Implement automatic LOD (Level of Detail)

-Happens on import by default for all models
-Just works (tm)
-Biasing can be later adjusted per node or per viewport (as well as globally)
-Disabled AABB.get_support test because its broken

3 files changed, 16 insertions, 3 deletions

diff --git a/core/math/aabb.h b/core/math/aabb.h
index 45dcbc7f7f..474304eae2 100644
--- a/core/math/aabb.h
+++ b/core/math/aabb.h
@@ -190,9 +190,9 @@ Vector3 AABB::get_support(const Vector3 &p_normal) const {
 	Vector3 ofs = position + half_extents;
 
 	return Vector3(
-				   (p_normal.x > 0) ? -half_extents.x : half_extents.x,
-				   (p_normal.y > 0) ? -half_extents.y : half_extents.y,
-				   (p_normal.z > 0) ? -half_extents.z : half_extents.z) +
+				   (p_normal.x > 0) ? half_extents.x : -half_extents.x,
+				   (p_normal.y > 0) ? half_extents.y : -half_extents.y,
+				   (p_normal.z > 0) ? half_extents.z : -half_extents.z) +
 		   ofs;
 }
 
diff --git a/core/math/camera_matrix.cpp b/core/math/camera_matrix.cpp
index 5e5efb6356..f29cb7a269 100644
--- a/core/math/camera_matrix.cpp
+++ b/core/math/camera_matrix.cpp
@@ -655,6 +655,17 @@ real_t CameraMatrix::get_fov() const {
 	}
 }
 
+float CameraMatrix::get_lod_multiplier() const {
+	if (is_orthogonal()) {
+		return get_viewport_half_extents().x;
+	} else {
+		float zn = get_z_near();
+		float width = get_viewport_half_extents().x * 2.0;
+		return 1.0 / (zn / width);
+	}
+
+	//usage is lod_size / (lod_distance * multiplier) < threshold
+}
 void CameraMatrix::make_scale(const Vector3 &p_scale) {
 	set_identity();
 	matrix[0][0] = p_scale.x;
diff --git a/core/math/camera_matrix.h b/core/math/camera_matrix.h
index c5cdd98377..f856a7b1bf 100644
--- a/core/math/camera_matrix.h
+++ b/core/math/camera_matrix.h
@@ -108,6 +108,8 @@ struct CameraMatrix {
 		return !(*this == p_cam);
 	}
 
+	float get_lod_multiplier() const;
+
 	CameraMatrix();
 	CameraMatrix(const Transform &p_transform);
 	~CameraMatrix();