smoothstep_example.cpp

// Description: Smooth-step function example
// DocumentationOf: smoothstep.h

#include "pastel_example.h"

#include "pastel/math/smoothstep.h"

#include "pastel/gfx/savepcx.h"
#include "pastel/gfx/drawing.h"
#include "pastel/gfx/color_tools.h"

#include "pastel/sys/random.h"
#include "pastel/sys/views.h"

using namespace Pastel;

namespace
{

    void testSmoothStep()
    {
        const integer Width = 500;
        const integer Height = 500;

        Array<Color, 2> image(Vector2i(Width, Height));

        const integer Points = 100;

        drawSegment(Segment2(Vector2(0, 0), Vector2(Width, Height)), Color(1, 1, 1), arrayView(image));

        for (integer i = 0;i < Points;++i)
        {
            const real tFrom = (real)i / Points;
            const real tTo = (real)(i + 1) / Points;

            const Vector2 from(Width * tFrom, Height * cubicSmoothStep(tFrom));
            const Vector2 to(Width * tTo, Height * cubicSmoothStep(tTo));

            drawSegment(
                Segment2(from, to), Color(0, 1, 0), arrayView(image));
        }

        for (integer i = 0;i < Points;++i)
        {
            const real tFrom = (real)i / Points;
            const real tTo = (real)(i + 1) / Points;

            const Vector2 from(Width * tFrom, Height * quarticSmoothStep(tFrom * tFrom));
            const Vector2 to(Width * tTo, Height * quarticSmoothStep(tTo * tTo));

            drawSegment(
                Segment2(from, to), Color(1, 0, 0), arrayView(image));
        }

        for (integer i = 0;i < Points;++i)
        {
            const real tFrom = (real)i / Points;
            const real tTo = (real)(i + 1) / Points;

            const Vector2 from(Width * tFrom, Height * quinticSmoothStep(tFrom));
            const Vector2 to(Width * tTo, Height * quinticSmoothStep(tTo));

            drawSegment(
                Segment2(from, to), Color(0, 0, 1), arrayView(image));
        }

        savePcx(image, "smoothstep.pcx");
    }

    void test()
    {
        testSmoothStep();
    }

    void addTest()
    {
        testRunner().add("SmoothStep", test);
    }

    CallFunction run(addTest);

}