2 * $Id: texcache.c,v 1.1 2006-03-13 12:39:07 nkeynes Exp $
4 * Texture cache. Responsible for maintaining a working set of OpenGL
8 * Copyright (c) 2005 Nathan Keynes.
10 * This program is free software; you can redistribute it and/or modify
11 * it under the terms of the GNU General Public License as published by
12 * the Free Software Foundation; either version 2 of the License, or
13 * (at your option) any later version.
15 * This program is distributed in the hope that it will be useful,
16 * but WITHOUT ANY WARRANTY; without even the implied warranty of
17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
18 * GNU General Public License for more details.
22 #include "pvr2/pvr2.h"
24 /** Specifies the maximum number of OpenGL
25 * textures we're willing to have open at a time. If more are
26 * needed, textures will be evicted in LRU order.
28 #define MAX_TEXTURES 64
34 * find entry by texture_addr
36 * move entry to tail of lru list
40 typedef signed short texcache_entry_index;
41 #define EMPTY_ENTRY -1
43 static texcache_entry_index texcache_free_ptr;
44 static GLuint texcache_free_list[MAX_TEXTURES];
46 typedef struct texcache_entry {
47 uint32_t texture_addr;
48 int width, height, mode;
50 texcache_entry_index next;
54 static uint8_t texcache_page_lookup[PVR2_RAM_PAGES];
55 static uint32_t texcache_active_ptr;
56 static uint32_t texcache_ref_counter;
57 static struct texcache_entry texcache_active_list[MAX_TEXTURES];
60 * Initialize the texture cache. Note that the GL context must have been
61 * initialized before calling this function.
66 GLuint texids[MAX_TEXTURES];
67 glGenTextures( MAX_TEXTURES, texids );
68 for( i=0; i<PVR2_RAM_PAGES; i++ ) {
69 texcache_page_lookup[i] = EMPTY_ENTRY;
71 for( i=0; i<MAX_TEXTURES; i++ ) {
72 texcache_active_list[i].texture_id = texids[i];
73 texcache_free_list[i] = i;
75 texcache_free_ptr = 0;
76 texcache_ref_counter = 0;
80 * Flush all textures from the cache, returning them to the free list.
82 void texcache_flush( )
85 /* clear structures */
86 for( i=0; i<PVR2_RAM_PAGES; i++ ) {
87 texcache_page_lookup[i] = EMPTY_ENTRY;
89 for( i=0; i<MAX_TEXTURES; i++ ) {
90 texcache_free_list[i] = i;
92 texcache_free_ptr = 0;
93 texcache_ref_counter = 0;
97 * Flush all textures and delete. The cache will be non-functional until
98 * the next call to texcache_init(). This would typically be done if
99 * switching GL targets.
101 void texcache_shutdown( )
103 GLuint texids[MAX_TEXTURES];
107 for( i=0; i<MAX_TEXTURES; i++ ) {
108 texids[i] = texcache_active_list[i].texture_id;
110 glDeleteTextures( MAX_TEXTURES, texids );
114 * Evict all textures contained in the page identified by a texture address.
116 void texcache_invalidate_page( uint32_t texture_addr ) {
117 uint32_t texture_page = texture_addr >> 12;
118 texcache_entry_index idx = texcache_page_lookup[texture_page];
119 if( idx == EMPTY_ENTRY )
121 assert( texcache_free_ptr > 0 );
123 texcache_entry_t entry = &texcache_active_list[idx];
126 texcache_free_list[texcache_free_ptr] = idx;
128 entry->next = EMPTY_ENTRY;
129 } while( idx != EMPTY_ENTRY );
130 texcache_page_lookup[texture_page] = EMPTY_ENTRY;
134 * Evict a single texture from the cache.
135 * @return the slot of the evicted texture.
137 static texcache_entry_index texcache_evict( void )
139 /* Full table scan - take over the entry with the lowest lru value */
140 texcache_entry_index slot = 0;
141 int lru_value = texcache_active_list[0].lru_count;
143 for( i=1; i<MAX_TEXTURES; i++ ) {
144 /* FIXME: account for rollover */
145 if( texcache_active_list[i].lru_count < lru_value ) {
147 lru_value = texcache_active_list[i].lru_count;
151 /* Remove the selected slot from the lookup table */
152 uint32_t evict_page = texcache_active_list[slot].texture_addr;
153 texcache_entry_index replace_next = texcache_active_list[slot].next;
154 texcache_active_list[slot].next = EMPTY_ENTRY; /* Just for safety */
155 if( texcache_page_lookup[evict_page] == slot ) {
156 texcache_page_lookup[evict_page] = replace_next;
158 texcache_entry_index idx = texcache_page_lookup[evict_page];
159 texcache_entry_index next;
161 next = texcache_active_list[idx].next;
163 texcache_active_list[idx].next = replace_next;
167 } while( next != EMPTY_ENTRY );
173 * Load texture data from the given address and parameters into the currently
174 * bound OpenGL texture.
176 static texcache_load_texture( uint32_t texture_addr, int width, int height,
178 uint32_t bytes = width * height;
180 GLint intFormat, format, type;
181 switch( mode & PVR2_TEX_FORMAT_MASK ) {
182 case PVR2_TEX_FORMAT_ARGB1555:
184 intFormat = GL_RGB5_A1;
186 type = GL_UNSIGNED_SHORT_5_5_5_1;
188 case PVR2_TEX_FORMAT_RGB565:
192 type = GL_UNSIGNED_SHORT_5_6_5;
194 case PVR2_TEX_FORMAT_ARGB4444:
196 intFormat = GL_RGBA4;
198 type = GL_UNSIGNED_SHORT_4_4_4_4;
200 case PVR2_TEX_FORMAT_YUV422:
201 ERROR( "YUV textures not supported" );
203 case PVR2_TEX_FORMAT_BUMPMAP:
204 ERROR( "Bumpmap not supported" );
206 case PVR2_TEX_FORMAT_IDX4:
209 intFormat = GL_INTENSITY4;
210 format = GL_COLOR_INDEX;
211 type = GL_UNSIGNED_BYTE;
214 case PVR2_TEX_FORMAT_IDX8:
215 intFormat = GL_INTENSITY8;
216 format = GL_COLOR_INDEX;
217 type = GL_UNSIGNED_BYTE;
222 unsigned char data[bytes];
223 /* load data from image, detwiddling/uncompressing as required */
224 if( PVR2_TEX_IS_COMPRESSED(mode) ) {
225 ERROR( "VQ Compression not supported" );
227 pvr2_vram64_read( &data, texture_addr, bytes );
228 if( PVR2_TEX_IS_TWIDDLED(mode) ) {
233 glTexImage2D( GL_TEXTURE_2D, 0, intFormat, width, height, 0, format, type,
238 * Return a texture ID for the texture specified at the supplied address
239 * and given parameters (the same sequence of bytes could in theory have
240 * multiple interpretations). We use the texture address as the primary
241 * index, but allow for multiple instances at each address. The texture
242 * will be bound to the GL_TEXTURE_2D target before being returned.
244 * If the texture has already been bound, return the ID to which it was
245 * bound. Otherwise obtain an unused texture ID and set it up appropriately.
247 GLuint texcache_get_texture( uint32_t texture_addr, int width, int height,
250 uint32_t texture_page = texture_addr >> 12;
251 texcache_entry_index idx = texcache_page_lookup[texture_page];
252 while( idx != EMPTY_ENTRY ) {
253 texcache_entry_t entry = &texcache_active_list[idx];
254 if( entry->texture_addr == texture_addr &&
255 entry->mode == mode &&
256 entry->width == width &&
257 entry->height == height ) {
258 entry->lru_count = texcache_ref_counter++;
259 glBindTexture( GL_TEXTURE_2D, entry->texture_id );
260 return entry->texture_id;
265 /* Not found - check the free list */
268 if( texcache_free_ptr < MAX_TEXTURES ) {
269 slot = texcache_free_list[texcache_free_ptr++];
271 slot = texcache_evict();
274 /* Construct new entry */
275 texcache_active_list[slot].texture_addr = texture_addr;
276 texcache_active_list[slot].width = width;
277 texcache_active_list[slot].height = height;
278 texcache_active_list[slot].mode = mode;
279 texcache_active_list[slot].lru_count = texcache_ref_counter++;
281 /* Add entry to the lookup table */
282 texcache_active_list[slot].next = texcache_page_lookup[texture_page];
283 texcache_page_lookup[texture_page] = slot;
285 /* Construct the GL texture */
286 GLuint texid = texcache_free_list[texcache_free_ptr++];
287 glBindTexture( GL_TEXTURE_2D, texid );
288 texcache_load_texture( texture_addr, width, height, mode );
290 return texcache_active_list[slot].texture_id;
.