gla_texture.inc

{
GLA中的纹理操作单元
}
{$IFDEF GLA_INTERFACE}
{$IFDEF GLA_DEBUG}
{$INFO Compiling gla_texture::interface}
{$ENDIF}
function glaLoadTexture(fnm:string):GLUint;
{$ENDIF}

{$IFDEF GLA_IMPLEMENTATION}
{$IFDEF GLA_DEBUG}
{$INFO Compiling gla_texture::implementation}
{$ENDIF}
function glaLoadTexture(fnm:string):GLUInt;
var
	Reader:TFPCustomImageReader;
	img:TFPMemoryImage;
	s:string;
	t,i,j,p:longint;
	texture:GLUInt;
	PTexture:^Byte;
begin
	s:=fnm;
	p:=pos('.',fnm);
	while p<>0 do begin
		delete(fnm,1,p);
		p:=pos('.',fnm);
	end;
	fnm:=LowerCase(fnm);
	if fnm='bmp' then Reader:=TFPReaderBMP.Create
	else if fnm='png' then Reader:=TFPReaderPNG.Create
	else if (fnm='jpg')or(fnm='jpeg') then Reader:=TFPReaderJPEG.Create
	else if fnm='gif' then Reader:=TFPReaderGIF.Create;
	img:=TFPMemoryImage.Create(0,0);
	img.LoadFromFile(s,Reader);
	PTexture:=GetMem(img.Height*img.Width*4);
	t:=-1;
	for i:=img.height-1 downto 0 do
		for j:=0 to img.Width-1 do begin
			t:=t+1; PTexture[t]:=img.Colors[j,i].red;
			t:=t+1; PTexture[t]:=img.Colors[j,i].green;
			t:=t+1; PTexture[t]:=img.Colors[j,i].blue;
			t:=t+1; PTexture[t]:=img.Colors[j,i].alpha;
		end;
	img.Free; Reader.Free;
	glGenTextures(1,@texture);
	glBindTexture(GL_TEXTURE_2D,texture);
	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);
	glTexEnvf(GL_TEXTURE_ENV,GL_TEXTURE_ENV_MODE,GL_REPLACE);
	glTexImage2d(GL_TEXTURE_2D,0,GL_RGBA,img.Height,img.Width,0,GL_RGBA,
	             GL_UNSIGNED_BYTE,PTexture);
	exit(texture);
end;
{$ENDIF}