diff --git a/miniwin/sdl3gpu/src/miniwin_d3drmviewport.cpp b/miniwin/sdl3gpu/src/miniwin_d3drmviewport.cpp
index 0d0e4cb4..391ccfd4 100644
--- a/miniwin/sdl3gpu/src/miniwin_d3drmviewport.cpp
+++ b/miniwin/sdl3gpu/src/miniwin_d3drmviewport.cpp
@@ -63,6 +63,14 @@ void D3DRMMatrixInvert(D3DRMMATRIX4D out, const D3DRMMATRIX4D m)
 
 void HMM_Perspective_LH_NO(D3DRMMATRIX4D Result, float FOV, float AspectRatio, float Near, float Far)
 {
+	for (int i = 0; i < 4; i++) {
+		std::fill(
+			Result[i],
+			Result[i]+4,
+			0.f
+		);
+	}
+
 	// See https://www.khronos.org/registry/OpenGL-Refpages/gl2.1/xhtml/gluPerspective.xml
 
 	float Cotangent = 1.0f / SDL_tanf(FOV / 2.0f);