<function name="Begin" parent="mesh" type="libraryfunc"> <description> Starts constructing a new 3D mesh constructed from a given number of primitives in a given primitive format. ⤶ Begins creating or modifying a 3D mesh constructed from a given quantity and type of primitive 3D shapes such as triangles and quads. The resulting mesh can be stored in an <page>IMesh</page> if it is intended to be drawn multiple times or on multiple frames. </description> <realm>Client</realm> <args name="Building a Dynamic Mesh">⤶ <args name="Building an IMesh">⤶ <arg name="mesh" type="IMesh">⤶ The <page>IMesh</page> that the created mesh will be stored in.⤶ ⤶ If the mesh has already been built, it will instead have its existing verticies modified but cannot have the quantity of vertices changed.⤶ </arg>⤶ <arg name="primitiveType" type="number"> An enum that indicates what the format of the mesh's primitives will be. For a full list of the available options, see the <page>Enums/MATERIAL</page>. </arg> <arg name="primitiveCount" type="number"> The quantity of primitives this mesh will contain as a whole integer number. The total number of vertices must not exceed the limit of `32768`. The number of vertices created by each primitive will depend on the type of primitive used to construct the mesh. The expected value of this argument is dependent on the primitive type used. For a full list of the primitive counts expected by each primitive type, see <page>Enums/MATERIAL</page>. </arg> </args> ⤶ <args name="Building an IMesh">⤶ <arg name="mesh" type="IMesh">⤶ The <page>IMesh</page> that the created mesh will be stored in.⤶ </arg>⤶ ⤶ <args name="Building a Dynamic Mesh">⤶ <arg name="primitiveType" type="number"> An enum that indicates what the format of the mesh's primitives will be. For a full list of the available options, see the <page>Enums/MATERIAL</page>. </arg> <arg name="primitiveCount" type="number"> The quantity of primitives this mesh will contain as a whole integer number. The total number of vertices must not exceed the limit of `32768`. The number of vertices created by each primitive will depend on the type of primitive used to construct the mesh. The expected value of this argument is dependent on the primitive type used. For a full list of the primitive counts expected by each primitive type, see <page>Enums/MATERIAL</page>. </arg> </args> </function> <example> <description> Draws a triangle near Vector( 0, 0, 0 ) in the map using a dynamic mesh, a dynamic mesh is good for animated meshes, or otherwise frequently changed rendered meshes. </description> <code> local mat = Material( "editor/wireframe" ) -- The material (a wireframe) local verts = { -- A table of 3 vertices that form a triangle { pos = Vector( 0, 0, 0 ), u = 0, v = 0 }, -- Vertex 1 { pos = Vector( 10, 0, 0 ), u = 1, v = 0 }, -- Vertex 2 { pos = Vector( 10, 10, 0 ), u = 1, v = 1 }, -- Vertex 3 } hook.Add( "PostDrawOpaqueRenderables", "MeshLibTest", function() render.SetMaterial( mat ) -- Apply the material mesh.Begin( MATERIAL_TRIANGLES, 1 ) -- Begin writing to the dynamic mesh for i = 1, #verts do mesh.Position( verts[i].pos ) -- Set the position mesh.TexCoord( 0, verts[i].u, verts[i].v ) -- Set the texture UV coordinates mesh.AdvanceVertex() -- Write the vertex end mesh.End() -- Finish writing the mesh and draw it end ) </code> </example> <example> <description>Draws a triangle near Vector( 0, 0, 0 ) in the map using a static mesh, that is, a mesh that is only created once, which is good for performance. </description> <code> local mat = Material( "editor/wireframe" ) -- The material (a wireframe) local obj = Mesh() -- Create the IMesh object local verts = { -- A table of 3 vertices that form a triangle { pos = Vector( 0, 0, 0 ), u = 0, v = 0 }, -- Vertex 1 { pos = Vector( 10, 0, 0 ), u = 1, v = 0 }, -- Vertex 2 { pos = Vector( 10, 10, 0 ), u = 1, v = 1 }, -- Vertex 3 } mesh.Begin( obj, MATERIAL_TRIANGLES, 1 ) -- Begin writing to the static mesh for i = 1, #verts do mesh.Position( verts[i].pos ) -- Set the position mesh.TexCoord( 0, verts[i].u, verts[i].v ) -- Set the texture UV coordinates mesh.AdvanceVertex() -- Write the vertex end mesh.End() -- Finish writing to the IMesh hook.Add( "PostDrawOpaqueRenderables", "MeshLibTest", function() render.SetMaterial( mat ) -- Apply the material obj:Draw() -- Draw the mesh end ) </code> </example>