add simplified camera offset formula

3 files changed, 19 insertions, 6 deletions

diff --git a/editor/camera.cpp b/editor/camera.cpp
index 3fa8d9d3..72b90cc2 100644
--- a/editor/camera.cpp
+++ b/editor/camera.cpp
@@ -89,7 +89,7 @@ object_id app::get_object_colliding_with_cursor()
                     continue;
                 auto& c = *cʹ;
                 c.ensure_passability();
-                const with_shifted_camera_offset o{shader, c_pos, {minx, miny}, {maxx, maxy}};
+                const with_shifted_camera_offset o{shader, c_pos};
                 if (floormat_main::check_chunk_visible(shader.camera_offset(), sz))
                 {
                     constexpr auto chunk_size = TILE_SIZE2 * TILE_MAX_DIM;
@@ -144,8 +144,7 @@ Vector2 app::point_screen_pos(point pt)
     auto& shader = M->shader();
     auto win_size = M->window_size();
     auto c3 = pt.chunk3();
-    auto c2 = pt.chunk();
-    with_shifted_camera_offset co{shader, c3, c2, c2 };
+    with_shifted_camera_offset co{shader, c3};
     auto world_pos = TILE_SIZE20 * Vector3(pt.local()) + Vector3(Vector2(pt.offset()), 0);
     return Vector2(shader.camera_offset()) + Vector2(win_size)*.5f + shader.project(world_pos);
 }
diff --git a/src/camera-offset.cpp b/src/camera-offset.cpp
index 46582539..27899b03 100644
--- a/src/camera-offset.cpp
+++ b/src/camera-offset.cpp
@@ -4,6 +4,18 @@
 
 namespace floormat {
 
+Vector2d with_shifted_camera_offset::get_offset(chunk_coords_ c)
+{
+    return tile_shader::project(Vector3d(Vector2d(c.x, c.y) * TILE_MAX_DIM, c.z) * dTILE_SIZE);
+}
+
+with_shifted_camera_offset::with_shifted_camera_offset(tile_shader& shader, chunk_coords_ c) :
+    _shader{shader}, _camera{shader.camera_offset()}
+{
+    auto offset = _camera + get_offset(c);
+    _shader.set_camera_offset(offset, float{1 << 24});
+}
+
 with_shifted_camera_offset::with_shifted_camera_offset(tile_shader& shader, chunk_coords_ c_, chunk_coords first_, chunk_coords last_) :
     _shader{shader},
     _camera{shader.camera_offset()}
@@ -11,8 +23,7 @@ with_shifted_camera_offset::with_shifted_camera_offset(tile_shader& shader, chun
     (void)last_;
     fm_assert(shader.depth_offset() == 0.f);
 
-    auto z = int{c_.z};
-    auto offset = _camera + tile_shader::project((Vector3d(c_.x, c_.y, 0) * TILE_MAX_DIM20d + Vector3d(0, 0, z)) * dTILE_SIZE);
+    auto offset = _camera + get_offset(c_);
     auto pos  = chunk_coords(c_) - first_;
     constexpr auto depth_start = -1 + 1.111e-16f;
 
@@ -22,7 +33,7 @@ with_shifted_camera_offset::with_shifted_camera_offset(tile_shader& shader, chun
     printf("c=(%2hd %2hd %2hhd) pos=(%2d %2d) len=(%d %d) --> %d\n", c_.x, c_.y, c_.z, pos.x(), pos.y(), len.x(), len.y(), depth);
 #endif
 
-    auto z_offset = (z-chunk_z_min) * tile_shader::depth_value({}, tile_shader::z_depth_offset);
+    auto z_offset = (int{c_.z}-int{chunk_z_min}) * tile_shader::depth_value({}, tile_shader::z_depth_offset);
     auto d = depth * tile_shader::depth_tile_size + depth_start + z_offset;
 
     if (c_.z == chunk_z_max)
diff --git a/src/camera-offset.hpp b/src/camera-offset.hpp
index f3b64177..88a1a08a 100644
--- a/src/camera-offset.hpp
+++ b/src/camera-offset.hpp
@@ -9,8 +9,11 @@ struct tile_shader;
 
 struct with_shifted_camera_offset final
 {
+    explicit with_shifted_camera_offset(tile_shader& shader, chunk_coords_ c);
     explicit with_shifted_camera_offset(tile_shader& shader, chunk_coords_ c, chunk_coords first, chunk_coords last);
     ~with_shifted_camera_offset();
+
+    static Vector2d get_offset(chunk_coords_ c);
 private:
     tile_shader& _shader; // NOLINT
     Vector2d _camera;