/*
 * This program source code file is part of KiCad, a free EDA CAD application.
 *
 * Copyright (C) 2015 Mario Luzeiro <mrluzeiro@ua.pt>
 * Copyright (C) 1992-2015 KiCad Developers, see AUTHORS.txt for contributors.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, you may find one here:
 * http://www.gnu.org/licenses/old-licenses/gpl-2.0.html
 * or you may search the http://www.gnu.org website for the version 2 license,
 * or you may write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA
 */

/**
 * @file  ogl_utils.cpp
 * @brief implements generic openGL functions that are common to any openGL target
 */


#include "openGL_includes.h"
#include "ogl_utils.h"

void OGL_GetScreenshot( wxImage &aDstImage )
{
    struct viewport_params
    {
        GLint originX;
        GLint originY;
        GLint x;
        GLint y;
    } viewport;

    glGetIntegerv( GL_VIEWPORT, (GLint*) &viewport );

    unsigned char* pixelbuffer = (unsigned char*) malloc( viewport.x * viewport.y * 3 );
    unsigned char* alphabuffer = (unsigned char*) malloc( viewport.x * viewport.y );

    glPixelStorei( GL_PACK_ALIGNMENT, 1 );
    glReadBuffer( GL_BACK_LEFT );

    glReadPixels( viewport.originX, viewport.originY,
                  viewport.x, viewport.y,
                  GL_RGB, GL_UNSIGNED_BYTE, pixelbuffer );

    glReadPixels( viewport.originX, viewport.originY,
                  viewport.x, viewport.y,
                  GL_ALPHA, GL_UNSIGNED_BYTE, alphabuffer );

    // "Sets the image data without performing checks.
    //  The data given must have the size (width*height*3)
    //  The data must have been allocated with malloc()
    //  If static_data is false, after this call the pointer to the data is owned
    //  by the wxImage object, that will be responsible for deleting it."
    aDstImage.SetData( pixelbuffer, viewport.x, viewport.y, false );
    aDstImage.SetAlpha( alphabuffer, false );

    aDstImage = aDstImage.Mirror( false );
}


GLuint OGL_LoadTexture( const CIMAGE &aImage )
{
    unsigned char* rgbaBuffer = (unsigned char*) malloc( aImage.GetWidth() * aImage.GetHeight() * 4 );

    unsigned char* dst = rgbaBuffer;
    unsigned char* ori = aImage.GetBuffer();
    for( unsigned int i = 0; i < (aImage.GetWidth() * aImage.GetHeight()); ++i )
    {
        unsigned char v = *ori;
        ori++;

        dst[0] = v;
        dst[1] = v;
        dst[2] = v;
        dst[3] = v;
        dst+= 4;
    }

    GLuint texture;
    glPixelStorei (GL_UNPACK_ALIGNMENT, 4);
    glPixelStorei (GL_PACK_ALIGNMENT, 4);

    glGenTextures( 1, &texture );
    glBindTexture( GL_TEXTURE_2D, texture );

    //gluBuild2DMipmaps( GL_TEXTURE_2D, GL_RGBA, aImage.GetWidth(), aImage.GetHeight(), GL_RGBA, GL_UNSIGNED_BYTE, rgbaBuffer );

    glTexImage2D( GL_TEXTURE_2D, 0, GL_RGBA, aImage.GetWidth(), aImage.GetHeight(), 0, GL_RGBA, GL_UNSIGNED_BYTE, rgbaBuffer );

    //glTexParameterf( GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR );
    glTexParameterf( GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR );
    glTexParameterf( GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR );
    glTexParameterf( GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
    glTexParameterf( GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);

    glTexEnvf( GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE );

    glBindTexture( GL_TEXTURE_2D, 0 );

    free( rgbaBuffer );

    return texture;
}


void OGL_SetMaterial( const SMATERIAL & aMaterial )
{
    const SFVEC4F ambient  = SFVEC4F( aMaterial.m_Ambient,  1.0f );
    const SFVEC4F diffuse  = SFVEC4F( aMaterial.m_Diffuse - aMaterial.m_Transparency,  1.0f );
    const SFVEC4F specular = SFVEC4F( aMaterial.m_Specular, 1.0f );
    const SFVEC4F emissive = SFVEC4F( aMaterial.m_Emissive, 1.0f );

    glMaterialfv( GL_FRONT_AND_BACK, GL_AMBIENT,  &ambient.r );
    glMaterialfv( GL_FRONT_AND_BACK, GL_DIFFUSE,  &diffuse.r );
    glMaterialfv( GL_FRONT_AND_BACK, GL_SPECULAR, &specular.r );
    glMaterialfv( GL_FRONT_AND_BACK, GL_EMISSION, &emissive.r );
    glMaterialf(  GL_FRONT_AND_BACK, GL_SHININESS, 128.0f * ((aMaterial.m_Shininess > 1.0f)?1.0f:aMaterial.m_Shininess) );
}