; SPDX-FileCopyrightText: 2024-2026 Zayn Otley ; SPDX-License-Identifier: AGPL-3.0-or-later ; See LICENSES/AGPL-3.0-or-later.txt. ; AROS hardware-presentation rotozoomer: 68020 code using Mode7 and a locked bitmap. ; The bitmap remains locked until the IE COPY blit finishes, so AROS cannot reuse it. ; Compare the presentation phase with rotozoomer_aros_api.asm after reading shared setup. ; ============================================================================ ; AROS ROTOZOOMER TUTORIAL: 68020 assembly and locked bitmap presentation ; ============================================================================ ; This program opens a 640 by 480 CUSTOMSCREEN, renders the affine mapping ; into AllocMem memory, then locks the screen bitmap and submits an IE COPY ; blit to the returned base address. ; ; Shared rotozoomer model: ; U = U0 + x*dU_col + y*dU_row ; V = V0 + x*dV_col + y*dV_row ; `compute_frame` produces the signed 16.16 origin and deltas. `render_mode7` ; submits them to the IE blitter and waits for completion. The presentation ; difference is confined to `blit_to_screen`: it must hold the bitmap lock ; until the COPY blit has finished, then unlock it. ; ; The embedded texture is copied into separately allocated memory before the ; frame loop. The Mode7 destination is a back buffer, not the screen bitmap. ; The VSYNC poll yields after the copy; it is not an atomic display swap. ; ============================================================================ include "ie68.inc" ; --- AmigaOS Constants --- MEMF_ANY equ 0 MEMF_CLEAR equ (1<<16) TAG_DONE equ 0 TAG_USER equ $80000000 ; Intuition screen tags SA_Dummy equ (TAG_USER+32) SA_Width equ (SA_Dummy+3) SA_Height equ (SA_Dummy+4) SA_Depth equ (SA_Dummy+5) SA_Title equ (SA_Dummy+8) SA_Type equ (SA_Dummy+13) SA_DisplayID equ (SA_Dummy+18) SA_ShowTitle equ (SA_Dummy+22) SA_Quiet equ (SA_Dummy+24) CUSTOMSCREEN equ $000F ; Intuition window tags WA_Dummy equ (TAG_USER+99) WA_Width equ (WA_Dummy+3) WA_Height equ (WA_Dummy+4) WA_IDCMP equ (WA_Dummy+7) WA_CustomScreen equ (WA_Dummy+13) WA_Backdrop equ (WA_Dummy+34) WA_Borderless equ (WA_Dummy+37) WA_Activate equ (WA_Dummy+38) IDCMP_RAWKEY equ (1<<10) ; CyberGraphX tags CYBRBIDTG_TB equ (TAG_USER+$50000) CYBRBIDTG_Depth equ (CYBRBIDTG_TB+0) CYBRBIDTG_NominalWidth equ (CYBRBIDTG_TB+1) CYBRBIDTG_NominalHeight equ (CYBRBIDTG_TB+2) ; LockBitMapTagList tags LBMI_BYTESPERROW equ $84001006 LBMI_BASEADDRESS equ $84001007 ; Exec LVOs _LVOOpenLibrary equ -552 ; LVO 92 _LVOCloseLibrary equ -414 ; LVO 69 _LVOGetMsg equ -372 ; LVO 62 _LVOReplyMsg equ -378 ; LVO 63 _LVOAllocMem equ -198 ; LVO 33 _LVOFreeMem equ -210 ; LVO 35 ; Intuition LVOs _LVOOpenScreenTagList equ -612 ; LVO 102 _LVOCloseScreen equ -66 ; LVO 11 _LVOOpenWindowTagList equ -606 ; LVO 101 _LVOCloseWindow equ -72 ; LVO 12 ; CyberGraphX LVOs _LVOBestCModeIDTagList equ -60 ; LVO 10 _LVOLockBitMapTagList equ -168 ; LVO 28 _LVOUnLockBitMap equ -174 ; LVO 29 ; Screen struct offsets sc_RastPort equ 84 ; offset to embedded RastPort rp_BitMap equ 4 ; RastPort->BitMap pointer ; IntuiMessage offsets im_Class equ 20 im_Code equ 24 ; Window struct offsets wd_UserPort equ 86 ; Screen dimensions RENDER_W equ 640 RENDER_H equ 480 LINE_BYTES set 2560 ; 640 * 4 (override ie68.inc default) ; Texture TEX_SIZE equ (256*256*4) ; 262144 bytes TEX_STRIDE equ 1024 ; 256 * 4 ; Back buffer BACKBUF_SIZE equ (640*480*4) ; 1228800 bytes ; Animation increments (8.8 fixed-point) ANGLE_INC equ 313 SCALE_INC equ 104 ; Raw key code for ESC RAWKEY_ESC equ $45 ; ============================================================================ ; ENTRY POINT ; ============================================================================ section text,code start: movem.l d0-d7/a0-a6,-(sp) ; --- Get ExecBase --- movea.l 4.w,a6 move.l a6,_ExecBase ; --- Open intuition.library --- lea intuition_name(pc),a1 moveq #39,d0 jsr _LVOOpenLibrary(a6) move.l d0,_IntuitionBase beq .exit ; --- Open cybergraphics.library --- lea cybergfx_name(pc),a1 moveq #40,d0 movea.l _ExecBase,a6 jsr _LVOOpenLibrary(a6) move.l d0,_CyberGfxBase beq .close_intuition ; --- AllocMem: texture buffer --- move.l #TEX_SIZE,d0 move.l #MEMF_ANY|MEMF_CLEAR,d1 movea.l _ExecBase,a6 jsr _LVOAllocMem(a6) move.l d0,texture_buf beq .close_cgfx ; --- AllocMem: back buffer --- move.l #BACKBUF_SIZE,d0 move.l #MEMF_ANY|MEMF_CLEAR,d1 movea.l _ExecBase,a6 jsr _LVOAllocMem(a6) move.l d0,back_buf beq .free_texture ; --- Load texture into texture_buf --- bsr load_texture ; --- BestCModeIDTagList --- lea bestmode_tags(pc),a0 movea.l _CyberGfxBase,a6 jsr _LVOBestCModeIDTagList(a6) move.l d0,display_id cmpi.l #$FFFFFFFF,d0 beq .free_backbuf ; --- Patch screen tags with DisplayID --- lea scr_displayid_val,a0 move.l d0,(a0) ; --- OpenScreenTagList --- suba.l a0,a0 ; NewScreen = NULL lea screen_tags,a1 movea.l _IntuitionBase,a6 jsr _LVOOpenScreenTagList(a6) move.l d0,screen_ptr beq .free_backbuf ; --- Patch window tags with screen pointer --- lea win_screen_val,a0 move.l screen_ptr,(a0) ; --- OpenWindowTagList --- suba.l a0,a0 ; NewWindow = NULL lea window_tags,a1 movea.l _IntuitionBase,a6 jsr _LVOOpenWindowTagList(a6) move.l d0,window_ptr beq .close_screen ; --- Init animation --- clr.l angle_accum clr.l scale_accum bsr start_music ; ============================================================================ ; MAIN LOOP ; ============================================================================ .main_loop: bsr compute_frame bsr render_mode7 bsr blit_to_screen bsr wait_vsync bsr advance_animation bsr check_idcmp tst.l d0 beq .main_loop ; ============================================================================ ; CLEANUP ; ============================================================================ bsr stop_music .close_window: movea.l window_ptr,a0 movea.l _IntuitionBase,a6 jsr _LVOCloseWindow(a6) .close_screen: movea.l screen_ptr,a0 movea.l _IntuitionBase,a6 jsr _LVOCloseScreen(a6) .free_backbuf: move.l back_buf,d0 beq.s .free_texture movea.l d0,a1 move.l #BACKBUF_SIZE,d0 movea.l _ExecBase,a6 jsr _LVOFreeMem(a6) .free_texture: move.l texture_buf,d0 beq.s .close_cgfx movea.l d0,a1 move.l #TEX_SIZE,d0 movea.l _ExecBase,a6 jsr _LVOFreeMem(a6) .close_cgfx: move.l _CyberGfxBase,d0 beq.s .close_intuition movea.l d0,a1 movea.l _ExecBase,a6 jsr _LVOCloseLibrary(a6) .close_intuition: move.l _IntuitionBase,d0 beq.s .exit movea.l d0,a1 movea.l _ExecBase,a6 jsr _LVOCloseLibrary(a6) .exit: movem.l (sp)+,d0-d7/a0-a6 moveq #0,d0 rts ; ============================================================================ ; LOAD TEXTURE: COPY embedded raw data into the AllocMem texture buffer ; ============================================================================ load_texture: move.l #BLT_OP_COPY,BLT_OP lea texture_data(pc),a0 move.l a0,BLT_SRC move.l texture_buf,BLT_DST move.l #256,BLT_WIDTH move.l #256,BLT_HEIGHT move.l #TEX_STRIDE,BLT_SRC_STRIDE move.l #TEX_STRIDE,BLT_DST_STRIDE move.l #1,BLT_CTRL .wait: move.l BLT_CTRL,d0 andi.l #2,d0 bne.s .wait rts ; ============================================================================ ; MUSIC ; ============================================================================ start_music: lea music_path(pc),a0 move.l a0,MEDIA_NAME_PTR clr.l MEDIA_SUBSONG move.l #MEDIA_OP_PLAY,MEDIA_CTRL rts stop_music: move.l #MEDIA_OP_STOP,MEDIA_CTRL rts ; ============================================================================ ; COMPUTE FRAME: same affine calculation as the non-AROS variant ; ============================================================================ compute_frame: movem.l d0-d7,-(sp) move.l angle_accum,d0 lsr.l #8,d0 andi.l #255,d0 move.l scale_accum,d1 lsr.l #8,d1 andi.l #255,d1 ; cos = sine_table[(angle_idx + 64) & 255] move.l d0,d2 addi.l #64,d2 andi.l #255,d2 add.l d2,d2 lea sine_table(pc),a0 move.w (a0,d2.l),d3 ext.l d3 ; sin = sine_table[angle_idx] move.l d0,d2 add.l d2,d2 move.w (a0,d2.l),d4 ext.l d4 ; recip = recip_table[scale_idx] move.l d1,d2 add.l d2,d2 lea recip_table(pc),a1 move.w (a1,d2.l),d5 andi.l #$FFFF,d5 ; CA = cos * recip, SA = sin * recip move.l d3,d6 muls.w d5,d6 move.l d4,d7 muls.w d5,d7 move.l d6,var_ca move.l d7,var_sa ; u0 = 0x800000 - CA*320 + SA*240 move.l d6,d0 move.l d0,d1 lsl.l #8,d0 lsl.l #6,d1 add.l d1,d0 ; CA * 320 move.l d7,d1 move.l d1,d2 lsl.l #8,d1 lsl.l #4,d2 sub.l d2,d1 ; SA * 240 move.l #$800000,d3 sub.l d0,d3 add.l d1,d3 move.l d3,var_u0 ; v0 = 0x800000 - SA*320 - CA*240 move.l d7,d0 move.l d0,d1 lsl.l #8,d0 lsl.l #6,d1 add.l d1,d0 ; SA * 320 move.l d6,d1 move.l d1,d2 lsl.l #8,d1 lsl.l #4,d2 sub.l d2,d1 ; CA * 240 move.l #$800000,d3 sub.l d0,d3 sub.l d1,d3 move.l d3,var_v0 movem.l (sp)+,d0-d7 rts ; ============================================================================ ; RENDER MODE7: texture buffer to back buffer through Mode7 ; ============================================================================ render_mode7: move.l #BLT_OP_MODE7,BLT_OP move.l texture_buf,BLT_SRC move.l back_buf,BLT_DST move.l #RENDER_W,BLT_WIDTH move.l #RENDER_H,BLT_HEIGHT move.l #TEX_STRIDE,BLT_SRC_STRIDE move.l #LINE_BYTES,BLT_DST_STRIDE move.l #255,BLT_MODE7_TEX_W move.l #255,BLT_MODE7_TEX_H move.l var_u0,d0 move.l d0,BLT_MODE7_U0 move.l var_v0,d0 move.l d0,BLT_MODE7_V0 move.l var_ca,d0 move.l d0,BLT_MODE7_DU_COL move.l var_sa,d0 move.l d0,BLT_MODE7_DV_COL neg.l d0 move.l d0,BLT_MODE7_DU_ROW move.l var_ca,d0 move.l d0,BLT_MODE7_DV_ROW move.l #1,BLT_CTRL .wait: move.l BLT_CTRL,d0 andi.l #2,d0 bne.s .wait rts ; ============================================================================ ; BLIT TO SCREEN: lock bitmap, COPY back buffer, then unlock ; ============================================================================ blit_to_screen: ; Lock the screen bitmap movea.l screen_ptr,a0 lea sc_RastPort(a0),a0 movea.l rp_BitMap(a0),a0 ; a0 = BitMap lea lbmi_tags,a1 movea.l _CyberGfxBase,a6 jsr _LVOLockBitMapTagList(a6) tst.l d0 beq.s .done move.l d0,lock_handle ; BLIT COPY from back buffer to screen VRAM move.l #BLT_OP_COPY,BLT_OP move.l back_buf,BLT_SRC move.l screen_vram,BLT_DST move.l #RENDER_W,BLT_WIDTH move.l #RENDER_H,BLT_HEIGHT move.l #LINE_BYTES,BLT_SRC_STRIDE move.l screen_stride,BLT_DST_STRIDE move.l #1,BLT_CTRL .waitblt: move.l BLT_CTRL,d0 andi.l #2,d0 bne.s .waitblt ; Unlock movea.l lock_handle,a0 movea.l _CyberGfxBase,a6 jsr _LVOUnLockBitMap(a6) .done: rts ; ============================================================================ ; WAIT VSYNC: two-phase edge detection ; ============================================================================ wait_vsync: .wait_end: move.l VIDEO_STATUS,d0 andi.l #STATUS_VBLANK,d0 bne.s .wait_end .wait_start: move.l VIDEO_STATUS,d0 andi.l #STATUS_VBLANK,d0 beq.s .wait_start rts ; ============================================================================ ; ADVANCE ANIMATION ; ============================================================================ advance_animation: move.l angle_accum,d0 addi.l #ANGLE_INC,d0 andi.l #$FFFF,d0 move.l d0,angle_accum move.l scale_accum,d0 addi.l #SCALE_INC,d0 andi.l #$FFFF,d0 move.l d0,scale_accum rts ; ============================================================================ ; CHECK IDCMP: returns d0=1 for Escape, otherwise 0 ; ============================================================================ check_idcmp: movem.l a1-a6,-(sp) moveq #0,d0 move.l d0,-(sp) ; result on stack movea.l window_ptr,a0 movea.l wd_UserPort(a0),a0 ; a0 = MsgPort movea.l _ExecBase,a6 .loop: jsr _LVOGetMsg(a6) tst.l d0 beq.s .no_more movea.l d0,a1 ; a1 = IntuiMessage move.l im_Class(a1),d1 move.w im_Code(a1),d2 jsr _LVOReplyMsg(a6) ; Check for RAWKEY + ESC cmpi.l #IDCMP_RAWKEY,d1 bne.s .loop cmpi.w #RAWKEY_ESC,d2 bne.s .loop move.l #1,(sp) ; set result = exit bra.s .loop ; drain remaining messages .no_more: move.l (sp)+,d0 ; get result movem.l (sp)+,a1-a6 rts ; ============================================================================ ; DATA (same section as code for single-hunk executable) ; ============================================================================ ; Library names intuition_name: dc.b 'intuition.library',0 cybergfx_name: dc.b 'cybergraphics.library',0 even ; Library bases _ExecBase: dc.l 0 _IntuitionBase: dc.l 0 _CyberGfxBase: dc.l 0 ; Pointers screen_ptr: dc.l 0 window_ptr: dc.l 0 texture_buf: dc.l 0 back_buf: dc.l 0 lock_handle: dc.l 0 display_id: dc.l 0 ; LockBitMapTagList output storage screen_vram: dc.l 0 screen_stride: dc.l 0 ; Animation state angle_accum: dc.l 0 scale_accum: dc.l 0 var_ca: dc.l 0 var_sa: dc.l 0 var_u0: dc.l 0 var_v0: dc.l 0 ; BestCModeIDTagList tags bestmode_tags: dc.l CYBRBIDTG_NominalWidth,640 dc.l CYBRBIDTG_NominalHeight,480 dc.l CYBRBIDTG_Depth,32 dc.l TAG_DONE ; OpenScreenTagList tags screen_tags: dc.l SA_Type,CUSTOMSCREEN dc.l SA_DisplayID scr_displayid_val: dc.l 0 ; patched at runtime dc.l SA_Width,RENDER_W dc.l SA_Height,RENDER_H dc.l SA_Depth,32 dc.l SA_Title dc.l scr_title dc.l SA_ShowTitle,0 dc.l SA_Quiet,1 dc.l TAG_DONE ; OpenWindowTagList tags window_tags: dc.l WA_CustomScreen win_screen_val: dc.l 0 ; patched at runtime dc.l WA_Width,RENDER_W dc.l WA_Height,RENDER_H dc.l WA_IDCMP,IDCMP_RAWKEY dc.l WA_Borderless,1 dc.l WA_Backdrop,1 dc.l WA_Activate,1 dc.l TAG_DONE ; LockBitMapTagList tags: ti_Data points to writable storage lbmi_tags: dc.l LBMI_BASEADDRESS dc.l screen_vram dc.l LBMI_BYTESPERROW dc.l screen_stride dc.l TAG_DONE scr_title: dc.b 'Rotozoomer HW',0 even ; ============================================================================ ; LOOKUP TABLES ; ============================================================================ ; Sine table: 256 entries, signed 16-bit ; Values: round(sin(i * 2*pi / 256) * 256) sine_table: dc.w 0,6,13,19,25,31,38,44,50,56,62,68,74,80,86,92 dc.w 98,104,109,115,121,126,132,137,142,147,152,157,162,167,172,177 dc.w 181,185,190,194,198,202,206,209,213,216,220,223,226,229,231,234 dc.w 237,239,241,243,245,247,248,250,251,252,253,254,255,255,256,256 dc.w 256,256,256,255,255,254,253,252,251,250,248,247,245,243,241,239 dc.w 237,234,231,229,226,223,220,216,213,209,206,202,198,194,190,185 dc.w 181,177,172,167,162,157,152,147,142,137,132,126,121,115,109,104 dc.w 98,92,86,80,74,68,62,56,50,44,38,31,25,19,13,6 dc.w 0,-6,-13,-19,-25,-31,-38,-44,-50,-56,-62,-68,-74,-80,-86,-92 dc.w -98,-104,-109,-115,-121,-126,-132,-137,-142,-147,-152,-157,-162,-167,-172,-177 dc.w -181,-185,-190,-194,-198,-202,-206,-209,-213,-216,-220,-223,-226,-229,-231,-234 dc.w -237,-239,-241,-243,-245,-247,-248,-250,-251,-252,-253,-254,-255,-255,-256,-256 dc.w -256,-256,-256,-255,-255,-254,-253,-252,-251,-250,-248,-247,-245,-243,-241,-239 dc.w -237,-234,-231,-229,-226,-223,-220,-216,-213,-209,-206,-202,-198,-194,-190,-185 dc.w -181,-177,-172,-167,-162,-157,-152,-147,-142,-137,-132,-126,-121,-115,-109,-104 dc.w -98,-92,-86,-80,-74,-68,-62,-56,-50,-44,-38,-31,-25,-19,-13,-6 ; Reciprocal table: 256 entries, unsigned 16-bit ; Values: round(256 / (0.5 + sin(i * 2*pi / 256) * 0.3)) recip_table: dc.w 512,505,497,490,484,477,471,464,458,453,447,441,436,431,426,421 dc.w 416,412,407,403,399,395,391,388,384,381,377,374,371,368,365,362 dc.w 359,357,354,352,350,348,345,343,342,340,338,336,335,333,332,331 dc.w 329,328,327,326,325,324,324,323,322,322,321,321,321,320,320,320 dc.w 320,320,320,320,321,321,321,322,322,323,324,324,325,326,327,328 dc.w 329,331,332,333,335,336,338,340,342,343,345,348,350,352,354,357 dc.w 359,362,365,368,371,374,377,381,384,388,391,395,399,403,407,412 dc.w 416,421,426,431,436,441,447,453,458,464,471,477,484,490,497,505 dc.w 512,520,528,536,544,553,561,571,580,589,599,610,620,631,642,653 dc.w 665,676,689,701,714,727,740,754,768,782,797,812,827,842,858,873 dc.w 889,905,922,938,955,972,988,1005,1022,1038,1055,1071,1087,1103,1119,1134 dc.w 1149,1163,1177,1190,1202,1214,1225,1235,1244,1252,1260,1266,1271,1275,1278,1279 dc.w 1280,1279,1278,1275,1271,1266,1260,1252,1244,1235,1225,1214,1202,1190,1177,1163 dc.w 1149,1134,1119,1103,1087,1071,1055,1038,1022,1005,988,972,955,938,922,905 dc.w 889,873,858,842,827,812,797,782,768,754,740,727,714,701,689,676 dc.w 665,653,642,631,620,610,599,589,580,571,561,553,544,536,528,520 ; ============================================================================ ; TEXTURE DATA ; ============================================================================ even texture_data: incbin "../assets/rotozoomtexture_hw_asm.raw" music_path: dc.b "sdk/examples/assets/music/chopper.ahx",0 even