examples: Added renderer/primitives example.

examples/CMakeLists.txt

@@ -177,6 +177,7 @@ macro(add_sdl_example_executable TARGET)
 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)
 
 
 if(PSP)

examples/renderer/02-primitives/renderer-primitives.c

@@ -0,0 +1,89 @@
+/*
+ * This example code creates an SDL window and renderer, and then draws a few
+ * lines and rectangles 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;
+static SDL_FPoint points[500];
+
+/* This function runs once at startup. */
+int SDL_AppInit(void **appstate, int argc, char *argv[])
+{
+    int i;
+
+    if (SDL_CreateWindowAndRenderer("examples/renderer/clear", 640, 480, 0, &window, &renderer) == -1) {
+        SDL_ShowSimpleMessageBox(SDL_MESSAGEBOX_ERROR, "Couldn't create window/renderer!", SDL_GetError(), NULL);
+        return SDL_APP_FAILURE;
+    }
+
+    /* set up some random points */
+    SDL_srand(0);  /* seed the random number generator with current time */
+    for (i = 0; i < SDL_arraysize(points); i++) {
+        points[i].x = (SDL_randf() * 440.0f) + 100.0f;
+        points[i].y = (SDL_randf() * 280.0f) + 100.0f;
+    }
+
+    return SDL_APP_CONTINUE;  /* carry on with the program! */
+}
+
+/* This function runs when a new event (mouse input, keypresses, etc) occurs. */
+int SDL_AppEvent(void *appstate, const 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. */
+int SDL_AppIterate(void *appstate)
+{
+    SDL_FRect rect;
+
+    /* 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. */
+
+    /* draw a filled rectangle in the middle of the canvas. */
+    SDL_SetRenderDrawColor(renderer, 0, 0, 255, 255);  /* blue, full alpha */
+    rect.x = rect.y = 100;
+    rect.w = 440;
+    rect.h = 280;
+    SDL_RenderFillRect(renderer, &rect);
+
+    /* draw a unfilled rectangle in-set a little bit. */
+    SDL_SetRenderDrawColor(renderer, 0, 255, 0, 255);  /* green, full alpha */
+    rect.x += 30;
+    rect.y += 30;
+    rect.w -= 60;
+    rect.h -= 60;
+    SDL_RenderRect(renderer, &rect);
+
+    /* draw two lines in an X across the whole canvas. */
+    SDL_SetRenderDrawColor(renderer, 255, 255, 0, 255);  /* yellow, full alpha */
+    SDL_RenderLine(renderer, 0, 0, 640, 480);
+    SDL_RenderLine(renderer, 0, 480, 640, 0);
+
+    /* draw some points across the canvas. */
+    SDL_SetRenderDrawColor(renderer, 255, 0, 0, 255);  /* red, full alpha */
+    SDL_RenderPoints(renderer, points, SDL_arraysize(points));
+
+    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. */
+}
+

examples/template.c

@@ -35,6 +35,7 @@ int SDL_AppEvent(void *appstate, const SDL_Event *event)
 /* This function runs once per frame, and is the heart of the program. */
 int SDL_AppIterate(void *appstate)
 {
+    return SDL_APP_CONTINUE;  /* carry on with the program! */
 }
 
 /* This function runs once at shutdown. */