Chủ nhiệm Bộ môn Ngô Hữu Phúc ĐỀ CƯƠng chi tiết bài giảNG

Tiết thứ: 13 - 16 Tuần thứ: 5+6.

- Mục đích, yêu cầu:

• Nắm được cách xây dựng hình ảnh nhân vật với các thao tác di chuyển nhân vật theo các hướng.

• Nắm được hệ thống thước đo và tỉ lệ.

- Hình thức tổ chức dạy học: Lý thuyết, , thực hành, tự học, tự nghiên cứu

- Thời gian: Lý thuyết: 3t; Thực hành: 3t Tự học, tự nghiên cứu: 6t

- Địa điểm: Giảng đường do P2 phân công.

- Nội dung chính:

Lý thuyết:

A sprite is a small image that is moved around on the screen. Many programmers misuse the term to describe any small graphic image in a game. Static, unmoving objects on the screen are not sprites because by definition a sprite is something that moves around and does something on the screen, usually in direct relation to something the player is doing within the game.

• 
  Drawing regular and scaled sprites
  
• 
  Drawing flipped sprites
  
• 
  Drawing rotated and pivoted sprites
  
• 
  Enhancing Tank War
  

1. 
   Drawing Regular Sprites
   

Figure 6.1 A high-color sprite drawn to the screen with a default 8-bit color depth. Sprite image courtesy of Ari Feldman.

Figure 6.2

Figure 6.3

The difference between a sprite drawn with and without transparency. Sprite image courtesy of Ari Feldman.

3. 
   Drawing Scaled Sprites
   

The function is called stretch sprite and it looks like this:

Figure 6.4

A high-resolution sprite image scales quite well. Sprite image courtesy of Ari Feldman.

int main(void)

{

BITMAP *cowboy;

int x, y, n;

float size = 8;

//initialize the program

allegro init();

install keyboard();

set color depth(16);

set gfx mode(GFX AUTODETECT FULLSCREEN, 640, 480, 0, 0);

//print some status information

textprintf ex(screen,font,0,0,WHITE,0,

"Resolution = %ix%i", SCREEN W, SCREEN H);

textprintf ex(screen,font,0,10,WHITE,0,

"Color depth = %i", bitmap color depth(screen));

//load the bitmap

cowboy = load bitmap("spacecowboy1.bmp", NULL);

//draw the sprite

for (n = 0; n < 11; nþ þ) {

y = 30 þ size;

stretch sprite(screen, cowboy, size, y, size, size);

textprintf ex(screen,font,sizeþsizeþ10,y,WHITE,0,"%ix%i",

(int)size,(int)size);

size *= 1.4;

}

//delete the bitmap

destroy bitmap(cowboy);

while(!keypressed());

allegro exit();

return 0;

}

END OF MAIN()

6.4 Drawing Flipped Sprites

Now imagine eliminating the east-, west-, and south-facing

bitmaps from the game by simply drawing the north-facing bitmap in one of the

four directions using a special version of draw sprite for each one. In addition to

the standard draw sprite, you now have the use of three more functions to flip

the sprite three ways: