igl::opengl Namespace Reference

Namespaces
namespace	glfw
namespace	stb

Classes
struct	gliGenericImage
class	MeshGL
	Coverts mesh data inside a igl::ViewerData class in an OpenGL compatible format The class includes a shader and the opengl calls to plot the data. More...
struct	TgaFooter
struct	TgaHeader
class	ViewerCore
	Basic class of the 3D mesh viewer. More...
class	ViewerData
	Object being drawn (i.e., mesh and its accessories) by the ViewerCore. More...

Functions
bool	render_to_tga (const std::string tga_file, const int width, const int height, const bool alpha)
	alpha whether to include alpha channel
bool	texture_from_tga (const std::string tga_file, GLuint &id)
	Read an image from a .tga file and use it as a texture.
gliGenericImage *	gliReadTGA (FILE *fp, char *name, int hflip, int vflip)
int	gli_verbose (int new_verbose)
int	gliVerbose (int newVerbose)
void	writeTGA (gliGenericImage *image, FILE *fp)
template<typename Scalar , int RowsAtCompileTime, int ColsAtCompileTime>
GLint	bind_vertex_attrib_array (const GLuint program_shader, const std::string &name, GLuint bufferID, const Eigen::Matrix< Scalar, RowsAtCompileTime, ColsAtCompileTime, Eigen::RowMajor > &M, const bool refresh)
	Bind a per-vertex array attribute and refresh its contents from an Eigen matrix.
void	create_index_vbo (const Eigen::MatrixXi &F, GLuint &F_vbo_id)
	Create a VBO (Vertex Buffer Object) for a list of indices: GL_ELEMENT_ARRAY_BUFFER_ARB for the triangle indices (F)
void	create_mesh_vbo (const Eigen::MatrixXd &V, const Eigen::MatrixXi &F, GLuint &V_vbo_id, GLuint &F_vbo_id)
	Create a VBO (Vertex Buffer Object) for a mesh.
void	create_mesh_vbo (const Eigen::MatrixXd &V, const Eigen::MatrixXi &F, const Eigen::MatrixXd &N, GLuint &V_vbo_id, GLuint &F_vbo_id, GLuint &N_vbo_id)
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.
bool	create_shader_program (const std::string &geom_source, const std::string &vert_source, const std::string &frag_source, const std::map< std::string, GLuint > &attrib, GLuint &id)
	Create a shader program with a vertex and fragments shader loading from source strings and vertex attributes assigned from a map before linking the shaders to the program, making it ready to use with glUseProgram(id)
bool	create_shader_program (const std::string &vert_source, const std::string &frag_source, const std::map< std::string, GLuint > &attrib, GLuint &id)
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.
GLuint	create_shader_program (const std::string &geom_source, const std::string &vert_source, const std::string &frag_source, const std::map< std::string, GLuint > &attrib)
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.
GLuint	create_shader_program (const std::string &vert_source, const std::string &frag_source, const std::map< std::string, GLuint > &attrib)
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.
template<typename T >
void	create_vector_vbo (const Eigen::Matrix< T, Eigen::Dynamic, Eigen::Dynamic > &V, GLuint &V_vbo_id)
	Create a VBO (Vertex Buffer Object) for a list of vectors: GL_ARRAY_BUFFER for the vectors (V)
bool	destroy_shader_program (const GLuint id)
	Properly destroy a shader program.
int	gl_type_size (const GLenum type)
	Return the number of bytes for a given OpenGL type.
void	init_render_to_texture (const size_t width, const size_t height, const bool depth_texture, GLuint &tex_id, GLuint &fbo_id, GLuint &d_id)
	Create a frame buffer that renders color to a RGBA texture a depth to a "render buffer".
void	init_render_to_texture (const size_t width, const size_t height, GLuint &tex_id, GLuint &fbo_id, GLuint &dfbo_id)
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.
GLuint	load_shader (const std::string &src, const GLenum type)
	Creates and compiles a shader from a given string.
void	print_program_info_log (const GLuint obj)
	Print the information log for a program object.
void	print_shader_info_log (const GLuint obj)
	Print the info log for a shader object.
template<typename T >
void	read_pixels (const GLuint width, const GLuint height, Eigen::Matrix< T, Eigen::Dynamic, Eigen::Dynamic > &R, Eigen::Matrix< T, Eigen::Dynamic, Eigen::Dynamic > &G, Eigen::Matrix< T, Eigen::Dynamic, Eigen::Dynamic > &B, Eigen::Matrix< T, Eigen::Dynamic, Eigen::Dynamic > &A, Eigen::Matrix< T, Eigen::Dynamic, Eigen::Dynamic > &D)
	Read full viewport into color, alpha and depth arrays suitable for igl::png::writePNG.
GLenum	report_gl_error (const std::string id)
	Print last OpenGL error to stderr prefixed by specified id string.
GLenum	report_gl_error ()
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.
std::string	uniform_type_to_string (const GLenum type)
	Convert a GL uniform variable type (say, returned from glGetActiveUniform) and output a string naming that type.
void	decompress_verasansmono_atlas (unsigned char *_fontatlas)
	Decompress the vera sans mono font atlas.
template<typename DerivedV , typename DerivedF >
void	vertex_array (const Eigen::PlainObjectBase< DerivedV > &V, const Eigen::PlainObjectBase< DerivedF > &F, GLuint &va_id, GLuint &ab_id, GLuint &eab_id)
	Create a GL_VERTEX_ARRAY for a given mesh (V,F)

Function Documentation

render_to_tga()

bool igl::opengl::render_to_tga	(	const std::string	tga_file,
		const int	width,
		const int	height,
		const bool	alpha
	)

alpha whether to include alpha channel

texture_from_tga()

bool igl::opengl::texture_from_tga	(	const std::string	tga_file,
		GLuint &	id
	)

Read an image from a .tga file and use it as a texture.

Parameters

[in]	tga_file	path to .tga file
[out]	id	of generated openGL texture

Returns

true on success, false on failure

gliReadTGA()

gliGenericImage * igl::opengl::gliReadTGA ( FILE *  fp, char *  name, int  hflip, int  vflip  )

extern

gli_verbose()

int igl::opengl::gli_verbose

(

int

new_verbose

)

gliVerbose()

int igl::opengl::gliVerbose ( int  newVerbose )

extern

writeTGA()

void igl::opengl::writeTGA	(	gliGenericImage *	image,
		FILE *	fp
	)

bind_vertex_attrib_array()

template<typename Scalar , int RowsAtCompileTime, int ColsAtCompileTime>

GLint igl::opengl::bind_vertex_attrib_array	(	const GLuint	program_shader,
		const std::string &	name,
		GLuint	bufferID,
		const Eigen::Matrix< Scalar, RowsAtCompileTime, ColsAtCompileTime, Eigen::RowMajor > &	M,
		const bool	refresh
	)

Bind a per-vertex array attribute and refresh its contents from an Eigen matrix.

Parameters

[in]	program_shader	id of shader program
[in]	name	name of attribute in vertex shader
[in]	bufferID	id of buffer to bind to
[in]	M	#V by dim matrix of per-vertex data
[in]	refresh	whether to actually call glBufferData or just bind the buffer

Returns

id of named attribute in shader

create_index_vbo()

void igl::opengl::create_index_vbo	(	const Eigen::MatrixXi &	F,
		GLuint &	F_vbo_id
	)

Create a VBO (Vertex Buffer Object) for a list of indices: GL_ELEMENT_ARRAY_BUFFER_ARB for the triangle indices (F)

Parameters

[in]	F	#F by 3 eigen Matrix of face (triangle) indices
[out]	F_vbo_id	buffer id for face indices

create_mesh_vbo() [1/2]

void igl::opengl::create_mesh_vbo	(	const Eigen::MatrixXd &	V,
		const Eigen::MatrixXi &	F,
		GLuint &	V_vbo_id,
		GLuint &	F_vbo_id
	)

Create a VBO (Vertex Buffer Object) for a mesh.

Actually two VBOs: one GL_ARRAY_BUFFER for the vertex positions (V) and one GL_ELEMENT_ARRAY_BUFFER for the triangle indices (F)

Parameters

[in]	V	#V by 3 eigen Matrix of mesh vertex 3D positions
[in]	F	#F by 3 eigen Matrix of face (triangle) indices
[out]	V_vbo_id	buffer id for vertex positions
[out]	F_vbo_id	buffer id for face indices

Note

when using glDrawElements VBOs for V and F using MatrixXd and MatrixXi will have types GL_DOUBLE and GL_UNSIGNED_INT respectively

create_mesh_vbo() [2/2]

void igl::opengl::create_mesh_vbo	(	const Eigen::MatrixXd &	V,
		const Eigen::MatrixXi &	F,
		const Eigen::MatrixXd &	N,
		GLuint &	V_vbo_id,
		GLuint &	F_vbo_id,
		GLuint &	N_vbo_id
	)

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

Parameters

[in]	N	#V by 3 eigen Matrix of mesh vertex 3D normals
[out]	N_vbo_id	buffer id for vertex positions

create_shader_program() [1/4]

bool igl::opengl::create_shader_program	(	const std::string &	geom_source,
		const std::string &	vert_source,
		const std::string &	frag_source,
		const std::map< std::string, GLuint > &	attrib,
		GLuint &	id
	)

Create a shader program with a vertex and fragments shader loading from source strings and vertex attributes assigned from a map before linking the shaders to the program, making it ready to use with glUseProgram(id)

Parameters

[in]	geom_source	string containing source code of geometry shader (can be "" to mean use default pass-through)
[in]	vert_source	string containing source code of vertex shader
[in]	frag_source	string containing source code of fragment shader
[in]	attrib	map containing table of vertex attribute strings add their correspondingly ids (generated previously using glBindAttribLocation)
[out]	id	index id of created shader, set to 0 on error

Returns

true on success, false on error

Note

Caller is responsible for making sure that current value of id is not leaking a shader (since it will be overwritten)

See also

destroy_shader_program

create_shader_program() [2/4]

bool igl::opengl::create_shader_program	(	const std::string &	vert_source,
		const std::string &	frag_source,
		const std::map< std::string, GLuint > &	attrib,
		GLuint &	id
	)

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

create_shader_program() [3/4]

GLuint igl::opengl::create_shader_program	(	const std::string &	geom_source,
		const std::string &	vert_source,
		const std::string &	frag_source,
		const std::map< std::string, GLuint > &	attrib
	)

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

Returns

index id of created shader, set to 0 on error

create_shader_program() [4/4]

GLuint igl::opengl::create_shader_program	(	const std::string &	vert_source,
		const std::string &	frag_source,
		const std::map< std::string, GLuint > &	attrib
	)

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

Returns

index id of created shader, set to 0 on error

create_vector_vbo()

template<typename T >

void igl::opengl::create_vector_vbo	(	const Eigen::Matrix< T, Eigen::Dynamic, Eigen::Dynamic > &	V,
		GLuint &	V_vbo_id
	)

Create a VBO (Vertex Buffer Object) for a list of vectors: GL_ARRAY_BUFFER for the vectors (V)

Template Parameters

T	should be a eigen matrix primitive type like int or double

Parameters

[in]	V	m by n eigen Matrix of type T values
[out]	V_vbo_id	buffer id for vectors

destroy_shader_program()

bool igl::opengl::destroy_shader_program

(

const GLuint

id

)

Properly destroy a shader program.

Detach and delete each of its shaders and delete it

Parameters

[in]

id

index id of created shader, set to 0 on error

Returns

true on success, false on error

Note

caller is responsible for making sure he doesn't foolishly continue to use id as if it still contains a program

See also

create_shader_program

gl_type_size()

int igl::opengl::gl_type_size

(

const GLenum

type

)

Return the number of bytes for a given OpenGL type.

Parameters

[in]

type

enum value of opengl type

Returns

size in bytes of type

init_render_to_texture() [1/2]

void igl::opengl::init_render_to_texture	(	const size_t	width,
		const size_t	height,
		const bool	depth_texture,
		GLuint &	tex_id,
		GLuint &	fbo_id,
		GLuint &	d_id
	)

Create a frame buffer that renders color to a RGBA texture a depth to a "render buffer".

After calling this, you can use with something like:

glBindFramebuffer(GL_FRAMEBUFFER, fbo_id);
if(!depth_texture)
{
  glBindRenderbuffer(GL_RENDERBUFFER, d_id);
}
//
// draw scene ...
//
// clean up
glBindFramebuffer(GL_FRAMEBUFFER,0);
if(!depth_texture)
{
  glBindRenderbuffer(GL_RENDERBUFFER, 0);
}
// Later ...
glActiveTexture(GL_TEXTURE0+0);
glBindTexture(GL_TEXTURE_2D,tex_id);
if(depth_texture)
{
  glActiveTexture(GL_TEXTURE0+1);
  glBindTexture(GL_TEXTURE_2D,d_id);
}
// draw textures

Parameters

[in]	width	image width
[in]	height	image height
[in]	depth_texture	whether to create a texture for depth or to create a render buffer for depth
[out]	tex_id	id of the texture
[out]	fbo_id	id of the frame buffer object
[out]	d_id	id of the depth texture or frame buffer object

init_render_to_texture() [2/2]

void igl::opengl::init_render_to_texture	(	const size_t	width,
		const size_t	height,
		GLuint &	tex_id,
		GLuint &	fbo_id,
		GLuint &	dfbo_id
	)

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

Wrapper with depth_texture = false for legacy reasons

load_shader()

GLuint igl::opengl::load_shader	(	const std::string &	src,
		const GLenum	type
	)

Creates and compiles a shader from a given string.

Parameters

[in]	src	string containing GLSL shader code
[in]	type	GLSL type of shader, one of: GL_VERTEX_SHADER GL_FRAGMENT_SHADER GL_GEOMETRY_SHADER

Returns

index id of the newly created shader, 0 on error

Will immediately return 0 if src is empty.

print_program_info_log()

void igl::opengl::print_program_info_log

(

const GLuint

obj

)

Print the information log for a program object.

Parameters

[in]

obj

OpenGL index of program to print info log about

print_shader_info_log()

void igl::opengl::print_shader_info_log

(

const GLuint

obj

)

Print the info log for a shader object.

Parameters

[in]

obj

OpenGL index of shader to print info log about

read_pixels()

template<typename T >

void igl::opengl::read_pixels	(	const GLuint	width,
		const GLuint	height,
		Eigen::Matrix< T, Eigen::Dynamic, Eigen::Dynamic > &	R,
		Eigen::Matrix< T, Eigen::Dynamic, Eigen::Dynamic > &	G,
		Eigen::Matrix< T, Eigen::Dynamic, Eigen::Dynamic > &	B,
		Eigen::Matrix< T, Eigen::Dynamic, Eigen::Dynamic > &	A,
		Eigen::Matrix< T, Eigen::Dynamic, Eigen::Dynamic > &	D
	)

Read full viewport into color, alpha and depth arrays suitable for igl::png::writePNG.

Parameters

[in]	width	width of viewport
[in]	height	height of viewport
[out]	R	width by height list of red values
[out]	G	width by height list of green values
[out]	B	width by height list of blue values
[out]	A	width by height list of alpha values
[out]	D	width by height list of depth values

report_gl_error() [1/2]

GLenum igl::opengl::report_gl_error

(

const std::string

id

)

Print last OpenGL error to stderr prefixed by specified id string.

Parameters

[in]

id

string to appear before any error msgs

Returns

result of glGetError()

report_gl_error() [2/2]

GLenum igl::opengl::report_gl_error

(

)

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

uniform_type_to_string()

std::string igl::opengl::uniform_type_to_string

(

const GLenum

type

)

Convert a GL uniform variable type (say, returned from glGetActiveUniform) and output a string naming that type.

Parameters

[in]

type

enum for given type

Returns

string name of that type

decompress_verasansmono_atlas()

void igl::opengl::decompress_verasansmono_atlas

(

unsigned char *

_fontatlas

)

Decompress the vera sans mono font atlas.

vertex_array()

template<typename DerivedV , typename DerivedF >

void igl::opengl::vertex_array	(	const Eigen::PlainObjectBase< DerivedV > &	V,
		const Eigen::PlainObjectBase< DerivedF > &	F,
		GLuint &	va_id,
		GLuint &	ab_id,
		GLuint &	eab_id
	)

Create a GL_VERTEX_ARRAY for a given mesh (V,F)

Parameters

[in]	V	#V by dim list of mesh vertex positions
[in]	F	#F by 3 list of mesh triangle indices into V
[out]	va_id	id of vertex array
[out]	ab_id	id of array buffer (vertex buffer object)
[out]	eab_id	id of element array buffer (element/face buffer object)

Note

Unlike most libigl functions, the input Eigen matrices must be Eigen::PlainObjectBase because we want to directly access it's underlying storage. It cannot be Eigen::MatrixBase (see http://stackoverflow.com/questions/25094948/)