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Graphics / [SFML2] RenderImage completely transparent

« on: January 19, 2011, 07:47:26 pm »

Hello all,

I have recently upgraded to SFML2 because I required the offscreen rendering that RenderImage supports. Sadly, I seem to be doing something wrong.

Code: [Select]

/*
 * main.cpp
 *
 *  Created on: Jan 17, 2011
 *      Author: renolc
 */

#include <SFML/Graphics.hpp>
#include <SFML/OpenGL.hpp>
#include <stdlib.h>
#include <stdio.h>

int main() {

// create image
if (!sf::RenderImage::IsAvailable())
return EXIT_FAILURE;
sf::RenderImage image;
if (!image.Create(800, 600, true))
return EXIT_FAILURE;
image.SetActive(true);

// opengl /////////////////////////////////////////////////////////////////

// clear value
glClearDepth(1);
glClearColor(0, 0, 0, 1);

// enable depth
glEnable(GL_DEPTH_TEST);
glDepthMask(GL_TRUE);
glDepthFunc(GL_LEQUAL);
glHint(GL_PERSPECTIVE_CORRECTION_HINT, GL_NICEST);

// setup perspective
glViewport(0, 0, image.GetWidth(), image.GetHeight());
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
gluPerspective(45, (double)image.GetWidth()/(double)image.GetHeight(), 1, 50);
glMatrixMode(GL_MODELVIEW);

// light
GLfloat position[] = {0, 0, 2, 1};
glLightfv(GL_LIGHT0, GL_POSITION, position);
glEnable(GL_LIGHTING);
glEnable(GL_LIGHT0);
glColorMaterial(GL_FRONT, GL_AMBIENT_AND_DIFFUSE);
glEnable(GL_COLOR_MATERIAL);
glShadeModel(GL_SMOOTH);

// clear screen
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

// draw stuff
glLoadIdentity();
glTranslated(0, 0, -10);
glBegin(GL_QUADS);
glColor3d(1, 0, 0);
glVertex3d(-5, -3, 0.5);
glVertex3d(-5, 0, 0.5);
glVertex3d(-1, 0, -0.5);
glVertex3d(-1, -3, -0.5);

glColor3d(0, 1, 0);
glVertex3d(1, -3, -0.5);
glVertex3d(1, 0, -0.5);
glVertex3d(5, 0, 0.5);
glVertex3d(5, -3, 0.5);

glColor3d(0, 0, 1);
glVertex3d(-2.5, 0.5, 0);
glVertex3d(-2.5, 3.5, 0);
glVertex3d(2.5, 3.5, 0);
glVertex3d(2.5, 0.5, 0);
glEnd();

// \opengl ////////////////////////////////////////////////////////////////

// update image
image.Display();

// save image of rendering
image.GetImage().SaveToFile("test.png");

return EXIT_SUCCESS;
}



If I replace RenderImage with RenderWindow, it works perfectly. But if I try it as written above, it only outputs a completely transparent image.

I suspect it is something I am doing wrong, since I am still relatively new to SFML2 and OpenGL in general, so I would appreciate any help.

Thanks in advance!