# VGUI Screen Creation

## Adding a VGUI screen to map

Note: This section assumes a mod where VGUI screens have been fixed (see the code modifications section below) but otherwise left the same. VGUI screens do not work in HL2 or HL2:DM; they crash the game. (CS:S not tested.)
1. Create a vgui_screen entity. This is a point entity.
2. Set its Panel Name to the name of the screen that should be shown. (This is not the filename of the screen.) The available screens are listed in vgui_screens.txt (which should be in the scripts directory).
3. Set Panel Width in World and Panel Height in World to match the size of the brush. 64 wide by 32 tall would be a reasonable starting size.
4. Compile the map and test.

The position of the entity in the map marks the bottom-left corner of the panel. The panel's direction (the normal of its face) is set by the entity's angle (Yaw).

## Creating a VGUI screen

VGUI screen files have a .res extension and should be placed in scripts\screens\.

1. vgui_test_screen.res is a good starting point for creating a VGUI screen file; it can be extracted from source engine.gcf at path hl2/scripts/screens/ using GCFScape.
2. The materials used in the .res file can be found in source materials.gcf. Extract the material files mentioned in the .res file to materials\vgui\screens\.
3. Add the screen to scripts\vgui_screens.txt. If it does not exist, create it. Here is an example which describes screen vgui_test_screen at scripts/screens/vgui_test_screen.res. Adjust it for your screen.
"VGUI_Screens"
{
"vgui_test_screen"
{
// This is our example screen
"type"		"vgui_screen_panel"
"pixelswide"	480
"pixelshigh"	240
// This must be the file you created in step 1
"resfile"	"scripts/screens/vgui_test_screen.res"
}
}


An example vgui_screen.txt file can be extracted from source engine.gcf at root/hl2/scripts.

## VGUI code modifications

There is a problem with VGUI screens receiving input. Unless it is fixed, the game may crash when the cursor points at the screen.

CInput::ExtraMouseSample calls g_pClientMode->CreateMove() without initializing the button flags, thus the VGui screen is updated with bad button input. Since IN_VALIDVGUIINPUT is only set from within CInput::CreateMove, the VGui screens only update when the button flags are valid.

There are two known fixes. They both involve code changes and therefore are only applicable to mods.

### Fix 1

In src\game_shared\in_buttons.h, where the other flags are defined add:

   #define IN_VALIDVGUIINPUT		    (1 << 23) //bitflag for vgui fix


next, in src\cl_dll\in_main.cpp inside method CInput::CreateMove ( ... ) add:

   cmd->buttons |= IN_VALIDVGUIINPUT;


right above:

   g_pClientMode->CreateMove( input_sample_frametime, cmd );


next, in src\cl_dll\c_baseplayer.cpp inside method C_BasePlayer::CreateMove( ... ) add:

   if(pCmd->buttons & IN_VALIDVGUIINPUT)


right above:

   DetermineVguiInputMode( pCmd );


(So it only calls DetermineVguiInputMode if the buttons include our flag)

and finally, inside method C_BasePlayer::DetermineVguiInputMode( ... ) change both instances of:

   pCmd->buttons &= ~(IN_ATTACK | IN_ATTACK2);


   pCmd->buttons &= ~(IN_ATTACK | IN_ATTACK2 | IN_VALIDVGUIINPUT);


Since an HL2 engine update in October VGUI Screens will crash when you put your mouse over them. This is because the g_InputInternal function used in \src\cl_dll\c_vguiscreen.cpp is no longer working. Trying to access it makes it crash. For a workaround, the following C_VGuiScreen::ClientThink( void ) function has proven useful:

	// Convert (u,v) into (px,py)
int px = (int)(u * m_nPixelWidth + 0.5f);
int py = (int)(v * m_nPixelHeight + 0.5f);

// START TEDDYS FIX
for (int i = 0; i < pPanel->GetChildCount(); i++)
{
vgui::Button *child = dynamic_cast<vgui::Button*>(pPanel->GetChild(i));
if ( child )
{
int x1, x2, y1, y2;
child->GetBounds( x1, y1, x2, y2 );

// Generate mouse input commands
if ( (m_nButtonState & IN_ATTACK) )
{
if ( px >= x1 && px <= x1 + x2 && py >= y1 && py <= y1 + y2 )
child->FireActionSignal();
}
}
}
// FIN TEDDYS FIX

if ( m_bLooseThinkNextFrame == true )
{
m_bLooseThinkNextFrame = false;
SetNextClientThink( CLIENT_THINK_NEVER );
}


### Fix 2

An alternative fix would be to add a new boolean variable to CUserCmd such as bButtonFlagsValid that can be set depending on the validity of the button flags. This would allow the structure to internally store this information for its whole lifetime while freeing up that extra button bit.

## Example screenshots

VGUI screen used in mod
VGUI screen used to display dynamically drawn EKG data