st/wgl: check if WGL_SWAP_INTERVAL is defined in wglSwapIntervalEXT()

This allows the WGL_SWAP_INTERVAL env var to override any application
calls to wglSwapIntervalEXT().  Useful for debugging, or to set the
interval to zero to effectively disable the swap interval.

Note: we also rename the previous instance of SVGA_SWAP_INTERVAL to
WGL_SWAP_INTERVAL since this is a WGL feature and not related to the
svga driver.

Reviewed-by: Charmaine Lee <[email protected]>

2 files changed, 2 insertions, 2 deletions

diff --git a/src/gallium/state_trackers/wgl/stw_device.c b/src/gallium/state_trackers/wgl/stw_device.c
index b88e1100ebb..e43f12f7f2b 100644
--- a/src/gallium/state_trackers/wgl/stw_device.c
+++ b/src/gallium/state_trackers/wgl/stw_device.c
@@ -135,7 +135,7 @@ stw_init(const struct stw_winsys *stw_winsys)
    stw_pixelformat_init();
 
    /* env var override for WGL_EXT_swap_control, useful for testing/debugging */
-   const char *s = os_get_option("SVGA_SWAP_INTERVAL");
+   const char *s = os_get_option("WGL_SWAP_INTERVAL");
    if (s) {
       stw_dev->swap_interval = atoi(s);
    }
diff --git a/src/gallium/state_trackers/wgl/stw_ext_swapinterval.c b/src/gallium/state_trackers/wgl/stw_ext_swapinterval.c
index b2074a73fb7..3b913e7db93 100644
--- a/src/gallium/state_trackers/wgl/stw_ext_swapinterval.c
+++ b/src/gallium/state_trackers/wgl/stw_ext_swapinterval.c
@@ -48,7 +48,7 @@ wglSwapIntervalEXT(int interval)
       SetLastError(ERROR_INVALID_DATA);
       return FALSE;
    }
-   if (stw_dev) {
+   if (stw_dev && !os_get_option("WGL_SWAP_INTERVAL")) {
       stw_dev->swap_interval = interval;
    }
    return TRUE;