System and method for real time dynamic lighting simulation
Sustainable building lighting and energy modelling and control, and the associated computer graphics, including real-time dynamic lighting simulation, are concerned with: an optimized method for radiance modelling, including its application to predictive daylight harvesting; and the real-time simulation of physically-based electric lighting and daylighting for architectural, horticultural, and theatrical lighting systems visualization. In order to display and analyze in real time a photometrically accurate representation of an environment, thousands of lighting channels may have their intensity settings continually varied such that a user may interactively view the three-dimensional environment without the need for ongoing global illumination calculations. This can be accomplished utilizing texture maps as a multiplicity of canonical radiosity solutions, each representing a lighting channel for dynamic lighting simulation, and storing the solutions in the texture memory of a graphics processing unit.
1. A system for displaying real-time dynamic lighting simulations, comprising:
one or more processors;
a display device;
one or more graphics processing units (GPUs); and
one or more memory devices storing computer-readable instructions, which, when executed by the one or more processors cause the system to:
encode a texture map as a multiplicity of canonical radiosity solutions, each representing a lighting channel;
store the canonical radiosity solutions in a texture memory of the one or more GPUs;
generate a multiplicity of lighting channel intensity settings;
store the lighting channel intensity settings in the one or more memory devices;
access the canonical radiosity solutions on a per-vertex basis with a vertex shader program;
multiply vertex channel colors associated with the vertices by the lighting channel intensity settings;
sum resultant colors to generate a display vertex color; and
display the vertex color on the display device.
2. The system of claim 1 wherein the computer-readable instructions, when executed by the one or more processors, cause the system to:
use, for each vertex, a vertex constant color value from the texture map to initialize the display vertex color with one of the multiplicity of canonical radiosity solutions;
wherein said one canonical radiosity solution represents a direct and indirect illuminance distribution within an environment for constant electric light sources.
3. The system of claim 2 wherein the computer-readable instructions, when executed by the one or more processors, cause the system to:
initialize a vertex channel color texel array index in order to access a spectral radiant exitances array associated with each vertex.
4. The system of claim 3 , wherein the computer-readable instructions, when executed by the one or more processors, cause the system to process one or more active color channels by:
fetching a vertex channel color texel from the texture map;
multiplying the vertex channel color represented by the texel with an associated global channel dimmer setting or sky patch luminance;
adding the vertex channel color to the display vertex color;
incrementing the vertex channel color texel array index; and
processing the next active color channel, if any.
5. The system of claim 2 , comprising, in the one or more GPUs, a multiplicity of GPU processor cores, wherein the computer-readable instructions, when executed by the one or more processors, cause the system to apply an inverse gamma correction to the display vertex color, by:
correcting each component of a red-green-blue triplet with an inverse gamma correction;
setting vertex texture coordinates as required for the vertex shader program;
calculating a vertex position as required for the vertex shader program; and
executing a fragment shader program on a per-pixel basis for an entire displayed image, utilizing the multiplicity of GPU processor cores.
6. The system of claim 1 , wherein the computer-readable instructions, when executed by the one or more processors, cause the system to:
enable textures for a displayed image; and
initialize a fragment color as an input color times a texel color.
7. The system of claim 6 , wherein:
the vertex belongs to an opaque surface; and
the computer-readable instructions, when executed by the one or more processors, cause the system to:
specify an exposure setting to lighten or darken the displayed image; and
multiply the fragment color by the exposure setting.
8. The system of claim 7 , wherein the computer-readable instructions, when executed by the one or more processors, cause the system to:
output a value of the fragment color as required for a fragment shader program.
9. The system of claim 7 , wherein the computer-readable instructions, when executed by the one or more processors, cause the system to:
specify a grayscale display:
calculate the fragment color as a luminance of its red-green-blue values;
calculate the fragment color as a pseudocolor; and
output a value of the fragment color as required for a fragment shader program.
10. The system of claim 1 , wherein the computer-readable instructions, when executed by the one or more processors, cause the system to initialize a fragment color as an input color.
11. The system of claim 10 , wherein:
the vertex belongs to an opaque surface; and
the computer-readable instructions, when executed by the one or more processors, cause the system to:
specify an exposure setting to lighten or darken the displayed image; and
multiply the fragment color by the exposure setting.
12. The system of claim 11 , wherein the computer-readable instructions, when executed by the one or more processors, cause the system to:
specify a grayscale display:
calculate the fragment color as a luminance of its red-green-blue values;
calculate the fragment color as a pseudocolor; and
output a value of the fragment color as required for a fragment shader program.
13. The system of claim 1 , comprising a daylight harvesting modelling system, wherein the computer-readable instructions, when executed by the one or more processors, cause the system to display, on the display device, a real-time dynamic lighting simulation for a building, a space in the building, a horticultural lighting purpose, a greenhouse or a theatre.
14. Computer readable memory storing computer-readable instructions, which, when executed by one or more processors cause a lighting modelling system to:
encode a texture map as a multiplicity of canonical radiosity solutions, each representing a lighting channel;
store the canonical radiosity solutions in a texture memory of one or more graphics processing units (GPUs);
generate a multiplicity of lighting channel intensity settings;
store the lighting channel intensity settings;
access the canonical radiosity solutions on a per-vertex basis with a vertex shader program;
multiply vertex channel colors associated with the vertices by the lighting channel intensity settings;
sum resultant colors to generate a display vertex color; and
display the vertex color.
15. The computer readable memory of claim 14 wherein the computer-readable instructions, when executed by the one or more processors, cause the lighting modelling system to:
use, for each vertex, a vertex constant color value from the texture map to initialize the display vertex color with one of the multiplicity of canonical radiosity solutions;
wherein said one canonical radiosity solution represents a direct and indirect illuminance distribution within an environment for constant electric light sources.
16. The computer readable memory of claim 15 wherein the computer-readable instructions, when executed by the one or more processors, cause the lighting modelling system to:
initialize a vertex channel color texel array index in order to access a spectral radiant exitances array associated with each vertex.
17. The computer readable memory of claim 16 , wherein the computer-readable instructions, when executed by the one or more processors, cause the lighting modelling system to process one or more active color channels by:
fetching a vertex channel color texel from the texture map;
multiplying the vertex channel color represented by the texel with an associated global channel dimmer setting or sky patch luminance;
adding the vertex channel color to the display vertex color;
incrementing the vertex channel color texel array index; and
processing the next active color channel, if any.
18. The computer readable memory of claim 15 , wherein the computer-readable instructions, when executed by the one or more processors, cause the lighting modelling system to apply an inverse gamma correction to the display vertex color, by:
correcting each component of a red-green-blue triplet with an inverse gamma correction;
setting vertex texture coordinates as required for the vertex shader program;
calculating a vertex position as required for the vertex shader program; and
executing a fragment shader program on a per-pixel basis for an entire displayed image, utilizing a multiplicity of processor cores in the one or more GPUs.
19. The computer readable memory of claim 14 , wherein the computer-readable instructions, when executed by the one or more processors, cause the lighting modelling system to:
enable textures for a displayed image; and
initialize a fragment color as an input color times a texel color.
20. The computer readable memory of claim 19 , wherein:
the vertex belongs to an opaque surface; and
the computer-readable instructions, when executed by the one or more processors, cause the lighting modelling system to:
specify an exposure setting to lighten or darken the displayed image; and
multiply the fragment color by the exposure setting.
21. The computer readable memory of claim 20 , wherein the computer-readable instructions, when executed by the one or more processors, cause the lighting modelling system to:
output a value of the fragment color as required for a fragment shader program.
22. The computer readable memory of claim 20 , wherein the computer-readable instructions, when executed by the one or more processors, cause the lighting modelling system to:
specify a grayscale display:
calculate the fragment color as a luminance of its red-green-blue values;
calculate the fragment color as a pseudocolor; and
output a value of the fragment color as required for a fragment shader program.
23. The computer readable memory of claim 14 , wherein the computer-readable instructions, when executed by the one or more processors, cause the lighting modelling system to initialize a fragment color as an input color.
24. The computer readable memory of claim 23 , wherein:
the vertex belongs to an opaque surface; and
the computer-readable instructions, when executed by the one or more processors, cause the lighting modelling system to:
specify an exposure setting to lighten or darken the displayed image; and
multiply the fragment color by the exposure setting.
25. The computer readable memory of claim 24 , wherein the computer-readable instructions, when executed by the one or more processors, cause the lighting modelling system to:
specify a grayscale display:
calculate the fragment color as a luminance of its red-green-blue values;
calculate the fragment color as a pseudocolor; and
output a value of the fragment color as required for a fragment shader program.
26. The computer readable memory of claim 14 , wherein the computer-readable instructions, when executed by the one or more processors, cause the lighting modelling system to display, on the display device, a real-time dynamic lighting simulation for a building, a space in the building, a horticultural lighting purpose, a greenhouse or a theatre.