diff --git a/Marlin/src/feature/bedlevel/ubl/ubl_motion.cpp b/Marlin/src/feature/bedlevel/ubl/ubl_motion.cpp index 8e8b5256d..ed9251010 100644 --- a/Marlin/src/feature/bedlevel/ubl/ubl_motion.cpp +++ b/Marlin/src/feature/bedlevel/ubl/ubl_motion.cpp @@ -75,19 +75,16 @@ debug_current_and_destination(PSTR("Start of ubl.line_to_destination_cartesian()")); } - if (cell_start_xi == cell_dest_xi && cell_start_yi == cell_dest_yi) { // if the whole move is within the same cell, - /** - * we don't need to break up the move - * - * If we are moving off the print bed, we are going to allow the move at this level. - * But we detect it and isolate it. For now, we just pass along the request. - */ + // A move within the same cell needs no splitting + if (cell_start_xi == cell_dest_xi && cell_start_yi == cell_dest_yi) { + // For a move off the bed, use a constant Z raise if (!WITHIN(cell_dest_xi, 0, GRID_MAX_POINTS_X - 1) || !WITHIN(cell_dest_yi, 0, GRID_MAX_POINTS_Y - 1)) { // Note: There is no Z Correction in this case. We are off the grid and don't know what // a reasonable correction would be. If the user has specified a UBL_Z_RAISE_WHEN_OFF_MESH // value, that will be used instead of a calculated (Bi-Linear interpolation) correction. + const float z_raise = 0.0 #ifdef UBL_Z_RAISE_WHEN_OFF_MESH + UBL_Z_RAISE_WHEN_OFF_MESH @@ -104,15 +101,7 @@ FINAL_MOVE: - /** - * Optimize some floating point operations here. We could call float get_z_correction(float x0, float y0) to - * generate the correction for us. But we can lighten the load on the CPU by doing a modified version of the function. - * We are going to only calculate the amount we are from the first mesh line towards the second mesh line once. - * We will use this fraction in both of the original two Z Height calculations for the bi-linear interpolation. And, - * instead of doing a generic divide of the distance, we know the distance is MESH_X_DIST so we can use the preprocessor - * to create a 1-over number for us. That will allow us to do a floating point multiply instead of a floating point divide. - */ - + // The distance is always MESH_X_DIST so multiply by the constant reciprocal. const float xratio = (end[X_AXIS] - mesh_index_to_xpos(cell_dest_xi)) * (1.0 / (MESH_X_DIST)); float z1 = z_values[cell_dest_xi ][cell_dest_yi ] + xratio * @@ -122,22 +111,13 @@ if (cell_dest_xi >= GRID_MAX_POINTS_X - 1) z1 = z2 = 0.0; - // we are done with the fractional X distance into the cell. Now with the two Z-Heights we have calculated, we - // are going to apply the Y-Distance into the cell to interpolate the final Z correction. + // X cell-fraction done. Interpolate the two Z offsets with the Y fraction for the final Z offset. + const float yratio = (end[Y_AXIS] - mesh_index_to_ypos(cell_dest_yi)) * (1.0 / (MESH_Y_DIST)), + z0 = cell_dest_yi < GRID_MAX_POINTS_Y - 1 ? (z1 + (z2 - z1) * yratio) * planner.fade_scaling_factor_for_z(end[Z_AXIS]) : 0.0; - const float yratio = (end[Y_AXIS] - mesh_index_to_ypos(cell_dest_yi)) * (1.0 / (MESH_Y_DIST)); - float z0 = cell_dest_yi < GRID_MAX_POINTS_Y - 1 ? (z1 + (z2 - z1) * yratio) * planner.fade_scaling_factor_for_z(end[Z_AXIS]) : 0.0; - - /** - * If part of the Mesh is undefined, it will show up as NAN - * in z_values[][] and propagate through the - * calculations. If our correction is NAN, we throw it out - * because part of the Mesh is undefined and we don't have the - * information we need to complete the height correction. - */ - if (isnan(z0)) z0 = 0.0; - - planner.buffer_segment(end[X_AXIS], end[Y_AXIS], end[Z_AXIS] + z0, end[E_AXIS], feed_rate, extruder); + // Undefined parts of the Mesh in z_values[][] are NAN. + // Replace NAN corrections with 0.0 to prevent NAN propagation. + planner.buffer_segment(end[X_AXIS], end[Y_AXIS], end[Z_AXIS] + (isnan(z0) ? 0.0 : z0), end[E_AXIS], feed_rate, extruder); if (g26_debug_flag) debug_current_and_destination(PSTR("FINAL_MOVE in ubl.line_to_destination_cartesian()")); @@ -147,11 +127,8 @@ } /** - * If we get here, we are processing a move that crosses at least one Mesh Line. We will check - * for the simple case of just crossing X or just crossing Y Mesh Lines after we get all the details - * of the move figured out. We can process the easy case of just crossing an X or Y Mesh Line with less - * computation and in fact most lines are of this nature. We will check for that in the following - * blocks of code: + * Past this point the move is known to cross one or more mesh lines. Check for the most common + * case - crossing only one X or Y line - after details are worked out to reduce computation. */ const float dx = end[X_AXIS] - start[X_AXIS], @@ -167,12 +144,11 @@ dyi = cell_start_yi == cell_dest_yi ? 0 : down_flag ? -1 : 1; /** - * Compute the scaling factor for the extruder for each partial move. - * We need to watch out for zero length moves because it will cause us to - * have an infinate scaling factor. We are stuck doing a floating point - * divide to get our scaling factor, but after that, we just multiply by this - * number. We also pick our scaling factor based on whether the X or Y - * component is larger. We use the biggest of the two to preserve precision. + * Compute the extruder scaling factor for each partial move, checking for + * zero-length moves that would result in an infinite scaling factor. + * A float divide is required for this, but then it just multiplies. + * Also select a scaling factor based on the larger of the X and Y + * components. The larger of the two is used to preserve precision. */ const bool use_x_dist = adx > ady; @@ -192,43 +168,37 @@ const bool inf_normalized_flag = (isinf(e_normalized_dist) != 0), inf_m_flag = (isinf(m) != 0); + /** - * This block handles vertical lines. These are lines that stay within the same - * X Cell column. They do not need to be perfectly vertical. They just can - * not cross into another X Cell column. + * Handle vertical lines that stay within one column. + * These need not be perfectly vertical. */ - if (dxi == 0) { // Check for a vertical line - current_yi += down_flag; // Line is heading down, we just want to go to the bottom + if (dxi == 0) { // Vertical line? + current_yi += down_flag; // Line going down? Just go to the bottom. while (current_yi != cell_dest_yi + down_flag) { current_yi += dyi; const float next_mesh_line_y = mesh_index_to_ypos(current_yi); /** - * if the slope of the line is infinite, we won't do the calculations - * else, we know the next X is the same so we can recover and continue! - * Calculate X at the next Y mesh line + * Skip the calculations for an infinite slope. + * For others the next X is the same so this can continue. + * Calculate X at the next Y mesh line. */ const float rx = inf_m_flag ? start[X_AXIS] : (next_mesh_line_y - c) / m; float z0 = z_correction_for_x_on_horizontal_mesh_line(rx, current_xi, current_yi) * planner.fade_scaling_factor_for_z(end[Z_AXIS]); - /** - * If part of the Mesh is undefined, it will show up as NAN - * in z_values[][] and propagate through the - * calculations. If our correction is NAN, we throw it out - * because part of the Mesh is undefined and we don't have the - * information we need to complete the height correction. - */ + // Undefined parts of the Mesh in z_values[][] are NAN. + // Replace NAN corrections with 0.0 to prevent NAN propagation. if (isnan(z0)) z0 = 0.0; const float ry = mesh_index_to_ypos(current_yi); /** - * Without this check, it is possible for the algorithm to generate a zero length move in the case - * where the line is heading down and it is starting right on a Mesh Line boundary. For how often that - * happens, it might be best to remove the check and always 'schedule' the move because - * the planner.buffer_segment() routine will filter it if that happens. + * Without this check, it's possible to generate a zero length move, as in the case where + * the line is heading down, starting exactly on a mesh line boundary. Since this is rare + * it might be fine to remove this check and let planner.buffer_segment() filter it out. */ if (ry != start[Y_AXIS]) { if (!inf_normalized_flag) { @@ -248,9 +218,7 @@ if (g26_debug_flag) debug_current_and_destination(PSTR("vertical move done in ubl.line_to_destination_cartesian()")); - // - // Check if we are at the final destination. Usually, we won't be, but if it is on a Y Mesh Line, we are done. - // + // At the final destination? Usually not, but when on a Y Mesh Line it's completed. if (current_position[X_AXIS] != end[X_AXIS] || current_position[Y_AXIS] != end[Y_AXIS]) goto FINAL_MOVE; @@ -259,16 +227,11 @@ } /** - * - * This block handles horizontal lines. These are lines that stay within the same - * Y Cell row. They do not need to be perfectly horizontal. They just can - * not cross into another Y Cell row. - * + * Handle horizontal lines that stay within one row. + * These need not be perfectly horizontal. */ - - if (dyi == 0) { // Check for a horizontal line - current_xi += left_flag; // Line is heading left, we just want to go to the left - // edge of this cell for the first move. + if (dyi == 0) { // Horizontal line? + current_xi += left_flag; // Heading left? Just go to the left edge of the cell for the first move. while (current_xi != cell_dest_xi + left_flag) { current_xi += dxi; const float next_mesh_line_x = mesh_index_to_xpos(current_xi), @@ -277,22 +240,16 @@ float z0 = z_correction_for_y_on_vertical_mesh_line(ry, current_xi, current_yi) * planner.fade_scaling_factor_for_z(end[Z_AXIS]); - /** - * If part of the Mesh is undefined, it will show up as NAN - * in z_values[][] and propagate through the - * calculations. If our correction is NAN, we throw it out - * because part of the Mesh is undefined and we don't have the - * information we need to complete the height correction. - */ + // Undefined parts of the Mesh in z_values[][] are NAN. + // Replace NAN corrections with 0.0 to prevent NAN propagation. if (isnan(z0)) z0 = 0.0; const float rx = mesh_index_to_xpos(current_xi); /** - * Without this check, it is possible for the algorithm to generate a zero length move in the case - * where the line is heading left and it is starting right on a Mesh Line boundary. For how often - * that happens, it might be best to remove the check and always 'schedule' the move because - * the planner.buffer_segment() routine will filter it if that happens. + * Without this check, it's possible to generate a zero length move, as in the case where + * the line is heading left, starting exactly on a mesh line boundary. Since this is rare + * it might be fine to remove this check and let planner.buffer_segment() filter it out. */ if (rx != start[X_AXIS]) { if (!inf_normalized_flag) { @@ -321,7 +278,7 @@ /** * - * This block handles the generic case of a line crossing both X and Y Mesh lines. + * Handle the generic case of a line crossing both X and Y Mesh lines. * */ @@ -334,7 +291,7 @@ current_xi += left_flag; current_yi += down_flag; - while (xi_cnt > 0 || yi_cnt > 0) { + while (xi_cnt || yi_cnt) { const float next_mesh_line_x = mesh_index_to_xpos(current_xi + dxi), next_mesh_line_y = mesh_index_to_ypos(current_yi + dyi), @@ -349,13 +306,8 @@ float z0 = z_correction_for_x_on_horizontal_mesh_line(rx, current_xi - left_flag, current_yi + dyi) * planner.fade_scaling_factor_for_z(end[Z_AXIS]); - /** - * If part of the Mesh is undefined, it will show up as NAN - * in z_values[][] and propagate through the - * calculations. If our correction is NAN, we throw it out - * because part of the Mesh is undefined and we don't have the - * information we need to complete the height correction. - */ + // Undefined parts of the Mesh in z_values[][] are NAN. + // Replace NAN corrections with 0.0 to prevent NAN propagation. if (isnan(z0)) z0 = 0.0; if (!inf_normalized_flag) { @@ -376,13 +328,8 @@ float z0 = z_correction_for_y_on_vertical_mesh_line(ry, current_xi + dxi, current_yi - down_flag) * planner.fade_scaling_factor_for_z(end[Z_AXIS]); - /** - * If part of the Mesh is undefined, it will show up as NAN - * in z_values[][] and propagate through the - * calculations. If our correction is NAN, we throw it out - * because part of the Mesh is undefined and we don't have the - * information we need to complete the height correction. - */ + // Undefined parts of the Mesh in z_values[][] are NAN. + // Replace NAN corrections with 0.0 to prevent NAN propagation. if (isnan(z0)) z0 = 0.0; if (!inf_normalized_flag) { @@ -400,7 +347,7 @@ xi_cnt--; } - if (xi_cnt < 0 || yi_cnt < 0) break; // we've gone too far, so exit the loop and move on to FINAL_MOVE + //if (xi_cnt < 0 || yi_cnt < 0) break; // Too far! Exit the loop and go to FINAL_MOVE } if (g26_debug_flag)