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chadowochadowo
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Add basic SDL2 example
1 parent 16be882 commit 579dd14

4 files changed

Lines changed: 220 additions & 2 deletions

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‎CMakeLists.txt‎

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Original file line numberDiff line numberDiff line change
@@ -13,12 +13,16 @@ set(EXAMPLES
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using-cdata
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kwargs
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blocks
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compiling-bytecode)
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compiling-bytecode
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sdl-wrapper)
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set(CMAKE_C_STANDARD 99)
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set(WARNINGS -pedantic -Wall -Wshadow -Wpointer-arith
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-Wno-missing-braces -Wcast-qual -Wstrict-prototypes)
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find_package(SDL2 REQUIRED)
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include_directories(${SDL2_INCLUDE_DIRS})
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foreach(EXAMPLE ${EXAMPLES})
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set(OUTPUT_DIRECTORY "${CMAKE_SOURCE_DIR}/bin/${EXAMPLE}")
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@@ -35,6 +39,11 @@ foreach(EXAMPLE ${EXAMPLES})
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target_compile_options(${EXAMPLE} PRIVATE ${WARNINGS})
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target_link_libraries(${EXAMPLE} PRIVATE -lmruby -lm)
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if("${EXAMPLE}" MATCHES "sdl")
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target_include_directories(${EXAMPLE} PRIVATE ${SDL2_INCLUDE_DIRS})
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target_link_libraries(${EXAMPLE} PRIVATE ${SDL2_LIBRARIES})
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endif()
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endforeach()
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message(STATUS "Binaries will be placed on the bin/ directory relative to the project root")

‎README.md‎

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@@ -26,9 +26,22 @@ Pacman:
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sudo pacman -S mruby
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```
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### Other requirements
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Some examples require SDL2. Install it:
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```console
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$ sudo apt install libsdl2-dev
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```
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or
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```
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$ sudo dnf install SDL2-devel
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```
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### Compiling
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Use the followings commands
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Use the followings commands:
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```console
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cmake -S . -B build
@@ -39,6 +52,8 @@ cmake --build build
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Examples included here:
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### Basic
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| Example | Description |
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|:---------------------------------------------:| --------------------------------------------------------------- |
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| [hello-world](src/hello-world/) | Classic hello world. |
@@ -52,6 +67,12 @@ Examples included here:
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| [blocks](src/blocks/) | Interact with Ruby's block from C. |
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| [compiling-bytecode](src/compiling-bytecode/) | Compile Ruby code into bytecode format and save it on the disk. |
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### SDL2
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| Example | Description |
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|:------------------------------:| --------------------------------------------- |
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| [sdl-wrapper](src/sdl-wrapper) | Basic wrapper around SDL2 to create a window. |
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## Credits
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Credits where due, here are some helpful articles/post/resources that helped

‎src/sdl-wrapper/sdl-wrapper.c‎

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Original file line numberDiff line numberDiff line change
@@ -0,0 +1,170 @@
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#include <stdio.h>
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#include <SDL2/SDL.h>
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#include <mruby.h>
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#include <mruby/class.h>
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#include <mruby/compile.h>
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#include <mruby/data.h>
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#include <mruby/value.h>
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#include <mruby/version.h>
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/* Declarations */
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void freeWindow(mrb_state *mrb, void *ptr);
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typedef struct {
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SDL_Window *win;
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SDL_Renderer *ren;
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SDL_Event e; // Event handler
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} SDLWindowData;
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static const mrb_data_type SDLWindowType = { "Window", freeWindow };
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struct RClass *windowKlass;
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/* Functions */
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static mrb_value mrb_window_new(mrb_state *mrb, mrb_value self) {
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char *title;
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mrb_int w, h;
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mrb_get_args(mrb, "zii", &title, &w, &h);
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SDLWindowData *data = (SDLWindowData *)DATA_PTR(self);
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if (data != NULL) {
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freeWindow(mrb, data);
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}
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// Init stuff ...
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mrb_data_init(self, NULL, &SDLWindowType);
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data = (SDLWindowData *)malloc(sizeof(SDLWindowData));
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data->win = SDL_CreateWindow(title, SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED, w, h, 0);
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data->ren = SDL_CreateRenderer(data->win, -1, SDL_RENDERER_ACCELERATED);
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mrb_data_init(self, data, &SDLWindowType);
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return self;
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}
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/* This functions polls the events from SDL and returns the type of the current event */
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static mrb_value mrb_window_get_events(mrb_state *mrb, mrb_value self) {
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SDLWindowData *idata;
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Data_Get_Struct(mrb, self, &SDLWindowType, idata);
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SDL_PollEvent(&idata->e);
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return mrb_fixnum_value(idata->e.type);
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}
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static mrb_value mrb_window_get_scancode(mrb_state *mrb, mrb_value self) {
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SDLWindowData *idata;
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Data_Get_Struct(mrb, self, &SDLWindowType, idata);
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return mrb_fixnum_value(idata->e.key.keysym.sym);
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}
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static mrb_value mrb_window_render_set_color(mrb_state *mrb, mrb_value self) {
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mrb_int r, g, b, a;
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mrb_get_args(mrb, "iiii", &r, &g, &b, &a);
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SDLWindowData *idata;
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Data_Get_Struct(mrb, self, &SDLWindowType, idata);
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SDL_SetRenderDrawColor(idata->ren, r, g, b, a);
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return mrb_nil_value();
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}
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static mrb_value mrb_window_render_clear(mrb_state *mrb, mrb_value self) {
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SDLWindowData *idata;
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Data_Get_Struct(mrb, self, &SDLWindowType, idata);
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SDL_RenderClear(idata->ren);
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return mrb_nil_value();
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}
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static mrb_value mrb_window_render_present(mrb_state *mrb, mrb_value self) {
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SDLWindowData *idata;
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Data_Get_Struct(mrb, self, &SDLWindowType, idata);
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SDL_RenderPresent(idata->ren);
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return mrb_nil_value();
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}
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static void appendMRubyFunctions(mrb_state *mrb) {
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windowKlass = mrb_define_class(mrb, "SDLWindow", mrb->object_class);
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MRB_SET_INSTANCE_TT(windowKlass, MRB_TT_DATA);
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mrb_define_method(mrb, windowKlass, "initialize", mrb_window_new, MRB_ARGS_REQ(1));
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mrb_define_method(mrb, windowKlass, "poll_event", mrb_window_get_events, MRB_ARGS_NONE());
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mrb_define_method(mrb, windowKlass, "scancode", mrb_window_get_scancode, MRB_ARGS_NONE());
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mrb_define_method(mrb, windowKlass, "render_color", mrb_window_render_set_color, MRB_ARGS_REQ(4));
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mrb_define_method(mrb, windowKlass, "render_clear", mrb_window_render_clear, MRB_ARGS_NONE());
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mrb_define_method(mrb, windowKlass, "render_present", mrb_window_render_present, MRB_ARGS_NONE());
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}
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static void appendSDLConstants(mrb_state *mrb) {
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// Events
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mrb_define_const(mrb, mrb->kernel_module, "SDL_EVENT_QUIT", mrb_fixnum_value(SDL_QUIT));
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mrb_define_const(mrb, mrb->kernel_module, "SDL_EVENT_KEY_DOWN", mrb_fixnum_value(SDL_KEYDOWN));
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// Scancodes
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mrb_define_const(mrb, mrb->kernel_module, "SDLK_ESC", mrb_fixnum_value(SDLK_ESCAPE));
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}
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int main(void) {
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fprintf(stdout, "MRuby version %s", MRUBY_VERSION);
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mrb_state *mrb = mrb_open();
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if (!mrb) {
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fprintf(stderr, "Couldn't initialize MRuby\n");
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return 1;
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}
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if (SDL_Init(SDL_INIT_VIDEO) != 0) {
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fprintf(stderr, "SDL2: Failed to initialize!\n");
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fprintf(stderr, "Error: %s\n", SDL_GetError());
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}
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appendMRubyFunctions(mrb);
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appendSDLConstants(mrb);
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// Open our file
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FILE *rubyScript = fopen("window.rb", "r");
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if (!rubyScript) {
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fprintf(stderr, "Couldn't find a main.rb file in the current directory, quitting...\n");
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mrb_close(mrb);
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return 1;
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}
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// Pass it to MRuby
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mrb_load_file(mrb, rubyScript);
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fclose(rubyScript);
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if (mrb->exc) {
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mrb_print_error(mrb);
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}
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SDL_Quit();
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mrb_close(mrb);
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return 0;
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}
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void freeWindow(mrb_state *mrb, void *ptr) {
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SDLWindowData *data = (SDLWindowData *)ptr;
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if (data != NULL) {
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if (data->ren != NULL) {
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SDL_DestroyRenderer(data->ren);
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}
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if (data->win != NULL) {
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SDL_DestroyWindow(data->win);
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}
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mrb_free(mrb, data);
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}
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}

‎src/sdl-wrapper/window.rb‎

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@@ -0,0 +1,18 @@
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# This file is loaded everytime the executable is ran. Feel free to edit it!
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@window = SDLWindow.new('MRuby SDL Wrapper', 250, 250)
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@running = true
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while @running
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# Event based programming
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case @window.poll_event
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when SDL_EVENT_QUIT
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@running = false
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when SDL_EVENT_KEY_DOWN
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@running = false if @window.scancode == SDLK_ESC
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end
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@window.render_color(255, 100, 100, 255)
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@window.render_clear
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@window.render_present
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end

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