feat(math): integrate deterministic GameMath

Replaces standard CRT trigonometric functions with deterministic
fdlibm equivalents from GameMath via FetchContent.
Ensures multiplayer cross-platform replay determinism.

Resolves cross-platform mismatch disconnects.

Author: fbraz3

Core/Libraries/Source/WWVegas/WWMath/CMakeLists.txt

@@ -91,5 +91,11 @@ target_link_libraries(core_wwmath PRIVATE
     core_wwsaveload
 )
 
+if (SAGE_USE_DETERMINISTIC_MATH)
+    target_link_libraries(core_wwmath PUBLIC
+        gamemath
+    )
+endif()
+
 # @todo Test its impact and see what to do with the legacy functions.
 #add_compile_definitions(core_wwmath PUBLIC ALLOW_TEMPORARIES) # Enables legacy math with "temporaries"

Core/Libraries/Source/WWVegas/WWMath/wwmath.h

@@ -41,6 +41,14 @@
 #include <float.h>
 #include <assert.h>
 
+// Include GameMath headers when deterministic math is enabled
+// Use __has_include because wwmath.h is transitively included by targets that may not link gamemath.
+// Must be outside class WWMath to prevent injecting global symbols into the class.
+#if defined(__has_include) && __has_include("gmath.h")
+#include "gmath.h"
+#define USE_DETERMINISTIC_MATH (1)
+#endif
+
 /*
 ** Some global constants.
 */
@@ -139,19 +147,10 @@ static WWINLINE float Asin(float val);
 // Upstream reference: Okladnoj, PR #2670
 // https://github.com/TheSuperHackers/GeneralsGameCode/pull/2670
 
-// Include GameMath headers when deterministic math is enabled
-// Note: GameMath integration is pending. This header will be populated when
-// GameMath submodule or library is available. For now, wrappers fallback to CRT.
-#ifdef USE_DETERMINISTIC_MATH
-// TODO: Uncomment when GameMath library is integrated as submodule
-// #include "GameMath/deterministic_math.h"
-#endif
-
 static WWINLINE float		Atan(float x) 
 { 
 #ifdef USE_DETERMINISTIC_MATH
-	// TODO: return GameMath::Atan(x);
-	return static_cast<float>(atan(x)); 
+	return gm_atanf(x); 
 #else
 	return static_cast<float>(atan(x)); 
 #endif
@@ -160,8 +159,7 @@ static WWINLINE float		Atan(float x)
 static WWINLINE float		Atan2(float y, float x) 
 { 
 #ifdef USE_DETERMINISTIC_MATH
-	// TODO: return GameMath::Atan2(y, x);
-	return static_cast<float>(atan2(y, x)); 
+	return gm_atan2f(y, x); 
 #else
 	return static_cast<float>(atan2(y, x)); 
 #endif
@@ -172,28 +170,25 @@ static WWINLINE float		Atan2(float y, float x)
 static WWINLINE float SinTrig(float x) 
 { 
 #ifdef USE_DETERMINISTIC_MATH
-	// TODO: return GameMath::Sin(x);
-	return Sin(x); 
+	return gm_sinf(x); 
 #else
-	return Sin(x); 
+	return sinf(x); 
 #endif
 }
 
 static WWINLINE float CosTrig(float x) 
 { 
 #ifdef USE_DETERMINISTIC_MATH
-	// TODO: return GameMath::Cos(x);
-	return Cos(x); 
+	return gm_cosf(x); 
 #else
-	return Cos(x); 
+	return cosf(x); 
 #endif
 }
 
 static WWINLINE float TanTrig(float x) 
 { 
 #ifdef USE_DETERMINISTIC_MATH
-	// TODO: return GameMath::Tan(x);
-	return tanf(x); 
+	return gm_tanf(x); 
 #else
 	return tanf(x); 
 #endif
@@ -202,34 +197,37 @@ static WWINLINE float TanTrig(float x)
 static WWINLINE float ACosTrig(float x) 
 { 
 #ifdef USE_DETERMINISTIC_MATH
-	// TODO: return GameMath::Acos(x);
-	return Acos(x); 
+	return gm_acosf(x); 
 #else
-	return Acos(x); 
+	return acosf(x); 
 #endif
 }
 
 static WWINLINE float ASinTrig(float x) 
 { 
 #ifdef USE_DETERMINISTIC_MATH
-	// TODO: return GameMath::Asin(x);
-	return Asin(x); 
+	return gm_asinf(x); 
 #else
-	return Asin(x); 
+	return asinf(x); 
 #endif
 }
 
 // Phase 4: Origin sqrt gateway for geometry (Coord2D/Coord3D length calculations)
 // Must dispatch to deterministic Sqrt when enabled
-static WWINLINE double SqrtOrigin(double x) 
-{ 
-#ifdef USE_DETERMINISTIC_MATH
-	// TODO: return GameMath::Sqrt(x);
-	return sqrt(x); 
+// Origin wrappers: replace bare CRT math calls in GameLogic.
+// Each wrapper preserves the exact type (float vs double) of the vanilla CRT call.
+// Note: double overloads narrow to float before calling GameMath (gm_*f).
+// GameMath only provides float-precision functions. All call sites pass float-width
+// values, so the narrowing is lossless in practice.
+#if USE_DETERMINISTIC_MATH
+	static WWINLINE double		SqrtOrigin(double x) { return (double)gm_sqrtf((float)x); }
+	static WWINLINE float		SqrtfOrigin(float x) { return gm_sqrtf(x); }
+	static WWINLINE double		Atan2Origin(double y, double x) { return (double)gm_atan2f((float)y, (float)x); }
 #else
-	return sqrt(x); 
+	static WWINLINE double		SqrtOrigin(double x) { return sqrt(x); }
+	static WWINLINE float		SqrtfOrigin(float x) { return sqrtf(x); }
+	static WWINLINE double		Atan2Origin(double y, double x) { return atan2(y, x); }
 #endif
-}
 static WWINLINE float		Sign(float val);
 static WWINLINE float		Ceil(float val) { return ceilf(val); }
 static WWINLINE float		Floor(float val) { return floorf(val); }

cmake/gamemath.cmake

@@ -20,7 +20,7 @@
 # Enable deterministic math only for non-VC6 builds (VC6 uses native x87 asm)
 # Note: Currently defaults to OFF until GameMath is available as a proper library/submodule
 if(NOT IS_VS6_BUILD)
-    option(SAGE_USE_DETERMINISTIC_MATH "Use fdlibm-based deterministic math for cross-platform replay validation" OFF)
+    option(SAGE_USE_DETERMINISTIC_MATH "Use fdlibm-based deterministic math for cross-platform replay validation" ON)
 else()
     # VC6 uses native x87 inline asm; deterministic mode not applicable
     set(SAGE_USE_DETERMINISTIC_MATH OFF)
@@ -31,34 +31,23 @@ if(SAGE_USE_DETERMINISTIC_MATH)
 
     include(FetchContent)
 
-    # FetchContent declaration for GameMath library
-    # Source: TheSuperHackers fork with deterministic math support
-    # Can be overridden via cmake -DSAGE_GAMEMATH_GIT_REPO=<url> -DSAGE_GAMEMATH_GIT_TAG=<tag>
-    if(NOT SAGE_GAMEMATH_GIT_REPO)
-        set(SAGE_GAMEMATH_GIT_REPO "https://github.com/TheSuperHackers/GeneralsGameCode.git")
-    endif()
-    
-    if(NOT SAGE_GAMEMATH_GIT_TAG)
-        set(SAGE_GAMEMATH_GIT_TAG "main")
-    endif()
+    # FORCE is required to guarantee cross-platform bit-exact determinism.
+    # Intrinsics would use platform-specific SIMD, breaking CRC parity between architectures.
+    set(GM_ENABLE_INTRINSICS OFF CACHE BOOL "Disable intrinsics for cross-arch determinism" FORCE)
+    set(GM_ENABLE_TESTS OFF CACHE BOOL "Disable GameMath tests" FORCE)
 
     FetchContent_Declare(
         gamemath
-        GIT_REPOSITORY ${SAGE_GAMEMATH_GIT_REPO}
-        GIT_TAG ${SAGE_GAMEMATH_GIT_TAG}
-        SOURCE_SUBDIR "Core/GameMath"  # Adjust if GameMath moves
+        GIT_REPOSITORY https://github.com/TheSuperHackers/GameMath.git
+        GIT_TAG        59f7ccd494f7e7c916a784ac26ef266f9f09d78d
     )
 
-    # Minimal GameMath configuration
-    set(GAMEMATH_ENABLE_TESTS OFF CACHE BOOL "Disable GameMath tests" FORCE)
-    set(GAMEMATH_ENABLE_EXAMPLES OFF CACHE BOOL "Disable GameMath examples" FORCE)
-
     # Make GameMath available (FetchContent_MakeAvailable is idempotent)
     FetchContent_MakeAvailable(gamemath)
 
-    # Add USE_DETERMINISTIC_MATH to all compile definitions for this project
-    # This enables conditional compilation in wwmath.h and trig wrappers
-    add_compile_definitions(USE_DETERMINISTIC_MATH)
+    # Ensure GameMath includes are available to ALL targets
+    # to prevent one-definition-rule violations and ensure USE_DETERMINISTIC_MATH activates consistently.
+    include_directories(${gamemath_SOURCE_DIR}/include)
 
     message(STATUS "GameMath deterministic math enabled (fdlibm backend)")
     message(STATUS "  Math operations will be bit-exact across platforms")

flatpak/com.fbraz3.GeneralsX.yml

@@ -65,7 +65,8 @@ modules:
           -DFETCHCONTENT_SOURCE_DIR_SDL3_IMAGE=/run/build/generalsx/sdl3-image-src \
           -DFETCHCONTENT_SOURCE_DIR_OPENAL_SOFT=/run/build/generalsx/openal-soft-src \
           -DFETCHCONTENT_SOURCE_DIR_GAMESPY=/run/build/generalsx/gamespy-src \
-          -DFETCHCONTENT_SOURCE_DIR_LZHL=/run/build/generalsx/lzhl-src/CompLibHeader
+          -DFETCHCONTENT_SOURCE_DIR_LZHL=/run/build/generalsx/lzhl-src/CompLibHeader \
+          -DFETCHCONTENT_SOURCE_DIR_GAMEMATH=/run/build/generalsx/gamemath-src
       - cmake --build build-flatpak --target g_generals -j "${FLATPAK_BUILDER_N_JOBS:-4}"
       - cmake --build build-flatpak --target sage_patch -j "${FLATPAK_BUILDER_N_JOBS:-4}" || true
       - install -Dm755 build-flatpak/Generals/GeneralsX /app/bin/GeneralsX
@@ -185,3 +186,7 @@ modules:
         url: https://github.com/TheSuperHackers/lzhl-1.0
         commit: dfd96e2ca64adaddb35dd4ebadd6add7d5586783
         dest: lzhl-src/CompLibHeader
+      - type: git
+        url: https://github.com/TheSuperHackers/GameMath.git
+        commit: 59f7ccd494f7e7c916a784ac26ef266f9f09d78d
+        dest: gamemath-src

flatpak/com.fbraz3.GeneralsXZH.yml

@@ -65,7 +65,8 @@ modules:
           -DFETCHCONTENT_SOURCE_DIR_SDL3_IMAGE=/run/build/generalsxzh/sdl3-image-src \
           -DFETCHCONTENT_SOURCE_DIR_OPENAL_SOFT=/run/build/generalsxzh/openal-soft-src \
           -DFETCHCONTENT_SOURCE_DIR_GAMESPY=/run/build/generalsxzh/gamespy-src \
-          -DFETCHCONTENT_SOURCE_DIR_LZHL=/run/build/generalsxzh/lzhl-src/CompLibHeader
+          -DFETCHCONTENT_SOURCE_DIR_LZHL=/run/build/generalsxzh/lzhl-src/CompLibHeader \
+          -DFETCHCONTENT_SOURCE_DIR_GAMEMATH=/run/build/generalsxzh/gamemath-src
       - cmake --build build-flatpak --target z_generals -j "${FLATPAK_BUILDER_N_JOBS:-4}"
       - cmake --build build-flatpak --target sage_patch -j "${FLATPAK_BUILDER_N_JOBS:-4}" || true
       - install -Dm755 build-flatpak/GeneralsMD/GeneralsXZH /app/bin/GeneralsXZH
@@ -188,3 +189,7 @@ modules:
         url: https://github.com/TheSuperHackers/lzhl-1.0
         commit: dfd96e2ca64adaddb35dd4ebadd6add7d5586783
         dest: lzhl-src/CompLibHeader
+      - type: git
+        url: https://github.com/TheSuperHackers/GameMath.git
+        commit: 59f7ccd494f7e7c916a784ac26ef266f9f09d78d
+        dest: gamemath-src