src/mesa/state_tracker/st_cb_readpixels.c

   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.last_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 }