Materials and textures

The SpeedTree pipeline is built for flexibility which can add a little more complexity to the export/import process. When an .stsdk file is exported from the SpeedTree Modeler application, the user selects which texture packer will be used. References:

• Exporting an .stsdk file from the Modeler. Users will have multiple format options upon game export, but be sure to use .stsdk for the SpeedTree Runtime SDK.
• Texture packing. The Modeler ships with a few samples, including the one used for the SpeedTree reference application.

An .stsdk file contains only texture filenames, not the actual texture data.

The following code illustrates how to load an .stsdk file and query its materials and associated textures.

#include "SpeedTree/Core/Core.h"

// speedtree types
using SpeedTree::st_uint32;
using SpeedTree::st_float16;
using SpeedTree::st_uint8;
using SpeedTree::st_uint16;

void MyErrorCallback(const char* pMsg) { fprintf(stderr, "SpeedTree Runtime SDK Error: [%s]\n", pMsg); }

void ShowMaterialAccess(const char* pFilename)
{
    // set up error callback
    SpeedTree::Callbacks::Error( ) = MyErrorCallback;

    // parameters needed to load
    SpeedTree::CCore::SLoadConfig sLoadConfig;
    sLoadConfig.m_strFilename = pFilename;
    sLoadConfig.m_bGrassModel = false;

    // create a model to hold and read the stsdk file
    SpeedTree::CCore cModel;
    if (cModel.LoadTree(sLoadConfig))
    {
        st_uint32 uiNumMaterials = cModel.Materials( ).Count( );
        for (st_uint32 i = 0; i < uiNumMaterials; ++i)
        {
            // get next material, prine name
            SpeedTree::CFileMaterial cMaterial = cModel.Materials( )[i];
            printf("material[%d] \"%s\"\n", i, cMaterial.Name( ).Data( ));

            // each material has keeps its own count, but the Runtime SDK is configured to
            // copy no more than ST_MAX_NUM_STSDK_MATERIAL_MAPS
            for (st_uint32 j = 0; j < cMaterial.Maps( ).Count( ) && j < ST_MAX_NUM_STSDK_MATERIAL_MAPS; ++j)
            {
                printf("\tmap[%d] filename: \"%s\"\n", j, cMaterial.Maps( )[j].Path( ).Data( ));
            }

            // the Runtime SDK does not have an enumeration defining what type of material each map defines
            // (e.g. 0 = ALBEDO, 1 = NORMAL) because this is determined by the texture packer in the 
            // Modeler application; each user/team sets their own pipeline
        }
    }
}