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Diffstat (limited to 'src/contrib/SDL-3.2.20/examples/renderer/04-points/points.c')
-rw-r--r-- | src/contrib/SDL-3.2.20/examples/renderer/04-points/points.c | 118 |
1 files changed, 118 insertions, 0 deletions
diff --git a/src/contrib/SDL-3.2.20/examples/renderer/04-points/points.c b/src/contrib/SDL-3.2.20/examples/renderer/04-points/points.c new file mode 100644 index 0000000..b7b5c21 --- /dev/null +++ b/src/contrib/SDL-3.2.20/examples/renderer/04-points/points.c | |||
@@ -0,0 +1,118 @@ | |||
1 | /* | ||
2 | * This example creates an SDL window and renderer, and then draws some points | ||
3 | * 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. */ | ||
13 | static SDL_Window *window = NULL; | ||
14 | static SDL_Renderer *renderer = NULL; | ||
15 | static Uint64 last_time = 0; | ||
16 | |||
17 | #define WINDOW_WIDTH 640 | ||
18 | #define WINDOW_HEIGHT 480 | ||
19 | |||
20 | #define NUM_POINTS 500 | ||
21 | #define MIN_PIXELS_PER_SECOND 30 /* move at least this many pixels per second. */ | ||
22 | #define MAX_PIXELS_PER_SECOND 60 /* move this many pixels per second at most. */ | ||
23 | |||
24 | /* (track everything as parallel arrays instead of a array of structs, | ||
25 | so we can pass the coordinates to the renderer in a single function call.) */ | ||
26 | |||
27 | /* Points are plotted as a set of X and Y coordinates. | ||
28 | (0, 0) is the top left of the window, and larger numbers go down | ||
29 | and to the right. This isn't how geometry works, but this is pretty | ||
30 | standard in 2D graphics. */ | ||
31 | static SDL_FPoint points[NUM_POINTS]; | ||
32 | static float point_speeds[NUM_POINTS]; | ||
33 | |||
34 | /* This function runs once at startup. */ | ||
35 | SDL_AppResult SDL_AppInit(void **appstate, int argc, char *argv[]) | ||
36 | { | ||
37 | int i; | ||
38 | |||
39 | SDL_SetAppMetadata("Example Renderer Points", "1.0", "com.example.renderer-points"); | ||
40 | |||
41 | if (!SDL_Init(SDL_INIT_VIDEO)) { | ||
42 | SDL_Log("Couldn't initialize SDL: %s", SDL_GetError()); | ||
43 | return SDL_APP_FAILURE; | ||
44 | } | ||
45 | |||
46 | if (!SDL_CreateWindowAndRenderer("examples/renderer/points", WINDOW_WIDTH, WINDOW_HEIGHT, 0, &window, &renderer)) { | ||
47 | SDL_Log("Couldn't create window/renderer: %s", SDL_GetError()); | ||
48 | return SDL_APP_FAILURE; | ||
49 | } | ||
50 | |||
51 | /* set up the data for a bunch of points. */ | ||
52 | for (i = 0; i < SDL_arraysize(points); i++) { | ||
53 | points[i].x = SDL_randf() * ((float) WINDOW_WIDTH); | ||
54 | points[i].y = SDL_randf() * ((float) WINDOW_HEIGHT); | ||
55 | point_speeds[i] = MIN_PIXELS_PER_SECOND + (SDL_randf() * (MAX_PIXELS_PER_SECOND - MIN_PIXELS_PER_SECOND)); | ||
56 | } | ||
57 | |||
58 | last_time = SDL_GetTicks(); | ||
59 | |||
60 | return SDL_APP_CONTINUE; /* carry on with the program! */ | ||
61 | } | ||
62 | |||
63 | /* This function runs when a new event (mouse input, keypresses, etc) occurs. */ | ||
64 | SDL_AppResult SDL_AppEvent(void *appstate, SDL_Event *event) | ||
65 | { | ||
66 | if (event->type == SDL_EVENT_QUIT) { | ||
67 | return SDL_APP_SUCCESS; /* end the program, reporting success to the OS. */ | ||
68 | } | ||
69 | return SDL_APP_CONTINUE; /* carry on with the program! */ | ||
70 | } | ||
71 | |||
72 | /* This function runs once per frame, and is the heart of the program. */ | ||
73 | SDL_AppResult SDL_AppIterate(void *appstate) | ||
74 | { | ||
75 | const Uint64 now = SDL_GetTicks(); | ||
76 | const float elapsed = ((float) (now - last_time)) / 1000.0f; /* seconds since last iteration */ | ||
77 | int i; | ||
78 | |||
79 | /* let's move all our points a little for a new frame. */ | ||
80 | for (i = 0; i < SDL_arraysize(points); i++) { | ||
81 | const float distance = elapsed * point_speeds[i]; | ||
82 | points[i].x += distance; | ||
83 | points[i].y += distance; | ||
84 | if ((points[i].x >= WINDOW_WIDTH) || (points[i].y >= WINDOW_HEIGHT)) { | ||
85 | /* off the screen; restart it elsewhere! */ | ||
86 | if (SDL_rand(2)) { | ||
87 | points[i].x = SDL_randf() * ((float) WINDOW_WIDTH); | ||
88 | points[i].y = 0.0f; | ||
89 | } else { | ||
90 | points[i].x = 0.0f; | ||
91 | points[i].y = SDL_randf() * ((float) WINDOW_HEIGHT); | ||
92 | } | ||
93 | point_speeds[i] = MIN_PIXELS_PER_SECOND + (SDL_randf() * (MAX_PIXELS_PER_SECOND - MIN_PIXELS_PER_SECOND)); | ||
94 | } | ||
95 | } | ||
96 | |||
97 | last_time = now; | ||
98 | |||
99 | /* as you can see from this, rendering draws over whatever was drawn before it. */ | ||
100 | SDL_SetRenderDrawColor(renderer, 0, 0, 0, SDL_ALPHA_OPAQUE); /* black, full alpha */ | ||
101 | SDL_RenderClear(renderer); /* start with a blank canvas. */ | ||
102 | SDL_SetRenderDrawColor(renderer, 255, 255, 255, SDL_ALPHA_OPAQUE); /* white, full alpha */ | ||
103 | SDL_RenderPoints(renderer, points, SDL_arraysize(points)); /* draw all the points! */ | ||
104 | |||
105 | /* You can also draw single points with SDL_RenderPoint(), but it's | ||
106 | cheaper (sometimes significantly so) to do them all at once. */ | ||
107 | |||
108 | SDL_RenderPresent(renderer); /* put it all on the screen! */ | ||
109 | |||
110 | return SDL_APP_CONTINUE; /* carry on with the program! */ | ||
111 | } | ||
112 | |||
113 | /* This function runs once at shutdown. */ | ||
114 | void SDL_AppQuit(void *appstate, SDL_AppResult result) | ||
115 | { | ||
116 | /* SDL will clean up the window/renderer for us. */ | ||
117 | } | ||
118 | |||