PhongShading: How to HALF fill a cylinder with color?
lazarus / 39-Graphics

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Awesome Programmer · 2025-07-22 19:49

I've been playing with PhongShading lately and I actually like and
enjoy testing PhongShading. However, in my program I want to not only
draw a cylinder but also mimic cylinder half full with color using
FILL or any procedures or functions. For the life of me, I can't seem
to find any example anywhere on the internet. Can some please show me
how? thanks.

Oops! I forgot to include my code.

Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i unit
Unit1; {$mode objfpc}{$H+} interface uses  Classes, SysUtils,
FileUtil, Forms, Controls, Graphics, Dialogs,
BGRABitmap,BGRABitmapTypes,  BGRAGradients, fpWeb, fpHttp; type   {
TForm1 }   TForm1 = class(TForm)    procedure FormCreate(Sender:
TObject);    procedure FormDestroy(Sender: TObject);    procedure
FormPaint(Sender: TObject);  private    { private declarations } 
public    { public declarations }  end; var  Form1: TForm1; 
Phong:TPhongShading; implementation {$R *.lfm} { TForm1 } procedure
TForm1.FormCreate(Sender: TObject);begin  Phong :=
TPhongShading.Create;  Phong.LightPositionZ:=150; 
Phong.SpecularIndex:=20;  Phong.AmbientFactor:=0.3; 
Phong.LightSourceIntensity:=250; 
Phong.LightSourceDistanceTerm:=200;end; procedure
TForm1.FormDestroy(Sender: TObject);begin  phong.Free;end; procedure
TForm1.FormPaint(Sender: TObject);var  image:TBGRABitmap;begin  image
:= TBGRABitmap.Create(300,300,ColorToBGRA(ColorToRGB(clbtnface)));  
Phong.DrawVerticalCylinder(image,
rect(20,20,120,400),50,BGRA(255,0,0));  phong.LightPosition :=
Point(100,100);   image.Draw(Canvas,0,0,True);  image.free;end; end.

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TBMan · 2025-07-22 23:28

I'd draw a half sized filled cylinder in an unfilled large cylinder if
I really had no other choice.