GLView

This feature is supported in mobile applications only.

The GLView component renders OpenGL in an elementary object, which hides Evas GL complexity. For more information, see OpenGL ES.

Figure: GLView gears example

Figure: GLView hierarchy

Adding a GLView Component

Create a GLView component with the elm_glview_add() function.

Evas_Object *glview, *parent;

glview = elm_glview_add(parent);

In this example, the size of the GLView is set to 200x200 pixels.

elm_glview_size_set(glview, 200, 200);

Using the GLView API

You can configure the GLView rendering mode by activating the following rendering modes:

• ELM_GLVIEW_ALPHA: Alpha channel rendering mode
• ELM_GLVIEW_DEPTH: Depth buffer rendering mode
• ELM_GLVIEW_STENCIL: Stencil buffer rendering mode
• ELM_GLVIEW_DIRECT: Direct rendering mode
• ELM_GLVIEW_CLIENT_SIDE_ROTATION: The client handles the GL view rotation if direct rendering is enabled

In the following example, the alpha channel and depth buffer rendering mode are enabled.

elm_glview_mode_set(glview, ELM_GLVIEW_ALPHA | ELM_GLVIEW_DEPTH);

The following example shows how to decide what to do with the GL surface when the GLView component is resized.

elm_glview_resize_policy_set(glview, ELM_GLVIEW_RESIZE_POLICY_RECREATE);

The GL surface is destroyed and recreated to the new size (default function). The resize policy can also be set to ELM_GLVIEW_RESIZE_POLICY_SCALE. In that case, only the image object is scaled, not the underlying GL surface.

The following example shows how to set the GLView rendering policy.

elm_glview_render_policy_set(glview, ELM_GLVIEW_RENDER_POLICY_ALWAYS);

The GLView object is always redrawn during the rendering loop. It can also be set to ELM_GLVIEW_RENDER_POLICY_ON_DEMAND (default function), where the GLView component is redrawn only when it is visible.

Register the callbacks:

elm_glview_init_func_set(glview, _init_gl_cb);
elm_glview_del_func_set(glview, _del_gl_cb);
elm_glview_resize_func_set(glview, _resize_gl_cb);
elm_glview_render_func_set(glview, _draw_gl_cb);

• elm_glview_init_func_set() registers an init callback that is called at the GLView object creation.
• elm_glview_del_func_set() registers a del function that is called when the GLView object is deleted.
• elm_glview_resize_func_set() registers the resize function that is called during the rendering loop when the GLView object is resized.
• elm_glview_render_func_set() registers the render function that is called when the GLView object must be redrawn.

Using GLView Callbacks

The GLView component emits the following signals:

• focused: The Glview component is focused. The event_info parameter points at an object of the type Elm_Focus_Info.
• unfocused: The GLView object is unfocused.

To register a callback:

{
      evas_object_smart_callback_add(glview, "focused", focused_cb, data);
}

// Callback function for the "focused" signal
// This callback is called when the GLView is focused
void focused_cb(void *data, Evas_Object *obj, void  *event_info)
{
      Elm_Focus_Info *fi = event_info;

      dlog_print(DLOG_INFO, LOG_TAG, "GLView is focused\n");
}