Provides a convenient way to describe a primitive, such as a single triangle strip or a triangle fan, that will internally allocate the necessary AttributeBuffer storage, describe the position, texture coordinate and color attributes with Attribute<!-- -->s and upload your data.
For example to draw a convex polygon with texture mapping and a linear gradient you can do:
CoglVertexP2T2C4 triangle[] =
{
{ 0, 300, 0.0, 1.0, 0xff, 0x00, 0x00, 0xff},
{ 150, 0, 0.5, 0.0, 0x00, 0xff, 0x00, 0xff},
{ 300, 300, 1.0, 1.0, 0xff, 0x00, 0x00, 0xff}
};
prim = cogl_primitive_new_p2t2c4 (COGL_VERTICES_MODE_TRIANGLE_FAN,
3, triangle);
cogl_primitive_draw (prim);
The value passed as data.length
is initially used to determine how much can be read from data
but it will also
be used to update the Primitive <structfield>n_vertices</structfield> property
as if set_n_vertices were called. This property defines the number of
vertices to read when drawing.
<note>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). You should pass the cogl_texture_no_slicing flag to all textures that might be used while drawing with this API. 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)</note>
context |
A Context |
mode |
A VerticesMode defining how to draw the vertices |
data |
(type Cogl.VertexP2T2C4): An array of VertexP2T2C4 vertices |
n_vertices |
The number of vertices to read from |
A newly allocated Primitive with a reference of 1. This can be freed using |