| 显示列表可以提高性能，因为他可以存储OPENGL的函数，供以后使用，如果需要多次重绘同一个几何图形，或者如果一次需要多次调用的用于更改状态的函数，把这些函数存储在显示列表中（将显示列表中的矩阵结果集保存，后续使用不需要重复计算以提高性能） 当通过网络在另外一台远程计算机上运算OPENGL程序时，把绘画命令保存在显示列表中具有特别重要意义，由于显示列表是服务器的一部分，这样可以减少网络通信，提高性能 显示列表更像是命令缓存器，而不是动态数据库，也就是说当显示列表创建后，就无法修改。同时显示列表的创建也存在一定的系统开销，因此一个小的显示列表未必会提升性能 |
| 命名和创建，执行显示列表 |
| 1.申请索引值 Gluint listName = glGenLists (Glsizei range); 分配range个连续的，以前未分配的显示列表索引，返回值为连续索引的起始 2.指定显示列表的开始 glNewList (listName, mode); mode:GL_COMPILE GL_COMPILE_AND_EXECUTE 3.OPENGL指令 4.显示列表定义结束 glEndList (); 5.执行显示列表 glCallList (listName); |
| 层次式显示列表 可以创建层次式显示列表，这是一种在glNewList（）与glEndList（）之间调用glCallList（）执行其他显示列表的显示列表 glNewList (listName, mode); glCallList (name1); glCallList (name2); glCallList (name3); glCallList (name4); glEndList (); 显示层次最少的嵌套层次是64，可能更高，通过GL_MAX_LIST_NESTING 属性查询 |
| 管理显示列表索引 Glboolean glIsList(Gluint list) void glDeleteLists(Gluint listm,Glsizei range) |
| 执行多个显示列表 glListBase(base); 指定一个偏移量，它将与glCallLists()函数中的显示列表索引值想加，以获取最终的显示列表索引，显示列表基址对于glCallList(),glNewList()无任何效果 glCallLists (GLsizei n, GLenum type, const GLvoid *lists); 执行n个显示列表 type:GL_BYTE GL_UNSIGNED_BYTE GL_SHORT GL_UNSIGNED_SHORT GL_INT GL_UNSIGNED_INT GL_FLOAT GL_2_BYTES GL_3_BYTES GL_4_BYTES 举例： base = glGenLists (128); glListBase(base); glNewList(base+'A', GL_COMPILE); drawLetter(Adata); glEndList(); glNewList(base+'E', GL_COMPILE); drawLetter(Edata); glEndList(); glNewList(base+'P', GL_COMPILE); drawLetter(Pdata); glEndList(); char *test1 = "A SPARE SERAPE APPEARS AS"; GLsizei len = strlen(s); glCallLists(len, GL_BYTE, (GLbyte *)s); |
| 显示列表管理状态变量 #include "header.h"
GLuint listName;
static void init (void)
{
listName = glGenLists (1);
glNewList (listName, GL_COMPILE);
glColor3f (1.0, 0.0, 0.0);
glBegin (GL_TRIANGLES);
glVertex2f (0.0, 0.0);
glVertex2f (1.0, 0.0);
glVertex2f (0.0, 1.0);
glEnd ();
glTranslatef (1.5, 0.0, 0.0);
glEndList ();
glShadeModel (GL_FLAT);
}
static void drawLine (void)
{
glBegin (GL_LINES);
glVertex2f (0.0, 0.5);
glVertex2f (15.0, 0.5);
glEnd ();
}
void display(void)
{
GLuint i;
glClear (GL_COLOR_BUFFER_BIT);
glColor3f (0.0, 1.0, 0.0);
for (i = 0; i < 10; i++)
glCallList (listName);
drawLine ();
glFlush ();
}
void reshape(int w, int h)
{
glViewport(0, 0, w, h);
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
if (w <= h)
gluOrtho2D (0.0, 2.0, -0.5 * (GLfloat) h/(GLfloat) w,
1.5 * (GLfloat) h/(GLfloat) w);
else
gluOrtho2D (0.0, 2.0 * (GLfloat) w/(GLfloat) h, -0.5, 1.5);
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
}
void keyboard(unsigned char key, int x, int y)
{
switch (key) {
case 27:
exit(0);
break;
}
}
int main(int argc, char** argv)
{
glutInit(&argc, argv);
glutInitDisplayMode (GLUT_SINGLE | GLUT_RGB);
glutInitWindowSize(650, 50);
glutCreateWindow(argv[0]);
init ();
glutReshapeFunc (reshape);
glutDisplayFunc (display);
glutKeyboardFunc (keyboard);
glutMainLoop();
return 0;
}
多个显示列表Demo
#include "header.h"
#include <string.h>
#define PT 1
#define STROKE 2
#define END 3
typedef struct charpoint {
GLfloat x, y;
int type;
} CP;
CP Adata[] = {
{ 0, 0, PT}, {0, 9, PT}, {1, 10, PT}, {4, 10, PT},
{5, 9, PT}, {5, 0, STROKE}, {0, 5, PT}, {5, 5, END}
};
CP Edata[] = {
{5, 0, PT}, {0, 0, PT}, {0, 10, PT}, {5, 10, STROKE},
{0, 5, PT}, {4, 5, END}
};
CP Pdata[] = {
{0, 0, PT}, {0, 10, PT}, {4, 10, PT}, {5, 9, PT}, {5, 6, PT},
{4, 5, PT}, {0, 5, END}
};
CP Rdata[] = {
{0, 0, PT}, {0, 10, PT}, {4, 10, PT}, {5, 9, PT}, {5, 6, PT},
{4, 5, PT}, {0, 5, STROKE}, {3, 5, PT}, {5, 0, END}
};
CP Sdata[] = {
{0, 1, PT}, {1, 0, PT}, {4, 0, PT}, {5, 1, PT}, {5, 4, PT},
{4, 5, PT}, {1, 5, PT}, {0, 6, PT}, {0, 9, PT}, {1, 10, PT},
{4, 10, PT}, {5, 9, END}
};
static void drawLetter(CP *l)
{
glBegin(GL_LINE_STRIP);
while (1) {
switch (l->type) {
case PT:
if(l->y==0)
{
glColor3f(1.0,0.0,0.0);
}
glVertex2i(l->x,l->y);
break;
case STROKE:
glVertex2i(l->x,l->y);
glEnd();
glBegin(GL_LINE_STRIP);
break;
case END:
glVertex2i(l->x,l->y);
glEnd();
glTranslatef(8.0, 0.0, 0.0);
return;
}
l++;
}
}
GLuint base;
static void init (void)
{
GLuint base;
glShadeModel (GL_FLAT);
base = glGenLists (128);
glListBase(base);
glNewList(base+'A', GL_COMPILE); drawLetter(Adata); glEndList();
glNewList(base+'E', GL_COMPILE); drawLetter(Edata); glEndList();
glNewList(base+'P', GL_COMPILE); drawLetter(Pdata); glEndList();
glNewList(base+'R', GL_COMPILE); drawLetter(Rdata); glEndList();
glNewList(base+'S', GL_COMPILE); drawLetter(Sdata); glEndList();
glNewList(base+' ', GL_COMPILE); glTranslatef(8.0, 0.0, 0.0); glEndList();
}
char *test1 = "A SPARE SERAPE APPEARS AS";
char *test2 = "APES PREPARE RARE PEPPERS";
static void printStrokedString(char *s)
{
GLsizei len = strlen(s);
glCallLists(len, GL_BYTE, (GLbyte *)s);
}
void display(void)
{
glClear(GL_COLOR_BUFFER_BIT);
glColor3f(1.0, 1.0, 1.0);
glPushMatrix();
glScalef(2.0, 2.0, 2.0);
glTranslatef(10.0, 30.0, 0.0);
printStrokedString(test1);
glPopMatrix();
glPushMatrix();
glScalef(2.0, 2.0, 2.0);
glTranslatef(10.0, 13.0, 0.0);
printStrokedString(test2);
glPopMatrix();
glFlush();
}
void reshape(int w, int h)
{
glViewport(0, 0, (GLsizei) w, (GLsizei) h);
glMatrixMode (GL_PROJECTION);
glLoadIdentity ();
gluOrtho2D (0.0, (GLdouble) w, 0.0, (GLdouble) h);
}
void keyboard(unsigned char key, int x, int y)
{
switch (key) {
case ' ':
glutPostRedisplay();
break;
case 27:
exit(0);
}
}
int main(int argc, char** argv)
{
glutInit(&argc, argv);
glutInitDisplayMode (GLUT_SINGLE | GLUT_RGB);
glutInitWindowSize (440, 120);
glutCreateWindow ("stroke");
init ();
glutReshapeFunc(reshape);
glutKeyboardFunc(keyboard);
glutDisplayFunc(display);
glutMainLoop();
return 0;
}
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