Method MoveBox

src/game/collision.cpp:521–594

}

void CCollision::MoveBox(vec2 *pInoutPos, vec2 *pInoutVel, vec2 Size, vec2 Elasticity, bool *pGrounded) const
{
	// do the move
	vec2 Pos = *pInoutPos;
	vec2 Vel = *pInoutVel;

	float Distance = length(Vel);
	int Max = (int)Distance;

	if(Distance > 0.00001f)
	{
		float Fraction = 1.0f / (float)(Max + 1);
		float ElasticityX = std::clamp(Elasticity.x, -1.0f, 1.0f);
		float ElasticityY = std::clamp(Elasticity.y, -1.0f, 1.0f);

		for(int i = 0; i <= Max; i++)
		{
			// Early break as optimization to stop checking for collisions for
			// large distances after the obstacles we have already hit reduced
			// our speed to exactly 0.
			if(Vel == vec2(0, 0))
			{
				break;
			}

			vec2 NewPos = Pos + Vel * Fraction; // TODO: this row is not nice

			// Fraction can be very small and thus the calculation has no effect, no
			// reason to continue calculating.
			if(NewPos == Pos)
			{
				break;
			}

			if(TestBox(vec2(NewPos.x, NewPos.y), Size))
			{
				int Hits = 0;

				if(TestBox(vec2(Pos.x, NewPos.y), Size))
				{
					if(pGrounded && ElasticityY > 0 && Vel.y > 0)
						*pGrounded = true;
					NewPos.y = Pos.y;
					Vel.y *= -ElasticityY;
					Hits++;
				}

				if(TestBox(vec2(NewPos.x, Pos.y), Size))
				{
					NewPos.x = Pos.x;
					Vel.x *= -ElasticityX;
					Hits++;
				}

				// neither of the tests got a collision.
				// this is a real _corner case_!
				if(Hits == 0)
				{