bgi_camera.h File Reference

Internal GLM-based camera math for the camera viewport system. More...

#include "bgi_types.h"
#include <glm/glm.hpp>
#include <glm/gtc/matrix_transform.hpp>
#include <glm/gtc/type_ptr.hpp>
#include <vector>

Include dependency graph for bgi_camera.h:

Go to the source code of this file.

Namespaces
namespace	bgi

Functions
float	bgi::cameraAspectRatio (const Camera3D &cam, int winW, int winH)
	Returns the aspect ratio (width / height) of the camera's effective viewport.
bool	bgi::cameraClipToScreen (const Camera3D &cam, int winW, int winH, const glm::vec4 &clip, float &screenX, float &screenY)
	Project a 4-D clip-space point (after SH clipping) to a screen pixel.
void	bgi::cameraEffectiveViewport (const Camera3D &cam, int winW, int winH, int &x, int &y, int &w, int &h)
	Returns the effective screen-space viewport rectangle (pixels) for a camera.
glm::mat4	bgi::cameraProjMatrix (const Camera3D &cam, float aspectRatio)
	Builds the projection matrix.
void	bgi::cameraScreenToRay (const Camera3D &cam, int winW, int winH, float screenX, float screenY, float &rayOx, float &rayOy, float &rayOz, float &rayDx, float &rayDy, float &rayDz)
	Unprojects a screen pixel to a world-space ray.
glm::mat4	bgi::cameraViewMatrix (const Camera3D &cam)
	Builds the view matrix from eye / target / up, or from the 2-D pan / zoom / rotation fields when cam.is2D is true.
glm::mat4	bgi::cameraVPMatrix (const Camera3D &cam, float aspectRatio)
	Returns the combined view-projection matrix (proj × view).
glm::vec4	bgi::cameraWorldToClip (const Camera3D &cam, int winW, int winH, float wx, float wy, float wz)
	Transform a world-space point to 4-D clip space via the camera's VP matrix.
bool	bgi::cameraWorldToScreen (const Camera3D &cam, int winW, int winH, float wx, float wy, float wz, float &screenX, float &screenY)
	Projects a world-space point to a screen pixel.
bool	bgi::cameraWorldToScreenForced (const Camera3D &cam, int winW, int winH, float wx, float wy, float wz, float &screenX, float &screenY)
	Like cameraWorldToScreen but skips the NDC frustum boundary test.
bool	bgi::clipLineByPlane (glm::vec4 &A, glm::vec4 &B, const glm::vec4 &plane)
	Clip a LINE SEGMENT in clip space against one half-space in place.
bool	bgi::clipLineZPlanes (glm::vec4 &A, glm::vec4 &B)
	Clip a line segment against near and far Z planes.
void	bgi::clipPolyByPlane (std::vector< glm::vec4 > &poly, const glm::vec4 &plane)
	Sutherland-Hodgman clip step: clip a convex polygon (in 4-D clip space) against one half-space.
void	bgi::clipPolyZPlanes (std::vector< glm::vec4 > &poly)
	Clip a convex polygon in clip space against the near plane (Z+W>0) and far plane (-Z+W>0).
void	bgi::matToFloatArray (const glm::mat4 &m, float *out16)
	Writes a GLM mat4 into a caller-supplied column-major float[16] array.

Detailed Description

Internal GLM-based camera math for the camera viewport system.

All functions operate on Camera3D values stored in BgiState::cameras. The coordinate convention throughout is Z-up, right-handed (AutoCAD / engineering style): the XY plane is the ground plane and +Z points upward.

OpenGL uses a Y-up convention internally; the conversion is handled transparently inside the view-matrix construction for 2-D cameras and is the caller's responsibility for 3-D cameras (set upZ = 1 for the default Z-up orientation).

None of these functions are part of the public C API. Consumers use the wxbgi_cam_* / wxbgi_cam2d_* functions declared in wx_bgi_3d.h.