Constructor

CoglPrimitivenew_p2t2

Declaration [src]

CoglPrimitive*
cogl_primitive_new_p2t2 (
  CoglContext* context,
  CoglVerticesMode mode,
  int n_vertices,
  const CoglVertexP2T2* data
)

Description [src]

Provides a convenient way to describe a primitive, such as a single triangle strip or a triangle fan, that will internally allocate the necessary CoglAttributeBuffer storage, describe the position and texture coordinate attributes with CoglAttributes and upload your data.

For example to draw a convex polygon with texture mapping you can do:

CoglVertexP2T2 triangle[] =
{
  { 0,   300,  0.0, 1.0},
  { 150, 0,    0.5, 0.0},
  { 300, 300,  1.0, 1.0}
};
prim = cogl_primitive_new_p2t2 (COGL_VERTICES_MODE_TRIANGLE_FAN,
                                3, triangle);
cogl_primitive_draw (prim);

The value passed as n_vertices is initially used to determine how much can be read from data but it will also be used to update the CoglPrimitive n_vertices property as if cogl_primitive_set_n_vertices() were called. This property defines the number of vertices to read when drawing.

The primitive API doesn’t support drawing with sliced textures (since switching between slices implies changing state and so that implies multiple primitives need to be submitted). If your hardware doesn’t support non-power of two textures (For example you are using GLES 1.1) then you will need to make sure your assets are resized to a power-of-two size (though they don’t have to be square).

Parameters

context

Type: CoglContext

A CoglContext.

The data is owned by the caller of the function.
mode

Type: CoglVerticesMode

A CoglVerticesMode defining how to draw the vertices.

n_vertices

Type: int

The number of vertices to read from data and also the number of vertices to read when later drawing.

data

Type: An array of None

An array of CoglVertexP2T2 vertices.

The length of the array is specified in the n_vertices argument.
The data is owned by the caller of the function.

Return value

Type: CoglPrimitive

A newly allocated CoglPrimitive with a reference of 1. This can be freed using g_object_unref().

The caller of the function takes ownership of the data, and is responsible for freeing it.