/*
 * GStreamer
 * Copyright (C) 2008 Filippo Argiolas <filippo.argiolas@gmail.com>
 * Copyright (C) 2015 Michał Dębski <debski.mi.zd@gmail.com>
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License as published by the Free Software Foundation; either
 * version 2 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
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public
 * License along with this library; if not, write to the
 * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
 * Boston, MA 02110-1301, USA.
 */

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include "../gstgleffects.h"

static float *
gst_gl_effects_blur_kernel (void)
{
  /* gaussian kernel (well, actually vector), size 9, standard
   * deviation 3.0 */
  /* FIXME: make this a runtime property */
  static gfloat *kernel = NULL;
  if (G_UNLIKELY (NULL == kernel)) {
    /* 3x3 matrix */
    kernel = g_malloc (sizeof (gfloat) * 9);
    fill_gaussian_kernel (kernel, 7, 3.f);
  }
  return kernel;
}

static void
gst_gl_effects_blur_callback_hconv (gint width, gint height, guint texture,
    gpointer data)
{
  GstGLShader *shader = NULL;
  GstGLEffects *effects = GST_GL_EFFECTS (data);

  if (NULL != (shader = gst_gl_effects_get_fragment_shader (effects, "hconv0",
              hconv7_fragment_source_gles2))) {
    GstGLFilter *filter = GST_GL_FILTER (effects);
    GstGLFuncs *gl = GST_GL_BASE_FILTER (filter)->context->gl_vtable;

#if GST_GL_HAVE_OPENGL
    if (USING_OPENGL (GST_GL_BASE_FILTER (filter)->context)) {
      gl->MatrixMode (GL_PROJECTION);
      gl->LoadIdentity ();
    }
#endif

    gst_gl_shader_use (shader);

    gl->ActiveTexture (GL_TEXTURE0);
    gl->BindTexture (GL_TEXTURE_2D, texture);

    gst_gl_shader_set_uniform_1i (shader, "tex", 0);
    gst_gl_shader_set_uniform_1f (shader, "gauss_width", width);
    gst_gl_shader_set_uniform_1fv (shader, "kernel", 7,
        gst_gl_effects_blur_kernel ());

    gst_gl_filter_draw_texture (filter, texture, width, height);
  }
}

static void
gst_gl_effects_blur_callback_vconv (gint width, gint height, guint texture,
    gpointer data)
{
  GstGLShader *shader = NULL;
  GstGLEffects *effects = GST_GL_EFFECTS (data);
  GstGLFilter *filter = GST_GL_FILTER (effects);

  if (NULL != (shader = gst_gl_effects_get_fragment_shader (effects, "vconv0",
              vconv7_fragment_source_gles2))) {
    GstGLFuncs *gl = GST_GL_BASE_FILTER (filter)->context->gl_vtable;

#if GST_GL_HAVE_OPENGL
    if (USING_OPENGL (GST_GL_BASE_FILTER (filter)->context)) {
      gl->MatrixMode (GL_PROJECTION);
      gl->LoadIdentity ();
    }
#endif

    gst_gl_shader_use (shader);

    gl->ActiveTexture (GL_TEXTURE0);
    gl->BindTexture (GL_TEXTURE_2D, texture);

    gst_gl_shader_set_uniform_1i (shader, "tex", 0);
    gst_gl_shader_set_uniform_1f (shader, "gauss_height", height);
    gst_gl_shader_set_uniform_1fv (shader, "kernel", 7,
        gst_gl_effects_blur_kernel ());

    gst_gl_filter_draw_texture (filter, texture, width, height);
  }
}

void
gst_gl_effects_blur (GstGLEffects * effects)
{
  GstGLFilter *filter = GST_GL_FILTER (effects);

  gst_gl_filter_render_to_target (filter, TRUE, effects->intexture,
      effects->midtexture[0], gst_gl_effects_blur_callback_hconv, effects);
  gst_gl_filter_render_to_target (filter, FALSE, effects->midtexture[0],
      effects->outtexture, gst_gl_effects_blur_callback_vconv, effects);
}