[wpigui] Add wpigui wrappers for GLFW+imgui

These hide the platform specifics behind a common C++ API. Platforms: - Windows: DirectX 11 (with 10 backwards compatibility) - Linux: OpenGL 3 - Mac: Metal
2026-07-02 02:51:42 +00:00 · 2020-08-25 23:52:09 -07:00
parent 148f43b4a5
commit b80fde4388
17 changed files with 1349 additions and 2 deletions
--- a/wpigui/src/main/native/opengl3/wpigui_opengl3.cpp
+++ b/wpigui/src/main/native/opengl3/wpigui_opengl3.cpp
@@ -0,0 +1,132 @@
+/*----------------------------------------------------------------------------*/
+/* Copyright (c) 2019-2020 FIRST. All Rights Reserved.                        */
+/* Open Source Software - may be modified and shared by FRC teams. The code   */
+/* must be accompanied by the FIRST BSD license file in the root directory of */
+/* the project.                                                               */
+/*----------------------------------------------------------------------------*/
+
+#include <cstdio>
+
+#include <GL/gl3w.h>
+#include <GLFW/glfw3.h>
+#include <imgui.h>
+#include <imgui_impl_glfw.h>
+#include <imgui_impl_opengl3.h>
+#include <stb_image.h>
+
+#include "wpigui.h"
+#include "wpigui_internal.h"
+
+using namespace wpi::gui;
+
+namespace wpi {
+
+void gui::PlatformCreateContext() {}
+
+void gui::PlatformDestroyContext() {}
+
+void gui::PlatformGlfwInitHints() {}
+
+void gui::PlatformGlfwWindowHints() {
+  // Decide GL versions
+#if __APPLE__
+  // GL 3.2 + GLSL 150
+  glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
+  glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 2);
+  glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);  // 3.2+ only
+  glfwWindowHint(GLFW_OPENGL_FORWARD_COMPAT, GL_TRUE);  // Required on Mac
+  glfwWindowHint(GLFW_COCOA_GRAPHICS_SWITCHING, GLFW_TRUE);
+#else
+  // GL 3.0 + GLSL 130
+  glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
+  glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 0);
+  // glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);  // 3.2+
+  // glfwWindowHint(GLFW_OPENGL_FORWARD_COMPAT, GL_TRUE); // 3.0+
+#endif
+
+  // enable 4xMSAA
+  glfwWindowHint(GLFW_SAMPLES, 4);
+}
+
+bool gui::PlatformInitRenderer() {
+  glfwMakeContextCurrent(gContext->window);
+
+  glfwSwapInterval(1);  // Enable vsync
+
+  // Initialize OpenGL loader
+  if (gl3wInit() != 0) {
+    std::fprintf(stderr, "Failed to initialize OpenGL loader!\n");
+    return false;
+  }
+
+  // Turn on multisampling
+  glEnable(GL_MULTISAMPLE);
+
+  // Setup Platform/Renderer bindings
+  ImGui_ImplGlfw_InitForOpenGL(gContext->window, true);
+
+  // Decide GLSL versions
+#if __APPLE__
+  const char* glsl_version = "#version 150";
+#else
+  const char* glsl_version = "#version 130";
+#endif
+  ImGui_ImplOpenGL3_Init(glsl_version);
+
+  return true;
+}
+
+void gui::PlatformRenderFrame() {
+  ImGui_ImplOpenGL3_NewFrame();
+
+  CommonRenderFrame();
+
+  int display_w, display_h;
+  glfwGetFramebufferSize(gContext->window, &display_w, &display_h);
+  glViewport(0, 0, display_w, display_h);
+  glClearColor(gContext->clearColor.x, gContext->clearColor.y,
+               gContext->clearColor.z, gContext->clearColor.w);
+  glClear(GL_COLOR_BUFFER_BIT);
+  ImGui_ImplOpenGL3_RenderDrawData(ImGui::GetDrawData());
+
+  glfwSwapBuffers(gContext->window);
+}
+
+void gui::PlatformShutdown() { ImGui_ImplOpenGL3_Shutdown(); }
+
+bool gui::LoadTextureFromFile(const char* filename, ImTextureID* out_texture,
+                              int* out_width, int* out_height) {
+  // Load from file
+  int width = 0;
+  int height = 0;
+  unsigned char* data = stbi_load(filename, &width, &height, nullptr, 4);
+  if (!data) return false;
+
+  // Create a OpenGL texture identifier
+  GLuint texture;
+  glGenTextures(1, &texture);
+  glBindTexture(GL_TEXTURE_2D, texture);
+
+  // Setup filtering parameters for display
+  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
+  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
+
+  // Upload pixels into texture
+  glPixelStorei(GL_UNPACK_ROW_LENGTH, 0);
+  glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0, GL_RGBA,
+               GL_UNSIGNED_BYTE, data);
+  stbi_image_free(data);
+
+  *out_texture = reinterpret_cast<ImTextureID>(static_cast<uintptr_t>(texture));
+  if (out_width) *out_width = width;
+  if (out_height) *out_height = height;
+
+  return true;
+}
+
+void gui::DeleteTexture(ImTextureID texture) {
+  GLuint glTexture = static_cast<GLuint>(reinterpret_cast<uintptr_t>(texture));
+  if (glTexture != 0) glDeleteTextures(1, &glTexture);
+}
+
+}  // namespace wpi