demo.design 3D programming FAQ. ��. �� .

�� , �� . �� , �� (r,g,b) � �� (light_r,light_g,light_b) ��

result_r = r * light_r / max(light_r);
result_g = g * light_g / max(light_g);
result_b = b * light_b / max(light_b);

�� max(light_r) - �� light_r. �� , �� , � �� . ��, �� light_r �� 0 �� 255, � �� (30, 40,50), �� (k*30,k*40,k*50), �� 0 <= k <= 1, �� max(light_r) = 255, � �� 30. �� , �� .

5.6.1. 256-��

�� 1: �� , �� (��, ��) � ��. �� , � �� (��, ��) �� ; � �� (�� demo.design FAQ) �� true color �� 256x256, � �� (x, y) �� (�� true color!), �� x � �� y, � �� -�� Image Alchemy � 256 ��. �� , � � �� (colorTable) �� :

outputColor = colorTable[intensity][color].

�� 2: �� , �� . �� - �� , � �� - ��, � �� . ��: �� 8 �� 32 �� . �� : 32 �� , ��, ..., ��. �� (�� )

outputColor = (color << 5) + intensity.

5.6.2. 24/32-��

�� . �� , � �� . �� , �� redTable[numShades], greenTable[numShades], blueTable[numShades], � �� :

r = redTable[intensity],
g = greenTable[intensity],
b = blueTable[intensity].

�� - �� , �� .

5.6.3. 15/16-��

�� 1: ��, �� . �� . �� , �� 65536*32 = 2 ��. � �� 32, �� 5 �� (�� 6-�� 16-�� ), � �� , �� 32, ��.

�� 2: �� , �� 24/32-�� . �� -�� , �� . �� , �.�. �� :

000bbbbb          - �����, 8 ���
00000gggggg00000  - �������, 16 ���
rrrrr000          - �������, 8 ���

�� :

outputColor =
   (redTable[(color >> 10) & 0x2F] << 8) +
  greenTable[(color >> 5) & 0x1F] +
   blueTable[color & 0x1F].

�� , ��, �� - � ��. �� :

; ...
mov  bx,color
shr  bx,10
and  bx,02Fh
mov  ah,redTable[bx]
mov  bx,color
and  bx,01Fh
mov  al,blueTable[bx]
mov  bx,color
shr  bx,5      ; ����� �������� ��
and  bx,01Fh   ;   shr  bx,4
shl  bx,1      ;   and  bx,02Eh
or   ax,greenTable[bx]
mov  outputColor,ax
; ...

�� 3: �� 24/32-��, �� 5.6.2, � �� 24/32-�� 15/16. �� PTC � �� . PTC - �� C++, �� http://www.gaffer.org/ptc.