From b256fc903af678a7af8162c9878ab44d287e80df Mon Sep 17 00:00:00 2001
From: veclavtalica <veclavtalica@tutamail.com>
Date: Tue, 11 Mar 2025 02:41:03 +0300
Subject: [PATCH] /apps/tools/twndel: triangluation, triangle render

---
 apps/tools/twndel/state.h |  3 +-
 apps/tools/twndel/tool.c  | 81 +++++++++++++++++++++++++++++++--------
 2 files changed, 67 insertions(+), 17 deletions(-)

diff --git a/apps/tools/twndel/state.h b/apps/tools/twndel/state.h
index ff89ded..abcb362 100644
--- a/apps/tools/twndel/state.h
+++ b/apps/tools/twndel/state.h
@@ -45,9 +45,10 @@ typedef struct Point {
     int16_t x, y, z;
 } Point;
 
+/* TODO: store topology in terms on edge connections? might be bad, as it's stateful */
 /* triangles have p3 = INVALID_POINT */
 /* lines have p2, p3 = INVALID_POINT */
-/* points have p1, p2, p3 = INVALID_POINT */
+/* billboards have p1, p2, p3 = INVALID_POINT */
 typedef struct Face {
     uint16_t p[4];
     /* texture origin, as point on face plane, in absolute coordinates */
diff --git a/apps/tools/twndel/tool.c b/apps/tools/twndel/tool.c
index 0fac5eb..00d3a80 100644
--- a/apps/tools/twndel/tool.c
+++ b/apps/tools/twndel/tool.c
@@ -125,21 +125,33 @@ static void render_object(uint8_t object) {
                 draw_line_3d(p2, p3, 1, (Color){255,255,255,255});
                 draw_line_3d(p3, p0, 1, (Color){255,255,255,255});
             }
-        } else {
+
+        } else if (f->p[2] != INVALID_POINT) {
             Vec3 p0 = point_to_vec3(object, f->p[0]);
             Vec3 p1 = point_to_vec3(object, f->p[1]);
             Vec3 p2 = point_to_vec3(object, f->p[2]);
 
-            // if (state.solid_display_mode)
-            //     draw_triangle(state.current_texture,
-            //                  p0, p1, p2, )
-            // else {
-            //     draw_line_3d(p0, p1, 1, (Color){255,255,255,255});
-            //     draw_line_3d(p1, p2, 1, (Color){255,255,255,255});
-            //     draw_line_3d(p2, p3, 1, (Color){255,255,255,255});
-            //     draw_line_3d(p3, p0, 1, (Color){255,255,255,255});
-            // }
-        }
+            Vec3 n = vec3_norm(vec3_cross(vec3_sub(p1, p0), vec3_sub(p2, p0)));
+            Vec2 to = { f->tex_x / (float)POINTS_PER_METER, f->tex_y / (float)POINTS_PER_METER, };
+            Vec2 tul = project_texture_coordinate(to, n, p0, (float)f->tex_scale);
+            Vec2 tdl = project_texture_coordinate(to, n, p1, (float)f->tex_scale);
+            Vec2 tdr = project_texture_coordinate(to, n, p2, (float)f->tex_scale);
+
+            if (state.solid_display_mode)
+                draw_triangle(state.current_texture,
+                              p0, p1, p2,
+                              tul, tdl, tdr,
+                              (Color){255,255,255,255},
+                              (Color){255,255,255,255},
+                              (Color){255,255,255,255});
+            else {
+                draw_line_3d(p0, p1, 1, (Color){255,255,255,255});
+                draw_line_3d(p1, p2, 1, (Color){255,255,255,255});
+                draw_line_3d(p2, p0, 1, (Color){255,255,255,255});
+            }
+
+        } else
+            SDL_assert_always(false);
     }
 }
 
@@ -358,12 +370,12 @@ static void show_snap_lines(Vec3 p) {
 }
 
 
-static void process_operation_move_point(Operation *op) {
+static bool process_operation_move_point(Operation *op) {
     /* finish dragging around */
     /* TODO: dont keep empty ops on stack? */
     if (input_action_just_released("select")) {
         state.op_active = false;
-        return;
+        return false;
     }
 
     float size = sinf(ctx.frame_number / 10) * 0.05f + 0.05f;
@@ -418,8 +430,12 @@ static void process_operation_move_point(Operation *op) {
         }
     }
 
-    if (point_moved)
+    if (point_moved) {
         audio_play("/data/bong.ogg", NULL, false, 0.12f, 0.0f);
+        return true;
+    }
+
+    return false;
 }
 
 
@@ -432,6 +448,36 @@ static void reverse_operation_move_point(Operation *op) {
 }
 
 
+static void try_subdividing_from_moving(uint8_t object, uint16_t point) {
+    Object *o = &state.objects[object];
+
+    for (uint16_t fi = 0; fi < o->faces_sz; ++fi) {
+        Face *f = &o->faces[fi];
+        if (f->p[3] == INVALID_POINT) continue;
+        for (uint16_t pi = 0; pi < 4; ++pi) {
+            if (f->p[pi] == point) {
+                Face new0 = *f;
+                new0.p[0] = f->p[pi];
+                new0.p[1] = f->p[(pi + 1) % 4];
+                new0.p[2] = f->p[(pi + 3) % 4];
+                new0.p[3] = INVALID_POINT;
+
+                push_face(object,
+                          f->p[(pi + 1) % 4],
+                          f->p[(pi + 2) % 4],
+                          f->p[(pi + 3) % 4],
+                          INVALID_POINT,
+                          f->texture,
+                          f->tex_scale,
+                          f->tex_x,
+                          f->tex_y);
+                *f = new0;
+            }
+        }
+    }
+}
+
+
 static void process_operations(void) {
     if (input_action_just_pressed("undo")) {
         /* TODO: checks and defined limit */
@@ -463,7 +509,7 @@ static void process_operations(void) {
             if (input_action_just_pressed("select"))
                 push_operation((Operation){
                     .kind = OPERATION_MOVE_POINT,
-                    .data = { .move_point = { .point = point_select } },
+                    .data = { .move_point = { .point = point_select, .object = obj_select } },
                 }, true );
         }
     }
@@ -472,7 +518,10 @@ static void process_operations(void) {
         Operation *op = &state.op_stack[state.op_stack_ptr % UNDO_STACK_SIZE];
         switch (op->kind) {
         case OPERATION_MOVE_POINT: {
-            process_operation_move_point(op);
+            bool update = process_operation_move_point(op);
+
+            if (update)
+                try_subdividing_from_moving(op->data.move_point.object, op->data.move_point.point);
 
             break;
         }