gdk::graphics::model_data Class Reference

vertex data stored in system memory. More...

#include <model_data.h>

Public Types
enum class	primitive_mode { triangles }
using	attribute_collection_type = string_keyed<attribute_data>
using	index_value_type = unsigned short

Public Member Functions
primitive_mode	get_primitive_mode () const
	get the primitive mode
const std::vector< index_value_type > &	indexes () const
	the order the vertices are drawn in, empty if they are drawn in storage order
bool	indexed () const
	does this model name its vertices in an explicit order?
void	set_indexes (std::vector< index_value_type > aIndexes)
	draw the vertices in this order rather than in the order they are stored
const attribute_collection_type &	attributes () const
	get collection of all attribute data
const attribute_data &	get_attribute_data (std::string_view aAttributeName) const
	get attribute data by name, e.g: "a_Position"
attribute_data &	get_attribute_data (std::string_view aAttributeName)
	get attribute data by name, e.g: "a_Position"
void	clear ()
	clears all state from this model_data instance
void	transform (const std::string &aPositionAttributeName, const vector3_type &aPos, const quaternion_type &aRot={}, const vector3_type &aSca={1, 1, 1})
	applies a transformation to a 3 component attribute
void	transform (const std::string &aPositionAttributeName, const matrix4x4_type &aTransform)
	applies a transformation matrix to a 3 component attribute
void	transform (const std::string &aUVAttributeName, const vector2_type &aPos, const float aRotation=0, const vector2_type &aSca={1, 1})
	applies a transformation to a 2 component attribute
void	sort_by_nearest_triangle (const vector3_type &aObserverWorldPosition, matrix4x4_type aEntityInstanceWorldMatrix, std::string_view aPositionAttributeName="a_Position")
void	sort_by_furthest_triangle (const vector3_type &aObserverWorldPosition, matrix4x4_type aEntityInstanceWorldMatrix, std::string_view aPositionAttributeName="a_Position")
void	push_back (const model_data &other)
	append a different model_data to this model_data
void	overwrite (const std::size_t index, const model_data &other)
	overwrite a section of vertex data using another vertex data instance
void	overwrite (std::string_view aAttributeName, const std::size_t vertexOffset, const model_data &other)
	overwrite a section of a single attribute in the vertex data
std::size_t	vertex_count () const
	get number of verticies in the data
model_data	operator+ (const model_data &aData)
	create a new instance that is a concatenation of two separate datas
model_data &	operator+= (const model_data &other)
model_data &	operator= (model_data &&other)=default
	support move semantics
	model_data (model_data &&)=default
	support move semantics
	model_data (const model_data &)=default
	support copy semantics
model_data &	operator= (const model_data &other)=default
	support copy semantics
	model_data ()=default
	default inited model_data is very useful for procedurally generated data
	model_data (attribute_collection_type &&aAttributeData)
	model_data (attribute_collection_type &&aAttributeData, std::vector< index_value_type > &&aIndexes)

Static Public Member Functions
static model_data	make_quad ()
	creates model data for a unit sized quad with position and uv data

Detailed Description

vertex data stored in system memory.

vertex data is comprised of a collection of attributes, which in turn are a collection of components

Constructor & Destructor Documentation

model_data() [1/2]

gdk::graphics::model_data::model_data

(

attribute_collection_type &&

aAttributeData

)

Exceptions

exception

if an attribute is not whole vertices, or the attributes count different numbers of them

model_data() [2/2]

gdk::graphics::model_data::model_data	(	attribute_collection_type &&	aAttributeData,
		std::vector< index_value_type > &&	aIndexes )

Exceptions

exception

if an index is past the end of aAttributeData.

See also

set_indexes

Member Function Documentation

indexes()

const std::vector< index_value_type > & gdk::graphics::model_data::indexes

(

)

const

the order the vertices are drawn in, empty if they are drawn in storage order

A model with indices is drawn with glDrawElements and one without with glDrawArrays. Indexing lets a vertex shared by several triangles be stored once, which for a typical closed surface is about a third of the vertices a triangle soup needs.

operator+=()

model_data & gdk::graphics::model_data::operator+=

(

const model_data &

other

)

append a copy of different model_data to this model_data

Warning

must be same format

overwrite() [1/2]

void gdk::graphics::model_data::overwrite	(	const std::size_t	index,
		const model_data &	other )

overwrite a section of vertex data using another vertex data instance

formats must match exactly, the incoming data cannot write past the end of this

overwrite() [2/2]

void gdk::graphics::model_data::overwrite	(	std::string_view	aAttributeName,
		const std::size_t	vertexOffset,
		const model_data &	other )

overwrite a section of a single attribute in the vertex data

the vertex data must contain an attribute with the given name and that attribute must have the same # of components

push_back()

void gdk::graphics::model_data::push_back

(

const model_data &

other

)

append a different model_data to this model_data

Nothing changes when it throws. The appended indices are offset so that they still name the appended vertices. If only one of the two is indexed, the other is given the indices it implies, because the result has to be one thing or the other.

set_indexes()

void gdk::graphics::model_data::set_indexes

(

std::vector< index_value_type >

aIndexes

)

draw the vertices in this order rather than in the order they are stored

Exceptions

exception

if an index is past the end of the vertex data. Out of range indices are undefined behaviour in gl: they usually draw garbage or take the driver down, and they never say why, so they are refused here where the cause is still visible.

An empty list removes the indices, returning the model to storage order.

sort_by_furthest_triangle()

void gdk::graphics::model_data::sort_by_furthest_triangle	(	const vector3_type &	aObserverWorldPosition,
		matrix4x4_type	aEntityInstanceWorldMatrix,
		std::string_view	aPositionAttributeName = "a_Position" )

sorts verticies from furthest to nearest based on the distance between the centroid of the triangles they form and a given position in world space

sort_by_nearest_triangle()

void gdk::graphics::model_data::sort_by_nearest_triangle	(	const vector3_type &	aObserverWorldPosition,
		matrix4x4_type	aEntityInstanceWorldMatrix,
		std::string_view	aPositionAttributeName = "a_Position" )

sorts verticies from nearest to furthest based on the distance between the centroid of the triangles they form and a given position in world space

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

• /home/runner/work/gdk-graphics/gdk-graphics/data/include/gdk/graphics/model_data.h