Module 7

Question 1

Is an OpenGL feature that provides methods for uploading vertex data to the video device for rendering

Answer 1

Vertex Buffer Objects

Question 2

Provides substantial performance as data resides in the video device memory rather than the system memory.

Answer 2

Vertex Buffer Objects

Question 3

What OpenGL constant is used to Bind a regular array data to the VBO
Group of answer choices

GL_VERTEX_ARRAY

GL_NORMAL_ARRAY

GL_ELEMENT_ARRAY_BUFFER

GL_ARRAY_BUFFER

Answer 3

GL_ARRAY_BUFFER

Question 4

Complete the program below by copy and pasting the appropriate statements below to its right place.

glBufferData(GL_ARRAY_BUFFER, sizeof(GLfloat)*9, trianglevertices, GL_DYNAMIC_DRAW);
glClear(GL_COLOR_BUFFER_BIT);
glUnmapBuffer(GL_ARRAY_BUFFER);
glDrawArrays(GL_TRIANGLES,0,6);
glutTimerFunc(1000,modifyTriangle,0);
glVertexPointer(3, GL_FLOAT, 0, 0);
mappedVertices = (GLfloat *) glMapBuffer(GL_ARRAY_BUFFER, GL_READ_WRITE);

Consider the program below wherein the display function is used on the display callback of GLUT. The program moves the triangle

void display(){

    glColor4f(.16f,.72f,.08f,1.0f);

    triangle();

    glFlush();

}

void modifyTriangle(int value){

           triangleUpdate=true;

          

           

          

           mappedVertices[]+=.01f; //0

           mappedVertices[]+=.01f; //3

           mappedVertices[]+=.01f; //6

          

          

           glutPostRedisplay();

}

void triangle(){

    if(!triangleUpdate) {

                           GLfloat trianglevertices[] = {

                    0.0f, .75f, 0.0f,

                    -0.75f, 0.0f, 0.0f,

                    0.75f, 0.0f, 0.0f

            };

                           

            glGenBuffers(1, &VBOid);

            glBindBuffer(GL_ARRAY_BUFFER, VBOid);

            
  

 

            glEnableClientState(GL_VERTEX_ARRAY);

            glVertexPointer(3, GL_FLOAT, 0, 0);

            
   

    }else{

               //When for update just draw the primitive object

           

           glDrawArrays(GL_TRIANGLES,0,6);

    }

}

Question 5

Since we will be using some advance functions of OpenGL we will be needing ________ to simplify access to extended OpenGL extensions.

Answer 5

GLEW

Question 6

Copy ___________ where your project source code resides.

Answer 6

glew.cand glew32.dll (x64)

Question 7

Include __________ in your project directory

Answer 7

glew.c

Question 8

GlGenBuffers parameters

Answer 8

Glsizei n
Gluint* buffers

Question 9

obtains n buffer identifiers from its pool of unused buffers

Answer 9

Glsizei n

Question 10

n is the number of buffer idenifiers desired by the application

Answer 10

Gluint buffers

Question 11

vertex array data

Answer 11

GL_ARRAY_BUFFER

Question 12

vertex array indices

Answer 12

GL_ELEMENT_ARRAY_BUFFER

Question 13

uploads all the array information to the graphics card memory.

Answer 13

glBufferData()

Question 14

The data store contents will be modified once and used at most a few times.

Answer 14

GL_STREAM_DRAW

Question 15

The data store contents will be modified once and used many times.

Answer 15

GL_STATIC_DRAW

Question 16

The data store contents will be modified repeatedly and used many times.

Answer 16

GL_DYNAMIC_DRAW

Question 17

Activate and specify pointer to vertex array

Answer 17

glEnableClientState(GL_VERTEX_ARRAY);

Question 18

Include glew initialization calls before the

Answer 18

main loop

Question 19

Map the buffer object into the client’s memory

Answer 19

glMapBuffer(GLenumtarget, GLenumaccess)

Question 20

If GPU is still working with the buffer object, glMapBuffer() will not return until GPU finishes its job

Answer 20

true

Question 21

After modifying the data of VBO, it must be unmapped the buffer object from the client’s memory

Answer 21

true

Question 22

Using regular arrays is more efficient than VBO as it does not need to travel from physical memory to server memory.

Answer 22

false

Question 23

in creating VBO we first create an array to be transferred to the systems memory.
Group of answer choices

True

False

Answer 23

true

Question 24

What function is used for the initialization of OpenGL extensions.

Answer 24

glewInit()

Question 25

To deallocate the buffer we use glDeleteBuff() function: Group of answer choices True False

Answer 25

False

Question 26

Using VBOs are straightforward as they are included in the GLUT library. Group of answer choices True False

Answer 26

False

Question 27

To switch back to normal operation we bind the buffer with a value of ___________. Group of answer choices 0 2 1 3

Answer 27

0