Add 'dummy game' cgame module

This is a cgame module that simply loads and displays a map, with no
entities. It can be useful to quickly test how a map renders or to
make sure a simple gamelogic builds correctly in the CI.

CMakeLists.txt

@@ -147,6 +147,10 @@ option(USE_ADDRESS_SANITIZER "Try to use the address sanitizer" OFF)
 option(BE_VERBOSE "Tell the compiler to report all warnings" OFF)
 option(USE_STATIC_LIBS "Tries to use static libs where possible. Only works for Linux" OFF)
 
+if (NOT DAEMON_PARENT_SCOPE_DIR)
+    option(BUILD_DUMMY_GAMELOGIC "Build dummy cgame" OFF)
+endif()
+
 # Game VM modules are built with a recursive invocation of CMake, by which all the configuration
 # options are lost, except ones we explicitly choose to pass.
 set(DEFAULT_NACL_VM_INHERITED_OPTIONS
@@ -1058,3 +1062,7 @@ if (DEPS_DIR AND (BUILD_CLIENT OR BUILD_TTY_CLIENT OR BUILD_SERVER OR BUILD_DUMM
         endforeach()
     endif()
 endif()
+
+if (BUILD_DUMMY_GAMELOGIC)
+    include(src/dummygame/CMakeLists.txt)
+endif()

src/dummygame/CMakeLists.txt

@@ -0,0 +1,8 @@
+include(DaemonGame)
+
+GAMEMODULE(NAME cgame
+    FLAGS
+        ${WARNINGS}
+    FILES
+        src/dummygame/cgame.cpp
+)

src/dummygame/cgame.cpp

@@ -0,0 +1,214 @@
+/*
+===========================================================================
+Daemon BSD Source Code
+Copyright (c) 2024, Daemon Developers
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+* Redistributions of source code must retain the above copyright
+notice, this list of conditions and the following disclaimer.
+* Redistributions in binary form must reproduce the above copyright
+notice, this list of conditions and the following disclaimer in the
+documentation and/or other materials provided with the distribution.
+* Neither the name of the Daemon developers nor the
+names of its contributors may be used to endorse or promote products
+derived from this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
+ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+DISCLAIMED. IN NO EVENT SHALL DAEMON DEVELOPERS BE LIABLE FOR ANY
+DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+===========================================================================
+*/
+
+#include "common/Common.h"
+#include "engine/client/cg_msgdef.h"
+
+#include "shared/VMMain.h"
+#include "shared/CommandBufferClient.h"
+#include "shared/CommonProxies.h"
+#include "shared/client/cg_api.h"
+
+static bool mapLoaded;
+static vec3_t viewAngles;
+static refdef_t refdef;
+
+// Unvanquished default
+static Cvar::Cvar<float> dg_fovY("dg_fovY", "vertical field of view (degrees)", Cvar::NONE, 73.739792);
+// Unvanquished default at 4:3 aspect ratio
+static Cvar::Cvar<float> dg_fovX("dg_fovX", "horizontal field of view (degrees)", Cvar::NONE, 90);
+
+static Cvar::Cvar<int> dg_timeInitial(
+	"dg_timeInitial", "time to use for first frame of rendering", Cvar::NONE, 0);
+
+// There is no server time, and the client doesn't tell us what time it has
+static void UpdateTime()
+{
+	static int lastTime;
+	if (refdef.time == 0)
+		refdef.time = dg_timeInitial.Get();
+	int time = Sys::Milliseconds();
+	int fixedFrame;
+	if (Str::ParseInt(fixedFrame, Cvar::GetValue("common.fixedFrameTime")) && fixedFrame > 0) {
+		refdef.time += fixedFrame;
+	} else {
+		float timescale = 1;
+		Str::ToFloat(Cvar::GetValue("timescale"), timescale);
+		refdef.time += std::max<int>(1, timescale * (time - lastTime));
+	}
+	lastTime = time;
+}
+
+void VM::VMHandleSyscall(uint32_t id, Util::Reader reader) {
+	int major = id >> 16;
+	int minor = id & 0xffff;
+	if (major == VM::QVM) {
+		switch (minor) {
+		case CG_STATIC_INIT:
+			IPC::HandleMsg<CGameStaticInitMsg>(VM::rootChannel, std::move(reader), [] (int milliseconds) {
+				VM::InitializeProxies(milliseconds);
+				FS::Initialize();
+				cmdBuffer.Init();
+			});
+			break;
+
+		case CG_ROCKET_VM_INIT:
+			IPC::HandleMsg<CGameRocketInitMsg>(VM::rootChannel, std::move(reader), [] (const glconfig_t& gl) {
+				refdef.width = gl.vidWidth;
+				refdef.height = gl.vidHeight;
+			});
+			break;
+
+		case CG_ROCKET_FRAME:
+			IPC::HandleMsg<CGameRocketFrameMsg>(VM::rootChannel, std::move(reader), [] (const cgClientState_t&) {
+				if (mapLoaded) {
+					refdef.fov_x = dg_fovX.Get();
+					refdef.fov_y = dg_fovY.Get();
+					AnglesToAxis(viewAngles, refdef.viewaxis);
+					UpdateTime();
+					trap_R_RenderScene(&refdef);
+				} else {
+					trap_R_SetColor(Color::MdGrey);
+					static qhandle_t h = trap_R_RegisterShader("white", RSF_DEFAULT);
+					trap_R_DrawStretchPic(0, 0, refdef.width, refdef.height, 0, 0, 1, 1, h);
+				}
+
+				cmdBuffer.TryFlush();
+			});
+			break;
+
+		case CG_KEY_DOWN_EVENT: // only engine->cgame call with a reply
+			IPC::HandleMsg<CGameKeyDownEventMsg>(VM::rootChannel, std::move(reader), [] (Keyboard::Key, bool, bool& consumed) {
+				consumed = false;
+			});
+			break;
+
+		default:
+			{
+				Util::Writer writer;
+				writer.Write<uint32_t>(IPC::ID_RETURN);
+				VM::rootChannel.SendMsg(writer);
+			}
+			break;
+		}
+	} else if (major < VM::LAST_COMMON_SYSCALL) {
+		VM::HandleCommonSyscall(major, minor, std::move(reader), VM::rootChannel);
+	} else {
+		Sys::Drop("unhandled VM major syscall number %i", major);
+	}
+}
+
+class LoadMapCmd : public Cmd::StaticCmd
+{
+public:
+	LoadMapCmd() : StaticCmd("loadmap", "load a map for viewing") {}
+
+	void Run(const Cmd::Args& args) const override
+	{
+		if (args.Argc() == 2) {
+			const FS::PakInfo* pak = FS::FindPak("map-" + args.Argv(1));
+			if (!pak) {
+				Print("map %s not found", args.Argv(1));
+				return;
+			}
+
+			if (mapLoaded) {
+				// need to restart FS
+				trap_SendConsoleCommand(Str::Format(
+					"disconnect\nloadmap %s", Cmd::Escape(args.Argv(1))).c_str());
+			} else {
+				FS::PakPath::LoadPak(*pak);
+				// need to restart renderer because shader scanning was done earlier, but
+				// WITHOUT restarting the filesystem
+				trap_SendConsoleCommand(Str::Format(
+					"vid_restart\nloadmap -restarted %s", Cmd::Escape(args.Argv(1))).c_str());
+			}
+		} else if (args.Argc() == 3 && Str::IsIEqual(args.Argv(1), "-restarted")) {
+			// All layers of the color grade image are pre-populated with a neutral cgrade when
+			// the renderer starts (though there is no way to get it back later)
+			refdef.gradingWeights[0] = 1.0f;
+
+			trap_R_LoadWorldMap(("maps/" + args.Argv(2) + ".bsp").c_str());
+
+			// This is done by EndRegistration but there is no way to invoke that
+			bool reflection;
+			if (Cvar::ParseCvarValue(Cvar::GetValue("r_reflectionMapping"), reflection)
+			    && reflection) {
+				trap_SendConsoleCommand("buildcubemaps");
+			}
+
+			mapLoaded = true;
+		} else {
+			PrintUsage(args, "<map name>");
+		}
+	}
+};
+static LoadMapCmd loadmapRegistration;
+
+class SetViewPosCmd : public Cmd::StaticCmd
+{
+public:
+	SetViewPosCmd() : StaticCmd("setviewpos", "set viewing position & angle") {}
+
+	void Run(const Cmd::Args& args) const override
+	{
+		if (args.Argc() < 2 || args.Argc() > 7) {
+			PrintUsage(args, "x y z yaw pitch roll",
+				"All arguments are optional. '-' can be used instead of a number to not set one.");
+			return;
+		}
+
+		// Although PITCH is 0 and YAW is 1, we use the order yaw,pitch,roll which matches
+		// Unvanquished, and is also the order the rotations are actually applied in
+		float* values[6] { refdef.vieworg + 0, refdef.vieworg + 1, refdef.vieworg + 2,
+		                   viewAngles + YAW, viewAngles + PITCH, viewAngles + ROLL };
+
+		for (int i = 0; i < args.Argc() - 1; i++) {
+			if (args.Argv(i + 1) != "-" && !Str::ToFloat(args.Argv(i + 1), *values[i])) {
+				Print("invalid number '%s'", args.Argv(i + 1));
+			}
+		}
+	}
+};
+static SetViewPosCmd setviewposRegistration;
+
+bool ConsoleCommand()
+{
+	ASSERT_UNREACHABLE();
+}
+void CompleteCommand(int)
+{
+	ASSERT_UNREACHABLE();
+}
+
+void VM::GetNetcodeTables(NetcodeTable&, int&)
+{
+	Sys::Drop("GetNetcodeTables not implemented");
+}