Angle に 0 を指定すれば回転はしないです。
//- 以下、テストコード ("test1.bmp"を使用) -//
#include "DxLib.h"
int WINAPI WinMain( HINSTANCE, HINSTANCE, LPSTR, int )
{
ChangeWindowMode( TRUE );
if ( DxLib_Init( ) == -1 ) return -1;
int w, h;
int gh = LoadGraph( "test1.bmp" );
GetGraphSize( gh, &w, &h );
w /= 2; h /= 2;
SetDrawScreen( DX_SCREEN_BACK );
while ( ProcessMessage( ) == 0 && CheckHitKey( KEY_INPUT_ESCAPE ) == 0 ) {
ClearDrawScreen( );
DrawGraph( 0, 0, gh, TRUE );
DrawRotaGraph( 200 + w, 0 + h, 1.5, 0, gh, TRUE, FALSE );
DrawRotaGraph( 400 + w, 0 + h, 1.5, 0, gh, TRUE, TRUE );
ScreenFlip( );
}
DxLib_End( );
return 0;
}