Predefined Materials

Example:

vec_set(mtl_model.ambient_blue,vector(0,0,255));
// gives all models a reddish tint by reflecting only the red part of static lights

Predefined Surface Shaders

The mtlFX.c library in the code subfolder contains a library of predefined surface shaders. All shaders can be examined and edited in the Shader Viewer. For using a surface shader, include mtlFX.c in your main script, assign the shader action to the entity, and adjust the entity skills and material properties that serve as shader parameters.

Compared to external shaders, the library shaders are preferable because they are a) very fast, and b) work in a large range of situations. The following standard surface shaders and materials are available:

The Lights column indicates the number of simultaneously supported lights per mesh, and the Lightmap column indicates whether the shader also supports lightmaps on the second skin of blocks, models, or terrain. All shaders require shader model 2.0. For details about the shaders please see the comments inside mtlFX.c.

*SM: Supports a specular map on the texture alpha channel. A specular map determines the 'shinyness' of the texture. On alpha = 100 the texture is shiny, on alpha = 0 the texture is matt. If the texture has no alpha channel, 100% shinyness is assumed.

*NM: Supports a normal map on the second or third skin, dependent on whether a lightmap is used. A normal map is a RGB texture that determines the three components of a local surface normal. It is usually generated by a special tool in a high polygon model editor, or converted from a height map.

*HM: Requires a depth map on the alpha channel of the normal map. A depth map determines a height modulation of the surface. On alpha = 100 the surface has a dent, on alpha = 0 it has a bump. The depth map uses the same coordinates as the normal map. Without it, the shader won't work.

*LM: Supports a lightmap either on the second skin of a block, or on the second coordinate set of a model, or assigned to entities' lightmap pointer. A lightmap is a RGB texture that determines local light and shadow modulation of the surface, and uses normally a different resolution and UV coordinate set than the texture. If the object has no lightmap, a 100% white light modulation is assumed. Shaders that support lightmaps can be assigned to models as well as to level geometry.

*LOD: Shader disabled above the given LOD step, for speed reasons.

Remarks

• The predefined shaders can be adjusted through material properties, the entity albedo and alpha variables, and up to four variables in the 0..100 range that can be either set in skill1..skill4 in WED (when directly assigning the shader action), or as floatv in skill41..skill44 (when setting the shader material in an entity action). The meaning of the 4 variables depends on the shader, and can be tested and adjusted with the four sliders in the Shader Viewer.
• Many shaders support only a limited number of lights (2 or 3) for speed reasons. If an object is in the range of more lights, dynamic light sorting can cause a sudden change of lighting especially when far-away lights (such as the sun) have a higher brightness than close lights. Position your dynamic lights cleverly when using light-limited shaders.
• You can edit any of the predefined shaders and adapt it to any special requirements of your project. For this, copy the .fx shader file from the code folder into your work folder, and edit it with SED. Use the AUTORELOAD flag for observing your changes immediately in the level.
• For editing a shader and observing the results in real time, copy the .fx shader code from the code folder into the projects\shadertest folder, and edit it with SED. If the same shader is selected in the Shader Viewer, the results can be immediately observed whenever the shader code is saved. For adding a new shader, copy mtlFX.c into the projects\shadertest folder, and add a new material and a new .fx effect just like the already defined shaders.
• Realtime reflection scripts set NOFLAG1 for the mirror view, thus suppressing all objects with FLAG1 in the mirror. This can be used for improving the frame rate by setting FLAG1 for all object details that don't need to be reflected.
• For applying a lightmap-supporting shader to a block or group in WED, look under Apply Shaders. Shader variables for level block shaders can be set globally through skill41..skill44 of the level_ent entity.
• Shaders are only compiled when they are used, i.e. assigned to an entity. This reduces the engine startup time when the shader library is included. For early compiling shaders, use ent_preload or preload_mode. For precompiling all used shaders, use the -fxo command line option.

For adding a shader to an entity action in a lite-C script, set the 4 shader variables (if applicable) and the material at the beginning of the entity action:

Example (lite-C):

#include <mtlFX.c>
...
action toon_warrior()
{
  my.skill41 = floatv(50);  // Shadow
  my.skill42 = floatv(50);  // Edgewidth
  my.skill43 = floatv(50);  // Threshold
  my.skill44 = floatv(50);  // Smooth
  my.material = mtl_toon;
  ...
}

mtl_terraintex

The game editor GED automatically creates and assigns the textures when you directly paint onto the terrain. If you've created them in a different program, open the terrain in MED and assign texture1 to the first skin, texture2 to the second, and so on. Every texture requires a separate render pass, thus don't use too many of them. When 3 or more textures are assigned to a terrain, MED Engine Preview automatically displays the terrain with the mtl_terraintex shader.

mtl_lightcount

For temporarily replacing any of the predefined shaders by the light count shader, copy mtlFX.c in your work folder, edit the material definition and temporarily replace the original effect = "....fx"; line by effect = "lightcount.fx";.

See also:

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