Voxel Remesh: Edit Voxel Size operator

This operator lets the user control the voxel/detail size of the voxel remesher directly from the 3D view in a similar way the Brush radius and strength are controlled.  The shorcut from sculpt mode is Shift + R (similar to Shift + F for brush strength).
It shows a grid that represents the real voxel size of the object. The grid and the text are automatically aligned to the view to avoid rendering all voxels with thousands of lines.

It also has a slow mode when pressing shift that works like the slow mode of the brush radius control.

This operator controls the value changes sensitivity automatically to avoid jumping to extremelly high resolutions and run out of memory.
This way, adjusments done in lower voxel sizes are more precise. Pressing Ctrl disables this functionality and allows changing the voxel size directly in a linear way.

Reviewed By: jbakker, #user_interface, billreynish

Differential Revision: https://developer.blender.org/D6449

release/scripts/presets/keyconfig/keymap_data/blender_default.py

@@ -4323,6 +4323,7 @@ def km_sculpt(params):
         ("sculpt.set_detail_size", {"type": 'D', "value": 'PRESS', "shift": True}, None),
         # Remesh
         ("object.voxel_remesh", {"type": 'R', "value": 'PRESS', "ctrl": True}, None),
+        ("object.voxel_size_edit", {"type": 'R', "value": 'PRESS', "shift": True}, None),
         ("object.quadriflow_remesh", {"type": 'R', "value": 'PRESS', "ctrl": True, "alt": True}, None),
         # Brush properties
         ("brush.scale_size", {"type": 'LEFT_BRACKET', "value": 'PRESS'},

source/blender/editors/object/CMakeLists.txt

@@ -18,6 +18,7 @@
 set(INC
   ../include
   ../../blenkernel
+  ../../blenfont
   ../../blenlib
   ../../blentranslation
   ../../bmesh

source/blender/editors/object/object_intern.h

@@ -291,6 +291,7 @@ void TRANSFORM_OT_vertex_random(struct wmOperatorType *ot);
 
 /* object_remesh.c */
 void OBJECT_OT_voxel_remesh(struct wmOperatorType *ot);
+void OBJECT_OT_voxel_size_edit(struct wmOperatorType *ot);
 void OBJECT_OT_quadriflow_remesh(struct wmOperatorType *ot);
 
 /* object_transfer_data.c */

source/blender/editors/object/object_ops.c

@@ -265,6 +265,8 @@ void ED_operatortypes_object(void)
   WM_operatortype_append(OBJECT_OT_hide_collection);
 
   WM_operatortype_append(OBJECT_OT_voxel_remesh);
+  WM_operatortype_append(OBJECT_OT_voxel_size_edit);
+
   WM_operatortype_append(OBJECT_OT_quadriflow_remesh);
 }
 

source/blender/editors/object/object_remesh.c

@@ -37,6 +37,9 @@
 #include "DNA_meshdata_types.h"
 #include "DNA_object_types.h"
 #include "DNA_scene_types.h"
+#include "DNA_userdef_types.h"
+
+#include "BLT_translation.h"
 
 #include "BKE_context.h"
 #include "BKE_customdata.h"
@@ -61,17 +64,29 @@
 #include "ED_object.h"
 #include "ED_screen.h"
 #include "ED_sculpt.h"
+#include "ED_space_api.h"
 #include "ED_undo.h"
+#include "ED_view3d.h"
 
 #include "RNA_access.h"
 #include "RNA_define.h"
 #include "RNA_enum_types.h"
 
+#include "GPU_draw.h"
+#include "GPU_immediate.h"
+#include "GPU_immediate_util.h"
+#include "GPU_matrix.h"
+#include "GPU_state.h"
+
 #include "WM_api.h"
 #include "WM_message.h"
 #include "WM_toolsystem.h"
 #include "WM_types.h"
 
+#include "UI_interface.h"
+
+#include "BLF_api.h"
+
 #include "object_intern.h"  // own include
 
 /* TODO(sebpa): unstable, can lead to unrecoverable errors. */
@@ -188,16 +203,403 @@ void OBJECT_OT_voxel_remesh(wmOperatorType *ot)
   ot->flag = OPTYPE_REGISTER | OPTYPE_UNDO;
 }
 
+#define VOXEL_SIZE_EDIT_MAX_GRIDS_LINES 500
+#define VOXEL_SIZE_EDIT_MAX_STR_LEN 20
+
+typedef struct VoxelSizeEditCustomData {
+  void *draw_handle;
+  Object *active_object;
+
+  float init_mval[2];
+  float slow_mval[2];
+
+  bool slow_mode;
+
+  float init_voxel_size;
+  float slow_voxel_size;
+  float voxel_size;
+
+  float preview_plane[4][3];
+
+  float text_mat[4][4];
+} VoxelSizeEditCustomData;
+
+static void voxel_size_parallel_lines_draw(uint pos3d,
+                                           const float initial_co[3],
+                                           const float end_co[3],
+                                           const float length_co[3],
+                                           const float spacing)
+{
+  const float total_len = len_v3v3(initial_co, end_co);
+  const int tot_lines = (int)(total_len / spacing);
+  const int tot_lines_half = (tot_lines / 2) + 1;
+  float spacing_dir[3], lines_start[3];
+  float line_dir[3];
+  sub_v3_v3v3(spacing_dir, end_co, initial_co);
+  normalize_v3(spacing_dir);
+
+  sub_v3_v3v3(line_dir, length_co, initial_co);
+
+  if (tot_lines > VOXEL_SIZE_EDIT_MAX_GRIDS_LINES || tot_lines <= 1) {
+    return;
+  }
+
+  mid_v3_v3v3(lines_start, initial_co, end_co);
+
+  immBegin(GPU_PRIM_LINES, (uint)tot_lines_half * 2);
+  for (int i = 0; i < tot_lines_half; i++) {
+    float line_start[3];
+    float line_end[3];
+    madd_v3_v3v3fl(line_start, lines_start, spacing_dir, spacing * i);
+    add_v3_v3v3(line_end, line_start, line_dir);
+    immVertex3fv(pos3d, line_start);
+    immVertex3fv(pos3d, line_end);
+  }
+  immEnd();
+
+  mul_v3_fl(spacing_dir, -1.0f);
+
+  immBegin(GPU_PRIM_LINES, (uint)(tot_lines_half - 1) * 2);
+  for (int i = 1; i < tot_lines_half; i++) {
+    float line_start[3];
+    float line_end[3];
+    madd_v3_v3v3fl(line_start, lines_start, spacing_dir, spacing * i);
+    add_v3_v3v3(line_end, line_start, line_dir);
+    immVertex3fv(pos3d, line_start);
+    immVertex3fv(pos3d, line_end);
+  }
+  immEnd();
+}
+
+static void voxel_size_edit_draw(const bContext *UNUSED(C), ARegion *UNUSED(ar), void *arg)
+{
+  VoxelSizeEditCustomData *cd = arg;
+
+  GPU_blend(true);
+  GPU_line_smooth(true);
+
+  uint pos3d = GPU_vertformat_attr_add(immVertexFormat(), "pos", GPU_COMP_F32, 3, GPU_FETCH_FLOAT);
+  immBindBuiltinProgram(GPU_SHADER_3D_UNIFORM_COLOR);
+  GPU_matrix_push();
+  GPU_matrix_mul(cd->active_object->obmat);
+
+  /* Draw Rect */
+  immUniformColor4f(0.9f, 0.9f, 0.9f, 0.8f);
+  GPU_line_width(3.0f);
+
+  immBegin(GPU_PRIM_LINES, 8);
+  immVertex3fv(pos3d, cd->preview_plane[0]);
+  immVertex3fv(pos3d, cd->preview_plane[1]);
+
+  immVertex3fv(pos3d, cd->preview_plane[1]);
+  immVertex3fv(pos3d, cd->preview_plane[2]);
+
+  immVertex3fv(pos3d, cd->preview_plane[2]);
+  immVertex3fv(pos3d, cd->preview_plane[3]);
+
+  immVertex3fv(pos3d, cd->preview_plane[3]);
+  immVertex3fv(pos3d, cd->preview_plane[0]);
+  immEnd();
+
+  /* Draw Grid */
+  GPU_line_width(1.0f);
+
+  const float total_len = len_v3v3(cd->preview_plane[0], cd->preview_plane[1]);
+  const int tot_lines = (int)(total_len / cd->voxel_size);
+
+  /* Smoothstep to reduce the alpha of the grid as the line number increases. */
+  const float a = VOXEL_SIZE_EDIT_MAX_GRIDS_LINES * 0.1f;
+  const float b = VOXEL_SIZE_EDIT_MAX_GRIDS_LINES;
+  const float x = clamp_f((tot_lines - a) / (b - a), 0.0f, 1.0);
+  const float alpha_factor = 1.0f - (x * x * (3.0f - 2.0f * x));
+
+  immUniformColor4f(0.9f, 0.9f, 0.9f, 0.75f * alpha_factor);
+  voxel_size_parallel_lines_draw(
+      pos3d, cd->preview_plane[0], cd->preview_plane[1], cd->preview_plane[3], cd->voxel_size);
+  voxel_size_parallel_lines_draw(
+      pos3d, cd->preview_plane[1], cd->preview_plane[2], cd->preview_plane[0], cd->voxel_size);
+
+  /* Draw text */
+  uiStyle *style = UI_style_get();
+  const uiFontStyle *fstyle = &style->widget;
+  const int fontid = fstyle->uifont_id;
+  float strwidth, strheight;
+  short fstyle_points = fstyle->points;
+  char str[VOXEL_SIZE_EDIT_MAX_STR_LEN];
+  short strdrawlen = 0;
+
+  BLI_snprintf(str, VOXEL_SIZE_EDIT_MAX_STR_LEN, "%3.4f%%", cd->voxel_size);
+  strdrawlen = BLI_strlen_utf8(str);
+
+  immUnbindProgram();
+
+  GPU_matrix_push();
+  GPU_matrix_mul(cd->text_mat);
+  BLF_size(fontid, 10.0f * fstyle_points, U.dpi);
+  BLF_color3f(fontid, 1.0f, 1.0f, 1.0f);
+  BLF_width_and_height(fontid, str, strdrawlen, &strwidth, &strheight);
+  BLF_position(fontid, -0.5f * strwidth, -0.5f * strheight, 0.0f);
+  BLF_draw(fontid, str, strdrawlen);
+  GPU_matrix_pop();
+
+  GPU_matrix_pop();
+
+  GPU_blend(false);
+  GPU_line_smooth(false);
+}
+
+static void voxel_size_edit_cancel(bContext *C, wmOperator *op)
+{
+  ARegion *ar = CTX_wm_region(C);
+  VoxelSizeEditCustomData *cd = op->customdata;
+
+  ED_region_draw_cb_exit(ar->type, cd->draw_handle);
+
+  MEM_freeN(op->customdata);
+
+  ED_workspace_status_text(C, NULL);
+}
+
+static int voxel_size_edit_modal(bContext *C, wmOperator *op, const wmEvent *event)
+{
+  ARegion *ar = CTX_wm_region(C);
+  VoxelSizeEditCustomData *cd = op->customdata;
+  Object *active_object = cd->active_object;
+  Mesh *mesh = (Mesh *)active_object->data;
+
+  /* Cancel modal operator */
+  if ((event->type == EVT_ESCKEY && event->val == KM_PRESS) ||
+      (event->type == RIGHTMOUSE && event->val == KM_PRESS)) {
+    voxel_size_edit_cancel(C, op);
+    ED_region_tag_redraw(ar);
+    return OPERATOR_FINISHED;
+  }
+
+  /* Finish modal operator */
+  if ((event->type == LEFTMOUSE && event->val == KM_RELEASE) ||
+      (event->type == EVT_RETKEY && event->val == KM_PRESS) ||
+      (event->type == EVT_PADENTER && event->val == KM_PRESS)) {
+    ED_region_draw_cb_exit(ar->type, cd->draw_handle);
+    mesh->remesh_voxel_size = cd->voxel_size;
+    MEM_freeN(op->customdata);
+    ED_region_tag_redraw(ar);
+    return OPERATOR_FINISHED;
+  }
+
+  float mval[2] = {event->mval[0], event->mval[1]};
+
+  float d = cd->init_mval[0] - mval[0];
+
+  if (cd->slow_mode) {
+    d = cd->slow_mval[0] - mval[0];
+  }
+
+  if (event->ctrl) {
+    /* Linear mode, enables jumping to any voxel size. */
+    d = d * 0.0005f;
+  }
+  else {
+    /* Multiply d by the initial voxel size to prevent incontrolable speeds when using low voxel
+     * sizes. */
+    /* When the voxel size is slower, it needs more precision. */
+    d = d * min_ff(pow2f(cd->init_voxel_size), 0.1f) * 0.05f;
+  }
+  if (cd->slow_mode) {
+    cd->voxel_size = cd->slow_voxel_size + d * 0.05f;
+  }
+  else {
+    cd->voxel_size = cd->init_voxel_size + d;
+  }
+
+  if (event->type == EVT_LEFTSHIFTKEY && event->val == KM_PRESS) {
+    cd->slow_mode = true;
+    copy_v2_v2(cd->slow_mval, mval);
+    cd->slow_voxel_size = cd->voxel_size;
+  }
+  if (event->type == EVT_LEFTSHIFTKEY && event->val == KM_RELEASE) {
+    cd->slow_mode = false;
+    cd->slow_voxel_size = 0.0f;
+  }
+
+  cd->voxel_size = clamp_f(cd->voxel_size, 0.0001f, 1.0f);
+
+  ED_region_tag_redraw(ar);
+  return OPERATOR_RUNNING_MODAL;
+}
+
+static int voxel_size_edit_invoke(bContext *C, wmOperator *op, const wmEvent *event)
+{
+  ARegion *ar = CTX_wm_region(C);
+  Object *active_object = CTX_data_active_object(C);
+  Mesh *mesh = (Mesh *)active_object->data;
+
+  VoxelSizeEditCustomData *cd = MEM_callocN(sizeof(VoxelSizeEditCustomData),
+                                            "Voxel Size Edit OP Custom Data");
+
+  /* Initial operator Custom Data setup. */
+  cd->draw_handle = ED_region_draw_cb_activate(
+      ar->type, voxel_size_edit_draw, cd, REGION_DRAW_POST_VIEW);
+  cd->active_object = active_object;
+  cd->init_mval[0] = event->mval[0];
+  cd->init_mval[1] = event->mval[1];
+  cd->init_voxel_size = mesh->remesh_voxel_size;
+  cd->voxel_size = mesh->remesh_voxel_size;
+  op->customdata = cd;
+
+  /* Select the front facing face of the mesh boundig box. */
+  BoundBox *bb = BKE_mesh_boundbox_get(cd->active_object);
+
+  /* Indices of the Bounding Box faces. */
+  int BB_faces[6][4] = {
+      {3, 0, 4, 7},
+      {1, 2, 6, 5},
+      {3, 2, 1, 0},
+      {4, 5, 6, 7},
+      {0, 1, 5, 4},
+      {2, 3, 7, 6},
+  };
+
+  copy_v3_v3(cd->preview_plane[0], bb->vec[BB_faces[0][0]]);
+  copy_v3_v3(cd->preview_plane[1], bb->vec[BB_faces[0][1]]);
+  copy_v3_v3(cd->preview_plane[2], bb->vec[BB_faces[0][2]]);
+  copy_v3_v3(cd->preview_plane[3], bb->vec[BB_faces[0][3]]);
+
+  RegionView3D *rv3d = CTX_wm_region_view3d(C);
+
+  float mat[3][3];
+  float current_normal[3];
+  float view_normal[3] = {0.0f, 0.0f, 1.0f};
+
+  /* Calculate the view normal. */
+  invert_m4_m4(active_object->imat, active_object->obmat);
+  copy_m3_m4(mat, rv3d->viewinv);
+  mul_m3_v3(mat, view_normal);
+  copy_m3_m4(mat, active_object->imat);
+  mul_m3_v3(mat, view_normal);
+  normalize_v3(view_normal);
+
+  normal_tri_v3(current_normal, cd->preview_plane[0], cd->preview_plane[1], cd->preview_plane[2]);
+
+  float min_dot = dot_v3v3(current_normal, view_normal);
+  float current_dot = 1;
+
+  /* Check if there is a face that is more aligned towards the view. */
+  for (int i = 0; i < 6; i++) {
+    normal_tri_v3(
+        current_normal, bb->vec[BB_faces[i][0]], bb->vec[BB_faces[i][1]], bb->vec[BB_faces[i][2]]);
+    current_dot = dot_v3v3(current_normal, view_normal);
+
+    if (current_dot < min_dot) {
+      min_dot = current_dot;
+      copy_v3_v3(cd->preview_plane[0], bb->vec[BB_faces[i][0]]);
+      copy_v3_v3(cd->preview_plane[1], bb->vec[BB_faces[i][1]]);
+      copy_v3_v3(cd->preview_plane[2], bb->vec[BB_faces[i][2]]);
+      copy_v3_v3(cd->preview_plane[3], bb->vec[BB_faces[i][3]]);
+    }
+  }
+
+  /* Matrix calculation to position the text in 3D space. */
+  float text_pos[3];
+  float scale_mat[4][4];
+
+  float d_a[3], d_b[3];
+  float d_a_proj[2], d_b_proj[2];
+  float preview_plane_proj[4][3];
+  float y_axis_proj[2] = {0.0f, 1.0f};
+
+  mid_v3_v3v3(text_pos, cd->preview_plane[0], cd->preview_plane[2]);
+
+  /* Project the selected face in the previous step of the Bounding Box. */
+  for (int i = 0; i < 4; i++) {
+    ED_view3d_project(ar, cd->preview_plane[i], preview_plane_proj[i]);
+  }
+
+  /* Get the initial X and Y axis of the basis from the edges of the Bounding Box face. */
+  sub_v3_v3v3(d_a, cd->preview_plane[1], cd->preview_plane[0]);
+  sub_v3_v3v3(d_b, cd->preview_plane[3], cd->preview_plane[0]);
+  normalize_v3(d_a);
+  normalize_v3(d_b);
+
+  /* Project the X and Y axis. */
+  sub_v2_v2v2(d_a_proj, preview_plane_proj[1], preview_plane_proj[0]);
+  sub_v2_v2v2(d_b_proj, preview_plane_proj[3], preview_plane_proj[0]);
+  normalize_v2(d_a_proj);
+  normalize_v2(d_b_proj);
+
+  unit_m4(cd->text_mat);
+
+  /* Select the axis that is aligned with the view Y axis to use it as the basis Y. */
+  if (fabsf(dot_v2v2(d_a_proj, y_axis_proj)) > fabsf(dot_v2v2(d_b_proj, y_axis_proj))) {
+    copy_v3_v3(cd->text_mat[0], d_b);
+    copy_v3_v3(cd->text_mat[1], d_a);
+
+    /* Flip the X and Y basis vectors to make sure they always point upwards and to the right. */
+    if (d_b_proj[0] < 0.0f) {
+      mul_v3_fl(cd->text_mat[0], -1.0f);
+    }
+    if (d_a_proj[1] < 0.0f) {
+      mul_v3_fl(cd->text_mat[1], -1.0f);
+    }
+  }
+  else {
+    copy_v3_v3(cd->text_mat[0], d_a);
+    copy_v3_v3(cd->text_mat[1], d_b);
+    if (d_a_proj[0] < 0.0f) {
+      mul_v3_fl(cd->text_mat[0], -1.0f);
+    }
+    if (d_b_proj[1] < 0.0f) {
+      mul_v3_fl(cd->text_mat[1], -1.0f);
+    }
+  }
+
+  /* Use the Bounding Box face normal as the basis Z. */
+  normal_tri_v3(cd->text_mat[2], cd->preview_plane[0], cd->preview_plane[1], cd->preview_plane[2]);
+
+  /* Write the text position into the matrix. */
+  copy_v3_v3(cd->text_mat[3], text_pos);
+
+  /* Scale the text.  */
+  unit_m4(scale_mat);
+  scale_m4_fl(scale_mat, 0.0008f);
+  mul_m4_m4_post(cd->text_mat, scale_mat);
+
+  WM_event_add_modal_handler(C, op);
+
+  ED_region_tag_redraw(ar);
+
+  const char *status_str = TIP_(
+      "Move the mouse to change the voxel size. LBM: confirm size, ESC/RMB: cancel");
+  ED_workspace_status_text(C, status_str);
+
+  return OPERATOR_RUNNING_MODAL;
+}
+
+void OBJECT_OT_voxel_size_edit(wmOperatorType *ot)
+{
+  /* identifiers */
+  ot->name = "Edit Voxel Size";
+  ot->description = "Modify the mesh voxel size interactively used in the voxel remesher";
+  ot->idname = "OBJECT_OT_voxel_size_edit";
+
+  /* api callbacks */
+  ot->poll = object_remesh_poll;
+  ot->invoke = voxel_size_edit_invoke;
+  ot->modal = voxel_size_edit_modal;
+  ot->cancel = voxel_size_edit_cancel;
+
+  ot->flag = OPTYPE_REGISTER | OPTYPE_UNDO;
+}
+
+/****************** quadriflow remesh operator *********************/
+
+#define QUADRIFLOW_MIRROR_BISECT_TOLERANCE 0.005f
+
 enum {
   QUADRIFLOW_REMESH_RATIO = 1,
   QUADRIFLOW_REMESH_EDGE_LENGTH,
   QUADRIFLOW_REMESH_FACES,
 };
 
-/****************** quadriflow remesh operator *********************/
-
-#define QUADRIFLOW_MIRROR_BISECT_TOLERANCE 0.005f
-
 typedef enum eSymmetryAxes {
   SYMMETRY_AXES_X = (1 << 0),
   SYMMETRY_AXES_Y = (1 << 1),