Collision detection - Smooth wall sliding, no bounce effect

Question

I'm working on a basic collision detection system that provides point - OBB collision detection. I have around 200 cubes in my environment and I check (for now) each of them in turn and see if it collides. If it does I return the colliding face's normal, save the old player position and do some trigonometry to return a new player position for my wall sliding.

edit
I'll define my meaning of wall sliding: If a player walks in a vertical slope and has a slight horizontal rotation to the left or the right and keeps walking forward in the wall the player should slide a little to the right/left while continually walking towards the wall till he left the wall. Thus, sliding along the wall.

Everything works fine and with multiple objects as well but I still have one problem I can't seem to figure out: smooth wall sliding. In my current implementation sliding along the walls make my player bounce like a mad man (especially noticable with gravity on and moving forward).

I have a velocity/direction vector, a normal vector from the collided plane and an old and new player position. First I negate the normal vector and get my new velocity vector by substracting the inverted normal from my direction vector (which is the vector to slide along the wall) and I add this vector to my new Player position and recalculate the direction vector (in case I have multiple collisions).

I know I am missing some step but I can't seem to figure it out.

Here is my code for the collision detection (run every frame):

Vector direction;
Vector newPos(camera.GetOriginX(), camera.GetOriginY(), camera.GetOriginZ());
direction = newPos - oldPos; // Direction vector
// Check for collision with new position
for(int i = 0; i < NUM_OBJECTS; i++)
{
    Vector normal = objects[i].CheckCollision(newPos.x, newPos.y, newPos.z, direction.x, direction.y, direction.z);
    if(normal != Vector::NullVector())
    {
        // Get inverse normal (direction STRAIGHT INTO wall)
        Vector invNormal = normal.Negative();
        Vector wallDir = direction - invNormal; // We know INTO wall, and DIRECTION to wall. Substract these and you got slide WALL direction
        newPos = oldPos + wallDir;
        direction = newPos - oldPos;
    }
}

Any help would be greatly appreciated!

---

FIX I eventually got things up and running how they should thanks to Krazy, I'll post the updated code listing in case someone else comes upon this problem!

for(int i = 0; i < NUM_OBJECTS; i++)
{
    Vector normal = objects[i].CheckCollision(newPos.x, newPos.y, newPos.z, direction.x, direction.y, direction.z);
    if(normal != Vector::NullVector())
    {
        Vector invNormal = normal.Negative();
        invNormal = invNormal * (direction * normal).Length(); // Change normal to direction's length and normal's axis
        Vector wallDir = direction - invNormal;
        newPos = oldPos + wallDir;
        direction = newPos - oldPos;
    }
}

Answer 1

I think you need to multiply invNormal by the length of direction before making the subtraction.

Vector invNormal = normal.Negative();
invNormal *= direction.length
Vector wallDir = direction - invNormal;

Answer 2

You want to lose all the velocity in the direction of the normal of the wall. To do this, project the current direction onto the wall normal to get the wall part of the velocity/direction.

projected = normal * dot(direction, normal);
direction = direction - projected

Last line might have to have the sign flipped depending on the normals direction (in or out of the wall).