{$DEFINE PNG_SCREENSHOTS}

uses typinfo, sysutils, uVariables, uUtils

     {$IFDEF PNG_SCREENSHOTS}, PNGh, png {$ENDIF}

     {$IFNDEF USE_SDLTHREADS} {$IFDEF UNIX}, cthreads{$ENDIF} {$ENDIF};

type PScreenshot = ^TScreenshot;

     TScreenshot = record

         buffer: PByte;

         filename: shortstring;

         width, height: LongInt;

         size: QWord;

         end;

{$IFDEF PNG_SCREENSHOTS}

// this funtion will be executed in separate thread

function SaveScreenshot(screenshot: pointer): PtrInt;

var i: LongInt;

    png_ptr: ^png_struct;

    info_ptr: ^png_info;

    image: PScreenshot;

begin

image:= PScreenshot(screenshot);

png_ptr := png_create_write_struct(png_get_libpng_ver(nil), nil, nil, nil);

if png_ptr = nil then

begin

    // AddFileLog('Error: Could not create png write struct.');

    exit(0);

end;

info_ptr := png_create_info_struct(png_ptr);

if info_ptr = nil then

begin

    png_destroy_write_struct(@png_ptr, nil);

    // AddFileLog('Error: Could not create png info struct.');

    exit(0);

end;

{$IOCHECKS OFF}

Assign(f, image^.filename);

Rewrite(f, 1);

if IOResult = 0 then

    begin

    png_init_pascal_io(png_ptr,@f);

    png_set_IHDR(png_ptr, info_ptr, image^.width, image^.height,

                 8, // bit depth

                 PNG_COLOR_TYPE_RGBA, PNG_INTERLACE_NONE,

                 PNG_COMPRESSION_TYPE_DEFAULT, PNG_FILTER_TYPE_DEFAULT);

    png_write_info(png_ptr, info_ptr);

    // glReadPixels and libpng number rows in different order

    for i:= image^.height-1 downto 0 do

        png_write_row(png_ptr, image^.buffer + i*4*image^.width);

    png_write_end(png_ptr, info_ptr);

    Close(f);

    end;

{$IOCHECKS ON}

// free everything

png_destroy_write_struct(@png_ptr, @info_ptr);

FreeMem(image^.buffer, image^.size);

Dispose(image);

SaveScreenshot:= 0;

end;

{$ELSE} // no PNG_SCREENSHOTS

// this funtion will be executed in separate thread

function SaveScreenshot(screenshot: pointer): PtrInt;

var f: file;

    image: PScreenshot;

    size: QWord;

begin

image:= PScreenshot(screenshot);

size:= image^.Width*image^.Height*4;

head[$02]:= (size + 54) and $ff;

head[$03]:= ((size + 54) shr 8) and $ff;

head[$04]:= ((size + 54) shr 16) and $ff;

head[$05]:= ((size + 54) shr 24) and $ff;

head[$12]:= image^.Width and $ff;

head[$13]:= (image^.Width shr 8) and $ff;

head[$14]:= (image^.Width shr 16) and $ff;

head[$15]:= (image^.Width shr 24) and $ff;

head[$16]:= image^.Height and $ff;

head[$17]:= (image^.Height shr 8) and $ff;

head[$18]:= (image^.Height shr 16) and $ff;

head[$19]:= (image^.Height shr 24) and $ff;

head[$22]:= size and $ff;

head[$23]:= (size shr 8) and $ff;

head[$24]:= (size shr 16) and $ff;

head[$25]:= (size shr 24) and $ff;

{$IOCHECKS OFF}

Assign(f, image^.filename);

Rewrite(f, 1);

if IOResult = 0 then

    begin

    BlockWrite(f, head, sizeof(head));

    BlockWrite(f, image^.buffer^, size);

    Close(f);

    end

else

    begin

    //AddFileLog('Error: Could not write to ' + filename);

    end;

{$IOCHECKS ON}

// free everything

FreeMem(image^.buffer, image^.size);

Dispose(image);

SaveScreenshot:= 0;

end;

{$ENDIF} // no PNG_SCREENSHOTS

// captures and saves the screen. returns true on success.

function MakeScreenshot(filename: shortstring): Boolean;

var p: Pointer;

    size: QWord;

    image: PScreenshot;

    format: GLenum;

    ext: string[4];

{$IFDEF PNG_SCREENSHOTS}

format:= GL_RGBA;

ext:= '.png';

{$ELSE}

format:= GL_BGRA;

ext:= '.bmp';

{$ENDIF}

p:= GetMem(size); // will be freed in SaveScreenshot()

// read pixel from the front buffer

glReadPixels(0, 0, cScreenWidth, cScreenHeight, format, GL_UNSIGNED_BYTE, p);

// allocate and fill structure that will be passed to new thread

New(image); // will be disposed in SaveScreenshot()

image^.filename:= UserPathPrefix + '/Screenshots/' + filename + ext;

image^.width:= cScreenWidth;

image^.height:= cScreenHeight;

image^.size:= size;

image^.buffer:= p;

{$IFDEF USE_SDLTHREADS}

SDL_CreateThread(@SaveScreenshot{$IFDEF SDL13}, nil{$ENDIF}, image);

{$ELSE}

BeginThread(@SaveScreenshot, image);

{$ENDIF}

MakeScreenshot:= true; // possibly it is not true but we will not wait for thread to terminate