Rename main.c to sdl2-sdlrenderer.c and implement sdl2-opengl3 example

.gitignore

@@ -1,5 +1,6 @@
 .cache
 compile_commands.json
-main
+sdl2-sdlrenderer
+sdl2-opengl3
 extern
 imgui.ini

compile

@@ -3,7 +3,10 @@
 CC=clang
 CFLAGS="-g -Wall $(pkg-config --cflags sdl2) -Wl,-rpath,\$ORIGIN/lib -Ivendor"
 LIBS="$(pkg-config --libs sdl2) -Llib -lcimgui"
-SRC=src/*.c
+SDL2_SDLRENDERER=src/sdl2-sdlrenderer.c
-OUT=main
+SDLRENDERER_OUT=sdl2-sdlrenderer
+SDL2_OPENGL3=src/sdl2-opengl3.c
+OPENGL3_OUT=sdl2-opengl3
 
-(set -x ; $CC $CFLAGS $LIBS $SRC -o $OUT)
+(set -x ; $CC $CFLAGS $LIBS $SDL2_SDLRENDERER -o $SDLRENDERER_OUT)
+(set -x ; $CC $CFLAGS $LIBS -lGL -ldl $SDL2_OPENGL3 -o $OPENGL3_OUT)

src/sdl2-opengl3.c

@@ -0,0 +1,159 @@
+#include "SDL_rect.h"
+#include <SDL2/SDL.h>
+#include <SDL2/SDL_events.h>
+#include <SDL2/SDL_opengl.h>
+#include <SDL2/SDL_render.h>
+#include <SDL2/SDL_video.h>
+#include <stdint.h>
+#include <stdio.h>
+#define CIMGUI_DEFINE_ENUMS_AND_STRUCTS
+#include "cimgui/cimgui.h"
+#define CIMGUI_USE_OPENGL3
+#define CIMGUI_USE_SDL2
+#include "cimgui/cimgui_impl.h"
+#include <GL/gl.h>
+#include <GL/glu.h>
+#include <stdbool.h>
+
+#define WINDOW_WIDTH 1280
+#define WINDOW_HEIGHT 720
+
+int main(void) {
+  SDL_Init(SDL_INIT_EVERYTHING);
+
+  const char *glsl_version = "#version 130";
+  SDL_GL_SetAttribute(SDL_GL_CONTEXT_FLAGS, 0);
+  SDL_GL_SetAttribute(SDL_GL_CONTEXT_PROFILE_MASK, SDL_GL_CONTEXT_PROFILE_CORE);
+  SDL_GL_SetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, 3);
+  SDL_GL_SetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, 0);
+
+  // Create window with graphics context
+  SDL_SetHint(SDL_HINT_RENDER_DRIVER, "opengl");
+  SDL_GL_SetAttribute(SDL_GL_DOUBLEBUFFER, 1);
+  SDL_GL_SetAttribute(SDL_GL_DEPTH_SIZE, 24);
+  SDL_GL_SetAttribute(SDL_GL_STENCIL_SIZE, 8);
+  SDL_DisplayMode current;
+  SDL_GetCurrentDisplayMode(0, &current);
+
+  SDL_WindowFlags window_flags =
+      (SDL_WindowFlags)(SDL_WINDOW_SHOWN | SDL_WINDOW_OPENGL |
+                        SDL_WINDOW_RESIZABLE | SDL_WINDOW_ALLOW_HIGHDPI);
+
+  SDL_Window *window =
+      SDL_CreateWindow("Window", SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED,
+                       WINDOW_WIDTH, WINDOW_HEIGHT, window_flags);
+
+  SDL_GLContext gl_context = SDL_GL_CreateContext(window);
+  SDL_GL_MakeCurrent(window, gl_context);
+  SDL_GL_SetSwapInterval(1); // Enable vsync
+
+  igCreateContext(NULL);
+  ImGuiIO *io = igGetIO();
+  // Enable Keyboard Controls
+  io->ConfigFlags |= ImGuiConfigFlags_NavEnableKeyboard;
+  // Enable Gamepad Controls
+  io->ConfigFlags |= ImGuiConfigFlags_NavEnableGamepad;
+  io->ConfigFlags |= ImGuiConfigFlags_DockingEnable;
+  io->ConfigFlags |= ImGuiConfigFlags_ViewportsEnable;
+
+  igStyleColorsDark(NULL);
+
+  ImGuiStyle *style = igGetStyle();
+  if (io->ConfigFlags & ImGuiConfigFlags_ViewportsEnable) {
+    style->WindowRounding = 0.0f;
+    style->Colors[ImGuiCol_WindowBg].w = 1.0f;
+  }
+
+  if (!ImGui_ImplSDL2_InitForOpenGL(window, gl_context) ||
+      !ImGui_ImplOpenGL3_Init(glsl_version)) {
+    goto IMGUI_FAILED;
+  }
+
+  bool running = true;
+
+  bool show_demo_window = true;
+  ImVec4 clear_color = {0.45f, 0.55f, 0.60f, 1.00f};
+  SDL_Event event = {0};
+
+  while (running) {
+    while (SDL_PollEvent(&event)) {
+      ImGui_ImplSDL2_ProcessEvent(&event);
+      switch (event.type) {
+      case SDL_QUIT:
+        running = false;
+        break;
+      case SDL_WINDOWEVENT:
+        if (event.window.event == SDL_WINDOWEVENT_CLOSE &&
+            event.window.windowID == SDL_GetWindowID(window)) {
+          running = false;
+        }
+        break;
+      }
+    }
+
+    ImGui_ImplOpenGL3_NewFrame();
+    ImGui_ImplSDL2_NewFrame();
+    igNewFrame();
+
+    if (show_demo_window) {
+      igShowDemoWindow(&show_demo_window);
+    }
+
+    {
+      static float f = 0.0f;
+      static int counter = 0;
+
+      igBegin("Hello, world!", NULL, 0);
+
+      igText("This is some useful text.");
+
+      igCheckbox("Demo Window", &show_demo_window);
+
+      igSliderFloat("float", &f, 0.0f, 1.0f, "0.3f", 0);
+      igColorEdit3("clear color", (float *)&clear_color, 0);
+
+      if (igButton("Button", (ImVec2){0, 0})) {
+        counter++;
+      }
+
+      igSameLine(0.0f, -1.0f);
+      igText("counter = %d", counter);
+
+      igText("Application average %.3f ms/frame (%.1f FPS)",
+             1000.0f / io->Framerate, io->Framerate);
+      igEnd();
+    }
+
+    igRender();
+
+    glViewport(0, 0, (int)io->DisplaySize.x, (int)io->DisplaySize.y);
+    glClearColor(clear_color.x * clear_color.w, clear_color.y * clear_color.w,
+                 clear_color.z * clear_color.w, clear_color.w);
+    glClear(GL_COLOR_BUFFER_BIT);
+
+    ImGui_ImplOpenGL3_RenderDrawData(igGetDrawData());
+
+    if (io->ConfigFlags & ImGuiConfigFlags_ViewportsEnable) {
+      SDL_Window *backup_current_window = SDL_GL_GetCurrentWindow();
+      SDL_GLContext backup_current_context = SDL_GL_GetCurrentContext();
+      igUpdatePlatformWindows();
+      igRenderPlatformWindowsDefault(NULL, NULL);
+      SDL_GL_MakeCurrent(backup_current_window, backup_current_context);
+    }
+
+    SDL_GL_SwapWindow(window);
+  }
+
+  ImGui_ImplOpenGL3_Shutdown();
+  ImGui_ImplSDL2_Shutdown();
+  igDestroyContext(NULL);
+
+IMGUI_FAILED:
+  SDL_GL_DeleteContext(gl_context);
+
+  SDL_DestroyWindow(window);
+
+  SDL_Quit();
+
+  return 0;
+}