CN107038741B - Method for three-dimensionally rendering two-dimensional shadow - Google Patents
Method for three-dimensionally rendering two-dimensional shadow Download PDFInfo
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Abstract
The invention provides a method for three-dimensionally rendering a two-dimensional light shadow, which discovers that the two-dimensional light shadow effect is realized in three dimensions by deeply researching two dimensions and three dimensions, a normal line and a material of a model are required to be controlled, the relationship between the normal line and the light shadow is summarized by deeply researching the relationship between the two-dimensional light shadow, so that the two-dimensional light shadow has a clear and smooth structure, and the light shadow has color diversity, thereby solving the problems that the real environment is simulated according to the physical principle in the three-dimensional light shadow, the shadow is excessively soft, the projection is disordered, and the structure is not clear.
Description
Technical Field
The invention relates to a method for three-dimensionally rendering two-dimensional light and shadow.
Background
Three-dimensional simulation of a real environment is carried out according to a physical principle, the shadow is excessively soft, and the light and shadow structure is complex.
Two-dimensional is a highly generalized three-dimensional light and shadow representation, with a compact light shade and a structural height to restore a two-dimensional light and shadow.
Disclosure of Invention
The invention aims to provide a method for three-dimensionally rendering a two-dimensional light shadow, which can solve the problems that a real environment is simulated according to a physical principle in the three-dimensional light shadow, the shadow is excessively soft, the projection is disordered, and the structure is unclear.
In order to solve the above problems, the present invention provides a method for three-dimensionally rendering a two-dimensional shadow, comprising:
1) the vertex normal of the object is consistent with the direction of spherical radiation by taking the center of the object as an origin;
2) performing addition, subtraction and multiplication superposition operations of normal vectors on the basis of the existing vertex normal;
3) extracting a surface normal vector of the copied object, then finding a vertex with the shortest gravity center distance point of the surface of the copied object from the vertexes of the copied object, and copying the surface normal vector of the copied object onto the vertex normal;
4) the longitudinal and transverse anisotropies are utilized, the zeroing property of 2-time derivation of a high-order function is used, the change of a normal vector in the longitudinal direction and the transverse direction is realized, and the device has smooth and continuous characteristics.
Further, in the above method, aligning a vertex normal of the object with a direction of spherical radiation with an object center as an origin includes: and generating a continuous smooth normal vector gradual change between the original vertex normal vector and the spherical normal vector by utilizing the directionality of the vector, wherein the change magnitude of the normal vector is determined by a weight value, namely a sphericization value.
Further, in the above method, a continuous smooth gradient of the normal vector is generated between the original vertex normal vector and the spherical normal vector by using the directionality of the vector, wherein the magnitude of the change of the normal vector is determined by the weight value, i.e. the sphericization value, and the method includes: and subtracting the object center coordinate from the vertex coordinate to form a vector value, normalizing the vector value, copying the normalized vector value to the vertex normal, calculating an offset value based on each weight value, and superposing the offset value on the original vertex normal to form a spherical vertex normal based on the weight values.
Further, in the above method, the operations of adding, subtracting, and multiplicatively adding the normal vector are performed based on the existing vertex normal, and the operations include: and (3) performing conversion calculation on the existing vertex normal by using a three-dimensional affine equation, obtaining an offset through a weight value, retaining the offset in a parameter form, and simultaneously completing addition, subtraction and multiplication calculation.
Further, in the above method, a three-dimensional affine equation is used to perform conversion calculation on an existing vertex normal, an offset is obtained through a weight value, and the offset is retained in a form of a parameter, and meanwhile, addition, subtraction and multiplication calculation is completed, including: and performing linear calculation on the original normal vector by using a three-dimensional affine addition matrix and a three-dimensional affine multiplication matrix, obtaining an offset through a weight value, retaining the offset in a parameter form, and simultaneously completing addition, subtraction and multiplication calculation.
Further, in the above method, extracting a surface normal vector of the copied object, then finding a vertex with a shortest distance to a center of gravity point of the surface of the copied object among vertices of the copied object, and copying the surface normal vector of the copied object onto the vertex normal, includes: copying the surface normal vector of the object and the gravity center point of the triangular surface, calculating the distance from each vertex of the copied object to the gravity center point, if a plurality of vertices exist, obtaining the optimal vertex by using the minimum 2 multiplication, and copying the surface normal vector of the copied object to the vertex normal.
Further, in the above method, the variation of the normal vector in the longitudinal and transverse directions is realized by using the zeroing property of the 2-degree derivation of the high-order function, using the anisotropy in the longitudinal and transverse directions, and the method has a smooth and continuous characteristic, and includes: and (4) on the vertical and horizontal vertexes, the normal offset is evenly divided according to the Bessel spline curve, and the vertical component and the horizontal component of the vertical direction and the horizontal direction are superposed to obtain a smooth value.
Further, in the above method, on the longitudinal and transverse vertexes, the normal offset is equally divided according to the bezier spline curve, and then the longitudinal and transverse longitudinal components and the transverse component are superimposed to obtain a smoothed value, including: respectively obtaining 2 groups of vector value lists in the longitudinal direction and the transverse direction, equally dividing a normal longitudinal component and a normal transverse component in the longitudinal direction and the transverse direction according to a Bessel spline curve, and then performing addition calculation on the longitudinal component and the normal transverse component of the same vertex normal to obtain a final smooth normal.
Compared with the prior art, the invention discovers that the two-dimensional and three-dimensional deep researches show that the two-dimensional light and shadow effect is realized in three dimensions, the normal line and the material of the model are required to be controlled, the relation between the normal line and the light and shadow is summarized by deep researches on the two-dimensional light and shadow, so that the two-dimensional light and shadow has clear and smooth structure and color diversity, and the problems that the real environment is simulated according to the physical principle in the three-dimensional light and shadow, the shadow is excessively soft, the projection is disordered and the structure is not clear are solved.
Drawings
FIG. 1 is a flow chart of a method for three-dimensional rendering of two-dimensional shadows in accordance with an embodiment of the invention;
FIG. 2 is a photocopy of a document taken in accordance with one embodiment of the present invention;
FIG. 3 is a texture map of four colors given to a model according to an embodiment of the present invention;
FIG. 4 is a model normal parameter graph of an embodiment of the invention;
FIG. 5 is a graph of model normal results for one embodiment of the invention;
FIGS. 6a, 6b and 6c are parameter diagrams of an embodiment of the present invention;
FIG. 7 is a graph of the results of one embodiment of the present invention;
FIGS. 8a, 8b and 8c are detail tuning parameter diagrams of an embodiment of the present invention;
FIG. 9 is a diagram illustrating the result of detail adjustment according to an embodiment of the present invention;
Detailed Description
In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in further detail below.
As shown in fig. 1, the present invention provides a method for three-dimensionally rendering a two-dimensional shadow, comprising:
step S1, using the center of the object as the origin to make the vertex normal of the object and the direction of the spherical radiation consistent; here, the present step is a process of normal sphericization;
step S2, adding, subtracting, multiplying and superposing normal vectors on the basis of the existing vertex normal; here, this step is a process of normal addition multiplication;
step S3, extracting the surface normal vector of the copied object, then finding the vertex with the shortest gravity center distance point of the surface of the copied object in the copied object vertex, and copying the surface normal vector of the copied object to the vertex normal; here, this step is a process of normal copy;
step S4, using the longitudinal and transverse anisotropies, using the zeroing property of the 2-order derivation of the high-order function, to realize the change of the normal vector in the longitudinal and transverse directions, having smooth and continuous characteristics. Here, this step is a normal smoothing process; in the invention, through the deep research on two-dimension and three-dimension, the normal line and material of the model must be controlled to realize the two-dimension light shadow effect in the three-dimension, and the relationship between the normal line and the light shadow is summarized by deep research on the two-dimension light shadow, so that the two-dimension light shadow has clear and smooth structure, and the light shadow has color diversity, thereby solving the problems that the real environment is simulated according to the physical principle in the three-dimension light shadow, the shadow is excessively soft, the projection is disordered, and the structure is not clear.
In an embodiment of the present invention, the step S1 of making the vertex normal of the object and the spherical radiation direction coincide with each other with the center of the object as the origin includes:
and generating a continuous smooth normal vector gradual change between the original vertex normal vector and the spherical normal vector by utilizing the directionality of the vector, wherein the change magnitude of the normal vector is determined by a weight value, namely a sphericization value.
In an embodiment of the present invention, a continuous smooth gradual normal vector change is generated between an original vertex normal vector and a spherical normal vector by using the directionality of the vector, wherein the magnitude of the change of the normal vector is determined by a weight value, i.e., a sphericization value, and the method includes:
and subtracting the object center coordinate from the vertex coordinate to form a vector value, normalizing the vector value, copying the normalized vector value to the vertex normal, calculating an offset value based on each weight value, and superposing the offset value on the original vertex normal to form a spherical vertex normal based on the weight values.
In an embodiment of the present invention, step S2, performing addition, subtraction, multiplication and superposition operations of normal vectors based on the existing vertex normal, includes:
and (3) performing conversion calculation on the existing vertex normal by using a three-dimensional affine equation, obtaining an offset through a weight value, retaining the offset in a parameter form, and simultaneously completing addition, subtraction and multiplication calculation. Here, the calculated offset value can cancel the influence of the offset value on the original normal vector at any time, so that controllability of correction of the original normal vector can be realized.
In an embodiment of the present invention, a three-dimensional affine equation is used to perform conversion calculation on an existing vertex normal, an offset is obtained through a weight value, and the offset is retained in a form of a parameter, and meanwhile, addition, subtraction, multiplication calculation is completed, including:
and performing linear calculation on the original normal vector by using a three-dimensional affine addition matrix and a three-dimensional affine multiplication matrix, obtaining an offset through a weight value, retaining the offset in a parameter form, and simultaneously completing addition, subtraction and multiplication calculation. Here, the offset value is calculated and its effect on the original normal vector can be undone at any time.
In an embodiment of the present invention, in step S3, extracting a surface normal vector of the copied object, finding a vertex with a shortest distance from a center of gravity of the surface of the copied object among vertices of the copied object, and copying the surface normal vector of the copied object onto the vertex normal, includes:
copying the surface normal vector of the object and the gravity center point of the triangular surface, calculating the distance from each vertex of the copied object to the gravity center point, if a plurality of vertices exist, obtaining the optimal vertex by using the minimum 2 multiplication, and copying the surface normal vector of the copied object to the vertex normal.
In an embodiment of the present invention, the change of the normal vector in the longitudinal direction and the transverse direction is realized by using the longitudinal direction and the transverse direction anisotropy and the zeroing property of the 2-order derivation of the high-order function, and the change has smooth and continuous characteristics, including:
and (4) on the vertical and horizontal vertexes, the normal offset is evenly divided according to the Bessel spline curve, and the vertical component and the horizontal component of the vertical direction and the horizontal direction are superposed to obtain a smooth value.
In an embodiment of the present invention, on the longitudinal and transverse vertexes, the normal offset is equally divided according to the bezier spline curve, and the longitudinal and transverse longitudinal components and the transverse component are superimposed to obtain a smoothed value, including:
respectively obtaining 2 groups of vector value lists in the longitudinal direction and the transverse direction, equally dividing a normal longitudinal component and a normal transverse component in the longitudinal direction and the transverse direction according to a Bessel spline curve, and then performing addition calculation on the longitudinal component and the normal transverse component of the same vertex normal to obtain a final smooth normal.
In detail, a specific application example of the present invention comprises the following steps:
the first taken file shadow is shown in FIG. 2;
as shown in fig. 3, the material of four layers of colors on the model is given;
adjusting nodularization, addition, subtraction, multiplication and division of the model normal line by using a normal line tool to achieve a smooth and structured light and shadow effect as much as possible, wherein the model normal line parameter is shown in figure 4, and the model normal line result is shown in figure 5;
the offset position of the material ball color block is roughly adjusted to achieve the structural state, the parameters are shown in fig. 6a, 6b and 6c, and the result is shown in fig. 7;
highlight is added and the position of the highlight is adjusted, the position of the local color block is adjusted, and finally the detail adjustment parameters are shown in fig. 8a, 8b and 8c, and the result is shown in fig. 9.
In summary, in order to reduce the number of materials which can be displayed in real time in the traditional materials, the invention develops a multitask two-dimensional material which can be displayed in real time and can be rendered by software.
The embodiments in the present description are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments are referred to each other.
Those of skill would further appreciate that the various illustrative elements and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware, computer software, or combinations of both, and that the various illustrative components and steps have been described above generally in terms of their functionality in order to clearly illustrate this interchangeability of hardware and software. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the implementation. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present invention.
It will be apparent to those skilled in the art that various changes and modifications may be made in the invention without departing from the spirit and scope of the invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include such modifications and variations.
Claims (6)
1. A method of three-dimensionally rendering a two-dimensional shadow, comprising:
1) the method for making the vertex normal of the object consistent with the direction of spherical radiation by taking the center of the object as an origin comprises the following steps: generating a continuous smooth gradual change of the normal vector between the normal vector of the original vertex and the normal vector of the sphere by utilizing the directionality of the vector, wherein the change size of the normal vector is determined by a weight value, namely a sphericization value;
2) performing addition, subtraction and multiplication superposition operations of normal vectors on the basis of the existing vertex normal;
3) extracting a surface normal vector of the copied object, then finding a vertex with the shortest gravity center distance point of the surface of the copied object from the vertexes of the copied object, and copying the surface normal vector of the copied object onto the vertex normal;
4) the change of the normal vector in the longitudinal direction and the transverse direction is realized by utilizing the anisotropy of the longitudinal direction and the transverse direction and the zeroing property of 2-time derivation of a high-order function, and the change has smooth and continuous characteristics and comprises the following steps: and (4) on the vertical and horizontal vertexes, the normal offset is evenly divided according to the Bessel spline curve, and the vertical component and the horizontal component of the vertical direction and the horizontal direction are superposed to obtain a smooth value.
2. The method of claim 1, wherein the generating a continuous smooth gradient of normal vector between the original vertex normal vector and the spherical normal vector by using the directionality of the vector, wherein the magnitude of the change of the normal vector is determined by a weighting value (sphericization value) comprising: and subtracting the object center coordinate from the vertex coordinate to form a vector value, normalizing the vector value, copying the normalized vector value to the vertex normal, calculating an offset value based on each weight value, and superposing the offset value on the original vertex normal to form a spherical vertex normal based on the weight values.
3. The method of three-dimensional rendering of two-dimensional shadows of claim 2, wherein the operations of adding, subtracting, and multiplicatively superimposing normal vectors on the basis of existing vertex normals include: and (3) performing conversion calculation on the existing vertex normal by using a three-dimensional affine equation, obtaining an offset through a weight value, retaining the offset in a parameter form, and simultaneously completing addition, subtraction and multiplication calculation.
4. The method of claim 3, wherein the converting calculation is performed on the existing vertex normal by using a three-dimensional affine equation, and then an offset is obtained by a weight value, and the offset is retained in a form of a parameter while performing the addition and subtraction multiplication calculation, and the method comprises: and performing linear calculation on the original normal vector by using a three-dimensional affine addition matrix and a three-dimensional affine multiplication matrix, obtaining an offset through a weight value, retaining the offset in a parameter form, and simultaneously completing addition, subtraction and multiplication calculation.
5. The method of three-dimensional rendering of two-dimensional shadows of claim 4, wherein extracting surface normal vectors of the replicated object, finding a vertex of the replicated object with the shortest distance between the center of gravity points of the surface of the replicated object among the vertices of the replicated object, and replicating the surface normal vector of the replicated object onto the vertex normal, comprises: copying the surface normal vector of the object and the gravity center point of the triangular surface, calculating the distance from each vertex of the copied object to the gravity center point, if a plurality of vertices exist, obtaining the optimal vertex by using the minimum 2 multiplication, and copying the surface normal vector of the copied object to the vertex normal.
6. The method of three-dimensional rendering of two-dimensional shadows according to claim 5, wherein the step of obtaining a smoothed value by equally dividing the normal offset by a bezier spline curve at the longitudinal and transverse vertices and by superimposing the longitudinal and transverse components comprises: respectively obtaining 2 groups of vector value lists in the longitudinal direction and the transverse direction, equally dividing a normal longitudinal component and a normal transverse component in the longitudinal direction and the transverse direction according to a Bessel spline curve, and then performing addition calculation on the longitudinal component and the normal transverse component of the same vertex normal to obtain a final smooth normal.
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