ExampleRenderingContext.cpp

Example for drawing on the GPU Using the OpenGLFramwork

,glfBatch,glfScreen,glfVertexBuffer,glfElementBuffer

Author

MIP

/*
 This file is part of the BIAS library (Basic ImageAlgorithmS).

 Copyright (C) 2003-2009    (see file CONTACT for details)
 Multimediale Systeme der Informationsverarbeitung
 Institut fuer Informatik
 Christian-Albrechts-Universitaet Kiel


 BIAS 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.

 BIAS 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 BIAS; if not, write to the Free Software
 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

/**
   @example ExampleRenderingContext.cpp
   @relates glfPBuffer,glfBatch,glfScreen,glfVertexBuffer,glfElementBuffer
   @brief Example for drawing on the GPU Using the OpenGLFramwork
   @ingroup g_examples
   @ingroup g_openglframework
   @author MIP
*/


#include <Base/Image/ImageIO.hh>
#include <OpenGLFramework/RenderingContext/glfPBuffer.hh>
#include <OpenGLFramework/Base/glfException.hh>
#include <OpenGLFramework/Base/glfBatch.hh>
#include <OpenGLFramework/Base/glfScreen.hh>
#include <OpenGLFramework/Base/glfViewport.hh>
#include <OpenGLFramework/Base/glfVertexBuffer.hh>
#include <OpenGLFramework/Base/glfElementBuffer.hh>

#include <vector>

using namespace std;
using namespace BIAS;

/** \cond HIDDEN_SYMBOLS */
// vertex structure
struct Vertex {

  Vertex(float x, float y, float z, unsigned char r, unsigned char g, unsigned char b) {
    position[0] = x;
    position[1] = y;
    position[2] = z;
    color[0] = r;
    color[1] = g;
    color[2] = b;
    color[3] = 255;
  }

  float position[3];
  unsigned char color[4];
};
/** \endcond */

int main(int argc, char* argv[])
{
  // only need glfRenderingContext interface.
  glfPBuffer pbuffer;
  glfRenderingContext* context = &pbuffer;

  try {

    // fill configuration
    glfRenderingContextConfig cfg;
    cfg.width         = 640;
    cfg.height        = 480;
    cfg.doubleBuffer  = 0;
    cfg.redSize       = 8;
    cfg.greenSize     = 8;
    cfg.blueSize      = 8;
    cfg.alphaSize     = 0;
    cfg.depthSize     = 16;
    cfg.stencilSize   = 0;

    // initialize context
    context->Init(cfg);

    // get real configuration
    glfRenderingContextConfig realCfg;
    context->GetConfig(realCfg);

    // print config
    cout << "--- Requested Config ---" << endl;
    cfg.Dump(cout);
    cout << endl << "--- Real Config ---" << endl;
    realCfg.Dump(cout);

    // clear screen
    glfScreen& screen = glfScreen::GetInstance();
    screen.ClearColorBuffer(1.0f, 0.5f, 0.0f, 0.0f);
    screen.ClearDepthBuffer();

    // create vertices
    vector<Vertex> vertices;
    vertices.push_back(Vertex( 0.0f, -0.5f, 0.5f, 255, 0, 0));
    vertices.push_back(Vertex(-0.5f,  0.5f, 0.5f, 255, 0, 0));
    vertices.push_back(Vertex( 0.5f,  0.5f, 0.5f, 255, 0, 0));
    vertices.push_back(Vertex( 0.2f, -0.2f, 0.8f, 0, 255, 0));
    vertices.push_back(Vertex( 0.0f,  0.2f, 0.8f, 0, 255, 0));
    vertices.push_back(Vertex( 0.6f,  0.2f, 0.8f, 0, 255, 0));

    // create vertex format
    glfVertexFormat vertexFormat;
    vertexFormat.AddAttribute(glfVertexFormat::ATTRIB_POSITION, GL_FLOAT, 3);
    vertexFormat.AddAttribute(glfVertexFormat::ATTRIB_COLOR, GL_UNSIGNED_BYTE, 4);

    // create vertex buffer
    glfVertexBuffer vertexBuffer;
    vertexBuffer.Create(vertices, vertexFormat);

    // create element buffer
    std::vector<unsigned char> indices;
    indices.push_back(0);
    indices.push_back(1);
    indices.push_back(2);
    indices.push_back(3);
    indices.push_back(4);
    indices.push_back(5);
    indices.push_back(6);
    glfElementBuffer elementBuffer;
    elementBuffer.Create(indices, GL_TRIANGLES);

    // create depth buffer mode
    glfDepthBufferMode depthBufferMode;
    depthBufferMode.SetDepthTest(true);

    // create viewport
    glfViewport viewport;
    viewport.SetOrigin(0, 0);
    viewport.SetSize(640, 480);

    // create and draw batch
    glfBatch batch;
    batch.SetDepthBufferMode(&depthBufferMode);
    batch.SetVertexBuffer(&vertexBuffer);
    batch.SetElementBuffer(&elementBuffer);
    batch.SetViewport(&viewport);
    batch.Draw();

    // grab framebuffer and write to files
    Image<unsigned char> image;
    context->Grab(image, glfRenderingContext::GRAB_COLOR);

    //if (ImageIO::Save("color.mip", image) != 0) {
    if (ImageIO::Save("color.mip", image) != 0) {
      return -1;
    }
    context->Grab(image, glfRenderingContext::GRAB_DEPTH);
    //if (ImageIO::Save("depth.mip", image) != 0) {
    if (ImageIO::Save("depth.mip", image) != 0) {
      return -1;
    }
    context->Grab(image, glfRenderingContext::GRAB_STENCIL);
    //if (ImageIO::Save("stencil.mip", image) != 0) {
    if (ImageIO::Save("stencil.mip", image) != 0) {
      return -1;
    }

    // clean up and exit
    context->Destroy();

  } catch (glfException& e) {
    context->Destroy();
    std::cout << "Error: " << e.GetMessageString() << std::endl;
    return -1;
  }

  return 0;
}