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97 lines
3.4 KiB
C
97 lines
3.4 KiB
C
/*
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* This example creates an SDL window and renderer, and then draws some lines,
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* rectangles and points to it every frame.
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*
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* This code is public domain. Feel free to use it for any purpose!
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*/
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#define SDL_MAIN_USE_CALLBACKS 1 /* use the callbacks instead of main() */
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#include <SDL3/SDL.h>
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#include <SDL3/SDL_main.h>
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/* We will use this renderer to draw into this window every frame. */
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static SDL_Window *window = NULL;
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static SDL_Renderer *renderer = NULL;
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static SDL_FPoint points[500];
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/* This function runs once at startup. */
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SDL_AppResult SDL_AppInit(void **appstate, int argc, char *argv[])
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{
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int i;
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SDL_SetAppMetadata("Example Renderer Primitives", "1.0", "com.example.renderer-primitives");
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if (!SDL_Init(SDL_INIT_VIDEO)) {
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SDL_Log("Couldn't initialize SDL: %s", SDL_GetError());
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return SDL_APP_FAILURE;
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}
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if (!SDL_CreateWindowAndRenderer("examples/renderer/primitives", 640, 480, SDL_WINDOW_RESIZABLE, &window, &renderer)) {
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SDL_Log("Couldn't create window/renderer: %s", SDL_GetError());
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return SDL_APP_FAILURE;
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}
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SDL_SetRenderLogicalPresentation(renderer, 640, 480, SDL_LOGICAL_PRESENTATION_LETTERBOX);
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/* set up some random points */
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for (i = 0; i < SDL_arraysize(points); i++) {
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points[i].x = (SDL_randf() * 440.0f) + 100.0f;
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points[i].y = (SDL_randf() * 280.0f) + 100.0f;
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}
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return SDL_APP_CONTINUE; /* carry on with the program! */
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}
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/* This function runs when a new event (mouse input, keypresses, etc) occurs. */
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SDL_AppResult SDL_AppEvent(void *appstate, SDL_Event *event)
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{
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if (event->type == SDL_EVENT_QUIT) {
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return SDL_APP_SUCCESS; /* end the program, reporting success to the OS. */
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}
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return SDL_APP_CONTINUE; /* carry on with the program! */
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}
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/* This function runs once per frame, and is the heart of the program. */
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SDL_AppResult SDL_AppIterate(void *appstate)
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{
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SDL_FRect rect;
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/* as you can see from this, rendering draws over whatever was drawn before it. */
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SDL_SetRenderDrawColor(renderer, 33, 33, 33, SDL_ALPHA_OPAQUE); /* dark gray, full alpha */
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SDL_RenderClear(renderer); /* start with a blank canvas. */
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/* draw a filled rectangle in the middle of the canvas. */
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SDL_SetRenderDrawColor(renderer, 0, 0, 255, SDL_ALPHA_OPAQUE); /* blue, full alpha */
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rect.x = rect.y = 100;
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rect.w = 440;
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rect.h = 280;
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SDL_RenderFillRect(renderer, &rect);
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/* draw some points across the canvas. */
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SDL_SetRenderDrawColor(renderer, 255, 0, 0, SDL_ALPHA_OPAQUE); /* red, full alpha */
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SDL_RenderPoints(renderer, points, SDL_arraysize(points));
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/* draw a unfilled rectangle in-set a little bit. */
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SDL_SetRenderDrawColor(renderer, 0, 255, 0, SDL_ALPHA_OPAQUE); /* green, full alpha */
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rect.x += 30;
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rect.y += 30;
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rect.w -= 60;
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rect.h -= 60;
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SDL_RenderRect(renderer, &rect);
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/* draw two lines in an X across the whole canvas. */
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SDL_SetRenderDrawColor(renderer, 255, 255, 0, SDL_ALPHA_OPAQUE); /* yellow, full alpha */
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SDL_RenderLine(renderer, 0, 0, 640, 480);
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SDL_RenderLine(renderer, 0, 480, 640, 0);
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SDL_RenderPresent(renderer); /* put it all on the screen! */
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return SDL_APP_CONTINUE; /* carry on with the program! */
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}
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/* This function runs once at shutdown. */
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void SDL_AppQuit(void *appstate, SDL_AppResult result)
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{
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/* SDL will clean up the window/renderer for us. */
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}
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