Initial commit

4 files changed, 351 insertions, 0 deletions

diff --git a/contrib/SDL-3.2.8/examples/demo/01-snake/README.txt b/contrib/SDL-3.2.8/examples/demo/01-snake/README.txt
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index 0000000..1cf9784
--- /dev/null
+++ b/contrib/SDL-3.2.8/examples/demo/01-snake/README.txt
@@ -0,0 +1 @@
+A complete game of Snake, written in SDL.
diff --git a/contrib/SDL-3.2.8/examples/demo/01-snake/onmouseover.webp b/contrib/SDL-3.2.8/examples/demo/01-snake/onmouseover.webp
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index 0000000..1757202
--- /dev/null
+++ b/contrib/SDL-3.2.8/examples/demo/01-snake/onmouseover.webp
diff --git a/contrib/SDL-3.2.8/examples/demo/01-snake/snake.c b/contrib/SDL-3.2.8/examples/demo/01-snake/snake.c
new file mode 100644
index 0000000..0aca862
--- /dev/null
+++ b/contrib/SDL-3.2.8/examples/demo/01-snake/snake.c
@@ -0,0 +1,350 @@
+/*
+ * Logic implementation of the Snake game. It is designed to efficiently
+ * represent the state of the game in memory.
+ *
+ * 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>
+
+#define STEP_RATE_IN_MILLISECONDS  125
+#define SNAKE_BLOCK_SIZE_IN_PIXELS 24
+#define SDL_WINDOW_WIDTH           (SNAKE_BLOCK_SIZE_IN_PIXELS * SNAKE_GAME_WIDTH)
+#define SDL_WINDOW_HEIGHT          (SNAKE_BLOCK_SIZE_IN_PIXELS * SNAKE_GAME_HEIGHT)
+
+#define SNAKE_GAME_WIDTH  24U
+#define SNAKE_GAME_HEIGHT 18U
+#define SNAKE_MATRIX_SIZE (SNAKE_GAME_WIDTH * SNAKE_GAME_HEIGHT)
+
+#define THREE_BITS  0x7U /* ~CHAR_MAX >> (CHAR_BIT - SNAKE_CELL_MAX_BITS) */
+#define SHIFT(x, y) (((x) + ((y) * SNAKE_GAME_WIDTH)) * SNAKE_CELL_MAX_BITS)
+
+typedef enum
+{
+    SNAKE_CELL_NOTHING = 0U,
+    SNAKE_CELL_SRIGHT = 1U,
+    SNAKE_CELL_SUP = 2U,
+    SNAKE_CELL_SLEFT = 3U,
+    SNAKE_CELL_SDOWN = 4U,
+    SNAKE_CELL_FOOD = 5U
+} SnakeCell;
+
+#define SNAKE_CELL_MAX_BITS 3U /* floor(log2(SNAKE_CELL_FOOD)) + 1 */
+
+typedef enum
+{
+    SNAKE_DIR_RIGHT,
+    SNAKE_DIR_UP,
+    SNAKE_DIR_LEFT,
+    SNAKE_DIR_DOWN
+} SnakeDirection;
+
+typedef struct
+{
+    unsigned char cells[(SNAKE_MATRIX_SIZE * SNAKE_CELL_MAX_BITS) / 8U];
+    char head_xpos;
+    char head_ypos;
+    char tail_xpos;
+    char tail_ypos;
+    char next_dir;
+    char inhibit_tail_step;
+    unsigned occupied_cells;
+} SnakeContext;
+
+typedef struct
+{
+    SDL_Window *window;
+    SDL_Renderer *renderer;
+    SnakeContext snake_ctx;
+    Uint64 last_step;
+} AppState;
+
+SnakeCell snake_cell_at(const SnakeContext *ctx, char x, char y)
+{
+    const int shift = SHIFT(x, y);
+    unsigned short range;
+    SDL_memcpy(&range, ctx->cells + (shift / 8), sizeof(range));
+    return (SnakeCell)((range >> (shift % 8)) & THREE_BITS);
+}
+
+static void set_rect_xy_(SDL_FRect *r, short x, short y)
+{
+    r->x = (float)(x * SNAKE_BLOCK_SIZE_IN_PIXELS);
+    r->y = (float)(y * SNAKE_BLOCK_SIZE_IN_PIXELS);
+}
+
+static void put_cell_at_(SnakeContext *ctx, char x, char y, SnakeCell ct)
+{
+    const int shift = SHIFT(x, y);
+    const int adjust = shift % 8;
+    unsigned char *const pos = ctx->cells + (shift / 8);
+    unsigned short range;
+    SDL_memcpy(&range, pos, sizeof(range));
+    range &= ~(THREE_BITS << adjust); /* clear bits */
+    range |= (ct & THREE_BITS) << adjust;
+    SDL_memcpy(pos, &range, sizeof(range));
+}
+
+static int are_cells_full_(SnakeContext *ctx)
+{
+    return ctx->occupied_cells == SNAKE_GAME_WIDTH * SNAKE_GAME_HEIGHT;
+}
+
+static void new_food_pos_(SnakeContext *ctx)
+{
+    while (true) {
+        const char x = (char) SDL_rand(SNAKE_GAME_WIDTH);
+        const char y = (char) SDL_rand(SNAKE_GAME_HEIGHT);
+        if (snake_cell_at(ctx, x, y) == SNAKE_CELL_NOTHING) {
+            put_cell_at_(ctx, x, y, SNAKE_CELL_FOOD);
+            break;
+        }
+    }
+}
+
+void snake_initialize(SnakeContext *ctx)
+{
+    int i;
+    SDL_zeroa(ctx->cells);
+    ctx->head_xpos = ctx->tail_xpos = SNAKE_GAME_WIDTH / 2;
+    ctx->head_ypos = ctx->tail_ypos = SNAKE_GAME_HEIGHT / 2;
+    ctx->next_dir = SNAKE_DIR_RIGHT;
+    ctx->inhibit_tail_step = ctx->occupied_cells = 4;
+    --ctx->occupied_cells;
+    put_cell_at_(ctx, ctx->tail_xpos, ctx->tail_ypos, SNAKE_CELL_SRIGHT);
+    for (i = 0; i < 4; i++) {
+        new_food_pos_(ctx);
+        ++ctx->occupied_cells;
+    }
+}
+
+void snake_redir(SnakeContext *ctx, SnakeDirection dir)
+{
+    SnakeCell ct = snake_cell_at(ctx, ctx->head_xpos, ctx->head_ypos);
+    if ((dir == SNAKE_DIR_RIGHT && ct != SNAKE_CELL_SLEFT) ||
+        (dir == SNAKE_DIR_UP && ct != SNAKE_CELL_SDOWN) ||
+        (dir == SNAKE_DIR_LEFT && ct != SNAKE_CELL_SRIGHT) ||
+        (dir == SNAKE_DIR_DOWN && ct != SNAKE_CELL_SUP)) {
+        ctx->next_dir = dir;
+    }
+}
+
+static void wrap_around_(char *val, char max)
+{
+    if (*val < 0) {
+        *val = max - 1;
+    } else if (*val > max - 1) {
+        *val = 0;
+    }
+}
+
+void snake_step(SnakeContext *ctx)
+{
+    const SnakeCell dir_as_cell = (SnakeCell)(ctx->next_dir + 1);
+    SnakeCell ct;
+    char prev_xpos;
+    char prev_ypos;
+    /* Move tail forward */
+    if (--ctx->inhibit_tail_step == 0) {
+        ++ctx->inhibit_tail_step;
+        ct = snake_cell_at(ctx, ctx->tail_xpos, ctx->tail_ypos);
+        put_cell_at_(ctx, ctx->tail_xpos, ctx->tail_ypos, SNAKE_CELL_NOTHING);
+        switch (ct) {
+        case SNAKE_CELL_SRIGHT:
+            ctx->tail_xpos++;
+            break;
+        case SNAKE_CELL_SUP:
+            ctx->tail_ypos--;
+            break;
+        case SNAKE_CELL_SLEFT:
+            ctx->tail_xpos--;
+            break;
+        case SNAKE_CELL_SDOWN:
+            ctx->tail_ypos++;
+            break;
+        default:
+            break;
+        }
+        wrap_around_(&ctx->tail_xpos, SNAKE_GAME_WIDTH);
+        wrap_around_(&ctx->tail_ypos, SNAKE_GAME_HEIGHT);
+    }
+    /* Move head forward */
+    prev_xpos = ctx->head_xpos;
+    prev_ypos = ctx->head_ypos;
+    switch (ctx->next_dir) {
+    case SNAKE_DIR_RIGHT:
+        ++ctx->head_xpos;
+        break;
+    case SNAKE_DIR_UP:
+        --ctx->head_ypos;
+        break;
+    case SNAKE_DIR_LEFT:
+        --ctx->head_xpos;
+        break;
+    case SNAKE_DIR_DOWN:
+        ++ctx->head_ypos;
+        break;
+    }
+    wrap_around_(&ctx->head_xpos, SNAKE_GAME_WIDTH);
+    wrap_around_(&ctx->head_ypos, SNAKE_GAME_HEIGHT);
+    /* Collisions */
+    ct = snake_cell_at(ctx, ctx->head_xpos, ctx->head_ypos);
+    if (ct != SNAKE_CELL_NOTHING && ct != SNAKE_CELL_FOOD) {
+        snake_initialize(ctx);
+        return;
+    }
+    put_cell_at_(ctx, prev_xpos, prev_ypos, dir_as_cell);
+    put_cell_at_(ctx, ctx->head_xpos, ctx->head_ypos, dir_as_cell);
+    if (ct == SNAKE_CELL_FOOD) {
+        if (are_cells_full_(ctx)) {
+            snake_initialize(ctx);
+            return;
+        }
+        new_food_pos_(ctx);
+        ++ctx->inhibit_tail_step;
+        ++ctx->occupied_cells;
+    }
+}
+
+static SDL_AppResult handle_key_event_(SnakeContext *ctx, SDL_Scancode key_code)
+{
+    switch (key_code) {
+    /* Quit. */
+    case SDL_SCANCODE_ESCAPE:
+    case SDL_SCANCODE_Q:
+        return SDL_APP_SUCCESS;
+    /* Restart the game as if the program was launched. */
+    case SDL_SCANCODE_R:
+        snake_initialize(ctx);
+        break;
+    /* Decide new direction of the snake. */
+    case SDL_SCANCODE_RIGHT:
+        snake_redir(ctx, SNAKE_DIR_RIGHT);
+        break;
+    case SDL_SCANCODE_UP:
+        snake_redir(ctx, SNAKE_DIR_UP);
+        break;
+    case SDL_SCANCODE_LEFT:
+        snake_redir(ctx, SNAKE_DIR_LEFT);
+        break;
+    case SDL_SCANCODE_DOWN:
+        snake_redir(ctx, SNAKE_DIR_DOWN);
+        break;
+    default:
+        break;
+    }
+    return SDL_APP_CONTINUE;
+}
+
+SDL_AppResult SDL_AppIterate(void *appstate)
+{
+    AppState *as = (AppState *)appstate;
+    SnakeContext *ctx = &as->snake_ctx;
+    const Uint64 now = SDL_GetTicks();
+    SDL_FRect r;
+    unsigned i;
+    unsigned j;
+    int ct;
+
+    // run game logic if we're at or past the time to run it.
+    // if we're _really_ behind the time to run it, run it
+    // several times.
+    while ((now - as->last_step) >= STEP_RATE_IN_MILLISECONDS) {
+        snake_step(ctx);
+        as->last_step += STEP_RATE_IN_MILLISECONDS;
+    }
+
+    r.w = r.h = SNAKE_BLOCK_SIZE_IN_PIXELS;
+    SDL_SetRenderDrawColor(as->renderer, 0, 0, 0, SDL_ALPHA_OPAQUE);
+    SDL_RenderClear(as->renderer);
+    for (i = 0; i < SNAKE_GAME_WIDTH; i++) {
+        for (j = 0; j < SNAKE_GAME_HEIGHT; j++) {
+            ct = snake_cell_at(ctx, i, j);
+            if (ct == SNAKE_CELL_NOTHING)
+                continue;
+            set_rect_xy_(&r, i, j);
+            if (ct == SNAKE_CELL_FOOD)
+                SDL_SetRenderDrawColor(as->renderer, 80, 80, 255, SDL_ALPHA_OPAQUE);
+            else /* body */
+                SDL_SetRenderDrawColor(as->renderer, 0, 128, 0, SDL_ALPHA_OPAQUE);
+            SDL_RenderFillRect(as->renderer, &r);
+        }
+    }
+    SDL_SetRenderDrawColor(as->renderer, 255, 255, 0, SDL_ALPHA_OPAQUE); /*head*/
+    set_rect_xy_(&r, ctx->head_xpos, ctx->head_ypos);
+    SDL_RenderFillRect(as->renderer, &r);
+    SDL_RenderPresent(as->renderer);
+    return SDL_APP_CONTINUE;
+}
+
+static const struct
+{
+    const char *key;
+    const char *value;
+} extended_metadata[] =
+{
+    { SDL_PROP_APP_METADATA_URL_STRING, "https://examples.libsdl.org/SDL3/demo/01-snake/" },
+    { SDL_PROP_APP_METADATA_CREATOR_STRING, "SDL team" },
+    { SDL_PROP_APP_METADATA_COPYRIGHT_STRING, "Placed in the public domain" },
+    { SDL_PROP_APP_METADATA_TYPE_STRING, "game" }
+};
+
+SDL_AppResult SDL_AppInit(void **appstate, int argc, char *argv[])
+{
+    size_t i;
+
+    if (!SDL_SetAppMetadata("Example Snake game", "1.0", "com.example.Snake")) {
+        return SDL_APP_FAILURE;
+    }
+
+    for (i = 0; i < SDL_arraysize(extended_metadata); i++) {
+        if (!SDL_SetAppMetadataProperty(extended_metadata[i].key, extended_metadata[i].value)) {
+            return SDL_APP_FAILURE;
+        }
+    }
+
+    if (!SDL_Init(SDL_INIT_VIDEO)) {
+        return SDL_APP_FAILURE;
+    }
+
+    AppState *as = (AppState *)SDL_calloc(1, sizeof(AppState));
+    if (!as) {
+        return SDL_APP_FAILURE;
+    }
+
+    *appstate = as;
+
+    if (!SDL_CreateWindowAndRenderer("examples/demo/snake", SDL_WINDOW_WIDTH, SDL_WINDOW_HEIGHT, 0, &as->window, &as->renderer)) {
+        return SDL_APP_FAILURE;
+    }
+
+    snake_initialize(&as->snake_ctx);
+
+    as->last_step = SDL_GetTicks();
+
+    return SDL_APP_CONTINUE;
+}
+
+SDL_AppResult SDL_AppEvent(void *appstate, SDL_Event *event)
+{
+    SnakeContext *ctx = &((AppState *)appstate)->snake_ctx;
+    switch (event->type) {
+    case SDL_EVENT_QUIT:
+        return SDL_APP_SUCCESS;
+    case SDL_EVENT_KEY_DOWN:
+        return handle_key_event_(ctx, event->key.scancode);
+    }
+    return SDL_APP_CONTINUE;
+}
+
+void SDL_AppQuit(void *appstate, SDL_AppResult result)
+{
+    if (appstate != NULL) {
+        AppState *as = (AppState *)appstate;
+        SDL_DestroyRenderer(as->renderer);
+        SDL_DestroyWindow(as->window);
+        SDL_free(as);
+    }
+}
diff --git a/contrib/SDL-3.2.8/examples/demo/01-snake/thumbnail.png b/contrib/SDL-3.2.8/examples/demo/01-snake/thumbnail.png
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index 0000000..f0e27c5
--- /dev/null
+++ b/contrib/SDL-3.2.8/examples/demo/01-snake/thumbnail.png