path: root/src/mesa/state_tracker/st_draw.c

/**************************************************************************
 * 
 * Copyright 2007 Tungsten Graphics, Inc., Cedar Park, Texas.
 * 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, sub license, 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 NON-INFRINGEMENT.
 * IN NO EVENT SHALL TUNGSTEN GRAPHICS AND/OR ITS SUPPLIERS 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 <keith@tungstengraphics.com>
  */

#include "main/imports.h"
#include "main/image.h"

#include "vbo/vbo.h"

#include "st_atom.h"
#include "st_context.h"
#include "st_cb_bufferobjects.h"
#include "st_draw.h"
#include "st_program.h"

#include "pipe/p_context.h"
#include "pipe/p_defines.h"
#include "pipe/p_winsys.h"
#include "pipe/p_inlines.h"

#include "draw/draw_private.h"
#include "draw/draw_context.h"


static GLuint double_types[4] = {
   PIPE_FORMAT_R64_FLOAT,
   PIPE_FORMAT_R64G64_FLOAT,
   PIPE_FORMAT_R64G64B64_FLOAT,
   PIPE_FORMAT_R64G64B64A64_FLOAT
};

static GLuint float_types[4] = {
   PIPE_FORMAT_R32_FLOAT,
   PIPE_FORMAT_R32G32_FLOAT,
   PIPE_FORMAT_R32G32B32_FLOAT,
   PIPE_FORMAT_R32G32B32A32_FLOAT
};

static GLuint uint_types_norm[4] = {
   PIPE_FORMAT_R32_UNORM,
   PIPE_FORMAT_R32G32_UNORM,
   PIPE_FORMAT_R32G32B32_UNORM,
   PIPE_FORMAT_R32G32B32A32_UNORM
};

static GLuint uint_types_scale[4] = {
   PIPE_FORMAT_R32_USCALED,
   PIPE_FORMAT_R32G32_USCALED,
   PIPE_FORMAT_R32G32B32_USCALED,
   PIPE_FORMAT_R32G32B32A32_USCALED
};

static GLuint int_types_norm[4] = {
   PIPE_FORMAT_R32_SNORM,
   PIPE_FORMAT_R32G32_SNORM,
   PIPE_FORMAT_R32G32B32_SNORM,
   PIPE_FORMAT_R32G32B32A32_SNORM
};

static GLuint int_types_scale[4] = {
   PIPE_FORMAT_R32_SSCALED,
   PIPE_FORMAT_R32G32_SSCALED,
   PIPE_FORMAT_R32G32B32_SSCALED,
   PIPE_FORMAT_R32G32B32A32_SSCALED
};

static GLuint ushort_types_norm[4] = {
   PIPE_FORMAT_R16_UNORM,
   PIPE_FORMAT_R16G16_UNORM,
   PIPE_FORMAT_R16G16B16_UNORM,
   PIPE_FORMAT_R16G16B16A16_UNORM
};

static GLuint ushort_types_scale[4] = {
   PIPE_FORMAT_R16_USCALED,
   PIPE_FORMAT_R16G16_USCALED,
   PIPE_FORMAT_R16G16B16_USCALED,
   PIPE_FORMAT_R16G16B16A16_USCALED
};

static GLuint short_types_norm[4] = {
   PIPE_FORMAT_R16_SNORM,
   PIPE_FORMAT_R16G16_SNORM,
   PIPE_FORMAT_R16G16B16_SNORM,
   PIPE_FORMAT_R16G16B16A16_SNORM
};

static GLuint short_types_scale[4] = {
   PIPE_FORMAT_R16_SSCALED,
   PIPE_FORMAT_R16G16_SSCALED,
   PIPE_FORMAT_R16G16B16_SSCALED,
   PIPE_FORMAT_R16G16B16A16_SSCALED
};

static GLuint ubyte_types_norm[4] = {
   PIPE_FORMAT_R8_UNORM,
   PIPE_FORMAT_R8G8_UNORM,
   PIPE_FORMAT_R8G8B8_UNORM,
   PIPE_FORMAT_R8G8B8A8_UNORM
};

static GLuint ubyte_types_scale[4] = {
   PIPE_FORMAT_R8_USCALED,
   PIPE_FORMAT_R8G8_USCALED,
   PIPE_FORMAT_R8G8B8_USCALED,
   PIPE_FORMAT_R8G8B8A8_USCALED
};

static GLuint byte_types_norm[4] = {
   PIPE_FORMAT_R8_SNORM,
   PIPE_FORMAT_R8G8_SNORM,
   PIPE_FORMAT_R8G8B8_SNORM,
   PIPE_FORMAT_R8G8B8A8_SNORM
};

static GLuint byte_types_scale[4] = {
   PIPE_FORMAT_R8_SSCALED,
   PIPE_FORMAT_R8G8_SSCALED,
   PIPE_FORMAT_R8G8B8_SSCALED,
   PIPE_FORMAT_R8G8B8A8_SSCALED
};


/**
 * Return a PIPE_FORMAT_x for the given GL datatype and size.
 */
static GLuint
pipe_vertex_format(GLenum type, GLuint size, GLboolean normalized)
{
   assert(type >= GL_BYTE);
   assert(type <= GL_DOUBLE);
   assert(size >= 1);
   assert(size <= 4);

   if (normalized) {
      switch (type) {
      case GL_DOUBLE: return double_types[size-1];
      case GL_FLOAT: return float_types[size-1];
      case GL_INT: return int_types_norm[size-1];
      case GL_SHORT: return short_types_norm[size-1];
      case GL_BYTE: return byte_types_norm[size-1];
      case GL_UNSIGNED_INT: return uint_types_norm[size-1];
      case GL_UNSIGNED_SHORT: return ushort_types_norm[size-1];
      case GL_UNSIGNED_BYTE: return ubyte_types_norm[size-1];
      default: assert(0); return 0;
      }      
   }
   else {
      switch (type) {
      case GL_DOUBLE: return double_types[size-1];
      case GL_FLOAT: return float_types[size-1];
      case GL_INT: return int_types_scale[size-1];
      case GL_SHORT: return short_types_scale[size-1];
      case GL_BYTE: return byte_types_scale[size-1];
      case GL_UNSIGNED_INT: return uint_types_scale[size-1];
      case GL_UNSIGNED_SHORT: return ushort_types_scale[size-1];
      case GL_UNSIGNED_BYTE: return ubyte_types_scale[size-1];
      default: assert(0); return 0;
      }      
   }
   return 0; /* silence compiler warning */
}


/*
 * If edge flags are needed, setup an bitvector of flags and call
 * pipe->set_edgeflags().
 * XXX memleak: need to free the returned pointer at some point
 */
static void *
setup_edgeflags(GLcontext *ctx, GLenum primMode, GLint start, GLint count,
                const struct gl_client_array *array)
{
   struct pipe_context *pipe = ctx->st->pipe;

   if ((primMode == GL_TRIANGLES ||
        primMode == GL_QUADS ||
        primMode == GL_POLYGON) &&
       (ctx->Polygon.FrontMode != GL_FILL ||
        ctx->Polygon.BackMode != GL_FILL)) {
      /* need edge flags */
      GLuint i;
      unsigned *vec = (unsigned *) calloc(sizeof(unsigned), (count + 31) / 32);
      struct st_buffer_object *stobj = st_buffer_object(array->BufferObj);
      ubyte *map;

      if (!vec)
         return NULL;

      map = pipe->winsys->buffer_map(pipe->winsys, stobj->buffer,
                                     PIPE_BUFFER_USAGE_CPU_READ);
      map = ADD_POINTERS(map, array->Ptr);

      for (i = 0; i < count; i++) {
         if (*((float *) map))
            vec[i/32] |= 1 << (i % 32);

         map += array->StrideB;
      }

      pipe->winsys->buffer_unmap(pipe->winsys, stobj->buffer);

      pipe->set_edgeflags(pipe, vec);

      return vec;
   }
   else {
      /* edge flags not needed */
      pipe->set_edgeflags(pipe, NULL);
      return NULL;
   }
}



/**
 * This function gets plugged into the VBO module and is called when
 * we have something to render.
 * Basically, translate the information into the format expected by pipe.
 */
void
st_draw_vbo(GLcontext *ctx,
            const struct gl_client_array **arrays,
            const struct _mesa_prim *prims,
            GLuint nr_prims,
            const struct _mesa_index_buffer *ib,
            GLuint min_index,
            GLuint max_index)
{
   struct pipe_context *pipe = ctx->st->pipe;
   struct pipe_winsys *winsys = pipe->winsys;
   const struct st_vertex_program *vp;
   const struct pipe_shader_state *vs;
   struct pipe_vertex_buffer vbuffer[PIPE_MAX_SHADER_INPUTS];
   GLuint attr;
   struct pipe_vertex_element velements[PIPE_MAX_ATTRIBS];

   /* sanity check for pointer arithmetic below */
   assert(sizeof(arrays[0]->Ptr[0]) == 1);

   st_validate_state(ctx->st);

   /* must get these after state validation! */
   vp = ctx->st->vp;
   vs = &ctx->st->vp->state;

   /* loop over TGSI shader inputs to determine vertex buffer
    * and attribute info
    */
   for (attr = 0; attr < vp->num_inputs; attr++) {
      const GLuint mesaAttr = vp->index_to_input[attr];
      struct gl_buffer_object *bufobj = arrays[mesaAttr]->BufferObj;

      if (bufobj && bufobj->Name) {
         /* Attribute data is in a VBO.
          * Recall that for VBOs, the gl_client_array->Ptr field is
          * really an offset from the start of the VBO, not a pointer.
          */
         struct st_buffer_object *stobj = st_buffer_object(bufobj);
         assert(stobj->buffer);

         vbuffer[attr].buffer = NULL;
         pipe_buffer_reference(winsys, &vbuffer[attr].buffer, stobj->buffer);
         vbuffer[attr].buffer_offset = (unsigned) arrays[0]->Ptr;/* in bytes */
         velements[attr].src_offset = arrays[mesaAttr]->Ptr - arrays[0]->Ptr;
         assert(velements[attr].src_offset <= 2048); /* 11-bit field */
      }
      else {
         /* attribute data is in user-space memory, not a VBO */
         uint bytes;
	
         if (!arrays[mesaAttr]->StrideB) {
            bytes = arrays[mesaAttr]->Size
                    * _mesa_sizeof_type(arrays[mesaAttr]->Type);
         } else {
            bytes = arrays[mesaAttr]->StrideB * (max_index + 1);
         }

         /* wrap user data */
         vbuffer[attr].buffer
            = winsys->user_buffer_create(winsys,
                                         (void *) arrays[mesaAttr]->Ptr,
                                         bytes);
         vbuffer[attr].buffer_offset = 0;
         velements[attr].src_offset = 0;
      }

      /* common-case setup */
      vbuffer[attr].pitch = arrays[mesaAttr]->StrideB; /* in bytes */
      vbuffer[attr].max_index = max_index;
      velements[attr].vertex_buffer_index = attr;
      velements[attr].nr_components = arrays[mesaAttr]->Size;
      velements[attr].src_format
         = pipe_vertex_format(arrays[mesaAttr]->Type,
                              arrays[mesaAttr]->Size,
                              arrays[mesaAttr]->Normalized);
      assert(velements[attr].src_format);
   }

   pipe->set_vertex_buffers(pipe, vp->num_inputs, vbuffer);
   pipe->set_vertex_elements(pipe, vp->num_inputs, velements);

   /* do actual drawing */
   if (ib) {
      /* indexed primitive */
      struct gl_buffer_object *bufobj = ib->obj;
      struct pipe_buffer *indexBuf = NULL;
      unsigned indexSize, indexOffset, i;

      switch (ib->type) {
      case GL_UNSIGNED_INT:
         indexSize = 4;
         break;
      case GL_UNSIGNED_SHORT:
         indexSize = 2;
         break;
      case GL_UNSIGNED_BYTE:
         indexSize = 1;
         break;
      default:
         assert(0);
	 return;
      }

      /* get/create the index buffer object */
      if (bufobj && bufobj->Name) {
         /* elements/indexes are in a real VBO */
         struct st_buffer_object *stobj = st_buffer_object(bufobj);
         pipe_buffer_reference(winsys, &indexBuf, stobj->buffer);
         indexOffset = (unsigned) ib->ptr / indexSize;
      }
      else {
         /* element/indicies are in user space memory */
         indexBuf = winsys->user_buffer_create(winsys,
                                               (void *) ib->ptr,
                                               ib->count * indexSize);
         indexOffset = 0;
      }

      /* draw */
      for (i = 0; i < nr_prims; i++) {
         setup_edgeflags(ctx, prims[i].mode,
                         prims[i].start + indexOffset, prims[i].count,
                         arrays[VERT_ATTRIB_EDGEFLAG]);

         pipe->draw_elements(pipe, indexBuf, indexSize,
                             prims[i].mode,
                             prims[i].start + indexOffset, prims[i].count);
      }

      pipe_buffer_reference(winsys, &indexBuf, NULL);
   }
   else {
      /* non-indexed */
      GLuint i;
      for (i = 0; i < nr_prims; i++) {
         setup_edgeflags(ctx, prims[i].mode,
                         prims[i].start, prims[i].count,
                         arrays[VERT_ATTRIB_EDGEFLAG]);

         pipe->draw_arrays(pipe, prims[i].mode, prims[i].start, prims[i].count);
      }
   }

   /* unreference buffers (frees wrapped user-space buffer objects) */
   for (attr = 0; attr < vp->num_inputs; attr++) {
      pipe_buffer_reference(winsys, &vbuffer[attr].buffer, NULL);
      assert(!vbuffer[attr].buffer);
   }
   pipe->set_vertex_buffers(pipe, vp->num_inputs, vbuffer);
}



/**
 * Utility function for drawing simple primitives (such as quads for
 * glClear and glDrawPixels).  Coordinates are in screen space.
 * \param mode  one of PIPE_PRIM_x
 * \param numVertex  number of vertices
 * \param verts  vertex data (all attributes are float[4])
 * \param numAttribs  number of attributes per vertex
 */
void 
st_draw_vertices(GLcontext *ctx, unsigned prim,
                 unsigned numVertex, float *verts,
                 unsigned numAttribs,
                 GLboolean inClipCoords)
{
   const float width = ctx->DrawBuffer->Width;
   const float height = ctx->DrawBuffer->Height;
   const unsigned vertex_bytes = numVertex * numAttribs * 4 * sizeof(float);
   struct pipe_context *pipe = ctx->st->pipe;
   struct pipe_buffer *vbuf;
   struct pipe_vertex_buffer vbuffer;
   struct pipe_vertex_element velements[PIPE_MAX_ATTRIBS];
   unsigned i;

   assert(numAttribs > 0);

   if (!inClipCoords) {
      /* convert to clip coords */
      for (i = 0; i < numVertex; i++) {
         float x = verts[i * numAttribs * 4 + 0];
         float y = verts[i * numAttribs * 4 + 1];
         x = x / width * 2.0 - 1.0;
         y = y / height * 2.0 - 1.0;
         verts[i * numAttribs * 4 + 0] = x;
         verts[i * numAttribs * 4 + 1] = y;
      }
   }

   /* XXX create one-time */
   vbuf = pipe->winsys->buffer_create(pipe->winsys, 32,
                                      PIPE_BUFFER_USAGE_VERTEX, vertex_bytes);
   assert(vbuf);

   memcpy(pipe->winsys->buffer_map(pipe->winsys, vbuf,
                                   PIPE_BUFFER_USAGE_CPU_WRITE),
          verts, vertex_bytes);
   pipe->winsys->buffer_unmap(pipe->winsys, vbuf);

   /* tell pipe about the vertex buffer */
   vbuffer.buffer = vbuf;
   vbuffer.pitch = numAttribs * 4 * sizeof(float);  /* vertex size */
   vbuffer.buffer_offset = 0;
   pipe->set_vertex_buffers(pipe, 1, &vbuffer);

   /* tell pipe about the vertex attributes */
   for (i = 0; i < numAttribs; i++) {
      velements[i].src_offset = i * 4 * sizeof(GLfloat);
      velements[i].vertex_buffer_index = 0;
      velements[i].src_format = PIPE_FORMAT_R32G32B32A32_FLOAT;
      velements[i].nr_components = 4;
   }
   pipe->set_vertex_elements(pipe, numAttribs, velements);

   /* draw */
   pipe->draw_arrays(pipe, prim, 0, numVertex);

   /* XXX: do one-time */
   pipe_buffer_reference(pipe->winsys, &vbuf, NULL);
}


/**
 * Set the (private) draw module's post-transformed vertex format when in
 * GL_SELECT or GL_FEEDBACK mode or for glRasterPos.
 */
static void
set_feedback_vertex_format(GLcontext *ctx)
{
#if 0
   struct st_context *st = ctx->st;
   struct vertex_info vinfo;
   GLuint i;

   memset(&vinfo, 0, sizeof(vinfo));

   if (ctx->RenderMode == GL_SELECT) {
      assert(ctx->RenderMode == GL_SELECT);
      vinfo.num_attribs = 1;
      vinfo.format[0] = FORMAT_4F;
      vinfo.interp_mode[0] = INTERP_LINEAR;
   }
   else {
      /* GL_FEEDBACK, or glRasterPos */
      /* emit all attribs (pos, color, texcoord) as GLfloat[4] */
      vinfo.num_attribs = st->state.vs->cso->state.num_outputs;
      for (i = 0; i < vinfo.num_attribs; i++) {
         vinfo.format[i] = FORMAT_4F;
         vinfo.interp_mode[i] = INTERP_LINEAR;
      }
   }

   draw_set_vertex_info(st->draw, &vinfo);
#endif
}


/**
 * Called by VBO to draw arrays when in selection or feedback mode and
 * to implement glRasterPos.
 * This is very much like the normal draw_vbo() function above.
 * Look at code refactoring some day.
 * Might move this into the failover module some day.
 */
void
st_feedback_draw_vbo(GLcontext *ctx,
                     const struct gl_client_array **arrays,
                     const struct _mesa_prim *prims,
                     GLuint nr_prims,
                     const struct _mesa_index_buffer *ib,
                     GLuint min_index,
                     GLuint max_index)
{
   struct st_context *st = ctx->st;
   struct pipe_context *pipe = st->pipe;
   struct draw_context *draw = st->draw;
   struct pipe_winsys *winsys = pipe->winsys;
   const struct st_vertex_program *vp;
   const struct pipe_shader_state *vs;
   struct pipe_buffer *index_buffer_handle = 0;
   struct pipe_vertex_buffer vbuffers[PIPE_MAX_SHADER_INPUTS];
   struct pipe_vertex_element velements[PIPE_MAX_ATTRIBS];
   GLuint attr, i;
   ubyte *mapped_constants;

   assert(draw);

   st_validate_state(ctx->st);

   /* must get these after state validation! */
   vp = ctx->st->vp;
   vs = &st->vp->state;

   if (!st->vp->draw_shader) {
      st->vp->draw_shader = draw_create_vertex_shader(draw, vs);
   }

   /*
    * Set up the draw module's state.
    *
    * We'd like to do this less frequently, but the normal state-update
    * code sends state updates to the pipe, not to our private draw module.
    */
   assert(draw);
   draw_set_viewport_state(draw, &st->state.viewport);
   draw_set_clip_state(draw, &st->state.clip);
   draw_set_rasterizer_state(draw, &st->state.rasterizer);
   draw_bind_vertex_shader(draw, st->vp->draw_shader);
   set_feedback_vertex_format(ctx);

   /* loop over TGSI shader inputs to determine vertex buffer
    * and attribute info
    */
   for (attr = 0; attr < vp->num_inputs; attr++) {
      const GLuint mesaAttr = vp->index_to_input[attr];
      struct gl_buffer_object *bufobj = arrays[mesaAttr]->BufferObj;
      void *map;

      if (bufobj && bufobj->Name) {
         /* Attribute data is in a VBO.
          * Recall that for VBOs, the gl_client_array->Ptr field is
          * really an offset from the start of the VBO, not a pointer.
          */
         struct st_buffer_object *stobj = st_buffer_object(bufobj);
         assert(stobj->buffer);

         vbuffers[attr].buffer = NULL;
         pipe_buffer_reference(winsys, &vbuffers[attr].buffer, stobj->buffer);
         vbuffers[attr].buffer_offset = (unsigned) arrays[0]->Ptr;/* in bytes */
         velements[attr].src_offset = arrays[mesaAttr]->Ptr - arrays[0]->Ptr;
      }
      else {
         /* attribute data is in user-space memory, not a VBO */
         uint bytes = (arrays[mesaAttr]->Size
                       * _mesa_sizeof_type(arrays[mesaAttr]->Type)
                       * (max_index + 1));

         /* wrap user data */
         vbuffers[attr].buffer
            = winsys->user_buffer_create(winsys,
                                         (void *) arrays[mesaAttr]->Ptr,
                                         bytes);
         vbuffers[attr].buffer_offset = 0;
         velements[attr].src_offset = 0;
      }

      /* common-case setup */
      vbuffers[attr].pitch = arrays[mesaAttr]->StrideB; /* in bytes */
      vbuffers[attr].max_index = max_index;
      velements[attr].vertex_buffer_index = attr;
      velements[attr].nr_components = arrays[mesaAttr]->Size;
      velements[attr].src_format = pipe_vertex_format(arrays[mesaAttr]->Type,
                                               arrays[mesaAttr]->Size,
                                               arrays[mesaAttr]->Normalized);
      assert(velements[attr].src_format);

      /* tell draw about this attribute */
#if 0
      draw_set_vertex_buffer(draw, attr, &vbuffer[attr]);
#endif

      /* map the attrib buffer */
      map = pipe->winsys->buffer_map(pipe->winsys,
                                     vbuffers[attr].buffer,
                                     PIPE_BUFFER_USAGE_CPU_READ);
      draw_set_mapped_vertex_buffer(draw, attr, map);
   }

   draw_set_vertex_buffers(draw, vp->num_inputs, vbuffers);
   draw_set_vertex_elements(draw, vp->num_inputs, velements);

   if (ib) {
      unsigned indexSize;
      struct gl_buffer_object *bufobj = ib->obj;
      struct st_buffer_object *stobj = st_buffer_object(bufobj);
      index_buffer_handle = stobj->buffer;
      void *map;

      switch (ib->type) {
      case GL_UNSIGNED_INT:
         indexSize = 4;
         break;
      case GL_UNSIGNED_SHORT:
         indexSize = 2;
         break;
      default:
         assert(0);
	 return;
      }

      map = pipe->winsys->buffer_map(pipe->winsys,
                                     index_buffer_handle,
                                     PIPE_BUFFER_USAGE_CPU_READ);
      draw_set_mapped_element_buffer(draw, indexSize, map);
   }
   else {
      /* no index/element buffer */
      draw_set_mapped_element_buffer(draw, 0, NULL);
   }


   /* map constant buffers */
   mapped_constants = winsys->buffer_map(winsys,
                               st->state.constants[PIPE_SHADER_VERTEX].buffer,
                               PIPE_BUFFER_USAGE_CPU_READ);
   draw_set_mapped_constant_buffer(st->draw, mapped_constants);


   /* draw here */
   for (i = 0; i < nr_prims; i++) {
      draw_arrays(draw, prims[i].mode, prims[i].start, prims[i].count);
   }


   /* unmap constant buffers */
   winsys->buffer_unmap(winsys, st->state.constants[PIPE_SHADER_VERTEX].buffer);

   /*
    * unmap vertex/index buffers
    */
   for (i = 0; i < PIPE_MAX_ATTRIBS; i++) {
      if (draw->pt.vertex_buffer[i].buffer) {
         pipe->winsys->buffer_unmap(pipe->winsys,
                                    draw->pt.vertex_buffer[i].buffer);
         pipe_buffer_reference(winsys, &draw->pt.vertex_buffer[i].buffer, NULL);
         draw_set_mapped_vertex_buffer(draw, i, NULL);
      }
   }
   if (ib) {
      pipe->winsys->buffer_unmap(pipe->winsys, index_buffer_handle);
      draw_set_mapped_element_buffer(draw, 0, NULL);
   }
}



void st_init_draw( struct st_context *st )
{
   GLcontext *ctx = st->ctx;

   vbo_set_draw_func(ctx, st_draw_vbo);
}


void st_destroy_draw( struct st_context *st )
{
}