CN106780704B - The direct lighting effect proximity rendering method of three-dimensional scenic reused based on visibility - Google Patents

Abstract

The present invention relates to a kind of direct lighting effect proximity rendering methods of three-dimensional scenic reused based on visibility, it is characterised in that: virtual camera is placed on viewpoint position, according to normal observation parameter, utilizes light projective technique drawing three-dimensional scene；For the light A001 of every pixel from viewpoint in virtual pixel plane, pixel on light A001 and virtual pixel plane corresponds, judge whether light A001 intersects with the geometric object of three-dimensional scenic, the intersection point A002, intersection point A002 nearest from viewpoint that the geometric object of light A001 and three-dimensional scenic is further calculated if intersection is a visible scene point B001；Its by reuse area source sampled point visibility processing as a result, come accelerate area source irradiation three-dimensional scenic direct lighting effect drafting speed and improve rendering quality.

Description

The direct lighting effect proximity rendering method of three-dimensional scenic reused based on visibility

Technical field

The present invention relates to a kind of direct lighting effect proximity rendering methods of three-dimensional scenic reused based on visibility, belong to three Tie up scene drawing technical field.

Background technique

Area source is one of real world common light sources type.Three-dimensional scenic under area source irradiation would generally be presented Soft shadows feature.Traditionally, the direct light of the three-dimensional scenic of area source irradiation is realized using monte carlo integration technology It is drawn according to effect.Using the direct lighting effect of the three-dimensional scenic of monte carlo integration technology to drawing area source irradiation, need The sampled point of certain amount is generated on area source, and is calculated the visibility between light source sampled point and visible scene point and (completed yin Shadow calculates), and then light source sampled point is calculated to the direct illumination contributions of visible scene point.It can visually be connect to draw out The direct lighting effect picture of the three-dimensional scenic received generally requires to generate a large amount of sampled points on area source, calculates light source sampled point Visibility between visible scene point can become important performance bottleneck.It is worth noting that, area source different from point light source Often there is very strong correlation to the visibility of adjacent visual scene point.This characteristic is made full use of, the present invention passes through opposite The visibility processing result of light source sampled point is reused, to reduce the direct illumination effect for the three-dimensional scenic for drawing area source irradiation The cost of fruit, and improve rendering quality.

Summary of the invention

The purpose of the present invention is to provide a kind of direct lighting effect proximity renderings of three-dimensional scenic reused based on visibility Method, by reusing the visibility processing of area source sampled point as a result, to accelerate the direct of the three-dimensional scenic of area source irradiation The drafting speed of lighting effect simultaneously improves rendering quality.

The technical scheme of the present invention is realized as follows: approximate based on the direct lighting effect of three-dimensional scenic that visibility reuses Method for drafting, it is characterised in that: virtual camera is placed on viewpoint position, according to normal observation parameter, projects skill using light Art drawing three-dimensional scene；For the light A001, light A001 of every pixel from viewpoint in virtual pixel plane It is corresponded with the pixel in virtual pixel plane, judges whether light A001 intersects with the geometric object of three-dimensional scenic, if Intersecting the intersection point A002, intersection point A002 nearest from viewpoint of geometric object for then further calculating light A001 and three-dimensional scenic is One visible scene point B001, while being randomly generated on area sourceNUMIt is a to obey equally distributed light source sampled point B003, note Record thisNUMThe spatial position of a light source sampled point B003, and calculate between each light source sampled point B003 and intersection point A002 can Opinion property VIS；For each intersection point A002, by the area source sampling and the visibility that reuse the adjacent visual scene point of intersection point A002 Calculated result accelerates to calculate the approximation directly illumination contributions value of area source antinode A002；The specific implementation steps are as follows:

A kind of data structure LSPD is provided, for storing data relevant to area source sampled point；Data structure LSPD packet Include the spatial position of light source sampled point and two member variables of visibility of light source sampled point.

1) it realizes the sampling to area source, and calculates the visibility between area source sampled point and visible scene point, tool Steps are as follows for body:

Virtual camera: being placed on viewpoint position by step Step101, according to normal observation parameter, projects skill using light Art drawing three-dimensional scene；For the light A001, light A001 of every pixel from viewpoint in virtual pixel plane It is corresponded with the pixel in virtual pixel plane, judges whether light A001 intersects with the geometric object of three-dimensional scenic, if Intersecting the intersection point A002, intersection point A002 nearest from viewpoint of geometric object for then further calculating light A001 and three-dimensional scenic is One visible scene point B001, visible scene point B001 have corresponded to a unique pixel in virtual pixel plane；

Step Step102: creating one includesMRow,NThe array LS of column element,MFor the pixel column in virtual pixel plane Number,NFor the pixel columns in virtual pixel plane；Each element of array LS stores a list B002, and list B002's is every A element stores the variable of a data structure LSPD type；The list B002 for enabling each element of array LS store is sky；Number Pixel on each element and virtual pixel plane of group LS corresponds.

Step Step103: it for each visible scene point B001, performs the following operations:

It is randomly generated on area sourceNUMIt is a to obey equally distributed light source sampled point B003；In computer storage CreationNUMThe variable of a data structure LSPD type, withNUMA light source sampled point B003 is corresponded；Each light source is adopted The spatial position of sampling point B003 is assigned to the space bit of the light source sampled point of the variable of corresponding data structure LSPD type Set member variable；For each light source sampled point B003, judge from the spatial position of light source sampled point B003 to visible scene point Whether the line segment of B001 intersects with the geometric object of three-dimensional scenic, if intersection, enables number corresponding with light source sampled point B003 Value according to the visibility member variable of the light source sampled point of the variable of structure LSPD type is 0, is otherwise enabled and light source sampled point The value of the visibility member variable of the light source sampled point of the variable of the corresponding data structure LSPD type of B003 is 1；NUMA light Source sampling point B003 is correspondingNUMThe variable of a data structure LSPD type is added to the corresponding virtual representation of visible scene point B001 In the list B002 of the element storage of the corresponding array LS of pixel in plain plane.

2) approximation of each visible scene point directly illumination value is calculated, and draws out the direct illumination effect of three-dimensional scenic Fruit, the specific steps are as follows:

Step Step201: creating one includesMRow,NThe array ILU of column element,MFor the pixel in virtual pixel plane Line number,NFor the pixel columns in virtual pixel plane；Pixel on each element of array ILU and virtual pixel plane is one by one Corresponding, each element of array ILU is used to save the direct illumination of the corresponding visible scene point of pixel in virtual pixel plane Value；The value for enabling each element of array ILU is the corresponding illumination value of background colour；

Step Step202: it for each visible scene point B001 obtained in step Step101, performs the following operations:

Step Step202-1: enabling variable SUM=0, variable NS=0, SUM is accumulated variables, and NS is counting variable；Meter Calculate line number irow and row number jcol of the corresponding pixel of visible scene point B001 where go virtual pixel plane；Enable LIST1 table The list B002 of the element storage of the i-th row row, jth col column of registration group LS；For each element B 004 in LIST1, enable NS=NS+1, if the visibility member of the light source sampled point of the variable for the data structure LSPD type that element B 004 stores The value of variable is equal to 1, then the space bit of the light source sampled point of the variable of the data structure LSPD type stored according to element B 004 Set the light source sampling point position that member variable stored, position, the position visible scene point B001 of visible scene point B001 Geometric object surface normal, geometric object where visible scene point B001 material quality data, calculating elements B004 storage The light source sampling point position pair that the spatial position member variable of the light source sampled point of the variable of data structure LSPD type is stored The light source sampled point answered is to the direct illumination contributions value B005 of visible scene point B001, the value and direct illumination tribute of variable SUM It offers the sum of value B005 and is assigned to variable SUM；

Step Step202-2: for the adjacent picture of each of the pixel arranged of the i-th row row, the jth col in virtual pixel plane Plain B006, performs the following operations:

Line number Irow and row number Jcol of the pixel B 006 where go virtual pixel plane are calculated, LIST2 is enabled to indicate array The list B002 of the element storage of the I row row, Jcol column of LS；For each element B 007 in LIST2, NS=NS is enabled + 1, if the value of the visibility member variable of the light source sampled point of the variable for the data structure LSPD type that element B 007 stores Equal to 1, then the spatial position member of the light source sampled point of the variable of the data structure LSPD type stored according to element B 007 becomes Measure the geometry pair of stored light source sampling point position, the position of visible scene point B001, the position visible scene point B001 The material quality data of geometric object as where surface normal, visible scene point B001, the data structure of calculating elements B007 storage The corresponding light source of light source sampling point position that the spatial position member variable of the light source sampled point of the variable of LSPD type is stored Direct illumination contributions value B008 of the sampled point to visible scene point B001, value and direct illumination contributions value B008 variable SUM The sum of be assigned to variable SUM；

Step Step202-3: the i-th row row of array ILU, jth the col element arranged be assigned a value of the value of variable SUM divided by The product of the value of variable NS resulting result and area source area；

Step Step203: the direct illumination value that each element of array ILU saves is converted into three-dimensional scenic picture image Pixel color value, and three-dimensional scenic picture image is shown over the display.

Good effect of the present invention is that there are stronger correlations for area source is utilized to adjacent visual scene point visibility The characteristics of.When calculating direct illumination contributions of the area source to some visible scene point, visible scene point adjacent thereto is reused Area source sampling and its visibility processing as a result, being estimated to increase for the direct illumination contributions of visible scene point with lesser cost The area source sampling number of meter, so as to achieve the purpose that improve rendering quality.

Detailed description of the invention

Fig. 1 is adjacent visible scene point and its corresponding light source sampled point schematic diagram.

Specific embodiment

In order to which the features and advantages of the present invention are more clearly understood, the present invention is made into one combined with specific embodiments below The description of step.

Embodiment 1

The CPU of computer system selects Intel (R) Xeon (R) CPU E3-1225 v3@3.20GHz, memory choosing Jin Shidun 8GB DDR3 1333 is selected, disk selects 1.5 TU2 of Buffalo HD-CE, and video card selects NVidia Quadro K2000；Computer operating system selects Windows 7, software programming tools selection VC++ 2010.

As shown in Figure 1, visible scene point A (101) and visible scene point B (102) are two adjacent visible scene points, light Source sampling point A (105) and light source sampled point B (106) is two on area source (104) corresponding with visible scene point B (102) A sampled point, light source sampled point C (107) and light source sampled point D (108) are area sources corresponding with visible scene point A (101) (104) two sampled points on, geometric object (103) are a geometric objects in three-dimensional scenic.Although being only in Fig. 1 Each visible scene point depicts two corresponding light source sampled points, and the corresponding light source sampling number of each visible scene point can be with Greater than 2.

Virtual camera is placed on viewpoint position, according to normal observation parameter, utilizes light projective technique drawing three-dimensional field Scape；Light A001, light A001 and virtual pixel for every pixel from viewpoint in virtual pixel plane is flat Pixel on face corresponds, and judges whether light A001 intersects with the geometric object of three-dimensional scenic, further if intersection The intersection point A002, intersection point A002 nearest from viewpoint for calculating the geometric object of light A001 and three-dimensional scenic is a visible scene Point B001, while being randomly generated on area sourceNUMIt is a to obey equally distributed light source sampled point B003, record thisNUMA light The spatial position of source sampling point B003, and calculate the visibility VIS between each light source sampled point B003 and intersection point A002；For Each intersection point A002 is added by reusing area source sampling and the visibility processing result of the adjacent visual scene point of intersection point A002 Speed calculates the approximation directly illumination contributions value of area source antinode A002；The specific implementation steps are as follows for technical solution:

A kind of data structure LSPD is provided, for storing data relevant to area source sampled point；Data structure LSPD packet Include the spatial position of light source sampled point and two member variables of visibility of light source sampled point.

First part realizes the sampling to area source, and calculates visible between area source sampled point and visible scene point Property, the specific steps are as follows:

Virtual camera: being placed on viewpoint position by step Step101, according to normal observation parameter, projects skill using light Art drawing three-dimensional scene；For the light A001, light A001 of every pixel from viewpoint in virtual pixel plane It is corresponded with the pixel in virtual pixel plane, judges whether light A001 intersects with the geometric object of three-dimensional scenic, if Intersecting the intersection point A002, intersection point A002 nearest from viewpoint of geometric object for then further calculating light A001 and three-dimensional scenic is One visible scene point B001, visible scene point B001 have corresponded to a unique pixel in virtual pixel plane；

Step Step102: creating one includesMRow,NThe array LS of column element,MFor the pixel column in virtual pixel plane Number,NFor the pixel columns in virtual pixel plane；Each element of array LS stores a list B002, and list B002's is every A element stores the variable of a data structure LSPD type；The list B002 for enabling each element of array LS store is sky；Number Pixel on each element and virtual pixel plane of group LS corresponds.

Step Step103: it for each visible scene point B001, performs the following operations:

It is randomly generated on area sourceNUMIt is a to obey equally distributed light source sampled point B003；In computer storage CreationNUMThe variable of a data structure LSPD type, withNUMA light source sampled point B003 is corresponded；Each light source is adopted The spatial position of sampling point B003 is assigned to the space bit of the light source sampled point of the variable of corresponding data structure LSPD type Set member variable；For each light source sampled point B003, judge from the spatial position of light source sampled point B003 to visible scene point Whether the line segment of B001 intersects with the geometric object of three-dimensional scenic, if intersection, enables number corresponding with light source sampled point B003 Value according to the visibility member variable of the light source sampled point of the variable of structure LSPD type is 0, is otherwise enabled and light source sampled point The value of the visibility member variable of the light source sampled point of the variable of the corresponding data structure LSPD type of B003 is 1；NUMA light Source sampling point B003 is correspondingNUMThe variable of a data structure LSPD type is added to the corresponding virtual representation of visible scene point B001 In the list B002 of the element storage of the corresponding array LS of pixel in plain plane.

Second part, which is realized, calculates the approximation directly illumination value of each visible scene point, and draws out the straight of three-dimensional scenic Connect lighting effect, the specific steps are as follows:

Step Step201: creating one includesMRow,NThe array ILU of column element,MFor the pixel in virtual pixel plane Line number,NFor the pixel columns in virtual pixel plane；Pixel on each element of array ILU and virtual pixel plane is one by one Corresponding, each element of array ILU is used to save the direct illumination of the corresponding visible scene point of pixel in virtual pixel plane Value；The value for enabling each element of array ILU is the corresponding illumination value of background colour；

Step Step202: it for each visible scene point B001 obtained in step Step101, performs the following operations:

Step Step202-1: variable SUM=0, variable NS=0 are enabled；The corresponding pixel of visible scene point B001 is calculated to exist Line number irow and row number jcol where go virtual pixel plane；LIST1 is enabled to indicate that the i-th row row of array LS, jth col arrange The list B002 of element storage；For each element B 004 in LIST1, NS=NS+1 is enabled, if what element B 004 stored The value of the visibility member variable of the light source sampled point of the variable of data structure LSPD type is equal to 1, then is deposited according to element B 004 The light source sample that the spatial position member variable of the light source sampled point of the variable of the data structure LSPD type of storage is stored It sets, the position of visible scene point B001, the geometric object surface normal of the position visible scene point B001, visible scene point The material quality data of geometric object where B001, the light source sampling of the variable of the data structure LSPD type of calculating elements B004 storage The corresponding light source sampled point of light source sampling point position that the spatial position member variable of point is stored is to visible scene point B001's The sum of the value of variable SUM and direct illumination contributions value B005, are assigned to variable SUM by direct illumination contributions value B005；

Step Step202-2: for the adjacent picture of each of the pixel arranged of the i-th row row, the jth col in virtual pixel plane Plain B006, performs the following operations:

Line number Irow and row number Jcol of the pixel B 006 where go virtual pixel plane are calculated, LIST2 is enabled to indicate array The list B002 of the element storage of the I row row, Jcol column of LS；For each element B 007 in LIST2, NS=NS is enabled + 1, if the value of the visibility member variable of the light source sampled point of the variable for the data structure LSPD type that element B 007 stores Equal to 1, then the spatial position member of the light source sampled point of the variable of the data structure LSPD type stored according to element B 007 becomes Measure the geometry pair of stored light source sampling point position, the position of visible scene point B001, the position visible scene point B001 The material quality data of geometric object as where surface normal, visible scene point B001, the data structure of calculating elements B007 storage The corresponding light source of light source sampling point position that the spatial position member variable of the light source sampled point of the variable of LSPD type is stored Direct illumination contributions value B008 of the sampled point to visible scene point B001, value and direct illumination contributions value B008 variable SUM The sum of be assigned to variable SUM；

Step Step202-3: the i-th row row of array ILU, jth the col element arranged be assigned a value of the value of variable SUM divided by The product of the value of variable NS resulting result and area source area；

Step Step203: the direct illumination value that each element of array ILU saves is converted into three-dimensional scenic picture image Pixel color value, and three-dimensional scenic picture image is shown over the display.

In the present embodiment,NUMValue is 5,MValue is 768,NValue is 1024.

Claims (1)

1. the direct lighting effect proximity rendering method of three-dimensional scenic reused based on visibility, it is characterised in that: virtual camera It is placed on viewpoint position, according to normal observation parameter, utilizes light projective technique drawing three-dimensional scene；Every is gone out from viewpoint The light A001 of the pixel in virtual pixel plane is sent out, the pixel on light A001 and virtual pixel plane corresponds, Judge whether light A001 intersects with the geometric object of three-dimensional scenic, further calculates light A001 and three dimensional field if intersection The intersection point A002, intersection point A002 nearest from viewpoint of the geometric object of scape is a visible scene point B001, while in area source On be randomly generated NUM and obey equally distributed light source sampled point B003, record the space bit of this NUM light source sampled point B003 It sets, and calculates the visibility VIS between each light source sampled point B003 and intersection point A002；For each intersection point A002, pass through weight Accelerated to calculate area source antinode with the sampling of the area source of the adjacent visual scene point of intersection point A002 and visibility processing result The approximation of A002 directly illumination contributions value；The specific implementation steps are as follows:

A kind of data structure LSPD is provided, for storing data relevant to area source sampled point；Data structure LSPD includes light The spatial position of source sampling point and two member variables of visibility of light source sampled point；

1) it realizes the sampling to area source, and calculates the visibility between area source sampled point and visible scene point, it is specific to walk It is rapid as follows:

Virtual camera: being placed on viewpoint position by step Step101, according to normal observation parameter, is drawn using light projective technique Three-dimensional scenic processed；Light A001, light A001 and void for every pixel from viewpoint in virtual pixel plane Pixel on quasi- pixel planes corresponds, and judges whether light A001 intersects with the geometric object of three-dimensional scenic, if intersection The intersection point A002, intersection point A002 nearest from viewpoint for then further calculating the geometric object of light A001 and three-dimensional scenic is one Visible scene point B001, visible scene point B001 have corresponded to a unique pixel in virtual pixel plane；

Step Step102: creation one array LS, M comprising M row, N column element are the number of lines of pixels in virtual pixel plane, N For the pixel columns in virtual pixel plane；Each element of array LS stores a list B002, each member of list B002 The variable of element one data structure LSPD type of storage；The list B002 for enabling each element of array LS store is sky；Array LS Each element and virtual pixel plane on pixel correspond；

Step Step103: it for each visible scene point B001, performs the following operations:

NUM is randomly generated on area source and obeys equally distributed light source sampled point B003；It creates in computer storage The variable of NUM data structure LSPD type is corresponded with NUM light source sampled point B003；Each light source sampled point The spatial position of B003 be assigned to the spatial position of the light source sampled point of the variable of corresponding data structure LSPD type at Member's variable；For each light source sampled point B003, judge from the spatial position of light source sampled point B003 to visible scene point B001 Line segment whether intersect with the geometric object of three-dimensional scenic, if intersection, enable corresponding with light source sampled point B003 data knot The value of the visibility member variable of the light source sampled point of the variable of structure LSPD type is 0, is otherwise enabled and B003 pairs of light source sampled point The value of the visibility member variable of the light source sampled point of the variable for the data structure LSPD type answered is 1；NUM light source is sampled The variable of the corresponding NUM data structure LSPD type of point B003 is added to the corresponding virtual pixel plane of visible scene point B001 On the corresponding array LS of pixel element storage list B002 in；

2) approximation of each visible scene point directly illumination value is calculated, and draws out the direct lighting effect of three-dimensional scenic, had Steps are as follows for body:

Step Step201: creation one array ILU, M comprising M row, N column element are the number of lines of pixels in virtual pixel plane, N is the pixel columns in virtual pixel plane；Each element of array ILU and the pixel in virtual pixel plane correspond, Each element of array ILU is used to save the direct illumination value of the corresponding visible scene point of pixel in virtual pixel plane；It enables The value of each element of array ILU is equal to the corresponding illumination value of background colour；

Step Step202: it for each visible scene point B001 obtained in step Step101, performs the following operations:

Step Step202-1: enabling variable SUM=0, variable NS=0, SUM is accumulated variables, and NS is counting variable；It calculates visual Line number irow and row number jcol of the corresponding pixel of scene point B001 where go virtual pixel plane；LIST1 is enabled to indicate array The list B002 of the element storage of the i-th row row, jth col column of LS；For each element B 004 in LIST1, NS=NS+ is enabled 1, if the value etc. of the visibility member variable of the light source sampled point of the variable for the data structure LSPD type that element B 004 stores In 1, then the spatial position member variable of the light source sampled point of the variable of the data structure LSPD type stored according to element B 004 The geometric object of the position of the light source sampling point position, visible scene point B001 that are stored, the position visible scene point B001 The material quality data of geometric object where surface normal, visible scene point B001, the data structure of calculating elements B004 storage The corresponding light source of light source sampling point position that the spatial position member variable of the light source sampled point of the variable of LSPD type is stored Direct illumination contributions value B005 of the sampled point to visible scene point B001, value and direct illumination contributions value B005 variable SUM The sum of be assigned to variable SUM；

Step Step202-2: for each adjacent pixel of the pixel of the i-th row row, jth col column in virtual pixel plane B006 is performed the following operations:

Line number Irow and row number Jcol of the pixel B 006 where go virtual pixel plane are calculated, LIST2 is enabled to indicate array LS's The list B002 of the element storage of I row row, Jcol column；For each element B 007 in LIST2, NS=NS+1 is enabled, such as The value of the visibility member variable of the light source sampled point of the variable for the data structure LSPD type that fruit element B 007 stores is equal to 1, The spatial position member variable of the light source sampled point of the variable of the data structure LSPD type then stored according to element B 007 is deposited The light source sampling point position of storage, the position of visible scene point B001, the position visible scene point B001 geometric object surface The material quality data of geometric object where normal vector, visible scene point B001, the data structure LSPD class of calculating elements B007 storage The corresponding light source sampled point of the light source sampling point position that the spatial position member variable of the light source sampled point of the variable of type is stored To the direct illumination contributions value B008 of visible scene point B001, the sum of the value of variable SUM and direct illumination contributions value B008 are assigned It is worth and gives variable SUM；

Step Step202-3: the i-th row row, the jth col of array the ILU element arranged are assigned a value of the value of variable SUM divided by variable The product of the value of NS resulting result and area source area；

Step Step203: the direct illumination value that each element of array ILU saves is converted into three-dimensional scenic picture image pixel Color value, and three-dimensional scenic picture image is shown over the display.