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gh_vb library

Description

gh_vb is a module that manages OpenGL vertex buffers. gh_vb allows to create, set values and render simple vertex buffers.

Number of functions: 16

gh_vb.bind ()
gh_vb.create ()
gh_vb.draw_lines ()
gh_vb.draw_points ()
gh_vb.draw_triangles ()
gh_vb.kill ()
gh_vb.map ()
gh_vb.set_value_1f ()
gh_vb.set_value_1ui ()
gh_vb.set_value_2f ()
gh_vb.set_value_3f ()
gh_vb.set_value_4f ()
gh_vb.set_value_4x4f ()
gh_vb.set_vertex_attrib_data ()
gh_vb.unbind ()
gh_vb.unmap ()

bind

Description

Binds a vertex buffer.

Syntax

gh_vb.bind( vb_id )

Languages

Parameters

vb_id [ID]: vertex buffer identifier

Return Values

This function has no return value(s).

Code sample


gh_vb.bind(vb_id)

create

Description

Creates a vertex buffer.

Syntax

vb_id = gh_vb.create( buff_size, num_vertex_attribs )

Languages

Parameters

buff_size [INTEGER]: size of the vertex buffer in bytes
num_vertex_attribs [INTEGER]: number of vertex attribs

Return Values

vb_id [ID]: vertex buffer identifier

Code sample


vb_id = gh_vb.create(buffer_size, num_vertex_attribs)

draw_lines

Description

Draws lines from a vertex buffer.

Syntax

gh_vb.draw_lines( vb_id, count, start, render_mode )

Languages

Parameters

vb_id [ID]: vertex buffer identifier
count [INTEGER]: number of vertices that must be drawn
start [INTEGER]: index of the first vertex
render_mode [ENUM]: render mode: 0 (LINE_RENDER_DEFAULT), 1 (LINE_RENDER_STRIP), 2 (LINE_RENDER_LOOP)

Return Values

This function has no return value(s).

Code sample


-- Draws the first 100 vertices as lines.
LINE_RENDER_DEFAULT = 0
LINE_RENDER_STRIP = 1
LINE_RENDER_LOOP = 2

gh_vb.draw_lines(vb_id, 100, 0, LINE_RENDER_STRIP)

draw_points

Description

Draws points from a vertex buffer.

Syntax

gh_vb.draw_points( vb_id, count, start )

Languages

Parameters

vb_id [ID]: vertex buffer identifier
count [INTEGER]: number of points that must be drawn
start [INTEGER]: index of the first point

Return Values

This function has no return value(s).

Code sample


-- Draws the first 100 points.
gh_vb.draw_points(vb_id, 100, 0)

draw_triangles

Description

Draws triangles from a vertex buffer.

Syntax

gh_vb.draw_triangles( vb_id, count, start, triangle_mode )

Languages

Parameters

vb_id [ID]: vertex buffer identifier
count [INTEGER]: number of vertices that must be drawn
start [INTEGER]: index of the first vertex
triangle_mode [ENUM]: triangle mode

Return Values

This function has no return value(s).

Code sample


-- triangle modes:
TRIANGLE = 0
TRIANGLE_STRIP = 1
TRIANGLE_FAN = 9

-- Draws the first 90 vertices as triangles (30 triangles).
gh_vb.draw_triangles(vb_id, 90, 0, TRIANGLE)

kill

Description

Kills a vertex buffer.

Syntax

gh_vb.kill( vb_id )

Languages

Parameters

vb_id [ID]: vertex buffer identifier

Return Values

This function has no return value(s).

Code sample


gh_vb.kill(vb_id)

map

Description

Maps the vertex buffer to CPU memory. The buffer pointer returned by map() is valid until the next call to unmap.

Syntax

buff_ptr, buff_size = gh_vb.map( vb_id, access_mode )

Languages

Parameters

vb_id [ID]: vertex buffer identifier
access_mode [STRING]: XX

Return Values

buff_ptr [POINTER]: pointer to the buffer
buff_size [INTEGER]: size of the buffer in bytes

Code sample


buffer, buffer_size = gh_vb.map(vb_id, "")

set_value_1f

Description

Sets a value in the vertex buffer.

Syntax

gh_vb.set_value_1f( vb_id, buff_offset_bytes, x )

Languages

Parameters

vb_id [ID]: vertex buffer identifier
buff_offset_bytes [INTEGER]: offset in bytes
x [REAL]: value

Return Values

This function has no return value(s).

Code sample


offset = 4
gh_vb.set_value_1f(vb_id, offset, x)

set_value_1ui

Description

Sets a value in the vertex buffer.

Syntax

gh_vb.set_value_1ui( vb_id, buff_offset_bytes, x )

Languages

Parameters

vb_id [ID]: vertex buffer identifier
buff_offset_bytes [INTEGER]: offset in bytes
x [INTEGER]: value

Return Values

This function has no return value(s).

Code sample


offset = 4
gh_vb.set_value_1ui(vb_id, offset, x)

set_value_2f

Description

Sets a value in the vertex buffer.

Syntax

gh_vb.set_value_2f( vb_id, buff_offset_bytes, x, y )

Languages

Parameters

vb_id [ID]: vertex buffer identifier
buff_offset_bytes [INTEGER]: offset in bytes
x, y [REAL]: value

Return Values

This function has no return value(s).

Code sample


offset = 8
gh_vb.set_value_2f(vb_id, offset, x, y)

set_value_3f

Description

Sets a value in the vertex buffer.

Syntax

gh_vb.set_value_3f( vb_id, buff_offset_bytes, x, y, z )

Languages

Parameters

vb_id [ID]: vertex buffer identifier
buff_offset_bytes [INTEGER]: offset in bytes
x, y, z [REAL]: value

Return Values

This function has no return value(s).

Code sample


offset = 12
gh_vb.set_value_3f(vb_id, offset, x, y, z)

set_value_4f

Description

Sets a value in the vertex buffer.

Syntax

gh_vb.set_value_4f( vb_id, buff_offset_bytes, x, y, z, w )

Languages

Parameters

vb_id [ID]: vertex buffer identifier
buff_offset_bytes [INTEGER]: offset in bytes
x, y, z, w [REAL]: value

Return Values

This function has no return value(s).

Code sample


offset = 16
gh_vb.set_value_4f(vb_id, offset, x, y, z, w)

set_value_4x4f

Description

Sets a value in the vertex buffer.

Syntax

gh_vb.set_value_4x4f( vb_id, buff_offset_bytes, m0,m1,m2,m3,m4,m5,m6,m7,m8,m9,m10,m11,m12,m13,m14,m15 )

Languages

Parameters

vb_id [ID]: vertex buffer identifier
buff_offset_bytes [INTEGER]: offset in bytes
m0,m1,m2,m3,m4,m5,m6,m7,m8,m9,m10,m11,m12,m13,m14,m15 [REAL]: the 16 floats that make the 4x4 matrix

Return Values

This function has no return value(s).

Code sample


offset = 64
gh_vb.set_value_4x4f(vb_id, offset, m0,m1,m2,m3,m4,m5,m6,m7,m8,m9,m10,m11,m12,m13,m14,m15)

set_vertex_attrib_data

Description

Specifies the description of a vertex attibute. This description will be used to render the vertex array.

Syntax

gh_vb.set_vertex_attrib_data( vb_id, vertex_attrib_index, attrib_location, type, dim, stride, offset )

Languages

Parameters

vb_id [ID]: vertex buffer identifier
vertex_attrib_index [INTEGER]: XX
attrib_location [INTEGER]: XX
type [INTEGER]: XX
dim [INTEGER]: XX
stride [INTEGER]: XX
offset [INTEGER]: XX

Return Values

This function has no return value(s).

Code sample


gh_vb.set_vertex_attrib_data(vb_id, vertex_attrib_index, attrib_location, type, dim, stride, offset)

unbind

Description

Unbinds a vertex buffer.

Syntax

gh_vb.unbind( vb_id )

Languages

Parameters

vb_id [ID]: vertex buffer identifier

Return Values

This function has no return value(s).

Code sample


gh_vb.unbind(vb_id)

unmap

Description

Unmaps the vertex buffer.

Syntax

gh_vb.unmap( vb_id )

Languages

Parameters

vb_id [ID]: vertex buffer identifier

Return Values

This function has no return value(s).

Code sample


gh_vb.unmap(vb_id)

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