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Frequently Asked Questions

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masterex1000 edited this page Jul 1, 2022 · 36 revisions

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Can I run raylib in my old PC?

Yes, you can. raylib comes compiled by default for OpenGL 3.3 backend but it can be recompiled for older OpenGL versions! It can be recompiled for OpenGL 1.1 (1997) and OpenGL 2.1 (2006). To do that using Notepad++, just follow this steps:

  1. Open file C:\raylib\raylib\src\core.c
  2. Execute Notepad++ script: raylib_source_compile but choose the desired OpenGL API version:
SET GRAPHIC_API=GRAPHICS_API_OPENGL_11
SET GRAPHIC_API=GRAPHICS_API_OPENGL_21
SET GRAPHIC_API=GRAPHICS_API_OPENGL_33
  1. Open any raylib example or your raylib game
  2. Execute Notepad++ script: raylib_compile_execute

Note that above process only needs to be done once, if at some point you need to change OpenGL version again, just repeat that process.

What are the default paths?

Like any other library or project, a raylib project requires different dependencies placed accordingly for a correct compilation. It means external library headers and, eventually, some static library.

Dependencies depend on platform, so every platform requires some libraries installed in an specific folder to be accesible for the compiler when compiling raylib or a raylib example/game.

Specific dependencies installation is listed for every platform on this Wiki. Actually, there are not many external dependencies for raylib, only a couple (GLFW3, OpenAL Soft) and only in some platforms.

On Linux, both the make and cmake build systems install libraylib and raylib.h to /usr/local/lib and /usr/local/include, respectively. If you want to customize these locations, inspect the appropriate Makefile or CMakeLists.txt.

What are the dependencies on Windows?

For Windows platform, raylib is distributed with a self-contained installer that includes, not only raylib but also a raylib-ready-configured free text editor (Notepad++) and a C/C++ compiler with tools (MinGW).

Notepad++ comes with a bunch of pre-created scripts ready for compiling a raylib project and raylib source for different platforms. Those scripts assume that raylib is installed in the portable folder path: C:\raylib

In some cases, it could happen that user decided to move that folder to somewhere else; in that case, raylib paths need to be reconfigured, just updating the RAYLIB_PATH variable at the beginning of every script.

As a recommendation, if you move C:\raylib folder to somewhere else, try to avoid spaces and special characters on the new path, it could generate errors on compilation.

For command-line compilation and custom pipeline configuration, just check Compile for Windows wiki.

This page will go over some of the common questions new users have when starting out using raylib.

How do I remove the log?

Call SetTraceLogLevel(LOG_NONE) before InitWindow()

How do I make a timer?

raylib has no built in timer system. You are expected to keep track of time in your own code. You can do with with the GetTime() and GetFrameTime() functions. Below is an example of a simple timer struct and functions to use it.

typedef struct Timer {
    double startTime;   // Start time (seconds)
    double lifeTime;    // Lifetime (seconds)
} Timer;

void StartTimer(Timer *timer, double lifetime)
{
    timer->startTime = GetTime();
    timer->lifeTime = lifetime;
}

bool TimerDone(Timer timer)
{
    return GetTime() - timer.startTime >= timer.lifeTime;
}

double GetElapsed(Timer timer)
{
    return GetTime() - timer.startTime;
}

You can see a short video on the concept here: https://youtu.be/vGlvTWUctTQ

What do all the fields in Camera2D mean?

Video explaining Camera2D: https://youtu.be/zkjDU3zmk40

The Camera2D structure is used by BeginMode2D()/EndMode2D() to define a 2d transformation. This is very useful for games that want to draw a 2d world in a fixed coordinate system and have the ability to pan, zoom and rotate the view without the need to change drawing code.

Fields

typedef struct Camera2D {
    Vector2 offset;         // Camera offset (displacement from target)
    Vector2 target;         // Camera target (rotation and zoom origin)
    float rotation;         // Camera rotation in degrees
    float zoom;             // Camera zoom (scaling), should be 1.0f by default
} Camera2D;

Offset

The offset is used to shift the window origin away from the default of the upper left corner. it is a value defined in screen space. it is not affected by rotation or zoom. It is very common to set this to be half the window width/height in order to make the window origin be the center of the screen.

Target

This is a point in world space that the camera will follow. It defines zoom and rotation pivot points. It is very common to set this value to the thing you want to track in your world, such as your player position.

Rotation

This is the rotation angle that the view will be rotated by. It will rotate around the target point in world coordinates.

Zoom

This is the scale factor applied to the view. A value of 1 will draw the world at it's original scale. A value of 2 will be a 2x zoom and draw everything twice as large on screen.

Converting Coordinates

There will be times when you need to convert from screen coordinates into world coordinates, such as wanting to find out what the mouse's screen position is in the world.

GetScreenToWorld2D()

Vector2 GetScreenToWorld2D(Vector2 position, Camera2D camera);

This will convert a screen point into a world point for a camera. This will include zoom and scale. It is very common to use this to get the mouse position in world coordinates to do collisions or picking.

Vector2 mouseInWorld = GetScreenToWorld2D(GetMousePosition(), MyCamera);

GetWorldToScreen2D()

Vector2 GetWorldToScreen2D(Vector2 position, Camera2D camera);

This function gets a screen point for a world point, using zoom and scale. It is useful for computing the location of HUD elements that should not be scaled or rotated with the world view, such as player names, health bars, or other labels.

How do I center text on the screen?

raylib does not offer any text formatting functions, so you need to compute the starting point for all text that you draw. The starting point for text is always the upper left corner.

You can compute the center of the screen by dividing the screen width and hieght in half.

int screenCenterX = GetScreenWidth() / 2;
int screenCenterY = GetScreenHeight() / 2;

Next you need to compute how large the text is, and offset the center by half the text size.

const char text[] = "Congrats! You created your first window!";

int fontSize = 20;
int textWidth = MeasureText(text, fontSize);

int textStartX = screenCenterX - textWidth / 2;
int textStartY = screenCenterY - fontSize / 2;

DrawText(text, textStartX, textStartY, fontSize, LIGHTGRAY);

MeasureText() only measures the width of text, but takes fewer arguments. It is often acceptable to just use the font size as the total text height, but for some fonts, this may not be accurate. MeasureTextEx() will measure both height and width of text, but does take more arguments. For this reason it is used less often.

Why does calling LoadTexture() crash my program?

You are likely calling LoadTexture() before calling InitWindow(). Loading textures requires a valid OpenGL context, that InitWindow() sets up. Therefore, textures cannot be loaded before calling InitWindow().

How can I draw a texture flipped?

Drawing a texture flipped requires the use of either DrawTextureRec(), or DrawTexturePro() functions. Every single texture drawing function calls DrawTexturePro() to do its work, but only these two expose the parameters necessary to flip a texture: the source rectangle.

To flip the texture, simply pass a source rectangle with a negative width or height. Note that this functionality is custom from raylib.

Rectangle source = { 0, 0, -texture.width, texture.height };

DrawTextureRec(texture, source, (Vector2){ 0, 0 }, WHITE);

The above code will draw a texture flipped in the X axis.

Why is my render texture upside down?

All textures in OpenGL by default have the origin in the lower-left corner, while the screen origin is by default configured in the upper left corner. When you load a normal texture, raylib flips the image data for you, however this cannot be done with a render texture. The solution is to draw your render texture vertically flipped, see the above paragraph for how to do this.

How do I create a depth texture?

By default LoadRenderTexture() uses a RenderBuffer for the depth texture, this is done for optimization (supposedly GPU can work faster if it knows that depth texture does not need to be read back). But a RenderBuffer is unsuitable to be drawn on the screen like a regular Texture2D.

Here some code to load a RenderTexture2D that uses a Texture2Dfor the depth:

RenderTexture2D LoadRenderTextureWithDepthTexture(int width, int height)
{
    RenderTexture2D target = {0};

    target.id = rlLoadFramebuffer(width, height);   // Load an empty framebuffer

    if (target.id > 0)
    {
        rlEnableFramebuffer(target.id);

        // Create color texture (default to RGBA)
        target.texture.id = rlLoadTexture(NULL, width, height, PIXELFORMAT_UNCOMPRESSED_R8G8B8A8, 1);
        target.texture.width = width;
        target.texture.height = height;
        target.texture.format = PIXELFORMAT_UNCOMPRESSED_R8G8B8A8;
        target.texture.mipmaps = 1;

        // Create depth texture
        target.depth.id = rlLoadTextureDepth(width, height, false);
        target.depth.width = width;
        target.depth.height = height;
        target.depth.format = 19;       //DEPTH_COMPONENT_24BIT?
        target.depth.mipmaps = 1;

        // Attach color texture and depth texture to FBO
        rlFramebufferAttach(target.id, target.texture.id, RL_ATTACHMENT_COLOR_CHANNEL0, RL_ATTACHMENT_TEXTURE2D, 0);
        rlFramebufferAttach(target.id, target.depth.id, RL_ATTACHMENT_DEPTH, RL_ATTACHMENT_TEXTURE2D, 0);

        // Check if fbo is complete with attachments (valid)
        if (rlFramebufferComplete(target.id)) TRACELOG(LOG_INFO, "FBO: [ID %i] Framebuffer object created successfully", target.id);

        rlDisableFramebuffer();
    } 
    else TRACELOG(LOG_WARNING, "FBO: Framebuffer object can not be created");

    return target;
}

Now the RenderTexture depth texture can be drawn as a regular texture... but note that information contained is not normalized!

Why is my font blurry?

If you call LoadFont(), the text will be loaded at a fixed size (32 pixels height). If you draw this text at anything other than this fixed size (32 pixles height for .ttf/.otf fonts), the font texture will be scaled. Scaling introduces artifacts. Scaling up will introduce blur. You can load your font with LoadFontEx() and specify the size you want to use it at for the best possible quality. You can pass in NULL for fontChars and 0 for glyphCount to load the default character set.

LoadFontEx("myfont.ttf", 50, NULL, 0);

How do I load my 3d model animations in raylib?

3d animations is a complex topic. raylib supports IQM file-format animations loading but there are multiple ways to create them and export the IQM file, it is very possible that depending on that process raylib could not load animations from IQM file. GLTF file-format also supports animation but raylib is not able to load them at this moment. For anyone adventurous enough to try to implement GLTF animations support in raylib, you can check rmodels.c module and LoadGLTF() function implementation.

Does raylib support Vulkan? Will raylib support it?

Raylib is built on top of OpenGL, and there are current no plans to support any other graphics APIs. In any case, raylib uses rlgl as its abstraction layer to support different OpenGL versions. Theoretically a vulkan equvalent could be developed that maps raylib's calls to a Vulkan backend, but creating that layer would take a considerable amount of work.

Why are my assets not loading?

File loading functions such as LoadTexture() check the current working directory for the file. Usually the working directory should be where the executable is located, but depending on OS and build system this is not always the case. A quick fix for this is to use ChangeDirectory(GetApplicationDirectory()); before loading your assets.

Why are my sound files not working?

If you're getting Failed to open file, see the above question. If you're getting warnings like Failed to get frame count for format conversion, there are two possible causes:

  • The audio device is not initialized, it must be initialized with InitAudioDevice() before any sounds can be loaded.
  • The audio file is corrupted or not supported by raylib, try converting it to another format or using a different file.

How do I remove the console window?

It can be removed with a compiler parameter, it depends on the platform and compiler. gcc supports -Wl,--subsystem,windows or -mwindows compiler options. On Visual Studio, in Configuration Properties > Linker > System > SubSystem choose Windows (/SUBSYSTEM:WINDOWS) to avoid console. With other compilers there should be similar options.

How do I setup a custom icon for my executable?

Icon support on executables is only supported PE executables, usually on Windows systems. Icon can be embedded as a resource in code compilation, when creating the executable or it can be changed at runtime on execution.

  1. To embed the icon as a resource on code compilation, a resource.rc file should be created and compiled into an object file to be embedded as a regular code file. To compile that resource file, MinGW provides a tool called windres.exe:
windres resource.rc -o resource.rc.data --target=pe-x86-64

With Visual Studio, adding the resource.rc file to the project should be enough.

  1. To change the icon at runtime, raylib provides function SetWindowIcon(Image image), just make sure that image.format is PIXELFORMAT_UNCOMPRESSED_R8G8B8A8, it's a requirement.

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