v0.1.0: software map renderer + SDL3 window viewer

2026-09-12 01:02:49 +08:00
parent 3ad380c81e
commit b35372da52
13 changed files with 659 additions and 31 deletions
@@ -0,0 +1,93 @@
+module;
+
+#include <SDL3/SDL.h>
+
+#include <algorithm>
+#include <string>
+
+export module ra3.ui;
+
+export import ra3.core;
+import ra3.render;
+
+/**
+ * A minimal SDL3 window for viewing a rendered scene.
+ *
+ * Controls: drag with the left mouse button to pan, wheel to zoom, Esc/close
+ * to quit. When no display is available `run_viewer` returns false so the
+ * caller can fall back to an offscreen image.
+ */
+export namespace ra3::ui {
+    /** Window parameters. */
+    struct viewer_options {
+        std::string title = "OpenRA3";
+        int width = 1024;
+        int height = 768;
+    };
+
+    /**
+     * Show `scene` in a window until the user quits.
+     *
+     * @return true if the window ran; false if video init or window creation
+     *         failed (typically no display).
+     */
+    [[nodiscard]] inline auto run_viewer(const ra3::render::image &scene, const viewer_options &options) -> bool {
+        if (scene.empty()) return false;
+        if (!SDL_Init(SDL_INIT_VIDEO)) return false;
+
+        SDL_Window *window = SDL_CreateWindow(options.title.c_str(), options.width, options.height, SDL_WINDOW_RESIZABLE);
+        if (window == nullptr) {
+            SDL_Quit();
+            return false;
+        }
+        SDL_Renderer *renderer = SDL_CreateRenderer(window, nullptr);
+        if (renderer == nullptr) {
+            SDL_DestroyWindow(window);
+            SDL_Quit();
+            return false;
+        }
+        SDL_Texture *texture = SDL_CreateTexture(renderer, SDL_PIXELFORMAT_ARGB8888, SDL_TEXTUREACCESS_STREAMING, static_cast<int>(scene.width()),
+                                                 static_cast<int>(scene.height()));
+        if (texture == nullptr) {
+            SDL_DestroyRenderer(renderer);
+            SDL_DestroyWindow(window);
+            SDL_Quit();
+            return false;
+        }
+        SDL_UpdateTexture(texture, nullptr, scene.data(), static_cast<int>(scene.width()) * 4);
+        SDL_SetTextureScaleMode(texture, SDL_SCALEMODE_NEAREST);
+
+        float zoom = 1.0F;
+        float pan_x = 0.0F;
+        float pan_y = 0.0F;
+        bool running = true;
+        SDL_Event event;
+        while (running) {
+            while (SDL_PollEvent(&event)) {
+                if (event.type == SDL_EVENT_QUIT) {
+                    running = false;
+                } else if (event.type == SDL_EVENT_KEY_DOWN && event.key.key == SDLK_ESCAPE) {
+                    running = false;
+                } else if (event.type == SDL_EVENT_MOUSE_WHEEL) {
+                    zoom *= event.wheel.y > 0.0F ? 1.1F : (1.0F / 1.1F);
+                    zoom = std::clamp(zoom, 0.1F, 20.0F);
+                } else if (event.type == SDL_EVENT_MOUSE_MOTION && (event.motion.state & SDL_BUTTON_LMASK) != 0U) {
+                    pan_x += event.motion.xrel;
+                    pan_y += event.motion.yrel;
+                }
+            }
+
+            SDL_SetRenderDrawColor(renderer, 0, 0, 0, 255);
+            SDL_RenderClear(renderer);
+            const SDL_FRect dst{pan_x, pan_y, static_cast<float>(scene.width()) * zoom, static_cast<float>(scene.height()) * zoom};
+            SDL_RenderTexture(renderer, texture, nullptr, &dst);
+            SDL_RenderPresent(renderer);
+        }
+
+        SDL_DestroyTexture(texture);
+        SDL_DestroyRenderer(renderer);
+        SDL_DestroyWindow(window);
+        SDL_Quit();
+        return true;
+    }
+}