flan/vendor/raylib/shim.c

/* The C half of the raylib binding: one wrapper per `declare` in raylib.flan.
 *
 * The wrappers exist so that no aggregate is ever passed or returned across
 * the Flan/C boundary. raylib takes Color by value and returns Vector2 by
 * value, and a small aggregate is passed differently on x86-64 (<2 x float>,
 * i32), on arm64, and on wasm32. Here, clang classifies each one correctly for
 * whichever target the build is for; in the Flan backend it would be three
 * conventions to reimplement. Everything below therefore trades in scalars and
 * pointers only — see raylib.flan.
 *
 * raylib's own headers are not needed and not used: these prototypes are the
 * declarations, so the build has no dependency on raylib-devel being
 * installed, only on the shared library being linkable.
 */

#include <stdbool.h>
#include <stddef.h>
#include <limits.h>
#include <string.h>

typedef struct { float x, y; } Vector2;
typedef struct { unsigned char r, g, b, a; } Color;
typedef struct { unsigned int id; int width, height, mipmaps, format; } Texture2D;
typedef struct { float x, y, width, height; } Rectangle;
typedef struct { Vector2 offset, target; float rotation, zoom; } Camera2D;

extern void  InitWindow(int width, int height, const char *title);
extern void  CloseWindow(void);
extern bool  WindowShouldClose(void);
extern void  SetTargetFPS(int fps);
extern void  SetTraceLogLevel(int level);
extern bool  IsKeyPressed(int key);
extern bool  IsKeyDown(int key);
extern bool  IsKeyReleased(int key);
extern bool  IsMouseButtonPressed(int button);
extern bool  IsMouseButtonDown(int button);
extern bool  IsMouseButtonReleased(int button);
extern Vector2 GetMousePosition(void);
extern Color GetColor(unsigned int hex);
extern void  BeginDrawing(void);
extern void  EndDrawing(void);
extern void  DrawFPS(int x, int y);
extern void  ClearBackground(Color color);
extern void  DrawRectangle(int x, int y, int width, int height, Color color);
extern void  SetShapesTexture(Texture2D texture, Rectangle source);
extern Texture2D GetShapesTexture(void);
extern Rectangle GetShapesTextureRectangle(void);
extern Rectangle GetCollisionRec(Rectangle a, Rectangle b);
extern Texture2D LoadTexture(const char *fileName);
extern bool  IsTextureValid(Texture2D texture);
extern void  UnloadTexture(Texture2D texture);
extern void  DrawTexture(Texture2D texture, int posX, int posY, Color tint);
extern void  DrawTextureV(Texture2D texture, Vector2 position, Color tint);
extern void  DrawTextureEx(Texture2D texture, Vector2 position, float rotation,
                           float scale, Color tint);
extern void  DrawTextureRec(Texture2D texture, Rectangle source,
                            Vector2 position, Color tint);
extern void  BeginMode2D(Camera2D camera);
extern void  EndMode2D(void);
extern Vector2 GetScreenToWorld2D(Vector2 position, Camera2D camera);
extern Vector2 GetWorldToScreen2D(Vector2 position, Camera2D camera);
extern bool  CheckCollisionRecs(Rectangle rec1, Rectangle rec2);
extern bool  CheckCollisionCircles(Vector2 c1, float r1, Vector2 c2, float r2);
extern bool  CheckCollisionCircleRec(Vector2 center, float radius, Rectangle rec);
extern bool  CheckCollisionCircleLine(Vector2 center, float radius,
                                      Vector2 p1, Vector2 p2);
extern bool  CheckCollisionPointRec(Vector2 point, Rectangle rec);
extern bool  CheckCollisionPointCircle(Vector2 point, Vector2 center, float radius);
extern bool  CheckCollisionPointTriangle(Vector2 point, Vector2 p1, Vector2 p2,
                                         Vector2 p3);
extern bool  CheckCollisionPointLine(Vector2 point, Vector2 p1, Vector2 p2,
                                     int threshold);
extern bool  CheckCollisionPointPoly(Vector2 point, const Vector2 *points,
                                     int pointCount);
extern bool  CheckCollisionLines(Vector2 a1, Vector2 a2, Vector2 b1, Vector2 b2,
                                 Vector2 *collisionPoint);

/* A Flan string arrives as ptr+len and is not NUL-terminated, so a C API that
 * wants a C string needs a copy. Two callers want one: the window title and a
 * texture's file path. Each passes a buffer big enough for what it is — 256
 * for a title, PATH_MAX for a path — and truncating is better than reading
 * past the end. A truncated path fails to open and LoadTexture returns an id
 * of 0, which is what texture-valid? is for. */
static const char *cstr(const char *p, long long n, char *buf, size_t cap) {
  size_t k = (size_t)n < cap - 1 ? (size_t)n : cap - 1;
  memcpy(buf, p, k);
  buf[k] = '\0';
  return buf;
}

void flan_rl_init_window(int width, int height, const char *title, long long n) {
  char buf[256];
  InitWindow(width, height, cstr(title, n, buf, sizeof buf));
}

void flan_rl_close_window(void)          { CloseWindow(); }
bool flan_rl_window_should_close(void)   { return WindowShouldClose(); }
void flan_rl_set_target_fps(int fps)     { SetTargetFPS(fps); }
void flan_rl_set_trace_log_level(int l)  { SetTraceLogLevel(l); }

bool flan_rl_is_key_pressed(int key)     { return IsKeyPressed(key); }
bool flan_rl_is_key_down(int key)        { return IsKeyDown(key); }
bool flan_rl_is_key_released(int key)    { return IsKeyReleased(key); }

bool flan_rl_is_mouse_button_pressed(int b)  { return IsMouseButtonPressed(b); }
bool flan_rl_is_mouse_button_down(int b)     { return IsMouseButtonDown(b); }
bool flan_rl_is_mouse_button_released(int b) { return IsMouseButtonReleased(b); }

void flan_rl_get_mouse_position(Vector2 *out) { *out = GetMousePosition(); }

void flan_rl_get_color(unsigned int hex, Color *out) { *out = GetColor(hex); }

void flan_rl_begin_drawing(void)         { BeginDrawing(); }
void flan_rl_end_drawing(void)           { EndDrawing(); }
void flan_rl_draw_fps(int x, int y)      { DrawFPS(x, y); }

void flan_rl_clear_background(const Color *color) { ClearBackground(*color); }

void flan_rl_draw_rectangle(int x, int y, int width, int height,
                            const Color *color) {
  DrawRectangle(x, y, width, height, *color);
}

void flan_rl_set_shapes_texture(const Texture2D *texture, const Rectangle *source) {
  SetShapesTexture(*texture, *source);
}

void flan_rl_get_shapes_texture(Texture2D *out) { *out = GetShapesTexture(); }

void flan_rl_get_shapes_texture_rectangle(Rectangle *out) {
  *out = GetShapesTextureRectangle();
}

void flan_rl_get_collision_rec(const Rectangle *a, const Rectangle *b,
                               Rectangle *out) {
  *out = GetCollisionRec(*a, *b);
}

void flan_rl_load_texture(const char *path, long long n, Texture2D *out) {
  char buf[PATH_MAX];
  *out = LoadTexture(cstr(path, n, buf, sizeof buf));
}

bool flan_rl_is_texture_valid(const Texture2D *texture) {
  return IsTextureValid(*texture);
}

void flan_rl_unload_texture(const Texture2D *texture) { UnloadTexture(*texture); }

void flan_rl_draw_texture(const Texture2D *texture, int x, int y,
                          const Color *tint) {
  DrawTexture(*texture, x, y, *tint);
}

void flan_rl_draw_texture_v(const Texture2D *texture, const Vector2 *position,
                            const Color *tint) {
  DrawTextureV(*texture, *position, *tint);
}

void flan_rl_draw_texture_ex(const Texture2D *texture, const Vector2 *position,
                             float rotation, float scale, const Color *tint) {
  DrawTextureEx(*texture, *position, rotation, scale, *tint);
}

void flan_rl_draw_texture_rec(const Texture2D *texture, const Rectangle *source,
                              const Vector2 *position, const Color *tint) {
  DrawTextureRec(*texture, *source, *position, *tint);
}

void flan_rl_begin_mode_2d(const Camera2D *camera) { BeginMode2D(*camera); }
void flan_rl_end_mode_2d(void)                     { EndMode2D(); }

void flan_rl_get_screen_to_world_2d(const Vector2 *position,
                                    const Camera2D *camera, Vector2 *out) {
  *out = GetScreenToWorld2D(*position, *camera);
}

void flan_rl_get_world_to_screen_2d(const Vector2 *position,
                                    const Camera2D *camera, Vector2 *out) {
  *out = GetWorldToScreen2D(*position, *camera);
}

bool flan_rl_check_collision_recs(const Rectangle *a, const Rectangle *b) {
  return CheckCollisionRecs(*a, *b);
}

bool flan_rl_check_collision_circles(const Vector2 *c1, float r1,
                                     const Vector2 *c2, float r2) {
  return CheckCollisionCircles(*c1, r1, *c2, r2);
}

bool flan_rl_check_collision_circle_rec(const Vector2 *center, float radius,
                                        const Rectangle *rec) {
  return CheckCollisionCircleRec(*center, radius, *rec);
}

bool flan_rl_check_collision_circle_line(const Vector2 *center, float radius,
                                         const Vector2 *p1, const Vector2 *p2) {
  return CheckCollisionCircleLine(*center, radius, *p1, *p2);
}

bool flan_rl_check_collision_point_rec(const Vector2 *point, const Rectangle *rec) {
  return CheckCollisionPointRec(*point, *rec);
}

bool flan_rl_check_collision_point_circle(const Vector2 *point,
                                          const Vector2 *center, float radius) {
  return CheckCollisionPointCircle(*point, *center, radius);
}

bool flan_rl_check_collision_point_triangle(const Vector2 *point, const Vector2 *a,
                                            const Vector2 *b, const Vector2 *c) {
  return CheckCollisionPointTriangle(*point, *a, *b, *c);
}

bool flan_rl_check_collision_point_line(const Vector2 *point, const Vector2 *p1,
                                        const Vector2 *p2, int threshold) {
  return CheckCollisionPointLine(*point, *p1, *p2, threshold);
}

/* A Flan slice arrives as ptr+len, the same shape a string does. raylib wants
 * an int count, and a polygon with more than INT_MAX points is not a thing
 * that happens; the clamp is there so the conversion is not silent. */
bool flan_rl_check_collision_point_poly(const Vector2 *point,
                                        const Vector2 *points, long long n) {
  if (n > INT_MAX) n = INT_MAX;
  return CheckCollisionPointPoly(*point, points, (int)n);
}

bool flan_rl_check_collision_lines(const Vector2 *a1, const Vector2 *a2,
                                   const Vector2 *b1, const Vector2 *b2,
                                   Vector2 *out) {
  return CheckCollisionLines(*a1, *a2, *b1, *b2, out);
}