diff --git a/src/render/SDL_render.c b/src/render/SDL_render.c
index cf80cfb8c..d5030fea8 100644
--- a/src/render/SDL_render.c
+++ b/src/render/SDL_render.c
@@ -33,12 +33,14 @@
 #define SDL_WINDOWRENDERDATA    "_SDL_WindowRenderData"
 
 #define CHECK_RENDERER_MAGIC(renderer, retval) \
+    SDL_assert(renderer && renderer->magic == &renderer_magic); \
     if (!renderer || renderer->magic != &renderer_magic) { \
         SDL_SetError("Invalid renderer"); \
         return retval; \
     }
 
 #define CHECK_TEXTURE_MAGIC(texture, retval) \
+    SDL_assert(texture && texture->magic == &texture_magic); \
     if (!texture || texture->magic != &texture_magic) { \
         SDL_SetError("Invalid texture"); \
         return retval; \
diff --git a/src/video/SDL_video.c b/src/video/SDL_video.c
index 2f15ec528..8f7834c0f 100644
--- a/src/video/SDL_video.c
+++ b/src/video/SDL_video.c
@@ -130,6 +130,7 @@ static SDL_VideoDevice *_this = NULL;
         SDL_UninitializedVideo(); \
         return retval; \
     } \
+    SDL_assert(window && window->magic == &_this->window_magic); \
     if (!window || window->magic != &_this->window_magic) { \
         SDL_SetError("Invalid window"); \
         return retval; \
@@ -141,6 +142,7 @@ static SDL_VideoDevice *_this = NULL;
         return retval; \
     } \
     SDL_assert(_this->displays != NULL); \
+    SDL_assert(displayIndex >= 0 && displayIndex < _this->num_displays); \
     if (displayIndex < 0 || displayIndex >= _this->num_displays) { \
         SDL_SetError("displayIndex must be in the range 0 - %d", \
                      _this->num_displays - 1); \