gl: Don't query the display when checking if the context changed

If display has changed, the associated context must change. A
context is tied a display so we can avoid this check, eliminating
unnecessary work during context acquisition and release.

2 files changed, 8 insertions, 18 deletions

diff --git a/src/cairo-egl-context.c b/src/cairo-egl-context.c
index 12924cc8..ba8f60f1 100644
--- a/src/cairo-egl-context.c
+++ b/src/cairo-egl-context.c
@@ -50,7 +50,6 @@ typedef struct _cairo_egl_context {
 
     EGLSurface dummy_surface;
 
-    EGLDisplay previous_display;
     EGLContext previous_context;
     EGLSurface previous_surface;
 } cairo_egl_context_t;
@@ -66,9 +65,8 @@ static cairo_bool_t
 _context_acquisition_changed_egl_state (cairo_egl_context_t *ctx,
 					EGLSurface current_surface)
 {
-    return !(ctx->previous_display == ctx->display &&
-	     ctx->previous_surface == current_surface &&
-	     ctx->previous_context == ctx->context);
+    return ctx->previous_context != ctx->context ||
+	   ctx->previous_surface != current_surface;
 }
 
 static EGLSurface
@@ -85,18 +83,15 @@ _egl_get_current_surface (cairo_egl_context_t *ctx)
 static void
 _egl_query_current_state (cairo_egl_context_t *ctx)
 {
-    ctx->previous_display = eglGetCurrentDisplay ();
     ctx->previous_surface = eglGetCurrentSurface (EGL_DRAW);
     ctx->previous_context = eglGetCurrentContext ();
 
     /* If any of the values were none, assume they are all none. Not all
        drivers seem well behaved when it comes to using these values across
        multiple threads. */
-    if (ctx->previous_surface == EGL_NO_SURFACE
-	|| ctx->previous_display == EGL_NO_DISPLAY
-	|| ctx->previous_context == EGL_NO_CONTEXT) {
+    if (ctx->previous_surface == EGL_NO_SURFACE ||
+	ctx->previous_context == EGL_NO_CONTEXT) {
 	ctx->previous_surface = EGL_NO_SURFACE;
-	ctx->previous_display = EGL_NO_DISPLAY;
 	ctx->previous_context = EGL_NO_CONTEXT;
     }
 }
diff --git a/src/cairo-glx-context.c b/src/cairo-glx-context.c
index ebe53608..3761b907 100644
--- a/src/cairo-glx-context.c
+++ b/src/cairo-glx-context.c
@@ -53,7 +53,6 @@ typedef struct _cairo_glx_context {
     Window dummy_window;
     GLXContext context;
 
-    Display *previous_display;
     GLXDrawable previous_drawable;
     GLXContext previous_context;
 
@@ -70,9 +69,8 @@ static cairo_bool_t
 _context_acquisition_changed_glx_state (cairo_glx_context_t *ctx,
 					GLXDrawable current_drawable)
 {
-    return !(ctx->previous_display == ctx->display &&
-	     ctx->previous_drawable == current_drawable &&
-	     ctx->previous_context == ctx->context);
+    return ctx->previous_drawable != current_drawable ||
+	   ctx->previous_context != ctx->context;
 }
 
 static GLXDrawable
@@ -90,17 +88,14 @@ static void
 _glx_query_current_state (cairo_glx_context_t * ctx)
 {
     ctx->previous_drawable = glXGetCurrentDrawable ();
-    ctx->previous_display = glXGetCurrentDisplay ();
     ctx->previous_context = glXGetCurrentContext ();
 
     /* If any of the values were none, assume they are all none. Not all
        drivers seem well behaved when it comes to using these values across
        multiple threads. */
-    if (ctx->previous_drawable == None
-	|| ctx->previous_display == None
-	|| ctx->previous_context == None) {
+    if (ctx->previous_drawable == None ||
+	ctx->previous_context == None) {
 	ctx->previous_drawable = None;
-	ctx->previous_display = None;
 	ctx->previous_context = None;
     }
 }