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392
Discussion - EVE / Re: BT81x and VERTEX2F
« on: January 31, 2019, 08:37:03 PM »
Nope, bit 3 of VERTEX_FORMAT was correct.
Bit 0..2 are already in use for "frac", although only with a range from 0 to 4.
Bits 3 to 23 are marked as "RESERVED".
While new meaning could be assigned to frac values of 5/6/7, using one of the reserved bits should be more intuitive since the table for the frac values would look very similar to what it is now.
0 1 pixel -8192 to 8191
1 1/2 pixel -4096 to 4095
2 1/4 pixel -2048 to 2047
3 1/8 pixel -1024 to 1023
Bit 0..2 are already in use for "frac", although only with a range from 0 to 4.
Bits 3 to 23 are marked as "RESERVED".
While new meaning could be assigned to frac values of 5/6/7, using one of the reserved bits should be more intuitive since the table for the frac values would look very similar to what it is now.
0 1 pixel -8192 to 8191
1 1/2 pixel -4096 to 4095
2 1/4 pixel -2048 to 2047
3 1/8 pixel -1024 to 1023
393
Discussion - EVE / BT81x and VERTEX2F
« on: January 25, 2019, 11:28:34 AM »
I am a bit disapointed now that the BT81x still has the handbrakes VERTEX2F und VERTEX2II in place with no alternative.
The need to shift the coordindates into the bit-positions only wastes time.
Especially since by default pixel precision for VERTEX2F is 1/16 - and for whatever reason that is.
Looking thru the user-manual I recognize though that it is just not possible to add a VERTEX3F command.
VERTEX2F is 0x01nnnnnn and VERTEX2II is 0x10nnnnnn, neither a 0x00nnnnnn or a 0x11nnnnnn would work because that would make it indistinguishable from the other commands.
This might be the reason why this has not been touched.
However, there would be a way out.
There are 21 reserved bits in VERTEX_FORMAT.
Bit 3 could have been used to change the format of VERTEX2F:
Bit 0...13 = Y
Bit 16...29 = X
With 1 bit less in resolution as a trade-off the frac-value of 0 would be -8192 to 8191, same as 1 and so the maximum pixel precision would be 1/8 pixel.
Can we have this as a patch please for both the FT81x and the BT81x?
The need to shift the coordindates into the bit-positions only wastes time.
Especially since by default pixel precision for VERTEX2F is 1/16 - and for whatever reason that is.
Looking thru the user-manual I recognize though that it is just not possible to add a VERTEX3F command.
VERTEX2F is 0x01nnnnnn and VERTEX2II is 0x10nnnnnn, neither a 0x00nnnnnn or a 0x11nnnnnn would work because that would make it indistinguishable from the other commands.
This might be the reason why this has not been touched.
However, there would be a way out.
There are 21 reserved bits in VERTEX_FORMAT.
Bit 3 could have been used to change the format of VERTEX2F:
Bit 0...13 = Y
Bit 16...29 = X
With 1 bit less in resolution as a trade-off the frac-value of 0 would be -8192 to 8191, same as 1 and so the maximum pixel precision would be 1/8 pixel.
Can we have this as a patch please for both the FT81x and the BT81x?