Image Map Shader

Image Map Shader

Node Description and Purpose:
The Image Map Shader allows you to load an external image map file in one of many supported formats. You can find a complete list of the image formats supported here. You can control the way the texture is applied in the scene - the "projection" - the position, as well as whether to flip or repeat the loaded image, adjust the colour values, determine whether displacement is applied, and control other image-specific effects.

Node Type: Shader (colour and/or displacement)

Settings:

• Image filename: This is where you specify the image file used by the shader. You can use the button at right to open a Choose File dialog.

Projection, location Tab

• Projection type: This popup controls how the image is projected, or applied, to the scene. The popup has the following options:
  • Plan Y (edges = XZ): The image will be projected vertically through the scene, along the Y axis.
  • Side X (edges = YZ): The image will projected horizontally through the scene, along the X axis.
  • Size Z (edges = XY): The image will be projected horizontally through the scene, along the Z axis.
  • Through camera: The image will be projected using the camera specified in the Projection camera parameter.
  • Object UV (if available): The image will be mapped to object UV coordinates, if they're available.
  • Cylindrical: (TBC)
  • Spherical: (TBC)
• Projection camera: This setting lets you assign the camera used for projecting the image when the Projection type is set to Through Camera. You can use the Assign shader button (green plus) at right to select an existing camera or create a new one. You can create a camera which is only used for projecting the image.
• Position center: If this is checked the image is positioned relative to its centre.
• Position lower left: If this is checked the image is positioned relative to its lower left corner.
• Position: The position of the image.
• Size: This is the size in metres of the image. By default the image is 1m x 1m. The image is stretched or shrunk to fit this size.
• Image size (pixels): This shows the actual size in pixels of the image.

• Border blending: This parameter lets you soften the edge of the shader, perhaps to blend into underlying textures.
• Mask by shader: Check this to mask the image map using another shader. Whiter parts of the shader show more of the image map. Shades of grey control the opacity of the image map.
• Fit mask to this: If this is checked the masking shader is remapped to fit into the area of the image map shader.
• Invert mask: If this is checked the mask shader is inverted, i.e. light parts become dark and vice versa.

Additional tabs for Image Map Shader

• Image Map Shader - Flip, Repeat Tab

• Image Map Shader - Colour Tab

• Image Map Shader - Displacement Tab

• Image Map Shader - Effects Tab

Literally, to change the position of something. In graphics terminology to displace a surface is to modify its geometric (3D) structure using reference data of some kind. For example, a grayscale image might be taken as input, with black areas indicating no displacement of the surface, and white indicating maximum displacement. In Terragen 2 displacement is used to create all terrain by taking heightfield or procedural data as input and using it to displace the normally flat sphere of the planet.

A shader is a program or set of instructions used in 3D computer graphics to determine the final surface properties of an object or image. This can include arbitrarily complex descriptions of light absorption and diffusion, texture mapping, reflection and refraction, shadowing, surface displacement and post-processing effects. In Terragen 2 shaders are used to construct and modify almost every element of a scene.

A parameter is an individual setting in a node parameter view which controls some aspect of the node.