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/*
This file is part of the MinGfx Project.
Copyright (c) 2017,2018 Regents of the University of Minnesota.
All Rights Reserved.
Original Author(s) of this File:
Dan Keefe, 2018, University of Minnesota
Author(s) of Significant Updates/Modifications to the File:
...
*/
#ifndef SRC_GFXMATH_H_
#define SRC_GFXMATH_H_
#include "point2.h"
#include "point3.h"
#include "vector3.h"
#include "matrix4.h"
namespace mingfx {
/** This class holds a variety of static math functions that are useful to have
defined with creating graphics programs.
*/
class GfxMath {
public:
/// Returns a if x is less than a and b if x is greater than b.
static float Clamp(float x, float a, float b);
static float ToRadians(float degrees);
static float ToDegrees(float radians);
static Vector3 ToRadians(Vector3 degrees);
static Vector3 ToDegrees(Vector3 radians);
static float Lerp(float a, float b, float alpha);
static int iLerp(int a, int b, float alpha);
/// Converts a 2D point on the filmplane represented in Normalized Device
/// Coorindates, which means (-1,1) for the top left corner of the screen and
/// (1,-1) for the bottom right corner, to a 3D point that lies on the camera's
/// near plane. Useful for converting mouse coordinates into a 3D point.
/// Remember that this uses NORMALIZED device coordinates for the screenPt,
/// not pixels. GraphicsApp and most other graphics engines report mouse move
/// events in pixels, so you need to convert these to normalized device coordinates
/// first. If you are using GraphicsApp, you can do this with:
/// Point2 normPos = graphicsApp->pixels_to_normalized_coordinates(mousePos);
static Point3 ScreenToNearPlane(const Matrix4 &viewMatrix, const Matrix4 &projMatrix, const Point2 &normalizedScreenPt);
/// Similar to filmplane2D_to_nearplane3D() but here rather than using the
/// nearplane, you specify the depth of the plane to use as a distance away
/// from the camera's focal point.
static Point3 ScreenToDepthPlane(const Matrix4 &viewMatrix, const Matrix4 &projMatrix, const Point2 &normalizedScreenPt, float planeDepth);
/// Converts a 2D point on the filmplane represented in Normalized Device
/// Coorindates, which means (-1,1) for the top left corner of the screen and
/// (1,-1) for the bottom right corner, to a 3D point in the world. The depth
/// buffer value under the pixel must be supplied. If you are using GraphicsApp,
/// you can use the mouse pos in pixels to get the required arguments like this:
/// Point2 normPos = graphicsApp->pixels_to_normalized_coordinates(mousePos);
/// float normZ = graphicsApp->z_value_at_pixel(mousePos);
static Point3 ScreenToWorld(const Matrix4 &viewMatrix, const Matrix4 &projMatrix, const Point2 &normalizedScreenPt, float normalizedZ);
static const float PI;
static const float TWO_PI;
static const float HALF_PI;
};
} // end namespace
#endif
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