Image rendering
View Patent ↗A method of forming a two dimensional map of a three dimensional environment, there being a map origin located in the three dimensional environment, a viewing direction vector defined passing through the map origin, and a one-to-one correspondence between map positions in the map and the directions of vectors passing through the map origin; comprises the steps of: associating an environment position in the three dimensional environment with a folded vector that passes through the map origin, the folded vector lying in a plane containing both the viewing direction vector and the environment position and forming an angle with the viewing direction vector that is a predetermined function of the angle between the viewing direction vector and a vector between the map origin and the environment position; associating an environment position with the map position corresponding to the direction of the folded vector associated with that environment position; and deriving properties for a map position from the properties of the corresponding environment position.
1. A method performed by a computer of forming a two dimensional map of a three dimensional environment, there being a map origin located in the three dimensional environment, a viewing direction vector defined passing through the map origin, and a one-to-one correspondence between map positions in the map and the directions of vectors passing through the map origin;
the method comprising the steps of:
associating by the computer an environment position in the three dimensional environment with a folded vector that passes through the map origin, the folded vector lying in a plane containing both the viewing direction vector and the environment position and forming an angle with the viewing direction vector that is a predetermined function of the angle between the viewing direction vector and a vector between the map origin and the environment position;
associating by the computer an environment position with the map position corresponding to the direction of the folded vector associated with that environment position; and
deriving by the computer properties for a map position from the properties of the corresponding environment position;
wherein the predetermined function is a multiplication by 0.5.
2. A method according to claim 1 , in which the one-to-one correspondence of a map point with the direction of a vector through the map origin represents a projection onto a predetermined plane of a point on the vector which is a predetermined distance from the map origin.
3. A method according to claim 2 , in which the predetermined plane is a plane orthogonal to the viewing direction vector.
4. An image rendering method comprising the steps of:
generating a two dimensional map of a three dimensional environment using a method according to claim 1 ;
for a point of interest on an object to be displayed, deriving a reflection vector in dependence on a normal vector at the point of interest and a direction of view;
referencing a position in the two dimensional map using the reflection vector, to detect environmental properties at that map position; and
varying the appearance of the object at the point of interest in dependence on the detected environmental properties.
5. A method according to claim 4 , in which the varying step is performed in dependence on a reflectivity of the object at the point of interest.
6. A method according to claim 4 , in which the environmental properties represent lighting properties.
7. A non-transitory computer-readable medium having instructions stored therein which when executed, cause a computer to perform the method according to claim 1 .
8. Apparatus for forming a two dimensional map of a three dimensional environment, there being a map origin located in the three dimensional environment, a viewing direction vector defined passing through the map origin, and a one-to-one correspondence between map positions in the map and the directions of vectors passing through the map origin; the apparatus comprising:
means for associating an environment position in the three dimensional environment with a folded vector that passes through the map origin, the folded vector lying in a plane containing both the viewing direction vector and the environment position and forming an angle with the viewing direction vector that is a predetermined function of the angle between the viewing direction vector and a vector between the map origin and the environment position;
means for associating an environment position with the map position corresponding to the direction of the folded vector associated with that environment position; and
means for deriving properties for a map position from the properties of the corresponding environment position;
wherein the predetermined function is a multiplication by 0.5.
9. An image rendering apparatus comprising:
map generating apparatus according to claim 8 ;
means for deriving a reflection vector, in respect of a point of interest on an object to be displayed, in dependence on a normal vector at the point of interest and a direction of view;
means for referencing a position in the two dimensional map using the reflection vector, to detect environmental properties at that map position; and
means for varying the appearance of the object at the point of interest in dependence on the detected environmental properties.
10. A video game machine comprising apparatus according to claim 8 .