1
2/*
3 * Mesa 3-D graphics library
4 *
5 * Copyright (C) 1999-2006  Brian Paul   All Rights Reserved.
6 *
7 * Permission is hereby granted, free of charge, to any person obtaining a
8 * copy of this software and associated documentation files (the "Software"),
9 * to deal in the Software without restriction, including without limitation
10 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
11 * and/or sell copies of the Software, and to permit persons to whom the
12 * Software is furnished to do so, subject to the following conditions:
13 *
14 * The above copyright notice and this permission notice shall be included
15 * in all copies or substantial portions of the Software.
16 *
17 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
18 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
19 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
20 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
21 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
22 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
23 * OTHER DEALINGS IN THE SOFTWARE.
24 *
25 * Authors:
26 *    Keith Whitwell <keithw@vmware.com>
27 */
28
29/* Helper for drivers which find themselves rendering a range of
30 * indices starting somewhere above zero.  Typically the application
31 * is issuing multiple DrawArrays() or DrawElements() to draw
32 * successive primitives layed out linearly in the vertex arrays.
33 * Unless the vertex arrays are all in a VBO, the OpenGL semantics
34 * imply that we need to re-upload the vertex data on each draw call.
35 * In that case, we want to avoid starting the upload at zero, as it
36 * will mean every draw call uploads an increasing amount of not-used
37 * vertex data.  Worse - in the software tnl module, all those
38 * vertices will be transformed and lit.
39 *
40 * If we just upload the new data, however, the indices will be
41 * incorrect as we tend to upload each set of vertex data to a new
42 * region.
43 *
44 * This file provides a helper to adjust the arrays, primitives and
45 * indices of a draw call so that it can be re-issued with a min_index
46 * of zero.
47 */
48
49#include <stdio.h>
50#include "main/bufferobj.h"
51#include "main/errors.h"
52#include "main/glheader.h"
53#include "main/imports.h"
54#include "main/mtypes.h"
55#include "vbo/vbo.h"
56
57#include "t_rebase.h"
58
59
60#define REBASE(TYPE) 						\
61static void *rebase_##TYPE( const void *ptr,			\
62			  GLuint count, 			\
63			  TYPE min_index )			\
64{								\
65   GLuint i;							\
66   const TYPE *in = (TYPE *)ptr;				\
67   TYPE *tmp_indices = malloc(count * sizeof(TYPE));		\
68								\
69   if (tmp_indices == NULL) {                                   \
70      _mesa_error_no_memory(__func__);                          \
71      return NULL;                                              \
72   }                                                            \
73								\
74   for (i = 0; i < count; i++)  				\
75      tmp_indices[i] = in[i] - min_index;			\
76								\
77   return (void *)tmp_indices;					\
78}
79
80
81REBASE(GLuint)
82REBASE(GLushort)
83REBASE(GLubyte)
84
85
86
87/* Adjust primitives, indices and vertex definitions so that min_index
88 * becomes zero. There are lots of reasons for wanting to do this, eg:
89 *
90 * Software tnl:
91 *    - any time min_index != 0, otherwise unused vertices lower than
92 *      min_index will be transformed.
93 *
94 * Hardware tnl:
95 *    - if ib != NULL and min_index != 0, otherwise vertices lower than
96 *      min_index will be uploaded.  Requires adjusting index values.
97 *
98 *    - if ib == NULL and min_index != 0, just for convenience so this doesn't
99 *      have to be handled within the driver.
100 *
101 * Hardware tnl with VBO support:
102 *    - as above, but only when vertices are not (all?) in VBO's.
103 *    - can't save time by trying to upload half a vbo - typically it is
104 *      all or nothing.
105 */
106void t_rebase_prims( struct gl_context *ctx,
107                     const struct tnl_vertex_array *arrays,
108                     const struct _mesa_prim *prim,
109                     GLuint nr_prims,
110                     const struct _mesa_index_buffer *ib,
111                     GLuint min_index,
112                     GLuint max_index,
113                     tnl_draw_func draw )
114{
115   struct gl_array_attributes tmp_attribs[VERT_ATTRIB_MAX];
116   struct tnl_vertex_array tmp_arrays[VERT_ATTRIB_MAX];
117
118   struct _mesa_index_buffer tmp_ib;
119   struct _mesa_prim *tmp_prims = NULL;
120   void *tmp_indices = NULL;
121   GLuint i;
122
123   assert(min_index != 0);
124
125   if (0)
126      printf("%s %d..%d\n", __func__, min_index, max_index);
127
128
129   /* XXX this path is disabled for now.
130    * There's rendering corruption in some apps when it's enabled.
131    */
132   if (0 && ib && ctx->Extensions.ARB_draw_elements_base_vertex) {
133      /* If we can just tell the hardware or the TNL to interpret our
134       * indices with a different base, do so.
135       */
136      tmp_prims = malloc(sizeof(*prim) * nr_prims);
137
138      if (tmp_prims == NULL) {
139         _mesa_error_no_memory(__func__);
140         return;
141      }
142
143      for (i = 0; i < nr_prims; i++) {
144	 tmp_prims[i] = prim[i];
145	 tmp_prims[i].basevertex -= min_index;
146      }
147
148      prim = tmp_prims;
149   } else if (ib) {
150      /* Unfortunately need to adjust each index individually.
151       */
152      GLboolean map_ib = ib->obj->Name &&
153                         !ib->obj->Mappings[MAP_INTERNAL].Pointer;
154      void *ptr;
155
156      if (map_ib)
157	 ctx->Driver.MapBufferRange(ctx, 0, ib->obj->Size, GL_MAP_READ_BIT,
158				    ib->obj, MAP_INTERNAL);
159
160
161      ptr = ADD_POINTERS(ib->obj->Mappings[MAP_INTERNAL].Pointer, ib->ptr);
162
163      /* Some users might prefer it if we translated elements to
164       * GLuints here.  Others wouldn't...
165       */
166      switch (ib->index_size) {
167      case 4:
168	 tmp_indices = rebase_GLuint( ptr, ib->count, min_index );
169	 break;
170      case 2:
171	 tmp_indices = rebase_GLushort( ptr, ib->count, min_index );
172	 break;
173      case 1:
174	 tmp_indices = rebase_GLubyte( ptr, ib->count, min_index );
175	 break;
176      }
177
178      if (map_ib)
179	 ctx->Driver.UnmapBuffer(ctx, ib->obj, MAP_INTERNAL);
180
181      if (tmp_indices == NULL) {
182         return;
183      }
184
185      tmp_ib.obj = ctx->Shared->NullBufferObj;
186      tmp_ib.ptr = tmp_indices;
187      tmp_ib.count = ib->count;
188      tmp_ib.index_size = ib->index_size;
189
190      ib = &tmp_ib;
191   }
192   else {
193      /* Otherwise the primitives need adjustment.
194       */
195      tmp_prims = malloc(sizeof(*prim) * nr_prims);
196
197      if (tmp_prims == NULL) {
198         _mesa_error_no_memory(__func__);
199         return;
200      }
201
202      for (i = 0; i < nr_prims; i++) {
203	 /* If this fails, it could indicate an application error:
204	  */
205	 assert(prim[i].start >= min_index);
206
207	 tmp_prims[i] = prim[i];
208	 tmp_prims[i].start -= min_index;
209      }
210
211      prim = tmp_prims;
212   }
213
214   /* Just need to adjust the pointer values on each incoming array.
215    * This works for VBO and non-vbo rendering and shouldn't pesimize
216    * VBO-based upload schemes.  However this may still not be a fast
217    * path for hardware tnl for VBO based rendering as most machines
218    * will be happier if you just specify a starting vertex value in
219    * each primitive.
220    *
221    * For drivers with hardware tnl, you only want to do this if you
222    * are forced to, eg non-VBO indexed rendering with start != 0.
223    */
224   for (i = 0; i < VERT_ATTRIB_MAX; i++) {
225      tmp_attribs[i] = *(arrays[i].VertexAttrib);
226      tmp_arrays[i].BufferBinding = arrays[i].BufferBinding;
227      tmp_arrays[i].VertexAttrib = &tmp_attribs[i];
228      if (_mesa_is_bufferobj(arrays[i].BufferBinding->BufferObj))
229         tmp_attribs[i].RelativeOffset +=
230            min_index * arrays[i].BufferBinding->Stride;
231      else
232         tmp_attribs[i].Ptr += min_index * arrays[i].BufferBinding->Stride;
233   }
234
235   /* Re-issue the draw call.
236    */
237   draw( ctx,
238         tmp_arrays,
239	 prim,
240	 nr_prims,
241	 ib,
242	 GL_TRUE,
243	 0,
244	 max_index - min_index,
245	 NULL, 0, NULL );
246
247   free(tmp_indices);
248
249   free(tmp_prims);
250}
251
252
253
254