Move tool apply to selection

Still a work in progress.  Need to cleanup the view so that we don't
show all those boxes.

Also undo is not working very well because it doesn't take into account
the selection.

src/tools.c

@@ -22,11 +22,12 @@ static const tool_t *g_tools[TOOL_COUNT] = {};
 
 static void a_tool_set(void *data)
 {
+    tool_t *tool = data;
     if (goxel.tool_volume) {
         volume_delete(goxel.tool_volume);
         goxel.tool_volume = NULL;
     }
-    goxel.tool = (tool_t*)data;
+    goxel.tool = tool;
 }
 
 void tool_register_(tool_t *tool)

src/tools/move.c

@@ -25,6 +25,12 @@ enum {
 
 typedef struct {
     tool_t tool;
+
+    uint64_t start_mask_key;
+    volume_t *start_volume;
+    volume_t *start_selection;
+    float box[4][4];
+    float start_box[4][4];
 } tool_move_t;
 
 static bool layer_is_volume(const layer_t *layer)
@@ -73,6 +79,14 @@ static void move(layer_t *layer, const float mat[4][4])
     }
 }
 
+// Compute transformation betwen two matrices.
+static void get_transf(const float src[4][4], const float dst[4][4],
+                       float out[4][4])
+{
+    mat4_invert(src, out);
+    mat4_mul(dst, out, out);
+}
+
 static void normalize_box(const float box[4][4], float out[4][4])
 {
     mat4_copy(box, out);
@@ -81,9 +95,57 @@ static void normalize_box(const float box[4][4], float out[4][4])
     bbox_from_npoints(out, 8, vertices);
 }
 
-static int iter(tool_t *tool, const painter_t *painter,
+static int iter_selection(tool_move_t *tool, const painter_t *painter,
+                          const float viewport[4])
+{
+    float transf[4][4];
+    float transf_tot[4][4];
+    int box_edit_state;
+    layer_t *layer = goxel.image->active_layer;
+    volume_t *tmp;
+
+    if (tool->start_mask_key != volume_get_key(goxel.mask)) {
+        volume_get_box(goxel.mask, true, tool->box);
+        tool->start_mask_key = volume_get_key(goxel.mask);
+    }
+
+    box_edit_state = box_edit(tool->box, DRAG_MOVE, transf);
+    if (!box_edit_state) return 0;
+
+    if (box_edit_state == GESTURE3D_STATE_BEGIN) {
+        assert(!tool->start_volume && !tool->start_selection);
+        mat4_copy(tool->box, tool->start_box);
+        tool->start_volume = volume_copy(layer->volume);
+        volume_merge(tool->start_volume, goxel.mask, MODE_SUB, NULL);
+        tool->start_selection = volume_copy(layer->volume);
+        volume_merge(tool->start_selection, goxel.mask, MODE_INTERSECT, NULL);
+    }
+
+    mat4_mul(transf, tool->box, tool->box);
+    get_transf(tool->start_box, tool->box, transf_tot);
+    tmp = volume_copy(tool->start_selection);
+    volume_move(tmp, transf_tot);
+    volume_set(layer->volume, tool->start_volume);
+    volume_merge(layer->volume, tmp, MODE_OVER, NULL);
+    volume_delete(tmp);
+
+    if (box_edit_state == GESTURE3D_STATE_END) {
+        volume_delete(tool->start_volume);
+        volume_delete(tool->start_selection);
+        tool->start_volume = NULL;
+        tool->start_selection = NULL;
+        tool->box[3][3] = 0;
+        volume_move(goxel.mask, transf_tot);
+        image_history_push(goxel.image);
+    }
+
+    return 0;
+}
+
+static int iter(tool_t *tool_, const painter_t *painter,
                 const float viewport[4])
 {
+    tool_move_t *tool = (void*)tool_;
     float transf[4][4];
     float origin_box[4][4] = MAT4_IDENTITY;
     uint8_t color[4] = {255, 0, 0, 255};
@@ -93,6 +155,10 @@ static int iter(tool_t *tool, const painter_t *painter,
 
     layer_t *layer = goxel.image->active_layer;
 
+    if (goxel.mask && !volume_is_empty(goxel.mask)) {
+        return iter_selection(tool, painter, viewport);
+    }
+
     if (layer->shape) drag_mode = DRAG_RESIZE;
 
     volume_get_box(goxel.image->active_layer->volume, true, box);