1
0
forked from 0ad/0ad
0ad/source/simulation2/helpers/Render.h
2012-04-22 04:04:02 +00:00

197 lines
8.4 KiB
C++

/* Copyright (C) 2012 Wildfire Games.
* This file is part of 0 A.D.
*
* 0 A.D. is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 2 of the License, or
* (at your option) any later version.
*
* 0 A.D. 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with 0 A.D. If not, see <http://www.gnu.org/licenses/>.
*/
#ifndef INCLUDED_HELPER_RENDER
#define INCLUDED_HELPER_RENDER
/**
* @file
* Helper functions related to rendering
*/
#include "maths/Vector2D.h"
class CSimContext;
class CVector2D;
class CVector3D;
class CMatrix3D;
class CBoundingBoxAligned;
class CBoundingBoxOriented;
struct SOverlayLine;
struct SDashedLine
{
/// Packed array of consecutive dashes' points. Use m_StartIndices to navigate it.
std::vector<CVector2D> m_Points;
/**
* Start indices in m_Points of each dash. Dash n starts at point m_StartIndices[n] and ends at the point with index
* m_StartIndices[n+1] - 1, or at the end of the m_Points vector. Use the GetEndIndex(n) convenience method to abstract away the
* difference and get the (exclusive) end index of dash n.
*/
std::vector<size_t> m_StartIndices;
/// Returns the (exclusive) end point index (i.e. index within m_Points) of dash n.
size_t GetEndIndex(size_t i)
{
// for the last dash, there is no next starting index, so we need to use the end index of the m_Points array instead
return (i < m_StartIndices.size() - 1 ? m_StartIndices[i+1] : m_Points.size());
}
};
namespace SimRender
{
/**
* Constructs overlay line from given points, conforming to terrain.
*
* @param[in] xz List of x,z coordinate pairs representing the line.
* @param[in,out] overlay Updated overlay line now conforming to terrain.
* @param[in] floating If true, the line conforms to water as well.
* @param[in] heightOffset Height above terrain to offset the line.
*/
void ConstructLineOnGround(const CSimContext& context, const std::vector<float>& xz,
SOverlayLine& overlay,
bool floating, float heightOffset = 0.25f);
/**
* Constructs overlay line as a circle with given center and radius, conforming to terrain.
*
* @param[in] x,z Coordinates of center of circle.
* @param[in] radius Radius of circle to construct.
* @param[in,out] overlay Updated overlay line representing this circle.
* @param[in] floating If true, the circle conforms to water as well.
* @param[in] heightOffset Height above terrain to offset the circle.
* @param heightOffset The vertical offset to apply to points, to raise the line off the terrain a bit.
*/
void ConstructCircleOnGround(const CSimContext& context, float x, float z, float radius,
SOverlayLine& overlay,
bool floating, float heightOffset = 0.25f);
/**
* Constructs overlay line as rectangle with given center and dimensions, conforming to terrain.
*
* @param[in] x,z Coordinates of center of rectangle.
* @param[in] w,h Width/height dimensions of the rectangle.
* @param[in] a Clockwise angle to orient the rectangle.
* @param[in,out] overlay Updated overlay line representing this rectangle.
* @param[in] floating If true, the rectangle conforms to water as well.
* @param[in] heightOffset Height above terrain to offset the rectangle.
*/
void ConstructSquareOnGround(const CSimContext& context, float x, float z, float w, float h, float a,
SOverlayLine& overlay,
bool floating, float heightOffset = 0.25f);
/**
* Constructs a solid outline of an arbitrarily-aligned bounding @p box.
*
* @param[in] box
* @param[in,out] overlayLine Updated overlay line representing the oriented box.
*/
void ConstructBoxOutline(const CBoundingBoxOriented& box, SOverlayLine& overlayLine);
/**
* Constructs a solid outline of an axis-aligned bounding @p box.
*
* @param[in] bound
* @param[in,out] overlayLine Updated overlay line representing the AABB.
*/
void ConstructBoxOutline(const CBoundingBoxAligned& box, SOverlayLine& overlayLine);
/**
* Constructs a simple gimbal outline with the given radius and center.
*
* @param[in] center
* @param[in] radius
* @param[in,out] out Updated overlay line representing the gimbal.
* @param[in] numSteps The amount of steps to trace a circle's complete outline. Must be a (strictly) positive multiple of four.
* For small radii, you can get away with small values; setting this to 4 will create a diamond shape.
*/
void ConstructGimbal(const CVector3D& center, float radius, SOverlayLine& out, size_t numSteps = 16);
/**
* Constructs 3D axis marker overlay lines for the given coordinate system.
* The XYZ axes are colored RGB, respectively.
*
* @param[in] coordSystem Specifies the coordinate system.
* @param[out] outX,outY,outZ Constructed overlay lines for each axes.
*/
void ConstructAxesMarker(const CMatrix3D& coordSystem, SOverlayLine& outX, SOverlayLine& outY, SOverlayLine& outZ);
/**
* Updates the given points so each point is averaged with its neighbours, resulting in
* a somewhat smoother curve, assuming the points are roughly equally spaced.
*
* @param[in,out] points List of points to smooth.
* @param[in] closed if true, then the points are treated as a closed path (the last is connected
* to the first).
*/
void SmoothPointsAverage(std::vector<CVector2D>& points, bool closed);
/**
* Updates the given points to include intermediate points interpolating between the original
* control points, using a rounded nonuniform spline.
*
* @param[in,out] points List of points to interpolate.
* @param[in] closed if true, then the points are treated as a closed path (the last is connected
* to the first).
* @param[in] offset The points are shifted by this distance in a direction 90 degrees clockwise from
* the direction of the curve.
* @param[in] segmentSamples Amount of intermediate points to sample between every two control points.
*/
void InterpolatePointsRNS(std::vector<CVector2D>& points, bool closed, float offset, int segmentSamples = 4);
/**
* Creates a dashed line from the given line, dash length, and blank space between.
*
* @param[in] linePoints List of points specifying the input line.
* @param[out] dashedLineOut The dashed line returned as a list of smaller lines
* @param[in] dashLength Length of a single dash. Must be strictly positive.
* @param[in] blankLength Length of a single blank between dashes. Must be strictly positive.
*/
void ConstructDashedLine(const std::vector<CVector2D>& linePoints, SDashedLine& dashedLineOut,
const float dashLength, const float blankLength);
/**
* Computes angular step parameters @p out_stepAngle and @p out_numSteps, given a @p maxChordLength on a circle of radius @p radius.
* The resulting values satisfy @p out_numSteps * @p out_stepAngle = 2*PI.
*
* This function is used to find the angular step parameters when drawing a circle outline approximated by several connected chords;
* it returns the step angle and number of steps such that the length of each resulting chord is less than or equal to @p maxChordLength.
* By stating that each chord cannot be longer than a particular length, a certain level of visual smoothness of the resulting circle
* outline can be guaranteed independently of the radius of the outline.
*
* @param radius Radius of the circle. Must be strictly positive.
* @param maxChordLength Desired maximum length of individual chords. Must be strictly positive.
*/
void AngularStepFromChordLen(const float maxChordLength, const float radius, float& out_stepAngle, unsigned& out_numSteps);
/**
* Subdivides a list of @p points into segments of maximum length @p maxSegmentLength that are of equal size between every two
* control points. The resulting subdivided list of points is written back to @p points.
*
* @param points The list of intermediate points to subdivide.
* @param maxSegmentLength The maximum length of a single segment after subdivision. Must be strictly positive.
* @param closed Should the provided list of points be treated as a closed shape? If true, the resulting list of points will include
* extra subdivided points between the last and the first point.
*/
void SubdividePoints(std::vector<CVector2D>& points, float maxSegmentLength, bool closed);
} // namespace
#endif // INCLUDED_HELPER_RENDER