Add changes to control the bmp image with key events, added chatgpt to links ;)

.fflinks

@@ -0,0 +1,4 @@
+https://lazyfoo.net/tutorials/SDL/index.php
+https://ziglang.org/documentation/0.13.0/std/
+https://ziglang.org/documentation/0.13.0/
+https://chatgpt.com/

src/main.zig

@@ -4,45 +4,25 @@ const c = @cImport({
 
 const std = @import("std");
 const assert = std.debug.assert;
+const SCREEN_WIDTH = 640;
+const SCREEN_HEIGHT = 480;
+const log = c.SDL_Log;
+
+var window: *c.struct_SDL_Window = undefined;
+var screen_surface: *c.struct_SDL_Surface = undefined;
+var zig_image: *c.struct_SDL_Surface = undefined;
+const Offset = struct {
+    x: i32,
+    y: i32,
+};
+var img_pos: Offset = .{ .x = 0, .y = 0 };
 
 pub fn main() !void {
-    if (c.SDL_Init(c.SDL_INIT_VIDEO) != 0) {
+    try init();
-        c.SDL_Log("Unable to initialize SDL: %s", c.SDL_GetError());
+    defer close();
-        return error.SDLInitializationFailed;
-    }
-    defer c.SDL_Quit();
 
-    const screen = c.SDL_CreateWindow("My Game Window", c.SDL_WINDOWPOS_UNDEFINED, c.SDL_WINDOWPOS_UNDEFINED, 400, 140, c.SDL_WINDOW_OPENGL) orelse
+    try loadMedia();
-        {
+    var src_rect: c.struct_SDL_Rect = c.SDL_Rect{ .x = 10, .y = 10, .w = 400, .h = 140 };
-        c.SDL_Log("Unable to create window: %s", c.SDL_GetError());
-        return error.SDLInitializationFailed;
-    };
-    defer c.SDL_DestroyWindow(screen);
-
-    const renderer = c.SDL_CreateRenderer(screen, -1, 0) orelse {
-        c.SDL_Log("Unable to create renderer: %s", c.SDL_GetError());
-        return error.SDLInitializationFailed;
-    };
-    defer c.SDL_DestroyRenderer(renderer);
-
-    const zig_bmp = @embedFile("zig.bmp");
-    const rw = c.SDL_RWFromConstMem(zig_bmp, zig_bmp.len) orelse {
-        c.SDL_Log("Unable to get RWFromConstMem: %s", c.SDL_GetError());
-        return error.SDLInitializationFailed;
-    };
-    defer assert(c.SDL_RWclose(rw) == 0);
-
-    const zig_surface = c.SDL_LoadBMP_RW(rw, 0) orelse {
-        c.SDL_Log("Unable to load bmp: %s", c.SDL_GetError());
-        return error.SDLInitializationFailed;
-    };
-    defer c.SDL_FreeSurface(zig_surface);
-
-    const zig_texture = c.SDL_CreateTextureFromSurface(renderer, zig_surface) orelse {
-        c.SDL_Log("Unable to create texture from surface: %s", c.SDL_GetError());
-        return error.SDLInitializationFailed;
-    };
-    defer c.SDL_DestroyTexture(zig_texture);
 
     var quit = false;
     while (!quit) {
@@ -52,21 +32,67 @@ pub fn main() !void {
                 c.SDL_QUIT => {
                     quit = true;
                 },
+                c.SDL_KEYDOWN => {
+                    switch (event.key.keysym.sym) {
+                        c.SDLK_UP => {
+                            img_pos.y = img_pos.y - 5;
+                        },
+                        c.SDLK_DOWN => {
+                            img_pos.y = img_pos.y + 5;
+                        },
+                        c.SDLK_LEFT => {
+                            img_pos.x = img_pos.x + 5;
+                        },
+                        c.SDLK_RIGHT => {
+                            img_pos.x = img_pos.x - 5;
+                        },
+                        else => {},
+                    }
+                    log("Got key event: %i\n", event.key.keysym.sym);
+                },
                 else => {},
             }
         }
+        _ = c.SDL_FillRect(screen_surface, null, c.SDL_MapRGB(screen_surface.format, 0xff, 0xff, 0xff));
+        var dest_rect = c.SDL_Rect{ .x = src_rect.x + img_pos.x, .y = src_rect.y + img_pos.y, .w = src_rect.w, .h = src_rect.h };
+        _ = c.SDL_BlitSurface(zig_image, &src_rect, screen_surface, &dest_rect);
 
-        _ = c.SDL_RenderClear(renderer);
+        _ = c.SDL_UpdateWindowSurface(window);
-        _ = c.SDL_RenderCopy(renderer, zig_texture, null, null);
-        c.SDL_RenderPresent(renderer);
-
         c.SDL_Delay(17);
     }
+    return;
+}
+
+fn init() !void {
+    // Init SDL with video subsystem flag
+    if (c.SDL_Init(c.SDL_INIT_VIDEO) < 0) {
+        log("Unable to initialize SDL: %s\n", c.SDL_GetError());
+        return error.SDLInitializationFailed;
+    }
+
+    const opt_window = c.SDL_CreateWindow("Game Window", c.SDL_WINDOWPOS_UNDEFINED, c.SDL_WINDOWPOS_UNDEFINED, SCREEN_WIDTH, SCREEN_HEIGHT, c.SDL_WINDOW_SHOWN);
+    if (opt_window == null) {
+        log("Unable to initialize SDL window: %s\n", c.SDL_GetError());
+        return error.SDLInitializationFailed;
+    }
+    window = opt_window.?;
+
+    // get surface and fill with white
+    screen_surface = c.SDL_GetWindowSurface(window);
+}
+
+fn loadMedia() !void {
+    const image: [*c]c.struct_SDL_Surface = c.SDL_LoadBMP("src/zig.bmp");
+    if (image == null) {
+        log("Unable to load media: %s\n", c.SDL_GetError());
+        return error.SDLLoadError;
+    } else {
+        zig_image = image;
+    }
 }
 
-test "simple test" {
+fn close() void {
-    var list = std.ArrayList(i32).init(std.testing.allocator);
+    c.SDL_FreeSurface(zig_image);
-    defer list.deinit(); // try commenting this out and see if zig detects the memory leak!
+    c.SDL_DestroyWindow(window);
-    try list.append(42);
+    c.SDL_Quit();
-    try std.testing.expectEqual(@as(i32, 42), list.pop());
 }