I think it's:
4 = block type... ie: the number that goes in the grid cell (as you said)
"stone" = the unique name for the block type
"Stone" = the display name for the type... the one that appears in the tool view
MaterialType.STONE = the actual properties of the "material type", ie: mass, hardness, etc. It also controls what sound effect is used when walking on it and stuff.
0 = the group number. It controls how how faces are merged.
new CubeFactory(4) = the factory that actually creates the geometry using texture/material type "4" (ie: the bumpy stone texture) and it uses it for all of the sides. It's only coincidence that this number is the same as the block type.
As to "Why does it look so easy?" because I wrote addToolGroup(), addType(), MaterialType, and CubeFactory for you. They are doing all of the work and this line is only associating things together. And it's about the simplest case there is.
Things do get more complicated, after all:
addType( 28, "stone-pillar-se", "Stone Pillar", MaterialType.STONE ) {
fromTemplate( "pillar-se" ) { remapMaterials( 0:4 ) }
}
Which is referring to the pillar-se template:
addTemplate( "pillar-se" ) {
fromTemplate( "pillar-nw" ) {
rotate(180);
}
up() {
quad(0) { retexture(Direction.UP) }
}
down() {
quad(0) { retexture(Direction.DOWN) }
}
}
Which itself is a 180 degree rotation of the pillar-nw template:
addTemplate( "pillar-nw" ) {
Vector3f oMin = new Vector3f( 0, 0, 0 );
Vector3f oMax = new Vector3f( 0.5f, 0.5f, 1 );
collider( new CubeCollider( oMin, oMax ) );
Vector3f min = oMin.subtract( 0.5f, 0.5f, 0.5f );
Vector3f max = oMax.subtract( 0.5f, 0.5f, 0.5f );
north( ShapeIndex.getRect(oMin.x, oMin.z, oMax.x, oMax.z) ) {
quad {
material(0);
vertex( max.x, min.y, min.z ) {
texture( 0, 0 );
}
vertex( min.x, min.y, min.z ) {
texture( 1, 0 );
}
vertex( min.x, min.y, max.z ) {
texture( 1, 1 );
}
vertex( max.x, min.y, max.z ) {
texture( 0, 1 );
}
}
}
internal( Direction.SOUTH ) { //south( ShapeIndex.getRect(min.x, min.z, max.x, max.z) ) {
quad {
material(0);
vertex( min.x, max.y, min.z ) {
texture( 0, 0 );
}
vertex( max.x, max.y, min.z ) {
texture( 1, 0 );
}
vertex( max.x, max.y, max.z ) {
texture( 1, 1 );
}
vertex( min.x, max.y, max.z ) {
texture( 0, 1 );
}
}
}
west( ShapeIndex.getRect(oMin.y, oMin.z, oMax.y, oMax.z) ) {
quad {
material(0);
vertex( min.x, min.y, min.z ) {
texture( 0, 0 );
}
vertex( min.x, max.y, min.z ) {
texture( 1, 0 );
}
vertex( min.x, max.y, max.z ) {
texture( 1, 1 );
}
vertex( min.x, min.y, max.z ) {
texture( 0, 1 );
}
}
}
internal( Direction.EAST ) {
quad {
material(0);
vertex( max.x, max.y, min.z ) {
texture( 0, 0 );
}
vertex( max.x, min.y, min.z ) {
texture( 1, 0 );
}
vertex( max.x, min.y, max.z ) {
texture( 1, 1 );
}
vertex( max.x, max.y, max.z ) {
texture( 0, 1 );
}
}
}
up( ShapeIndex.getRect(oMin.x, oMin.y, oMax.x, oMax.y) ) {
quad {
material(0);
vertex( min.x, max.y, max.z ) {
texture( 0, 0 );
}
vertex( max.x, max.y, max.z ) {
texture( 1, 0 );
}
vertex( max.x, min.y, max.z ) {
texture( 1, 1 );
}
vertex( min.x, min.y, max.z ) {
texture( 0, 1 );
}
}
}
down( ShapeIndex.getRect(oMin.x, oMin.y, oMax.x, oMax.y) ) {
quad {
material(0);
vertex( max.x, max.y, min.z ) {
texture( 1, 1 );
}
vertex( min.x, max.y, min.z ) {
texture( 0, 1 );
}
vertex( min.x, min.y, min.z ) {
texture( 0, 0 );
}
vertex( max.x, min.y, min.z ) {
texture( 1, 0 );
}
}
}
}
These are more complicated to explain.
