From ffcf372d275243826481d7889c7cebf656148c5e Mon Sep 17 00:00:00 2001
From: "Ryan C. Gordon" <[EMAIL REDACTED]>
Date: Sat, 21 Sep 2024 20:52:32 -0400
Subject: [PATCH] examples: Added renderer/08-rotating-textures
---
examples/CMakeLists.txt | 1 +
.../renderer/08-rotating-textures/README.txt | 3 +
.../renderer-rotating-textures.c | 110 ++++++++++++++++++
3 files changed, 114 insertions(+)
create mode 100644 examples/renderer/08-rotating-textures/README.txt
create mode 100644 examples/renderer/08-rotating-textures/renderer-rotating-textures.c
diff --git a/examples/CMakeLists.txt b/examples/CMakeLists.txt
index 78bbd78d09428..e728e116c97c2 100644
--- a/examples/CMakeLists.txt
+++ b/examples/CMakeLists.txt
@@ -127,6 +127,7 @@ add_sdl_example_executable(renderer-points SOURCES renderer/04-points/renderer-p
add_sdl_example_executable(renderer-rectangles SOURCES renderer/05-rectangles/renderer-rectangles.c)
add_sdl_example_executable(renderer-textures SOURCES renderer/06-textures/renderer-textures.c)
add_sdl_example_executable(renderer-streaming-textures SOURCES renderer/07-streaming-textures/renderer-streaming-textures.c)
+add_sdl_example_executable(renderer-rotating-textures SOURCES renderer/08-rotating-textures/renderer-rotating-textures.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)
diff --git a/examples/renderer/08-rotating-textures/README.txt b/examples/renderer/08-rotating-textures/README.txt
new file mode 100644
index 0000000000000..4ae46bc21c8f4
--- /dev/null
+++ b/examples/renderer/08-rotating-textures/README.txt
@@ -0,0 +1,3 @@
+This example creates an SDL window and renderer, loads a texture from a .bmp
+file, and then draws it, rotating around the center of the screen.
+
diff --git a/examples/renderer/08-rotating-textures/renderer-rotating-textures.c b/examples/renderer/08-rotating-textures/renderer-rotating-textures.c
new file mode 100644
index 0000000000000..850527bc9a336
--- /dev/null
+++ b/examples/renderer/08-rotating-textures/renderer-rotating-textures.c
@@ -0,0 +1,110 @@
+/*
+ * This example creates an SDL window and renderer, and then draws some
+ * rotated textures 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_Texture *texture = NULL;
+static int texture_width = 0;
+static int texture_height = 0;
+
+#define WINDOW_WIDTH 640
+#define WINDOW_HEIGHT 480
+
+/* This function runs once at startup. */
+SDL_AppResult SDL_AppInit(void **appstate, int argc, char *argv[])
+{
+ SDL_Surface *surface = NULL;
+ char *bmp_path = NULL;
+
+ 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/rotating-textures", WINDOW_WIDTH, WINDOW_HEIGHT, 0, &window, &renderer)) {
+ SDL_ShowSimpleMessageBox(SDL_MESSAGEBOX_ERROR, "Couldn't create window/renderer!", SDL_GetError(), NULL);
+ return SDL_APP_FAILURE;
+ }
+
+ /* Textures are pixel data that we upload to the video hardware for fast drawing. Lots of 2D
+ engines refer to these as "sprites." We'll do a static texture (upload once, draw many
+ times) with data from a bitmap file. */
+
+ /* SDL_Surface is pixel data the CPU can access. SDL_Texture is pixel data the GPU can access.
+ Load a .bmp into a surface, move it to a texture from there. */
+ SDL_asprintf(&bmp_path, "%ssample.bmp", SDL_GetBasePath()); /* allocate a string of the full file path */
+ surface = SDL_LoadBMP(bmp_path);
+ if (!surface) {
+ SDL_ShowSimpleMessageBox(SDL_MESSAGEBOX_ERROR, "Couldn't load bitmap!", SDL_GetError(), NULL);
+ return SDL_APP_FAILURE;
+ }
+
+ SDL_free(bmp_path); /* done with this, the file is loaded. */
+
+ texture_width = surface->w;
+ texture_height = surface->h;
+
+ texture = SDL_CreateTextureFromSurface(renderer, surface);
+ if (!texture) {
+ SDL_ShowSimpleMessageBox(SDL_MESSAGEBOX_ERROR, "Couldn't create static texture!", SDL_GetError(), NULL);
+ return SDL_APP_FAILURE;
+ }
+
+ SDL_DestroySurface(surface); /* done with this, the texture has a copy of the pixels now. */
+
+ 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)
+{
+ SDL_FPoint center;
+ SDL_FRect dst_rect;
+ const Uint64 now = SDL_GetTicks();
+
+ /* we'll have a texture rotate around over 2 seconds (2000 milliseconds). 360 degrees in a circle! */
+ const float rotation = (((float) ((int) (now % 2000))) / 2000.0f) * 360.0f;
+
+ /* 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. */
+
+ /* Center this one, and draw it with some rotation so it spins! */
+ dst_rect.x = ((float) (WINDOW_WIDTH - texture_width)) / 2.0f;
+ dst_rect.y = ((float) (WINDOW_HEIGHT - texture_height)) / 2.0f;
+ dst_rect.w = (float) texture_width;
+ dst_rect.h = (float) texture_height;
+ /* rotate it around the center of the texture; you can rotate it from a different point, too! */
+ center.x = texture_width / 2;
+ center.y = texture_height / 2;
+ SDL_RenderTextureRotated(renderer, texture, NULL, &dst_rect, rotation, ¢er, SDL_FLIP_NONE);
+
+ 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. */
+}
+