Type Function Library display.* Return value ShapeObject Revision Release 2022.3683 Keywords shape, mesh, vector object See also Shapes — Paths, Fills, Strokes (guide) Display Objects (guide)
Draws a mesh shape by providing vertices of the shape. The local origin is at the center of the mesh and the anchor point is initialized to this local origin.
display.newMesh( [parent,] [x, y,] options ) display.newMesh( options )
GroupObject. An optional display group in which to insert the mesh.
Numbers. The location of the object relative to its parent.
Table. Table containing options for the mesh — see the next section for details.
The options
table accepts the following parameters for the mesh:
Array. An array of x and y coordinates of vertices forming the mesh. Meshes are built with these vertices depending on the mode
parameter.
GroupObject. An optional display group in which to insert the mesh. If included here, this will override any parent
definition specified outside of the options
table.
Numbers. The location of the object relative to its parent. If included here, these will override any x
or y
definitions specified outside of the options
table.
String. String indicating how the mesh should be formed with the provided vertices. Default is "triangles"
. Acceptable values are "triangles"
, "strip"
, "fan"
, or "indexed"
. See Mesh Draw Modes below for a description of each mode.
Array. An array of indices required for mode
type of "indexed"
. For example, to mimic the behavior of the "strip"
mode, the value of this parameter could be { 1,2,3, 2,3,4, 3,4,5 }
Boolean. Convenience parameter with default of false
. If set to true
, the indices
array will be treated as a
Array. An array of u and v texture coordinates of vertices forming the mesh. If omitted or invalid, UVs will be automatically assigned based on normalized vertices
values. Texture coordinates are normalized coordinates where 0,0
is the 1,1
is the
Meshes with a mode
of "triangles"
or "indexed"
are formed with disjointed groups of three consecutive vertices. An example of a "triangles"
mode could have vertices with indices 1,2,3
, 4,5,6
, and 7,8,9
. Note, however, that the "triangles"
mode may result in duplicate vertices shared by several triangles — to avoid this, you can use the "indexed"
type and define an indices
table with indices pointing to the vertices used.
While these methods can be used to encode any mesh, they both have some duplication if a vertex is used by several triangles. In the case of "triangles"
, this is the vertices themselves. In the case of "indexed"
, this is the vertex indices. Duplicating indices is much cheaper because they're single integer numbers, not an entire vertex with coordinates and texture coordinates.
In some cases, this duplication can be avoided via the "strip"
or "fan"
mode (see below).
Meshes with a mode
of "strip"
are formed with three consecutive vertices. An example could have vertices with indices 1,2,3
, 2,3,4
, and 3,4,5
. For more information on this type, see here.
Meshes with a mode
of "fan"
are formed with an initial vertex and two ending vertices. An example could have vertices with indices 1,2,3
, 1,3,4
, and 1,4,5
. For more information on this type, see here.
Vertices will be visually shifted so that the center of the mesh will be at the origin of the object. This does not change values when accessing vertices.
The origin will not be adjusted to the center of the mesh when modifying the mesh.
When referencing the index
parameter of any method, you must point to an existing vertex.
If an invalid mesh is requested, this function will return nil
.
Setting the stroke for a mesh with mode
value of "triangles"
or "indices"
can impact performance if the mesh has a lot of vertices.
(Inherits properties from ShapeObject)
Shape objects have a path
property that exposes methods to manipulate the mesh. Most methods accept the index
parameter which is the Lua array index of the vertex in question (the first vertex would have an index of 1
). All arguments are numbers.
Sets the vertex with index index
to coordinates x
and y
:
object.path:setVertex( index, x, y )
Returns two numbers corresponding to a vertex's coordinates:
object.path:getVertex( index )
Sets the vertex with index index
to texture coordinates u
and v
:
object.path:setUV( index, u, v )
Returns two numbers corresponding to a vertex's texture coordinates:
object.path:getUV( index )
Returns two numbers corresponding to the horizontal and vertical offsets applied when moving the origin to the center of the mesh. You can offset the mesh object by these values to compensate for initial shift and get precise vertex positions in world coordinates.
object.path:getVertexOffset()
Note that a vertex with coordinates x
and y
will have world coordinates of mesh.x + x - offsetX
mesh.y + y - offsetY
0,0
into the previous object origin:
mesh:translate( mesh.path:getVertexOffset() )
Updates the mesh’s vertices
, uvs
and indices
:
object.path:update( options )
The options
table accepts the vertices
, uvs
and indices
for updating the mesh. These are all optional and can be excluded at will:
local options = { vertices = {}, uvs = {}, indices = {} } mesh.path:update( options )
local mesh = display.newMesh( { x = 100, y = 100, mode = "triangles", vertices = { 0,0, 50,0, 0,100, 0,100, 50,0, 100,100, 100,100, 50,0, 100,0 }, uvs = { 0,0, 0.5,0, 0,1, 0,1, 0.5,0, 1,1, 1,1, 0.5,0, 1,0 } }) mesh:translate( mesh.path:getVertexOffset() ) -- Translate mesh so that vertices have proper world coordinates mesh.fill = { type="image", filename="cat.png" } local vertexX, vertexY = mesh.path:getVertex( 3 ) mesh.path:setVertex( 3, vertexX, vertexY-10 )
local mesh = display.newMesh( { x = 100, y = 100, mode = "indexed", vertices = { 0,0, 0,100, 50,0, 100,100, 100,0 }, indices = { 1,2,3, 2,3,4, 3,4,5 } }) mesh:translate( mesh.path:getVertexOffset() ) -- Translate mesh so that vertices have proper world coordinates mesh.fill = { type="image", filename="cat.png" } local vertexX, vertexY = mesh.path:getVertex( 3 ) mesh.path:setVertex( 3, vertexX, vertexY-10 )
local mesh = display.newMesh( { x = 100, y = 100, mode = "strip", vertices = { 0,0, 0,100, 50,0, 100,100, 100,0 } }) mesh:translate( mesh.path:getVertexOffset() ) -- Translate mesh so that vertices have proper world coordinates mesh.fill = { type="image", filename="cat.png" } local vertexX, vertexY = mesh.path:getVertex( 3 ) mesh.path:setVertex( 3, vertexX, vertexY-10 )
local mesh = display.newMesh( { x = 100, y = 100, mode = "fan", vertices = { 50,0, 0,0, 0,100, 100,100, 100,0 } }) mesh:translate( mesh.path:getVertexOffset() ) -- Translate mesh so that vertices have proper world coordinates mesh.fill = { type="image", filename="cat.png" } local vertexX, vertexY = mesh.path:getVertex( 3 ) mesh.path:setVertex( 3, vertexX, vertexY-10 )