/*******************************************************************************************
*
*   raylib [models] example - Models loading
*
*   raylib supports multiple models file formats:
*
*     - OBJ > Text file, must include vertex position-texcoords-normals information,
*             if files references some .mtl materials file, it will be loaded (or try to)
*     - GLTF > Modern text/binary file format, includes lot of information and it could
*              also reference external files, raylib will try loading mesh and materials data
*     - IQM > Binary file format including mesh vertex data but also animation data,
*             raylib can load .iqm animations.  
*
*   This example has been created using raylib 2.6 (www.raylib.com)
*   raylib is licensed under an unmodified zlib/libpng license (View raylib.h for details)
*
*   Copyright (c) 2014-2019 Ramon Santamaria (@raysan5)
*
********************************************************************************************/

#include "raylib.h"

int main(void)
{
    // Initialization
    //--------------------------------------------------------------------------------------
    const int screenWidth = 800;
    const int screenHeight = 450;

    InitWindow(screenWidth, screenHeight, "raylib [models] example - models loading");

    // Define the camera to look into our 3d world
    Camera camera = { 0 };
    camera.position = (Vector3){ 50.0f, 50.0f, 50.0f }; // Camera position
    camera.target = (Vector3){ 0.0f, 10.0f, 0.0f };     // Camera looking at point
    camera.up = (Vector3){ 0.0f, 1.0f, 0.0f };          // Camera up vector (rotation towards target)
    camera.fovy = 45.0f;                                // Camera field-of-view Y
    camera.type = CAMERA_PERSPECTIVE;                   // Camera mode type

    Model model = LoadModel("resources/models/castle.obj");                 // Load model
    Texture2D texture = LoadTexture("resources/models/castle_diffuse.png"); // Load model texture
    model.materials[0].maps[MAP_DIFFUSE].texture = texture;                 // Set map diffuse texture

    Vector3 position = { 0.0f, 0.0f, 0.0f };                // Set model position
 
    BoundingBox bounds = MeshBoundingBox(model.meshes[0]);  // Set model bounds

    // NOTE: bounds are calculated from the original size of the model,
    // if model is scaled on drawing, bounds must be also scaled

    SetCameraMode(camera, CAMERA_FREE);     // Set a free camera mode

    bool selected = false;          // Selected object flag

    SetTargetFPS(60);               // Set our game to run at 60 frames-per-second
    //--------------------------------------------------------------------------------------

    // Main game loop
    while (!WindowShouldClose())    // Detect window close button or ESC key
    {
        // Update
        //----------------------------------------------------------------------------------
        UpdateCamera(&camera);
        
        // Load new models/textures on drag&drop
        if (IsFileDropped())
        {
            int count = 0;
            char **droppedFiles = GetDroppedFiles(&count);

            if (count == 1) // Only support one file dropped
            {
                if (IsFileExtension(droppedFiles[0], ".obj") ||
                    IsFileExtension(droppedFiles[0], ".gltf") ||
                    IsFileExtension(droppedFiles[0], ".iqm"))       // Model file formats supported
                {
                    UnloadModel(model);                     // Unload previous model
                    model = LoadModel(droppedFiles[0]);     // Load new model
                    model.materials[0].maps[MAP_DIFFUSE].texture = texture; // Set current map diffuse texture

                    bounds = MeshBoundingBox(model.meshes[0]);
                    
                    // TODO: Move camera position from target enough distance to visualize model properly
                }
                else if (IsFileExtension(droppedFiles[0], ".png"))  // Texture file formats supported
                {
                    // Unload current model texture and load new one
                    UnloadTexture(texture);
                    texture = LoadTexture(droppedFiles[0]);
                    model.materials[0].maps[MAP_DIFFUSE].texture = texture;
                }
            }

            ClearDroppedFiles();    // Clear internal buffers
        }

        // Select model on mouse click
        if (IsMouseButtonPressed(MOUSE_LEFT_BUTTON))
        {
            // Check collision between ray and box
            if (CheckCollisionRayBox(GetMouseRay(GetMousePosition(), camera), bounds)) selected = !selected;
            else selected = false;
        }
        //----------------------------------------------------------------------------------

        // Draw
        //----------------------------------------------------------------------------------
        BeginDrawing();

            ClearBackground(RAYWHITE);

            BeginMode3D(camera);

                DrawModel(model, position, 1.0f, WHITE);        // Draw 3d model with texture

                DrawGrid(20, 10.0f);         // Draw a grid

                if (selected) DrawBoundingBox(bounds, GREEN);   // Draw selection box

            EndMode3D();
            
            DrawText("Drag & drop model to load mesh/texture.", 10, GetScreenHeight() - 20, 10, DARKGRAY);
            if (selected) DrawText("MODEL SELECTED", GetScreenWidth() - 110, 10, 10, GREEN);

            DrawText("(c) Castle 3D model by Alberto Cano", screenWidth - 200, screenHeight - 20, 10, GRAY);

            DrawFPS(10, 10);

        EndDrawing();
        //----------------------------------------------------------------------------------
    }

    // De-Initialization
    //--------------------------------------------------------------------------------------
    UnloadTexture(texture);     // Unload texture
    UnloadModel(model);         // Unload model

    CloseWindow();              // Close window and OpenGL context
    //--------------------------------------------------------------------------------------

    return 0;
}