mesh

FreeBodyEngine.graphics.gl33.mesh

GLMesh(attributes, indices=None, primitive=None, index_type=None, usage=None)

Bases: Mesh

The GL 3.3 implementation of Mesh: owns a real VAO, one VBO per vertex attribute, and an optional EBO for indexed drawing. Maps the abstract PrimitiveType onto the actual GL draw-mode enum once at construction (_render_mode) rather than re-resolving it on every draw().

Generates the VAO and, if indices is given, the EBO (VBOs themselves are created lazily per-attribute in upload()), resolves primitive to its GL draw-mode enum, and immediately calls upload() to push the mesh's initial data to the GPU.

ebo = glGenBuffers(1) if indices is not None else None instance-attribute

vao = glGenVertexArrays(1) instance-attribute

vbos = {} instance-attribute

destroy()

Deletes every attribute VBO, the EBO if this mesh has one, and the VAO itself, releasing all of this mesh's GPU resources.

draw()

Issues the draw call: glDrawElements against the EBO if this mesh has indices, else glDrawArrays over a vertex count derived from the first attribute's raw array length divided by 3 (i.e. this non-indexed path assumes that first attribute is 3 components wide, such as a "verticies" vec3 channel).

upload()

(Re)creates one VBO per entry in self.attributes and uploads its data, wiring each up as a sequential vertex attribute starting at location 0 in self.attributes' iteration order - so the order attributes are inserted into that dict is exactly the order the matching shader's in locations must line up with. Also uploads self.indices into the EBO if this mesh has one, recording its GL index-element type (gl_index_type) for draw() to use.