mirror of https://github.com/libsdl-org/SDL
113 lines
4.2 KiB
C
113 lines
4.2 KiB
C
/*
|
|
* This example code reads frames from a camera and draws it to the screen.
|
|
*
|
|
* This is a very simple approach that is often Good Enough. You can get
|
|
* fancier with this: multiple cameras, front/back facing cameras on phones,
|
|
* color spaces, choosing formats and framerates...this just requests
|
|
* _anything_ and goes with what it is handed.
|
|
*
|
|
* This code is public domain. Feel free to use it for any purpose!
|
|
*/
|
|
|
|
#define SDL_MAIN_USE_CALLBACKS 1 /* use the callbacks instead of main() */
|
|
#include <SDL3/SDL.h>
|
|
#include <SDL3/SDL_main.h>
|
|
|
|
/* We will use this renderer to draw into this window every frame. */
|
|
static SDL_Window *window = NULL;
|
|
static SDL_Renderer *renderer = NULL;
|
|
static SDL_Camera *camera = NULL;
|
|
static SDL_Texture *texture = NULL;
|
|
|
|
|
|
/* This function runs once at startup. */
|
|
SDL_AppResult SDL_AppInit(void **appstate, int argc, char *argv[])
|
|
{
|
|
SDL_CameraID *devices = NULL;
|
|
int devcount = 0;
|
|
|
|
if (!SDL_Init(SDL_INIT_VIDEO | SDL_INIT_CAMERA)) {
|
|
SDL_ShowSimpleMessageBox(SDL_MESSAGEBOX_ERROR, "Couldn't initialize SDL!", SDL_GetError(), NULL);
|
|
return SDL_APP_FAILURE;
|
|
}
|
|
|
|
if (!SDL_CreateWindowAndRenderer("examples/camera/read-and-draw", 640, 480, 0, &window, &renderer)) {
|
|
SDL_ShowSimpleMessageBox(SDL_MESSAGEBOX_ERROR, "Couldn't create window/renderer!", SDL_GetError(), NULL);
|
|
return SDL_APP_FAILURE;
|
|
}
|
|
|
|
devices = SDL_GetCameras(&devcount);
|
|
if (devices == NULL) {
|
|
SDL_ShowSimpleMessageBox(SDL_MESSAGEBOX_ERROR, "Couldn't enumerate camera devices!", SDL_GetError(), window);
|
|
return SDL_APP_FAILURE;
|
|
} else if (devcount == 0) {
|
|
SDL_ShowSimpleMessageBox(SDL_MESSAGEBOX_ERROR, "Couldn't find any camera devices!", "Please connect a camera and try again.", window);
|
|
return SDL_APP_FAILURE;
|
|
}
|
|
|
|
camera = SDL_OpenCamera(devices[0], NULL); // just take the first thing we see in any format it wants.
|
|
SDL_free(devices);
|
|
if (camera == NULL) {
|
|
SDL_ShowSimpleMessageBox(SDL_MESSAGEBOX_ERROR, "Couldn't open camera!", SDL_GetError(), window);
|
|
return SDL_APP_FAILURE;
|
|
}
|
|
|
|
return SDL_APP_CONTINUE; /* carry on with the program! */
|
|
}
|
|
|
|
/* This function runs when a new event (mouse input, keypresses, etc) occurs. */
|
|
SDL_AppResult SDL_AppEvent(void *appstate, SDL_Event *event)
|
|
{
|
|
if (event->type == SDL_EVENT_QUIT) {
|
|
return SDL_APP_SUCCESS; /* end the program, reporting success to the OS. */
|
|
} else if (event->type == SDL_EVENT_CAMERA_DEVICE_APPROVED) {
|
|
SDL_Log("Camera use approved by user!");
|
|
} else if (event->type == SDL_EVENT_CAMERA_DEVICE_DENIED) {
|
|
SDL_Log("Camera use denied by user!");
|
|
SDL_ShowSimpleMessageBox(SDL_MESSAGEBOX_ERROR, "Camera permission denied!", "User denied access to the camera!", window);
|
|
return SDL_APP_FAILURE;
|
|
}
|
|
return SDL_APP_CONTINUE; /* carry on with the program! */
|
|
}
|
|
|
|
/* This function runs once per frame, and is the heart of the program. */
|
|
SDL_AppResult SDL_AppIterate(void *appstate)
|
|
{
|
|
Uint64 timestampNS = 0;
|
|
SDL_Surface *frame = SDL_AcquireCameraFrame(camera, ×tampNS);
|
|
|
|
if (frame != NULL) {
|
|
/* Some platforms (like Emscripten) don't know _what_ the camera offers
|
|
until the user gives permission, so we build the texture and resize
|
|
the window when we get a first frame from the camera. */
|
|
if (!texture) {
|
|
SDL_SetWindowSize(window, frame->w, frame->h); /* Resize the window to match */
|
|
texture = SDL_CreateTexture(renderer, frame->format, SDL_TEXTUREACCESS_STREAMING, frame->w, frame->h);
|
|
}
|
|
|
|
if (texture) {
|
|
SDL_UpdateTexture(texture, NULL, frame->pixels, frame->pitch);
|
|
}
|
|
|
|
SDL_ReleaseCameraFrame(camera, frame);
|
|
}
|
|
|
|
SDL_SetRenderDrawColor(renderer, 0x99, 0x99, 0x99, 255);
|
|
SDL_RenderClear(renderer);
|
|
if (texture) { /* draw the latest camera frame, if available. */
|
|
SDL_RenderTexture(renderer, texture, NULL, NULL);
|
|
}
|
|
SDL_RenderPresent(renderer);
|
|
|
|
return SDL_APP_CONTINUE; /* carry on with the program! */
|
|
}
|
|
|
|
/* This function runs once at shutdown. */
|
|
void SDL_AppQuit(void *appstate)
|
|
{
|
|
SDL_CloseCamera(camera);
|
|
SDL_DestroyTexture(texture);
|
|
/* SDL will clean up the window/renderer for us. */
|
|
}
|
|
|