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_buffers.h"
  43 #include "intel_fbo.h"
  44 #include "intel_mipmap_tree.h"
  45 #include "intel_pixel.h"
  46 #include "intel_buffer_objects.h"
  47
  48 #define FILE_DEBUG_FLAG DEBUG_PIXEL
  49
  50 /**
  51  * \brief A fast path for glReadPixels
  52  *
  53  * This fast path is taken when the source format is BGRA, RGBA,
  54  * A or L and when the texture memory is X- or Y-tiled.  It downloads
  55  * the source data by directly mapping the memory without a GTT fence.
  56  * This then needs to be de-tiled on the CPU before presenting the data to
  57  * the user in the linear fasion.
  58  *
  59  * This is a performance win over the conventional texture download path.
  60  * In the conventional texture download path, the texture is either mapped
  61  * through the GTT or copied to a linear buffer with the blitter before
  62  * handing off to a software path.  This allows us to avoid round-tripping
  63  * through the GPU (in the case where we would be blitting) and do only a
  64  * single copy operation.
  65  */
  66 static bool
  67 intel_readpixels_tiled_memcpy(struct gl_context * ctx,
  68                               GLint xoffset, GLint yoffset,
  69                               GLsizei width, GLsizei height,
  70                               GLenum format, GLenum type,
  71                               GLvoid * pixels,
  72                               const struct gl_pixelstore_attrib *pack)
  73 {
  74    struct brw_context *brw = brw_context(ctx);
  75    struct gl_renderbuffer *rb = ctx->ReadBuffer->_ColorReadBuffer;
  76    const struct gen_device_info *devinfo = &brw->screen->devinfo;
  77
  78    /* This path supports reading from color buffers only */
  79    if (rb == NULL)
  80       return false;
  81
  82    struct intel_renderbuffer *irb = intel_renderbuffer(rb);
  83    int dst_pitch;
  84
  85    /* The miptree's buffer. */
  86    struct brw_bo *bo;
  87
  88    uint32_t cpp;
  89    isl_memcpy_type copy_type;
  90
  91    /* This fastpath is restricted to specific renderbuffer types:
  92     * a 2D BGRA, RGBA, L8 or A8 texture. It could be generalized to support
  93     * more types.
  94     */
  95    if (!devinfo->has_llc ||
  96        !(type == GL_UNSIGNED_BYTE || type == GL_UNSIGNED_INT_8_8_8_8_REV) ||
  97        pixels == NULL ||
  98        pack->BufferObj ||
  99        pack->Alignment > 4 ||
 100        pack->SkipPixels > 0 ||
 101        pack->SkipRows > 0 ||
 102        (pack->RowLength != 0 && pack->RowLength != width) ||
 103        pack->SwapBytes ||
 104        pack->LsbFirst ||
 105        pack->Invert)
 106       return false;
 107
 108    /* Only a simple blit, no scale, bias or other mapping. */
 109    if (ctx->_ImageTransferState)
 110       return false;
 111
 112    /* It is possible that the renderbuffer (or underlying texture) is
 113     * multisampled.  Since ReadPixels from a multisampled buffer requires a
 114     * multisample resolve, we can't handle this here
 115     */
 116    if (rb->NumSamples > 1)
 117       return false;
 118
 119    /* We can't handle copying from RGBX or BGRX because the tiled_memcpy
 120     * function doesn't set the last channel to 1. Note this checks BaseFormat
 121     * rather than TexFormat in case the RGBX format is being simulated with an
 122     * RGBA format.
 123     */
 124    if (rb->_BaseFormat == GL_RGB)
 125       return false;
 126
 127    copy_type = intel_miptree_get_memcpy_type(rb->Format, format, type, &cpp);
 128    if (copy_type == ISL_MEMCPY_INVALID)
 129       return false;
 130
 131    if (!irb->mt ||
 132        (irb->mt->surf.tiling != ISL_TILING_X &&
 133         irb->mt->surf.tiling != ISL_TILING_Y0)) {
 134       /* The algorithm is written only for X- or Y-tiled memory. */
 135       return false;
 136    }
 137
 138    /* tiled_to_linear() assumes that if the object is swizzled, it is using
 139     * I915_BIT6_SWIZZLE_9_10 for X and I915_BIT6_SWIZZLE_9 for Y.  This is only
 140     * true on gen5 and above.
 141     *
 142     * The killer on top is that some gen4 have an L-shaped swizzle mode, where
 143     * parts of the memory aren't swizzled at all. Userspace just can't handle
 144     * that.
 145     */
 146    if (devinfo->gen < 5 && brw->has_swizzling)
 147       return false;
 148
 149    /* Since we are going to read raw data to the miptree, we need to resolve
 150     * any pending fast color clears before we start.
 151     */
 152    intel_miptree_access_raw(brw, irb->mt, irb->mt_level, irb->mt_layer, false);
 153
 154    bo = irb->mt->bo;
 155
 156    if (brw_batch_references(&brw->batch, bo)) {
 157       perf_debug("Flushing before mapping a referenced bo.\n");
 158       intel_batchbuffer_flush(brw);
 159    }
 160
 161    void *map = brw_bo_map(brw, bo, MAP_READ | MAP_RAW);
 162    if (map == NULL) {
 163       DBG("%s: failed to map bo\n", __func__);
 164       return false;
 165    }
 166
 167    unsigned slice_offset_x, slice_offset_y;
 168    intel_miptree_get_image_offset(irb->mt, irb->mt_level, irb->mt_layer,
 169                                   &slice_offset_x, &slice_offset_y);
 170    xoffset += slice_offset_x;
 171    yoffset += slice_offset_y;
 172
 173    dst_pitch = _mesa_image_row_stride(pack, width, format, type);
 174
 175    /* For a window-system renderbuffer, the buffer is actually flipped
 176     * vertically, so we need to handle that.  Since the detiling function
 177     * can only really work in the forwards direction, we have to be a
 178     * little creative.  First, we compute the Y-offset of the first row of
 179     * the renderbuffer (in renderbuffer coordinates).  We then match that
 180     * with the last row of the client's data.  Finally, we give
 181     * tiled_to_linear a negative pitch so that it walks through the
 182     * client's data backwards as it walks through the renderbufer forwards.
 183     */
 184    if (ctx->ReadBuffer->FlipY) {
 185       yoffset = rb->Height - yoffset - height;
 186       pixels += (ptrdiff_t) (height - 1) * dst_pitch;
 187       dst_pitch = -dst_pitch;
 188    }
 189
 190    /* We postponed printing this message until having committed to executing
 191     * the function.
 192     */
 193    DBG("%s: x,y=(%d,%d) (w,h)=(%d,%d) format=0x%x type=0x%x "
 194        "mesa_format=0x%x tiling=%d "
 195        "pack=(alignment=%d row_length=%d skip_pixels=%d skip_rows=%d)\n",
 196        __func__, xoffset, yoffset, width, height,
 197        format, type, rb->Format, irb->mt->surf.tiling,
 198        pack->Alignment, pack->RowLength, pack->SkipPixels,
 199        pack->SkipRows);
 200
 201    isl_memcpy_tiled_to_linear(
 202       xoffset * cpp, (xoffset + width) * cpp,
 203       yoffset, yoffset + height,
 204       pixels,
 205       map + irb->mt->offset,
 206       dst_pitch, irb->mt->surf.row_pitch_B,
 207       brw->has_swizzling,
 208       irb->mt->surf.tiling,
 209       copy_type
 210    );
 211
 212    brw_bo_unmap(bo);
 213    return true;
 214 }
 215
 216 static bool
 217 intel_readpixels_blorp(struct gl_context *ctx,
 218                        unsigned x, unsigned y,
 219                        unsigned w, unsigned h,
 220                        GLenum format, GLenum type, const void *pixels,
 221                        const struct gl_pixelstore_attrib *packing)
 222 {
 223    struct brw_context *brw = brw_context(ctx);
 224    struct gl_renderbuffer *rb = ctx->ReadBuffer->_ColorReadBuffer;
 225    if (!rb)
 226       return false;
 227
 228    struct intel_renderbuffer *irb = intel_renderbuffer(rb);
 229
 230    /* _mesa_get_readpixels_transfer_ops() includes the cases of read
 231     * color clamping along with the ctx->_ImageTransferState.
 232     */
 233    if (_mesa_get_readpixels_transfer_ops(ctx, rb->Format, format,
 234                                          type, GL_FALSE))
 235       return false;
 236
 237    GLenum dst_base_format = _mesa_unpack_format_to_base_format(format);
 238    if (_mesa_need_rgb_to_luminance_conversion(rb->_BaseFormat,
 239                                               dst_base_format))
 240       return false;
 241
 242    unsigned swizzle;
 243    if (irb->Base.Base._BaseFormat == GL_RGB) {
 244       swizzle = MAKE_SWIZZLE4(SWIZZLE_X, SWIZZLE_Y, SWIZZLE_Z, SWIZZLE_ONE);
 245    } else {
 246       swizzle = SWIZZLE_XYZW;
 247    }
 248
 249    return brw_blorp_download_miptree(brw, irb->mt, rb->Format, swizzle,
 250                                      irb->mt_level, x, y, irb->mt_layer,
 251                                      w, h, 1, GL_TEXTURE_2D, format, type,
 252                                      ctx->ReadBuffer->FlipY, pixels, packing);
 253 }
 254
 255 void
 256 intelReadPixels(struct gl_context * ctx,
 257                 GLint x, GLint y, GLsizei width, GLsizei height,
 258                 GLenum format, GLenum type,
 259                 const struct gl_pixelstore_attrib *pack, GLvoid * pixels)
 260 {
 261    bool ok;
 262
 263    struct brw_context *brw = brw_context(ctx);
 264    bool dirty;
 265
 266    DBG("%s\n", __func__);
 267
 268    /* Reading pixels wont dirty the front buffer, so reset the dirty
 269     * flag after calling intel_prepare_render().
 270     */
 271    dirty = brw->front_buffer_dirty;
 272    intel_prepare_render(brw);
 273    brw->front_buffer_dirty = dirty;
 274
 275    if (pack->BufferObj) {
 276       if (intel_readpixels_blorp(ctx, x, y, width, height,
 277                                  format, type, pixels, pack))
 278          return;
 279
 280       perf_debug("%s: fallback to CPU mapping in PBO case\n", __func__);
 281    }
 282
 283    ok = intel_readpixels_tiled_memcpy(ctx, x, y, width, height,
 284                                       format, type, pixels, pack);
 285    if(ok)
 286       return;
 287
 288    /* Update Mesa state before calling _mesa_readpixels().
 289     * XXX this may not be needed since ReadPixels no longer uses the
 290     * span code.
 291     */
 292
 293    if (ctx->NewState)
 294       _mesa_update_state(ctx);
 295
 296    _mesa_readpixels(ctx, x, y, width, height, format, type, pack, pixels);
 297
 298    /* There's an intel_prepare_render() call in intelSpanRenderStart(). */
 299    brw->front_buffer_dirty = dirty;
 300 }