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examples: added renderer/03-lines

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This commit is contained in:
Ryan C. Gordon
2024-09-19 12:15:42 -04:00
parent 6771a6020d
commit 1b266ec13d
3 changed files with 72 additions and 0 deletions
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1
examples/CMakeLists.txt
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@@ -122,6 +122,7 @@ endmacro()
add_sdl_example_executable(renderer-clear SOURCES renderer/01-clear/renderer-clear.c)
add_sdl_example_executable(renderer-primitives SOURCES renderer/02-primitives/renderer-primitives.c)
add_sdl_example_executable(renderer-lines SOURCES renderer/03-lines/renderer-lines.c)
add_sdl_example_executable(audio-simple-playback SOURCES audio/01-simple-playback/simple-playback.c)
add_sdl_example_executable(audio-simple-playback-callback SOURCES audio/02-simple-playback-callback/simple-playback-callback.c)
add_sdl_example_executable(audio-load-wav SOURCES audio/03-load-wav/load-wav.c DATAFILES ${CMAKE_CURRENT_SOURCE_DIR}/../test/sample.wav)

3
examples/renderer/03-lines/README.txt Normal file
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@@ -0,0 +1,3 @@
This example creates an SDL window and renderer, and then draws a giant
pile of lines, in random colors, every frame.

68
examples/renderer/03-lines/renderer-lines.c Normal file
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@@ -0,0 +1,68 @@
/*
* This example creates an SDL window and renderer, and then draws some lines,
* rectangles and points to it every frame.
*
* 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;
/* This function runs once at startup. */
SDL_AppResult SDL_AppInit(void **appstate, int argc, char *argv[])
{
if (!SDL_Init(SDL_INIT_VIDEO)) {
SDL_ShowSimpleMessageBox(SDL_MESSAGEBOX_ERROR, "Couldn't initialize SDL!", SDL_GetError(), NULL);
return SDL_APP_FAILURE;
}
if (!SDL_CreateWindowAndRenderer("examples/renderer/lines", 640, 480, 0, &window, &renderer)) {
SDL_ShowSimpleMessageBox(SDL_MESSAGEBOX_ERROR, "Couldn't create window/renderer!", SDL_GetError(), NULL);
return SDL_APP_FAILURE;
}
SDL_srand(0); /* seed the random number generator */
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. */
}
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)
{
const int num_lines = 5000;
int i;
/* as you can see from this, rendering draws over whatever was drawn before it. */
SDL_SetRenderDrawColor(renderer, 0, 0, 0, 255); /* black, full alpha */
SDL_RenderClear(renderer); /* start with a blank canvas. */
for (i = 0; i < num_lines; i++) {
SDL_SetRenderDrawColor(renderer, SDL_rand(256), SDL_rand(256), SDL_rand(256), 255);
SDL_RenderLine(renderer, SDL_rand(640), SDL_rand(480), SDL_rand(640), SDL_rand(480));
}
SDL_RenderPresent(renderer); /* put it all on the screen! */
return SDL_APP_CONTINUE; /* carry on with the program! */
}
/* This function runs once at shutdown. */
void SDL_AppQuit(void *appstate)
{
/* SDL will clean up the window/renderer for us. */
}