GVRDeepShadowMapping¶

MacroModule¶

author	`MeVis Medical Solutions AG`
package	`MeVisLab/Standard`
definition	GVRDeepShadowMapping.def

Purpose¶

The GVRDeepShadowMapping implements deep shadow mapping. The implementation is based on the paper “GPU-accelerated deep shadow maps for direct volume rendering” by Markus Hadwiger et. al. (see http://portal.acm.org/citation.cfm?id=1283908). Many thanks go to Markus Hadwiger for providing the GLSL shaders that are used in the module.

The module has high hardware requirements (it requires floating point textures and FBO rendering to 3D textures) and will be quite slow if not used on up-to-date graphics cards. It has not yet been tested on ATI cards.

Clipping planes are supported, but the shadow volume does not take them into account, the shader turns off shadowing near the clip planes. Mask volumes, Tag volumes and other secondary volumes are supported for the shadow creation. The classification step of the shadow creation can be manually modified using the SoGVRShaderFunction in the scene below this module.

Usage¶

The module needs to be placed in front of a SoGVRVolumeRenderer module. The LUT and the SoGVRRayCastSettings need to be placed in front of this module, otherwise the shadow map generation will fail. The SoGVRVolumeRenderer needs to be connected to the input of this module as well, this is used for the shadow generation pass.

Details¶

A screenshot of a segmented brain, rendered with shadow mapping:

../../../Modules/Macros/GVR/mhelp/Images/DeepShadowMapping.png

Windows¶

Default Panel¶

../../../Modules/Macros/GVR/mhelp/Images/Screenshots/GVRDeepShadowMapping._default.png

Input Fields¶

nodeIn0¶

name: nodeIn0, type: SoNode¶

Output Fields¶

nodeOut0¶

name: nodeOut0, type: SoNode¶

Parameter Fields¶

Field Index¶

`Altitude`: `Float`	`Shadow Map Layers`: `Integer`
`Attach Light To Camera`: `Bool`	`Shadow Map Size`: `Integer`
`Azimuth`: `Float`
`Compression Epsilon`: `Float`
`Interactive Mode`: `Enum`
`Interactive Shadow Map Layers`: `Integer`
`Interactive Shadow Map Size`: `Integer`
`Shadow Fetch Mode`: `Enum`

Visible Fields¶

Attach Light To Camera¶

name: attachLightToCamera, type: Bool, default: TRUE¶: If enabled, the light is positioned in camera/view space, if disabled it is positioned in world-space.

Azimuth¶

name: lightPolarPhi, type: Float, default: 45, minimum: -180, maximum: 180¶: Polar coordinate Phi of the light.

Altitude¶

name: lightPolarRho, type: Float, default: -45, minimum: -180, maximum: 180¶: Polar coordinate Rho of the light.

Compression Epsilon¶

name: compressionEpsilon, type: Float, default: 0.0099999998, minimum: 0, maximum: 0.5¶: Alpha compression epsilon used for DSM creation.

Shadow Map Layers¶

name: shadowMapLayers, type: Integer, default: 16¶: The number of layers the DSM texture uses.

Shadow Map Size¶

name: shadowMapSize, type: Integer, default: 1024¶: The size used for width and height of the shadow map.

Interactive Shadow Map Layers¶

name: interactiveShadowMapLayers, type: Integer, default: 4¶: Depth of interactive shadow map.

Interactive Shadow Map Size¶

name: interactiveShadowMapSize, type: Integer, default: 512¶: Size of interactive shadow map.

Interactive Mode¶

name: interactiveMode, type: Enum, default: GVR_USE_STATIC_SHADOW¶: Defines what to do while rendering interactively.

Values:

Title	Name	Description
Lowres Shadow	GVR_USE_LOWRES_SHADOW	Use the `Interactive Shadow Map Layers` and `Interactive Shadow Map Size` fields for shadow creation.
Hires Shadow	GVR_USE_HIRES_SHADOW	Use the `Shadow Map Layers` and `Shadow Map Size` fields for shadow creation.
Static Shadow	GVR_USE_STATIC_SHADOW	Use the shadow that was created on the last static rendering step (so the light will rotate with the volume).

Shadow Fetch Mode¶

name: shadowFetchMode, type: Enum, default: Nearest¶: Defines how the attenuation values of the shadow are fetched.