feat: add asset path resolution for installed builds

mrpollo · mrpollo · commit c8f2acab23c6 · 2026-03-09T20:41:54.000-07:00
Add asset_path module that resolves asset paths with fallback:
1. User data dir (~/Library/Application Support/ on macOS, XDG_DATA_HOME on Linux)
2. System install dir (compile-time MAVSIM_INSTALL_DATADIR)
3. Relative path (dev/build fallback)

Update all asset load sites in scene, hud, and vehicle to use asset_path().
Add CMake install() rules for binary and assets.
diff --git a/CMakeLists.txt b/CMakeLists.txt
@@ -50,6 +50,7 @@ if(NOT BUILD_TESTING_ONLY)
         src/hud.c
         src/debug_panel.c
         src/ortho_panel.c
+        src/asset_path.c
     )
 
     target_include_directories(mavsim-viewer PRIVATE
@@ -85,4 +86,21 @@ if(NOT BUILD_TESTING_ONLY)
         COMMAND ${CMAKE_COMMAND} -E copy_directory
             ${CMAKE_SOURCE_DIR}/textures $<TARGET_FILE_DIR:mavsim-viewer>/textures
     )
+
+    # Install rules
+    include(GNUInstallDirs)
+
+    target_compile_definitions(mavsim-viewer PRIVATE
+        MAVSIM_INSTALL_DATADIR="${CMAKE_INSTALL_FULL_DATADIR}/mavsim-viewer")
+
+    install(TARGETS mavsim-viewer RUNTIME DESTINATION ${CMAKE_INSTALL_BINDIR})
+    install(DIRECTORY models/ DESTINATION ${CMAKE_INSTALL_DATADIR}/mavsim-viewer/models
+            FILES_MATCHING PATTERN "*.obj" PATTERN "*.mtl")
+    install(DIRECTORY shaders/ DESTINATION ${CMAKE_INSTALL_DATADIR}/mavsim-viewer/shaders
+            FILES_MATCHING PATTERN "*.vs" PATTERN "*.fs")
+    install(DIRECTORY fonts/ DESTINATION ${CMAKE_INSTALL_DATADIR}/mavsim-viewer/fonts
+            FILES_MATCHING PATTERN "*.ttf")
+    install(DIRECTORY textures/ DESTINATION ${CMAKE_INSTALL_DATADIR}/mavsim-viewer/textures
+            FILES_MATCHING PATTERN "*.png")
+    install(FILES fonts/OFL.txt DESTINATION ${CMAKE_INSTALL_DATADIR}/mavsim-viewer/fonts)
 endif()
diff --git a/src/asset_path.c b/src/asset_path.c
@@ -0,0 +1,123 @@
+#include "asset_path.h"
+
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+#include <sys/stat.h>
+
+#ifdef _WIN32
+#include <direct.h>
+#define mkdir_p(path) _mkdir(path)
+#else
+#include <unistd.h>
+#define mkdir_p(path) mkdir(path, 0755)
+#endif
+
+// Cached base directories (set once in asset_path_init)
+static char s_user_data[512];    // user-writable data dir
+static char s_install_data[512]; // system install dir (compile-time)
+
+static int file_exists(const char *path) {
+#ifdef _WIN32
+    struct _stat st;
+    return _stat(path, &st) == 0;
+#else
+    return access(path, R_OK) == 0;
+#endif
+}
+
+// Recursively create directories for a file path
+static void mkdirs_for_file(const char *filepath) {
+    char tmp[512];
+    snprintf(tmp, sizeof(tmp), "%s", filepath);
+
+    // Find last separator
+    char *last_sep = strrchr(tmp, '/');
+#ifdef _WIN32
+    char *last_bsep = strrchr(tmp, '\\');
+    if (last_bsep > last_sep) last_sep = last_bsep;
+#endif
+    if (!last_sep) return;
+    *last_sep = '\0';
+
+    // Create each directory component
+    for (char *p = tmp + 1; *p; p++) {
+        if (*p == '/'
+#ifdef _WIN32
+            || *p == '\\'
+#endif
+        ) {
+            *p = '\0';
+            mkdir_p(tmp);
+            *p = '/';
+        }
+    }
+    mkdir_p(tmp);
+}
+
+void asset_path_init(void) {
+    s_user_data[0] = '\0';
+    s_install_data[0] = '\0';
+
+#ifdef __APPLE__
+    const char *home = getenv("HOME");
+    if (home) {
+        snprintf(s_user_data, sizeof(s_user_data),
+                 "%s/Library/Application Support/mavsim-viewer", home);
+    }
+#elif !defined(_WIN32)
+    // Linux: XDG_DATA_HOME or ~/.local/share
+    const char *xdg = getenv("XDG_DATA_HOME");
+    if (xdg && xdg[0]) {
+        snprintf(s_user_data, sizeof(s_user_data),
+                 "%s/mavsim-viewer", xdg);
+    } else {
+        const char *home = getenv("HOME");
+        if (home) {
+            snprintf(s_user_data, sizeof(s_user_data),
+                     "%s/.local/share/mavsim-viewer", home);
+        }
+    }
+#endif
+
+    // Compile-time install prefix (set by CMake)
+#ifdef MAVSIM_INSTALL_DATADIR
+    snprintf(s_install_data, sizeof(s_install_data),
+             "%s", MAVSIM_INSTALL_DATADIR);
+#endif
+}
+
+void asset_path(const char *subpath, char *out, size_t out_size) {
+    char candidate[512];
+
+    // 1. User data directory
+    if (s_user_data[0]) {
+        snprintf(candidate, sizeof(candidate), "%s/%s", s_user_data, subpath);
+        if (file_exists(candidate)) {
+            snprintf(out, out_size, "%s", candidate);
+            return;
+        }
+    }
+
+    // 2. System install directory
+    if (s_install_data[0]) {
+        snprintf(candidate, sizeof(candidate), "%s/%s", s_install_data, subpath);
+        if (file_exists(candidate)) {
+            snprintf(out, out_size, "%s", candidate);
+            return;
+        }
+    }
+
+    // 3. Relative path (dev/build fallback)
+    snprintf(out, out_size, "%s", subpath);
+}
+
+void asset_write_path(const char *subpath, char *out, size_t out_size) {
+    if (s_user_data[0]) {
+        snprintf(out, out_size, "%s/%s", s_user_data, subpath);
+        mkdirs_for_file(out);
+    } else {
+        // Fallback to relative path
+        snprintf(out, out_size, "%s", subpath);
+    }
+}
diff --git a/src/asset_path.h b/src/asset_path.h
@@ -0,0 +1,23 @@
+#ifndef ASSET_PATH_H
+#define ASSET_PATH_H
+
+#include <stddef.h>
+
+// Initialize asset path resolution. Call once at startup.
+void asset_path_init(void);
+
+// Resolve an asset subpath (e.g. "models/px4_quadrotor.obj") to a full path.
+// Writes into caller-provided buffer. Search order:
+//   macOS:  ~/Library/Application Support/mavsim-viewer/<subpath>
+//   Linux:  $XDG_DATA_HOME/mavsim-viewer/<subpath>
+//   Then:   MAVSIM_INSTALL_DATADIR/<subpath>  (compile-time install prefix)
+//   Then:   ./<subpath>                        (dev/build fallback)
+void asset_path(const char *subpath, char *out, size_t out_size);
+
+// Get a writable path for an asset (for generated files like terrain texture).
+// Always returns the user data directory path, creating directories as needed.
+//   macOS:  ~/Library/Application Support/mavsim-viewer/<subpath>
+//   Linux:  $XDG_DATA_HOME/mavsim-viewer/<subpath>
+void asset_write_path(const char *subpath, char *out, size_t out_size);
+
+#endif
diff --git a/src/hud.c b/src/hud.c
@@ -1,4 +1,5 @@
 #include "hud.h"
+#include "asset_path.h"
 #include "raylib.h"
 #include "raymath.h"
 
@@ -44,8 +45,11 @@ void hud_init(hud_t *h) {
     for (int i = 0; i < HUD_MAX_PINNED; i++)
         h->pinned[i] = -1;
 
-    h->font_value = LoadFontEx("fonts/JetBrainsMono-Medium.ttf", 64, NULL, 0);
-    h->font_label = LoadFontEx("fonts/Inter-Medium.ttf", 48, NULL, 0);
+    char font_path[512];
+    asset_path("fonts/JetBrainsMono-Medium.ttf", font_path, sizeof(font_path));
+    h->font_value = LoadFontEx(font_path, 64, NULL, 0);
+    asset_path("fonts/Inter-Medium.ttf", font_path, sizeof(font_path));
+    h->font_label = LoadFontEx(font_path, 48, NULL, 0);
 
     SetTextureFilter(h->font_value.texture, TEXTURE_FILTER_BILINEAR);
     SetTextureFilter(h->font_label.texture, TEXTURE_FILTER_BILINEAR);
diff --git a/src/main.c b/src/main.c
@@ -15,6 +15,7 @@
 #include "hud.h"
 #include "debug_panel.h"
 #include "ortho_panel.h"
+#include "asset_path.h"
 
 #define MAX_VEHICLES 16
 
@@ -96,6 +97,8 @@ int main(int argc, char *argv[]) {
         }
     }
 
+    asset_path_init();
+
     // Init Raylib
     SetConfigFlags(FLAG_MSAA_4X_HINT | FLAG_WINDOW_RESIZABLE);
     InitWindow(win_w, win_h, "MAVSim Viewer");
diff --git a/src/scene.c b/src/scene.c
@@ -1,4 +1,5 @@
 #include "scene.h"
+#include "asset_path.h"
 #include "raymath.h"
 #include "rlgl.h"
 #include <stdlib.h>
@@ -241,7 +242,10 @@ void scene_init(scene_t *s) {
     };
 
     // Grid shader and plane (100x100 subdivisions for fwidth() precision)
-    s->grid_shader = LoadShader("shaders/grid.vs", "shaders/grid.fs");
+    char vs_path[512], fs_path[512];
+    asset_path("shaders/grid.vs", vs_path, sizeof(vs_path));
+    asset_path("shaders/grid.fs", fs_path, sizeof(fs_path));
+    s->grid_shader = LoadShader(vs_path, fs_path);
     s->loc_colGround  = GetShaderLocation(s->grid_shader, "colGround");
     s->loc_colMinor   = GetShaderLocation(s->grid_shader, "colMinor");
     s->loc_colMajor   = GetShaderLocation(s->grid_shader, "colMajor");
@@ -259,13 +263,17 @@ void scene_init(scene_t *s) {
 
     // Load terrain texture from pre-baked PNG
     double t0 = GetTime();
-    Image terrain_img = LoadImage("textures/terrain.png");
+    char terrain_path[512];
+    asset_path("textures/terrain.png", terrain_path, sizeof(terrain_path));
+    Image terrain_img = LoadImage(terrain_path);
     if (terrain_img.data == NULL) {
-        // Fallback: generate procedurally and export
+        // Fallback: generate procedurally and export to user data dir
         printf("Generating terrain texture...\n");
         s->ground_tex = gen_ground_texture();
         Image export_img = LoadImageFromTexture(s->ground_tex);
-        ExportImage(export_img, "textures/terrain.png");
+        char terrain_write[512];
+        asset_write_path("textures/terrain.png", terrain_write, sizeof(terrain_write));
+        ExportImage(export_img, terrain_write);
         UnloadImage(export_img);
         printf("Terrain texture: %dx%d (%d tiles) exported to textures/terrain.png\n",
                GTEX_ATLAS_W, GTEX_ATLAS_H, GTEX_VARIANTS);
@@ -285,7 +293,9 @@ void scene_init(scene_t *s) {
     s->grid_plane.materials[0].shader = s->grid_shader;
 
     // Vehicle lighting shader — single directional light
-    s->lighting_shader = LoadShader("shaders/lighting.vs", "shaders/lighting.fs");
+    asset_path("shaders/lighting.vs", vs_path, sizeof(vs_path));
+    asset_path("shaders/lighting.fs", fs_path, sizeof(fs_path));
+    s->lighting_shader = LoadShader(vs_path, fs_path);
     s->loc_lightDir  = GetShaderLocation(s->lighting_shader, "lightDir");
     s->loc_ambient   = GetShaderLocation(s->lighting_shader, "ambient");
     s->loc_matNormal = GetShaderLocation(s->lighting_shader, "matNormal");
diff --git a/src/vehicle.c b/src/vehicle.c
@@ -1,4 +1,5 @@
 #include "vehicle.h"
+#include "asset_path.h"
 #include "raymath.h"
 #include "rlgl.h"
 #ifdef _MSC_VER
@@ -74,7 +75,9 @@ void vehicle_load_model(vehicle_t *v, int model_idx) {
     v->pitch_offset_deg = info->pitch_offset_deg;
     v->yaw_offset_deg = info->yaw_offset_deg;
 
-    v->model = LoadModel(info->path);
+    char model_path[512];
+    asset_path(info->path, model_path, sizeof(model_path));
+    v->model = LoadModel(model_path);
     if (v->model.meshCount == 0)
         printf("Warning: failed to load model %s\n", info->path);
 

Original file line number	Diff line number	Diff line change
`@@ -15,6 +15,7 @@`
`15`	`15`	`#include "hud.h"`
`16`	`16`	`#include "debug_panel.h"`
`17`	`17`	`#include "ortho_panel.h"`
	`18`	`+#include "asset_path.h"`
`18`	`19`
`19`	`20`	`#define MAX_VEHICLES 16`
`20`	`21`
`@@ -96,6 +97,8 @@ int main(int argc, char *argv[]) {`
`96`	`97`	`}`
`97`	`98`	`}`
`98`	`99`
	`100`	`+ asset_path_init();`
	`101`	`+`
`99`	`102`	`// Init Raylib`
`100`	`103`	`SetConfigFlags(FLAG_MSAA_4X_HINT \| FLAG_WINDOW_RESIZABLE);`
`101`	`104`	`InitWindow(win_w, win_h, "MAVSim Viewer");`