The User Will Be Able To Interact With The Program Using Mou

He User Will Be Able To Interact With The Program Using Mouse And Keyb

He user will be able to interact with the program using mouse and keyboard. Your canvas (window) and object sizes do not change. Window size is 500x500, and projection type is the orthographic projection. The only difference is the addition of motion and interaction. Here is a list of functionalities you will add to your program: 1) When the user presses the “ESC” key, program stops running and exits. 2) When the user left clicks the mouse on any of four shapes objects (triangle, cross, diamond, or star) on the screen, a black frame will be drawn around the shape, and a text message will appear at the bottom of the screen stating that the object is selected and press “SPACE” to spin. For example, if user clicks on the green star following image will be generated: The thickness of the frame and the font type are up to the programmer. Only one shape can be selected at a time. The mouse selection region does not have to be precise. A circular region at shape center with diameter “n” can be used as the selection region of that shape. 3) After the selection of a shape, the user presses the “SPACE” key. The brown arrow starts spinning clockwise around its center (black point) and randomly stops at a shape (after passing at least 3 and at most 15 shapes). The rotation is expected to be smooth, so the user will see a transition from one shape to another shape. Please set your FPS (frames per second) as 30. There will be 5-degree rotation change between each frame. And each time the user presses the key, arrow will point a random shape. The arrow will never stop between shapes. SPACE key will not work if a shape is not selected. If the arrow stops at the selected shape, a “You win!” message appears at the bottom of the screen. If arrow stops at a different shape, the message will print “You lose!”. For example: 4) Extra Feature (+10 Points): When the user right clicks the mouse on one of the four shape objects (triangle, cross, diamond, and star) a pop-up color menu will appear. The user will see four color options: purple, orange, cyan, and pink. When he/she selects a color, the color of that shape is replaced with the new color. 5) Extra Feature (+10 Points): When the user presses “R/r” key, all four shape objects will be translated (or shifted) counter-clockwise. For instance, one key press will move triangle to the west, star to the south, diamond to the east, and cross to the north (as shown in following figure). Similar to the item 3, this transition will be smooth. The user will see all shapes are moving from their initial positions to their new positions.

Paper For Above instruction

This paper elaborates on the development of an interactive graphics program designed with OpenGL, where user interactions through mouse and keyboard inputs significantly influence the graphical display and animation of geometric shapes. The core features include object selection, animated spinning, color modification, and positional translation, complemented by seamless visual transitions to enhance user experience.

Introduction

Interactive graphics applications serve as fundamental tools in computer graphics education and practical interfaces, allowing users to engage physically with visual elements. The program under discussion provides four geometric shapes—triangle, cross, diamond, and star—displayed within a 500x500 pixel window utilizing orthographic projection. The user can interact via mouse clicks, right-click context menus, and keyboard inputs, with each action triggering specific animations or modifications. This synergy of interaction and visualization exemplifies foundational aspects of user interface programming in graphics systems.

Program Design and Functionality

Basic Window and Object Setup

The window is set to a fixed size of 500x500 pixels, with an orthogonal projection to ensure consistent shape representations regardless of window resizing. Shapes are positioned at predefined coordinates with fixed sizes, ensuring that their visual proportions remain constant. The four shapes are initially rendered in distinct colors, facilitating easy identification.

Object Selection via Mouse

A salient feature is shape selection through mouse clicks. When the user left-clicks on the window, the program detects whether the mouse click occurs within a circular region centered at each shape’s centroid. This region’s diameter 'n' is configurable, but for simplicity, a default value (e.g., 50 pixels) is used. If the click falls within this radius for any shape, that shape is highlighted with a black frame, indicating selection. If multiple shapes are within the selection region, priority or the first detected shape is chosen. Only one shape can be selected at any moment. A message is displayed at the bottom of the screen indicating the selected shape and instructing the user to press 'SPACE' to spin.

Spinning Animation

Once a shape is selected, pressing the 'SPACE' key initiates a spinning animation of an arrow positioned around the shape's center. The arrow rotates clockwise in 5-degree increments at 30 frames per second, with each increment visually smooth to the user. The total rotation corresponds to passing over 3 to 15 shapes randomly, simulating a spinning wheel. Randomness is incorporated by selecting the number of shape intervals the arrow passes through, ensuring unpredictability.

The arrow's rotation is animated such that it does not stop between shapes—only at specific shape positions aligned with division points. When the arrow stops, if it points at the initially selected shape, a "You win!" message appears. Otherwise, a "You lose!" message is displayed. The animation occurs in real-time, providing visual feedback on the spinning process.

Additional Features

Color Change via Right-Click Menu

A context menu appears upon right-clicking any shape, offering four color options: purple, orange, cyan, and pink. When the user selects a color, the shape's color updates instantly, with the transition rendered smoothly during the shape's redraw cycle.

Shape Translation with R/r Keys

Pressing 'R' or 'r' triggers a smooth, animated translation of all four shapes counter-clockwise. The movement shifts each shape to the position of the next shape in the sequence—triangle to the west, star to the south, diamond to the east, and cross to the north—over a transition period. This movement is animated frame-by-frame at 30 FPS, ensuring a seamless visual experience.

Implementation Considerations

Implementing these functionalities requires careful handling of several subsystems:

• Event handling: Detecting keyboard and mouse events, distinguishing between left and right clicks.

• Shape hit detection: Calculating the distance between mouse click points and shape centers, determining whether the click falls within the selection radius.

• Animation loop: Managing the rotation and translation animations with timing control to ensure smoothness. This can be achieved via the rendering loop maintaining a consistent frame rate.

• Context menu management: Displaying, updating, and applying color changes to the shapes dynamically.

• State management: Keeping track of selected shapes, animation states, and user feedback messages.

Conclusion

This interactive graphics program exemplifies the integration of shape rendering, user interaction, and animation in a cohesive manner. By supporting shape selection, randomized spinning, color modification, and positional shifting, it encapsulates essential concepts within computer graphics programming. Attention to detail in smooth animations, efficient event handling, and user feedback ensures an engaging and functional interface suitable for educational and practical applications.

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