![]() ![]() The above stream is not enough to actually draw anything you must also tell OpenGL how to interpret this stream. If we render with the above attribute array, but selected by the index list, OpenGL will receive the following stream of vertex attribute data: Let's say we have the following index list: However, you can also specify another list of indices that will select which vertices to use and in which order. If you use the above array as a stream, OpenGL will receive and process these three vertices in order (left-to-right). Let's say you have the following array of arrays containing 3d position data belonging to 3 vertices: The indices control what order the vertices are received in, and indices can specify the same array element more than once. You can generate a stream in the array's order, or you can use a list of indices to define the order. There are two ways of rendering with arrays of vertices. The order of vertices in the stream is very important this order defines how OpenGL will process and render the Primitives the stream generates. Note that these arrays are a bit more flexible than C arrays, but overall work the same way. All of these arrays must have the same number of elements. This set of attributes defines what values the vertex stream must provide to properly render with this shader.įor each attribute in the shader, you must provide an array of data for that attribute. The VS's user-defined input variables defines the list of expected Vertex Attributes for that shader, where each attribute is mapped to each user-defined input variable. ![]() In order to render at all, you must be using a shader program or program pipeline which includes a Vertex Shader. ![]() Submitting vertex data for rendering requires creating a stream of vertices, and then telling OpenGL how to interpret that stream. ![]()
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