private static void Slide8Render(bool drawOriginal = false, bool drawSamples = false, bool drawFiltered = false)
{
if (frequencyText == null) frequencyText = new Text(Text.FontSize._24pt, "0Hz @ 1000Hz", Slides.Common.TextColor);
float f = t * 0.05f;
if (f * 5000 > Math.PI * 1000) t = 0;
frequencyText.String = string.Format("{0:0.0}Hz @ 1000Hz", f / Math.PI * 5000);
float[] sine = new float[441];
for (int i = 0; i < sine.Length; i++)
sine[i] = 0.5f * (float)Math.Sin((i - 441 / 2) * f);
Slides.Common.DrawPlotter(Utilities.FastMatrix4(new Vector3(72, 720 - 227 - 410, 0), new Vector3(441, 410, 1)));
if (drawOriginal) Slides.Common.DrawPlotLeft(sine, Slides.Common.TitleColor);
float[] samples = new float[441];
for (int i = 0; i < sine.Length; i++)
{
samples[i] = sine[(int)(i / 10) * 10];
}
FilterTools.BiQuad lpf = new FilterTools.BiQuad(2205, 0.707, 44100, 0, FilterTools.BiQuad.Type.LPF);
lpf.Child = (FilterTools.BiQuad)lpf.Clone();
float[] filter = new float[441];
lpf.Load(samples[0]);
for (int i = 0; i < filter.Length; i++) filter[i] = (float)lpf.GetOutput(samples[i]);
if (drawSamples) Slides.Common.DrawPlotLeft(samples, new Vector3(1, 0, 0));
if (drawFiltered) Slides.Common.DrawPlotLeft(filter, new Vector3(0, 1, 0));
if (drawSamples || drawFiltered)
{
frequencyText.ModelMatrix = Matrix4.CreateTranslation(new Vector3(70, 500, 0));
frequencyText.Draw();
}
}
private static void FourierTransformExample(float transformation, bool drawSquare = false, bool drawAbs = false)
{
StopAudioDevice();
if (transformation >= 9.99f) transformation = 9.99f;
transformation /= 10;
float t2 = (transformation > 0.5 ? 1 - transformation : transformation);
float t3 = CubicEaseInOut(t2 * 2, 0, 0.2f, 1);
float t4 = CubicEaseInOut(transformation, 0, 1, 1);
// calculate a cool camera transformation
Matrix4 rotateY = Quaternion.Slerp(Quaternion.Identity, Quaternion.FromRotationMatrix(Matrix4.CreateRotationY((float)Math.PI / 2)), t4).Matrix4;
Matrix4 rotateX = Quaternion.Slerp(Quaternion.Identity, Quaternion.FromRotationMatrix(Matrix4.CreateRotationX((float)Math.PI / -2)), t3).Matrix4 * Matrix4.CreateTranslation(new Vector3(0, t3 * 120, 0));
Matrix4 viewMatrix = rotateY * Matrix4.CreateTranslation(new Vector3(t4 * 100, 0, 0)) * rotateX;
// draw the plotter frame
Gl.Disable(EnableCap.DepthTest);
if (transformation == 0) Slides.Common.DrawPlotter(Utilities.FastMatrix4(new Vector3(72, 720 - 227 - 410, 0), new Vector3(441, 410, 1)));
else if (transformation >= 0.95)
{
Slides.Common.DrawXPlotter(Utilities.FastMatrix4(new Vector3(72, 720 - 227 - 410, 0), new Vector3(441, 410, 1)));
if (drawAbs && fourierText == null)
{
fourierText = new Text(Text.FontSize._24pt, "f 3f 5f 7f 9f 11f ....", Slides.Common.SubtitleColor);
fourierText.ModelMatrix = Matrix4.CreateTranslation(new Vector3(125, 265, 0));
}
if (drawAbs) fourierText.Draw();
}
else Slides.Common.DrawBox(Utilities.FastMatrix4(new Vector3(72, 720 - 227 - 410, 0), new Vector3(441, 410, 1)), Slides.Common.SubtitleColor);
// enable stencil testing to ensure that the plots are clipped to inside the plotter
Slides.Common.EnableStencil(Utilities.FastMatrix4(new Vector3(72, 720 - 227 - 410, 0), new Vector3(441, 410, 1)));
Gl.StencilFunc(StencilFunction.Equal, 1, 0xFFFF);
// create the square wave
if (drawSquare)
{
float[] squareWave = new float[441];
for (int i = 0; i < squareWave.Length; i++) squareWave[i] = ((i % 100) < 50) ? 0.5f : -0.5f;
Slides.Common.Draw3DPlotLeft(squareWave, 0, Slides.Common.TitleColor, viewMatrix);
}
float[] fourier = new float[441];
for (int i = 49; i >= 0; i--)
{
float[] sine = new float[441];
for (int j = 0; j < 441; j++)
{
sine[j] = 0.63662f * (float)Math.Sin(Math.PI * 2 / 100 * j * (1 + i * 2)) / (1 + i * 2);
if (drawAbs) sine[j] = Math.Abs(sine[j]);
fourier[j] += sine[j];
}
if (i < 13)
Slides.Common.Draw3DPlotLeft(sine, (i + 1) * 30, new Vector3(0.2 + i * 0.06f, 0.2 + i * 0.06f, 1), viewMatrix);
}
if (drawSquare) Slides.Common.Draw3DPlotLeft(fourier, 0, new Vector3(1, 0, 0), viewMatrix);
Gl.Disable(EnableCap.StencilTest);
Gl.Enable(EnableCap.DepthTest);
}