easy3d::shape Namespace Reference

A collection of functions for rendering basic shapes. More...

Functions
Functions for drawing
void	draw_quad_wire (const Rect &rect, const vec4 &color, int width, int height, float depth)
	Draws a wire quad defined in the screen space.
void	draw_quad_filled (const Rect &rect, const vec4 &color, int width, int height, float depth)
	Draws a solid quad defined in the screen space.
void	draw_quad_filled (const Rect &rect, unsigned int texture, int width, int height, float depth)
	Draws a solid quad defined in the screen space.
void	draw_full_screen_quad (unsigned int texture, float depth)
	Draws a full screen textured quad.
void	draw_depth_texture (const Rect &rect, unsigned int texture, int width, int height, float depth)
	Draws a quad visualizing a depth texture in a region.
void	draw_quad (unsigned int position_attrib, unsigned int texcoord_attrib, int x, int y, int w, int h, int vpw, int vph, float depth)
	Draws a quad defined in the screen space using a bound shader.
void	draw_full_screen_quad (unsigned int position_attrib, unsigned int texcoord_attrib, float depth)
	Draws a full screen quad using the bound shader.
void	draw_polygon_wire (const Polygon2 &polygon, const vec4 &color, int width, int height, float depth)
	Draws a polygon (line loop) in the screen space.
void	draw_polygon_filled (const Polygon2 &polygon, const vec4 &color, int width, int height, float depth)
	Draws a filled polygon in the screen space.
void	draw_sphere_big_circles (LinesDrawable *drawable, const mat4 &mvp, const mat4 &m, bool axes=true)
	Draws the outline (the 3 big circles) of a sphere.
void	draw_box_wire (LinesDrawable *drawable, const mat4 &mvp, const mat4 &m, bool abstracted=false)
	Draws a box.
Functions for creating basic shapes (data preparation)
void	create_grid (int x_steps, int y_steps, std::vector< vec3 > &points, float depth=0.0f, float scale=0.5f)
	Generates data for a grid as a set of line segments.
void	create_box (std::vector< vec3 > &points, std::vector< vec3 > &colors, bool abstracted=false)
	Generates data for a unit box as a set of line segments.
void	create_circle (int slices, std::vector< vec3 > &points, std::vector< unsigned int > &indices)
	Generates data for a unit circle as a set of line segments.
void	create_sphere (const vec3 &center, double radius, int slices, int stacks, const vec3 &color, std::vector< vec3 > &points, std::vector< vec3 > &normals, std::vector< vec3 > &colors)
	Generates data (points, normals, and colors) for a 3D sphere.
void	create_checker_sphere (const vec3 &center, double radius, int slices, int stacks, int checker_size, const vec3 &color1, const vec3 &color2, std::vector< vec3 > &points, std::vector< vec3 > &normals, std::vector< vec3 > &colors)
	Generates data (points, normals, and colors) for a 3D checker sphere.
void	create_cylinder (double radius, int slices, const vec3 &s, const vec3 &t, const vec3 &color, std::vector< vec3 > &points, std::vector< vec3 > &normals, std::vector< vec3 > &colors)
	Prepares data (points, normals, and colors) for a 3D cylinder defined by two 3D points s and t.
void	create_cone (double radius, int slices, const vec3 &s, const vec3 &t, const vec3 &color, std::vector< vec3 > &points, std::vector< vec3 > &normals, std::vector< vec3 > &colors)
	Prepares data (points, normals, and colors) for a 3D cone defined by two 3D points b and t.
void	create_torus (double major_radius, double minor_radius, int major_slices, int minor_slices, std::vector< vec3 > &points, std::vector< vec3 > &normals)
	Prepares data for representing a torus.
void	create_camera (std::vector< vec3 > &points, float width, float fov, float hw_ratio=0.6f)
	Generates data (points) for representing a camera in the 3D world as a set of lines.
void	create_camera (std::vector< vec3 > &points, std::vector< unsigned int > &indices, float width, float fov, float hw_ratio=0.6f)
	Prepares data (points) for representing a camera in the 3D world as a set of triangles.

Detailed Description

A collection of functions for rendering basic shapes.

Function Documentation

create_box()

void create_box	(	std::vector< vec3 > &	points,
		std::vector< vec3 > &	colors,
		bool	abstracted = false )

Generates data for a unit box as a set of line segments.

The box is centered at vec3(0, 0, 0) and is aligned with the main axes.

Parameters

points	The points to be returned.
colors	The colors of the points.
abstracted	true to draw an abstracted version (only part of its corners).

create_camera() [1/2]

void create_camera	(	std::vector< vec3 > &	points,
		float	width,
		float	fov,
		float	hw_ratio = 0.6f )

Generates data (points) for representing a camera in the 3D world as a set of lines.

Parameters

points	The points to be returned.
width	The width of the camera. A good value can be 5% of the scene radius, or 10% of the character height (in walking mode).
fov	The vertical field of view of the camera (in radians).
hw_ratio	The aspect ratio of the base quad defined as height/width (default 0.6).

create_camera() [2/2]

void create_camera	(	std::vector< vec3 > &	points,
		std::vector< unsigned int > &	indices,
		float	width,
		float	fov,
		float	hw_ratio = 0.6f )

Prepares data (points) for representing a camera in the 3D world as a set of triangles.

Parameters

points	The points to be returned.
indices	The vertex indices to be returned.
width	The width of the camera. A good value can be 5% of the scene radius, or 10% of the character height (in walking mode).
fov	The vertical field of view of the camera (in radians).
hw_ratio	The aspect ratio of the base quad defined as height/width (default 0.6).

create_checker_sphere()

void create_checker_sphere	(	const vec3 &	center,
		double	radius,
		int	slices,
		int	stacks,
		int	checker_size,
		const vec3 &	color1,
		const vec3 &	color2,
		std::vector< vec3 > &	points,
		std::vector< vec3 > &	normals,
		std::vector< vec3 > &	colors )

Generates data (points, normals, and colors) for a 3D checker sphere.

Parameters

center	the center of the sphere.
radius	the radius of the sphere.
slices	the number of subdivisions around the z axis (similar to lines of longitude).
stacks	the number of subdivisions along the z axis(similar to lines of latitude).
checker_size	how many tiles each checker will occupy.
color1	one of the two interchanging colors.
color2	the other one of the two interchanging colors.
points	the points to be returned.
normals	the normals to be returned.
colors	the colors to be returned.

create_circle()

void create_circle	(	int	slices,
		std::vector< vec3 > &	points,
		std::vector< unsigned int > &	indices )

Generates data for a unit circle as a set of line segments.

The circle is centered at vec3(0, 0, 0) and lies on the XOY plane.

Parameters

slices	The number of subdivisions.
points	The points to be returned.
indices	The indices of the points.

create_cone()

void create_cone	(	double	radius,
		int	slices,
		const vec3 &	s,
		const vec3 &	t,
		const vec3 &	color,
		std::vector< vec3 > &	points,
		std::vector< vec3 > &	normals,
		std::vector< vec3 > &	colors )

Prepares data (points, normals, and colors) for a 3D cone defined by two 3D points b and t.

Parameters

radius	The radius of the cone.
slices	The number of subdivisions around the z axis (similar to lines of longitude).
s	The base center.
t	The top center.
color	The color of the cone.
points	The points to be returned.
normals	The normals to be returned.
colors	The colors to be returned.

Examples

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

create_cylinder()

void create_cylinder	(	double	radius,
		int	slices,
		const vec3 &	s,
		const vec3 &	t,
		const vec3 &	color,
		std::vector< vec3 > &	points,
		std::vector< vec3 > &	normals,
		std::vector< vec3 > &	colors )

Prepares data (points, normals, and colors) for a 3D cylinder defined by two 3D points s and t.

Parameters

radius	The radius of the cylinder.
slices	The number of subdivisions around the z axis (similar to lines of longitude).
s	The base center.
t	The top center.
color	The color of the cylinder.
points	The points to be returned.
normals	The normals to be returned.
colors	The colors to be returned.

Examples

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

create_grid()

void create_grid	(	int	x_steps,
		int	y_steps,
		std::vector< vec3 > &	points,
		float	depth = 0.0f,
		float	scale = 0.5f )

Generates data for a grid as a set of line segments.

The grid is centered at vec3(0, 0, 0) and lies on the XOY plane.

Parameters

x_steps	The number of subdivisions along X direction.
y_steps	The number of subdivisions along Y direction.
depth	The depth (Z value) of the generated points.
points	The points to be returned.
scale	The scaling factor

create_sphere()

void create_sphere	(	const vec3 &	center,
		double	radius,
		int	slices,
		int	stacks,
		const vec3 &	color,
		std::vector< vec3 > &	points,
		std::vector< vec3 > &	normals,
		std::vector< vec3 > &	colors )

Generates data (points, normals, and colors) for a 3D sphere.

Parameters

center	the center of the sphere.
radius	the radius of the sphere.
slices	the number of subdivisions around the z axis (similar to lines of longitude).
stacks	the number of subdivisions along the z axis(similar to lines of latitude).
color	the color of the sphere.
points	the points to be returned.
normals	the normals to be returned.
colors	the colors to be returned.

Examples

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

create_torus()

void create_torus	(	double	major_radius,
		double	minor_radius,
		int	major_slices,
		int	minor_slices,
		std::vector< vec3 > &	points,
		std::vector< vec3 > &	normals )

Prepares data for representing a torus.

Parameters

major_radius	The radius of major circle.
minor_radius	The radius of minor circle.
major_slices	The number of subdivisions along the major circle (suggested value 50).
minor_slices	The number of subdivisions along the minor circle (suggested value 20).
points	Returns the points.
normals	Returns the normals.

draw_box_wire()

void draw_box_wire	(	LinesDrawable *	drawable,
		const mat4 &	mvp,
		const mat4 &	m,
		bool	abstracted = false )

Draws a box.

Parameters

drawable	The drawable.
mvp	The model view projection matrix.
m	The transformation matrix defining the box's location, sizes, and orientation.
abstracted	true to draw an abstracted version (only part of its corners).

draw_depth_texture()

void draw_depth_texture	(	const Rect &	rect,
		unsigned int	texture,
		int	width,
		int	height,
		float	depth )

Draws a quad visualizing a depth texture in a region.

This is function is similar to draw_quad_filled(... int texture...). The only difference is that a depth texture is rendered as a gray scale image. For depth textures from off-screen rendering (usually from an FBO), the depth values are stored in the R component of the texture.

Parameters

rect	The quad.
texture	The texture.
width	The width of the viewer.
height	The height of the viewer.
depth	The depth at which the quad will be drawn. The depth value is the Normalized Device Coordinates within the range [-1.0, 1.0], corresponding to the near and far clipping planes, respectively.

draw_full_screen_quad() [1/2]

void draw_full_screen_quad	(	unsigned int	position_attrib,
		unsigned int	texcoord_attrib,
		float	depth )

Draws a full screen quad using the bound shader.

It binds the vertex position and UVs arrays to the given attribute array indices and draws the quad.

Parameters

position_attrib	The vertex attribute array index that represents position in the current shader.
texcoord_attrib	The vertex attribute array index that represents 2D UVs in the current shader.
depth	The depth at which the quad will be drawn. The depth value is the Normalized Device Coordinates within the range [-1.0, 1.0], corresponding to the near and far clipping planes, respectively.

draw_full_screen_quad() [2/2]

void draw_full_screen_quad	(	unsigned int	texture,
		float	depth )

Draws a full screen textured quad.

Parameters

texture	The texture.
depth	The depth at which the quad will be drawn. The depth value is the Normalized Device Coordinates within the range [-1.0, 1.0], corresponding to the near and far clipping planes, respectively.

draw_polygon_filled()

void draw_polygon_filled	(	const Polygon2 &	polygon,
		const vec4 &	color,
		int	width,
		int	height,
		float	depth )

Draws a filled polygon in the screen space.

Parameters

polygon	The polygon.
color	The color.
width	The width of the viewer.
height	The height of the viewer.
depth	The depth at which the polygon will be drawn. The depth value is the Normalized Device Coordinates within the range [-1.0, 1.0], corresponding to the near and far clipping planes, respectively.

To make the polygon transparent, do the following

glEnable(GL_BLEND);
glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
draw_polygon_filled(...);
glDisable(GL_BLEND);

draw_polygon_wire()

void draw_polygon_wire	(	const Polygon2 &	polygon,
		const vec4 &	color,
		int	width,
		int	height,
		float	depth )

Draws a polygon (line loop) in the screen space.

Parameters

polygon	The polygon.
color	The color.
width	The width of the viewer.
height	The height of the viewer.
depth	The depth at which the polygon will be drawn. The depth value is the Normalized Device Coordinates within the range [-1.0, 1.0], corresponding to the near and far clipping planes, respectively.

draw_quad()

void draw_quad	(	unsigned int	position_attrib,
		unsigned int	texcoord_attrib,
		int	x,
		int	y,
		int	w,
		int	h,
		int	vpw,
		int	vph,
		float	depth )

Draws a quad defined in the screen space using a bound shader.

It binds the vertex position and UVs arrays to the given attribute array indices and draws the quad.

Parameters

position_attrib	The vertex attribute array index that represents position in the current shader.
texcoord_attrib	The vertex attribute array index that represents 2D UVs in the current shader.
x	The x coordinate of the min corner of the quad.
y	The y coordinate of the min corner of the quad.
w	The width of the quad.
h	The height of the quad.
vpw	The width of the viewport (of the viewer).
vph	The height of the viewport (of the viewer).
depth	The depth at which the quad will be drawn. The depth value is the Normalized Device Coordinates within the range [-1.0, 1.0], corresponding to the near and far clipping planes, respectively.

draw_quad_filled() [1/2]

void draw_quad_filled	(	const Rect &	rect,
		const vec4 &	color,
		int	width,
		int	height,
		float	depth )

Draws a solid quad defined in the screen space.

Parameters

rect	The quad.
color	The color.
width	The width of the viewer.
height	The height of the viewer.
depth	The depth at which the quad will be drawn. The depth value is the Normalized Device Coordinates within the range [-1.0, 1.0], corresponding to the near and far clipping planes, respectively.

draw_quad_filled() [2/2]

void draw_quad_filled	(	const Rect &	rect,
		unsigned int	texture,
		int	width,
		int	height,
		float	depth )

Draws a solid quad defined in the screen space.

Parameters

rect	The quad.
texture	The texture.
width	The width of the viewer.
height	The height of the viewer.
depth	The depth at which the quad will be drawn. The depth value is the Normalized Device Coordinates within the range [-1.0, 1.0], corresponding to the near and far clipping planes, respectively.

draw_quad_wire()

void draw_quad_wire	(	const Rect &	rect,
		const vec4 &	color,
		int	width,
		int	height,
		float	depth )

Draws a wire quad defined in the screen space.

Parameters

rect	The quad.
color	The color.
width	The width of the viewer.
height	The height of the viewer.
depth	The depth at which the quad will be drawn. The depth value is the Normalized Device Coordinates within the range [-1.0, 1.0], corresponding to the near and far clipping planes, respectively.

draw_sphere_big_circles()

void draw_sphere_big_circles	(	LinesDrawable *	drawable,
		const mat4 &	mvp,
		const mat4 &	m,
		bool	axes = true )

Draws the outline (the 3 big circles) of a sphere.

Parameters

drawable	The drawable.
mvp	The model view projection matrix.
m	The transformation matrix defining the sphere's location, radius, and orientation.
axes	true will also draw the three main axes.