Fix crash on OSX because of pick fbo

Since we use the cache, the fbo wasn't properly unbound after use.

Maybe we should revert to the last currently bound fbo instead of zero.

src/goxel.c

@@ -194,6 +194,7 @@ static void update_pick_fbo(const int view_size[2], const volume_t *volume)
         render_settings_t rend_settings;
         float view_mat[4][4];
         float proj_mat[4][4];
+        int view_size[2];
     } key_t;
 
     key_t key = {0};
@@ -216,6 +217,7 @@ static void update_pick_fbo(const int view_size[2], const volume_t *volume)
         .rend_settings = goxel.rend.settings,
         .view_mat = MAT4_COPY(goxel.rend.view_mat),
         .proj_mat = MAT4_COPY(goxel.rend.proj_mat),
+        .view_size = {view_size[0], view_size[1]},
     };
 
     if (memcmp(&key, &cache_key, sizeof(key_t)) == 0) {
@@ -269,6 +271,7 @@ static bool goxel_unproject_on_volume(
     if (x < 0 || x >= view_size[0] ||
         y < 0 || y >= view_size[1]) return false;
     GL(glReadPixels(x, y, 1, 1, GL_RGBA, GL_UNSIGNED_BYTE, &pixel));
+    GL(glBindFramebuffer(GL_FRAMEBUFFER, 0));
 
     unpack_pos_data(pixel, voxel_pos, &face, &tile_id);
     if (!tile_id) return false;