SER332 Lecture 10

Introduction to Graphics and Game Development
Display List and Menus
(201804)

Transcript

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   SER332
   Introduction to Graphics and Game
   Development
   Lecture 10: Display Lists and Menus
   Javier Gonzalez-Sanchez
   javiergs@asu.edu
   PERALTA 230U
   Office Hours: By appointment
   

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2. Javier Gonzalez-Sanchez | SER332 | Spring 2018 | 2
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   Performance
   myDisplay {
   // Square 1 – Vertex 4
   // Square 2 – Vertex 4
   // Square 3 – Vertex 4
   // Square 4 – Vertex 4
   }
   

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   Display Lists
   

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4. Javier Gonzalez-Sanchez | SER332 | Spring 2018 | 4
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   Display Lists
   § What is Display Lists?
   A group of OpenGL functions to be executed on GPU
   § Why using Display Lists is fast?
   glNewList(index, GL_COMPILE);
   glBegin(GL_TRIANGLES);
   …
   glEnd();
   glEndList();
   

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5. Javier Gonzalez-Sanchez | SER332 | Spring 2018 | 5
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   Display List Functions
   § GLuint glGenLists (GLsizei index)
   Generates one or more unused indices. Each display list is identified by an integer
   index.
   § void glNewList(GLuint list, GLenum mode)
   § void glEndList(void)
   Specifies the start and the end of a display list.
   GL_COMPILE: creates the list but the commands are not executed.
   GL_COMPILE_AND_EXECUTE: creates the list and executes the commands
   immediately.
   § void glCallList(GLuint listID)
   Calls a display list and to render a single frame now.
   

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6. Javier Gonzalez-Sanchez | SER332 | Spring 2018 | 6
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   Example
   //https://github.com/javiergs/SER332/blob/master/Lecture10/example_one.c
   #include "glut.h"
   GLuint drawDL;
   void createDisplayList() {
   drawDL = glGenLists(1);
   glNewList(drawDL, GL_COMPILE);
   glBegin(GL_POLYGON);
   glVertex2f(-0.7, 0.7);
   glVertex2f(0.6, 0.7);
   glVertex2f(-0.7, -0.6);
   glEnd();
   glEndList();
   }
   void myInit() {
   displayList();
   ...
   }
   

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   // myDisplay
   void myDisplay() {
   glClear(GL_COLOR_BUFFER_BIT);
   // compare this with example from Lecture 05.
   glCallList(drawDL); // call the list
   glTranslatef(0.05f, 0.05f, 0.0f);
   glRotatef(180, 0.0, 0.0, 1.0);
   glCallList(drawDL); // call the list
   glFlush(); //forces issued commands to execute
   }
   

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8. Javier Gonzalez-Sanchez | SER332 | Spring 2018 | 8
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   Reading
   § To understand the design of display list:
   Red Book: chapter 7, pp.199-201
   § To learn how to use display list:
   Red Book: chapter 7, example 7-1, 7-2
   

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   Pop-Up Menus
   

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10. Javier Gonzalez-Sanchez | SER332 | Spring 2018 | 10
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    Pop-up Menu
    § Create a menu:
    int glutCreateMenu(void (*func)(int value))
    func – the function that will handle the menu events.
    Returned value is the menu identifier.
    § Add entries to the menu:
    void glutAddMenuEntry(char *name, int value)
    Name – the string that show up in the menu
    Value – return to the function when menu entry is selected
    

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11. Javier Gonzalez-Sanchez | SER332 | Spring 2018 | 11
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    Pop-up Menu
    § Attach menu to a mouse button
    void glutAttachMenu(int mouseButton)
    § Attach a submenu
    void glutAddSubMenu(char *entryName, int index)
    entryName – name of submenu entry in the menu.
    index – the index of submenu
    

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12. Javier Gonzalez-Sanchez | SER332 | Spring 2018 | 12
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    Example 2
    // https://github.com/javiergs/SER332/blob/master/Lecture10/ScreenShot%20example_two.png
    void createMenus() {
    //add entries to submenu Colores
    int menuA = glutCreateMenu(menuListener);
    glutAddMenuEntry("Red", 1);
    glutAddMenuEntry("Blue", 2);
    glutAddMenuEntry("Green", 3);
    glutAddMenuEntry("White", 4);
    //add entries to submenu Position
    int menuB = glutCreateMenu(menuListener);
    glutAddMenuEntry("Top", 5);
    glutAddMenuEntry("Center", 6);
    glutAddMenuEntry("Down", 7);
    // create main menu
    int menu = glutCreateMenu(menuListener);
    glutAddSubMenu("Colores", menuA);
    glutAddSubMenu("Position", menuB);
    // attach the menu to the right button
    glutAttachMenu(GLUT_RIGHT_BUTTON);
    }
    void myInit() {
    createMenus();
    

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    Javier Gonzalez-Sanchez | SER332 | Spring 2018 | 13
    // processMenuEvents
    void menuListener(int option) {
    switch (option) {
    case 1:
    r = 1.0f; g=0.0f; b=0.0f; break;
    case 2:
    r = 0.0f; g = 0.0f; b = 1.0f; break;
    case 3:
    r = 0.0f; g = 1.0f; b = 0.0f; break;
    case 4:
    r = 1.0f; g = 1.0f; b = 1.0f; break;
    case 5:
    position_y = 0.3f; break;
    case 6:
    position_y = 0.0f; break;
    case 7:
    position_y = -0.3f; break;
    }
    glutPostRedisplay();
    }
    

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14. Javier Gonzalez-Sanchez | SER332 | Spring 2018 | 14
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    Example 2
    

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    SER332 Introduction to Graphics
    Javier Gonzalez-Sanchez
    javiergs@asu.edu
    Spring 2018
    Disclaimer. These slides can only be used as study material for the class SER332 at ASU. They cannot be distributed or used for another purpose.
    

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