Add VGUI HUD overlay drawing feature

Currently only supports Orange Box and Left 4 Dead branches. There's
quite a large amount of gamedata involved in making this work, and
figuring it out for the likes of Portal 2 doesn't seem like a major
priority at the moment.

7 files changed, 373 insertions, 2 deletions

diff --git a/compile b/compile
index c7014e8..abdd5a7 100755
--- a/compile
+++ b/compile
@@ -71,6 +71,7 @@ src="\
 	gameinfo.c
 	gameserver.c
 	hook.c
+	hud.c
 	kvsys.c
 	l4dmm.c
 	l4dreset.c
@@ -92,7 +93,7 @@ $HOSTCC -O2 -fuse-ld=lld $warnings -D_FILE_OFFSET_BITS=64 -include stdbool.h \
 		-o .build/mkentprops src/build/mkentprops.c src/kv.c
 .build/codegen `for s in $src; do echo "src/$s"; done`
 .build/mkgamedata gamedata/engine.kv gamedata/gamelib.kv gamedata/inputsystem.kv \
-		gamedata/matchmaking.kv
+gamedata/matchmaking.kv gamedata/vgui2.kv gamedata/vguimatsurface.kv
 .build/mkentprops gamedata/entprops.kv
 for s in $src; do cc "$s"; done
 $CC -shared -fpic -fuse-ld=lld -O0 -w -o .build/libtier0.so src/stubs/tier0.c
diff --git a/compile.bat b/compile.bat
index 8db2231..97bbb6f 100644
--- a/compile.bat
+++ b/compile.bat
@@ -78,6 +78,7 @@ setlocal DisableDelayedExpansion
 :+ gameinfo.c

 :+ gameserver.c

 :+ hook.c

+:+ hud.c

 :+ kvsys.c

 :+ l4dmm.c

 :+ l4dreset.c

@@ -100,7 +101,8 @@ if "%dbg%"=="0" set src=%src% src/wincrt.c
 %HOSTCC% -fuse-ld=lld -municode -O2 %warnings% -D_CRT_SECURE_NO_WARNINGS -include stdbool.h -ladvapi32 ^

 -o .build/mkentprops.exe src/build/mkentprops.c src/kv.c || exit /b

 .build\codegen.exe%src% || exit /b

-.build\mkgamedata.exe gamedata/engine.kv gamedata/gamelib.kv gamedata/inputsystem.kv gamedata/matchmaking.kv || exit /b

+.build\mkgamedata.exe gamedata/engine.kv gamedata/gamelib.kv gamedata/inputsystem.kv ^

+gamedata/matchmaking.kv gamedata/vgui2.kv gamedata/vguimatsurface.kv || exit /b

 .build\mkentprops.exe gamedata/entprops.kv || exit /b

 llvm-rc /FO .build\dll.res src\dll.rc || exit /b

 %CC% -fuse-ld=lld -shared -O0 -w -o .build/tier0.dll src/stubs/tier0.c

diff --git a/gamedata/engine.kv b/gamedata/engine.kv
index 9501221..b23bab5 100644
--- a/gamedata/engine.kv
+++ b/gamedata/engine.kv
@@ -63,6 +63,31 @@ sz_edict {
 	L4Dbased 16 // see engineapi.h comment
 }
 
+// vgui::Panel
+vtidx_SetPaintEnabled {
+	default 67
+	Client013 {
+		L4D1 68
+		L4D2 {
+			default 71
+			L4D2_2147plus 72
+		}
+	}
+	Client014 {
+		L4D2 70
+	}
+}
+vtidx_Paint {
+	default 123
+	Client014 { L4D2 126 } // 2000
+	Client013 {
+		L4D2 {
+			default 127 // 2045
+			L4D2_2147plus 128
+		}
+	}
+}
+
 // SendProp
 sz_SendProp {
 	// wrapping all these in 005 for right now.
@@ -104,6 +129,7 @@ vtidx_GetSpawnCount {
 }
 
 // IEngineVGuiInternal/CEngineVGui
+vtidx_GetPanel NVDTOR
 vtidx_VGuiConnect { // note: the actual name is Connect() but that's too generic
 	default "3 + NVDTOR"
 	L4Dbased {
diff --git a/gamedata/vgui2.kv b/gamedata/vgui2.kv
new file mode 100644
index 0000000..6fd55a3
--- /dev/null
+++ b/gamedata/vgui2.kv
@@ -0,0 +1,7 @@
+// = vgui2 library =
+
+// ISchemeManager
+vtidx_GetIScheme 8
+
+// IScheme
+vtidx_GetFont 3
diff --git a/gamedata/vguimatsurface.kv b/gamedata/vguimatsurface.kv
new file mode 100644
index 0000000..19857be
--- /dev/null
+++ b/gamedata/vguimatsurface.kv
@@ -0,0 +1,69 @@
+// = vguimatsurface library =
+
+// ISurface
+vtidx_DrawSetColor {
+	OrangeBoxbased 10
+	L4D 10
+}
+vtidx_DrawFilledRect {
+	OrangeBoxbased 12
+	L4D 12
+}
+vtidx_DrawOutlinedRect {
+	OrangeBoxbased 14
+	L4D 14
+}
+vtidx_DrawLine {
+	OrangeBoxbased 15
+	L4D 15
+}
+vtidx_DrawPolyLine {
+	OrangeBoxbased 16
+	L4D 16
+}
+vtidx_DrawSetTextFont {
+	OrangeBoxbased 17
+	L4D 17
+}
+vtidx_DrawSetTextColor {
+	OrangeBoxbased 18
+	L4D 18
+}
+vtidx_DrawSetTextPos {
+	OrangeBoxbased 20
+	L4D 20
+}
+vtidx_DrawPrintText {
+	OrangeBoxbased 22
+	L4D 22
+}
+vtidx_GetScreenSize {
+	OrangeBoxbased 37
+	L4D {
+		default 37
+		L4D2_2147plus 35
+	}
+}
+// Unused: currently no good way to create custom fonts without leaking them
+//vtidx_CreateFont {
+//	OrangeBoxbased 64
+//	L4D {
+//		default 64
+//		L4D2_2147plus 63
+//	}
+//}
+//vtidx_SetFontGlyphSet {
+//	OrangeBoxbased 65
+//	L4D {
+//		default 65
+//		L4D2_2147plus 64
+//	}
+//}
+vtidx_GetFontTall {
+	OrangeBoxbased 67
+	L4D 67
+}
+vtidx_GetCharacterWidth {
+	OrangeBoxbased 71
+	L4D 71
+}
diff --git a/src/hud.c b/src/hud.c
new file mode 100644
index 0000000..8176d63
--- /dev/null
+++ b/src/hud.c
@@ -0,0 +1,194 @@
+/*
+ * Copyright © 2022 Matthew Wozniak <sirtomato999@gmail.com>
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED “AS IS” AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH
+ * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
+ * AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
+ * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
+ * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
+ * OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
+ * PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#include "engineapi.h"
+#include "errmsg.h"
+#include "event.h"
+#include "feature.h"
+#include "gamedata.h"
+#include "gametype.h"
+#include "hook.h"
+#include "hud.h"
+#include "intdefs.h"
+#include "mem.h"
+#include "os.h"
+#include "sst.h"
+#include "vcall.h"
+#include "x86.h"
+#include "x86util.h"
+
+FEATURE()
+REQUIRE_GLOBAL(factory_engine)
+REQUIRE_GLOBAL(vgui)
+// ISurface
+REQUIRE_GAMEDATA(vtidx_DrawSetColor)
+REQUIRE_GAMEDATA(vtidx_DrawFilledRect)
+REQUIRE_GAMEDATA(vtidx_DrawOutlinedRect)
+REQUIRE_GAMEDATA(vtidx_DrawLine)
+REQUIRE_GAMEDATA(vtidx_DrawPolyLine)
+REQUIRE_GAMEDATA(vtidx_DrawSetTextFont)
+REQUIRE_GAMEDATA(vtidx_DrawSetTextColor)
+REQUIRE_GAMEDATA(vtidx_DrawSetTextPos)
+REQUIRE_GAMEDATA(vtidx_DrawPrintText)
+REQUIRE_GAMEDATA(vtidx_GetScreenSize)
+REQUIRE_GAMEDATA(vtidx_GetFontTall)
+REQUIRE_GAMEDATA(vtidx_GetCharacterWidth)
+// CEngineVGui
+REQUIRE_GAMEDATA(vtidx_GetPanel)
+// vgui::Panel
+REQUIRE_GAMEDATA(vtidx_SetPaintEnabled)
+REQUIRE_GAMEDATA(vtidx_Paint)
+// ISchemeManager
+REQUIRE_GAMEDATA(vtidx_GetIScheme)
+// IScheme
+REQUIRE_GAMEDATA(vtidx_GetFont)
+
+DEF_EVENT(HudPaint, void)
+
+// we just use ulongs for API, but keep a struct for vcalls to ensure we get the
+// right calling convention (x86 Windows/MSVC is funny about passing structs...)
+struct handlewrap { ulong x; };
+
+// CEngineVGui
+DECL_VFUNC_DYN(unsigned int, GetPanel, int)
+
+// vgui::ISchemeManager
+DECL_VFUNC_DYN(void *, GetIScheme, struct handlewrap)
+// vgui::IScheme
+DECL_VFUNC_DYN(struct handlewrap, GetFont, const char *, bool)
+
+// vgui::ISurface
+DECL_VFUNC_DYN(void, DrawSetColor, struct rgba)
+DECL_VFUNC_DYN(void, DrawFilledRect, int, int, int, int)
+DECL_VFUNC_DYN(void, DrawOutlinedRect, int, int, int, int)
+DECL_VFUNC_DYN(void, DrawLine, int, int, int, int)
+DECL_VFUNC_DYN(void, DrawPolyLine, int *, int *, int)
+DECL_VFUNC_DYN(void, DrawSetTextFont, struct handlewrap)
+DECL_VFUNC_DYN(void, DrawSetTextColor, struct rgba)
+DECL_VFUNC_DYN(void, DrawSetTextPos, int, int)
+DECL_VFUNC_DYN(void, DrawPrintText, ushort *, int, int)
+DECL_VFUNC_DYN(void, GetScreenSize, int *, int *)
+DECL_VFUNC_DYN(int, GetFontTall, struct handlewrap)
+DECL_VFUNC_DYN(int, GetCharacterWidth, struct handlewrap, int)
+
+// vgui::Panel
+DECL_VFUNC_DYN(void, SetPaintEnabled, bool)
+
+static void *matsurf, *toolspanel, *scheme;
+
+typedef void (*VCALLCONV Paint_func)(void *);
+static Paint_func orig_Paint;
+void VCALLCONV hook_Paint(void *this) {
+	if (this == toolspanel) EMIT_HudPaint();
+	orig_Paint(this);
+}
+
+ulong hud_getfont(const char *name, bool proportional) {
+	return GetFont(scheme, name, proportional).x;
+}
+
+void hud_drawrect(int x0, int y0, int x1, int y1, struct rgba colour,
+		bool fill) {
+	DrawSetColor(matsurf, colour);
+	if (fill) DrawFilledRect(matsurf, x0, y0, x1, y1);
+	else DrawOutlinedRect(matsurf, x0, y0, x1, y1);
+}
+
+void hud_drawline(int x0, int y0, int x1, int y1, struct rgba colour) {
+	DrawSetColor(matsurf, colour);
+	DrawLine(matsurf, x0, y0, x1, y1);
+}
+
+void hud_drawpolyline(int *x, int *y, int npoints, struct rgba colour) {
+	DrawSetColor(matsurf, colour);
+	DrawPolyLine(matsurf, x, y, npoints);
+}
+
+void hud_drawtext(ulong font, int x, int y, struct rgba colour, ushort *str,
+		int len) {
+	DrawSetTextFont(matsurf, (struct handlewrap){font});
+	DrawSetTextPos(matsurf, x, y);
+	DrawSetTextColor(matsurf, colour);
+	DrawPrintText(matsurf, str, len, /*FONT_DRAW_DEFAULT*/ 0);
+}
+
+void hud_screensize(int *width, int *height) {
+	GetScreenSize(matsurf, width, height);
+}
+
+int hud_fontheight(ulong font) {
+	return GetFontTall(matsurf, (struct handlewrap){font});
+}
+
+int hud_charwidth(ulong font, int ch) {
+	return GetCharacterWidth(matsurf, (struct handlewrap){font}, ch);
+}
+
+static bool find_toolspanel(void *enginevgui) {
+	const uchar *insns = (const uchar *)VFUNC(enginevgui, GetPanel);
+	for (const uchar *p = insns; p - insns < 16;) {
+		// first CALL instruction in GetPanel calls GetRootPanel, which gives a
+		// pointer to the specified panel
+		if (p[0] == X86_CALL) {
+			typedef void *(*VCALLCONV GetRootPanel_func)(void *this, int);
+			int off = mem_load32(p + 1);
+			GetRootPanel_func GetRootPanel = (GetRootPanel_func)(p + 5 + off);
+			toolspanel = GetRootPanel(enginevgui, /*PANEL_TOOLS*/ 3);
+			return true;
+		}
+		NEXT_INSN(p, "GetRootPanel function");
+	}
+	return false;
+}
+
+INIT {
+	matsurf = factory_engine("MatSystemSurface006", 0);
+	if (!matsurf) {
+		errmsg_errorx("couldn't get MatSystemSurface006 interface");
+		return false;
+	}
+	void *schememgr = factory_engine("VGUI_Scheme010", 0);
+	if (!schememgr) {
+		errmsg_errorx("couldn't get VGUI_Scheme010 interface");
+		return false;
+	}
+	if (!find_toolspanel(vgui)) {
+		errmsg_errorx("couldn't find engine tools panel");
+		return false;
+	}
+	void **vtable = *(void ***)toolspanel;
+	if (!os_mprot(vtable + vtidx_Paint, sizeof(void *),
+			PAGE_READWRITE)) {
+		errmsg_errorsys("couldn't make virtual table writable");
+		return false;
+	}
+	orig_Paint = (Paint_func)hook_vtable(vtable, vtidx_Paint,
+			(void *)&hook_Paint);
+	SetPaintEnabled(toolspanel, true);
+	// 1 is the default, first loaded scheme. should always be sourcescheme.res
+	scheme = GetIScheme(schememgr, (struct handlewrap){1});
+	return true;
+}
+
+END {
+	// don't unhook toolspanel if exiting, it's already long gone!
+	if (sst_userunloaded) {
+		unhook_vtable(*(void ***)toolspanel, vtidx_Paint, (void *)orig_Paint);
+		SetPaintEnabled(toolspanel, false);
+	}
+}
+
+// vi: sw=4 ts=4 noet tw=80 cc=80
diff --git a/src/hud.h b/src/hud.h
new file mode 100644
index 0000000..8ea0877
--- /dev/null
+++ b/src/hud.h
@@ -0,0 +1,72 @@
+/*
+ * Copyright © 2022 Matthew Wozniak <sirtomato999@gmail.com>
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED “AS IS” AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH
+ * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
+ * AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
+ * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
+ * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
+ * OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
+ * PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#ifndef INC_HUD_H
+#define INC_HUD_H
+
+#include "event.h"
+#include "engineapi.h"
+#include "intdefs.h"
+
+/*
+ * Emitted when the game HUD is being drawn. Allows features to draw their own
+ * additional overlays atop the game's standard HUD.
+ */
+DECL_EVENT(HudPaint, void)
+
+/* Font style flags */
+#define HUD_FONT_ITALIC 1
+#define HUD_FONT_UNDERLINE 2
+#define HUD_FONT_STRIKE 4
+#define HUD_FONT_SYMBOL 8
+#define HUD_FONT_AA 16
+#define HUD_FONT_GAUSSBLUR 32
+#define HUD_FONT_ROTARY 64
+#define HUD_FONT_DROPSHADOW 128
+#define HUD_FONT_ADDITIVE 256
+#define HUD_FONT_OUTLINE 512
+#define HUD_FONT_CUSTOM 1024
+#define HUD_FONT_BITMAP 2048
+
+/* Gets a font handle by its name in sourcescheme.res. */
+ulong hud_getfont(const char *name, bool proportional);
+
+/* Sets the drawing pen colour for subsequent HUD drawing calls (below). */
+void hud_setcolour(struct rgba colour);
+
+/* Draws a rectangle on top of the HUD. */
+void hud_drawrect(int x0, int y0, int x1, int y1, struct rgba colour, bool fill);
+
+/* Draws a line on top of the HUD. */
+void hud_drawline(int x0, int y0, int x1, int y1, struct rgba colour);
+
+/* Draws an arbitrary series of lines between an array of points. */
+void hud_drawpolyline(int *xs, int *ys, int npoints, struct rgba colour);
+
+/* Draws text using a given font handle. */
+void hud_drawtext(ulong font, int x, int y, struct rgba colour, ushort *str,
+		int len);
+
+/* Returns the width and height of the game window in pixels. */
+void hud_screensize(int *width, int *height);
+
+/* Returns the height of a font, in pixels. */
+int hud_fontheight(ulong font);
+
+/* Returns the width of a font character, in pixels. */
+int hud_getcharwidth(ulong font, int ch);
+
+#endif