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      1 /**************************************************************************
      2  *
      3  * Copyright 2007 VMware, Inc.
      4  * All Rights Reserved.
      5  *
      6  * Permission is hereby granted, free of charge, to any person obtaining a
      7  * copy of this software and associated documentation files (the
      8  * "Software"), to deal in the Software without restriction, including
      9  * without limitation the rights to use, copy, modify, merge, publish,
     10  * distribute, sub license, and/or sell copies of the Software, and to
     11  * permit persons to whom the Software is furnished to do so, subject to
     12  * the following conditions:
     13  *
     14  * The above copyright notice and this permission notice (including the
     15  * next paragraph) shall be included in all copies or substantial portions
     16  * of the Software.
     17  *
     18  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
     19  * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
     20  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.
     21  * IN NO EVENT SHALL VMWARE AND/OR ITS SUPPLIERS BE LIABLE FOR
     22  * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
     23  * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
     24  * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
     25  *
     26  **************************************************************************/
     27 
     28 #include "main/bufferobj.h"
     29 #include "main/image.h"
     30 #include "main/pbo.h"
     31 #include "main/imports.h"
     32 #include "main/readpix.h"
     33 #include "main/enums.h"
     34 #include "main/framebuffer.h"
     35 #include "util/u_inlines.h"
     36 #include "util/u_format.h"
     37 #include "cso_cache/cso_context.h"
     38 
     39 #include "st_cb_fbo.h"
     40 #include "st_atom.h"
     41 #include "st_context.h"
     42 #include "st_cb_bitmap.h"
     43 #include "st_cb_readpixels.h"
     44 #include "st_debug.h"
     45 #include "state_tracker/st_cb_texture.h"
     46 #include "state_tracker/st_format.h"
     47 #include "state_tracker/st_pbo.h"
     48 #include "state_tracker/st_texture.h"
     49 
     50 /* The readpixels cache caches a blitted staging texture so that back-to-back
     51  * calls to glReadPixels with user pointers require less CPU-GPU synchronization.
     52  *
     53  * Assumptions:
     54  *
     55  * (1) Blits have high synchronization overheads, and it is beneficial to
     56  *     use a single blit of the entire framebuffer instead of many smaller
     57  *     blits (because the smaller blits cannot be batched, and we have to wait
     58  *     for the GPU after each one).
     59  *
     60  * (2) transfer_map implicitly involves a blit as well (for de-tiling, copy
     61  *     from VRAM, etc.), so that it is beneficial to replace the
     62  *     _mesa_readpixels path as well when possible.
     63  *
     64  * Change this #define to true to fill and use the cache whenever possible
     65  * (this is inefficient and only meant for testing / debugging).
     66  */
     67 #define ALWAYS_READPIXELS_CACHE false
     68 
     69 static boolean
     70 needs_integer_signed_unsigned_conversion(const struct gl_context *ctx,
     71                                          GLenum format, GLenum type)
     72 {
     73    struct gl_renderbuffer *rb =
     74       _mesa_get_read_renderbuffer_for_format(ctx, format);
     75 
     76    assert(rb);
     77 
     78    GLenum srcType = _mesa_get_format_datatype(rb->Format);
     79 
     80     if ((srcType == GL_INT &&
     81         (type == GL_UNSIGNED_INT ||
     82          type == GL_UNSIGNED_SHORT ||
     83          type == GL_UNSIGNED_BYTE)) ||
     84        (srcType == GL_UNSIGNED_INT &&
     85         (type == GL_INT ||
     86          type == GL_SHORT ||
     87          type == GL_BYTE))) {
     88       return TRUE;
     89    }
     90 
     91    return FALSE;
     92 }
     93 
     94 static bool
     95 try_pbo_readpixels(struct st_context *st, struct st_renderbuffer *strb,
     96                    bool invert_y,
     97                    GLint x, GLint y, GLsizei width, GLsizei height,
     98                    enum pipe_format src_format, enum pipe_format dst_format,
     99                    const struct gl_pixelstore_attrib *pack, void *pixels)
    100 {
    101    struct pipe_context *pipe = st->pipe;
    102    struct pipe_screen *screen = pipe->screen;
    103    struct cso_context *cso = st->cso_context;
    104    struct pipe_surface *surface = strb->surface;
    105    struct pipe_resource *texture = strb->texture;
    106    const struct util_format_description *desc;
    107    struct st_pbo_addresses addr;
    108    struct pipe_framebuffer_state fb;
    109    enum pipe_texture_target view_target;
    110    bool success = false;
    111 
    112    if (texture->nr_samples > 1)
    113       return false;
    114 
    115    if (!screen->is_format_supported(screen, dst_format, PIPE_BUFFER, 0,
    116                                     PIPE_BIND_SHADER_IMAGE))
    117       return false;
    118 
    119    desc = util_format_description(dst_format);
    120 
    121    /* Compute PBO addresses */
    122    addr.bytes_per_pixel = desc->block.bits / 8;
    123    addr.xoffset = x;
    124    addr.yoffset = y;
    125    addr.width = width;
    126    addr.height = height;
    127    addr.depth = 1;
    128    if (!st_pbo_addresses_pixelstore(st, GL_TEXTURE_2D, false, pack, pixels, &addr))
    129       return false;
    130 
    131    cso_save_state(cso, (CSO_BIT_FRAGMENT_SAMPLER_VIEWS |
    132                         CSO_BIT_FRAGMENT_SAMPLERS |
    133                         CSO_BIT_FRAGMENT_IMAGE0 |
    134                         CSO_BIT_BLEND |
    135                         CSO_BIT_VERTEX_ELEMENTS |
    136                         CSO_BIT_AUX_VERTEX_BUFFER_SLOT |
    137                         CSO_BIT_FRAMEBUFFER |
    138                         CSO_BIT_VIEWPORT |
    139                         CSO_BIT_RASTERIZER |
    140                         CSO_BIT_DEPTH_STENCIL_ALPHA |
    141                         CSO_BIT_STREAM_OUTPUTS |
    142                         CSO_BIT_PAUSE_QUERIES |
    143                         CSO_BIT_SAMPLE_MASK |
    144                         CSO_BIT_MIN_SAMPLES |
    145                         CSO_BIT_RENDER_CONDITION |
    146                         CSO_BITS_ALL_SHADERS));
    147    cso_save_constant_buffer_slot0(cso, PIPE_SHADER_FRAGMENT);
    148 
    149    cso_set_sample_mask(cso, ~0);
    150    cso_set_min_samples(cso, 1);
    151    cso_set_render_condition(cso, NULL, FALSE, 0);
    152 
    153    /* Set up the sampler_view */
    154    {
    155       struct pipe_sampler_view templ;
    156       struct pipe_sampler_view *sampler_view;
    157       struct pipe_sampler_state sampler = {0};
    158       const struct pipe_sampler_state *samplers[1] = {&sampler};
    159 
    160       u_sampler_view_default_template(&templ, texture, src_format);
    161 
    162       switch (texture->target) {
    163       case PIPE_TEXTURE_CUBE:
    164       case PIPE_TEXTURE_CUBE_ARRAY:
    165          view_target = PIPE_TEXTURE_2D_ARRAY;
    166          break;
    167       default:
    168          view_target = texture->target;
    169          break;
    170       }
    171 
    172       templ.target = view_target;
    173       templ.u.tex.first_level = surface->u.tex.level;
    174       templ.u.tex.last_level = templ.u.tex.first_level;
    175 
    176       if (view_target != PIPE_TEXTURE_3D) {
    177          templ.u.tex.first_layer = surface->u.tex.first_layer;
    178          templ.u.tex.last_layer = templ.u.tex.first_layer;
    179       } else {
    180          addr.constants.layer_offset = surface->u.tex.first_layer;
    181       }
    182 
    183       sampler_view = pipe->create_sampler_view(pipe, texture, &templ);
    184       if (sampler_view == NULL)
    185          goto fail;
    186 
    187       cso_set_sampler_views(cso, PIPE_SHADER_FRAGMENT, 1, &sampler_view);
    188 
    189       pipe_sampler_view_reference(&sampler_view, NULL);
    190 
    191       cso_set_samplers(cso, PIPE_SHADER_FRAGMENT, 1, samplers);
    192    }
    193 
    194    /* Set up destination image */
    195    {
    196       struct pipe_image_view image;
    197 
    198       memset(&image, 0, sizeof(image));
    199       image.resource = addr.buffer;
    200       image.format = dst_format;
    201       image.access = PIPE_IMAGE_ACCESS_WRITE;
    202       image.u.buf.offset = addr.first_element * addr.bytes_per_pixel;
    203       image.u.buf.size = (addr.last_element - addr.first_element + 1) *
    204                          addr.bytes_per_pixel;
    205 
    206       cso_set_shader_images(cso, PIPE_SHADER_FRAGMENT, 0, 1, &image);
    207    }
    208 
    209    /* Set up no-attachment framebuffer */
    210    memset(&fb, 0, sizeof(fb));
    211    fb.width = surface->width;
    212    fb.height = surface->height;
    213    fb.samples = 1;
    214    fb.layers = 1;
    215    cso_set_framebuffer(cso, &fb);
    216 
    217    /* Any blend state would do. Set this just to prevent drivers having
    218     * blend == NULL.
    219     */
    220    cso_set_blend(cso, &st->pbo.upload_blend);
    221 
    222    cso_set_viewport_dims(cso, fb.width, fb.height, invert_y);
    223 
    224    if (invert_y)
    225       st_pbo_addresses_invert_y(&addr, fb.height);
    226 
    227    {
    228       struct pipe_depth_stencil_alpha_state dsa;
    229       memset(&dsa, 0, sizeof(dsa));
    230       cso_set_depth_stencil_alpha(cso, &dsa);
    231    }
    232 
    233    /* Set up the fragment shader */
    234    {
    235       void *fs = st_pbo_get_download_fs(st, view_target, src_format, dst_format);
    236       if (!fs)
    237          goto fail;
    238 
    239       cso_set_fragment_shader_handle(cso, fs);
    240    }
    241 
    242    success = st_pbo_draw(st, &addr, fb.width, fb.height);
    243 
    244    /* Buffer written via shader images needs explicit synchronization. */
    245    pipe->memory_barrier(pipe, PIPE_BARRIER_ALL);
    246 
    247 fail:
    248    cso_restore_state(cso);
    249    cso_restore_constant_buffer_slot0(cso, PIPE_SHADER_FRAGMENT);
    250 
    251    return success;
    252 }
    253 
    254 /**
    255  * Create a staging texture and blit the requested region to it.
    256  */
    257 static struct pipe_resource *
    258 blit_to_staging(struct st_context *st, struct st_renderbuffer *strb,
    259                    bool invert_y,
    260                    GLint x, GLint y, GLsizei width, GLsizei height,
    261                    GLenum format,
    262                    enum pipe_format src_format, enum pipe_format dst_format)
    263 {
    264    struct pipe_context *pipe = st->pipe;
    265    struct pipe_screen *screen = pipe->screen;
    266    struct pipe_resource dst_templ;
    267    struct pipe_resource *dst;
    268    struct pipe_blit_info blit;
    269 
    270    /* We are creating a texture of the size of the region being read back.
    271     * Need to check for NPOT texture support. */
    272    if (!screen->get_param(screen, PIPE_CAP_NPOT_TEXTURES) &&
    273        (!util_is_power_of_two(width) ||
    274         !util_is_power_of_two(height)))
    275       return NULL;
    276 
    277    /* create the destination texture */
    278    memset(&dst_templ, 0, sizeof(dst_templ));
    279    dst_templ.target = PIPE_TEXTURE_2D;
    280    dst_templ.format = dst_format;
    281    if (util_format_is_depth_or_stencil(dst_format))
    282       dst_templ.bind |= PIPE_BIND_DEPTH_STENCIL;
    283    else
    284       dst_templ.bind |= PIPE_BIND_RENDER_TARGET;
    285    dst_templ.usage = PIPE_USAGE_STAGING;
    286 
    287    st_gl_texture_dims_to_pipe_dims(GL_TEXTURE_2D, width, height, 1,
    288                                    &dst_templ.width0, &dst_templ.height0,
    289                                    &dst_templ.depth0, &dst_templ.array_size);
    290 
    291    dst = screen->resource_create(screen, &dst_templ);
    292    if (!dst)
    293       return NULL;
    294 
    295    memset(&blit, 0, sizeof(blit));
    296    blit.src.resource = strb->texture;
    297    blit.src.level = strb->surface->u.tex.level;
    298    blit.src.format = src_format;
    299    blit.dst.resource = dst;
    300    blit.dst.level = 0;
    301    blit.dst.format = dst->format;
    302    blit.src.box.x = x;
    303    blit.dst.box.x = 0;
    304    blit.src.box.y = y;
    305    blit.dst.box.y = 0;
    306    blit.src.box.z = strb->surface->u.tex.first_layer;
    307    blit.dst.box.z = 0;
    308    blit.src.box.width = blit.dst.box.width = width;
    309    blit.src.box.height = blit.dst.box.height = height;
    310    blit.src.box.depth = blit.dst.box.depth = 1;
    311    blit.mask = st_get_blit_mask(strb->Base._BaseFormat, format);
    312    blit.filter = PIPE_TEX_FILTER_NEAREST;
    313    blit.scissor_enable = FALSE;
    314 
    315    if (invert_y) {
    316       blit.src.box.y = strb->Base.Height - blit.src.box.y;
    317       blit.src.box.height = -blit.src.box.height;
    318    }
    319 
    320    /* blit */
    321    st->pipe->blit(st->pipe, &blit);
    322 
    323    return dst;
    324 }
    325 
    326 static struct pipe_resource *
    327 try_cached_readpixels(struct st_context *st, struct st_renderbuffer *strb,
    328                       bool invert_y,
    329                       GLsizei width, GLsizei height,
    330                       GLenum format,
    331                       enum pipe_format src_format, enum pipe_format dst_format)
    332 {
    333    struct pipe_resource *src = strb->texture;
    334    struct pipe_resource *dst = NULL;
    335 
    336    if (ST_DEBUG & DEBUG_NOREADPIXCACHE)
    337       return NULL;
    338 
    339    /* Reset cache after invalidation or switch of parameters. */
    340    if (st->readpix_cache.src != src ||
    341        st->readpix_cache.dst_format != dst_format ||
    342        st->readpix_cache.level != strb->surface->u.tex.level ||
    343        st->readpix_cache.layer != strb->surface->u.tex.first_layer) {
    344       pipe_resource_reference(&st->readpix_cache.src, src);
    345       pipe_resource_reference(&st->readpix_cache.cache, NULL);
    346       st->readpix_cache.dst_format = dst_format;
    347       st->readpix_cache.level = strb->surface->u.tex.level;
    348       st->readpix_cache.layer = strb->surface->u.tex.first_layer;
    349       st->readpix_cache.hits = 0;
    350    }
    351 
    352    /* Decide whether to trigger the cache. */
    353    if (!st->readpix_cache.cache) {
    354       if (!strb->use_readpix_cache && !ALWAYS_READPIXELS_CACHE) {
    355          /* Heuristic: If previous successive calls read at least a fraction
    356           * of the surface _and_ we read again, trigger the cache.
    357           */
    358          unsigned threshold = MAX2(1, strb->Base.Width * strb->Base.Height / 8);
    359 
    360          if (st->readpix_cache.hits < threshold) {
    361             st->readpix_cache.hits += width * height;
    362             return NULL;
    363          }
    364 
    365          strb->use_readpix_cache = true;
    366       }
    367 
    368       /* Fill the cache */
    369       st->readpix_cache.cache = blit_to_staging(st, strb, invert_y,
    370                                                 0, 0,
    371                                                 strb->Base.Width,
    372                                                 strb->Base.Height, format,
    373                                                 src_format, dst_format);
    374    }
    375 
    376    /* Return an owning reference to stay consistent with the non-cached path */
    377    pipe_resource_reference(&dst, st->readpix_cache.cache);
    378 
    379    return dst;
    380 }
    381 
    382 /**
    383  * This uses a blit to copy the read buffer to a texture format which matches
    384  * the format and type combo and then a fast read-back is done using memcpy.
    385  * We can do arbitrary X/Y/Z/W/0/1 swizzling here as long as there is
    386  * a format which matches the swizzling.
    387  *
    388  * If such a format isn't available, we fall back to _mesa_readpixels.
    389  *
    390  * NOTE: Some drivers use a blit to convert between tiled and linear
    391  *       texture layouts during texture uploads/downloads, so the blit
    392  *       we do here should be free in such cases.
    393  */
    394 static void
    395 st_ReadPixels(struct gl_context *ctx, GLint x, GLint y,
    396               GLsizei width, GLsizei height,
    397               GLenum format, GLenum type,
    398               const struct gl_pixelstore_attrib *pack,
    399               void *pixels)
    400 {
    401    struct st_context *st = st_context(ctx);
    402    struct gl_renderbuffer *rb =
    403          _mesa_get_read_renderbuffer_for_format(ctx, format);
    404    struct st_renderbuffer *strb = st_renderbuffer(rb);
    405    struct pipe_context *pipe = st->pipe;
    406    struct pipe_screen *screen = pipe->screen;
    407    struct pipe_resource *src;
    408    struct pipe_resource *dst = NULL;
    409    enum pipe_format dst_format, src_format;
    410    unsigned bind;
    411    struct pipe_transfer *tex_xfer;
    412    ubyte *map = NULL;
    413    int dst_x, dst_y;
    414 
    415    /* Validate state (to be sure we have up-to-date framebuffer surfaces)
    416     * and flush the bitmap cache prior to reading. */
    417    st_validate_state(st, ST_PIPELINE_UPDATE_FRAMEBUFFER);
    418    st_flush_bitmap_cache(st);
    419 
    420    if (!st->prefer_blit_based_texture_transfer) {
    421       goto fallback;
    422    }
    423 
    424    /* This must be done after state validation. */
    425    src = strb->texture;
    426 
    427    /* XXX Fallback for depth-stencil formats due to an incomplete
    428     * stencil blit implementation in some drivers. */
    429    if (format == GL_DEPTH_STENCIL) {
    430       goto fallback;
    431    }
    432 
    433    /* If the base internal format and the texture format don't match, we have
    434     * to use the slow path. */
    435    if (rb->_BaseFormat !=
    436        _mesa_get_format_base_format(rb->Format)) {
    437       goto fallback;
    438    }
    439 
    440    if (_mesa_readpixels_needs_slow_path(ctx, format, type, GL_TRUE)) {
    441       goto fallback;
    442    }
    443 
    444    /* Convert the source format to what is expected by ReadPixels
    445     * and see if it's supported. */
    446    src_format = util_format_linear(src->format);
    447    src_format = util_format_luminance_to_red(src_format);
    448    src_format = util_format_intensity_to_red(src_format);
    449 
    450    if (!src_format ||
    451        !screen->is_format_supported(screen, src_format, src->target,
    452                                     src->nr_samples,
    453                                     PIPE_BIND_SAMPLER_VIEW)) {
    454       goto fallback;
    455    }
    456 
    457    if (format == GL_DEPTH_COMPONENT || format == GL_DEPTH_STENCIL)
    458       bind = PIPE_BIND_DEPTH_STENCIL;
    459    else
    460       bind = PIPE_BIND_RENDER_TARGET;
    461 
    462    /* Choose the destination format by finding the best match
    463     * for the format+type combo. */
    464    dst_format = st_choose_matching_format(st, bind, format, type,
    465                                           pack->SwapBytes);
    466    if (dst_format == PIPE_FORMAT_NONE) {
    467       goto fallback;
    468    }
    469 
    470    if (st->pbo.download_enabled && _mesa_is_bufferobj(pack->BufferObj)) {
    471       if (try_pbo_readpixels(st, strb,
    472                              st_fb_orientation(ctx->ReadBuffer) == Y_0_TOP,
    473                              x, y, width, height,
    474                              src_format, dst_format,
    475                              pack, pixels))
    476          return;
    477    }
    478 
    479    if (needs_integer_signed_unsigned_conversion(ctx, format, type)) {
    480       goto fallback;
    481    }
    482 
    483    /* Cache a staging texture for back-to-back ReadPixels, to avoid CPU-GPU
    484     * synchronization overhead.
    485     */
    486    dst = try_cached_readpixels(st, strb,
    487                                st_fb_orientation(ctx->ReadBuffer) == Y_0_TOP,
    488                                width, height, format, src_format, dst_format);
    489    if (dst) {
    490       dst_x = x;
    491       dst_y = y;
    492    } else {
    493       /* See if the texture format already matches the format and type,
    494        * in which case the memcpy-based fast path will likely be used and
    495        * we don't have to blit. */
    496       if (_mesa_format_matches_format_and_type(rb->Format, format,
    497                                                type, pack->SwapBytes, NULL)) {
    498          goto fallback;
    499       }
    500 
    501       dst = blit_to_staging(st, strb,
    502                             st_fb_orientation(ctx->ReadBuffer) == Y_0_TOP,
    503                             x, y, width, height, format,
    504                             src_format, dst_format);
    505       if (!dst)
    506          goto fallback;
    507 
    508       dst_x = 0;
    509       dst_y = 0;
    510    }
    511 
    512    /* map resources */
    513    pixels = _mesa_map_pbo_dest(ctx, pack, pixels);
    514 
    515    map = pipe_transfer_map_3d(pipe, dst, 0, PIPE_TRANSFER_READ,
    516                               dst_x, dst_y, 0, width, height, 1, &tex_xfer);
    517    if (!map) {
    518       _mesa_unmap_pbo_dest(ctx, pack);
    519       pipe_resource_reference(&dst, NULL);
    520       goto fallback;
    521    }
    522 
    523    /* memcpy data into a user buffer */
    524    {
    525       const uint bytesPerRow = width * util_format_get_blocksize(dst_format);
    526       const int destStride = _mesa_image_row_stride(pack, width, format, type);
    527       char *dest = _mesa_image_address2d(pack, pixels,
    528                                          width, height, format,
    529                                          type, 0, 0);
    530 
    531       if (tex_xfer->stride == bytesPerRow && destStride == bytesPerRow) {
    532          memcpy(dest, map, bytesPerRow * height);
    533       } else {
    534          GLuint row;
    535 
    536          for (row = 0; row < (unsigned) height; row++) {
    537             memcpy(dest, map, bytesPerRow);
    538             map += tex_xfer->stride;
    539             dest += destStride;
    540          }
    541       }
    542    }
    543 
    544    pipe_transfer_unmap(pipe, tex_xfer);
    545    _mesa_unmap_pbo_dest(ctx, pack);
    546    pipe_resource_reference(&dst, NULL);
    547    return;
    548 
    549 fallback:
    550    _mesa_readpixels(ctx, x, y, width, height, format, type, pack, pixels);
    551 }
    552 
    553 void st_init_readpixels_functions(struct dd_function_table *functions)
    554 {
    555    functions->ReadPixels = st_ReadPixels;
    556 }
    557