E:/Eigene Dateien/Eigene Projekte/c0re/TextureAlpha.cpp

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/*
        This file is part of c0re.

        c0re is a multiplayer RTS on a hexagonal map with an evolving unit concept.
    Copyright (C) 2007 Stephan Hofmann

    c0re 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 3 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, see <http://www.gnu.org/licenses/>.
*/

#include "TextureAlpha.h"

#include "system.h"
#include <GL/gl.h>
#include <GL/glu.h>

TextureAlpha::TextureAlpha()
{
        handlerTexture = -1;
}

TextureAlpha::~TextureAlpha()
{

}


int TextureAlpha::render(double x_begin, double x_end, double y_begin, double y_end)
{
        int ret = 0;

        if (handlerTexture != -1)
        {       
                glEnable(GL_BLEND);
                glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
                glBindTexture(GL_TEXTURE_2D, handlerTexture);
                glBegin(GL_QUADS);
                        // top left vertex
                        glTexCoord2d(x_begin, y_begin);
                        glVertex3d(0.5, 0.5, 0.0);
                        // bottom left vertex
                        glTexCoord2d(x_begin, y_end);
                        glVertex3d(0.5, -0.5, 0.0);
                        // bottom right vertex
                        glTexCoord2d(x_end, y_end);
                        glVertex3d(-0.5, -0.5, 0.0);
                        // top right vertex
                        glTexCoord2d(x_end, y_begin);
                        glVertex3d(-0.5, 0.5, 0.0);
                glEnd();

                glDisable(GL_BLEND);
                glBindTexture(GL_TEXTURE_2D, 0);
        }

        return ret;
}

int TextureAlpha::loadAndBind(std::string p_filename, eTextureModification p_modifikationflag)
{
        int ret = 0;
        p_modifikationflag = TM_Masked_Normal;
        TextureData* td = 0;

        td = loadPNG(p_filename);

        //postprozess td -> change RED to Black with Alpha = 0.0
        int j=0,i;
        for (i=0; i < (td->infoheader.biWidth) * (td->infoheader.biHeight); i++)
        {            
                //if red
                if ((td->l_texture[j+0] == 255) && (td->l_texture[j+1] == 0) && (td->l_texture[j+2] == 0))
                {       
                        //adjust to black with alpha = 0
                        td->l_texture[j+0] = 0;
                        td->l_texture[j+3] = 0;
                }
                j += 4; // Go to the next position
        }
        handlerTexture = bind(td);
        ratio = td->infoheader.biWidth / td->infoheader.biHeight;
        //dump the rawdata
        free(td->l_texture);

        return ret;
}

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