(mode, exec->vtx.enabled);

	/* At first disable arrays no longer needed */
	_mesa_disable_vertex_array_attribs(ctx, vao, VERT_BIT_ALL & ~vao_enabled);
	assert((~vao_enabled & vao->Enabled) == 0);

	/* Bind the buffer object */
	const GLuint stride = exec->vtx.vertex_size*sizeof(GLfloat);
	_mesa_bind_vertex_buffer(ctx, vao, 0, exec->vtx.bufferobj, buffer_offset,
	stride);

	/* Retrieve the mapping from VBO_ATTRIB to VERT_ATTRIB space
	* Note that the position/generic0 aliasing is done in the VAO.
	*/
	const GLubyte *const vao_to_vbo_map = _vbo_attribute_alias_map[mode];
	/* Now set the enabled arrays */
	GLbitfield mask = vao_enabled;
	while (mask) {
	const int vao_attr = u_bit_scan(&mask);
	const GLubyte vbo_attr = vao_to_vbo_map[vao_attr];

	const GLubyte size = exec->vtx.attrsz[vbo_attr];
	const GLenum16 type = exec->vtx.attrtype[vbo_attr];
	const GLuint offset = (GLuint)((GLbyte *)exec->vtx.attrptr[vbo_attr] -
	(GLbyte *)exec->vtx.vertex);
	assert(offset <= ctx->Const.MaxVertexAttribRelativeOffset);

	/* Set and enable */
	_vbo_set_attrib_format(ctx, vao, vao_attr, buffer_offset,
	size, type, offset);

	/* The vao is initially created with all bindings set to 0. */
	assert(vao->VertexAttrib[vao_attr].BufferBindingIndex == 0);
	}
	_mesa_enable_vertex_array_attribs(ctx, vao, vao_enabled);
	assert(vao_enabled == vao->Enabled);
	assert(!_mesa_is_bufferobj(exec->vtx.bufferobj) \|\|
	(vao_enabled & ~vao->VertexAttribBufferMask) == 0);

	_mesa_set_draw_vao(ctx, vao, _vbo_get_vao_filter(mode));
	}


	/**
	* Unmap the VBO. This is called before drawing.
	*/
	static void
	vbo_exec_vtx_unmap(struct vbo_exec_context *exec)
	{
	if (_mesa_is_bufferobj(exec->vtx.bufferobj)) {
	struct gl_context *ctx = exec->ctx;

	if (ctx->Driver.FlushMappedBufferRange) {
	GLintptr offset = exec->vtx.buffer_used -
	exec->vtx.bufferobj->Mappings[MAP_INTERNAL].Offset;
	GLsizeiptr length = (exec->vtx.buffer_ptr - exec->vtx.buffer_map) *
	sizeof(float);

	if (length)
	ctx->Driver.FlushMappedBufferRange(ctx, offset, length,
	exec->vtx.bufferobj,
	MAP_INTERNAL);
	}

	exec->vtx.buffer_used += (exec->vtx.buffer_ptr -
	exec->vtx.buffer_map) * sizeof(float);

	assert(exec->vtx.buffer_used <= VBO_VERT_BUFFER_SIZE);
	assert(exec->vtx.buffer_ptr != NULL);

	ctx->Driver.UnmapBuffer(ctx, exec->vtx.bufferobj, MAP_INTERNAL);
	exec->vtx.buffer_map = NULL;
	exec->vtx.buffer_ptr = NULL;
	exec->vtx.max_vert = 0;
	}
	}


	/**
	* Map the vertex buffer to begin storing glVertex, glColor, etc data.
	*/
	void
	vbo_exec_vtx_map(struct vbo_exec_context *exec)
	{
	struct gl_context *ctx = exec->ctx;
	const GLenum accessRange = GL_MAP_WRITE_BIT \| /* for MapBufferRange */
	GL_MAP_INVALIDATE_RANGE_BIT \|
	GL_MAP_UNSYNCHRONIZED_BIT \|
	GL_MAP_FLUSH_EXPLICIT_BIT \|
	MESA_MAP_NOWAIT_BIT;
	const GLenum usage = GL_STREAM_DRAW_ARB;

	if (!_mesa_is_bufferobj(exec->vtx.bufferobj))
	return;

	assert(!exec->vtx.buffer_map);
	assert(!exec->vtx.buffer_ptr);

	if (VBO_VERT_BUFFER_SIZE > exec->vtx.buffer_used + 1024) {
	/* The VBO exists and there's room for more */
	if (exec->vtx.bufferobj->Size > 0) {
	exec->vtx.buffer_map = (fi_type *)
	ctx->Driver.MapBufferRange(ctx,
	exec->vtx.buffer_used,
	VBO_VERT_BUFFER_SIZE
	- exec->vtx.buffer_used,
	accessRange,
	exec->vtx.bufferobj,
	MAP_INTERNAL);
	exec->vtx.buffer_ptr = exec->vtx.buffer_map;
	}
	else {
	exec->vtx.buffer_ptr = exec->vtx.buffer_map = NULL;
	}
	}

	if (!exec->vtx.buffer_map) {
	/* Need to allocate a new VBO */
	exec->vtx.buffer_used = 0;

	if (ctx->Driver.BufferData(ctx, GL_ARRAY_BUFFER_ARB,
	VBO_VERT_BUFFER_SIZE,
	NULL, usage,
	GL_MAP_WRITE_BIT \|
	GL_DYNAMIC_STORAGE_BIT \|
	GL_CLIENT_STORAGE_BIT,
	exec->vtx.bufferobj)) {
	/* buffer allocation worked, now map the buffer */
	exec->vtx.buffer_map =
	(fi_type *)ctx->Driver.MapBufferRange(ctx,
	0, VBO_VERT_BUFFER_SIZE,
	accessRange,
	exec->vtx.bufferobj,
	MAP_INTERNAL);
	}
	else {
	_mesa_error(ctx, GL_OUT_OF_MEMORY, "VBO allocation");
	exec->vtx.buffer_map = NULL;
	}
	}

	exec->vtx.buffer_ptr = exec->vtx.buffer_map;

	if (!exec->vtx.buffer_map) {
	/* out of memory */
	_mesa_install_exec_vtxfmt(ctx, &exec->vtxfmt_noop);
	}
	else {
	if (_mesa_using_noop_vtxfmt(ctx->Exec)) {
	/* The no-op functions are installed so switch back to regular
	* functions. We do this test just to avoid frequent and needless
	* calls to _mesa_install_exec_vtxfmt().
	*/
	_mesa_install_exec_vtxfmt(ctx, &exec->vtxfmt);
	}
	}

	if (0)
	printf("map %d..\n", exec->vtx.buffer_used);
	}



	/**
	* Execute the buffer and save copied verts.
	* \param keep_unmapped if true, leave the VBO unmapped when we're done.
	*/
	void
	vbo_exec_vtx_flush(struct vbo_exec_context *exec, GLboolean keepUnmapped)
	{
	if (0)
	vbo_exec_debug_verts(exec);

	if (exec->vtx.prim_count &&
	exec->vtx.vert_count) {

	exec->vtx.copied.nr = vbo_copy_vertices(exec);

	if (exec->vtx.copied.nr != exec->vtx.vert_count) {
	struct gl_context *ctx = exec->ctx;

	/* Before the update_state() as this may raise _NEW_VARYING_VP_INPUTS
	* from _mesa_set_varying_vp_inputs().
	*/
	vbo_exec_bind_arrays(ctx);

	if (ctx->NewState)
	_mesa_update_state(ctx);

	vbo_exec_vtx_unmap(exec);

	assert(ctx->NewState == 0);

	if (0)
	printf("%s %d %d\n", __func__, exec->vtx.prim_count,
	exec->vtx.vert_count);

	ctx->Driver.Draw(ctx, exec->vtx.prim, exec->vtx.prim_count,
	NULL, GL_TRUE, 0, exec->vtx.vert_count - 1,
	NULL, 0, NULL);

	/* Get new storage -- unless asked not to. */
	if (!keepUnmapped)
	vbo_exec_vtx_map(exec);
	}
	}

	/* May have to unmap explicitly if we didn't draw:
	*/
	if (keepUnmapped && exec->vtx.buffer_map) {
	vbo_exec_vtx_unmap(exec);
	}

	if (keepUnmapped \|\| exec->vtx.vertex_size == 0)
	exec->vtx.max_vert = 0;
	else
	exec->vtx.max_vert = vbo_compute_max_verts(exec);

	exec->vtx.buffer_ptr = exec->vtx.buffer_map;
	exec->vtx.prim_count = 0;
	exec->vtx.vert_count = 0;
	}