|type||The data type that this custom vertex data will hold (see the type constants listed below).|
|usage||The use that the data will get(see the usage constants listed below).|
This function permits you to use a custom data type for specific vertex format attributes as part of the new vertex format being created. The available values to use are defined by the data type constant that you choose, listed below:
Constant Description vertex_type_float1 A single floating point value vertex_type_float2 Two floating point values vertex_type_float3 Three floating point values vertex_type_float4 Four floating point values vertex_type_colour Four component values (r, g, b, a) vertex_type_ubyte4 Four component unsigned byte values (from 0 to 255)
The use that these constants will be put too also needs to be defined so that the values can be "bound" properly within the shader being created. This is necessary due to the fact that DX and OpenGL have different requirements so if you don't bind them properly, they won't come through right in the shader. The available usage constants that you can choose are listed below and those you use will depend on the specifics of the shader being created:
Constant Description vertex_usage_position position values (x, y, z) vertex_usage_colour colour values (r, g, b, a) vertex_usage_normal vertex normal values (nx, ny, nz) vertex_usage_textcoord UV coordinates (u, v) vertex_usage_blendweight the blendweight of the input matrix (for skeletal animation, for example) vertex_usage_blendindices the indices of the matrices to use (for skeletal animation, for example) vertex_usage_depth vertex depth buffer value vertex_usage_tangent tangent values vertex_usage_binormal binormal values vertex_usage_fog fog values vertex_usage_sample sampler index
Note that the vertex_format_add_custom() function only supports vertex_usage_position, vertex_usage_colour, vertex_usage_normal and vertex_usage_textcoord when using GLSL shaders. These will map to the shader attributes in_Position, in_Colour[0 - ...], in_Normal respectively (anything that is not one of these three attributes - eg: texture coordinates - can be mapped to any attribute you define).
my_format = vertex_format_end();
The above code will create a new vertex format with just texture and 3 custom floating point values for position. It is then stores the format id in the variable "my_format".