The Design And Implementation Of A Fast Construction Algorithms Of The Signed Distance Field Based On Ray Casting

A Signed Distance Field(SDF)is a scalar field that represents the closest distance from any point in space to the surface of a given geometry.It uses distance values to represent spatial position information and symbols to represent directions.In this way,the relative position relationship between the current point and a given target geometry can be indicated clearly.With the rapid development of computer graphics processor hardware,people are more pursuing to draw high-realism,high-quality picture effects.The scene is becoming larger and more complex,which constantly puts forward new challenges to these existing rendering technology such as SDF.Therefore,it is important to propose a kind of directed distance field construction algorithm which can be applied to large scenes or complex scenes and achieve a balance between time and accuracy.The fast construction algorithm of SDF based on ray Casting is studied in three aspects:dynamic distance calculation for optimizing ray casting,adaptive distance sampling algorithm,and dynamic error control for ray casting model.Firstly,the dynamic distance calculation of ray casting is optimized,so that each ray dynamically changes the emission length according to the current directed distance field value,thereby reducing the time cost of ray casting.Secondly,this paper gives a dynamic error control method for ray casting models,and provides a method to dynamically adjust the amount of light emission under specified error conditions.Finally,this paper presents a sampling algorithm based on the index adaptive distance that can more accurately calculate the distance value from the point to the triangle surface when the light rays intersect the triangular surface.The above three points are combined to design and implement the algorithm,which is verified in the Crytek Sponza experimental scenario and compared with the existing methods from multiple angles.Final experimental results show that the fast construction algorithm of SDF based on ray casting can effectively improve the operation efficiency under the condition of ensuring the correct rate of calculation,and can construct a SDF steadily and quickly to meet the rendering needs of complex scenes and large scenes,which has certain application significance in the related fields of SDF.