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      1 /*
      2  * Copyright 2009 Marek Olk <maraeo (at) gmail.com>
      3  *
      4  * Permission is hereby granted, free of charge, to any person obtaining a
      5  * copy of this software and associated documentation files (the "Software"),
      6  * to deal in the Software without restriction, including without limitation
      7  * on the rights to use, copy, modify, merge, publish, distribute, sub
      8  * license, and/or sell copies of the Software, and to permit persons to whom
      9  * the Software is furnished to do so, subject to the following conditions:
     10  *
     11  * The above copyright notice and this permission notice (including the next
     12  * paragraph) shall be included in all copies or substantial portions of the
     13  * Software.
     14  *
     15  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
     16  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
     17  * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
     18  * THE AUTHOR(S) AND/OR THEIR SUPPLIERS BE LIABLE FOR ANY CLAIM,
     19  * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
     20  * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
     21  * USE OR OTHER DEALINGS IN THE SOFTWARE. */
     22 
     23 #include "r300_context.h"
     24 #include "r300_emit.h"
     25 #include "r300_texture.h"
     26 
     27 #include "util/u_format.h"
     28 #include "util/u_pack_color.h"
     29 #include "util/u_surface.h"
     30 
     31 enum r300_blitter_op /* bitmask */
     32 {
     33     R300_STOP_QUERY         = 1,
     34     R300_SAVE_TEXTURES      = 2,
     35     R300_SAVE_FRAMEBUFFER   = 4,
     36     R300_IGNORE_RENDER_COND = 8,
     37 
     38     R300_CLEAR         = R300_STOP_QUERY,
     39 
     40     R300_CLEAR_SURFACE = R300_STOP_QUERY | R300_SAVE_FRAMEBUFFER,
     41 
     42     R300_COPY          = R300_STOP_QUERY | R300_SAVE_FRAMEBUFFER |
     43                          R300_SAVE_TEXTURES | R300_IGNORE_RENDER_COND,
     44 
     45     R300_DECOMPRESS    = R300_STOP_QUERY | R300_IGNORE_RENDER_COND,
     46 };
     47 
     48 static void r300_blitter_begin(struct r300_context* r300, enum r300_blitter_op op)
     49 {
     50     if ((op & R300_STOP_QUERY) && r300->query_current) {
     51         r300->blitter_saved_query = r300->query_current;
     52         r300_stop_query(r300);
     53     }
     54 
     55     /* Yeah we have to save all those states to ensure the blitter operation
     56      * is really transparent. The states will be restored by the blitter once
     57      * copying is done. */
     58     util_blitter_save_blend(r300->blitter, r300->blend_state.state);
     59     util_blitter_save_depth_stencil_alpha(r300->blitter, r300->dsa_state.state);
     60     util_blitter_save_stencil_ref(r300->blitter, &(r300->stencil_ref));
     61     util_blitter_save_rasterizer(r300->blitter, r300->rs_state.state);
     62     util_blitter_save_fragment_shader(r300->blitter, r300->fs.state);
     63     util_blitter_save_vertex_shader(r300->blitter, r300->vs_state.state);
     64     util_blitter_save_viewport(r300->blitter, &r300->viewport);
     65     util_blitter_save_vertex_buffers(r300->blitter, r300->nr_vertex_buffers,
     66                                      r300->vertex_buffer);
     67     util_blitter_save_vertex_elements(r300->blitter, r300->velems);
     68 
     69     if (op & R300_SAVE_FRAMEBUFFER) {
     70         util_blitter_save_framebuffer(r300->blitter, r300->fb_state.state);
     71     }
     72 
     73     if (op & R300_SAVE_TEXTURES) {
     74         struct r300_textures_state* state =
     75             (struct r300_textures_state*)r300->textures_state.state;
     76 
     77         util_blitter_save_fragment_sampler_states(
     78             r300->blitter, state->sampler_state_count,
     79             (void**)state->sampler_states);
     80 
     81         util_blitter_save_fragment_sampler_views(
     82             r300->blitter, state->sampler_view_count,
     83             (struct pipe_sampler_view**)state->sampler_views);
     84     }
     85 
     86     if (op & R300_IGNORE_RENDER_COND) {
     87         /* Save the flag. */
     88         r300->blitter_saved_skip_rendering = r300->skip_rendering+1;
     89         r300->skip_rendering = FALSE;
     90     } else {
     91         r300->blitter_saved_skip_rendering = 0;
     92     }
     93 }
     94 
     95 static void r300_blitter_end(struct r300_context *r300)
     96 {
     97     if (r300->blitter_saved_query) {
     98         r300_resume_query(r300, r300->blitter_saved_query);
     99         r300->blitter_saved_query = NULL;
    100     }
    101 
    102     if (r300->blitter_saved_skip_rendering) {
    103         /* Restore the flag. */
    104         r300->skip_rendering = r300->blitter_saved_skip_rendering-1;
    105     }
    106 }
    107 
    108 static uint32_t r300_depth_clear_cb_value(enum pipe_format format,
    109                                           const float* rgba)
    110 {
    111     union util_color uc;
    112     util_pack_color(rgba, format, &uc);
    113 
    114     if (util_format_get_blocksizebits(format) == 32)
    115         return uc.ui;
    116     else
    117         return uc.us | (uc.us << 16);
    118 }
    119 
    120 static boolean r300_cbzb_clear_allowed(struct r300_context *r300,
    121                                        unsigned clear_buffers)
    122 {
    123     struct pipe_framebuffer_state *fb =
    124         (struct pipe_framebuffer_state*)r300->fb_state.state;
    125 
    126     /* Only color clear allowed, and only one colorbuffer. */
    127     if (clear_buffers != PIPE_CLEAR_COLOR || fb->nr_cbufs != 1)
    128         return FALSE;
    129 
    130     return r300_surface(fb->cbufs[0])->cbzb_allowed;
    131 }
    132 
    133 static boolean r300_fast_zclear_allowed(struct r300_context *r300)
    134 {
    135     struct pipe_framebuffer_state *fb =
    136         (struct pipe_framebuffer_state*)r300->fb_state.state;
    137 
    138     return r300_resource(fb->zsbuf->texture)->tex.zmask_dwords[fb->zsbuf->u.tex.level] != 0;
    139 }
    140 
    141 static boolean r300_hiz_clear_allowed(struct r300_context *r300)
    142 {
    143     struct pipe_framebuffer_state *fb =
    144         (struct pipe_framebuffer_state*)r300->fb_state.state;
    145 
    146     return r300_resource(fb->zsbuf->texture)->tex.hiz_dwords[fb->zsbuf->u.tex.level] != 0;
    147 }
    148 
    149 static uint32_t r300_depth_clear_value(enum pipe_format format,
    150                                        double depth, unsigned stencil)
    151 {
    152     switch (format) {
    153         case PIPE_FORMAT_Z16_UNORM:
    154         case PIPE_FORMAT_X8Z24_UNORM:
    155             return util_pack_z(format, depth);
    156 
    157         case PIPE_FORMAT_S8_UINT_Z24_UNORM:
    158             return util_pack_z_stencil(format, depth, stencil);
    159 
    160         default:
    161             assert(0);
    162             return 0;
    163     }
    164 }
    165 
    166 static uint32_t r300_hiz_clear_value(double depth)
    167 {
    168     uint32_t r = (uint32_t)(CLAMP(depth, 0, 1) * 255.5);
    169     assert(r <= 255);
    170     return r | (r << 8) | (r << 16) | (r << 24);
    171 }
    172 
    173 /* Clear currently bound buffers. */
    174 static void r300_clear(struct pipe_context* pipe,
    175                        unsigned buffers,
    176                        const union pipe_color_union *color,
    177                        double depth,
    178                        unsigned stencil)
    179 {
    180     /* My notes about Zbuffer compression:
    181      *
    182      * 1) The zbuffer must be micro-tiled and whole microtiles must be
    183      *    written if compression is enabled. If microtiling is disabled,
    184      *    it locks up.
    185      *
    186      * 2) There is ZMASK RAM which contains a compressed zbuffer.
    187      *    Each dword of the Z Mask contains compression information
    188      *    for 16 4x4 pixel tiles, that is 2 bits for each tile.
    189      *    On chips with 2 Z pipes, every other dword maps to a different
    190      *    pipe. On newer chipsets, there is a new compression mode
    191      *    with 8x8 pixel tiles per 2 bits.
    192      *
    193      * 3) The FASTFILL bit has nothing to do with filling. It only tells hw
    194      *    it should look in the ZMASK RAM first before fetching from a real
    195      *    zbuffer.
    196      *
    197      * 4) If a pixel is in a cleared state, ZB_DEPTHCLEARVALUE is returned
    198      *    during zbuffer reads instead of the value that is actually stored
    199      *    in the zbuffer memory. A pixel is in a cleared state when its ZMASK
    200      *    is equal to 0. Therefore, if you clear ZMASK with zeros, you may
    201      *    leave the zbuffer memory uninitialized, but then you must enable
    202      *    compression, so that the ZMASK RAM is actually used.
    203      *
    204      * 5) Each 4x4 (or 8x8) tile is automatically decompressed and recompressed
    205      *    during zbuffer updates. A special decompressing operation should be
    206      *    used to fully decompress a zbuffer, which basically just stores all
    207      *    compressed tiles in ZMASK to the zbuffer memory.
    208      *
    209      * 6) For a 16-bit zbuffer, compression causes a hung with one or
    210      *    two samples and should not be used.
    211      *
    212      * 7) FORCE_COMPRESSED_STENCIL_VALUE should be enabled for stencil clears
    213      *    to avoid needless decompression.
    214      *
    215      * 8) Fastfill must not be used if reading of compressed Z data is disabled
    216      *    and writing of compressed Z data is enabled (RD/WR_COMP_ENABLE),
    217      *    i.e. it cannot be used to compress the zbuffer.
    218      *
    219      * 9) ZB_CB_CLEAR does not interact with zbuffer compression in any way.
    220      *
    221      * - Marek
    222      */
    223 
    224     struct r300_context* r300 = r300_context(pipe);
    225     struct pipe_framebuffer_state *fb =
    226         (struct pipe_framebuffer_state*)r300->fb_state.state;
    227     struct r300_hyperz_state *hyperz =
    228         (struct r300_hyperz_state*)r300->hyperz_state.state;
    229     uint32_t width = fb->width;
    230     uint32_t height = fb->height;
    231     uint32_t hyperz_dcv = hyperz->zb_depthclearvalue;
    232 
    233     /* Enable fast Z clear.
    234      * The zbuffer must be in micro-tiled mode, otherwise it locks up. */
    235     if (buffers & PIPE_CLEAR_DEPTHSTENCIL) {
    236         boolean zmask_clear, hiz_clear;
    237 
    238         zmask_clear = r300_fast_zclear_allowed(r300);
    239         hiz_clear = r300_hiz_clear_allowed(r300);
    240 
    241         /* If we need Hyper-Z. */
    242         if (zmask_clear || hiz_clear) {
    243             r300->num_z_clears++;
    244 
    245             /* Try to obtain the access to Hyper-Z buffers if we don't have one. */
    246             if (!r300->hyperz_enabled) {
    247                 r300->hyperz_enabled =
    248                     r300->rws->cs_request_feature(r300->cs,
    249                                                 RADEON_FID_R300_HYPERZ_ACCESS,
    250                                                 TRUE);
    251                 if (r300->hyperz_enabled) {
    252                    /* Need to emit HyperZ buffer regs for the first time. */
    253                    r300_mark_fb_state_dirty(r300, R300_CHANGED_HYPERZ_FLAG);
    254                 }
    255             }
    256 
    257             /* Setup Hyper-Z clears. */
    258             if (r300->hyperz_enabled) {
    259                 DBG(r300, DBG_HYPERZ, "r300: Clear memory: %s%s\n",
    260                     zmask_clear ? "ZMASK " : "", hiz_clear ? "HIZ" : "");
    261 
    262                 if (zmask_clear) {
    263                     hyperz_dcv = hyperz->zb_depthclearvalue =
    264                         r300_depth_clear_value(fb->zsbuf->format, depth, stencil);
    265 
    266                     r300_mark_atom_dirty(r300, &r300->zmask_clear);
    267                     buffers &= ~PIPE_CLEAR_DEPTHSTENCIL;
    268                 }
    269 
    270                 if (hiz_clear) {
    271                     r300->hiz_clear_value = r300_hiz_clear_value(depth);
    272                     r300_mark_atom_dirty(r300, &r300->hiz_clear);
    273                 }
    274             }
    275         }
    276     }
    277 
    278     /* Enable CBZB clear. */
    279     if (r300_cbzb_clear_allowed(r300, buffers)) {
    280         struct r300_surface *surf = r300_surface(fb->cbufs[0]);
    281 
    282         hyperz->zb_depthclearvalue =
    283                 r300_depth_clear_cb_value(surf->base.format, color->f);
    284 
    285         width = surf->cbzb_width;
    286         height = surf->cbzb_height;
    287 
    288         r300->cbzb_clear = TRUE;
    289         r300_mark_fb_state_dirty(r300, R300_CHANGED_HYPERZ_FLAG);
    290     }
    291 
    292     /* Clear. */
    293     if (buffers) {
    294         enum pipe_format cformat = fb->nr_cbufs ? fb->cbufs[0]->format : PIPE_FORMAT_NONE;
    295         /* Clear using the blitter. */
    296         r300_blitter_begin(r300, R300_CLEAR);
    297         util_blitter_clear(r300->blitter,
    298                            width,
    299                            height,
    300                            fb->nr_cbufs,
    301                            buffers, cformat, color, depth, stencil);
    302         r300_blitter_end(r300);
    303     } else if (r300->zmask_clear.dirty || r300->hiz_clear.dirty) {
    304         /* Just clear zmask and hiz now, this does not use the standard draw
    305          * procedure. */
    306         /* Calculate zmask_clear and hiz_clear atom sizes. */
    307         unsigned dwords =
    308             (r300->zmask_clear.dirty ? r300->zmask_clear.size : 0) +
    309             (r300->hiz_clear.dirty ? r300->hiz_clear.size : 0) +
    310             r300_get_num_cs_end_dwords(r300);
    311 
    312         /* Reserve CS space. */
    313         if (dwords > (RADEON_MAX_CMDBUF_DWORDS - r300->cs->cdw)) {
    314             r300_flush(&r300->context, RADEON_FLUSH_ASYNC, NULL);
    315         }
    316 
    317         /* Emit clear packets. */
    318         if (r300->zmask_clear.dirty) {
    319             r300_emit_zmask_clear(r300, r300->zmask_clear.size,
    320                                   r300->zmask_clear.state);
    321             r300->zmask_clear.dirty = FALSE;
    322         }
    323         if (r300->hiz_clear.dirty) {
    324             r300_emit_hiz_clear(r300, r300->hiz_clear.size,
    325                                 r300->hiz_clear.state);
    326             r300->hiz_clear.dirty = FALSE;
    327         }
    328     } else {
    329         assert(0);
    330     }
    331 
    332     /* Disable CBZB clear. */
    333     if (r300->cbzb_clear) {
    334         r300->cbzb_clear = FALSE;
    335         hyperz->zb_depthclearvalue = hyperz_dcv;
    336         r300_mark_fb_state_dirty(r300, R300_CHANGED_HYPERZ_FLAG);
    337     }
    338 
    339     /* Enable fastfill and/or hiz.
    340      *
    341      * If we cleared zmask/hiz, it's in use now. The Hyper-Z state update
    342      * looks if zmask/hiz is in use and programs hardware accordingly. */
    343     if (r300->zmask_in_use || r300->hiz_in_use) {
    344         r300_mark_atom_dirty(r300, &r300->hyperz_state);
    345     }
    346 }
    347 
    348 /* Clear a region of a color surface to a constant value. */
    349 static void r300_clear_render_target(struct pipe_context *pipe,
    350                                      struct pipe_surface *dst,
    351                                      const union pipe_color_union *color,
    352                                      unsigned dstx, unsigned dsty,
    353                                      unsigned width, unsigned height)
    354 {
    355     struct r300_context *r300 = r300_context(pipe);
    356 
    357     r300_blitter_begin(r300, R300_CLEAR_SURFACE);
    358     util_blitter_clear_render_target(r300->blitter, dst, color,
    359                                      dstx, dsty, width, height);
    360     r300_blitter_end(r300);
    361 }
    362 
    363 /* Clear a region of a depth stencil surface. */
    364 static void r300_clear_depth_stencil(struct pipe_context *pipe,
    365                                      struct pipe_surface *dst,
    366                                      unsigned clear_flags,
    367                                      double depth,
    368                                      unsigned stencil,
    369                                      unsigned dstx, unsigned dsty,
    370                                      unsigned width, unsigned height)
    371 {
    372     struct r300_context *r300 = r300_context(pipe);
    373     struct pipe_framebuffer_state *fb =
    374         (struct pipe_framebuffer_state*)r300->fb_state.state;
    375 
    376     if (r300->zmask_in_use && !r300->locked_zbuffer) {
    377         if (fb->zsbuf->texture == dst->texture) {
    378             r300_decompress_zmask(r300);
    379         }
    380     }
    381 
    382     /* XXX Do not decompress ZMask of the currently-set zbuffer. */
    383     r300_blitter_begin(r300, R300_CLEAR_SURFACE);
    384     util_blitter_clear_depth_stencil(r300->blitter, dst, clear_flags, depth, stencil,
    385                                      dstx, dsty, width, height);
    386     r300_blitter_end(r300);
    387 }
    388 
    389 void r300_decompress_zmask(struct r300_context *r300)
    390 {
    391     struct pipe_framebuffer_state *fb =
    392         (struct pipe_framebuffer_state*)r300->fb_state.state;
    393 
    394     if (!r300->zmask_in_use || r300->locked_zbuffer)
    395         return;
    396 
    397     r300->zmask_decompress = TRUE;
    398     r300_mark_atom_dirty(r300, &r300->hyperz_state);
    399 
    400     r300_blitter_begin(r300, R300_DECOMPRESS);
    401     util_blitter_custom_clear_depth(r300->blitter, fb->width, fb->height, 0,
    402                                     r300->dsa_decompress_zmask);
    403     r300_blitter_end(r300);
    404 
    405     r300->zmask_decompress = FALSE;
    406     r300->zmask_in_use = FALSE;
    407     r300_mark_atom_dirty(r300, &r300->hyperz_state);
    408 }
    409 
    410 void r300_decompress_zmask_locked_unsafe(struct r300_context *r300)
    411 {
    412     struct pipe_framebuffer_state fb;
    413 
    414     memset(&fb, 0, sizeof(fb));
    415     fb.width = r300->locked_zbuffer->width;
    416     fb.height = r300->locked_zbuffer->height;
    417     fb.zsbuf = r300->locked_zbuffer;
    418 
    419     r300->context.set_framebuffer_state(&r300->context, &fb);
    420     r300_decompress_zmask(r300);
    421 }
    422 
    423 void r300_decompress_zmask_locked(struct r300_context *r300)
    424 {
    425     struct pipe_framebuffer_state saved_fb;
    426 
    427     memset(&saved_fb, 0, sizeof(saved_fb));
    428     util_copy_framebuffer_state(&saved_fb, r300->fb_state.state);
    429     r300_decompress_zmask_locked_unsafe(r300);
    430     r300->context.set_framebuffer_state(&r300->context, &saved_fb);
    431     util_unreference_framebuffer_state(&saved_fb);
    432 
    433     pipe_surface_reference(&r300->locked_zbuffer, NULL);
    434 }
    435 
    436 bool r300_is_blit_supported(enum pipe_format format)
    437 {
    438     const struct util_format_description *desc =
    439         util_format_description(format);
    440 
    441     return desc->layout == UTIL_FORMAT_LAYOUT_PLAIN ||
    442            desc->layout == UTIL_FORMAT_LAYOUT_S3TC ||
    443            desc->layout == UTIL_FORMAT_LAYOUT_RGTC;
    444 }
    445 
    446 /* Copy a block of pixels from one surface to another. */
    447 static void r300_resource_copy_region(struct pipe_context *pipe,
    448                                       struct pipe_resource *dst,
    449                                       unsigned dst_level,
    450                                       unsigned dstx, unsigned dsty, unsigned dstz,
    451                                       struct pipe_resource *src,
    452                                       unsigned src_level,
    453                                       const struct pipe_box *src_box)
    454 {
    455     struct pipe_screen *screen = pipe->screen;
    456     struct r300_context *r300 = r300_context(pipe);
    457     struct pipe_framebuffer_state *fb =
    458         (struct pipe_framebuffer_state*)r300->fb_state.state;
    459     unsigned src_width0 = r300_resource(src)->tex.width0;
    460     unsigned src_height0 = r300_resource(src)->tex.height0;
    461     unsigned dst_width0 = r300_resource(dst)->tex.width0;
    462     unsigned dst_height0 = r300_resource(dst)->tex.height0;
    463     unsigned layout;
    464     struct pipe_box box;
    465     struct pipe_sampler_view src_templ, *src_view;
    466     struct pipe_surface dst_templ, *dst_view;
    467 
    468     /* Fallback for buffers. */
    469     if ((dst->target == PIPE_BUFFER && src->target == PIPE_BUFFER) ||
    470         !r300_is_blit_supported(dst->format)) {
    471         util_resource_copy_region(pipe, dst, dst_level, dstx, dsty, dstz,
    472                                   src, src_level, src_box);
    473         return;
    474     }
    475 
    476     /* The code below changes the texture format so that the copy can be done
    477      * on hardware. E.g. depth-stencil surfaces are copied as RGBA
    478      * colorbuffers. */
    479 
    480     util_blitter_default_dst_texture(&dst_templ, dst, dst_level, dstz, src_box);
    481     util_blitter_default_src_texture(&src_templ, src, src_level);
    482 
    483     layout = util_format_description(dst_templ.format)->layout;
    484 
    485     /* Handle non-renderable plain formats. */
    486     if (layout == UTIL_FORMAT_LAYOUT_PLAIN &&
    487         (!screen->is_format_supported(screen, src_templ.format, src->target,
    488                                       src->nr_samples,
    489                                       PIPE_BIND_SAMPLER_VIEW) ||
    490          !screen->is_format_supported(screen, dst_templ.format, dst->target,
    491                                       dst->nr_samples,
    492                                       PIPE_BIND_RENDER_TARGET))) {
    493         switch (util_format_get_blocksize(dst_templ.format)) {
    494             case 1:
    495                 dst_templ.format = PIPE_FORMAT_I8_UNORM;
    496                 break;
    497             case 2:
    498                 dst_templ.format = PIPE_FORMAT_B4G4R4A4_UNORM;
    499                 break;
    500             case 4:
    501                 dst_templ.format = PIPE_FORMAT_B8G8R8A8_UNORM;
    502                 break;
    503             case 8:
    504                 dst_templ.format = PIPE_FORMAT_R16G16B16A16_UNORM;
    505                 break;
    506             default:
    507                 debug_printf("r300: copy_region: Unhandled format: %s. Falling back to software.\n"
    508                              "r300: copy_region: Software fallback doesn't work for tiled textures.\n",
    509                              util_format_short_name(dst_templ.format));
    510         }
    511         src_templ.format = dst_templ.format;
    512     }
    513 
    514     /* Handle compressed formats. */
    515     if (layout == UTIL_FORMAT_LAYOUT_S3TC ||
    516         layout == UTIL_FORMAT_LAYOUT_RGTC) {
    517         assert(src_templ.format == dst_templ.format);
    518 
    519         box = *src_box;
    520         src_box = &box;
    521 
    522         dst_width0 = align(dst_width0, 4);
    523         dst_height0 = align(dst_height0, 4);
    524         src_width0 = align(src_width0, 4);
    525         src_height0 = align(src_height0, 4);
    526         box.width = align(box.width, 4);
    527         box.height = align(box.height, 4);
    528 
    529         switch (util_format_get_blocksize(dst_templ.format)) {
    530         case 8:
    531             /* one 4x4 pixel block has 8 bytes.
    532              * we set 1 pixel = 4 bytes ===> 1 block corrensponds to 2 pixels. */
    533             dst_templ.format = PIPE_FORMAT_R8G8B8A8_UNORM;
    534             dst_width0 = dst_width0 / 2;
    535             src_width0 = src_width0 / 2;
    536             dstx /= 2;
    537             box.x /= 2;
    538             box.width /= 2;
    539             break;
    540         case 16:
    541             /* one 4x4 pixel block has 16 bytes.
    542              * we set 1 pixel = 4 bytes ===> 1 block corresponds to 4 pixels. */
    543             dst_templ.format = PIPE_FORMAT_R8G8B8A8_UNORM;
    544             break;
    545         }
    546         src_templ.format = dst_templ.format;
    547 
    548         dst_height0 = dst_height0 / 4;
    549         src_height0 = src_height0 / 4;
    550         dsty /= 4;
    551         box.y /= 4;
    552         box.height /= 4;
    553     }
    554 
    555     /* Fallback for textures. */
    556     if (!screen->is_format_supported(screen, dst_templ.format,
    557                                      dst->target, dst->nr_samples,
    558                                      PIPE_BIND_RENDER_TARGET) ||
    559 	!screen->is_format_supported(screen, src_templ.format,
    560                                      src->target, src->nr_samples,
    561                                      PIPE_BIND_SAMPLER_VIEW)) {
    562         assert(0 && "this shouldn't happen, update r300_is_blit_supported");
    563         util_resource_copy_region(pipe, dst, dst_level, dstx, dsty, dstz,
    564                                   src, src_level, src_box);
    565         return;
    566     }
    567 
    568     /* Decompress ZMASK. */
    569     if (r300->zmask_in_use && !r300->locked_zbuffer) {
    570         if (fb->zsbuf->texture == src ||
    571             fb->zsbuf->texture == dst) {
    572             r300_decompress_zmask(r300);
    573         }
    574     }
    575 
    576     dst_view = r300_create_surface_custom(pipe, dst, &dst_templ, dst_width0, dst_height0);
    577     src_view = r300_create_sampler_view_custom(pipe, src, &src_templ, src_width0, src_height0);
    578 
    579     r300_blitter_begin(r300, R300_COPY);
    580     util_blitter_copy_texture_view(r300->blitter, dst_view, ~0, dstx, dsty,
    581                                    src_view, 0, src_box,
    582                                    src_width0, src_height0, PIPE_MASK_RGBAZS);
    583     r300_blitter_end(r300);
    584 
    585     pipe_surface_reference(&dst_view, NULL);
    586     pipe_sampler_view_reference(&src_view, NULL);
    587 }
    588 
    589 void r300_init_blit_functions(struct r300_context *r300)
    590 {
    591     r300->context.clear = r300_clear;
    592     r300->context.clear_render_target = r300_clear_render_target;
    593     r300->context.clear_depth_stencil = r300_clear_depth_stencil;
    594     r300->context.resource_copy_region = r300_resource_copy_region;
    595 }
    596