gecko-dev/gfx/thebes/gfx3DMatrix.h

/* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 4 -*-
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#ifndef GFX_3DMATRIX_H
#define GFX_3DMATRIX_H

#include <gfxTypes.h>
#include <gfxPoint3D.h>
#include <gfxPointH3D.h>
#include <gfxQuad.h>

struct gfxMatrix;

/**
 * This class represents a 3D transformation. The matrix is laid
 * out as follows:
 *
 * _11 _12 _13 _14
 * _21 _22 _23 _24
 * _31 _32 _33 _34
 * _41 _42 _43 _44
 *
 * This matrix is treated as row-major. Assuming we consider our vectors row
 * vectors, this matrix type will be identical in memory to the OpenGL and D3D
 * matrices. OpenGL matrices are column-major, however OpenGL also treats
 * vectors as column vectors, the double transposition makes everything work
 * out nicely.
 */
class gfx3DMatrix
{
public:
  /**
   * Create matrix.
   */
  gfx3DMatrix(void);

  /**
   * Matrix multiplication.
   */
  gfx3DMatrix operator*(const gfx3DMatrix &aMatrix) const;
  gfx3DMatrix& operator*=(const gfx3DMatrix &aMatrix);

  gfxPointH3D& operator[](int aIndex)
  {
      NS_ABORT_IF_FALSE(aIndex >= 0 && aIndex <= 3, "Invalid matrix array index");
      return *reinterpret_cast<gfxPointH3D*>((&_11)+4*aIndex);
  }
  const gfxPointH3D& operator[](int aIndex) const
  {
      NS_ABORT_IF_FALSE(aIndex >= 0 && aIndex <= 3, "Invalid matrix array index");
      return *reinterpret_cast<const gfxPointH3D*>((&_11)+4*aIndex);
  }

  /**
   * Return true if this matrix and |aMatrix| are the same matrix.
   */
  bool operator==(const gfx3DMatrix& aMatrix) const;
  bool operator!=(const gfx3DMatrix& aMatrix) const;

  bool FuzzyEqual(const gfx3DMatrix& aMatrix) const;
  
  /**
   * Divide all values in the matrix by a scalar value
   */
  gfx3DMatrix& operator/=(gfxFloat scalar);

  /**
   * Create a 3D matrix from a gfxMatrix 2D affine transformation.
   *
   * \param aMatrix gfxMatrix 2D affine transformation.
   */
  static gfx3DMatrix From2D(const gfxMatrix &aMatrix);

  /**
   * Returns true if the matrix is isomorphic to a 2D affine transformation
   * (i.e. as obtained by From2D). If it is, optionally returns the 2D
   * matrix in aMatrix.
   */
  bool Is2D(gfxMatrix* aMatrix) const;
  bool Is2D() const;

  /**
   * Returns true if the matrix can be reduced to a 2D affine transformation
   * (i.e. as obtained by From2D). If it is, optionally returns the 2D
   * matrix in aMatrix. This should only be used on matrices required for
   * rendering, not for intermediate calculations. It is assumed that the 2D
   * matrix will only be used for transforming objects on to the z=0 plane,
   * therefore any z-component perspective is ignored. This means that if
   * aMatrix is applied to objects with z != 0, the results may be incorrect.
   *
   * Since drawing is to a 2d plane, any 3d transform without perspective
   * can be reduced by dropping the z row and column.
   */
  bool CanDraw2D(gfxMatrix* aMatrix = nullptr) const;

  /**
   * Converts the matrix to one that doesn't modify the z coordinate of points,
   * but leaves the rest of the transformation unchanged.
   */
  gfx3DMatrix& ProjectTo2D();

  /**
   * Returns true if the matrix is the identity matrix. The most important
   * property we require is that gfx3DMatrix().IsIdentity() returns true.
   */
  bool IsIdentity() const;

  /**
   * Pre-multiplication transformation functions:
   *
   * These functions construct a temporary matrix containing
   * a single transformation and pre-multiply it onto the current
   * matrix.
   */

  /**
   * Add a translation by aPoint to the matrix.
   *
   * This creates this temporary matrix:
   * |  1        0        0         0 |
   * |  0        1        0         0 |
   * |  0        0        1         0 |
   * |  aPoint.x aPoint.y aPoint.z  1 |
   */
  void Translate(const gfxPoint3D& aPoint);

  /** 
   * Skew the matrix.
   *
   * This creates this temporary matrix:
   * | 1           tan(aYSkew) 0 0 |
   * | tan(aXSkew) 1           0 0 |
   * | 0           0           1 0 |
   * | 0           0           0 1 |
   */
  void SkewXY(double aXSkew, double aYSkew);
  
  void SkewXY(double aSkew);
  void SkewXZ(double aSkew);
  void SkewYZ(double aSkew);

  /**
   * Scale the matrix
   *
   * This creates this temporary matrix:
   * | aX 0  0  0 |
   * | 0  aY 0  0 |
   * | 0  0  aZ 0 |
   * | 0  0  0  1 |
   */
  void Scale(float aX, float aY, float aZ);

  /**
   * Return the currently set scaling factors.
   */
  float GetXScale() const { return _11; }
  float GetYScale() const { return _22; }
  float GetZScale() const { return _33; }

  /**
   * Rotate around the X axis..
   *
   * This creates this temporary matrix:
   * | 1 0            0           0 |
   * | 0 cos(aTheta)  sin(aTheta) 0 |
   * | 0 -sin(aTheta) cos(aTheta) 0 |
   * | 0 0            0           1 |
   */
  void RotateX(double aTheta);
  
  /**
   * Rotate around the Y axis..
   *
   * This creates this temporary matrix:
   * | cos(aTheta) 0 -sin(aTheta) 0 |
   * | 0           1 0            0 |
   * | sin(aTheta) 0 cos(aTheta)  0 |
   * | 0           0 0            1 |
   */
  void RotateY(double aTheta);
  
  /**
   * Rotate around the Z axis..
   *
   * This creates this temporary matrix:
   * | cos(aTheta)  sin(aTheta)  0 0 |
   * | -sin(aTheta) cos(aTheta)  0 0 |
   * | 0            0            1 0 |
   * | 0            0            0 1 |
   */
  void RotateZ(double aTheta);

  /**
   * Apply perspective to the matrix.
   *
   * This creates this temporary matrix:
   * | 1 0 0 0         |
   * | 0 1 0 0         |
   * | 0 0 1 -1/aDepth |
   * | 0 0 0 1         |
   */
  void Perspective(float aDepth);

  /**
   * Pre multiply an existing matrix onto the current
   * matrix
   */
  void PreMultiply(const gfx3DMatrix& aOther);
  void PreMultiply(const gfxMatrix& aOther);

  /**
   * Post-multiplication transformation functions:
   *
   * These functions construct a temporary matrix containing
   * a single transformation and post-multiply it onto the current
   * matrix.
   */

  /**
   * Add a translation by aPoint after the matrix.
   * This is functionally equivalent to:
   * matrix * gfx3DMatrix::Translation(aPoint)
   */
  void TranslatePost(const gfxPoint3D& aPoint);

  void ScalePost(float aX, float aY, float aZ);

  /**
   * Transforms a point according to this matrix.
   */
  gfxPoint Transform(const gfxPoint& point) const;

  /**
   * Transforms a rectangle according to this matrix
   */
  gfxRect TransformBounds(const gfxRect& rect) const;


  gfxQuad TransformRect(const gfxRect& aRect) const;

  /** 
   * Transforms a 3D vector according to this matrix.
   */
  gfxPoint3D Transform3D(const gfxPoint3D& point) const;
  gfxPointH3D Transform4D(const gfxPointH3D& aPoint) const;
  gfxPointH3D TransposeTransform4D(const gfxPointH3D& aPoint) const;

  gfxPoint ProjectPoint(const gfxPoint& aPoint) const;
  gfxRect ProjectRectBounds(const gfxRect& aRect) const;

  /**
   * Transforms a point by the inverse of this matrix. In the case of perspective transforms, some screen
   * points have no equivalent in the untransformed plane (if they exist past the vanishing point). To
   * avoid this, we need to specify the bounds of the untransformed plane to restrict the search area.
   *
   * @param aPoint Point to untransform.
   * @param aChildBounds Bounds of the untransformed plane.
   * @param aOut Untransformed point.
   * @return Returns true if a point was found within a ChildBounds, false otherwise.
   */
  bool UntransformPoint(const gfxPoint& aPoint, const gfxRect& aChildBounds, gfxPoint* aOut) const;


  /**
   * Same as UntransformPoint, but untransforms a rect and returns the bounding rect of the result.
   * Returns an empty rect if the result doesn't intersect aChildBounds.
   */
  gfxRect UntransformBounds(const gfxRect& aRect, const gfxRect& aChildBounds) const;


  /**
   * Inverts this matrix, if possible. Otherwise, the matrix is left
   * unchanged.
   */
  gfx3DMatrix Inverse() const;

  gfx3DMatrix& Invert()
  {
      *this = Inverse();
      return *this;
  }

  gfx3DMatrix& Normalize();

  gfxPointH3D TransposedVector(int aIndex) const
  {
      NS_ABORT_IF_FALSE(aIndex >= 0 && aIndex <= 3, "Invalid matrix array index");
      return gfxPointH3D(*((&_11)+aIndex), *((&_21)+aIndex), *((&_31)+aIndex), *((&_41)+aIndex));
  }

  void SetTransposedVector(int aIndex, gfxPointH3D &aVector)
  {
      NS_ABORT_IF_FALSE(aIndex >= 0 && aIndex <= 3, "Invalid matrix array index");
      *((&_11)+aIndex) = aVector.x;
      *((&_21)+aIndex) = aVector.y;
      *((&_31)+aIndex) = aVector.z;
      *((&_41)+aIndex) = aVector.w;
  }

  gfx3DMatrix& Transpose();
  gfx3DMatrix Transposed() const;

  /**
   * Returns a unit vector that is perpendicular to the plane formed
   * by transform the screen plane (z=0) by this matrix.
   */
  gfxPoint3D GetNormalVector() const;

  /**
   * Returns true if a plane transformed by this matrix will
   * have it's back face visible.
   */
  bool IsBackfaceVisible() const;

  /**
   * Check if matrix is singular (no inverse exists).
   */
  bool IsSingular() const;

  /**
   * Create a translation matrix.
   *
   * \param aX Translation on X-axis.
   * \param aY Translation on Y-axis.
   * \param aZ Translation on Z-axis.
   */
  static gfx3DMatrix Translation(float aX, float aY, float aZ);
  static gfx3DMatrix Translation(const gfxPoint3D& aPoint);

  /**
   * Create a scale matrix. Scales uniformly along all axes.
   *
   * \param aScale Scale factor
   */
  static gfx3DMatrix ScalingMatrix(float aFactor);

  /**
   * Create a scale matrix.
   */
  static gfx3DMatrix ScalingMatrix(float aX, float aY, float aZ);

  gfxFloat Determinant() const;

  void NudgeToIntegers(void);
  void NudgeToIntegersFixedEpsilon();

private:

  gfxFloat Determinant3x3() const;
  gfx3DMatrix Inverse3x3() const;

  gfx3DMatrix Multiply2D(const gfx3DMatrix &aMatrix) const;

public:

  /** Matrix elements */
  float _11, _12, _13, _14;
  float _21, _22, _23, _24;
  float _31, _32, _33, _34;
  float _41, _42, _43, _44;
};

#endif /* GFX_3DMATRIX_H */