Simple DirectMedia Layer (SDL) is a cross-platform multimedia library designed to provide low level access to audio, keyboard, mouse, joystick, 3D hardware via OpenGL, and 2D video framebuffer.

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Segmentation fault adding SDL_Surface

I'm trying to add a new SDL_Surface to my whack-a-mole clone code but even if I set it to null it wont let me. game.h #include<SDL2/SDL.h> #include<SDL2/SDL_image.h> ...
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0answers
39 views

Looking for 2D engine in Linux environment for top down style game [on hold]

I'd like to start getting into game development and wanted to know what tools/engines would best fit me. I am working in a Linux environment and my programming background is C/C++/Java and some Perl. ...
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2answers
144 views

Moving one object from one point to another with acceleration

How would someone implement moving an object from one point in 2D space to another using these formulae to update objects: m_position.setX/Y( m_position.X/Y() + m_velocity.X/Y() * dt + 0.5 * m_acc * ...
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1answer
162 views

SDL & OpenGL - Artifacts when multisampling

Im trying to render a model with anialiasing using OpenGL and SDL, but when I do I get strange artifacts. When I render with antialiasing disabled everything looks fine. When antialiasing is ...
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1answer
28 views

Bouncing projectile off of sprite, the sides work but top and bottom do not

I'm having a problem bouncing a projectile off a sprite, we've been asked to move the projectile using the equations of motions which makes things a little more difficult but as far as I can see what ...
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1answer
28 views

Fastest way to render image data from buffer

Currently I am doing my rendering by using a 3D array window_width x window_height x rgb as a buffer, then looping through the buffer and plotting pixels on screen using SDL2 (SDL_RenderDrawPoint). I ...
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1answer
72 views

Where can I get correct pitch parameter for SDL_RenderReadPixels function in SDL2?

I have a texture created with SDL_TEXTUREACCESS_TARGET access and I want to get all it's pixels with SDL_RenderReadPixels() function. One of the function parameters is pitch and I don't really know ...
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1answer
70 views

Redefining the SDL rect struct

Upon checking the docs of SDL (1.2) I saw that the SDL_Rect struct defines the x and y as Sint16. I'm making a bitmap font text scroller and I need those specifically to be unsigned ints because the ...
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1answer
56 views

Keyboard input vs character movement encapsulation

In our game created with c++ and sdl we are having difficulty delegating how the main character should be controlled. We have a keyboard class and a sprite class for the main character, but are ...
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2answers
144 views

Translating an object in the rotation direction

I am creating a graphical scene with OpenGL and SDL, and I'm running into a problem in regards to translating an object in its rotation direction. Each of the graphical objects in the scene has a ...
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3answers
232 views

Problem getting mouse events while keys held down in SDL2

I'm attempting to write input capturing code using SDL2 on Windows. However, I'm running into a problem. Whenever a key is held down, the SDL event queue has no mouse movement, nor will the mouse ...
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0answers
46 views

Entity to tile collision detection (C++, SDL)

I'm currently trying to handle collisions between entities and a tilemap, but I've hit a problem. My tiles are stored simply as integer tile IDs in a multidimensional array, and I wanted to perform a ...
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2answers
92 views

SDL draw dynamic select box

this might seem obvious to many, but I'm stuck and I cannot find any tutorial which helped me, so it would be great to find the answer here. I tried to make a rectangle like you have in RTS games, so ...
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1answer
66 views

Should I cull off-screen objects in SDL2

My game will have a large number of objects moving offscreen at any given time, can i just render them all with SDL_RenderCopy even though they are off screen or should I only render them if they are ...
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3answers
1k views

What is the contents of the buffer *after* a call to glSwapBuffers()?

(SDL_GL_SwapBuffers() in particular) When you have drawn a scene, and you call swap-buffers, it is routine to then glClear() the scene before drawing anything; if you don't clear, what is the ...
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0answers
31 views

Passing an SDL KeyboardState(Uint8*) to Lua

I'm working on my first big project and I've decided to integrate Lua with my C++ framework. Everything's worked out so far, but the only way I've managed to pass the SDL_GetKeyboardState(NULL) array ...
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3answers
4k views

Smooth Sprite Movement - Don't Add Velocity to Position?

I am trying to figure out if there is a way to move a sprite smoothly on the screen at different speeds without stuttering, but keeping the effect that it's moving smoothly; especially at faster ...
2
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1answer
173 views

Rendering text with SDL2 and OpenGL

I've been trying to have text rendering in my OpenGL scene using SDL2. The tutorial I came across is this one Rendering text I followed the same code, and I get text rendering fine. However the issue ...
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0answers
36 views

SDL_Mixer - Mix_LoadWav_RW returns NULL (Unrecognized sound file type)

I am loading sounds from resource file (Doom2.wad from game Doom 2: Hell on Earth), converting them into WAVE and then trying to play them using SDL_Mixer. If I save the converted sound into a .wav ...
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2answers
103 views

Colour values of a pixel array from a spritesheet image wrong (C++, SDL2)

So basically what i want to do is create a 2D tile based rendering system in C++ that renders each pixel on the screen manually. Rendering an individual pixel on the screen works just fine (or render ...
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1answer
89 views

Is this a good way to regulate fps?

In all of my tests I always regulate the fps by using this method. const int fps = 30; const int msPerFrame = 1000/fps; // 33 ms per frame, so it's more like 30.3030 fps while(true) { const int ...
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1answer
44 views

Box platform collision

I'm working on a platform game and my collision code is to picky. I can't exactly do aabb(?) because the map is represented as metatiles. (23-24 16x16 tiles make up a 300ish pixel resolution.) My game ...
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36 views

SDL — What am I doing wrong with SDL_LockTexture()?

I'm trying to use SDL_LockTexture and SDL_UnlockTexture for direct access to pixels in SDL 2.0. When I try to set pixels, I never see anything happen. Here's my code: void *pixels; int pitch; ...
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1answer
85 views

SDL pixel access very slow

I'm using SDL and need to plot pixels one by one on the screen. When I do this, it's extremely slow. I followed the tutorial here: http://www.programmersranch.com/2014/02/sdl2-pixel-drawing.html ...
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2answers
137 views

Are SDL games trivially portable from Linux to Windows?

I have a small game made with SDL2 and I want to port it to Windows. Would I hav eto write a lot of #ifdefs to port it or will the very same code work on Windows and Linux? Or is it more complicated? ...
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48 views

Pixel buffers in SDL

I'm using SDL and c++ and trying to create a class to work on pixel basics. The buffer is a multidimensional char array. char buff[scW][scH]; The video mode is being set by a ...
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1answer
110 views

How do I implement a fixed delta time step with a SDL_Delay(15ms) precision

So I am using SDL2.0 for making a Game Engine. Where I am having a problem is using SDL_Delay(). SDL_Delay's minimum delay time is 15ms, I've tried everything, and my FPS is Stuck at 64 because of ...
3
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1answer
190 views

How can I optimize per-pixel drawing in SDL?

I've been messing around with C++ the last few days and I'm trying to figure out how to draw the screen pixel by pixel each frame. It sounded simple enough at first, but then I realized for loops ...
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0answers
30 views

Pseudo 3D questions in SDL/C++ [duplicate]

I'm going for a SNES mode 7 effect. From my understanding you do maths, to grab the current pixel from z values. Resulting from this math you take an image and then transcribe it into the screen for a ...
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1answer
68 views

How do I compile further libraries into my game? [closed]

This might be vague; I don't know how to search for this. How do I link a GUI framework (in my case, CEGUI) to a graphics framework (in my case, SDL)? I'm using a Mac. My mental model on how to add ...
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2answers
53 views

Kerning between glyphs using SDL2_ttf

I'm loading a number of characters (using SDL2_ttf) into a texture atlas to improve performance. The glyphs can be separately rendered correctly, however, how can you find the kerning distance ...
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1answer
123 views

Problem with 2D matrix transform og shapes

I have set myself onto the task of creating a class BaseObject, which represents a graphics object with an associated shape as the member variable shape, which is a pointer an object Polygon. I'll ...
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1answer
52 views

How do I destroy a SDL_Finger pointer?

Hello I'm using SDL with C++ and I got this code: void handleEvents() { SDL_Finger* finger = SDL_GetTouchFinger(SDL_GetTouchDevice(0), 0); } I do not know what SDL does inside the GetTouch ...
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1answer
100 views

How to handle pathfinding and path following with sprites the same size as the grid?

The game I am working on is currently using 32X32 collision boxes. I have implemented a working AI (A* - path finding method) which is based on the Grid Size. Lets say that I use that 16x16 grid , ...
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2answers
27 views

Question about where to put a method [closed]

I'm working on a tower defense game as a class project and i got it to a kinda working level(creep spawns, towers can shoot etc), but i have a problem with my classes. Currently the towers shoot but ...
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1answer
93 views

How to make a stereoscopic 3D Game with SDL for iOS

I was looking up google for an answer the whole night but didn't find anything. Yesterday I found some VR demos and games on the AppStore, with stereoscopig (dual rendered) screens. So you put your ...
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1answer
155 views

SDL_PollEvent very slow on SDL2, but works fine on SDL1.2

I have this simple app that displays a screen and handles the quit event: while( SDL_PollEvent( &e ) != 0 ) { //User requests quit if( e.type == SDL_QUIT ) { ...
3
votes
1answer
57 views

SDL2 jagged/staircase edges

I am using SDL2 and SDL2 Image to render png images. When I rotate the textures, they turn out very ugly, like this: This is the code responsible for the rotation and alpha mod. SDL_Rect srcRect; ...
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1answer
97 views

Calculate slope for linear interpolated movement

I want to move rectangles to their targets the "smooth" way with linear interpolation. I hope this is right. float slope(float x1, float x2, float y1, float y2) { return std::abs((y2 - y1)) / ...
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1answer
94 views

Problem with SLD/OpenGL

I've started to do sth. with SDL/openGL, but I haven't managed to get this tutorial running yet (http://www.sdltutorials.com/sdl-opengl-tutorial-basics). Since this tutorial, or most tutorials at ...
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2answers
6k views

How to implement SDL Button/Menu GUI with callbacks?

I have been reading Bjarne Stroustrup's Programming Principles and Practice Using C++ for a while now and am nearing the end of the book. I have to tried to make a very simple game using the SDL ...
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1answer
98 views

Reference keyboard keys as “justPressed”, “pressed”, and “justReleased” with SDL in C++

I'm teaching myself 3D graphics with OpenGL and SDL in C++. I'm at a point where I need to be able to query states of individual keys, like so: if (InputManager::justPressed(SDLK_UP)) {} if ...
1
vote
1answer
641 views

How to pick a 3D object with known mouse coordinates if the camera is rotated 60 degrees?

I am making a simple game engine for a simple RTS game and would like to be able to pick a cube and move it around with the mouse coordinates. The problem is that my camera is rotated 60 degrees just ...
1
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1answer
110 views

SDL2 Gamepad triggers trigger when disconnecting the pad

I'm using MonoGame and SDL2. I'm having a strange problem with the Gamepad. When I disconnect it during the game, before the disconnected event fires, the left and right triggers return values as if ...
0
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1answer
133 views

Rectangle collision in SDL2 partially allowing sliding C++ [closed]

I am working on a game in SDL2, in which the player needs to be able to slide along walls, but NOT go through them. I've read up on things like Quadtrees, and this stackoverflow question ...
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3answers
408 views

Can I create relative filepaths to images in an XCode SDL project?

Can I create relative filepaths to images in an XCode SDL project? I have to use absolute filepaths as it is, but it would be much easier if I could make the filepaths relative.
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0answers
116 views

Artifacts rendering high-poly procedural meshes with OpenGL

I am having some issues when rendering some procedural generated meshes. There are some really wierd artifacts when rendering high-poly count meshes (not that much actualy). I have been able to ...
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0answers
52 views

SDL_Mixer .xm file loop not working correctly [closed]

I am working on a little game in my spare time using C++ and SDL and I have encountered a problem with a .xm file playback. The music is supposed to have an intro of a couple patterns and then ...
1
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1answer
189 views

How can I perform a masked erase in SDL2?

I'm trying to implement some shadow/lighting effects in my 2D-project, and I've concluded that if there is an easy way to perform a masked erase on an SDL_Texture, it would make the drawing operations ...
0
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1answer
115 views

Memory-leak around SDL_FreeSurface

When I call my tile engine function, the amount of memory my program uses begins to spike at about 80 - 90 megabytes per second. The memory use continues to go up until the program crashes. The ...