[examples] models_animation_blending: avoid crash when animations fail to load (#6234)

If resources/models/gltf/robot.glb can't be found (e.g. the example is
run from another working directory), LoadModelAnimations() returns NULL
with animCount = 0 and the example indexed anims[] in the update loop
and in the timeline drawing, crashing. Skip both when no animations
were loaded, so it just logs the usual load warnings.

Reported in #5664.

examples/models/models_animation_blending.c

@@ -114,7 +114,7 @@ int main(void)
 
         if (IsKeyPressed(KEY_P)) animPause = !animPause;
 
-        if (!animPause)
+        if (!animPause && (animCount > 0)) // Animations could fail to load
         {
             // Start transition from anim0[] to anim1[]
             if (IsKeyPressed(KEY_SPACE) && !animTransition)
@@ -256,21 +256,24 @@ int main(void)
             GuiSetStyle(DEFAULT, TEXT_SIZE, GuiGetFont().baseSize);
             GuiSetStyle(LABEL, TEXT_ALIGNMENT, TEXT_ALIGN_LEFT);
 
-            // Draw playing timeline with keyframes for anim0[]
+            if (animCount > 0)
-            GuiProgressBar((Rectangle){ 60, GetScreenHeight() - 60.0f, GetScreenWidth() - 180.0f, 20 }, "ANIM 0",
+            {
-                TextFormat("FRAME: %.2f / %i", animFrameProgress0, anims[animIndex0].keyframeCount),
+                // Draw playing timeline with keyframes for anim0[]
-                &animFrameProgress0, 0.0f, (float)anims[animIndex0].keyframeCount);
+                GuiProgressBar((Rectangle){ 60, GetScreenHeight() - 60.0f, GetScreenWidth() - 180.0f, 20 }, "ANIM 0",
-            for (int i = 0; i < anims[animIndex0].keyframeCount; i++)
+                    TextFormat("FRAME: %.2f / %i", animFrameProgress0, anims[animIndex0].keyframeCount),
-                DrawRectangle(60 + (int)(((float)(GetScreenWidth() - 180)/(float)anims[animIndex0].keyframeCount)*(float)i),
+                    &animFrameProgress0, 0.0f, (float)anims[animIndex0].keyframeCount);
-                    GetScreenHeight() - 60, 1, 20, BLUE);
+                for (int i = 0; i < anims[animIndex0].keyframeCount; i++)
+                    DrawRectangle(60 + (int)(((float)(GetScreenWidth() - 180)/(float)anims[animIndex0].keyframeCount)*(float)i),
+                        GetScreenHeight() - 60, 1, 20, BLUE);
 
-            // Draw playing timeline with keyframes for anim1[]
+                // Draw playing timeline with keyframes for anim1[]
-            GuiProgressBar((Rectangle){ 60, GetScreenHeight() - 30.0f, GetScreenWidth() - 180.0f, 20 }, "ANIM 1",
+                GuiProgressBar((Rectangle){ 60, GetScreenHeight() - 30.0f, GetScreenWidth() - 180.0f, 20 }, "ANIM 1",
-                TextFormat("FRAME: %.2f / %i", animFrameProgress1, anims[animIndex1].keyframeCount),
+                    TextFormat("FRAME: %.2f / %i", animFrameProgress1, anims[animIndex1].keyframeCount),
-                &animFrameProgress1, 0.0f, (float)anims[animIndex1].keyframeCount);
+                    &animFrameProgress1, 0.0f, (float)anims[animIndex1].keyframeCount);
-            for (int i = 0; i < anims[animIndex1].keyframeCount; i++)
+                for (int i = 0; i < anims[animIndex1].keyframeCount; i++)
-                DrawRectangle(60 + (int)(((float)(GetScreenWidth() - 180)/(float)anims[animIndex1].keyframeCount)*(float)i),
+                    DrawRectangle(60 + (int)(((float)(GetScreenWidth() - 180)/(float)anims[animIndex1].keyframeCount)*(float)i),
-                    GetScreenHeight() - 30, 1, 20, BLUE);
+                        GetScreenHeight() - 30, 1, 20, BLUE);
+            }
             //---------------------------------------------------------------------------------------------
 
         EndDrawing();

src/platforms/rcore_desktop_win32.c

@@ -393,7 +393,7 @@ static bool UpdateWindowSize(int mode, HWND hwnd, int width, int height, unsigne
     SIZE clientSize = { rect.right, rect.bottom };
 
     // If client size is alread desired size, no need to update
-    if ((clientSize.cx == desiredSize.cx) || (clientSize.cy == desiredSize.cy)) return false;
+    if ((clientSize.cx == desiredSize.cx) && (clientSize.cy == desiredSize.cy)) return false;
 
     TRACELOG(LOG_INFO, "WIN32: Restoring client size from [%dx%d] to [%dx%d] (dpi:%lu dpiScaling:%d app:%ix%i)",
         clientSize.cx, clientSize.cy, desiredSize.cx, desiredSize.cy, dpi, dpiScaling, width, height);
@@ -1767,12 +1767,31 @@ int InitPlatform(void)
 // Close platform
 void ClosePlatform(void)
 {
+    // Undo disable cursor if it's locked and unregister raw input devices
+    EnableCursor();
+
+    // Calling DestroyWindow invokes a WindowProc event that sets the FLAG_WINDOW_HIDDEN flag to true
+    // If InitWindow is called again, the hidden flag will be interpreted as something the user requested
+    // Save the current flags and restore them after
+    unsigned int savedFlags = CORE.Window.flags;
+
     if (platform.hwnd)
     {
-        int result = DestroyWindow(platform.hwnd);
+        BOOL result = DestroyWindow(platform.hwnd);
-        if (result == 0) TRACELOG(LOG_WARNING, "WIN32: WINDOW: Failed on window destroy [ERROR: %u]", GetLastError());
+        if (!result) TRACELOG(LOG_WARNING, "WIN32: WINDOW: Failed on window destroy [ERROR: %u]", GetLastError());
+
+        HINSTANCE hInstance = GetModuleHandleW(0);
+        result = UnregisterClassW(CLASS_NAME, hInstance);
+        if (!result) TRACELOG(LOG_WARNING, "WIN32: WINDOW: Failed to unregister window class [ERROR: %u]", GetLastError());
+
         platform.hwnd = NULL;
     }
+
+    CORE.Window.flags = savedFlags;
+
+#if SUPPORT_WINMM_HIGHRES_TIMER && !SUPPORT_BUSY_WAIT_LOOP
+    timeEndPeriod(1);           // Restore time period
+#endif
 }
 
 // Window procedure, message processing callback

src/raymath.h

@@ -2381,10 +2381,31 @@ RMAPI Quaternion QuaternionFromVector3ToVector3(Vector3 from, Vector3 to)
     float cos2Theta = (from.x*to.x + from.y*to.y + from.z*to.z); // Vector3DotProduct(from, to)
     Vector3 cross = { from.y*to.z - from.z*to.y, from.z*to.x - from.x*to.z, from.x*to.y - from.y*to.x }; // Vector3CrossProduct(from, to)
 
+    float lengths = sqrtf(cross.x*cross.x + cross.y*cross.y + cross.z*cross.z + cos2Theta*cos2Theta); // |from|*|to|
+
     result.x = cross.x;
     result.y = cross.y;
     result.z = cross.z;
-    result.w = sqrtf(cross.x*cross.x + cross.y*cross.y + cross.z*cross.z + cos2Theta*cos2Theta) + cos2Theta;
+    result.w = lengths + cos2Theta;
+
+    // Opposite vectors: cross product is zero, rotate 180 degrees around any axis perpendicular to 'from'
+    if ((lengths > 0.0f) && (result.w <= lengths*EPSILON))
+    {
+        if (fabsf(from.x) > fabsf(from.z))
+        {
+            result.x = -from.y;
+            result.y = from.x;
+            result.z = 0.0f;
+        }
+        else
+        {
+            result.x = 0.0f;
+            result.y = -from.z;
+            result.z = from.y;
+        }
+
+        result.w = 0.0f;
+    }
 
     // QuaternionNormalize(q);
     // NOTE: Normalize to essentially nlerp the original and identity to 0.5