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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, write to the
* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
* Boston, MA 02111-1307, USA.
*
* Authors:
* Robert Bragg <robert@linux.intel.com>
*/
#ifndef __COGL_MATRIX_H
#define __COGL_MATRIX_H
#include <glib.h>
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:
* <programlisting>
* 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
* </programlisting>
* 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().
*/
typedef 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 _padding0[16];
gulong _padding1;
gulong _padding2;
gulong _padding3;
} CoglMatrix;
/**
* cogl_matrix_init_identity:
* @matrix: A 4x4 transformation matrix
*
* Resets matrix to the identity matrix:
* <programlisting>
* .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;
* </programlisting>
*/
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
*
* This function multiples the two supplied matricies together and stores
* the result in @result
*/
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
*
* This function multiples your 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
*
* This function multiples your 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
*
* This function multiples your 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
* @near: positive distance to near depth clipping plane
* @far: positive distance to far depth clipping plane
*
* Multiplies the 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_transform_point:
* @matrix: A 4x4 transformation matrix
* @x: The X component of your points position [in:out]
* @y: The Y component of your points position [in:out]
* @z: The Z component of your points position [in:out]
* @w: The W component of your points position [in:out]
*
* This 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);
/**
* cogl_matrix_init_from_array:
* @matrix: A 4x4 transformation matrix
* @array: A linear array of 16 floats (column-major order)
*
* This initialises @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
*
* This casts a CoglMatrix to a float array which can be directly passed to
* OpenGL.
*/
const float *cogl_matrix_get_array (const CoglMatrix *matrix);
G_END_DECLS
#endif /* __COGL_MATRIX_H */
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