1 files changed, 95 insertions, 0 deletions

diff --git a/app/include/gfx/app.h b/app/include/gfx/app.h
new file mode 100644
index 0000000..ffff4bc
--- /dev/null
+++ b/app/include/gfx/app.h
@@ -0,0 +1,95 @@
+#pragma once
+
+#include <stdbool.h>
+
+typedef struct GfxAppState GfxAppState;
+
+/// Application settings.
+typedef struct GfxAppDesc {
+  int          argc;    // Number of application arguments.
+  const char** argv;    // Application arguments.
+  int          width;   // Window width.
+  int          height;  // Window height.
+  int          max_fps; // Desired maximum display framerate. 0 to disable.
+  double       update_delta_time; // Desired delta time between frame updates.
+  const char*  title;             // Window title.
+  GfxAppState* app_state;
+} GfxAppDesc;
+
+typedef bool (*GfxAppInit)(GfxAppState*, int argc, const char** argv);
+typedef void (*GfxAppShutdown)(GfxAppState*);
+typedef void (*GfxAppUpdate)(GfxAppState*, double t, double dt);
+typedef void (*GfxAppRender)(GfxAppState*);
+typedef void (*GfxAppResize)(GfxAppState*, int width, int height);
+
+/// Application callback functions.
+typedef struct GfxAppCallbacks {
+  GfxAppInit     init;
+  GfxAppShutdown shutdown;
+  GfxAppUpdate   update;
+  GfxAppRender   render;
+  GfxAppResize   resize;
+} GfxAppCallbacks;
+
+typedef enum Key {
+  KeyA = 'a',
+  KeyB,
+  KeyC,
+  KeyD,
+  KeyE,
+  KeyF,
+  KeyG,
+  KeyH,
+  KeyI,
+  KeyJ,
+  KeyK,
+  KeyL,
+  KeyM,
+  KeyN,
+  KeyO,
+  KeyP,
+  KeyQ,
+  KeyR,
+  KeyS,
+  KeyT,
+  KeyU,
+  KeyV,
+  KeyW,
+  KeyX,
+  KeyY,
+  KeyZ,
+} Key;
+
+/// Create a window with an OpenGL context and run the main loop.
+bool gfx_app_run(const GfxAppDesc*, const GfxAppCallbacks*);
+
+/// Get the mouse coordinates relative to the app's window.
+void gfx_app_get_mouse_position(double* x, double* y);
+
+/// Return true if the given key is pressed.
+bool gfx_is_key_pressed(Key);
+
+/// Define a main function that initializes and puts the application in a loop.
+/// See also: gfx_app_run().
+#define GFX_APP_MAIN(WIDTH, HEIGHT, MAX_FPS, TITLE)                         \
+  int main(int argc, const char** argv) {                                   \
+    GfxAppState app_state = {0};                                            \
+    gfx_app_run(                                                            \
+        &(GfxAppDesc){                                                      \
+            .argc              = argc,                                      \
+            .argv              = argv,                                      \
+            .width             = WIDTH,                                     \
+            .height            = HEIGHT,                                    \
+            .max_fps           = MAX_FPS,                                   \
+            .update_delta_time = MAX_FPS > 0 ? 1.0 / (double)MAX_FPS : 0.0, \
+            .title             = TITLE,                                     \
+            .app_state         = &app_state,                                \
+        },                                                                  \
+        &(GfxAppCallbacks){                                                 \
+            .init     = (GfxAppInit)app_init,                               \
+            .update   = (GfxAppUpdate)app_update,                           \
+            .render   = (GfxAppRender)app_render,                           \
+            .resize   = (GfxAppResize)app_resize,                           \
+            .shutdown = (GfxAppShutdown)app_end});                          \
+    return 0;                                                               \
+  }