用鼠標單擊OpenGL拖動3d對象

Question

我試圖左鍵單擊並拖動任何3d對象，如果我放開它，它應該保持在新位置，我將如何實現呢？ 3d對象是從我在頭文件中擁有的繪圖功能加載的。

有人說我應該使用glutMouseFunc或glutMotionFunc。

void MouseClickCallbackFunction(int button, int state, int x, int y)
{

    if (state == GLUT_DOWN) {

    if (button == GLUT_LEFT)
    {
        std::cout << "Left " << x << " " << y <<std::endl;
        leftClick.x = x;
        leftClick.y = y;
    }
    else if (button == GLUT_RIGHT_BUTTON) {

        std::cout << "Right " << x << " " << y << std::endl;
        rightClick.x = x;
        rightClick.y = y;

    }
}
    theGame->mouseClicked(button, state, x, y);
    glutPostRedisplay();

}

/* function MouseMotionCallbackFunction()
 * Description:
 *   - this is called when the mouse is clicked and moves
 */
void MouseMotionCallbackFunction(int x, int y)
{
    theGame->mouseMoved(x, y);
    glutPostRedisplay();
}

int main(int argc, char **argv)
{
    /* initialize the window and OpenGL properly */
    glutInit(&argc, argv);
    glutInitContextVersion(4, 2);
    glutInitWindowSize(WINDOW_WIDTH, WINDOW_HEIGHT);
    glutInitDisplayMode(GLUT_RGBA | GLUT_DOUBLE);
    glutCreateWindow("OpenGL Framework");

    glewExperimental = true;
    if (glewInit() != GLEW_OK)
    {
        std::cout << "GLEW could not be initialized. \n";
        system("pause");
        return 0;
    }

    //glewInit();

    std::cout << "OpenGL version: " << glGetString(GL_VERSION) << std::endl;

    /* set up our function callbacks */
    glutDisplayFunc(DisplayCallbackFunction);
    glutKeyboardFunc(KeyboardCallbackFunction);
    glutKeyboardUpFunc(KeyboardUpCallbackFunction);
    glutMouseFunc(MouseClickCallbackFunction);
    glutMotionFunc(MouseMotionCallbackFunction);
    glutTimerFunc(1, TimerCallbackFunction, 0);

    /* init the game */
    theGame = new Game();
    theGame->initializeGame();

    /* start the game */
    glutMainLoop();
    return 0;
         }

這是帶有對象的繪制功能

void Game::draw()
{
    glClearColor(0, 0, 0, 0);
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

    PassThrough.Bind();
    PassThrough.SendUniformMat4("uModel", MonkeyTransform.data, false);
    PassThrough.SendUniformMat4("uView", CameraTransform.GetInverse().data, false);
    PassThrough.SendUniformMat4("uProj", CameraProjection.data, false);

    PassThrough.SendUniform("uTex", 0);
    PassThrough.SendUniform("LightPosition", CameraTransform.GetInverse() * vec4(4.0f,0.0f,0.0f,1.0f));
    PassThrough.SendUniform("LightAmbient", vec3(0.15f, 0.15f, 0.15f));
    PassThrough.SendUniform("LightDiffuse", vec3(0.7f,0.1f,0.2f));
    PassThrough.SendUniform("LightSpecular", vec3(0.8f,0.1f,0.1f));
    PassThrough.SendUniform("LightSpecularExponent", 50.0f);
    PassThrough.SendUniform("Attenuation_Constant", 1.0f);
    PassThrough.SendUniform("Attenuation_Linear", 0.1f);
    PassThrough.SendUniform("Attenuation_Quadratic", 0.01f);

    glBindVertexArray(Monkey.VAO);
    glDrawArrays(GL_TRIANGLES, 0, Monkey.GetNumVerticies());
    glBindVertexArray(0); 

    PassThrough.unBind();
    glutSwapBuffers();
}

Answer 1

這個概念稱為鼠標拾取。 實現此目的的一種方法是射線投射。 本質上，您要做的就是將鼠標坐標映射到場景中的某個區域。 在您的情況下，您要檢查位置是否在猴子內。 然后，就像處理鼠標的上，下和移動事件一樣簡單。

鼠標向下：檢查是否正在拾取對象。 如果是這樣，那就太好了-也許要突出顯示它或其他東西。 將引用存儲到拾取的對象； 在選擇開始時存儲鼠標的位置（位置）

鼠標移動：鼠標按下了嗎？ 是拾取的對象參考嗎？ 根據鼠標移動事件中pos和坐標之間的增量更新對象位置

鼠標向上：清除拾取的obj ref，位置

此鏈接可能是您感興趣的http://antongerdelan.net/opengl/raycasting.html