Messages

1

Graphics / Starting With OpenGL

« on: January 06, 2014, 12:00:42 am »

I am attempting to run the first example on the openGL tutorial.

http://sfml-dev.org/tutorials/2.1/window-opengl.php

I receive errors as follows:

1>main.obj : error LNK2019: unresolved external symbol __imp__glClear@4 referenced in function _main
1>main.obj : error LNK2019: unresolved external symbol __imp__glViewport@16 referenced in function _main

I believe there is a file named opengl32.lib that I have to do something with. Some of the guides tell me the location, so maybe I need to copy it to my project? Some tell me things about other libraries like glu and ones I obviously don't need like glut. And finally there are a few tutorials telling me that I can put a linker option (which I assume goes in Linker command line options). Nothing I try is working and I'm getting very frustrating and I have over a hundred tabs of tutorials I've tried and I don't know why this is so complicated.

I am using Microsoft Visual C++ 2010.

2

Graphics / Re: Creating Large Number Of Stars Efficiently

« on: January 05, 2014, 10:43:49 pm »

Thanks for your help with that error.

At the moment, the blur shader doesn't appear to be having any effect. I know it is loading because the whole screen turned purple when I tested.

However, when I restore it to the normal shader code, the screen appears unchanged.

uniform sampler2D texture;
uniform float blur_radius;

void main()
{
    vec2 offx = vec2(blur_radius, 0.0);
    vec2 offy = vec2(0.0, blur_radius);

    vec4 pixel = texture2D(texture, gl_TexCoord[0].xy) * 4.0 +
                 texture2D(texture, gl_TexCoord[0].xy - offx) * 2.0 +
                 texture2D(texture, gl_TexCoord[0].xy + offx) * 2.0 +
                 texture2D(texture, gl_TexCoord[0].xy - offy) * 2.0 +
                 texture2D(texture, gl_TexCoord[0].xy + offy) * 2.0 +
                 texture2D(texture, gl_TexCoord[0].xy - offx - offy) * 1.0 +
                 texture2D(texture, gl_TexCoord[0].xy - offx + offy) * 1.0 +
                 texture2D(texture, gl_TexCoord[0].xy + offx - offy) * 1.0 +
                 texture2D(texture, gl_TexCoord[0].xy + offx + offy) * 1.0;

    gl_FragColor = gl_Color * (pixel / 16.0);
}

I tried manually filling in the blur_radius, in case I had to fill that in. I tried both 4.0 and 1.0. I notice no difference to the screen except strange random horizontal and vertical lines all the way across the screen, the same colour as some of the stars.

I also tried to change the code a bit like this to see if that would do anything:

  vec4 pixel = texture2D(texture, gl_TexCoord[0].xy) * 0.0 +
               texture2D(texture, gl_TexCoord[0].xy - offx) * 2.5 +
               texture2D(texture, gl_TexCoord[0].xy + offx) * 2.5 +
               texture2D(texture, gl_TexCoord[0].xy - offy) * 2.5 +
               texture2D(texture, gl_TexCoord[0].xy + offy) * 2.5 +
               texture2D(texture, gl_TexCoord[0].xy - offx - offy) * 1.5 +
               texture2D(texture, gl_TexCoord[0].xy - offx + offy) * 1.5 +
               texture2D(texture, gl_TexCoord[0].xy + offx - offy) * 1.5 +
               texture2D(texture, gl_TexCoord[0].xy + offx + offy) * 1.5;

Here is the code:

        sf::Shader blur;
        if (sf::Shader::isAvailable())
        {
                if (!blur.loadFromFile("blur.frag", sf::Shader::Fragment))
                {
                        std::cout << "Could Not Load Blur Shader!" <<std::endl;
                }
        }
        else
        {
                std::cout << "Error! Shaders Not Supported!" <<std::endl;
        }
        sf::RenderTexture blurtexture;
        if (!blurtexture.create(sf::VideoMode::getDesktopMode().width, sf::VideoMode::getDesktopMode().height))
        {
                std::cout << "Error Creating BlurTexture!" << std::endl;
        }

                blurtexture.clear(sf::Color::Black);
                blurtexture.draw(smallstars);
                for (i = 0; i < LARGESTAR_COUNT; i ++) {
                        blurtexture.draw(largestars[i]);
                }
                blurtexture.display();
                sf::Sprite blursprite(blurtexture.getTexture());

        window.clear(sf::Color::Black);
        window.draw(blursprite, &blur);
        window.display();

3

Graphics / Build a Realistic Sphere

« on: January 05, 2014, 07:44:48 pm »

I am currently able to build nice beautiful circles like this:

void resetPlanetVertexes (sf::VertexArray* planet, sf::Vector2f* center, float size, sf::Color* color)
{
        int i;
        int count = (int)(planet->getVertexCount());
        for (i = 1; i < count-1; i ++) {
                float angle = ((float)(i) / (float)(count-2) * 360.f) * 3.14f / 180.f;
                ((*planet)[i]).position = *center + sf::Vector2f(
                        (float)(std::cos(angle) * size),
                        (float)(std::sin(angle) * size)
                );
                ((*planet)[i]).color = *color;
        }
        ((*planet)[count-1]).position = ((*planet)[1]).position;
        ((*planet)[count-1]).color = ((*planet)[1]).color;
}

void buildPlanet (sf::VertexArray* planet, sf::RenderWindow* window)
{
        int width = (int)(window->getSize().x);
        int height = (int)(window->getSize().y);
        sf::Color planetcolor = getPlanetColor();
        float size = getPlanetSize();
        std::cout << "Planet Size: " << size << std::endl;
        sf::Vertex* planetcenter = &((*planet)[0]);
        planetcenter->position = sf::Vector2f
                                ((float)(rand() % (width + (PLANET_BORDER<<1)))-PLANET_BORDER,
                                (float)(rand() % (height + (PLANET_BORDER<<1)))-PLANET_BORDER);
        planetcenter->color = planetcolor;
        resetPlanetVertexes(planet, &(planetcenter->position), size, &(planetcenter->color));
}

However, they look obviously flat and not like planets at all. They look like someone cut perfect circles out of construction paper.



If we look at a planet like Neptune, we see that the bottom right fades towards black, while the top left fades towards a slightly brighter color to create the appearance of a sphere and not a circle.

I think I can probably do something with the coloring to darken or lighten it. (Not sure the best way to do that.) Do I really have to modify each of the three rgb values to lighten/darken a colour?

I also thought there might be a way to build a 3D planet or something similar to that as well.

I want to make each planet random and different so I don't want to use a standard sprite.

4

Graphics / Re: Creating Large Number Of Stars Efficiently

« on: January 05, 2014, 03:30:31 am »

I'm doing another attempt, this time using the sf::TrianglesFan to create gradient triangles in a circle around the central star. Here's the code:

        sf::VertexArray examplestar(sf::TrianglesFan, 8);
        buildStarExample(&examplestar, &window);

void buildStarExample (sf::VertexArray* star, sf::RenderWindow* window)
{
        int width = (int)(window->getSize().x);
        int height = (int)(window->getSize().y);
        float size = 30.f;

        sf::Vector2f center = sf::Vector2f
                                ((float)(rand() % width),
                                (float)(rand() % height));
        ((*star)[0]).position = center;
        std::cout << center.x << " - " << center.y << std::endl;
        ((*star)[0]).color = sf::Color((rand()%64)+192, (rand()%64)+192, rand()%256, 255);

        unsigned int i;
        for (i = 0; i < star->getVertexCount(); i ++) {
                float angle = ((float)(i) / (float)(star->getVertexCount()) * 360.f) * 3.14f / 180.f;
                ((*star)[i]).position = center + sf::Vector2f(
                        (float)(std::cos(angle) * size),
                        (float)(std::sin(angle) * size)
                );
                ((*star)[i]).color = ((*star)[0]).color;
                //((*star)[i]).color.a = 0;
        }
}

At the moment, it's a solid octagon shape. The moment I uncomment the line '((*star)).color.a = 0;', the whole star disappears. I expect the center to be solid, and the edges transparent. Why is it not fading to transparent?

5

Graphics / Re: Failing To Load Font

« on: January 05, 2014, 02:34:27 am »

Thanks For Your Help!

I now have a beautiful text title!


On this page here:
http://www.sfml-dev.org/tutorials/2.0/start-vc.php

I would suggest to also highlight in red the 'Configuration: Release' as it comes up by default in Debug. Or, set the files to -d instead.


And perhaps the note from below that table can be included in the text and fonts tutorial, to be extra safe.

6

Graphics / Re: Creating Large Number Of Stars Efficiently

« on: January 05, 2014, 02:15:45 am »

Okay I've made 30,000 beautiful pixelated stars using a VertexArray.

I'd now like to make them not pixelated, and more like shining stars.

I tried to apply a blur shader which Laurent made here:
https://github.com/SFML/SFML/blob/master/examples/shader/resources/blur.frag

However it seems to make the stars invisible. I modified the last line to 'gl_FragColor = gl_Color' and everything showed up okay.

Next, I did a simple test to make each pixel purple. 'gl_FragColor = vec4(1.0, 0.0, 1.0, 1.0);'

So, it seems that I can only control the single individual pixel, and in order to make the stars more realistic, I obviously would have to brighten the surrounding pixels somewhat. Is this possible with shaders and how would I go about doing it?

7

Graphics / Re: Failing To Load Font

« on: January 04, 2014, 12:25:35 am »

By debug-mode, do you mean this:



And by release libs, are they under linker > additional dependencies?



I tried to change each name to add a -d for debug, but the error persists. I am now trying from scratch with the arial font from Windows/fonts.

#include <SFML/Graphics.hpp>
#include <iostream>

int main () {

        sf::Font font;
        if (!font.loadFromFile("arial.ttf"))
        {
                std::cout << "Load Failed!" <<std::endl;
                return 0;
        }

        sf::RenderWindow window(sf::VideoMode(200, 200), "SFML Text Test!");
        sf::Text text;

        // select the font
        text.setFont(font); // font is a sf::Font

        // set the string to display
        text.setString("Hello world");

        // set the character size
        text.setCharacterSize(24); // in pixels, not points!

        // set the color
        text.setColor(sf::Color::Red);

        // set the text style
        text.setStyle(sf::Text::Bold | sf::Text::Underlined);

    while (window.isOpen())
    {
        sf::Event event;
        while (window.pollEvent(event))
        {
            if (event.type == sf::Event::Closed)
                window.close();
        }

        window.clear();
        window.draw(text);
        window.display();
    }

    return 0;
}

It runs into that error before even going into the failure code.

8

Graphics / Re: Creating Large Number Of Stars Efficiently

« on: January 03, 2014, 11:38:26 pm »

I thought that this may be faster.

It still takes about a second to load the texture now with just 2500 stars in 1000x1000. I'm wondering if there is a faster way to set pixels...

void buildStarTexture (sf::RenderTexture* texture)
{
        sf::CircleShape star(1, 4);
        int i;
       
        if (!texture->create(STAR_TEXTURE_WIDTH, STAR_TEXTURE_HEIGHT))
        {
                // error...
        }
        texture->clear();
        star.setFillColor(sf::Color::Yellow);
        for (i = 0; i < STAR_TEXTURE_YELLOW; i ++) {
                star.setPosition(rand() % STAR_TEXTURE_WIDTH, rand() % STAR_TEXTURE_HEIGHT);
                texture->draw(star);
        }
        star.setFillColor(sf::Color::White);
        for (i = 0; i < STAR_TEXTURE_WHITE; i ++) {
                star.setPosition(rand() % STAR_TEXTURE_WIDTH, rand() % STAR_TEXTURE_HEIGHT);
                texture->draw(star);
        }
        texture->display();
}

9

SFML website / Think This Is A Typo

« on: January 03, 2014, 11:28:06 pm »

On this page:
http://www.sfml-dev.org/tutorials/2.0/graphics-draw.php

You have this text in the Off-screen drawing section:

sf::Texture& texture = renderTexture.getTexture();

// draw it to the window
sf::Sprite sprite(texture);

I think the ampersand is a typo.

10

Graphics / Failing To Load Font

« on: January 03, 2014, 10:52:12 pm »

My program:

int main()
{
        sf::Font font;
        if (!font.loadFromFile("Xolonium-Regular.otf"))
        {
                // error...
        }
    sf::RenderWindow window(sf::VideoMode::getDesktopMode(), "SFML works!", sf::Style::Fullscreen);
        window.setVerticalSyncEnabled(true);

        sf::Text title;
        title.setFont(font); // font is a sf::Font
        title.setString("Hello World!");
        title.setCharacterSize(64); // in pixels, not points!
        title.setColor(sf::Color::White);

    while (window.isOpen())
    {
        sf::Event event;
        while (window.pollEvent(event))
        {
                        switch (event.type)
                        {
                                case sf::Event::KeyPressed: //Key pressed
                                        switch (event.key.code)
                                        {
                                        case sf::Keyboard::Escape:
                                                window.close();
                                                break;
                                        }
                                        break;
                        }
        }

        // clear the window with black color
        window.clear(sf::Color::Black);
               
        window.draw(title);
        window.display();
    }

    return 0;
}

Displays this weird text in the command prompt:



And displays this dialog:



According to this thread, OTF format should be supported:
http://en.sfml-dev.org/forums/index.php?topic=72.0

When I open the font it works fine to view in Windows. It's a font that's available on this site here:
http://www.fontspace.com/severin-meyer/xolonium

The font is in the same directory as sfml-graphics-2.dll and others... which I assume is the correct directory. It seems awfully strange if this is simply failing to find the file.

11

Graphics / Creating Large Number Of Stars Efficiently

« on: January 03, 2014, 10:15:23 pm »

I'm hoping to create a background which is randomized with lots of stars for a space-themed game. The stars all move in the same direction at the same time to simulate motion. There will be a lot of them, and I'd really like to create an efficient system.

I want it randomized, so it's not the same graphic over and over. What is the most efficient way to do this?

Do I want to create an array of star objects, similar to this code which doesn't work:

sf::CircleShape stars[] = sf::CircleShape[500];

Or is it recommended to do something more fancy, such as creating a random Image on the fly which is then moved in one piece?