eagl: fix handling of surface dimension changes

Detect when the eagl surface changed its dimension (when the user rotates
the device for example) and adapt the egl internals to draw to that,
preventing that ios resizes the image again when drawing.

This is particularly harmful when eagl would scale down a image
to draw and the ios screen would scale it back up because the
surface is now bigger than when the element was configured.

ext/eglgles/gstegladaptation_eagl.m

@@ -56,11 +56,15 @@ struct _GstEaglContext
   EAGLContext *eagl_context;
   GLuint framebuffer;
   GLuint color_renderbuffer;
+  GLuint depth_renderbuffer;
 
   UIView *window;
   UIView *used_window;
 };
 
+static gboolean
+gst_egl_adaptation_update_surface (GstEglAdaptationContext * ctx);
+
 void
 gst_egl_adaptation_init (GstEglAdaptationContext * ctx)
 {
@@ -179,8 +183,13 @@ gst_egl_adaptation_create_surface (GstEglAdaptationContext * ctx)
   __block CAEAGLLayer *eaglLayer = (CAEAGLLayer *)[ctx->eaglctx->window layer];
 
   dispatch_sync(dispatch_get_main_queue(), ^{
-    /* Allocate framebuffer */
+
-    glGenFramebuffers(1, &framebuffer);
+    if (ctx->eaglctx->framebuffer) {
+      framebuffer = ctx->eaglctx->framebuffer;
+    } else {
+      /* Allocate framebuffer */
+      glGenFramebuffers(1, &framebuffer);
+    }
     glBindFramebuffer(GL_FRAMEBUFFER, framebuffer);
  
     /* Allocate color render buffer */
@@ -212,6 +221,9 @@ gst_egl_adaptation_create_surface (GstEglAdaptationContext * ctx)
 
   ctx->eaglctx->framebuffer = framebuffer;
   ctx->eaglctx->color_renderbuffer = colorRenderbuffer;
+  ctx->eaglctx->depth_renderbuffer = colorRenderbuffer;
+  ctx->surface_width = width;
+  ctx->surface_height = height;
   glBindRenderbuffer(GL_RENDERBUFFER, ctx->eaglctx->color_renderbuffer);
 
   return TRUE;
@@ -260,18 +272,18 @@ gboolean
 gst_egl_adaptation_update_surface_dimensions (GstEglAdaptationContext *
     ctx)
 {
-  GLint width;
+  CAEAGLLayer *layer = (CAEAGLLayer *)[ctx->eaglctx->window layer];
-  GLint height;
+  CGSize size = layer.frame.size;
 
-  /* Get renderbuffer width/height */
+  if (size.width != ctx->surface_width || size.height != ctx->surface_height) {
-  glGetRenderbufferParameteriv(GL_RENDERBUFFER, GL_RENDERBUFFER_WIDTH, &width);
+    ctx->surface_width = size.width;
-  glGetRenderbufferParameteriv(GL_RENDERBUFFER, GL_RENDERBUFFER_HEIGHT, &height);
+    ctx->surface_height = size.height;
-
+    GST_INFO_OBJECT (ctx->element, "Got surface of %dx%d pixels",
-  if (width != ctx->surface_width || height != ctx->surface_height) {
+        (gint) size.width, (gint) size.height);
-    ctx->surface_width = width;
+    if (!gst_egl_adaptation_update_surface (ctx)) {
-    ctx->surface_height = height;
+      GST_WARNING_OBJECT (ctx->element, "Failed to update surface "
-    GST_INFO_OBJECT (ctx->element, "Got surface of %dx%d pixels", width,
+          "to new dimensions");
-        height);
+    }
     return TRUE;
   }
 
@@ -302,6 +314,23 @@ gst_egl_adaptation_destroy_surface (GstEglAdaptationContext * ctx)
   }
 }
 
+static gboolean
+gst_egl_adaptation_update_surface (GstEglAdaptationContext * ctx)
+{
+  glBindFramebuffer(GL_FRAMEBUFFER, ctx->eaglctx->framebuffer);
+
+  glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT,
+                              GL_RENDERBUFFER, 0);
+  glDeleteRenderbuffers(1, &ctx->eaglctx->depth_renderbuffer);
+
+  glBindRenderbuffer (GL_RENDERBUFFER, 0);
+  glFramebufferRenderbuffer (GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0,
+      GL_RENDERBUFFER, 0);
+  glDeleteRenderbuffers(1, &ctx->eaglctx->color_renderbuffer);
+
+  return gst_egl_adaptation_create_surface (ctx);
+}
+
 void
 gst_egl_adaptation_destroy_context (GstEglAdaptationContext * ctx)
 {

ext/eglgles/gsteglglessink.c

@@ -204,8 +204,7 @@ static void gst_eglglessink_set_render_rectangle (GstVideoOverlay * overlay,
 /* Utility */
 static gboolean gst_eglglessink_create_window (GstEglGlesSink *
     eglglessink, gint width, gint height);
-static gboolean gst_eglglessink_setup_vbo (GstEglGlesSink * eglglessink,
+static gboolean gst_eglglessink_setup_vbo (GstEglGlesSink * eglglessink);
-    gboolean reset);
 static gboolean
 gst_eglglessink_configure_caps (GstEglGlesSink * eglglessink, GstCaps * caps);
 static GstFlowReturn gst_eglglessink_upload (GstEglGlesSink * sink,
@@ -740,17 +739,17 @@ gst_eglglessink_expose (GstVideoOverlay * overlay)
 }
 
 static gboolean
-gst_eglglessink_setup_vbo (GstEglGlesSink * eglglessink, gboolean reset)
+gst_eglglessink_setup_vbo (GstEglGlesSink * eglglessink)
 {
   gdouble render_width, render_height;
   gdouble texture_width, texture_height;
   gdouble x1, x2, y1, y2;
   gdouble tx1, tx2, ty1, ty2;
 
-  GST_INFO_OBJECT (eglglessink, "VBO setup. have_vbo:%d, should reset %d",
+  GST_INFO_OBJECT (eglglessink, "VBO setup. have_vbo:%d",
-      eglglessink->egl_context->have_vbo, reset);
+      eglglessink->egl_context->have_vbo);
 
-  if (eglglessink->egl_context->have_vbo && reset) {
+  if (eglglessink->egl_context->have_vbo) {
     glDeleteBuffers (1, &eglglessink->egl_context->position_buffer);
     glDeleteBuffers (1, &eglglessink->egl_context->index_buffer);
     eglglessink->egl_context->have_vbo = FALSE;
@@ -929,6 +928,7 @@ gst_eglglessink_setup_vbo (GstEglGlesSink * eglglessink, gboolean reset)
     goto HANDLE_ERROR_LOCKED;
 
   eglglessink->egl_context->have_vbo = TRUE;
+
   GST_DEBUG_OBJECT (eglglessink, "VBO setup done");
 
   return TRUE;
@@ -1673,7 +1673,7 @@ gst_eglglessink_render (GstEglGlesSink * eglglessink)
       glClear (GL_COLOR_BUFFER_BIT);
     }
 
-    if (!gst_eglglessink_setup_vbo (eglglessink, FALSE)) {
+    if (!gst_eglglessink_setup_vbo (eglglessink)) {
       GST_OBJECT_UNLOCK (eglglessink);
       GST_ERROR_OBJECT (eglglessink, "VBO setup failed");
       goto HANDLE_ERROR;