63047e1907
Adds a few more gtk-doc notes to cogl-matrix.h, and adds a new section to cogl-sections.txt
147 lines
3.6 KiB
C
147 lines
3.6 KiB
C
#ifndef __COGL_MATRIX_H
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#define __COGL_MATRIX_H
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#include <glib.h>
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G_BEGIN_DECLS
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/**
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* SECTION:cogl-matrix
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* @short_description: Fuctions for initializing and manipulating 4x4
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* matrices.
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*
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* Matrices are used in Cogl to describe affine model-view transforms and
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* texture transforms, and projective transforms. This exposes a utility API
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* that can be used for direct manipulation of these matrices.
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*/
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/**
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* CoglMatrix:
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*
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* A CoglMatrix holds a 4x4 transform matrix. This is a single precision,
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* column-major matrix which means it is compatible with what OpenGL expects.
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*
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* A CoglMatix can represent transforms such as, rotations, scaling,
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* translation, sheering, and linear projections. You can combine these
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* transforms by multiplying multiple matrices in the order you want them
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* applied.
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*
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* The transformation of a vertex (x, y, z, w) by a CoglMatrix is given by:
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* <programlisting>
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* x_new = xx * x + xy * y + xz * z + xw * w
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* y_new = yx * x + yy * y + yz * z + yw * w
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* z_new = zx * x + zy * y + zz * z + zw * w
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* w_new = wx * x + wy * y + wz * z + ww * w
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* </programlisting>
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* Where w is normally 1
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*/
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typedef struct _CoglMatrix {
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/* column 0 */
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float xx;
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float yx;
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float zx;
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float wx;
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/* column 1 */
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float xy;
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float yy;
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float zy;
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float wy;
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/* column 2 */
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float xz;
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float yz;
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float zz;
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float wz;
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/* column 3 */
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float xw;
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float yw;
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float zw;
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float ww;
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/*< private >*/
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/* Note: we may want to extend this later with private flags
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* and a cache of the inverse transform matrix. */
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} CoglMatrix;
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/**
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* cogl_matrix_init_identity:
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* @matrix: A 4x4 transformation matrix
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*
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* Resets matrix to the identity matrix:
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* <programlisting>
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* .xx=1; .xy=0; .xz=0; .xw=0;
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* .yx=0; .yy=1; .yz=0; .yw=0;
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* .zx=0; .zy=0; .zz=1; .zw=0;
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* .wx=0; .wy=0; .wz=0; .ww=1;
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* </programlisting>
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*/
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void cogl_matrix_init_identity (CoglMatrix *matrix);
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/**
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* cogl_matrix_multiply:
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* @result: The address of a 4x4 matrix to store the result in
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* @a: A 4x4 transformation matrix
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* @b: A 4x4 transformation matrix
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*
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* This function multiples the two supplied matricies together and stores
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* the result in #result
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*/
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void cogl_matrix_multiply (CoglMatrix *result,
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const CoglMatrix *a,
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const CoglMatrix *b);
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/**
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* cogl_matrix_rotate:
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* @matrix: A 4x4 transformation matrix
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* @angle: The angle you want to rotate in degrees
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* @x: X component of your rotation vector
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* @y: Y component of your rotation vector
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* @z: Z component of your rotation vector
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*
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* This function multiples your matrix with a rotation matrix that applies
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* a rotation of #angle degrees around the specified 3D vector.
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*/
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void cogl_matrix_rotate (CoglMatrix *matrix,
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float angle,
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float x,
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float y,
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float z);
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/* cogl_matrix_translate:
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* @matrix: A 4x4 transformation matrix
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* @x: The X translation you want to apply
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* @y: The Y translation you want to apply
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* @z: The Z translation you want to apply
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*
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* This function multiples your matrix with a transform matrix that translates
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* along the X, Y and Z axis.
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*/
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void cogl_matrix_translate (CoglMatrix *matrix,
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float x,
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float y,
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float z);
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/**
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* cogl_matrix_scale:
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* @matrix: A 4x4 transformation matrix
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* @sx: The X scale factor
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* @sy: The Y scale factor
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* @sz: The Z scale factor
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*
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* This function multiples your matrix with a transform matrix that scales
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* along the X, Y and Z axis.
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*/
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void cogl_matrix_scale (CoglMatrix *matrix,
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float sx,
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float sy,
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float sz);
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G_END_DECLS
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#endif /* __COGL_MATRIX_H */
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