3D graphics eBook - Course Materials Repository

Vertex Buffer Object 228
//Make the new VBO active
glBindBuffer(GL_ARRAY_BUFFER, triangleVBO);
//Upload vertex data to the video device
glBufferData(GL_ARRAY_BUFFER, sizeof(data), data, GL_STATIC_DRAW);
//Draw Triangle from VBO - do each time window, view point or data
changes
//Establish its 3 coordinates per vertex with zero stride in this
array; necessary here
glVertexPointer(3, GL_FLOAT, 0, NULL);
//Make the new VBO active. Repeat here incase changed since
initialisation
glBindBuffer(GL_ARRAY_BUFFER, triangleVBO);
//Establish array contains vertices (not normals, colours, texture
coords etc)
glEnableClientState(GL_VERTEX_ARRAY);
//Actually draw the triangle, giving the number of vertices provided
glDrawArrays(GL_TRIANGLES, 0, sizeof(data) / sizeof(float) / 3);
//Force display to be drawn now
glFlush();
Example usage in C Using OpenGL 3.x and OpenGL 4.x
Function which can read any text or binary file into char buffer:
/* Function will read a text file into allocated char buffer
*/
char* filetobuf(char *file)
{
are */
FILE *fptr;
long length;
char *buf;
fptr = fopen(file, "r"); /* Open file for reading */
if (!fptr) /* Return NULL on failure */
return NULL;
fseek(fptr, 0, SEEK_END); /* Seek to the end of the file */
length = ftell(fptr); /* Find out how many bytes into the file we
buf = malloc(length+1); /* Allocate a buffer for the entire length
of the file and a null terminator */
*/
fseek(fptr, 0, SEEK_SET); /* Go back to the beginning of the file