/*

 * GStreamer

 * Copyright (C) 2015 Matthew Waters <matthew@centricular.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 "gstglshaderstrings.h"

#define MEDIUMP_PRECISION \

   "#ifdef GL_ES\n" \

   "precision mediump float;\n" \

   "#endif\n"

#define HIGHP_PRECISION \

   "#ifdef GL_ES\n" \

   "precision highp float;\n" \

   "#endif\n"

/* *INDENT-OFF* */

const gchar *gst_gl_shader_string_fragment_mediump_precision = 

    MEDIUMP_PRECISION;

const gchar *gst_gl_shader_string_fragment_highp_precision = 

    HIGHP_PRECISION;

const gchar *gst_gl_shader_string_vertex_default =

    "attribute vec4 a_position;\n"

    "attribute vec2 a_texcoord;\n"

    "varying vec2 v_texcoord;\n"

    "void main()\n"

    "{\n"

    "   gl_Position = a_position;\n"

    "   v_texcoord = a_texcoord;\n"

    "}\n";

const gchar *gst_gl_shader_string_vertex_mat4_texture_transform =

    "uniform mat4 u_transformation;\n"

    "attribute vec4 a_position;\n"

    "attribute vec2 a_texcoord;\n"

    "varying vec2 v_texcoord;\n"

    "void main()\n"

    "{\n"

    "   gl_Position = a_position;\n"

    "   v_texcoord = (u_transformation * vec4(a_texcoord, 0, 1)).xy;\n"

    "}\n";

const gchar *gst_gl_shader_string_vertex_mat4_vertex_transform =

    "uniform mat4 u_transformation;\n"

    "attribute vec4 a_position;\n"

    "attribute vec2 a_texcoord;\n"

    "varying vec2 v_texcoord;\n"

    "void main()\n"

    "{\n"

    "   gl_Position = u_transformation * a_position;\n"

    "   v_texcoord = a_texcoord;\n"

    "}\n";

#define DEFAULT_FRAGMENT_BODY \

    "varying vec2 v_texcoord;\n" \

    "uniform sampler2D tex;\n" \

    "void main()\n" \

    "{\n" \

    "  gl_FragColor = texture2D(tex, v_texcoord);\n" \

    "}"

const gchar *gst_gl_shader_string_fragment_default =

    MEDIUMP_PRECISION

    DEFAULT_FRAGMENT_BODY;

#define EXTERNAL_FRAGMENT_HEADER \

    "#extension GL_OES_EGL_image_external : require\n"

#define EXTERNAL_FRAGMENT_BODY \

    "varying vec2 v_texcoord;\n" \

    "uniform samplerExternalOES tex;\n" \

    "void main()\n" \

    "{\n" \

    "  gl_FragColor = texture2D(tex, v_texcoord);\n" \

    "}"

const gchar *gst_gl_shader_string_fragment_external_oes_default =

    EXTERNAL_FRAGMENT_HEADER

    MEDIUMP_PRECISION

    EXTERNAL_FRAGMENT_BODY;

/* *INDENT-ON* */

/**

 * gst_gl_shader_string_get_highest_precision:

 * @context: a #GstGLContext

 * @version: a #GstGLSLVersion

 * @profile: a #GstGLSLProfile

 *

 * Generates a shader string that defines the precision of float types in

 * GLSL shaders.  This is particularly needed for fragment shaders in a

 * GLSL ES context where there is no default precision specified.

 *

 * Practically, this will return the string 'precision mediump float'

 * or 'precision highp float' depending on if high precision floats are

 * determined to be supported.

 *

 * Returns: a shader string defining the precision of float types based on

 *      @context, @version and @profile

 *

 * Since: 1.16

 */

const gchar *

gst_gl_shader_string_get_highest_precision (GstGLContext * context,

    GstGLSLVersion version, GstGLSLProfile profile)

{

  if (gst_gl_context_supports_precision (context, version, profile)) {

    if (gst_gl_context_supports_precision_highp (context, version, profile))

      return gst_gl_shader_string_fragment_highp_precision;

    else

      return gst_gl_shader_string_fragment_mediump_precision;

  }

  return "";

}

/**

 * gst_gl_shader_string_fragment_get_default:

 * @context: a #GstGLContext

 * @version: a #GstGLSLVersion

 * @profile: a #GstGLSLProfile

 *

 * Returns: a passthrough shader string for copying an input texture to

 *          the output

 *

 * Since: 1.16

 */

gchar *

gst_gl_shader_string_fragment_get_default (GstGLContext * context,

    GstGLSLVersion version, GstGLSLProfile profile)

{

  const gchar *precision =

      gst_gl_shader_string_get_highest_precision (context, version, profile);

  return g_strdup_printf ("%s%s", precision, DEFAULT_FRAGMENT_BODY);

}

/**

 * gst_gl_shader_string_fragment_external_oes_get_default:

 * @context: a #GstGLContext

 * @version: a #GstGLSLVersion

 * @profile: a #GstGLSLProfile

 *

 * Returns: a passthrough shader string for copying an input external-oes

 *          texture to the output

 *

 * Since: 1.16

 */

gchar *

gst_gl_shader_string_fragment_external_oes_get_default (GstGLContext * context,

    GstGLSLVersion version, GstGLSLProfile profile)

{

  const gchar *precision =

      gst_gl_shader_string_get_highest_precision (context, version, profile);

  return g_strdup_printf ("%s%s%s", EXTERNAL_FRAGMENT_HEADER, precision,

      EXTERNAL_FRAGMENT_BODY);

}