add simplified camera offset formula

1 files changed, 14 insertions, 3 deletions

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)