3 KiB
DAC stands for the QBasic Digital to Analog Converter color attributes used in screens 0, 7 and 9.
** IMPORTANT: QB64 screens do not use the DAC index!**
- DAC colors are preset and cannot be changed in QBasic easily(see example).
- DAC color attribute settings cannot be changed using PALETTE or OUT RGB statements.
- Screen 0 and 9 can use up to 64 DAC color hues. Only attributes 0 to 5 and 7 can have RGB values altered using OUT.
- PALETTE swap statements can assign one attribute's DAC color setting to another attribute color in SCREENs 0 to 9.
- Screen attributes 0 to 5 and 7 can have their RGB settings altered using OUT as shown in Bold below:
***SCREEN 0 or 9 SCREEN 7***
Attribute = DAC setting Attribute = DAC setting
** 0 to 5 = 0 to 5 0 to 5 = 0 to 5**
6 = 20 ** 6 = 6**
7 = 7 7 = 7**
8 = 56 8 = 16
9 = 57 9 = 17
10 = 58 10 = 18
11 = 59 11 = 19
12 = 60 12 = 20
13 = 61 13 = 21
14 = 62 14 = 22
15 = 63 15 = 23
**OUT can change RGB intensities where the DAC value matches the attribute value.**
Changing the DAC attributes to use OUT for custom colors.
SCREEN 9 'use 0, 7 or 9 only"
InitDAC% = INP(&H3DA) ' prepare DAC port for access
FOR attribute% = 6 TO 15 ' attributes 0 to 5 are already non-DAC
OUT &H3C0, attribute% ' send attribute to change
OUT &H3C0, attribute% ' change DAC value to normal number
NEXT attribute%"
OUT &H3C0, 32 ' close port access
Explanation: The procedure is a MUST to import 4 BPP bitmap colors in SCREEN 7 or 9. The InitDAC% value is not used, but that code line opens the DAC color port. Now all color attributes 0 to 15 can be used for custom or imported bitmap RGB color settings.
Disabling blinking colors in fullscreen SCREEN 0 mode enabling high intensity only. (DAC)
D = INP(&H3DA) 'prepares port for access
OUT &H3C0, &H30
OUT &H3C0, 4
Explanation: Make attributes 8-15 available to both foreground AND background colors. In other words it will make fullscreen behave like windowed mode. For the same effect in QB64, use _BLINK OFF.
Enabling: The following code disables above code and returns SCREEN 0 blinking to normal.
D = INP(&H3DA) 'prepares port for access
OUT &H3C0, &H30
OUT &H3C0, 12
NOTE: QB64 allows blinking mode in both fullscreen and windowed modes without using the code above. To reenable blinking in QB64 after using _BLINK OFF, use _BLINK ON.