Method refresh

src/Engine/OpenGL.cpp:139–212

  }

  void OpenGL::refresh(bool smooth, unsigned inwidth, unsigned inheight, unsigned outwidth, unsigned outheight, int topBlackBand, int bottomBlackBand, int leftBlackBand, int rightBlackBand) {
    while (glGetError() != GL_NO_ERROR); // clear possible error from who knows where
	clear();
    if(shader_support && (fragmentshader || vertexshader)) {    
      glUseProgram(glprogram);
      GLint location;

      float inputSize[2] = { (float)inwidth, (float)inheight };
      location = glGetUniformLocation(glprogram, "rubyInputSize");
      glUniform2fv(location, 1, inputSize);

      float outputSize[2] = { (float)outwidth, (float)outheight };
      location = glGetUniformLocation(glprogram, "rubyOutputSize");
      glUniform2fv(location, 1, outputSize);

      float textureSize[2] = { (float)iwidth, (float)iheight };
      location = glGetUniformLocation(glprogram, "rubyTextureSize");
      glUniform2fv(location, 1, textureSize);
    }

	glErrorCheck();

    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_BORDER);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_BORDER);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, smooth ? GL_LINEAR : GL_NEAREST);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, smooth ? GL_LINEAR : GL_NEAREST);

	glErrorCheck();

    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    glOrtho(0, outwidth, 0, outheight, -1.0, 1.0);
    glViewport(0, 0, outwidth, outheight);

    glMatrixMode(GL_MODELVIEW);
    glLoadIdentity();

	glErrorCheck();

    glPixelStorei(GL_UNPACK_ROW_LENGTH, buffer_surface->getSurface()->pitch / buffer_surface->getSurface()->format->BytesPerPixel);

	glErrorCheck();

    glTexSubImage2D(GL_TEXTURE_2D,
      /* mip-map level = */ 0, /* x = */ 0, /* y = */ 0,
      iwidth, iheight, GL_BGRA, iformat, buffer);


    //OpenGL projection sets 0,0 as *bottom-left* of screen.
    //therefore, below vertices flip image to support top-left source.
    //texture range = x1:0.0, y1:0.0, x2:1.0, y2:1.0
    //vertex range = x1:0, y1:0, x2:width, y2:height
    double w = double(inwidth)  / double(iwidth);
    double h = double(inheight) / double(iheight);
    int u1 = leftBlackBand;
    int u2 = outwidth - rightBlackBand;
    int v1 = outheight - topBlackBand;
    int v2 = bottomBlackBand;