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mutter/cogl/cogl-matrix.h
Robert Bragg d74cf9de81 matrix: Adds cogl_matrix_is_identity API 
This adds a function called cogl_matrix_is_identity that can determine
if a given matrix is an identity matrix or not.

Signed-off-by: Neil Roberts <neil@linux.intel.com>
2011-07-04 15:31:50 +01:00

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/*
* Cogl
*
* An object oriented GL/GLES Abstraction/Utility Layer
*
* Copyright (C) 2008,2009 Intel Corporation.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library. If not, see <http://www.gnu.org/licenses/>.
*
*
*
* Authors:
* Robert Bragg <robert@linux.intel.com>
*/
#ifndef __COGL_MATRIX_H
#define __COGL_MATRIX_H
#include <glib.h>
#include "cogl-types.h"
#ifdef COGL_ENABLE_EXPERIMENTAL_API
#include "cogl-quaternion.h"
#endif
G_BEGIN_DECLS
/**
* SECTION:cogl-matrix
* @short_description: Fuctions for initializing and manipulating 4x4 matrices
*
* Matrices are used in Cogl to describe affine model-view transforms, texture
* transforms, and projective transforms. This exposes a utility API that can
* be used for direct manipulation of these matrices.
*/
/**
* CoglMatrix:
*
* A CoglMatrix holds a 4x4 transform matrix. This is a single precision,
* column-major matrix which means it is compatible with what OpenGL expects.
*
* A CoglMatrix can represent transforms such as, rotations, scaling,
* translation, sheering, and linear projections. You can combine these
* transforms by multiplying multiple matrices in the order you want them
* applied.
*
* The transformation of a vertex (x, y, z, w) by a CoglMatrix is given by:
*
* |[
* x_new = xx * x + xy * y + xz * z + xw * w
* y_new = yx * x + yy * y + yz * z + yw * w
* z_new = zx * x + zy * y + zz * z + zw * w
* w_new = wx * x + wy * y + wz * z + ww * w
* ]|
*
* Where w is normally 1
*
* <note>You must consider the members of the CoglMatrix structure read only,
* and all matrix modifications must be done via the cogl_matrix API. This
* allows Cogl to annotate the matrices internally. Violation of this will give
* undefined results. If you need to initialize a matrix with a constant other
* than the identity matrix you can use cogl_matrix_init_from_array().</note>
*/
struct _CoglMatrix
{
/* column 0 */
float xx;
float yx;
float zx;
float wx;
/* column 1 */
float xy;
float yy;
float zy;
float wy;
/* column 2 */
float xz;
float yz;
float zz;
float wz;
/* column 3 */
float xw;
float yw;
float zw;
float ww;
/*< private >*/
/* Note: we may want to extend this later with private flags
* and a cache of the inverse transform matrix. */
float COGL_PRIVATE (inv)[16];
unsigned long COGL_PRIVATE (type);
unsigned long COGL_PRIVATE (flags);
unsigned long COGL_PRIVATE (_padding3);
};
COGL_STRUCT_SIZE_ASSERT (CoglMatrix, 128 + sizeof (unsigned long) * 3);
/**
* cogl_matrix_init_identity:
* @matrix: A 4x4 transformation matrix
*
* Resets matrix to the identity matrix:
*
* |[
* .xx=1; .xy=0; .xz=0; .xw=0;
* .yx=0; .yy=1; .yz=0; .yw=0;
* .zx=0; .zy=0; .zz=1; .zw=0;
* .wx=0; .wy=0; .wz=0; .ww=1;
* ]|
*/
void
cogl_matrix_init_identity (CoglMatrix *matrix);
/**
* cogl_matrix_multiply:
* @result: The address of a 4x4 matrix to store the result in
* @a: A 4x4 transformation matrix
* @b: A 4x4 transformation matrix
*
* Multiplies the two supplied matrices together and stores
* the resulting matrix inside @result.
*
* <note>It is possible to multiply the @a matrix in-place, so
* @result can be equal to @a but can't be equal to @b.</note>
*/
void
cogl_matrix_multiply (CoglMatrix *result,
const CoglMatrix *a,
const CoglMatrix *b);
/**
* cogl_matrix_rotate:
* @matrix: A 4x4 transformation matrix
* @angle: The angle you want to rotate in degrees
* @x: X component of your rotation vector
* @y: Y component of your rotation vector
* @z: Z component of your rotation vector
*
* Multiplies @matrix with a rotation matrix that applies a rotation
* of @angle degrees around the specified 3D vector.
*/
void
cogl_matrix_rotate (CoglMatrix *matrix,
float angle,
float x,
float y,
float z);
/**
* cogl_matrix_translate:
* @matrix: A 4x4 transformation matrix
* @x: The X translation you want to apply
* @y: The Y translation you want to apply
* @z: The Z translation you want to apply
*
* Multiplies @matrix with a transform matrix that translates along
* the X, Y and Z axis.
*/
void
cogl_matrix_translate (CoglMatrix *matrix,
float x,
float y,
float z);
/**
* cogl_matrix_scale:
* @matrix: A 4x4 transformation matrix
* @sx: The X scale factor
* @sy: The Y scale factor
* @sz: The Z scale factor
*
* Multiplies @matrix with a transform matrix that scales along the X,
* Y and Z axis.
*/
void
cogl_matrix_scale (CoglMatrix *matrix,
float sx,
float sy,
float sz);
/**
* cogl_matrix_frustum:
* @matrix: A 4x4 transformation matrix
* @left: coord of left vertical clipping plane
* @right: coord of right vertical clipping plane
* @bottom: coord of bottom horizontal clipping plane
* @top: coord of top horizontal clipping plane
* @z_near: positive distance to near depth clipping plane
* @z_far: positive distance to far depth clipping plane
*
* Multiplies @matrix by the given frustum perspective matrix.
*/
void
cogl_matrix_frustum (CoglMatrix *matrix,
float left,
float right,
float bottom,
float top,
float z_near,
float z_far);
/**
* cogl_matrix_perspective:
* @matrix: A 4x4 transformation matrix
* @fov_y: A field of view angle for the Y axis
* @aspect: The ratio of width to height determining the field of view angle
* for the x axis.
* @z_near: The distance to the near clip plane. Never pass 0 and always pass
* a positive number.
* @z_far: The distance to the far clip plane. (Should always be positive)
*
* Multiplies @matrix by the described perspective matrix
*
* <note>You should be careful not to have to great a @z_far / @z_near ratio
* since that will reduce the effectiveness of depth testing since there wont
* be enough precision to identify the depth of objects near to each
* other.</note>
*/
void
cogl_matrix_perspective (CoglMatrix *matrix,
float fov_y,
float aspect,
float z_near,
float z_far);
/**
* cogl_matrix_ortho:
* @matrix: A 4x4 transformation matrix
* @left: The coordinate for the left clipping plane
* @right: The coordinate for the right clipping plane
* @bottom: The coordinate for the bottom clipping plane
* @top: The coordinate for the top clipping plane
* @z_near: The coordinate for the near clipping plane (may be negative if
* the plane is behind the viewer)
* @z_far: The coordinate for the far clipping plane (may be negative if
* the plane is behind the viewer)
*
* Multiplies @matrix by a parallel projection matrix.
*/
void
cogl_matrix_ortho (CoglMatrix *matrix,
float left,
float right,
float bottom,
float top,
float z_near,
float z_far);
#ifdef COGL_ENABLE_EXPERIMENTAL_API
#define cogl_matrix_view_2d_in_frustum cogl_matrix_view_2d_in_frustum_EXP
#define cogl_matrix_view_2d_in_perspective \
cogl_matrix_view_2d_in_perspective_EXP
/**
* cogl_matrix_view_2d_in_frustum:
* @matrix: A 4x4 transformation matrix
* @left: coord of left vertical clipping plane
* @right: coord of right vertical clipping plane
* @bottom: coord of bottom horizontal clipping plane
* @top: coord of top horizontal clipping plane
* @z_near: The distance to the near clip plane. Never pass 0 and always pass
* a positive number.
* @z_2d: The distance to the 2D plane. (Should always be positive and
* be between @z_near and the z_far value that was passed to
* cogl_matrix_frustum())
* @width_2d: The width of the 2D coordinate system
* @height_2d: The height of the 2D coordinate system
*
* Multiplies @matrix by a view transform that maps the 2D coordinates
* (0,0) top left and (@width_2d,@height_2d) bottom right the full viewport
* size. Geometry at a depth of 0 will now lie on this 2D plane.
*
* Note: this doesn't multiply the matrix by any projection matrix,
* but it assumes you have a perspective projection as defined by
* passing the corresponding arguments to cogl_matrix_frustum().
* Toolkits such as Clutter that mix 2D and 3D drawing can use this to
* create a 2D coordinate system within a 3D perspective projected
* view frustum.
*/
void
cogl_matrix_view_2d_in_frustum (CoglMatrix *matrix,
float left,
float right,
float bottom,
float top,
float z_near,
float z_2d,
float width_2d,
float height_2d);
/**
* cogl_matrix_view_2d_in_perspective:
* @fov_y: A field of view angle for the Y axis
* @aspect: The ratio of width to height determining the field of view angle
* for the x axis.
* @z_near: The distance to the near clip plane. Never pass 0 and always pass
* a positive number.
* @z_2d: The distance to the 2D plane. (Should always be positive and
* be between @z_near and the z_far value that was passed to
* cogl_matrix_frustum())
* @width_2d: The width of the 2D coordinate system
* @height_2d: The height of the 2D coordinate system
*
* Multiplies @matrix by a view transform that maps the 2D coordinates
* (0,0) top left and (@width_2d,@height_2d) bottom right the full viewport
* size. Geometry at a depth of 0 will now lie on this 2D plane.
*
* Note: this doesn't multiply the matrix by any projection matrix,
* but it assumes you have a perspective projection as defined by
* passing the corresponding arguments to cogl_matrix_perspective().
*
* Toolkits such as Clutter that mix 2D and 3D drawing can use this to
* create a 2D coordinate system within a 3D perspective projected
* view frustum.
*/
void
cogl_matrix_view_2d_in_perspective (CoglMatrix *matrix,
float fov_y,
float aspect,
float z_near,
float z_2d,
float width_2d,
float height_2d);
#endif
/**
* cogl_matrix_init_from_array:
* @matrix: A 4x4 transformation matrix
* @array: A linear array of 16 floats (column-major order)
*
* Initializes @matrix with the contents of @array
*/
void
cogl_matrix_init_from_array (CoglMatrix *matrix,
const float *array);
/**
* cogl_matrix_get_array:
* @matrix: A 4x4 transformation matrix
*
* Casts @matrix to a float array which can be directly passed to OpenGL.
*
* Return value: a pointer to the float array
*/
const float *
cogl_matrix_get_array (const CoglMatrix *matrix);
#ifdef COGL_ENABLE_EXPERIMENTAL_API
/**
* cogl_matrix_init_from_quaternion:
* @matrix: A 4x4 transformation matrix
* @quaternion: A #CoglQuaternion
*
* Initializes @matrix from a #CoglQuaternion rotation.
*
* Return value: a pointer to the float array
*/
void
cogl_matrix_init_from_quaternion (CoglMatrix *matrix,
CoglQuaternion *quaternion);
#endif
/**
* cogl_matrix_equal:
* @v1: A 4x4 transformation matrix
* @v2: A 4x4 transformation matrix
*
* Compares two matrices to see if they represent the same
* transformation. Although internally the matrices may have different
* annotations associated with them and may potentially have a cached
* inverse matrix these are not considered in the comparison.
*
* Since: 1.4
*/
gboolean
cogl_matrix_equal (gconstpointer v1, gconstpointer v2);
/**
* cogl_matrix_copy:
* @matrix: A 4x4 transformation matrix you want to copy
*
* Allocates a new #CoglMatrix on the heap and initializes it with
* the same values as @matrix.
*
* Returns: A newly allocated #CoglMatrix which should be freed using
* cogl_matrix_free()
*
* Since: 1.6
*/
CoglMatrix *
cogl_matrix_copy (const CoglMatrix *matrix);
/**
* cogl_matrix_free:
* @matrix: A 4x4 transformation matrix you want to free
*
* Frees a #CoglMatrix that was previously allocated via a call to
* cogl_matrix_copy().
*
* Since: 1.6
*/
void
cogl_matrix_free (CoglMatrix *matrix);
/**
* cogl_matrix_get_inverse:
* @matrix: A 4x4 transformation matrix
* @inverse: (out): The destination for a 4x4 inverse transformation matrix
*
* Gets the inverse transform of a given matrix and uses it to initialize
* a new #CoglMatrix.
*
* <note>Although the first parameter is annotated as const to indicate
* that the transform it represents isn't modified this function may
* technically save a copy of the inverse transform within the given
* #CoglMatrix so that subsequent requests for the inverse transform may
* avoid costly inversion calculations.</note>
*
* Return value: %TRUE if the inverse was successfully calculated or %FALSE
* for degenerate transformations that can't be inverted (in this case the
* @inverse matrix will simply be initialized with the identity matrix)
*
* Since: 1.2
*/
gboolean
cogl_matrix_get_inverse (const CoglMatrix *matrix,
CoglMatrix *inverse);
/* FIXME: to be consistent with cogl_matrix_{transform,project}_points
* this could be renamed to cogl_matrix_project_point for Cogl 2.0...
*/
/**
* cogl_matrix_transform_point:
* @matrix: A 4x4 transformation matrix
* @x: (inout): The X component of your points position
* @y: (inout): The Y component of your points position
* @z: (inout): The Z component of your points position
* @w: (inout): The W component of your points position
*
* Transforms a point whos position is given and returned as four float
* components.
*/
void
cogl_matrix_transform_point (const CoglMatrix *matrix,
float *x,
float *y,
float *z,
float *w);
#ifdef COGL_ENABLE_EXPERIMENTAL_API
#define cogl_matrix_transform_points cogl_matrix_transform_points_EXP
#define cogl_matrix_project_points cogl_matrix_project_points_EXP
/**
* cogl_matrix_transform_points:
* @matrix: A transformation matrix
* @n_components: The number of position components for each input point.
* (either 2 or 3)
* @stride_in: The stride in bytes between input points.
* @points_in: A pointer to the first component of the first input point.
* @stride_out: The stride in bytes between output points.
* @points_out: A pointer to the first component of the first output point.
* @n_points: The number of points to transform.
*
* Transforms an array of input points and writes the result to
* another array of output points. The input points can either have 2
* or 3 components each. The output points always have 3 components.
* The output array can simply point to the input array to do the
* transform in-place.
*
* If you need to transform 4 component points see
* cogl_matrix_project_points().
*
* Here's an example with differing input/output strides:
* |[
* typedef struct {
* float x,y;
* guint8 r,g,b,a;
* float s,t,p;
* } MyInVertex;
* typedef struct {
* guint8 r,g,b,a;
* float x,y,z;
* } MyOutVertex;
* MyInVertex vertices[N_VERTICES];
* MyOutVertex results[N_VERTICES];
* CoglMatrix matrix;
*
* my_load_vertices (vertices);
* my_get_matrix (&matrix);
*
* cogl_matrix_transform_points (&matrix,
* 2,
* sizeof (MyInVertex),
* &vertices[0].x,
* sizeof (MyOutVertex),
* &results[0].x,
* N_VERTICES);
* ]|
*
* Stability: Unstable
*/
void
cogl_matrix_transform_points (const CoglMatrix *matrix,
int n_components,
size_t stride_in,
const void *points_in,
size_t stride_out,
void *points_out,
int n_points);
/**
* cogl_matrix_project_points:
* @matrix: A projection matrix
* @n_components: The number of position components for each input point.
* (either 2, 3 or 4)
* @stride_in: The stride in bytes between input points.
* @points_in: A pointer to the first component of the first input point.
* @stride_out: The stride in bytes between output points.
* @points_out: A pointer to the first component of the first output point.
* @n_points: The number of points to transform.
*
* Projects an array of input points and writes the result to another
* array of output points. The input points can either have 2, 3 or 4
* components each. The output points always have 4 components (known
* as homogenous coordinates). The output array can simply point to
* the input array to do the transform in-place.
*
* Here's an example with differing input/output strides:
* |[
* typedef struct {
* float x,y;
* guint8 r,g,b,a;
* float s,t,p;
* } MyInVertex;
* typedef struct {
* guint8 r,g,b,a;
* float x,y,z;
* } MyOutVertex;
* MyInVertex vertices[N_VERTICES];
* MyOutVertex results[N_VERTICES];
* CoglMatrix matrix;
*
* my_load_vertices (vertices);
* my_get_matrix (&matrix);
*
* cogl_matrix_project_points (&matrix,
* 2,
* sizeof (MyInVertex),
* &vertices[0].x,
* sizeof (MyOutVertex),
* &results[0].x,
* N_VERTICES);
* ]|
*
* Stability: Unstable
*/
void
cogl_matrix_project_points (const CoglMatrix *matrix,
int n_components,
size_t stride_in,
const void *points_in,
size_t stride_out,
void *points_out,
int n_points);
#endif /* COGL_ENABLE_EXPERIMENTAL_API */
/**
* cogl_matrix_is_identity:
* @matrix: A #CoglMatrix
*
* Determines if the given matrix is an identity matrix.
*
* Returns: %TRUE if @matrix is an identity matrix else %FALSE
* Since: 1.8
*/
gboolean
cogl_matrix_is_identity (const CoglMatrix *matrix);
#ifdef _COGL_SUPPORTS_GTYPE_INTEGRATION
#define COGL_GTYPE_TYPE_MATRIX (cogl_gtype_matrix_get_type ())
/**
* cogl_gtype_matrix_get_type:
*
* Returns the GType for the registered "CoglMatrix" boxed type. This
* can be used for example to define GObject properties that accept a
* #CoglMatrix value.
*/
GType
cogl_gtype_matrix_get_type (void);
#endif /* _COGL_SUPPORTS_GTYPE_INTEGRATION */
G_END_DECLS
#endif /* __COGL_MATRIX_H */
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