From fc7e9b526e9e8b2cbf06772d4356700f6560c107 Mon Sep 17 00:00:00 2001
From: Felix Morgner <felix.morgner@gmail.com>
Date: Wed, 18 Feb 2026 10:39:36 +0100
Subject: feat: initialize renderer

---
 src/libs/sdl.S | 10 ++++++++++
 src/main.S     | 50 +++++++++++++++++++++++++++++++++++++++++---------
 2 files changed, 51 insertions(+), 9 deletions(-)

diff --git a/src/libs/sdl.S b/src/libs/sdl.S
index 02302b4..485dfd7 100644
--- a/src/libs/sdl.S
+++ b/src/libs/sdl.S
@@ -1,3 +1,7 @@
+//! @file sdl.S
+//!
+//! Assembler bindings for SDL2
+
 #define SDL_INIT_TIMER           0x00000001u
 #define SDL_INIT_AUDIO           0x00000010u
 #define SDL_INIT_VIDEO           0x00000020u
@@ -5,6 +9,8 @@
 #define SDL_INIT_HAPTIC          0x00001000u
 #define SDL_INIT_GAMECONTROLLER  0x00002000u
 
+#define SDL_RENDERER_ACCELERATED 0x00000002u
+
 #define SDL_WINDOW_SHOWN         0x00000004u
 
 #define SDL_WINDOWPOS_UNDEFINED  0x1FFF0000u
@@ -13,6 +19,10 @@
 .type SDL_Init, @function
 .extern SDL_Init
 
+// SDL_Renderer * SDL_CreateRenderer(SDL_Window * window, int index, Uint32 flags);
+.type SDL_CreateRenderer, @function
+.extern SDL_CreateRenderer
+
 // SDL_Window * SDL_CreateWindow(const char *title, int x, int y, int w, int h, uint32_t flags)
 .type SDL_CreateWindow, @function
 .extern SDL_CreateWindow
diff --git a/src/main.S b/src/main.S
index 11b02e3..20d80e6 100644
--- a/src/main.S
+++ b/src/main.S
@@ -9,16 +9,22 @@
 // callee-saved:    RBX, RSP, RBP, R12-R15
 
 .section .rodata
-  failed_to_create_window:  .string "Window could not be created\nSDL_error: %s\n"
-  failed_to_initialize_sdl: .string "SDL could not be initialized\nSDL_error: %s\n"
-  greeting:                 .string "Hello, SDL!\n"
-  window_title:             .string "snake.s"
+  failed_to_create_renderer:    .string "Renderer could not be created\nSDL_error: %s\n"
+  failed_to_create_window:      .string "Window could not be created\nSDL_error: %s\n"
+  failed_to_initialize_sdl:     .string "SDL could not be initialized\nSDL_error: %s\n"
+
+  succeeded_to_create_renderer: .string "Renderer created successfully!\n"
+  succeeded_to_create_window:   .string "Window created successfully!\n"
+  succeeded_to_initialize_sdl:  .string "SDL2 initialized successfully!\n"
+
+  window_title:                 .string "snake.s"
 
 .section .text
 
   function_begin main
 
     define_local window_handle, 8
+    define_local renderer_handle, 8
     allocate_locals
 
     // initialize SDL
@@ -33,6 +39,9 @@
       mov $1, %rax
       function_exit
   1:
+    lea succeeded_to_initialize_sdl(%rip), %rdi
+    xor %rax, %rax
+    call printf@PLT
 
     // create a window
     lea window_title(%rip), %rdi
@@ -42,7 +51,6 @@
     mov $SCREEN_HEIGHT, %r8
     mov $SDL_WINDOW_SHOWN, %r9
     call SDL_CreateWindow@PLT
-
     store_local %rax, window_handle
 
     // check if window creation was successful
@@ -53,16 +61,40 @@
       mov $1, %rax
       function_exit
   1:
+    lea succeeded_to_create_window(%rip), %rdi
+    xor %rax, %rax
+    call printf@PLT
 
+    // create a renderer
     load_local window_handle, %rdi
-    call SDL_DestroyWindow@PLT
-
-    call SDL_Quit@PLT
+    mov $-1, %rsi
+    mov $SDL_RENDERER_ACCELERATED, %rdx
+    call SDL_CreateRenderer@PLT
+    store_local %rax, renderer_handle
 
-    lea greeting(%rip), %rdi
+    // check if renderer creation was successful
+    test %rax, %rax
+    jne 1f
+      lea failed_to_create_renderer(%rip), %rdi
+      call _print_sdl_error@PLT
+      jmp .Ldestroy_window
+  1:
+    lea succeeded_to_create_renderer(%rip), %rdi
     xor %rax, %rax
     call printf@PLT
 
+  .Ldestroy_renderer:
+    // destroy the renderer
+    load_local renderer_handle, %rdi
+    call SDL_DestroyRenderer
+
+  .Ldestroy_window:
+    // destroy the window
+    load_local window_handle, %rdi
+    call SDL_DestroyWindow@PLT
+
+    call SDL_Quit@PLT
+
     xor %rax, %rax
 
   function_end
-- 
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