/** * This uses a blit to copy the read buffer to a texture format which matches * the format and type combo and then a fast read-back is done using memcpy. * We can do arbitrary X/Y/Z/W/0/1 swizzling here as long as there is * a format which matches the swizzling. * * If such a format isn't available, we fall back to _mesa_readpixels. * * NOTE: Some drivers use a blit to convert between tiled and linear * texture layouts during texture uploads/downloads, so the blit * we do here should be free in such cases. */ static void st_readpixels(struct gl_context *ctx, GLint x, GLint y, GLsizei width, GLsizei height, GLenum format, GLenum type, const struct gl_pixelstore_attrib *pack, GLvoid *pixels) { struct st_context *st = st_context(ctx); struct gl_renderbuffer *rb = _mesa_get_read_renderbuffer_for_format(ctx, format); struct st_renderbuffer *strb = st_renderbuffer(rb); struct pipe_context *pipe = st->pipe; struct pipe_screen *screen = pipe->screen; struct pipe_resource *src; struct pipe_resource *dst = NULL; struct pipe_resource dst_templ; enum pipe_format dst_format, src_format; struct pipe_blit_info blit; unsigned bind = PIPE_BIND_TRANSFER_READ; struct pipe_transfer *tex_xfer; ubyte *map = NULL; /* Validate state (to be sure we have up-to-date framebuffer surfaces) * and flush the bitmap cache prior to reading. */ st_validate_state(st); st_flush_bitmap_cache(st); if (!st->prefer_blit_based_texture_transfer) { goto fallback; } /* This must be done after state validation. */ src = strb->texture; /* XXX Fallback for depth-stencil formats due to an incomplete * stencil blit implementation in some drivers. */ if (format == GL_DEPTH_STENCIL) { goto fallback; } /* We are creating a texture of the size of the region being read back. * Need to check for NPOT texture support. */ if (!screen->get_param(screen, PIPE_CAP_NPOT_TEXTURES) && (!util_is_power_of_two(width) || !util_is_power_of_two(height))) { goto fallback; } /* If the base internal format and the texture format don't match, we have * to use the slow path. */ if (rb->_BaseFormat != _mesa_get_format_base_format(rb->Format)) { goto fallback; } /* See if the texture format already matches the format and type, * in which case the memcpy-based fast path will likely be used and * we don't have to blit. */ if (_mesa_format_matches_format_and_type(rb->Format, format, type, pack->SwapBytes)) { goto fallback; } if (_mesa_readpixels_needs_slow_path(ctx, format, type, GL_TRUE)) { goto fallback; } /* Convert the source format to what is expected by ReadPixels * and see if it's supported. */ src_format = util_format_linear(src->format); src_format = util_format_luminance_to_red(src_format); src_format = util_format_intensity_to_red(src_format); if (!src_format || !screen->is_format_supported(screen, src_format, src->target, src->nr_samples, PIPE_BIND_SAMPLER_VIEW)) { goto fallback; } if (format == GL_DEPTH_COMPONENT || format == GL_DEPTH_STENCIL) bind |= PIPE_BIND_DEPTH_STENCIL; else bind |= PIPE_BIND_RENDER_TARGET; /* Choose the destination format by finding the best match * for the format+type combo. */ dst_format = st_choose_matching_format(screen, bind, format, type, pack->SwapBytes); if (dst_format == PIPE_FORMAT_NONE) { goto fallback; } /* create the destination texture */ memset(&dst_templ, 0, sizeof(dst_templ)); dst_templ.target = PIPE_TEXTURE_2D; dst_templ.format = dst_format; dst_templ.bind = bind; dst_templ.usage = PIPE_USAGE_STAGING; st_gl_texture_dims_to_pipe_dims(GL_TEXTURE_2D, width, height, 1, &dst_templ.width0, &dst_templ.height0, &dst_templ.depth0, &dst_templ.array_size); dst = screen->resource_create(screen, &dst_templ); if (!dst) { goto fallback; } memset(&blit, 0, sizeof(blit)); blit.src.resource = src; blit.src.level = strb->surface->u.tex.level; blit.src.format = src_format; blit.dst.resource = dst; blit.dst.level = 0; blit.dst.format = dst->format; blit.src.box.x = x; blit.dst.box.x = 0; blit.src.box.y = y; blit.dst.box.y = 0; blit.src.box.z = strb->surface->u.tex.first_layer; blit.dst.box.z = 0; blit.src.box.width = blit.dst.box.width = width; blit.src.box.height = blit.dst.box.height = height; blit.src.box.depth = blit.dst.box.depth = 1; blit.mask = st_get_blit_mask(rb->_BaseFormat, format); blit.filter = PIPE_TEX_FILTER_NEAREST; blit.scissor_enable = FALSE; if (st_fb_orientation(ctx->ReadBuffer) == Y_0_TOP) { blit.src.box.y = rb->Height - blit.src.box.y; blit.src.box.height = -blit.src.box.height; } /* blit */ st->pipe->blit(st->pipe, &blit); /* map resources */ pixels = _mesa_map_pbo_dest(ctx, pack, pixels); map = pipe_transfer_map_3d(pipe, dst, 0, PIPE_TRANSFER_READ, 0, 0, 0, width, height, 1, &tex_xfer); if (!map) { _mesa_unmap_pbo_dest(ctx, pack); pipe_resource_reference(&dst, NULL); goto fallback; } /* memcpy data into a user buffer */ { const uint bytesPerRow = width * util_format_get_blocksize(dst_format); GLuint row; for (row = 0; row < (unsigned) height; row++) { GLvoid *dest = _mesa_image_address3d(pack, pixels, width, height, format, type, 0, row, 0); memcpy(dest, map, bytesPerRow); map += tex_xfer->stride; } } pipe_transfer_unmap(pipe, tex_xfer); _mesa_unmap_pbo_dest(ctx, pack); pipe_resource_reference(&dst, NULL); return; fallback: _mesa_readpixels(ctx, x, y, width, height, format, type, pack, pixels); }
/** Linearize and convert luminace/intensity to red. */ enum pipe_format si_simplify_cb_format(enum pipe_format format) { format = util_format_linear(format); format = util_format_luminance_to_red(format); return util_format_intensity_to_red(format); }