Question

尝试获取bmp来包装对象（柱面）。我有一个非图像纹理来包装圆筒，但当我试图用图像做同样的事情时，它就出来了用模糊/白色电视屏幕黑白两色？我将发布我已经改变的内容以尝试让bmp工作。希望我能得到一些答案：d

首先，我需要一个24位真彩色256x256图像。我在Paint中创建了这个将其大小调整为256像素乘256像素并保存为24位（.bmp）

第二个是界面部分。因为它有一些类型和const可能会有所帮助把这个想出来（解决;计算出;弄明白。在这里我添加了类型RTGB，和TWrap以及var wapper。也因为24位窗口bmp文件没有alpha，所以使得Const“ColorComps = 3”而不是4 零件。这是界面，因为它可能会有所帮助。但我认为问题在于readbitmap函数。

unit zap1;

interface

uses
  Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,
  Vcl.Controls,opengl,shapes, Vcl.Forms, Vcl.Dialogs, Transfrm, cOpenGL;

type
 TTexe13=packed record
    red,
    green,
    blue: GLubyte;
  end;

  TTexe14=packed record
    red,
    green,
    blue,
    alpha: gLubyte;
  end;
  TForm2 = class(TForm)
    OpenGL1: TOpenGL;
    Transform1: TTransform;
    procedure FormCreate(Sender: TObject);
    procedure FormResize(Sender: TObject);
    procedure FormPaint(Sender: TObject);
    procedure Transform1Paint(Sender: TObject);
    procedure CylinderT(sTex,tTex:glFloat);
  private
    { Private declarations }
    deltax,
    deltaY,
    deltaZ:GLfloat;
    procedure idle(Sender:TObject;var Done:boolean);
  public
    { Public declarations }
    Function ReadBitmap(const FilePath:string;var sWidth,tHeight:glsizei):pointer;
  end;

var
  Form2: TForm2;

const
  Level=0;
  Border=0;
  ColorComps=3;

type
  TRGB=packed record
    r,g,b: byte;
  end;
  TWrap=array[0..0] of TRGB;
var
  Wrapper: pointer;

接下来我添加了ReadBitmap（我认为我的问题就在这里）。该怎么办.. 打开指定文件，获取文件大小并减去标题大小以获取实际位图的大小。然后它读取文件头并检查有效的位图签名。接下来，该函数读取信息标题并提取宽度和高度（以像素为单位），它通过var参数与调用者通信

  finally it allocates the required memory and asigns the bimap into that memory. the function then returns a pointer to the memory containing the raw true-color bitmap. Then at the end i added a pixel-flipping loop. due to openGL uses RGB and windows BGR.



Function TForm2.ReadBitmap(const FilePath:String;var sWidth,tHeight:GLsizei):pointer;
const
  szh=SizeOf(TBitmapFileHeader);
  szi=SizeOf(TBitmapInfoHeader);
var
  bmpfile: file;
  bfh:TBitmapFileHeader;
  bmi:TBitmapInfoHeader;
  t:byte;
  x,
  fpos,
  size: integer;
begin
  assignfile(bmpfile,FilePath);
  reset(bmpfile,1);
  size := FileSize(bmpfile)-szh-szi;
  blockread(bmpfile,bfh,szh);
  if bfh.bfType<>$4D42  then
    raise EinvalidGraphic.Create('Invalid Bitmap');
  blockread(bmpfile,bmi,szi);
  with bmi do
  begin
    sWidth := biWidth;
    tHeight := biHeight;
  end;
  getmem(result,size);
  blockread(bmpfile,result^,size);
  for x  := 0 to sWidth*tHeight-1 do
  with TWrap(result^)[x] do
  begin
    t := r;
    r := b;
    b := t;
  end;
end;

最后，我为oncreate事件添加了一些更新。 var sWidth和tHeight 它应该从读取位图函数获得宽度/高度。和openGL命令包装

 Wrapper := ReadBitmap('SomeImage.bmp',sWidth,tHeight);
  glTexImage2D(GL_TEXTURE_2D,Level,ColorComps,sWidth,tHeight,Border,GL_RGB,GL_UNSIGNED_BYTE,Wrapper);
  freemem(Wrapper);

现在看起来像

procedure TForm2.FormCreate(Sender: TObject);
var
  swidth,
  theight: GLsizei;
begin
  glPixelStorei(GL_UNPACK_ALIGNMENT,1);
  glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_WRAP_S,GL_REPEAT);
  glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_WRAP_T,GL_REPEAT);
  glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MAG_FILTER,GL_NEAREST);
  glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MIN_FILTER,GL_NEAREST);
  Wrapper := ReadBitmap('Fig11-11.bmp',sWidth,tHeight);
  glTexImage2D(GL_TEXTURE_2D,Level,ColorComps,sWidth,tHeight,Border,GL_RGBA,GL_UNSIGNED_BYTE,Wrapper);
  freemem(wrapper);
  glEnable(GL_TEXTURE_2D);
  glTexEnvf(GL_TEXTURE_ENV,GL_TEXTURE_ENV_MODE,GL_DECAL);
  application.OnIdle := idle;
  deltaX := 0.01;
  deltaY := 0.01;
  deltaZ := 0.01;
  cylinderBase;
end;

Answer 1

glTexImage2D(GL_TEXTURE_2D,Level,ColorComps,sWidth,tHeight,Border,GL_RGBA,GL_UNSIGNED_BYTE,Wrapper);

要

glTexImage2D(GL_TEXTURE_2D,Level,ColorComps,sWidth,tHeight,Border,GL_RGB,GL_UNSIGNED_BYTE,Wrapper);

刚从GL_RGB中取出A

添加.bmp作为未正确显示的封面

1 个答案: