raylib-cs/Examples/models/models_mesh_picking.cs

using Raylib;
using static Raylib.Raylib;
using static Raylib.CameraType;
using static Raylib.CameraMode;
using static Raylib.TexmapIndex;

public partial class models_mesh_picking
{
    /*******************************************************************************************
    *
    *   raylib [models] example - Mesh picking in 3d mode, ground plane, triangle, mesh
    *
    *   This example has been created using raylib 1.7 (www.raylib.com)
    *   raylib is licensed under an unmodified zlib/libpng license (View raylib.h for details)
    *
    *   Copyright (c) 2015 Ramon Santamaria (@raysan5)
    *   Example contributed by Joel Davis (@joeld42)
    *
    ********************************************************************************************/


    public const float FLT_MAX = 3.40282347E+38F;

    public static int Main()
    {
        // Initialization
        //--------------------------------------------------------------------------------------
        int screenWidth = 800;
        int screenHeight = 450;

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

        // Define the camera to look into our 3d world
        Camera3D camera;
        camera.position = new Vector3( 20.0f, 20.0f, 20.0f );  // Camera3D position
        camera.target = new Vector3( 0.0f, 8.0f, 0.0f );      // Camera3D looking at point
        camera.up = new Vector3( 0.0f, 1.6f, 0.0f );          // Camera3D up vector (rotation towards target)
        camera.fovy = 45.0f;                                // Camera3D field-of-view Y
        camera.type = CAMERA_PERSPECTIVE;                   // Camera3D mode type

        Ray ray;        // Picking ray

        Model tower = LoadModel("resources/models/turret.obj");                 // Load OBJ model
        Texture2D texture = LoadTexture("resources/models/turret_diffuse.png"); // Load model texture
        tower.material.maps[(int)MAP_ALBEDO].texture = texture;                     // Set model diffuse texture

        Vector3 towerPos = new Vector3( 0.0f, 0.0f, 0.0f );                    // Set model position
        BoundingBox towerBBox = MeshBoundingBox(tower.mesh);        // Get mesh bounding box
        bool hitMeshBBox = false;
        bool hitTriangle = false;

        // Test triangle
        Vector3 ta = new Vector3( -25.0f, 0.5f, 0.0f );
        Vector3 tb = new Vector3( -4.0f, 2.5f, 1.0f );
        Vector3 tc = new Vector3( -8.0f, 6.5f, 0.0f );

        Vector3 bary = new Vector3( 0.0f, 0.0f, 0.0f );

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

        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(ref camera);          // Update camera

            // Display information about closest hit
            RayHitInfo nearestHit = new RayHitInfo();
            string hitObjectName = "None";
            nearestHit.distance = FLT_MAX;
            nearestHit.hit = false;
            Color cursorColor = WHITE;

            // Get ray and test against ground, triangle, and mesh
            ray = GetMouseRay(GetMousePosition(), camera);

            // Check ray collision aginst ground plane
            RayHitInfo groundHitInfo = GetCollisionRayGround(ray, 0.0f);

            if ((groundHitInfo.hit) && (groundHitInfo.distance < nearestHit.distance))
            {
                nearestHit = groundHitInfo;
                cursorColor = GREEN;
                hitObjectName = "Ground";
            }

            // Check ray collision against test triangle
            RayHitInfo triHitInfo = GetCollisionRayTriangle(ray, ta, tb, tc);

            if ((triHitInfo.hit) && (triHitInfo.distance < nearestHit.distance))
            {
                nearestHit = triHitInfo;
                cursorColor = PURPLE;
                hitObjectName = "Triangle";

                bary = Vector3Barycenter(nearestHit.position, ta, tb, tc);
                hitTriangle = true;
            }
            else hitTriangle = false;

            RayHitInfo meshHitInfo;

            // Check ray collision against bounding box first, before trying the full ray-mesh test
            if (CheckCollisionRayBox(ray, towerBBox))
            {
                hitMeshBBox = true;

                // Check ray collision against model
                // NOTE: It considers model.transform matrix!
                meshHitInfo = GetCollisionRayModel(ray, ref tower);

                if ((meshHitInfo.hit) && (meshHitInfo.distance < nearestHit.distance))
                {
                    nearestHit = meshHitInfo;
                    cursorColor = ORANGE;
                    hitObjectName = "Mesh";
                }

            } hitMeshBBox = false;
            //----------------------------------------------------------------------------------

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

                ClearBackground(RAYWHITE);

                BeginMode3D(camera);

                    // Draw the tower
                    // WARNING: If scale is different than 1.0f,
                    // not considered by GetCollisionRayModel()
                    DrawModel(tower, towerPos, 1.0f, WHITE);

                    // Draw the test triangle
                    DrawLine3D(ta, tb, PURPLE);
                    DrawLine3D(tb, tc, PURPLE);
                    DrawLine3D(tc, ta, PURPLE);

                    // Draw the mesh bbox if we hit it
                    if (hitMeshBBox) DrawBoundingBox(towerBBox, LIME);

                    // If we hit something, draw the cursor at the hit point
                    if (nearestHit.hit)
                    {
                        DrawCube(nearestHit.position, 0.3f, 0.3f, 0.3f, cursorColor);
                        DrawCubeWires(nearestHit.position, 0.3f, 0.3f, 0.3f, RED);

                        Vector3 normalEnd;
                        normalEnd.x = nearestHit.position.x + nearestHit.normal.x;
                        normalEnd.y = nearestHit.position.y + nearestHit.normal.y;
                        normalEnd.z = nearestHit.position.z + nearestHit.normal.z;

                        DrawLine3D(nearestHit.position, normalEnd, RED);
                    }

                    DrawRay(ray, MAROON);

                    DrawGrid(10, 10.0f);

                EndMode3D();

                // Draw some debug GUI text
                DrawText(string.Format("Hit Object: {0}", hitObjectName), 10, 50, 10, BLACK);

                if (nearestHit.hit)
                {
                    int ypos = 70;

                    var x = string.Format("Distance: {0:000.00}", nearestHit.distance);
                    DrawText(string.Format("Distance: {0:000.00}", nearestHit.distance), 10, ypos, 10, BLACK);

                    DrawText(string.Format("Hit Pos: {0:000.00} {1:000.00} {2:000.00}",
                                        nearestHit.position.x,
                                        nearestHit.position.y,
                                        nearestHit.position.z), 10, ypos + 15, 10, BLACK);

                    DrawText(string.Format("Hit Norm: {0:000.00} {1:000.00} {2:000.00}",
                                        nearestHit.normal.x,
                                        nearestHit.normal.y,
                                        nearestHit.normal.z), 10, ypos + 30, 10, BLACK);

                    if (hitTriangle) DrawText(string.Format("Barycenter:{0:000.00} {1:000.00} {2:000.00}",  bary.x, bary.y, bary.z), 10, ypos + 45, 10, BLACK);
                }

                DrawText("Use Mouse to Move Camera", 10, 430, 10, GRAY);

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

                DrawFPS(10, 10);

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

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

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

        return 0;
    }
}