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
  32 #include "main/readpix.h"
  33 #include "main/enums.h"
  34 #include "main/framebuffer.h"
  35 #include "util/u_inlines.h"
  36 #include "util/format/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 #include "state_tracker/st_util.h"
  50
  51
  52 /* The readpixels cache caches a blitted staging texture so that back-to-back
  53  * calls to glReadPixels with user pointers require less CPU-GPU synchronization.
  54  *
  55  * Assumptions:
  56  *
  57  * (1) Blits have high synchronization overheads, and it is beneficial to
  58  *     use a single blit of the entire framebuffer instead of many smaller
  59  *     blits (because the smaller blits cannot be batched, and we have to wait
  60  *     for the GPU after each one).
  61  *
  62  * (2) transfer_map implicitly involves a blit as well (for de-tiling, copy
  63  *     from VRAM, etc.), so that it is beneficial to replace the
  64  *     _mesa_readpixels path as well when possible.
  65  *
  66  * Change this #define to true to fill and use the cache whenever possible
  67  * (this is inefficient and only meant for testing / debugging).
  68  */
  69 #define ALWAYS_READPIXELS_CACHE false
  70
  71 static boolean
  72 needs_integer_signed_unsigned_conversion(const struct gl_context *ctx,
  73                                          GLenum format, GLenum type)
  74 {
  75    struct gl_renderbuffer *rb =
  76       _mesa_get_read_renderbuffer_for_format(ctx, format);
  77
  78    assert(rb);
  79
  80    GLenum srcType = _mesa_get_format_datatype(rb->Format);
  81
  82     if ((srcType == GL_INT &&
  83         (type == GL_UNSIGNED_INT ||
  84          type == GL_UNSIGNED_SHORT ||
  85          type == GL_UNSIGNED_BYTE)) ||
  86        (srcType == GL_UNSIGNED_INT &&
  87         (type == GL_INT ||
  88          type == GL_SHORT ||
  89          type == GL_BYTE))) {
  90       return TRUE;
  91    }
  92
  93    return FALSE;
  94 }
  95
  96 static bool
  97 try_pbo_readpixels(struct st_context *st, struct st_renderbuffer *strb,
  98                    bool invert_y,
  99                    GLint x, GLint y, GLsizei width, GLsizei height,
 100                    enum pipe_format src_format, enum pipe_format dst_format,
 101                    const struct gl_pixelstore_attrib *pack, void *pixels)
 102 {
 103    struct pipe_context *pipe = st->pipe;
 104    struct pipe_screen *screen = pipe->screen;
 105    struct cso_context *cso = st->cso_context;
 106    struct pipe_surface *surface = strb->surface;
 107    struct pipe_resource *texture = strb->texture;
 108    const struct util_format_description *desc;
 109    struct st_pbo_addresses addr;
 110    struct pipe_framebuffer_state fb;
 111    enum pipe_texture_target view_target;
 112    bool success = false;
 113
 114    if (texture->nr_samples > 1)
 115       return false;
 116
 117    if (!screen->is_format_supported(screen, dst_format, PIPE_BUFFER, 0, 0,
 118                                     PIPE_BIND_SHADER_IMAGE))
 119       return false;
 120
 121    desc = util_format_description(dst_format);
 122
 123    /* Compute PBO addresses */
 124    addr.bytes_per_pixel = desc->block.bits / 8;
 125    addr.xoffset = x;
 126    addr.yoffset = y;
 127    addr.width = width;
 128    addr.height = height;
 129    addr.depth = 1;
 130    if (!st_pbo_addresses_pixelstore(st, GL_TEXTURE_2D, false, pack, pixels, &addr))
 131       return false;
 132
 133    cso_save_state(cso, (CSO_BIT_FRAGMENT_SAMPLER_VIEWS |
 134                         CSO_BIT_FRAGMENT_SAMPLERS |
 135                         CSO_BIT_FRAGMENT_IMAGE0 |
 136                         CSO_BIT_BLEND |
 137                         CSO_BIT_VERTEX_ELEMENTS |
 138                         CSO_BIT_AUX_VERTEX_BUFFER_SLOT |
 139                         CSO_BIT_FRAMEBUFFER |
 140                         CSO_BIT_VIEWPORT |
 141                         CSO_BIT_RASTERIZER |
 142                         CSO_BIT_DEPTH_STENCIL_ALPHA |
 143                         CSO_BIT_STREAM_OUTPUTS |
 144                         (st->active_queries ? CSO_BIT_PAUSE_QUERIES : 0) |
 145                         CSO_BIT_SAMPLE_MASK |
 146                         CSO_BIT_MIN_SAMPLES |
 147                         CSO_BIT_RENDER_CONDITION |
 148                         CSO_BITS_ALL_SHADERS));
 149    cso_save_constant_buffer_slot0(cso, PIPE_SHADER_FRAGMENT);
 150
 151    cso_set_sample_mask(cso, ~0);
 152    cso_set_min_samples(cso, 1);
 153    cso_set_render_condition(cso, NULL, FALSE, 0);
 154
 155    /* Set up the sampler_view */
 156    {
 157       struct pipe_sampler_view templ;
 158       struct pipe_sampler_view *sampler_view;
 159       struct pipe_sampler_state sampler = {0};
 160       const struct pipe_sampler_state *samplers[1] = {&sampler};
 161
 162       u_sampler_view_default_template(&templ, texture, src_format);
 163
 164       switch (texture->target) {
 165       case PIPE_TEXTURE_CUBE:
 166       case PIPE_TEXTURE_CUBE_ARRAY:
 167          view_target = PIPE_TEXTURE_2D_ARRAY;
 168          break;
 169       default:
 170          view_target = texture->target;
 171          break;
 172       }
 173
 174       templ.target = view_target;
 175       templ.u.tex.first_level = surface->u.tex.level;
 176       templ.u.tex.last_level = templ.u.tex.first_level;
 177
 178       if (view_target != PIPE_TEXTURE_3D) {
 179          templ.u.tex.first_layer = surface->u.tex.first_layer;
 180          templ.u.tex.last_layer = templ.u.tex.first_layer;
 181       } else {
 182          addr.constants.layer_offset = surface->u.tex.first_layer;
 183       }
 184
 185       sampler_view = pipe->create_sampler_view(pipe, texture, &templ);
 186       if (sampler_view == NULL)
 187          goto fail;
 188
 189       cso_set_sampler_views(cso, PIPE_SHADER_FRAGMENT, 1, &sampler_view);
 190
 191       pipe_sampler_view_reference(&sampler_view, NULL);
 192
 193       cso_set_samplers(cso, PIPE_SHADER_FRAGMENT, 1, samplers);
 194    }
 195
 196    /* Set up destination image */
 197    {
 198       struct pipe_image_view image;
 199
 200       memset(&image, 0, sizeof(image));
 201       image.resource = addr.buffer;
 202       image.format = dst_format;
 203       image.access = PIPE_IMAGE_ACCESS_WRITE;
 204       image.shader_access = PIPE_IMAGE_ACCESS_WRITE;
 205       image.u.buf.offset = addr.first_element * addr.bytes_per_pixel;
 206       image.u.buf.size = (addr.last_element - addr.first_element + 1) *
 207                          addr.bytes_per_pixel;
 208
 209       cso_set_shader_images(cso, PIPE_SHADER_FRAGMENT, 0, 1, &image);
 210    }
 211
 212    /* Set up no-attachment framebuffer */
 213    memset(&fb, 0, sizeof(fb));
 214    fb.width = surface->width;
 215    fb.height = surface->height;
 216    fb.samples = 1;
 217    fb.layers = 1;
 218    cso_set_framebuffer(cso, &fb);
 219
 220    /* Any blend state would do. Set this just to prevent drivers having
 221     * blend == NULL.
 222     */
 223    cso_set_blend(cso, &st->pbo.upload_blend);
 224
 225    cso_set_viewport_dims(cso, fb.width, fb.height, invert_y);
 226
 227    if (invert_y)
 228       st_pbo_addresses_invert_y(&addr, fb.height);
 229
 230    {
 231       struct pipe_depth_stencil_alpha_state dsa;
 232       memset(&dsa, 0, sizeof(dsa));
 233       cso_set_depth_stencil_alpha(cso, &dsa);
 234    }
 235
 236    /* Set up the fragment shader */
 237    {
 238       void *fs = st_pbo_get_download_fs(st, view_target, src_format, dst_format);
 239       if (!fs)
 240          goto fail;
 241
 242       cso_set_fragment_shader_handle(cso, fs);
 243    }
 244
 245    success = st_pbo_draw(st, &addr, fb.width, fb.height);
 246
 247    /* Buffer written via shader images needs explicit synchronization. */
 248    pipe->memory_barrier(pipe, PIPE_BARRIER_ALL);
 249
 250 fail:
 251    cso_restore_state(cso);
 252    cso_restore_constant_buffer_slot0(cso, PIPE_SHADER_FRAGMENT);
 253
 254    return success;
 255 }
 256
 257 /**
 258  * Create a staging texture and blit the requested region to it.
 259  */
 260 static struct pipe_resource *
 261 blit_to_staging(struct st_context *st, struct st_renderbuffer *strb,
 262                    bool invert_y,
 263                    GLint x, GLint y, GLsizei width, GLsizei height,
 264                    GLenum format,
 265                    enum pipe_format src_format, enum pipe_format dst_format)
 266 {
 267    struct pipe_context *pipe = st->pipe;
 268    struct pipe_screen *screen = pipe->screen;
 269    struct pipe_resource dst_templ;
 270    struct pipe_resource *dst;
 271    struct pipe_blit_info blit;
 272
 273    /* We are creating a texture of the size of the region being read back.
 274     * Need to check for NPOT texture support. */
 275    if (!screen->get_param(screen, PIPE_CAP_NPOT_TEXTURES) &&
 276        (!util_is_power_of_two_or_zero(width) ||
 277         !util_is_power_of_two_or_zero(height)))
 278       return NULL;
 279
 280    /* create the destination texture */
 281    memset(&dst_templ, 0, sizeof(dst_templ));
 282    dst_templ.target = PIPE_TEXTURE_2D;
 283    dst_templ.format = dst_format;
 284    if (util_format_is_depth_or_stencil(dst_format))
 285       dst_templ.bind |= PIPE_BIND_DEPTH_STENCIL;
 286    else
 287       dst_templ.bind |= PIPE_BIND_RENDER_TARGET;
 288    dst_templ.usage = PIPE_USAGE_STAGING;
 289
 290    st_gl_texture_dims_to_pipe_dims(GL_TEXTURE_2D, width, height, 1,
 291                                    &dst_templ.width0, &dst_templ.height0,
 292                                    &dst_templ.depth0, &dst_templ.array_size);
 293
 294    dst = screen->resource_create(screen, &dst_templ);
 295    if (!dst)
 296       return NULL;
 297
 298    memset(&blit, 0, sizeof(blit));
 299    blit.src.resource = strb->texture;
 300    blit.src.level = strb->surface->u.tex.level;
 301    blit.src.format = src_format;
 302    blit.dst.resource = dst;
 303    blit.dst.level = 0;
 304    blit.dst.format = dst->format;
 305    blit.src.box.x = x;
 306    blit.dst.box.x = 0;
 307    blit.src.box.y = y;
 308    blit.dst.box.y = 0;
 309    blit.src.box.z = strb->surface->u.tex.first_layer;
 310    blit.dst.box.z = 0;
 311    blit.src.box.width = blit.dst.box.width = width;
 312    blit.src.box.height = blit.dst.box.height = height;
 313    blit.src.box.depth = blit.dst.box.depth = 1;
 314    blit.mask = st_get_blit_mask(strb->Base._BaseFormat, format);
 315    blit.filter = PIPE_TEX_FILTER_NEAREST;
 316    blit.scissor_enable = FALSE;
 317
 318    if (invert_y) {
 319       blit.src.box.y = strb->Base.Height - blit.src.box.y;
 320       blit.src.box.height = -blit.src.box.height;
 321    }
 322
 323    /* blit */
 324    st->pipe->blit(st->pipe, &blit);
 325
 326    return dst;
 327 }
 328
 329 static struct pipe_resource *
 330 try_cached_readpixels(struct st_context *st, struct st_renderbuffer *strb,
 331                       bool invert_y,
 332                       GLsizei width, GLsizei height,
 333                       GLenum format,
 334                       enum pipe_format src_format, enum pipe_format dst_format)
 335 {
 336    struct pipe_resource *src = strb->texture;
 337    struct pipe_resource *dst = NULL;
 338
 339    if (ST_DEBUG & DEBUG_NOREADPIXCACHE)
 340       return NULL;
 341
 342    /* Reset cache after invalidation or switch of parameters. */
 343    if (st->readpix_cache.src != src ||
 344        st->readpix_cache.dst_format != dst_format ||
 345        st->readpix_cache.level != strb->surface->u.tex.level ||
 346        st->readpix_cache.layer != strb->surface->u.tex.first_layer) {
 347       pipe_resource_reference(&st->readpix_cache.src, src);
 348       pipe_resource_reference(&st->readpix_cache.cache, NULL);
 349       st->readpix_cache.dst_format = dst_format;
 350       st->readpix_cache.level = strb->surface->u.tex.level;
 351       st->readpix_cache.layer = strb->surface->u.tex.first_layer;
 352       st->readpix_cache.hits = 0;
 353    }
 354
 355    /* Decide whether to trigger the cache. */
 356    if (!st->readpix_cache.cache) {
 357       if (!strb->use_readpix_cache && !ALWAYS_READPIXELS_CACHE) {
 358          /* Heuristic: If previous successive calls read at least a fraction
 359           * of the surface _and_ we read again, trigger the cache.
 360           */
 361          unsigned threshold = MAX2(1, strb->Base.Width * strb->Base.Height / 8);
 362
 363          if (st->readpix_cache.hits < threshold) {
 364             st->readpix_cache.hits += width * height;
 365             return NULL;
 366          }
 367
 368          strb->use_readpix_cache = true;
 369       }
 370
 371       /* Fill the cache */
 372       st->readpix_cache.cache = blit_to_staging(st, strb, invert_y,
 373                                                 0, 0,
 374                                                 strb->Base.Width,
 375                                                 strb->Base.Height, format,
 376                                                 src_format, dst_format);
 377    }
 378
 379    /* Return an owning reference to stay consistent with the non-cached path */
 380    pipe_resource_reference(&dst, st->readpix_cache.cache);
 381
 382    return dst;
 383 }
 384
 385 /**
 386  * This uses a blit to copy the read buffer to a texture format which matches
 387  * the format and type combo and then a fast read-back is done using memcpy.
 388  * We can do arbitrary X/Y/Z/W/0/1 swizzling here as long as there is
 389  * a format which matches the swizzling.
 390  *
 391  * If such a format isn't available, we fall back to _mesa_readpixels.
 392  *
 393  * NOTE: Some drivers use a blit to convert between tiled and linear
 394  *       texture layouts during texture uploads/downloads, so the blit
 395  *       we do here should be free in such cases.
 396  */
 397 static void
 398 st_ReadPixels(struct gl_context *ctx, GLint x, GLint y,
 399               GLsizei width, GLsizei height,
 400               GLenum format, GLenum type,
 401               const struct gl_pixelstore_attrib *pack,
 402               void *pixels)
 403 {
 404    struct st_context *st = st_context(ctx);
 405    struct gl_renderbuffer *rb =
 406          _mesa_get_read_renderbuffer_for_format(ctx, format);
 407    struct st_renderbuffer *strb = st_renderbuffer(rb);
 408    struct pipe_context *pipe = st->pipe;
 409    struct pipe_screen *screen = pipe->screen;
 410    struct pipe_resource *src;
 411    struct pipe_resource *dst = NULL;
 412    enum pipe_format dst_format, src_format;
 413    unsigned bind;
 414    struct pipe_transfer *tex_xfer;
 415    ubyte *map = NULL;
 416    int dst_x, dst_y;
 417
 418    /* Validate state (to be sure we have up-to-date framebuffer surfaces)
 419     * and flush the bitmap cache prior to reading. */
 420    st_validate_state(st, ST_PIPELINE_UPDATE_FRAMEBUFFER);
 421    st_flush_bitmap_cache(st);
 422
 423    if (!st->prefer_blit_based_texture_transfer) {
 424       goto fallback;
 425    }
 426
 427    /* This must be done after state validation. */
 428    src = strb->texture;
 429
 430    /* XXX Fallback for depth-stencil formats due to an incomplete
 431     * stencil blit implementation in some drivers. */
 432    if (format == GL_DEPTH_STENCIL) {
 433       goto fallback;
 434    }
 435
 436    /* If the base internal format and the texture format don't match, we have
 437     * to use the slow path. */
 438    if (rb->_BaseFormat !=
 439        _mesa_get_format_base_format(rb->Format)) {
 440       goto fallback;
 441    }
 442
 443    if (_mesa_readpixels_needs_slow_path(ctx, format, type, GL_TRUE)) {
 444       goto fallback;
 445    }
 446
 447    /* Convert the source format to what is expected by ReadPixels
 448     * and see if it's supported. */
 449    src_format = util_format_linear(src->format);
 450    src_format = util_format_luminance_to_red(src_format);
 451    src_format = util_format_intensity_to_red(src_format);
 452
 453    if (!src_format ||
 454        !screen->is_format_supported(screen, src_format, src->target,
 455                                     src->nr_samples, src->nr_storage_samples,
 456                                     PIPE_BIND_SAMPLER_VIEW)) {
 457       goto fallback;
 458    }
 459
 460    if (format == GL_DEPTH_COMPONENT || format == GL_DEPTH_STENCIL)
 461       bind = PIPE_BIND_DEPTH_STENCIL;
 462    else
 463       bind = PIPE_BIND_RENDER_TARGET;
 464
 465    /* Choose the destination format by finding the best match
 466     * for the format+type combo. */
 467    dst_format = st_choose_matching_format(st, bind, format, type,
 468                                           pack->SwapBytes);
 469    if (dst_format == PIPE_FORMAT_NONE) {
 470       goto fallback;
 471    }
 472
 473    if (st->pbo.download_enabled && pack->BufferObj) {
 474       if (try_pbo_readpixels(st, strb,
 475                              st_fb_orientation(ctx->ReadBuffer) == Y_0_TOP,
 476                              x, y, width, height,
 477                              src_format, dst_format,
 478                              pack, pixels))
 479          return;
 480    }
 481
 482    if (needs_integer_signed_unsigned_conversion(ctx, format, type)) {
 483       goto fallback;
 484    }
 485
 486    /* Cache a staging texture for back-to-back ReadPixels, to avoid CPU-GPU
 487     * synchronization overhead.
 488     */
 489    dst = try_cached_readpixels(st, strb,
 490                                st_fb_orientation(ctx->ReadBuffer) == Y_0_TOP,
 491                                width, height, format, src_format, dst_format);
 492    if (dst) {
 493       dst_x = x;
 494       dst_y = y;
 495    } else {
 496       /* See if the texture format already matches the format and type,
 497        * in which case the memcpy-based fast path will likely be used and
 498        * we don't have to blit. */
 499       if (_mesa_format_matches_format_and_type(rb->Format, format,
 500                                                type, pack->SwapBytes, NULL)) {
 501          goto fallback;
 502       }
 503
 504       dst = blit_to_staging(st, strb,
 505                             st_fb_orientation(ctx->ReadBuffer) == Y_0_TOP,
 506                             x, y, width, height, format,
 507                             src_format, dst_format);
 508       if (!dst)
 509          goto fallback;
 510
 511       dst_x = 0;
 512       dst_y = 0;
 513    }
 514
 515    /* map resources */
 516    pixels = _mesa_map_pbo_dest(ctx, pack, pixels);
 517
 518    map = pipe_transfer_map_3d(pipe, dst, 0, PIPE_TRANSFER_READ,
 519                               dst_x, dst_y, 0, width, height, 1, &tex_xfer);
 520    if (!map) {
 521       _mesa_unmap_pbo_dest(ctx, pack);
 522       pipe_resource_reference(&dst, NULL);
 523       goto fallback;
 524    }
 525
 526    /* memcpy data into a user buffer */
 527    {
 528       const uint bytesPerRow = width * util_format_get_blocksize(dst_format);
 529       const int destStride = _mesa_image_row_stride(pack, width, format, type);
 530       char *dest = _mesa_image_address2d(pack, pixels,
 531                                          width, height, format,
 532                                          type, 0, 0);
 533
 534       if (tex_xfer->stride == bytesPerRow && destStride == bytesPerRow) {
 535          memcpy(dest, map, bytesPerRow * height);
 536       } else {
 537          GLuint row;
 538
 539          for (row = 0; row < (unsigned) height; row++) {
 540             memcpy(dest, map, bytesPerRow);
 541             map += tex_xfer->stride;
 542             dest += destStride;
 543          }
 544       }
 545    }
 546
 547    pipe_transfer_unmap(pipe, tex_xfer);
 548    _mesa_unmap_pbo_dest(ctx, pack);
 549    pipe_resource_reference(&dst, NULL);
 550    return;
 551
 552 fallback:
 553    _mesa_readpixels(ctx, x, y, width, height, format, type, pack, pixels);
 554 }
 555
 556 void st_init_readpixels_functions(struct dd_function_table *functions)
 557 {
 558    functions->ReadPixels = st_ReadPixels;
 559 }