+/**
+ * Helper for intel_miptree_alloc_hiz() that determines the required hiz
+ * buffer dimensions and allocates a bo for the hiz buffer.
+ */
+static struct intel_miptree_aux_buffer *
+intel_gen7_hiz_buf_create(struct brw_context *brw,
+ struct intel_mipmap_tree *mt)
+{
+ unsigned z_width = mt->logical_width0;
+ unsigned z_height = mt->logical_height0;
+ const unsigned z_depth = MAX2(mt->logical_depth0, 1);
+ unsigned hz_width, hz_height;
+ struct intel_miptree_aux_buffer *buf = calloc(sizeof(*buf), 1);
+
+ if (!buf)
+ return NULL;
+
+ /* Gen7 PRM Volume 2, Part 1, 11.5.3 "Hierarchical Depth Buffer" documents
+ * adjustments required for Z_Height and Z_Width based on multisampling.
+ */
+ switch (mt->num_samples) {
+ case 0:
+ case 1:
+ break;
+ case 2:
+ case 4:
+ z_width *= 2;
+ z_height *= 2;
+ break;
+ case 8:
+ z_width *= 4;
+ z_height *= 2;
+ break;
+ default:
+ unreachable("unsupported sample count");
+ }
+
+ const unsigned vertical_align = 8; /* 'j' in the docs */
+ const unsigned H0 = z_height;
+ const unsigned h0 = ALIGN(H0, vertical_align);
+ const unsigned h1 = ALIGN(minify(H0, 1), vertical_align);
+ const unsigned Z0 = z_depth;
+
+ /* HZ_Width (bytes) = ceiling(Z_Width / 16) * 16 */
+ hz_width = ALIGN(z_width, 16);
+
+ if (mt->target == GL_TEXTURE_3D) {
+ unsigned H_i = H0;
+ unsigned Z_i = Z0;
+ hz_height = 0;
+ for (int level = mt->first_level; level <= mt->last_level; ++level) {
+ unsigned h_i = ALIGN(H_i, vertical_align);
+ /* sum(i=0 to m; h_i * max(1, floor(Z_Depth/2**i))) */
+ hz_height += h_i * Z_i;
+ H_i = minify(H_i, 1);
+ Z_i = minify(Z_i, 1);
+ }
+ /* HZ_Height =
+ * (1/2) * sum(i=0 to m; h_i * max(1, floor(Z_Depth/2**i)))
+ */
+ hz_height = DIV_ROUND_UP(hz_height, 2);
+ } else {
+ const unsigned hz_qpitch = h0 + h1 + (12 * vertical_align);
+ if (mt->target == GL_TEXTURE_CUBE_MAP_ARRAY ||
+ mt->target == GL_TEXTURE_CUBE_MAP) {
+ /* HZ_Height (rows) = Ceiling ( ( Q_pitch * Z_depth * 6/2) /8 ) * 8 */
+ hz_height = DIV_ROUND_UP(hz_qpitch * Z0 * 6, 2 * 8) * 8;
+ } else {
+ /* HZ_Height (rows) = Ceiling ( ( Q_pitch * Z_depth/2) /8 ) * 8 */
+ hz_height = DIV_ROUND_UP(hz_qpitch * Z0, 2 * 8) * 8;
+ }
+ }
+
+ unsigned long pitch;
+ uint32_t tiling = I915_TILING_Y;
+ buf->bo = drm_intel_bo_alloc_tiled(brw->bufmgr, "hiz",
+ hz_width, hz_height, 1,
+ &tiling, &pitch,
+ BO_ALLOC_FOR_RENDER);
+ if (!buf->bo) {
+ free(buf);
+ return NULL;
+ } else if (tiling != I915_TILING_Y) {
+ drm_intel_bo_unreference(buf->bo);
+ free(buf);
+ return NULL;
+ }
+
+ buf->pitch = pitch;
+
+ return buf;
+}
+
+
+/**
+ * Helper for intel_miptree_alloc_hiz() that determines the required hiz
+ * buffer dimensions and allocates a bo for the hiz buffer.
+ */
+static struct intel_miptree_aux_buffer *
+intel_gen8_hiz_buf_create(struct brw_context *brw,
+ struct intel_mipmap_tree *mt)
+{
+ unsigned z_width = mt->logical_width0;
+ unsigned z_height = mt->logical_height0;
+ const unsigned z_depth = MAX2(mt->logical_depth0, 1);
+ unsigned hz_width, hz_height;
+ struct intel_miptree_aux_buffer *buf = calloc(sizeof(*buf), 1);
+
+ if (!buf)
+ return NULL;
+
+ /* Gen7 PRM Volume 2, Part 1, 11.5.3 "Hierarchical Depth Buffer" documents
+ * adjustments required for Z_Height and Z_Width based on multisampling.
+ */
+ switch (mt->num_samples) {
+ case 0:
+ case 1:
+ break;
+ case 2:
+ case 4:
+ z_width *= 2;
+ z_height *= 2;
+ break;
+ case 8:
+ z_width *= 4;
+ z_height *= 2;
+ break;
+ default:
+ unreachable("unsupported sample count");
+ }
+
+ const unsigned vertical_align = 8; /* 'j' in the docs */
+ const unsigned H0 = z_height;
+ const unsigned h0 = ALIGN(H0, vertical_align);
+ const unsigned h1 = ALIGN(minify(H0, 1), vertical_align);
+ const unsigned Z0 = z_depth;
+
+ /* HZ_Width (bytes) = ceiling(Z_Width / 16) * 16 */
+ hz_width = ALIGN(z_width, 16);
+
+ unsigned H_i = H0;
+ unsigned Z_i = Z0;
+ unsigned sum_h_i = 0;
+ unsigned hz_height_3d_sum = 0;
+ for (int level = mt->first_level; level <= mt->last_level; ++level) {
+ unsigned i = level - mt->first_level;
+ unsigned h_i = ALIGN(H_i, vertical_align);
+ /* sum(i=2 to m; h_i) */
+ if (i >= 2) {
+ sum_h_i += h_i;
+ }
+ /* sum(i=0 to m; h_i * max(1, floor(Z_Depth/2**i))) */
+ hz_height_3d_sum += h_i * Z_i;
+ H_i = minify(H_i, 1);
+ Z_i = minify(Z_i, 1);
+ }
+ /* HZ_QPitch = h0 + max(h1, sum(i=2 to m; h_i)) */
+ buf->qpitch = h0 + MAX2(h1, sum_h_i);
+
+ if (mt->target == GL_TEXTURE_3D) {
+ /* (1/2) * sum(i=0 to m; h_i * max(1, floor(Z_Depth/2**i))) */
+ hz_height = DIV_ROUND_UP(hz_height_3d_sum, 2);
+ } else {
+ /* HZ_Height (rows) = ceiling( (HZ_QPitch/2)/8) *8 * Z_Depth */
+ hz_height = DIV_ROUND_UP(buf->qpitch, 2 * 8) * 8 * Z0;
+ if (mt->target == GL_TEXTURE_CUBE_MAP_ARRAY ||
+ mt->target == GL_TEXTURE_CUBE_MAP) {
+ /* HZ_Height (rows) = ceiling( (HZ_QPitch/2)/8) *8 * 6 * Z_Depth
+ *
+ * We can can just take our hz_height calculation from above, and
+ * multiply by 6 for the cube map and cube map array types.
+ */
+ hz_height *= 6;
+ }
+ }
+
+ unsigned long pitch;
+ uint32_t tiling = I915_TILING_Y;
+ buf->bo = drm_intel_bo_alloc_tiled(brw->bufmgr, "hiz",
+ hz_width, hz_height, 1,
+ &tiling, &pitch,
+ BO_ALLOC_FOR_RENDER);
+ if (!buf->bo) {
+ free(buf);
+ return NULL;
+ } else if (tiling != I915_TILING_Y) {
+ drm_intel_bo_unreference(buf->bo);
+ free(buf);
+ return NULL;
+ }
+
+ buf->pitch = pitch;
+
+ return buf;
+}
+
+
+static struct intel_miptree_aux_buffer *
+intel_hiz_miptree_buf_create(struct brw_context *brw,
+ struct intel_mipmap_tree *mt)
+{
+ struct intel_miptree_aux_buffer *buf = calloc(sizeof(*buf), 1);
+ const bool force_all_slices_at_each_lod = brw->gen == 6;
+
+ if (!buf)
+ return NULL;
+
+ buf->mt = intel_miptree_create(brw,
+ mt->target,
+ mt->format,
+ mt->first_level,
+ mt->last_level,
+ mt->logical_width0,
+ mt->logical_height0,
+ mt->logical_depth0,
+ true,
+ mt->num_samples,
+ INTEL_MIPTREE_TILING_ANY,
+ force_all_slices_at_each_lod);
+ if (!buf->mt) {
+ free(buf);
+ return NULL;
+ }
+
+ buf->bo = buf->mt->bo;
+ buf->pitch = buf->mt->pitch;
+ buf->qpitch = buf->mt->qpitch;
+
+ return buf;
+}
+
+bool
+intel_miptree_wants_hiz_buffer(struct brw_context *brw,
+ struct intel_mipmap_tree *mt)
+{
+ if (!brw->has_hiz)
+ return false;
+
+ if (mt->hiz_buf != NULL)
+ return false;
+
+ if (mt->disable_aux_buffers)
+ return false;
+
+ switch (mt->format) {
+ case MESA_FORMAT_Z_FLOAT32:
+ case MESA_FORMAT_Z32_FLOAT_S8X24_UINT:
+ case MESA_FORMAT_Z24_UNORM_X8_UINT:
+ case MESA_FORMAT_Z24_UNORM_S8_UINT:
+ case MESA_FORMAT_Z_UNORM16:
+ return true;
+ default:
+ return false;
+ }
+}