REVIEWED: GetTime(), make it consistent between platforms, consider window initialization base time

Author: raysan5

src/platforms/rcore_desktop_glfw.c

@@ -1179,6 +1179,7 @@ void SwapScreenBuffer(void)
 double GetTime(void)
 {
     double time = glfwGetTime();   // Elapsed time since glfwInit()
+
     return time;
 }
 

src/platforms/rcore_desktop_rgfw.c

@@ -174,7 +174,6 @@ extern "C" {
 // Types and Structures Definition
 //----------------------------------------------------------------------------------
 typedef struct {
-    double startTime;
     RGFW_window *window;                // Native display device (physical screen connection)
     RGFW_monitor *monitor;
     mg_gamepads minigamepad;
@@ -1127,7 +1126,9 @@ void SwapScreenBuffer(void)
 // Get elapsed time measure in seconds since InitTimer()
 double GetTime(void)
 {
-    return get_time_seconds() - platform.startTime;
+    double time = get_time_seconds() - CORE.Time.base;
+
+    return time;
 }
 
 // Open URL with default system browser (if available)
@@ -1628,7 +1629,7 @@ int InitPlatform(void)
 
     RGFW_setGlobalHints_OpenGL(hints);
     platform.window = RGFW_createWindow((CORE.Window.title != 0)? CORE.Window.title : " ", 0, 0, CORE.Window.screen.width, CORE.Window.screen.height, flags | RGFW_windowOpenGL);
-    platform.startTime = get_time_seconds();
+    CORE.Time.base = get_time_seconds();
 
 #ifndef PLATFORM_WEB_RGFW
     i32 screenSizeWidth;

src/platforms/rcore_desktop_sdl.c

@@ -1276,7 +1276,9 @@ void SwapScreenBuffer(void)
 // Get elapsed time measure in seconds
 double GetTime(void)
 {
-    return (double)SDL_GetPerformanceCounter() / SDL_GetPerformanceFrequency();
+    double time = (double)(SDL_GetPerformanceCounter()/SDL_GetPerformanceFrequency()) - CORE.Time.base;
+
+    return time;
 }
 
 // Open URL with default system browser (if available)
@@ -2122,12 +2124,14 @@ int InitPlatform(void)
 
     // Initialize timing system
     //----------------------------------------------------------------------------
-    // NOTE: No need to call InitTimer(), let SDL manage it internally
-    CORE.Time.previous = GetTime();     // Get time as double
-
+    // Get base time from window initialization
+    CORE.Time.base = (double)(SDL_GetPerformanceCounter()/SDL_GetPerformanceFrequency());
+    
     #if defined(_WIN32) && SUPPORT_WINMM_HIGHRES_TIMER && !SUPPORT_BUSY_WAIT_LOOP
     SDL_SetHint(SDL_HINT_TIMER_RESOLUTION, "1"); // SDL equivalent of timeBeginPeriod() and timeEndPeriod()
     #endif
+    
+    // NOTE: No need to call InitTimer(), let SDL manage it internally
     //----------------------------------------------------------------------------
 
     // Initialize storage system

src/platforms/rcore_desktop_win32.c

@@ -1238,9 +1238,12 @@ void SwapScreenBuffer(void)
 // Get elapsed time measure in seconds
 double GetTime(void)
 {
+    double time = 0.0;
     LARGE_INTEGER now = { 0 };
     QueryPerformanceCounter(&now);
-    return (double)(now.QuadPart - CORE.Time.base)/(double)platform.timerFrequency.QuadPart;
+    time = (double)(now.QuadPart - CORE.Time.base)/(double)platform.timerFrequency.QuadPart;
+
+    return time;
 }
 
 // Open URL with default system browser (if available)

src/platforms/rcore_template.c

@@ -341,7 +341,6 @@ void SwapScreenBuffer(void)
 double GetTime(void)
 {
     double time = 0.0;
-
     struct timespec ts = { 0 };
     clock_gettime(CLOCK_MONOTONIC, &ts);
     unsigned long long int nanoSeconds = (unsigned long long int)ts.tv_sec*1000000000LLU + (unsigned long long int)ts.tv_nsec;

src/platforms/rcore_web.c

@@ -986,6 +986,7 @@ void SwapScreenBuffer(void)
 double GetTime(void)
 {
     double time = glfwGetTime();   // Elapsed time since glfwInit()
+
     return time;
 }
 

src/platforms/rcore_web_emscripten.c

@@ -962,14 +962,7 @@ void SwapScreenBuffer(void)
 // Get elapsed time measure in seconds since InitTimer()
 double GetTime(void)
 {
-    double time = 0.0;
-    /*
-    struct timespec ts = { 0 };
-    clock_gettime(CLOCK_MONOTONIC, &ts);
-    unsigned long long int nanoSeconds = (unsigned long long int)ts.tv_sec*1000000000LLU + (unsigned long long int)ts.tv_nsec;
-    time = (double)(nanoSeconds - CORE.Time.base)*1e-9;  // Elapsed time since InitTimer()
-    */
-    time = emscripten_get_now()*1000.0;
+    double time = emscripten_get_now()*1000.0;
 
     return time;
 }