VertexArray Class Reference

#include <VertexArray.h>

Inheritance diagram for VertexArray:

List of all members.

Public Member Functions
void	setAttribute (const char *name, u32 offset, u32 length, AttributeType_t type, bool normalize_int=false)
void	setIndexArray (void *new_array, u32 type_size, u32 n)
void	setArray (void *new_array, u32 n)
u32	getLength ()
u32	getStride ()
u32	getAttributeCount ()
Attribute_t *	getAttribute (u32 i)
Attribute_t *	getAttribute (char *name)
PrimitiveLayout_t	getPrimitiveLayout ()
u32	getIndexTypeSize ()
u32	getIndexLength ()
AttributeUsage_t	getUsage ()
AttributeUsage_t	getIndexUsage ()
void *	getHandle ()
void	setHandle (void *nhandle)
Protected Member Functions
AABox	getBoundingBox ()
Friends
class	SceneGraph
class	Geometry

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Detailed Description

Vertex array. Inherits from Resource.

This is an array of vertices that is used in conjunction with an index array. The index array points to vertex attributes from this array, and these will be used to construct triangles with accompanying data.

A vertex array should at least contain an attribute that specifies the position of a vertex. Other common properties are normals, color and texture coordinates.

The vertex array is organized in a array of structs-manner, as opposed to a struct of arrays. The difference is illustrated below with a vertex array containing position, normal and color data.

 *                       Vertex attributes
 *
 *   Struct of arrays (not used)       Array of structs
 *   (SOA)                             (AOS)
 *
 *    Vertex[0] Position.x              Vertex[0] Position.x       ^
 *    Vertex[0] Position.y              Vertex[0] Position.y       | S
 *    Vertex[0] Position.z              Vertex[0] Position.z       | t
 *    Vertex[1] Position.x              Vertex[0] Normal.x         | r
 *    Vertex[1] Position.y              Vertex[0] Normal.y         | i
 *    Vertex[1] Position.z              Vertex[0] Normal.z         | d
 *     ...                              Vertex[0] Color.r          | e
 *    Vertex[0] Normal.x                Vertex[0] Color.g          |
 *    Vertex[0] Normal.y                Vertex[0] Color.b          |
 *    Vertex[0] Normal.z                Vertex[0] Color.a          v
 *    Vertex[1] Normal.x                Vertex[1] Position.x
 *    Vertex[1] Normal.y				Vertex[1] Position.y
 *    Vertex[1] Normal.z				Vertex[1] Position.z
 *     ...								Vertex[1] Normal.x
 *     ...								Vertex[1] Normal.y
 *    Vertex[0] Color.r					Vertex[1] Normal.z
 *    Vertex[0] Color.g					Vertex[1] Color.r
 *    Vertex[0] Color.b					Vertex[1] Color.g
 *    Vertex[0] Color.a					Vertex[1] Color.b
 *    Vertex[1] Color.r					Vertex[1] Color.a
 *    Vertex[1] Color.g                  ...
 *    Vertex[1] Color.b
 *    Vertex[1] Color.a
 *     ...
 *
 * 

In this example, for the AOS the stride = 10 * size(f32), since the data type repeats after every 10 entries and (in this example) we assume that each struct member is a 32-bit float.

The offset for the "Normal" attribute in this example is 3, since it's three entries in from the beginning of the array. It's length is 3, since it has three components (x, y, z).

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Member Function Documentation

void VertexArray::setAttribute	(	const char *	name,
		u32	offset,
		u32	length,
		AttributeType_t	type,
		bool	normalize_int = false
	)

Parameters:

name	Name of the attribute. This must comply with the vertex attribute names expected further down in the rendering pipeline (as defined by the renderer and shader program.)
offset	Offset, in bytes, to the first entry in the struct/array.
length	Number of components in this attribute. This is _NOT_ given in bytes, as the type-argument multiplied with the length reveals the total byte length.
normalize_int	This is only valid for int#-variants. If this is true values will be scaled to the interval [0, 1] in the renderer, otherwise no scaling will occur.

void VertexArray::setIndexArray	(	void *	new_array,
		u32	type_size,
		u32	n
	)

Parameters:

n

The number of indices in the index array. (_NOT_ the number of triangles you expect to be created). The layout argument specified in the constructor will be used by this index array. It's indices point to entries in the attached vertex attribute array. It's safe to delete the incoming index array after calling this function.

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The documentation for this class was generated from the following files:

• C:/Users/Malacka/Desktop/Magnus/RenderChimp/src/VertexArray.h
• C:/Users/Malacka/Desktop/Magnus/RenderChimp/src/VertexArray.cpp