sdl-2

问题 I'm trying to open a window with SDL2 in visual studio 2015. I've set a .bmp image in my code to display to the screen in a window, but when I run my code the program returns 0 and closes without a window. The .bmp image is in the project folder. How do you display the window? #include <SDL.h> #include <iostream> int main(int argc, char* args[]) { SDL_Window *window = nullptr; SDL_Surface *windowSurface = nullptr; SDL_Surface *imageSurface = nullptr; if (SDL_Init(SDL_INIT_VIDEO) < 0) std:

问题 I used CMake and Code::Blocks to build SDL2 from source, and attempted to link my own project source to the following static libraries: libSDL2.a libSDL2main.a OpenGL32.lib These three libraries are contained within the directory known as %libdir% (I'm using Batch for the command). I obtained libSDL2 and libSDL2main from the Code::Blocks build. I obtained OpenGL32 from my Windows directory, although I found it long ago so I am unable to recall the exact location. I used the following command:

问题 I program currently something with SDL2. All works fine, but I have a problem with the SDL_GetTicks() method. Normally it should return the total application time in milliseconds, but it always returns most of the time the value 0 and sometimes the value 1. I initialized SDL with SDL_INIT_EVERYTHING flag. The problem with the following code is the loop is too fast, so the delta time is smaller than 1 ms. Is there a method to achieve a higher precision? #include "Application.hpp" void

问题 I program currently something with SDL2. All works fine, but I have a problem with the SDL_GetTicks() method. Normally it should return the total application time in milliseconds, but it always returns most of the time the value 0 and sometimes the value 1. I initialized SDL with SDL_INIT_EVERYTHING flag. The problem with the following code is the loop is too fast, so the delta time is smaller than 1 ms. Is there a method to achieve a higher precision? #include "Application.hpp" void

问题 I'm currently writing a simple program using SDL2 where you can drag some shapes (square, circle, triangle, etc) into a canvas and rotate them and move them around. Each shape is represented visually by a SDL texture that is created from a PNG file (using the IMG_LoadTexture function from the SDL_image library). The thing is that I would like to know whether a certain pixel from the texture is transparent, so that when someone clicks on the image I could determine if I have to do some action

问题 Question is simple so, no codes! If someone knows Box2D and SDL2, then, please tell me how to wrap SDL_Rect with b2body. Ofcourse, it requires to know the conversion of metre to pixel and vice versa. This is because Box2D measures distance in metres. Can you give me a simple expression or function to convert metres(of Box2D) to pixels or pixels to metres(of Box2D)? 回答1: Can you give me a simple expression or function to convert metres(of Box2D) to pixels or pixels to metres(of Box2D)?

问题 Previously in my main loop of the game, the time was managed at 60 FPS and the respective Delay for the time delay. The Sprite sequence was animated as follows: <pre> if(++ciclos > 10){ siguienteSprite++; ciclos = 0; } </pre> Given that I am using Smooth Motion with DeltaTime, therefore I have eliminated Delay from the Main Cycle; Making this the sprites cycles of the animation are faster, and not only this, but also the time between each sequence varies. Someone could give me a hand, only

问题 I am programming a raycasting game using SDL2. When drawing the floor, I need to call SDL_RenderCopy pixelwise. This leads to a bottleneck which drops the framerate below 10 fps. I am looking for performance boosts but can't seem to find some. Here's a rough overview of the performance drop: int main() { while(true) { for(x=0; x<800; x++) { for(y=0; y<600; y++) { SDL_Rect src = { 0, 0, 1, 1 }; SDL_Rect dst = { x, y, 1, 1 }; SDL_RenderCopy(ren, tx, &src, &dst); // this drops the framerate

问题 I'm using pixel-perfect source images and SDL2 to make a program. When set to fullscreen, I'd like it to use the native resolution (the SDL_WINDOW_FULLSCREEN_DESKTOP flag) but only between a certain minimum resolution and a reasonable maximum one, after which it will stretch from the largest legal resolution. The problem is that I can only find references to the program's own window or program size on the SDL2 documentation. Is there any function in SDL from which I could retrieve the screen

问题 Hi I would like to know if it is possible to simply take a screenshot with SDL2. I tried SDL_GetWindowSurface but I get an error saying: No hardware accelerated renderers available. I took the code from here. Another solution I thought about is converting a texture to a surface but I didn't manage to do so... Do you have any solution? 回答1: It seems like you are mixing the rendering systems. That method will only work in the context of software rendering. For hardware rendering you should use