raysan5.raylib/examples/core/core_quat_conversion.c

/*******************************************************************************************
*
*   raylib [core] example - quat conversions
*
*   Generally you should really stick to eulers OR quats...
*   This tests that various conversions are equivalent.
*
*   This example has been created using raylib 3.5 (www.raylib.com)
*   raylib is licensed under an unmodified zlib/libpng license (View raylib.h for details)
*
*   Example contributed by Chris Camacho (@chriscamacho) and reviewed by Ramon Santamaria (@raysan5)
*
*   Copyright (c) 2020-2021 Chris Camacho (@chriscamacho) and Ramon Santamaria (@raysan5)
*
********************************************************************************************/

#include "raylib.h"

#include "raymath.h"

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

    InitWindow(screenWidth, screenHeight, "raylib [core] example - quat conversions");

    Camera3D camera = { 0 };
    camera.position = (Vector3){ 0.0f, 10.0f, 10.0f };  // Camera position
    camera.target = (Vector3){ 0.0f, 0.0f, 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.projection = CAMERA_PERSPECTIVE;             // Camera mode type

    // Load a cylinder model for testing
    Model model = LoadModelFromMesh(GenMeshCylinder(0.2f, 1.0f, 32));

    // Generic quaternion for operations
    Quaternion q1 = { 0 };

    // Transform matrices required to draw 4 cylinders
    Matrix m1 = { 0 };
    Matrix m2 = { 0 };
    Matrix m3 = { 0 };
    Matrix m4 = { 0 };

    // Generic vectors for rotations
    Vector3 v1 = { 0 };
    Vector3 v2 = { 0 };

    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
        //--------------------------------------------------------------------------------------
        if (v2.x < 0) v2.x += PI*2;
        if (v2.y < 0) v2.y += PI*2;
        if (v2.z < 0) v2.z += PI*2;

        if (!IsKeyDown(KEY_SPACE))
        {
            v1.x += 0.01f;
            v1.y += 0.03f;
            v1.z += 0.05f;
        }

        if (v1.x > PI*2) v1.x -= PI*2;
        if (v1.y > PI*2) v1.y -= PI*2;
        if (v1.z > PI*2) v1.z -= PI*2;

        q1 = QuaternionFromEuler(v1.x, v1.y, v1.z);
        m1 = MatrixRotateZYX(v1);
        m2 = QuaternionToMatrix(q1);

        q1 = QuaternionFromMatrix(m1);
        m3 = QuaternionToMatrix(q1);

        v2 = QuaternionToEuler(q1);     // Angles returned in radians

        m4 = MatrixRotateZYX(v2);
        //--------------------------------------------------------------------------------------

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

            ClearBackground(RAYWHITE);

            BeginMode3D(camera);

                model.transform = m1;
                DrawModel(model, (Vector3){ -1, 0, 0 }, 1.0f, RED);

                model.transform = m2;
                DrawModel(model, (Vector3){ 1, 0, 0 }, 1.0f, RED);

                model.transform = m3;
                DrawModel(model, (Vector3){ 0, 0, 0 }, 1.0f, RED);

                model.transform = m4;
                DrawModel(model, (Vector3){ 0, 0, -1 }, 1.0f, RED);

                DrawGrid(10, 1.0f);

            EndMode3D();

            DrawText(TextFormat("%2.3f", v1.x), 20, 20, 20, (v1.x == v2.x)? GREEN: BLACK);
            DrawText(TextFormat("%2.3f", v1.y), 20, 40, 20, (v1.y == v2.y)? GREEN: BLACK);
            DrawText(TextFormat("%2.3f", v1.z), 20, 60, 20, (v1.z == v2.z)? GREEN: BLACK);

            DrawText(TextFormat("%2.3f", v2.x), 200, 20, 20, (v1.x == v2.x)? GREEN: BLACK);
            DrawText(TextFormat("%2.3f", v2.y), 200, 40, 20, (v1.y == v2.y)? GREEN: BLACK);
            DrawText(TextFormat("%2.3f", v2.z), 200, 60, 20, (v1.z == v2.z)? GREEN: BLACK);

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

    // De-Initialization
    //--------------------------------------------------------------------------------------
    UnloadModel(model);   // Unload model data (mesh and materials)

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

    return 0;
}