/*
 *  gstvaapiwindow_glx.c - VA/GLX window abstraction
 *
 *  Copyright (C) 2010-2011 Splitted-Desktop Systems
 *    Author: Gwenole Beauchesne <gwenole.beauchesne@splitted-desktop.com>
 *  Copyright (C) 2012-2014 Intel Corporation
 *    Author: Gwenole Beauchesne <gwenole.beauchesne@intel.com>
 *
 *  This library is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU Lesser General Public License
 *  as published by the Free Software Foundation; either version 2.1
 *  of the License, or (at your option) any later version.
 *
 *  This library is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 *  Lesser General Public License for more details.
 *
 *  You should have received a copy of the GNU Lesser General Public
 *  License along with this library; if not, write to the Free
 *  Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
 *  Boston, MA 02110-1301 USA
 */

/**
 * SECTION:gstvaapiwindow_glx
 * @short_description: VA/GLX window abstraction
 */

#include "sysdeps.h"
#include "gstvaapiwindow_glx.h"
#include "gstvaapiwindow_x11_priv.h"
#include "gstvaapidisplay_x11.h"
#include "gstvaapidisplay_x11_priv.h"
#include "gstvaapidisplay_glx_priv.h"
#include "gstvaapiutils_x11.h"
#include "gstvaapiutils_glx.h"

#define DEBUG 1
#include "gstvaapidebug.h"

#define GST_VAAPI_WINDOW_GLX_GET_PRIVATE(window) \
    (&GST_VAAPI_WINDOW_GLX(window)->priv)

#define GST_VAAPI_WINDOW_GLX_CLASS(klass) \
    ((GstVaapiWindowGLXClass *)(klass))

#define GST_VAAPI_WINDOW_GLX_GET_CLASS(obj) \
    GST_VAAPI_WINDOW_GLX_CLASS(GST_VAAPI_OBJECT_GET_CLASS(obj))

typedef struct _GstVaapiWindowGLXPrivate        GstVaapiWindowGLXPrivate;
typedef struct _GstVaapiWindowGLXClass          GstVaapiWindowGLXClass;

struct _GstVaapiWindowGLXPrivate {
    Colormap            cmap;
    GLContextState     *gl_context;
};

/**
 * GstVaapiWindowGLX:
 *
 * An X11 #Window suitable for GLX rendering.
 */
struct _GstVaapiWindowGLX {
    /*< private >*/
    GstVaapiWindowX11 parent_instance;

    GstVaapiWindowGLXPrivate priv;
};

/**
 * GstVaapiWindowGLXClass:
 *
 * An X11 #Window suitable for GLX rendering.
 */
struct _GstVaapiWindowGLXClass {
    /*< private >*/
    GstVaapiWindowX11Class      parent_class;

    GstVaapiObjectFinalizeFunc  parent_finalize;
    GstVaapiWindowResizeFunc    parent_resize;
};

/* Fill rectangle coords with capped bounds */
static inline void
fill_rect(
    GstVaapiRectangle       *dst_rect,
    const GstVaapiRectangle *src_rect,
    guint                    width,
    guint                    height
)
{
    if (src_rect) {
        dst_rect->x = src_rect->x > 0 ? src_rect->x : 0;
        dst_rect->y = src_rect->y > 0 ? src_rect->y : 0;
        if (src_rect->x + src_rect->width < width)
            dst_rect->width = src_rect->width;
        else
            dst_rect->width = width - dst_rect->x;
        if (src_rect->y + src_rect->height < height)
            dst_rect->height = src_rect->height;
        else
            dst_rect->height = height - dst_rect->y;
    }
    else {
        dst_rect->x      = 0;
        dst_rect->y      = 0;
        dst_rect->width  = width;
        dst_rect->height = height;
    }
}

static void
_gst_vaapi_window_glx_destroy_context(GstVaapiWindow *window)
{
    GstVaapiWindowGLXPrivate * const priv =
        GST_VAAPI_WINDOW_GLX_GET_PRIVATE(window);

    GST_VAAPI_OBJECT_LOCK_DISPLAY(window);
    if (priv->gl_context) {
        gl_destroy_context(priv->gl_context);
        priv->gl_context = NULL;
    }
    GST_VAAPI_OBJECT_UNLOCK_DISPLAY(window);
}

static gboolean
_gst_vaapi_window_glx_create_context(
    GstVaapiWindow     *window,
    GLXContext          foreign_context
)
{
    GstVaapiWindowGLXPrivate * const priv =
        GST_VAAPI_WINDOW_GLX_GET_PRIVATE(window);
    Display * const                  dpy  = GST_VAAPI_OBJECT_XDISPLAY(window);
    GLContextState                   parent_cs;

    parent_cs.display = dpy;
    parent_cs.window  = None;
    parent_cs.context = foreign_context;

    GST_VAAPI_OBJECT_LOCK_DISPLAY(window);
    priv->gl_context = gl_create_context(
        dpy,
        GST_VAAPI_OBJECT_XSCREEN(window),
        &parent_cs
    );
    if (!priv->gl_context) {
        GST_DEBUG("could not create GLX context");
        goto end;
    }

    if (!glXIsDirect(dpy, priv->gl_context->context)) {
        GST_DEBUG("could not create a direct-rendering GLX context");
        goto out_destroy_context;
    }
    goto end;

out_destroy_context:
    gl_destroy_context(priv->gl_context);
    priv->gl_context = NULL;
end:
    GST_VAAPI_OBJECT_UNLOCK_DISPLAY(window);
    return priv->gl_context != NULL;
}

static gboolean
_gst_vaapi_window_glx_ensure_context(
    GstVaapiWindow     *window,
    GLXContext          foreign_context
)
{
    GstVaapiWindowGLXPrivate * const priv =
        GST_VAAPI_WINDOW_GLX_GET_PRIVATE(window);

    if (priv->gl_context) {
        if (!foreign_context || foreign_context == priv->gl_context->context)
            return TRUE;
        _gst_vaapi_window_glx_destroy_context(window);
    }
    return _gst_vaapi_window_glx_create_context(window, foreign_context);
}

static gboolean
gst_vaapi_window_glx_ensure_context(
    GstVaapiWindow     *window,
    GLXContext          foreign_context
)
{
    GstVaapiWindowGLXPrivate * const priv =
        GST_VAAPI_WINDOW_GLX_GET_PRIVATE(window);
    GLContextState old_cs;
    guint width, height;

    if (!_gst_vaapi_window_glx_ensure_context(window, foreign_context))
        return FALSE;

    priv->gl_context->window = GST_VAAPI_OBJECT_ID(window);
    if (!gl_set_current_context(priv->gl_context, &old_cs)) {
        GST_DEBUG("could not make newly created GLX context current");
        return FALSE;
    }

    glDisable(GL_DEPTH_TEST);
    glDepthMask(GL_FALSE);
    glDisable(GL_CULL_FACE);
    glDrawBuffer(GL_BACK);
    glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);
    glEnable(GL_BLEND);
    glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);

    gst_vaapi_window_get_size(window, &width, &height);
    gl_resize(width, height);

    gl_set_bgcolor(0);
    glClear(GL_COLOR_BUFFER_BIT);
    gl_set_current_context(&old_cs, NULL);
    return TRUE;
}

static Visual *
gst_vaapi_window_glx_get_visual(GstVaapiWindow *window)
{
    GstVaapiWindowGLXPrivate * const priv =
        GST_VAAPI_WINDOW_GLX_GET_PRIVATE(window);

    if (!_gst_vaapi_window_glx_ensure_context(window, NULL))
        return NULL;
    return priv->gl_context->visual->visual;
}

static void
gst_vaapi_window_glx_destroy_colormap(GstVaapiWindow *window)
{
    GstVaapiWindowGLXPrivate * const priv =
        GST_VAAPI_WINDOW_GLX_GET_PRIVATE(window);
    Display * const                  dpy  = GST_VAAPI_OBJECT_XDISPLAY(window);

    if (priv->cmap) {
        if (!window->use_foreign_window) {
            GST_VAAPI_OBJECT_LOCK_DISPLAY(window);
            XFreeColormap(dpy, priv->cmap);
            GST_VAAPI_OBJECT_UNLOCK_DISPLAY(window);
        }
        priv->cmap = None;
    }
}

static Colormap
gst_vaapi_window_glx_create_colormap(GstVaapiWindow *window)
{
    GstVaapiWindowGLXPrivate * const priv =
        GST_VAAPI_WINDOW_GLX_GET_PRIVATE(window);
    Display * const                  dpy  = GST_VAAPI_OBJECT_XDISPLAY(window);
    int                              screen;
    XWindowAttributes                wattr;
    gboolean                         success = FALSE;

    if (!priv->cmap) {
        if (!window->use_foreign_window) {
            if (!_gst_vaapi_window_glx_ensure_context(window, NULL))
                return None;
            GST_VAAPI_OBJECT_LOCK_DISPLAY(window);
            x11_trap_errors();
            /* XXX: add a GstVaapiDisplayX11:x11-screen property? */
            screen     = GST_VAAPI_OBJECT_XSCREEN(window);
            priv->cmap = XCreateColormap(
                dpy,
                RootWindow(dpy, screen),
                priv->gl_context->visual->visual,
                AllocNone
            );
            success = x11_untrap_errors() == 0;
            GST_VAAPI_OBJECT_UNLOCK_DISPLAY(window);
        }
        else {
            GST_VAAPI_OBJECT_LOCK_DISPLAY(window);
            x11_trap_errors();
            XGetWindowAttributes(dpy, GST_VAAPI_OBJECT_ID(window), &wattr);
            priv->cmap = wattr.colormap;
            success = x11_untrap_errors() == 0;
            GST_VAAPI_OBJECT_UNLOCK_DISPLAY(window);
        }
        if (!success)
            return None;
    }
    return priv->cmap;
}

static Colormap
gst_vaapi_window_glx_get_colormap(GstVaapiWindow *window)
{
    return gst_vaapi_window_glx_create_colormap(window);
}

static gboolean
gst_vaapi_window_glx_resize(GstVaapiWindow *window,
    guint width, guint height)
{
    GstVaapiWindowGLXPrivate * const priv =
        GST_VAAPI_WINDOW_GLX_GET_PRIVATE(window);
    const GstVaapiWindowGLXClass * const klass =
        GST_VAAPI_WINDOW_GLX_GET_CLASS(window);
    Display * const                  dpy  = GST_VAAPI_OBJECT_XDISPLAY(window);
    GLContextState                   old_cs;

    if (!klass->parent_resize(window, width, height))
        return FALSE;

    GST_VAAPI_OBJECT_LOCK_DISPLAY(window);
    XSync(dpy, False); /* make sure resize completed */
    if (gl_set_current_context(priv->gl_context, &old_cs)) {
        gl_resize(width, height);
        gl_set_current_context(&old_cs, NULL);
    }
    GST_VAAPI_OBJECT_UNLOCK_DISPLAY(window);
    return TRUE;
}

static void
gst_vaapi_window_glx_finalize(GstVaapiWindowGLX *window)
{
    GstVaapiWindow * const base_window = GST_VAAPI_WINDOW(window);

    _gst_vaapi_window_glx_destroy_context(base_window);
    gst_vaapi_window_glx_destroy_colormap(base_window);

    GST_VAAPI_WINDOW_GLX_GET_CLASS(window)->parent_finalize(
        GST_VAAPI_OBJECT(window));
}

static void
gst_vaapi_window_glx_class_init(GstVaapiWindowGLXClass *klass)
{
    GstVaapiWindowClass * const window_class =
        GST_VAAPI_WINDOW_CLASS(klass);
    GstVaapiWindowX11Class * const xwindow_class =
        GST_VAAPI_WINDOW_X11_CLASS(klass);

    gst_vaapi_window_x11_class_init(xwindow_class);
    klass->parent_resize        = window_class->resize;
    klass->parent_finalize      = GST_VAAPI_OBJECT_CLASS(klass)->finalize;
    window_class->resize        = gst_vaapi_window_glx_resize;
    xwindow_class->get_visual   = gst_vaapi_window_glx_get_visual;
    xwindow_class->get_colormap = gst_vaapi_window_glx_get_colormap;
}

GST_VAAPI_OBJECT_DEFINE_CLASS_WITH_CODE(
    GstVaapiWindowGLX,
    gst_vaapi_window_glx,
    gst_vaapi_window_glx_class_init(&g_class))

/**
 * gst_vaapi_window_glx_new:
 * @display: a #GstVaapiDisplay
 * @width: the requested window width, in pixels
 * @height: the requested windo height, in pixels
 *
 * Creates a window with the specified @width and @height. The window
 * will be attached to the @display and remains invisible to the user
 * until gst_vaapi_window_show() is called.
 *
 * Return value: the newly allocated #GstVaapiWindow object
 */
GstVaapiWindow *
gst_vaapi_window_glx_new(GstVaapiDisplay *display, guint width, guint height)
{
    GstVaapiWindow *window;

    g_return_val_if_fail(GST_VAAPI_IS_DISPLAY_GLX(display), NULL);

    window = gst_vaapi_window_new(GST_VAAPI_WINDOW_CLASS(
            gst_vaapi_window_glx_class()), display, width, height);
    if (!window)
        return NULL;

    if (!gst_vaapi_window_glx_ensure_context(window, NULL))
        goto error;
    return window;

error:
    gst_vaapi_window_unref(window);
    return NULL;
}

/**
 * gst_vaapi_window_glx_new_with_xid:
 * @display: a #GstVaapiDisplay
 * @xid: an X11 #Window id
 *
 * Creates a #GstVaapiWindow using the X11 #Window @xid. The caller
 * still owns the window and must call XDestroyWindow() when all
 * #GstVaapiWindow references are released. Doing so too early can
 * yield undefined behaviour.
 *
 * Return value: the newly allocated #GstVaapiWindow object
 */
GstVaapiWindow *
gst_vaapi_window_glx_new_with_xid(GstVaapiDisplay *display, Window xid)
{
    GstVaapiWindow *window;

    GST_DEBUG("new window from xid 0x%08x", (guint)xid);

    g_return_val_if_fail(GST_VAAPI_IS_DISPLAY_GLX(display), NULL);
    g_return_val_if_fail(xid != None, NULL);

    window = gst_vaapi_window_new_from_native(GST_VAAPI_WINDOW_CLASS(
            gst_vaapi_window_glx_class()), display, GINT_TO_POINTER(xid));
    if (!window)
        return NULL;

    if (!gst_vaapi_window_glx_ensure_context(window, NULL))
        goto error;
    return window;

error:
    gst_vaapi_window_unref(window);
    return NULL;
}

/**
 * gst_vaapi_window_glx_get_context:
 * @window: a #GstVaapiWindowGLX
 *
 * Returns the #GLXContext bound to the @window.
 *
 * Return value: the #GLXContext bound to the @window
 */
GLXContext
gst_vaapi_window_glx_get_context(GstVaapiWindowGLX *window)
{
    g_return_val_if_fail(window != NULL, NULL);

    return GST_VAAPI_WINDOW_GLX_GET_PRIVATE(window)->gl_context->context;
}

/**
 * gst_vaapi_window_glx_set_context:
 * @window: a #GstVaapiWindowGLX
 * @ctx: a GLX context
 *
 * Binds GLX context @ctx to @window. If @ctx is non %NULL, the caller
 * is responsible to making sure it has compatible visual with that of
 * the underlying X window. If @ctx is %NULL, a new context is created
 * and the @window owns it.
 *
 * Return value: %TRUE on success
 */
gboolean
gst_vaapi_window_glx_set_context(GstVaapiWindowGLX *window, GLXContext ctx)
{
    g_return_val_if_fail(window != NULL, FALSE);

    return gst_vaapi_window_glx_ensure_context(GST_VAAPI_WINDOW(window), ctx);
}

/**
 * gst_vaapi_window_glx_make_current:
 * @window: a #GstVaapiWindowGLX
 *
 * Makes the @window GLX context the current GLX rendering context of
 * the calling thread, replacing the previously current context if
 * there was one.
 *
 * Return value: %TRUE on success
 */
gboolean
gst_vaapi_window_glx_make_current(GstVaapiWindowGLX *window)
{
    gboolean success;

    g_return_val_if_fail(window != NULL, FALSE);

    GST_VAAPI_OBJECT_LOCK_DISPLAY(window);
    success = gl_set_current_context(window->priv.gl_context, NULL);
    GST_VAAPI_OBJECT_UNLOCK_DISPLAY(window);
    return success;
}

/**
 * gst_vaapi_window_glx_swap_buffers:
 * @window: a #GstVaapiWindowGLX
 *
 * Promotes the contents of the back buffer of @window to become the
 * contents of the front buffer of @window. This simply is wrapper
 * around glXSwapBuffers().
 */
void
gst_vaapi_window_glx_swap_buffers(GstVaapiWindowGLX *window)
{
    g_return_if_fail(window != NULL);

    GST_VAAPI_OBJECT_LOCK_DISPLAY(window);
    gl_swap_buffers(window->priv.gl_context);
    GST_VAAPI_OBJECT_UNLOCK_DISPLAY(window);
}

/**
 * gst_vaapi_window_glx_put_texture:
 * @window: a #GstVaapiWindowGLX
 * @texture: a #GstVaapiTexture
 * @src_rect: the sub-rectangle of the source texture to
 *   extract and process. If %NULL, the entire texture will be used.
 * @dst_rect: the sub-rectangle of the destination
 *   window into which the texture is rendered. If %NULL, the entire
 *   window will be used.
 *
 * Renders the @texture region specified by @src_rect into the @window
 * region specified by @dst_rect.
 *
 * NOTE: only GL_TEXTURE_2D textures are supported at this time.
 *
 * Return value: %TRUE on success
 */
gboolean
gst_vaapi_window_glx_put_texture(
    GstVaapiWindowGLX       *window,
    GstVaapiTexture         *texture,
    const GstVaapiRectangle *src_rect,
    const GstVaapiRectangle *dst_rect
)
{
    GstVaapiRectangle tmp_src_rect, tmp_dst_rect;
    GLTextureState ts;
    GLenum tex_target;
    GLuint tex_id;
    guint tex_width, tex_height;
    guint win_width, win_height;

    g_return_val_if_fail(window != NULL, FALSE);
    g_return_val_if_fail(texture != NULL, FALSE);

    gst_vaapi_texture_get_size(texture, &tex_width, &tex_height);
    fill_rect(&tmp_src_rect, src_rect, tex_width, tex_height);
    src_rect = &tmp_src_rect;

    gst_vaapi_window_get_size(GST_VAAPI_WINDOW(window), &win_width, &win_height);
    fill_rect(&tmp_dst_rect, dst_rect, win_width, win_height);
    dst_rect = &tmp_dst_rect;

    /* XXX: only GL_TEXTURE_2D textures are supported at this time */
    tex_target = gst_vaapi_texture_get_target(texture);
    if (tex_target != GL_TEXTURE_2D)
        return FALSE;

    tex_id = gst_vaapi_texture_get_id(texture);
    if (!gl_bind_texture(&ts, tex_target, tex_id))
        return FALSE;
    glColor4f(1.0f, 1.0f, 1.0f, 1.0f);
    glPushMatrix();
    glTranslatef((GLfloat)dst_rect->x, (GLfloat)dst_rect->y, 0.0f);
    glBegin(GL_QUADS);
    {
        const float tx1 = (float)src_rect->x / tex_width;
        const float tx2 = (float)(src_rect->x + src_rect->width) / tex_width;
        const float ty1 = (float)src_rect->y / tex_height;
        const float ty2 = (float)(src_rect->y + src_rect->height) / tex_height;
        const guint w   = dst_rect->width;
        const guint h   = dst_rect->height;
        glTexCoord2f(tx1, ty1); glVertex2i(0, 0);
        glTexCoord2f(tx1, ty2); glVertex2i(0, h);
        glTexCoord2f(tx2, ty2); glVertex2i(w, h);
        glTexCoord2f(tx2, ty1); glVertex2i(w, 0);
    }
    glEnd();
    glPopMatrix();
    gl_unbind_texture(&ts);
    return TRUE;
}