From 4e3e4f9aabf30fe60e3b0ef56efe100eef302b06 Mon Sep 17 00:00:00 2001
From: Josh Lyon <josh@lyonlab.org>
Date: Tue, 12 Aug 2025 20:02:48 -0600
Subject: [PATCH] rendering rectangles

---
 src/main.cpp | 65 +++++++++++++++++++++++++++++++---------------------
 1 file changed, 39 insertions(+), 26 deletions(-)

diff --git a/src/main.cpp b/src/main.cpp
index 2cf8aa8..418ff3b 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -9,8 +9,11 @@
   including commercial applications, and to alter it and redistribute it
   freely.
 */
+#include <SDL3/SDL_rect.h>
+#include <SDL3/SDL_render.h>
 #include <string>
 #define SDL_MAIN_USE_CALLBACKS 1  /* use the callbacks instead of main() */
+
 #include <SDL3/SDL.h>
 #include <SDL3/SDL_main.h>
 
@@ -20,46 +23,56 @@ static SDL_Renderer *renderer = nullptr;
 /* This function runs once at startup. */
 SDL_AppResult SDL_AppInit(void **appstate, int argc, char *argv[])
 {
-    /* Create the window */
-    if (!SDL_CreateWindowAndRenderer("Hello World", 800, 600, SDL_WINDOW_FULLSCREEN, &window, &renderer)) {
-        SDL_Log("Couldn't create window and renderer: %s", SDL_GetError());
-        return SDL_APP_FAILURE;
-    }
-    return SDL_APP_CONTINUE;
+  /* Create the window */
+  if (!SDL_CreateWindowAndRenderer("Hello World", 800, 600, SDL_WINDOW_FULLSCREEN, &window, &renderer)) {
+    SDL_Log("Couldn't create window and renderer: %s", SDL_GetError());
+    return SDL_APP_FAILURE;
+  }
+  return SDL_APP_CONTINUE;
 }
 
 /* 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_KEY_DOWN ||
-        event->type == SDL_EVENT_QUIT) {
-        return SDL_APP_SUCCESS;  /* end the program, reporting success to the OS. */
-    }
-    return SDL_APP_CONTINUE;
+  if (event->type == SDL_EVENT_KEY_DOWN ||
+    event->type == SDL_EVENT_QUIT) {
+    return SDL_APP_SUCCESS;  /* end the program, reporting success to the OS. */
+  }
+  return SDL_APP_CONTINUE;
 }
 
 /* This function runs once per frame, and is the heart of the program. */
 SDL_AppResult SDL_AppIterate(void *appstate)
 {
   std::string message("Hello World!");
-    int w = 0, h = 0;
-    float x, y;
-    const float scale = 4.0f;
+  int w = 0, h = 0;
+  float x, y;
+  const float scale = 4.0f;
 
-    /* Center the message and scale it up */
-    SDL_GetRenderOutputSize(renderer, &w, &h);
-    SDL_SetRenderScale(renderer, scale, scale);
-    x = ((w / scale) - SDL_DEBUG_TEXT_FONT_CHARACTER_SIZE * message.length()) / 2;
-    y = ((h / scale) - SDL_DEBUG_TEXT_FONT_CHARACTER_SIZE) / 2;
+  /* Center the message and scale it up */
+  SDL_GetRenderOutputSize(renderer, &w, &h);
+  SDL_SetRenderScale(renderer, scale, scale);
+  x = ((w / scale) - SDL_DEBUG_TEXT_FONT_CHARACTER_SIZE * message.length()) / 2;
+  y = ((h / scale) - SDL_DEBUG_TEXT_FONT_CHARACTER_SIZE) / 2;
 
-    /* Draw the message */
-    SDL_SetRenderDrawColor(renderer, 0, 0, 0, 255);
-    SDL_RenderClear(renderer);
-    SDL_SetRenderDrawColor(renderer, 255, 255, 255, 255);
-    SDL_RenderDebugText(renderer, x, y, message.c_str());
-    SDL_RenderPresent(renderer);
+  SDL_FRect rect {
+    .x = 30,
+    .y = 30,
+    .w = 100,
+    .h = 100
+  };
 
-    return SDL_APP_CONTINUE;
+
+  /* Draw the message */
+  SDL_SetRenderDrawColor(renderer, 0, 0, 200, 255);
+  SDL_RenderClear(renderer);
+  SDL_SetRenderDrawColor(renderer, 255, 0, 0, 255);
+  SDL_RenderFillRect(renderer, &rect);
+  SDL_SetRenderDrawColor(renderer, 255, 255, 255, 255);
+  SDL_RenderDebugText(renderer, x, y, message.c_str());
+  SDL_RenderPresent(renderer);
+
+  return SDL_APP_CONTINUE;
 }
 
 /* This function runs once at shutdown. */