r4-2.s65

;-------------------------------------------------------------------------
; This code is free software: you can redistribute it and/or modify it
; under the terms of the GNU General Public License as published by
; the Free Software Foundation, either version 3 of the License, or
; (at your option) any later version.

; This code is distributed in the hope that it will be useful, but
; WITHOUT ANY WARRANTY; without even the implied warranty of
; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
; General Public License for more details.

; You should have received a copy of the GNU General Public License
; along with this code. If not, see <https://www.gnu.org/licenses/>.
;-------------------------------------------------------------------------

draw_timer_adjustment=0

                .include "framework.s65"

;-------------------------------------------------------------------------

                .section zp
                .send zp

;-------------------------------------------------------------------------

                .section code

;-------------------------------------------------------------------------

fx_init_1: .proc
                jsr load_mode2_screen
                rts
                .pend

;-------------------------------------------------------------------------

fx_init_2: .proc
                rts
                .pend

;-------------------------------------------------------------------------

fx_update: .proc
                ; .set_crtc 4,38  ;usual Mode 2 value
                rts
                .pend

;-------------------------------------------------------------------------

fx_draw: .proc
                jsr cycles_wait_128
                .set_crtc 4,38
                
                jsr cycles_wait_1024
                jsr cycles_wait_1024

                .set_mode2_palette 0,1
                jsr cycles_wait_128
                .set_mode2_palette 0,0

                ; HD6845 - screen goes initially nuts, as expected,
                ; then settles down (since eventually the fx_draw loop
                ; and the TV end up in sync up enough to give a steady
                ; display)
                ;
                ; VL6845 - screen steady the whole time, as R4 is
                ; never 255 during row 0
                
                .set_crtc 4,$ff
                
                lda #2
-
                bit $fe4d
                beq -
                sta $fe4d
                
                rts
                .pend

;-------------------------------------------------------------------------

                .send code