src/mesa/drivers/dri/i965/intel_pixel_read.c

   1 /*
   2  * Copyright 2003 VMware, Inc.
   3  * All Rights Reserved.
   4  *
   5  * Permission is hereby granted, free of charge, to any person obtaining a
   6  * copy of this software and associated documentation files (the
   7  * "Software"), to deal in the Software without restriction, including
   8  * without limitation the rights to use, copy, modify, merge, publish,
   9  * distribute, sublicense, and/or sell copies of the Software, and to
  10  * permit persons to whom the Software is furnished to do so, subject to
  11  * the following conditions:
  12  *
  13  * The above copyright notice and this permission notice (including the
  14  * next paragraph) shall be included in all copies or substantial portions
  15  * of the Software.
  16  *
  17  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
  18  * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  19  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
  20  * IN NO EVENT SHALL VMWARE AND/OR ITS SUPPLIERS BE LIABLE FOR
  21  * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
  22  * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
  23  * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  24  */
  25
  26 #include "main/enums.h"
  27 #include "main/mtypes.h"
  28 #include "main/macros.h"
  29 #include "main/fbobject.h"
  30 #include "main/image.h"
  31 #include "main/bufferobj.h"
  32 #include "main/readpix.h"
  33 #include "main/state.h"
  34 #include "main/glformats.h"
  35 #include "program/prog_instruction.h"
  36 #include "drivers/common/meta.h"
  37
  38 #include "brw_context.h"
  39 #include "brw_blorp.h"
  40 #include "intel_screen.h"
  41 #include "intel_batchbuffer.h"
  42 #include "intel_blit.h"
  43 #include "intel_buffers.h"
  44 #include "intel_fbo.h"
  45 #include "intel_mipmap_tree.h"
  46 #include "intel_pixel.h"
  47 #include "intel_buffer_objects.h"
  48 #include "intel_tiled_memcpy.h"
  49
  50 #define FILE_DEBUG_FLAG DEBUG_PIXEL
  51
  52 /**
  53  * \brief A fast path for glReadPixels
  54  *
  55  * This fast path is taken when the source format is BGRA, RGBA,
  56  * A or L and when the texture memory is X- or Y-tiled.  It downloads
  57  * the source data by directly mapping the memory without a GTT fence.
  58  * This then needs to be de-tiled on the CPU before presenting the data to
  59  * the user in the linear fasion.
  60  *
  61  * This is a performance win over the conventional texture download path.
  62  * In the conventional texture download path, the texture is either mapped
  63  * through the GTT or copied to a linear buffer with the blitter before
  64  * handing off to a software path.  This allows us to avoid round-tripping
  65  * through the GPU (in the case where we would be blitting) and do only a
  66  * single copy operation.
  67  */
  68 static bool
  69 intel_readpixels_tiled_memcpy(struct gl_context * ctx,
  70                               GLint xoffset, GLint yoffset,
  71                               GLsizei width, GLsizei height,
  72                               GLenum format, GLenum type,
  73                               GLvoid * pixels,
  74                               const struct gl_pixelstore_attrib *pack)
  75 {
  76    struct brw_context *brw = brw_context(ctx);
  77    struct gl_renderbuffer *rb = ctx->ReadBuffer->_ColorReadBuffer;
  78    const struct gen_device_info *devinfo = &brw->screen->devinfo;
  79
  80    /* This path supports reading from color buffers only */
  81    if (rb == NULL)
  82       return false;
  83
  84    struct intel_renderbuffer *irb = intel_renderbuffer(rb);
  85    int dst_pitch;
  86
  87    /* The miptree's buffer. */
  88    struct brw_bo *bo;
  89
  90    uint32_t cpp;
  91    mem_copy_fn mem_copy = NULL;
  92
  93    /* This fastpath is restricted to specific renderbuffer types:
  94     * a 2D BGRA, RGBA, L8 or A8 texture. It could be generalized to support
  95     * more types.
  96     */
  97    if (!devinfo->has_llc ||
  98        !(type == GL_UNSIGNED_BYTE || type == GL_UNSIGNED_INT_8_8_8_8_REV) ||
  99        pixels == NULL ||
 100        _mesa_is_bufferobj(pack->BufferObj) ||
 101        pack->Alignment > 4 ||
 102        pack->SkipPixels > 0 ||
 103        pack->SkipRows > 0 ||
 104        (pack->RowLength != 0 && pack->RowLength != width) ||
 105        pack->SwapBytes ||
 106        pack->LsbFirst ||
 107        pack->Invert)
 108       return false;
 109
 110    /* Only a simple blit, no scale, bias or other mapping. */
 111    if (ctx->_ImageTransferState)
 112       return false;
 113
 114    /* It is possible that the renderbuffer (or underlying texture) is
 115     * multisampled.  Since ReadPixels from a multisampled buffer requires a
 116     * multisample resolve, we can't handle this here
 117     */
 118    if (rb->NumSamples > 1)
 119       return false;
 120
 121    /* We can't handle copying from RGBX or BGRX because the tiled_memcpy
 122     * function doesn't set the last channel to 1. Note this checks BaseFormat
 123     * rather than TexFormat in case the RGBX format is being simulated with an
 124     * RGBA format.
 125     */
 126    if (rb->_BaseFormat == GL_RGB)
 127       return false;
 128
 129    if (!intel_get_memcpy(rb->Format, format, type, &mem_copy, &cpp))
 130       return false;
 131
 132    if (!irb->mt ||
 133        (irb->mt->surf.tiling != ISL_TILING_X &&
 134         irb->mt->surf.tiling != ISL_TILING_Y0)) {
 135       /* The algorithm is written only for X- or Y-tiled memory. */
 136       return false;
 137    }
 138
 139    /* tiled_to_linear() assumes that if the object is swizzled, it is using
 140     * I915_BIT6_SWIZZLE_9_10 for X and I915_BIT6_SWIZZLE_9 for Y.  This is only
 141     * true on gen5 and above.
 142     *
 143     * The killer on top is that some gen4 have an L-shaped swizzle mode, where
 144     * parts of the memory aren't swizzled at all. Userspace just can't handle
 145     * that.
 146     */
 147    if (devinfo->gen < 5 && brw->has_swizzling)
 148       return false;
 149
 150    /* Since we are going to read raw data to the miptree, we need to resolve
 151     * any pending fast color clears before we start.
 152     */
 153    intel_miptree_access_raw(brw, irb->mt, irb->mt_level, irb->mt_layer, false);
 154
 155    bo = irb->mt->bo;
 156
 157    if (brw_batch_references(&brw->batch, bo)) {
 158       perf_debug("Flushing before mapping a referenced bo.\n");
 159       intel_batchbuffer_flush(brw);
 160    }
 161
 162    void *map = brw_bo_map(brw, bo, MAP_READ | MAP_RAW);
 163    if (map == NULL) {
 164       DBG("%s: failed to map bo\n", __func__);
 165       return false;
 166    }
 167
 168    unsigned slice_offset_x, slice_offset_y;
 169    intel_miptree_get_image_offset(irb->mt, irb->mt_level, irb->mt_layer,
 170                                   &slice_offset_x, &slice_offset_y);
 171    xoffset += slice_offset_x;
 172    yoffset += slice_offset_y;
 173
 174    dst_pitch = _mesa_image_row_stride(pack, width, format, type);
 175
 176    /* For a window-system renderbuffer, the buffer is actually flipped
 177     * vertically, so we need to handle that.  Since the detiling function
 178     * can only really work in the forwards direction, we have to be a
 179     * little creative.  First, we compute the Y-offset of the first row of
 180     * the renderbuffer (in renderbuffer coordinates).  We then match that
 181     * with the last row of the client's data.  Finally, we give
 182     * tiled_to_linear a negative pitch so that it walks through the
 183     * client's data backwards as it walks through the renderbufer forwards.
 184     */
 185    if (rb->Name == 0) {
 186       yoffset = rb->Height - yoffset - height;
 187       pixels += (ptrdiff_t) (height - 1) * dst_pitch;
 188       dst_pitch = -dst_pitch;
 189    }
 190
 191    /* We postponed printing this message until having committed to executing
 192     * the function.
 193     */
 194    DBG("%s: x,y=(%d,%d) (w,h)=(%d,%d) format=0x%x type=0x%x "
 195        "mesa_format=0x%x tiling=%d "
 196        "pack=(alignment=%d row_length=%d skip_pixels=%d skip_rows=%d)\n",
 197        __func__, xoffset, yoffset, width, height,
 198        format, type, rb->Format, irb->mt->surf.tiling,
 199        pack->Alignment, pack->RowLength, pack->SkipPixels,
 200        pack->SkipRows);
 201
 202    tiled_to_linear(
 203       xoffset * cpp, (xoffset + width) * cpp,
 204       yoffset, yoffset + height,
 205       pixels - (ptrdiff_t) yoffset * dst_pitch - (ptrdiff_t) xoffset * cpp,
 206       map + irb->mt->offset,
 207       dst_pitch, irb->mt->surf.row_pitch,
 208       brw->has_swizzling,
 209       irb->mt->surf.tiling,
 210       mem_copy
 211    );
 212
 213    brw_bo_unmap(bo);
 214    return true;
 215 }
 216
 217 static bool
 218 intel_readpixels_blorp(struct gl_context *ctx,
 219                        unsigned x, unsigned y,
 220                        unsigned w, unsigned h,
 221                        GLenum format, GLenum type, const void *pixels,
 222                        const struct gl_pixelstore_attrib *packing)
 223 {
 224    struct brw_context *brw = brw_context(ctx);
 225    struct gl_renderbuffer *rb = ctx->ReadBuffer->_ColorReadBuffer;
 226    if (!rb)
 227       return false;
 228
 229    struct intel_renderbuffer *irb = intel_renderbuffer(rb);
 230
 231    /* _mesa_get_readpixels_transfer_ops() includes the cases of read
 232     * color clamping along with the ctx->_ImageTransferState.
 233     */
 234    if (_mesa_get_readpixels_transfer_ops(ctx, rb->Format, format,
 235                                          type, GL_FALSE))
 236       return false;
 237
 238    GLenum dst_base_format = _mesa_unpack_format_to_base_format(format);
 239    if (_mesa_need_rgb_to_luminance_conversion(rb->_BaseFormat,
 240                                               dst_base_format))
 241       return false;
 242
 243    unsigned swizzle;
 244    if (irb->Base.Base._BaseFormat == GL_RGB) {
 245       swizzle = MAKE_SWIZZLE4(SWIZZLE_X, SWIZZLE_Y, SWIZZLE_Z, SWIZZLE_ONE);
 246    } else {
 247       swizzle = SWIZZLE_XYZW;
 248    }
 249
 250    return brw_blorp_download_miptree(brw, irb->mt, rb->Format, swizzle,
 251                                      irb->mt_level, x, y, irb->mt_layer,
 252                                      w, h, 1, GL_TEXTURE_2D, format, type,
 253                                      rb->Name == 0, pixels, packing);
 254 }
 255
 256 void
 257 intelReadPixels(struct gl_context * ctx,
 258                 GLint x, GLint y, GLsizei width, GLsizei height,
 259                 GLenum format, GLenum type,
 260                 const struct gl_pixelstore_attrib *pack, GLvoid * pixels)
 261 {
 262    bool ok;
 263
 264    struct brw_context *brw = brw_context(ctx);
 265    bool dirty;
 266
 267    DBG("%s\n", __func__);
 268
 269    /* Reading pixels wont dirty the front buffer, so reset the dirty
 270     * flag after calling intel_prepare_render().
 271     */
 272    dirty = brw->front_buffer_dirty;
 273    intel_prepare_render(brw);
 274    brw->front_buffer_dirty = dirty;
 275
 276    if (_mesa_is_bufferobj(pack->BufferObj)) {
 277       if (intel_readpixels_blorp(ctx, x, y, width, height,
 278                                  format, type, pixels, pack))
 279          return;
 280
 281       perf_debug("%s: fallback to CPU mapping in PBO case\n", __func__);
 282    }
 283
 284    ok = intel_readpixels_tiled_memcpy(ctx, x, y, width, height,
 285                                       format, type, pixels, pack);
 286    if(ok)
 287       return;
 288
 289    /* Update Mesa state before calling _mesa_readpixels().
 290     * XXX this may not be needed since ReadPixels no longer uses the
 291     * span code.
 292     */
 293
 294    if (ctx->NewState)
 295       _mesa_update_state(ctx);
 296
 297    _mesa_readpixels(ctx, x, y, width, height, format, type, pack, pixels);
 298
 299    /* There's an intel_prepare_render() call in intelSpanRenderStart(). */
 300    brw->front_buffer_dirty = dirty;
 301 }