README.md

Projector

Creating a projector that "casts" a texture at a complicated 3D shape.

This example uses X3D nodes. Nodes used:

• Node TProjectedTextureCoordinateNode defines texture coordinates to cast a texture on a 3D shape. The projector created this way allows to cast a texture along the direction of some (maybe "fake", i.e. used only to cast texture) light or viewpoint.

  More information about ProjectedTextureCoordinate is in the manual about shadow maps and projective texturing.

• Light TSpotLightNode defines projector location/direction and size (light's cutOffAngle determines cast texture size).

The file data/projective_texturing_simple.x3dv in this project shows how to use these nodes -- you can double-click it to open in view3dscene, you can edit it in any text editor.

The example Pascal code adds these nodes to a glTF file exported from Blender.

The Projector location, direction and other properties can change at runtime freely, e.g. projector could rotate.

Note that example makes some assumptions, like:

• You have 1 projected texture.
• The mesh is initially not textured.

To overcome these limitations, you'd have to complicate adding the texture and texture coordinates: previous nodes have to be converted to lists (TMultiTextureNode, TMultiTextureCoordinateNode) to accomodate old and new textures. If this is unclear, just ask on our forum or Discord.

Using Castle Game Engine.

Building

Compile by:

• CGE editor. Just use menu items "Compile" or "Compile And Run".

• Or use CGE command-line build tool. Run castle-engine compile in this directory.

• Or use Lazarus. Open in Lazarus projector_standalone.lpi file and compile / run from Lazarus. Make sure to first register CGE Lazarus packages.

• Or use Delphi. Open in Delphi projector_standalone.dproj file and compile / run from Delphi. See CGE and Delphi documentation for details.