Atlas - primitives.c
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[FILE BEGIN]
1/*
2 * This example creates an SDL window and renderer, and then draws some lines,
3 * rectangles and points to it every frame.
4 *
5 * This code is public domain. Feel free to use it for any purpose!
6 */
7
8#define SDL_MAIN_USE_CALLBACKS 1  /* use the callbacks instead of main() */
9#include <SDL3/SDL.h>
10#include <SDL3/SDL_main.h>
11
12/* We will use this renderer to draw into this window every frame. */
13static SDL_Window *window = NULL;
14static SDL_Renderer *renderer = NULL;
15static SDL_FPoint points[500];
16
17/* This function runs once at startup. */
18SDL_AppResult SDL_AppInit(void **appstate, int argc, char *argv[])
19{
20    int i;
21
22    SDL_SetAppMetadata("Example Renderer Primitives", "1.0", "com.example.renderer-primitives");
23
24    if (!SDL_Init(SDL_INIT_VIDEO)) {
25        SDL_Log("Couldn't initialize SDL: %s", SDL_GetError());
26        return SDL_APP_FAILURE;
27    }
28
29    if (!SDL_CreateWindowAndRenderer("examples/renderer/primitives", 640, 480, SDL_WINDOW_RESIZABLE, &window, &renderer)) {
30        SDL_Log("Couldn't create window/renderer: %s", SDL_GetError());
31        return SDL_APP_FAILURE;
32    }
33    SDL_SetRenderLogicalPresentation(renderer, 640, 480, SDL_LOGICAL_PRESENTATION_LETTERBOX);
34
35    /* set up some random points */
36    for (i = 0; i < SDL_arraysize(points); i++) {
37        points[i].x = (SDL_randf() * 440.0f) + 100.0f;
38        points[i].y = (SDL_randf() * 280.0f) + 100.0f;
39    }
40
41    return SDL_APP_CONTINUE;  /* carry on with the program! */
42}
43
44/* This function runs when a new event (mouse input, keypresses, etc) occurs. */
45SDL_AppResult SDL_AppEvent(void *appstate, SDL_Event *event)
46{
47    if (event->type == SDL_EVENT_QUIT) {
48        return SDL_APP_SUCCESS;  /* end the program, reporting success to the OS. */
49    }
50    return SDL_APP_CONTINUE;  /* carry on with the program! */
51}
52
53/* This function runs once per frame, and is the heart of the program. */
54SDL_AppResult SDL_AppIterate(void *appstate)
55{
56    SDL_FRect rect;
57
58    /* as you can see from this, rendering draws over whatever was drawn before it. */
59    SDL_SetRenderDrawColor(renderer, 33, 33, 33, SDL_ALPHA_OPAQUE);  /* dark gray, full alpha */
60    SDL_RenderClear(renderer);  /* start with a blank canvas. */
61
62    /* draw a filled rectangle in the middle of the canvas. */
63    SDL_SetRenderDrawColor(renderer, 0, 0, 255, SDL_ALPHA_OPAQUE);  /* blue, full alpha */
64    rect.x = rect.y = 100;
65    rect.w = 440;
66    rect.h = 280;
67    SDL_RenderFillRect(renderer, &rect);
68
69    /* draw some points across the canvas. */
70    SDL_SetRenderDrawColor(renderer, 255, 0, 0, SDL_ALPHA_OPAQUE);  /* red, full alpha */
71    SDL_RenderPoints(renderer, points, SDL_arraysize(points));
72
73    /* draw a unfilled rectangle in-set a little bit. */
74    SDL_SetRenderDrawColor(renderer, 0, 255, 0, SDL_ALPHA_OPAQUE);  /* green, full alpha */
75    rect.x += 30;
76    rect.y += 30;
77    rect.w -= 60;
78    rect.h -= 60;
79    SDL_RenderRect(renderer, &rect);
80
81    /* draw two lines in an X across the whole canvas. */
82    SDL_SetRenderDrawColor(renderer, 255, 255, 0, SDL_ALPHA_OPAQUE);  /* yellow, full alpha */
83    SDL_RenderLine(renderer, 0, 0, 640, 480);
84    SDL_RenderLine(renderer, 0, 480, 640, 0);
85
86    SDL_RenderPresent(renderer);  /* put it all on the screen! */
87
88    return SDL_APP_CONTINUE;  /* carry on with the program! */
89}
90
91/* This function runs once at shutdown. */
92void SDL_AppQuit(void *appstate, SDL_AppResult result)
93{
94    /* SDL will clean up the window/renderer for us. */
95}
96
97
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