easy3d::opengl Namespace Reference

OpenGL-related functionalities for reading pixel/depth data from the framebuffer. More...

Functions
bool	check_gl_error (const std::string &file, const std::string &function, int line, std::ostream &os=std::cerr)
	Checks the last OpenGL error.
bool	check_frame_buffer_error (const std::string &file, const std::string &function, int line, std::ostream &os=std::cerr)
	Checks the last framebuffer error.
bool	gl_error (std::string &msg)
	Checks if there was an OpenGL error. If there was an error, the error message will be stored in "msg".
bool	frame_buffer_error (std::string &msg)
	Checks if there was a framebuffer error. If there was an error, the error message will be stored in "msg".
void	setup_gl_debug_callback ()
	Set up a debug callback for OpenGL.
void	read_color (unsigned char rgba[4], int x, int y)
	Read color value at pixel (x, y) from the current non-multisample framebuffer.
void	read_color_ms (unsigned char rgba[4], int x, int y)
	Read color value at pixel (x, y) from the current multisample framebuffer.
void	read_depth (float &depth, int x, int y)
	Read depth value at pixel (x, y) from the current non-multisample framebuffer.
void	read_depth_ms (float &depth, int x, int y)
	Read depth value at pixel (x, y) from the current multisample framebuffer.
void	read_color (std::vector< unsigned char > &buffer, unsigned int format, bool flip_vertically=true)
	Read color data of the current non-multisample framebuffer into a specified buffer.
void	read_color_ms (std::vector< unsigned char > &buffer, unsigned int format, bool flip_vertically=true)
	Read color data of the current multisample framebuffer into a specified buffer.
void	snapshot_color (const std::string &file_name)
	Snapshot the color render buffer of the current non-multisample framebuffer into an image file. This is very useful for debugging.
void	snapshot_color_ms (const std::string &file_name)
	Snapshot the color render buffer of the current multisample framebuffer into an image file. This is very useful for debugging.
void	read_depth (std::vector< float > &buffer, bool flip_vertically=true)
	Read the depth data of the current non-multisample framebuffer into a specified buffer.
void	read_depth_ms (std::vector< float > &buffer, bool flip_vertically=true)
	Read the depth data of the current multisample framebuffer into a specified buffer.
void	snapshot_depth (const std::string &file_name)
	Snapshot the depth render buffer of the current non-multisample framebuffer into an image file. This is very useful for debugging.
void	snapshot_depth_ms (const std::string &file_name)
	Snapshot the depth render buffer of the current multisample framebuffer into an image file. This is very useful for debugging.

Detailed Description

OpenGL-related functionalities for reading pixel/depth data from the framebuffer.

For multisample-version functions, a normal framebuffer is created for bliting color/depth from the multisample framebuffer object. For high-frequent queries, you'd better create a normal fbo for bliting operations. This way, you can avoid frequently allocating and deallocating GPU memories.

Function Documentation

check_frame_buffer_error()

bool check_frame_buffer_error	(	const std::string &	file,
		const std::string &	function,
		int	line,
		std::ostream &	os = std::cerr )

Checks the last framebuffer error.

Parameters

file	The file name where the error occurred.
function	The function name where the error occurred.
line	The line number where the error occurred.
os	The output stream to write the error message. Default is std::cerr.

Returns

false if an error indeed occurred.

See also

check_gl_error.

check_gl_error()

bool check_gl_error	(	const std::string &	file,
		const std::string &	function,
		int	line,
		std::ostream &	os = std::cerr )

Checks the last OpenGL error.

Parameters

file	The file name where the error occurred.
function	The function name where the error occurred.
line	The line number where the error occurred.
os	The output stream to write the error message. Default is std::cerr.

Returns

false if an error indeed occurred.

See also

check_frame_buffer_error.

frame_buffer_error()

bool frame_buffer_error

(

std::string &

msg

)

Checks if there was a framebuffer error. If there was an error, the error message will be stored in "msg".

Parameters

msg	The error message.

Returns

false if an error occurred.

See also

frame_buffer_error.

gl_error()

bool gl_error

(

std::string &

msg

)

Checks if there was an OpenGL error. If there was an error, the error message will be stored in "msg".

Parameters

msg	The error message.

Returns

false if an error occurred.

See also

frame_buffer_error.

read_color() [1/2]

void read_color	(	std::vector< unsigned char > &	buffer,
		unsigned int	format,
		bool	flip_vertically = true )

Read color data of the current non-multisample framebuffer into a specified buffer.

Parameters

buffer	The buffer to store the color data.
format	The format of the pixel data. Supported formats: GL_RGB, GL_BGR, GL_RGBA, and GL_BGRA.
flip_vertically	Flip the image data vertically if it is true (default value). This is convenient for OpenGL applications where the first pixel in the output array is expected to be the bottom left corner of the image.

See also

read_color_ms.

read_color() [2/2]

void read_color	(	unsigned char	rgba[4],
		int	x,
		int	y )

Read color value at pixel (x, y) from the current non-multisample framebuffer.

Parameters

rgba	The color value.
x	The x-coordinate of the pixel, represented in the OpenGL coordinate system.
y	The y-coordinate of the pixel, represented in the OpenGL coordinate system.

See also

read_color_ms.

read_color_ms() [1/2]

void read_color_ms	(	std::vector< unsigned char > &	buffer,
		unsigned int	format,
		bool	flip_vertically = true )

Read color data of the current multisample framebuffer into a specified buffer.

Parameters

buffer	The buffer to store the color data.
format	The format of the pixel data. Supported formats: GL_RGB, GL_BGR, GL_RGBA, and GL_BGRA.
flip_vertically	Flip the image data vertically if it is true (default value). This is convenient for OpenGL applications where the first pixel in the output array is expected to be the bottom left corner of the image.

See also

read_color.

read_color_ms() [2/2]

void read_color_ms	(	unsigned char	rgba[4],
		int	x,
		int	y )

Read color value at pixel (x, y) from the current multisample framebuffer.

Parameters

rgba	The color value.
x	The x-coordinate of the pixel, represented in the OpenGL coordinate system.
y	The y-coordinate of the pixel, represented in the OpenGL coordinate system.

read_depth() [1/2]

void read_depth	(	float &	depth,
		int	x,
		int	y )

Read depth value at pixel (x, y) from the current non-multisample framebuffer.

Parameters

depth	The depth value.
x	The x-coordinate of the pixel, represented in the OpenGL coordinate system.
y	The y-coordinate of the pixel, represented in the OpenGL coordinate system.

See also

read_depth_ms.

read_depth() [2/2]

void read_depth	(	std::vector< float > &	buffer,
		bool	flip_vertically = true )

Read the depth data of the current non-multisample framebuffer into a specified buffer.

Parameters

buffer	The buffer to store the depth data.
flip_vertically	Flip the image data vertically if it is true (default value). This is convenient for OpenGL applications where the first pixel in the output array is expected to be the bottom left corner of the image.

See also

read_depth_ms.

read_depth_ms() [1/2]

void read_depth_ms	(	float &	depth,
		int	x,
		int	y )

Read depth value at pixel (x, y) from the current multisample framebuffer.

Parameters

depth	The depth value.
x	The x-coordinate of the pixel, represented in the OpenGL coordinate system.
y	The y-coordinate of the pixel, represented in the OpenGL coordinate system.

See also

read_depth.

read_depth_ms() [2/2]

void read_depth_ms	(	std::vector< float > &	buffer,
		bool	flip_vertically = true )

Read the depth data of the current multisample framebuffer into a specified buffer.

Parameters

buffer	The buffer to store the depth data.
flip_vertically	Flip the image data vertically if it is true (default value). This is convenient for OpenGL applications where the first pixel in the output array is expected to be the bottom left corner of the image.

See also

read_depth.

setup_gl_debug_callback()

void setup_gl_debug_callback

(

)

Set up a debug callback for OpenGL.

Note

This has effect only if the working OpenGL version is >= 4.3.

Examples

Tutorial_203_Viewer_wxWidgets/main.cpp, and Tutorial_204_Viewer_Qt/main.cpp.

snapshot_color()

void snapshot_color

(

const std::string &

file_name

)

Snapshot the color render buffer of the current non-multisample framebuffer into an image file. This is very useful for debugging.

Parameters

file_name

The file name of the image file. Supported formats: png, jpg, bmp, tga, and ppm. File format is determined by the extension of the file name.

See also

snapshot_color_ms.

snapshot_color_ms()

void snapshot_color_ms

(

const std::string &

file_name

)

Snapshot the color render buffer of the current multisample framebuffer into an image file. This is very useful for debugging.

Parameters

file_name

The file name of the image file. Supported formats: png, jpg, bmp, tga, and ppm. File format is determined by the extension of the file name.

See also

snapshot_color.

snapshot_depth()

void snapshot_depth

(

const std::string &

file_name

)

Snapshot the depth render buffer of the current non-multisample framebuffer into an image file. This is very useful for debugging.

Parameters

file_name

The file name of the image file. Supported formats: png, jpg, bmp, tga, and ppm. File format is determined by the extension of the file name.

See also

snapshot_depth_ms.

snapshot_depth_ms()

void snapshot_depth_ms

(

const std::string &

file_name

)

Snapshot the depth render buffer of the current multisample framebuffer into an image file. This is very useful for debugging.

Parameters

file_name

The file name of the image file. Supported formats: png, jpg, bmp, tga, and ppm. File format is determined by the extension of the file name.

See also

snapshot_depth.