When associating indices with a CoglPrimitive you are now forced to
specify the number of indices that should be read when drawing.
It's easy to forget to call cogl_primitive_set_n_vertices() after
associating indices with a primitive (and anyway you can see that someone
could be led to believe Cogl can determine that implicitly somewhow) so
this should avoid a lot of mistakes with using the API.
We'd expect that setting indices and updating the n_vertices property
would go hand in hand 99% of the time anyway so this change should
be more convenient as well as less error prone.
This patch adds some documentation for cogl_primitive_set_indices and
cogl_primitive_get/set_n_vertices. It also tries to clarify how the
CoglPrimitive:n_vertices property is updated and what that property
means in relation to other functions too.
https://bugzilla.gnome.org/show_bug.cgi?id=661019
Reviewed-by: Neil Roberts <neil@linux.intel.com>
For the first iteration of the CoglAttribute API several of the new
functions accepted a pointer to a NULL terminated list of CoglAttribute
pointers - probably as a way to reduce the number of arguments required.
This style isn't consistent with existing Cogl APIs though and so we now
explicitly pass n_attributes arguments and don't require the NULL
termination.
This is part of a broader cleanup of some of the experimental Cogl API.
One of the reasons for this particular rename is to switch away from
using the term "Array" which implies a regular, indexable layout which
isn't the case. We also want to have a strongly implied relationship
between CoglAttributes and CoglAttributeBuffers.
This is part of a broader cleanup of some of the experimental Cogl API.
One of the reasons for this particular rename is to reduce the verbosity
of using the API. Another reason is that CoglVertexArray is going to be
renamed CoglAttributeBuffer and we want to help emphasize the
relationship between CoglAttributes and CoglAttributeBuffers.
We have a bunch of experimental convenience functions like
cogl_primitive_p2/p2t2 that have corresponding vertex structures but it
seemed a bit odd to have the vertex annotation e.g. "P2T2" be an infix
of the type like CoglP2T2Vertex instead of be a postfix like
CoglVertexP2T2. This switches them all to follow the postfix naming
style.
This adds convenience primitive constructors named like:
cogl_primitive_new_p3 or
cogl_primitive_new_p3c4 or
cogl_primitive_new_p3t2c4
where the letters correspond to the interleved vertex attributes layouts
such as CoglP3Vertex which is a struct with 3 float x,y,z members for
the [p]osition, or CoglP3T2C4Vertex which is a struct with 3 float x,y,z
members for the [p]osition, 2 float s,t members for the [t]exture
coordinates and 4 unsigned byte r,g,b,a members for the [c]olor.
The hope is that people will find these convenient enough to replace
cogl_polygon.
A CoglPrimitive is a retainable object for drawing a single primitive,
such as a triangle strip, fan or list.
CoglPrimitives build on CoglVertexAttributes and CoglIndices which
themselves build on CoglVertexArrays and CoglIndexArrays respectively.
A CoglPrimitive encapsulates enough information such that it can be
retained in a queue (e.g. the Cogl Journal, or renderlists in the
future) and drawn at some later time.
