chiark - git - mdw - ssr/blob - StraySrc/SapphToys/!ColDemo/s/hsv

   1 ;
   2 ; hsv.s
   3 ;
   4 ; HSV functions (TMA)
   5 ;
   6 ; © 1994 Straylight
   7 ;
   8
   9 ;----- Standard header ------------------------------------------------------
  10
  11                 GET     libs:header
  12                 GET     libs:swis
  13
  14 ;----- External dependencies ------------------------------------------------
  15
  16                 GET     sapphire:dbox
  17                 GET     sapphire:divide
  18                 GET     sapphire:fixedPt
  19                 GET     sapphire:screen
  20                 GET     sapphire:sqrt
  21
  22                 GET     sapphire:dbx.dbx
  23
  24                 GET     sapphire:string
  25                 GET     sapphire:note
  26
  27                 GET     sapphire:_cs.kernel
  28                 GET     sapphire:_cs.vars
  29
  30 ;----- Main code ------------------------------------------------------------
  31
  32                 AREA    |Sapphire$$Code|,CODE,READONLY
  33
  34 ; --- hsv_open ---
  35 ;
  36 ; On entry:     --
  37 ;
  38 ; On exit:      --
  39 ;
  40 ; Use:          Called by the colour picker
  41
  42                 EXPORT  hsv_open
  43 hsv_open        ROUT
  44
  45                 STMFD   R13!,{R1-R3,R14}        ;Stack the link register
  46                 ADR     R0,hsv_dbName           ;Point to dialogue box name
  47                 BL      dbox_create             ;Create the dialogue box
  48
  49         ; --- TEMPORARY CODE ---
  50
  51                 LDMVSFD R13!,{R1-R3,PC}         ;Return to caller
  52                 ADR     R1,hsv__dbh
  53                 MOV     R2,R10
  54                 MOV     R3,R12
  55                 BL      dbox_eventHandler
  56                 LDMVSFD R13!,{R1-R3,PC}         ;Return to caller
  57                 ADR     R1,hsv__dbxDef          ;Point to the control defn
  58                 BL      dbx_declare             ;Declare it to dbx nicely
  59
  60                 LDMFD   R13!,{R1-R3,PC}         ;Return to caller
  61
  62
  63 hsv_dbName      DCB     "hsv",0
  64
  65 hsv__dbxDef     CONTROL 0,hsvCircle,R10,0,0
  66                 ECTRL
  67                 DBXEND
  68
  69                 LTORG
  70
  71 hsv__dbh        ROUT
  72
  73                 CMP     R0,#csEvent__close      ;Is this a close event?
  74                 MOVNES  PC,R14                  ;No -- return then
  75                 STMFD   R13!,{R0,R14}           ;Save registers
  76                 MOV     R0,R9
  77                 BL      dbox_destroy
  78                 LDMFD   R13!,{R0,PC}^
  79
  80                 LTORG
  81
  82 ; --- hsv_plotCircle ---
  83 ;
  84 ; On entry:     R0 == x coord of centre of circle to plot
  85 ;               R1 == y coord of centre of circle to plot
  86 ;               R2 == x step (in OS units, must be power of 2)
  87 ;               R3 == y step (in OS units, must be power of 2)
  88 ;               R4 == value coordinate (in 16.16 form)
  89 ;               R5 == pointer to graphics rectangle block
  90 ;
  91 ; On exit:      --
  92 ;
  93 ; Use:          Plots an HSV colour circle at the position specified.
  94 ;               This should look really pretty as long as you're not using
  95 ;               RISC OS 2 :-(.
  96
  97                 EXPORT  hsv_plotCircle
  98 hsv_plotCircle  ROUT
  99
 100                 STMFD   R13!,{R0-R10,R12,R14}   ;Save a job lot of regs
 101                 MOV     R12,R5                  ;Keep pointer to graphics blk
 102
 103                 ; --- Set up the radius value ---
 104
 105                 MOV     R14,R4,LSR #9           ;Calculate the radius value
 106                 MUL     R10,R14,R14             ;Now square it and keep it
 107
 108                 ; --- Work out the pixel sizes ---
 109
 110                 BL      screen_getInfo          ;Find out about the screen
 111                 LDMIA   R0,{R6,R7}              ;Load the eign factors
 112                 MOV     R14,#1                  ;We're going to shift this
 113                 MOV     R6,R14,LSL R6           ;Calculate the x pixel size
 114                 MOV     R7,R14,LSL R7           ;And the y pixel size
 115                 STMFD   R13!,{R6,R7}            ;Save these for later use
 116
 117                 ; --- Start the main loop off ---
 118
 119                 LDR     R9,[R12,#12]            ;Get top of the rectangle
 120                 SUB     R9,R9,R1                ;Subtract the circle centre
 121                 CMP     R9,#127                 ;Is the rectangle too high?
 122                 MOVGT   R9,#127                 ;Yes -- start at circle top
 123                 SUB     R14,R3,#1               ;Turn ystep into bitmask
 124                 BIC     R9,R9,R14               ;And align to multiple nicely
 125
 126                 ; --- Get start x position into R1 ---
 127
 128                 LDR     R1,[R12,#0]             ;Get left hand side of area
 129                 LDR     R14,[R13,#8]            ;Load the centre position
 130                 SUB     R1,R1,R14               ;Subtract to get offset
 131                 CMP     R1,#-128                ;Is it too far to the left?
 132                 MOVLT   R1,#-128                ;Yes -- fix it up
 133                 SUB     R14,R2,#1               ;Turn xstep into bitmask
 134                 BIC     R1,R1,R14               ;Align to step value nicely
 135
 136                 ; --- Get finish x position into R4 ---
 137
 138                 LDR     R4,[R12,#8]             ;Get the right hand side pos
 139                 LDR     R0,[R13,#8]             ;Load the x centre position
 140                 SUB     R4,R4,R0                ;Convert to offset
 141                 CMP     R4,#128                 ;Is this off the right side?
 142                 MOVGT   R4,#128                 ;Yes -- stop being silly then
 143
 144                 ; --- And now get finish y position into R5 ---
 145
 146                 LDR     R5,[R12,#4]             ;Get the bottom pos
 147                 LDR     R0,[R13,#12]            ;Load the y centre position
 148                 SUB     R5,R5,R0                ;Convert to offset
 149                 SUB     R5,R5,R3                ;Get the bottom of the sqr
 150                 CMP     R5,#-128                ;Is this off the bottom?
 151                 MOVLT   R5,#-128                ;Yes -- don't be silly then
 152
 153                 ; --- Plot a row ---
 154
 155 00              MOV     R8,R1                   ;Start at beginning of row
 156
 157                 ; --- Plot this rectangle ---
 158
 159 01              LDMIA   R13,{R6,R7}             ;Load pixel widths and things
 160                 STMFD   R13!,{R1-R5,R8,R9}      ;Save some useful things
 161                 SUB     R4,R2,R6                ;xstep-dx
 162                 SUB     R5,R3,R7                ;ystep-dy
 163
 164                 ; --- Calculate minx and maxx for given rectangle ---
 165
 166                 MUL     R14,R9,R9               ;Get y^2
 167                 SUB     R6,R10,R14              ;Calculate minx
 168                 ADD     R0,R9,R5                ;y+ystep-dy
 169                 MUL     R14,R0,R0               ;(y+ystep-dy)^2
 170                 SUB     R7,R10,R14              ;Calculate maxx
 171
 172                 ; --- Calculate various square values of x ---
 173
 174                 MUL     R0,R8,R8                ;Get x^2
 175                 ADD     R14,R8,R2               ;Get x+xstep
 176                 MUL     R1,R14,R14              ;And square that too
 177                 CMP     R8,#0                   ;Is x negative
 178                 RSBLT   R0,R0,#0                ;Yes -- make R0 -ve
 179                 RSBLT   R1,R1,#0                ;...and make R1 -ve
 180
 181                 ; --- Swap minx and maxx if we need to ---
 182
 183                 MOV     R14,#0                  ;Clear our `swap' flag
 184                 CMP     R8,#0                   ;Is x < 0
 185                 EORGE   R14,R14,#1              ;No -- toggle swap flag
 186                 RSBLT   R6,R6,#0                ;Yes -- make it -ve
 187                 RSBLT   R7,R7,#0                ;...and that too
 188                 CMP     R9,#0                   ;Is y < 0
 189                 EORLT   R14,R14,#1              ;Yes -- toggle swap flag
 190                 TST     R14,#1                  ;Do we need to swap?
 191                 EORNE   R6,R6,R7                ;Yes -- swap them round
 192                 EORNE   R7,R6,R7
 193                 EORNE   R6,R6,R7
 194
 195                 ; --- Is the rectangle outside the circle ---
 196
 197                 CMP     R1,R6                   ;Is (x+xstep)^2<minx?
 198                 CMPLT   R8,#0                   ;Yes -- ensure x<0
 199                 BLT     %10hsv_plotCircle       ;It is -- plot a rectangle
 200                 CMP     R0,R7                   ;Is x^2>=maxx?
 201                 CMPGE   R8,#0                   ;Yes -- is x>=0
 202                 BLT     %20hsv_plotCircle       ;No -- Try an edge rectangle
 203
 204                 ; --- Plot a blank square ---
 205
 206 10              MOV     R0,#1                   ;Wimp colour 1
 207                 SWI     Wimp_SetColour          ;Set the colour
 208                 BL      hsv__plotRectangle      ;Plot the rectangle
 209                 B       %70hsv_plotCircle       ;And branch to the end
 210
 211                 ; --- Is the rectangle on the circle edge? ---
 212
 213 20              CMP     R8,#0                   ;Is x < 0?
 214                 CMPLT   R0,R7                   ;Is x^2<maxx?
 215                 BLT     %25hsv_plotCircle       ;Yes -- plot the circle
 216                 CMP     R8,#0                   ;Is x>=0
 217                 CMPGE   R1,R6                   ;Is (x+xstep)>=minx
 218                 BLT     %40hsv_plotCircle       ;No -- plot an entire square
 219
 220                 ; --- Plot an edge square then ---
 221
 222 25              MOV     R0,#1                   ;Wimp colour 1
 223                 SWI     Wimp_SetColour          ;Set the colour
 224                 BL      hsv__plotRectangle      ;Plot the rectangle
 225                 BL      hsv__setColour          ;Set the correct colour
 226                 ADD     R7,R9,R5                ;Our final loop value
 227                 ADD     R14,R13,#36             ;Point to centre coords
 228                 LDMIA   R14,{R3,R5}             ;Get the centre coordinates
 229
 230 30              MUL     R14,R9,R9               ;y^2
 231                 SUBS    R0,R10,R14              ;Get r^2-y^2
 232                 BLT     %35hsv_plotCircle       ;Yes -- go round loop again
 233         ;       BL      sqrt                    ;Calculate the square root
 234
 235                 CMP     R8,#0                   ;Is x<0?
 236                 RSBLT   R1,R0,#0                ;Yes -- get xstart pos
 237                 ADDLT   R6,R8,R4                ;...and xend position
 238                 MOVGE   R1,R8                   ;No -- this xstart
 239                 LDRGE   R6,[R13,#28]            ;...get dx
 240                 SUBGE   R6,R0,R6                ;...and calc xend pos
 241
 242                 CMP     R1,R6                   ;Is there anything to plot?
 243                 BGT     %35hsv_plotCircle       ;No -- skip this line out
 244                 ADD     R1,R1,R3                ;x0
 245                 ADD     R2,R9,R5                ;y0
 246                 MOV     R0,#4                   ;Move absolute
 247                 SWI     OS_Plot                 ;Do the move
 248                 MOV     R0,#5                   ;Plot solid line absolute
 249                 ADD     R1,R3,R6                ;x1
 250                 ADD     R2,R9,R5                ;y1
 251                 SWI     OS_Plot                 ;Do the move
 252
 253 35              LDR     R14,[R13,#32]           ;Get dy
 254                 ADD     R9,R9,R14               ;Increment y value
 255                 CMP     R9,R7                   ;Are we at the end?
 256                 BLE     %30hsv_plotCircle       ;And keep ploting lines
 257                 B       %70                     ;Finished this square
 258
 259                 ; --- Now plot an entire coloured square ---
 260
 261 40              BL      hsv__setColour          ;Set the colour
 262                 BL      hsv__plotRectangle      ;Plot it then
 263
 264                 ; --- Find which square to do next ---
 265
 266 70              LDMFD   R13!,{R1-R5,R8,R9}      ;Get back registers
 267
 268                 ADD     R8,R8,R2                ;Increment R8 nicely
 269                 CMP     R8,R4                   ;Have we finished a row?
 270                 BLT     %01hsv_plotCircle       ;No -- do some more then
 271
 272                 SUB     R9,R9,R3                ;Move down to the next row
 273                 CMP     R9,R5                   ;Have we finished it yet?
 274                 BGE     %00hsv_plotCircle       ;No -- do the next row
 275
 276                 ; --- We did it then! ---
 277
 278                 ADD     R13,R13,#8              ;Skip past variable area
 279                 LDMFD   R13!,{R0-R10,R12,PC}^   ;Jubilations and things
 280
 281                 LTORG
 282
 283 ; --- hsv__plotRectangle ---
 284 ;
 285 ; On entry:     R4 == width
 286 ;               R5 == height
 287 ;               R8 == x offset from centre
 288 ;               R9 == y offset from centre
 289 ;               R13+36 centre coordinates
 290 ;
 291 ; On exit:      R0-R2 corrupted
 292
 293 hsv__plotRectangle ROUT
 294
 295                 ADD     R0,R13,#36              ;Point to circle centre
 296                 LDMIA   R0,{R1,R2}              ;Load the coordinates
 297                 MOV     R0,#4                   ;Move cursor absolute
 298                 ADD     R1,R1,R8                ;To this x coord
 299                 ADD     R2,R2,R9                ;And this y coord
 300                 SWI     OS_Plot                 ;Do the move
 301                 MOV     R0,#97                  ;Rectangle fill relative
 302                 MOV     R1,R4                   ;This wide
 303                 MOV     R2,R5                   ;This high
 304                 SWI     OS_Plot                 ;Plot the rectangle
 305                 MOVS    PC,R14                  ;And return to caller
 306
 307                 LTORG
 308
 309 ; --- hsv__setColour ---
 310 ;
 311 ; On entry:     R0 == x coord
 312 ;               R1 == y coord
 313 ;               R10 == radius^2
 314 ;               R13+52 == value
 315 ;
 316 ; On exit:      --
 317
 318 hsv__setColour  ROUT
 319
 320                 STMFD   R13!,{R0-R4,R14}        ;Stack some registers
 321                 BL      fxp_pol                 ;Calculate hue
 322                 MOV     R3,R0                   ;Preserve angle
 323
 324                 MUL     R14,R1,R1               ;Get y^2
 325                 MUL     R0,R2,R2                ;Get x^2
 326                 ADD     R0,R0,R14               ;Add them
 327                 MOV     R1,R10                  ;Get radius^2
 328                 MOV     R0,R0,LSL#16            ;Prepare for division
 329                 CMP     R1,#0                   ;Will we divide by 0?
 330                 BLNE    div_round               ;No -- perform the division
 331                 MOVEQ   R0,#0                   ;Yes -- make it 0 for luck
 332                 MOV     R1,R0                   ;The saturation
 333                 MOV     R0,R3                   ;Get hue back
 334                 LDR     R2,[R13,#76]            ;Get value
 335                 BL      hsv_HSVToRGB            ;Convert to RGB
 336                 RSB     R0,R0,R0,LSL#8          ;Multiple by 255
 337                 RSB     R1,R1,R1,LSL#8          ;Multiple by 255
 338                 RSB     R2,R2,R2,LSL#8          ;Multiple by 255
 339                 AND     R0,R0,#&FF0000          ;Ensure it's 0-255
 340                 AND     R1,R1,#&FF0000          ;Ensure it's 0-255
 341                 AND     R2,R2,#&FF0000          ;Ensure it's 0-255
 342                 MOV     R0,R0,LSR#8             ;Set up red component
 343                 ORR     R0,R0,R1                ;And green component
 344                 ORR     R0,R0,R2,LSL#8          ;And finally blue
 345                 MOV     R14,R0                  ;Preserve R0
 346                 MOV     R3,#&100                ;The colourTrans flags
 347                 MOV     R4,#0                   ;GCOL action
 348                 SWI     XColourTrans_SetGCOL    ;Set the colour
 349                 MOVVS   R3,#0                   ;Try without dither
 350                 MOVVS   R0,R14                  ;Get colour back
 351                 SWIVS   ColourTrans_SetGCOL     ;Set the colour
 352
 353                 LDMFD   R13!,{R0-R4,PC}^        ;Return to caller
 354
 355                 LTORG
 356
 357 ; --- hsv__plot32k ---
 358 ;
 359 ; On entry:     R0 == left hand side of colour square to plot
 360 ;               R1 == bottom edge of colour square to plot
 361 ;               R2 == pointer to graphics window block
 362 ;               R3 == pointer to screen information block
 363 ;               R7 == unlimited minimum x position to plot
 364 ;               R8 == unlimited minimum y position to plot
 365 ;               R9 == unlimited maximum x position to plot
 366 ;               R10 == unlimited maximum y position to plot
 367 ;               On stack: saved {R0-R12,R14}
 368 ;
 369 ; On exit:      --
 370 ;
 371 ; Use:          Displays an HSV circle on the screen at a given location,
 372 ;               in a 16bpp mode, using direct screen access.
 373
 374 hsv__plot32k    ROUT
 375
 376                 ; --- Limit the relative box positions ---
 377
 378                 ADD     R4,R3,#screen_dx        ;Find the pixel positions
 379                 LDMIA   R4,{R4,R5}              ;Load them into registers
 380
 381                 CMP     R7,#0                   ;Is min x too small?
 382                 MOVLT   R7,#0                   ;Yes -- raise it to 0
 383                 CMP     R8,#0                   ;Is min y too small?
 384                 MOVLT   R8,#0                   ;Yes --- raise that too
 385                 CMP     R9,#256                 ;Is the max x too large?
 386                 MOVGT   R9,#256                 ;Yes -- reduce it then
 387                 CMP     R10,#256                ;Is the max y too large?
 388                 MOVGT   R10,#256                ;Yes -- reduce it then
 389                 SUB     R9,R9,R4                ;Make this inclusive
 390                 SUB     R10,R10,R5              ;Make this inclusive too
 391
 392                 ; --- Find address of thing on the screen ---
 393
 394                 MOV     R5,R7                   ;Remember left hand offset
 395                 MOV     R6,R10                  ;And right hand one
 396
 397                 SUB     R9,R9,R7                ;Work out width
 398                 SUB     R8,R10,R8               ;And height
 399                 ADD     R7,R7,R0                ;Work out left hand side
 400                 ADD     R10,R10,R1              ;And maximum y
 401
 402                 SUB     R13,R13,#20             ;Space for our vdu vars
 403                 ADR     R0,hsv__vduVars         ;Point to the var numbers
 404                 MOV     R1,R13                  ;Point to our output block
 405                 SWI     OS_ReadVduVariables     ;Get the values nicely
 406
 407                 ; --- Convert things to pixels sizes ---
 408
 409                 LDMIA   R13!,{R3,R4}            ;Load out eig factors
 410                 MOV     R7,R7,LSR R3            ;Convert left hand side
 411                 MOV     R8,R8,LSR R4            ;And height
 412                 MOV     R9,R9,LSR R3            ;The width too
 413                 MOV     R10,R10,LSR R4          ;And the top coord
 414
 415                 LDMIA   R13!,{R0,R1,R2}         ;Load other vdu vars
 416                 SUB     R14,R1,R10              ;Shift origin to top left
 417                 MLA     R0,R14,R2,R0            ;Work out address of row
 418                 ADD     R12,R0,R7,LSL #1        ;Work out left address
 419                 ADD     R11,R12,R9,LSL #1       ;Work out right hand side too
 420                 MOV     R9,R2                   ;Put scan line width in R9
 421                 MOV     R10,R8                  ;And height in R10
 422
 423                 SUB     R8,R5,#128              ;Work out x start position
 424                 SUB     R7,R6,#128              ;And y start position
 425
 426                 MOV     R14,#1                  ;Get a useful value
 427                 MOV     R6,R14,LSL R3           ;x step
 428                 MOV     R5,R14,LSL R4           ;y step
 429                 MOV     R4,R8                   ;Initial x value
 430                 MOV     R3,#&10000              ;Value
 431
 432                 ; --- Plot the circle then ---
 433
 434 10hsv__plot32k  MOV     R0,#0                   ;Clear buffer register
 435                 MOV     R1,R12                  ;Get the current address
 436
 437                 BL      hsv__getColour32        ;Get the colour then
 438
 439                 TST     R1,#2                   ;Is this address aligned?
 440                 BEQ     %20hsv__plot32k         ;Yes -- start at main loop
 441                 LDR     R14,[R1,#-2]            ;No -- load word from here
 442                 MOV     R14,R14,LSL #16         ;Shift all the way up
 443                 ORR     R14,R0,R14,LSR #16      ;Build the replacement word
 444                 STR     R14,[R1,#-2]            ;And store in frame buffer
 445                 B       %25hsv__plot32k         ;Jump to end of loop
 446
 447                 ; --- Now the main plotting loop ---
 448
 449 20hsv__plot32k  TST     R1,#2                   ;Is this an odd address?
 450                 STRNE   R0,[R1,#-2]             ;Yes -- done both half words
 451
 452 25hsv__plot32k  ADD     R1,R1,#2                ;Move onto next pixel
 453                 ADD     R8,R8,R6                ;Increment x position
 454                 CMP     R1,R11                  ;Are we at the line end?
 455                 BLLS    hsv__getColour32        ;No -- get the colour then
 456                 BLS     %20hsv__plot32k         ;...and go round for more
 457
 458                 ; --- We've finished; do we have a half word left over? ---
 459
 460 30hsv__plot32k  TST     R1,#2                   ;Is the address odd?
 461                 BEQ     %35hsv__plot32k         ;No -- jump ahead
 462                 LDR     R14,[R1,#-2]            ;Yes -- read old word
 463                 MOV     R0,R0,LSR #16           ;Put buffer value in low hw
 464                 MOV     R14,R14,LSR #16         ;Shift down screen value too
 465                 ORR     R14,R0,R14,LSL #16      ;Build up correct word
 466                 STR     R14,[R1,#-2]            ;Store this word away
 467
 468                 ; --- Move onto the next row ---
 469
 470 35hsv__plot32k  ADD     R12,R12,R9              ;Move left address down
 471                 ADD     R11,R11,R9              ;And the right address
 472                 SUB     R7,R7,R5                ;Decrement the y position
 473                 MOV     R8,R4                   ;Initial start x position
 474                 SUBS    R10,R10,#1              ;Decrement the line count
 475                 BCS     %10hsv__plot32k         ;And keep on going
 476                 LDMFD   R13!,{R0-R12,PC}^       ;Return to caller
 477
 478                 LTORG
 479
 480 hsv__vduVars    DCD     4,5                     ;X and Y eigen factors
 481                 DCD     149                     ;Start of display memory
 482                 DCD     12                      ;How high is the screen
 483                 DCD     6                       ;Width of scan line in pixels
 484                 DCD     -1
 485
 486 ; --- hsv__getColour32 ---
 487 ;
 488 ; On entry:     R0 == colour word so far
 489 ;               R1 == current screen address
 490 ;               R3 == value (16.16)
 491 ;               R7 == y position
 492 ;               R8 == x position
 493 ;
 494 ; On exit:      R0 == updated colour word
 495 ;
 496 ;
 497 ; Use:          Determines the colour of the pixel at the given position
 498 ;               for a 32k colour mode
 499
 500 hsv__getColour32 ROUT
 501
 502                 STMFD   R13!,{R1-R5,R14}        ;Stack some regsiters
 503
 504                 MOV     R5,R0                   ;Look after old colour
 505                 MUL     R2,R7,R7                ;Get y^2
 506                 MUL     R14,R8,R8               ;Get x^2
 507                 ADD     R2,R2,R14               ;Get x^2+y^2
 508                 CMP     R2,#&4000               ;Is this in range?
 509                 BCS     %50hsv__getColour32     ;No -- do really clever stuff
 510
 511                 MOV     R0,R8                   ;Put x position in R0
 512                 MOV     R1,R7                   ;And x position in R1
 513                 BL      fxp_pol                 ;Calculate hue
 514                 MOV     R4,R0                   ;Preserve angle
 515
 516                 MOV     R0,R2                   ;x^2 + y^2
 517                 MOV     R1,#&4000               ;Get radius^2
 518                 MOV     R0,R0,LSL#16            ;Prepare for division
 519                 CMP     R1,#0                   ;Will we divide by 0?
 520                 BLNE    div_round               ;No -- perform the division
 521                 MOVEQ   R0,#0                   ;Yes -- make it 0 for luck
 522
 523                 MOV     R1,R0                   ;The saturation
 524
 525                 MOV     R0,R4                   ;Get hue back
 526                 MOV     R2,R3                   ;Put value in R2
 527                 BL      hsv_HSVToRGB            ;Convert to RGB
 528
 529                 RSB     R0,R0,R0,LSL#5          ;Multiple by 31
 530                 RSB     R1,R1,R1,LSL#5          ;Multiple by 31
 531                 RSB     R2,R2,R2,LSL#5          ;Multiple by 31
 532                 AND     R0,R0,#&1F0000          ;Ensure it's 0-31
 533                 AND     R1,R1,#&1F0000          ;Ensure it's 0-31
 534                 AND     R2,R2,#&1F0000          ;Ensure it's 0-31
 535
 536                 ORR     R14,R0,R1,LSL #5        ;Red and green
 537                 ORR     R14,R14,R2,LSL #10      ;...blue
 538
 539                 ORR     R0,R14,R5,LSR #16       ;Return colour number
 540                 LDMFD   R13!,{R1-R5,PC}^        ;Return to caller
 541
 542                 ; --- Position is out of range ---
 543
 544 50              LDR     R14,[R1,#0]             ;Load halfword at address
 545                 MOV     R14,R14,LSL #16         ;Put it into top halfword
 546                 ORR     R0,R14,R5,LSR #16       ;Build up new colour value
 547                 LDMFD   R13!,{R1-R5,PC}^        ;And return to caller
 548
 549                 LTORG
 550
 551 ; --- hsv__plot16m ---
 552 ;
 553 ; On entry:     R0 == left hand side of colour square to plot
 554 ;               R1 == bottom edge of colour square to plot
 555 ;               R2 == pointer to graphics window block
 556 ;               R3 == pointer to screen information block
 557 ;               R7 == unlimited minimum x position to plot
 558 ;               R8 == unlimited minimum y position to plot
 559 ;               R9 == unlimited maximum x position to plot
 560 ;               R10 == unlimited maximum y position to plot
 561 ;               On stack: saved {R0-R12,R14}
 562 ;
 563 ; On exit:      --
 564 ;
 565 ; Use:          Displays an HSV circle on the screen at a given location,
 566 ;               in a 32bpp mode, using direct screen access.
 567
 568 hsv__plot16m    ROUT
 569
 570                 ; --- Limit the relative box positions ---
 571
 572                 ADD     R4,R3,#screen_dx        ;Find the pixel positions
 573                 LDMIA   R4,{R4,R5}              ;Load them into registers
 574
 575                 CMP     R7,#0                   ;Is min x too small?
 576                 MOVLT   R7,#0                   ;Yes -- raise it to 0
 577                 CMP     R8,#0                   ;Is min y too small?
 578                 MOVLT   R8,#0                   ;Yes --- raise that too
 579                 CMP     R9,#256                 ;Is the max x too large?
 580                 MOVGT   R9,#256                 ;Yes -- reduce it then
 581                 CMP     R10,#256                ;Is the max y too large?
 582                 MOVGT   R10,#256                ;Yes -- reduce it then
 583                 SUB     R9,R9,R4                ;Make this inclusive
 584                 SUB     R10,R10,R5              ;Make this inclusive too
 585
 586                 ; --- Find address of thing on the screen ---
 587
 588                 MOV     R5,R7                   ;Remember left hand offset
 589                 MOV     R6,R10                  ;And right hand one
 590
 591                 SUB     R9,R9,R7                ;Work out width
 592                 SUB     R8,R10,R8               ;And height
 593                 ADD     R7,R7,R0                ;Work out left hand side
 594                 ADD     R10,R10,R1              ;And maximum y
 595
 596                 SUB     R13,R13,#20             ;Space for our vdu vars
 597                 ADR     R0,hsv__vduVars         ;Point to the var numbers
 598                 MOV     R1,R13                  ;Point to our output block
 599                 SWI     OS_ReadVduVariables     ;Get the values nicely
 600
 601                 ; --- Convert things to pixels sizes ---
 602
 603                 LDMIA   R13!,{R3,R4}            ;Load out eig factors
 604                 MOV     R7,R7,LSR R3            ;Convert left hand side
 605                 MOV     R8,R8,LSR R4            ;And height
 606                 MOV     R9,R9,LSR R3            ;The width too
 607                 MOV     R10,R10,LSR R4          ;And the top coord
 608
 609                 LDMIA   R13!,{R0,R1,R2}         ;Load other vdu vars
 610                 SUB     R14,R1,R10              ;Shift origin to top left
 611                 MLA     R0,R14,R2,R0            ;Work out address of row
 612                 ADD     R12,R0,R7,LSL #2        ;Work out left address
 613                 ADD     R11,R12,R9,LSL #2       ;Work out right hand side too
 614                 MOV     R9,R2                   ;Put scan line width in R9
 615                 MOV     R10,R8                  ;And height in R10
 616
 617                 SUB     R8,R5,#128              ;Work out x start position
 618                 SUB     R7,R6,#128              ;And y start position
 619
 620                 MOV     R14,#1                  ;Get a useful value
 621                 MOV     R6,R14,LSL R3           ;x step
 622                 MOV     R5,R14,LSL R4           ;y step
 623                 MOV     R4,R8                   ;Initial x value
 624                 MOV     R3,#&10000              ;Value
 625
 626                 ; --- Plot the circle then ---
 627
 628 10hsv__plot16m  MOV     R1,R12                  ;Get the current address
 629
 630                 ; --- Now the main plotting loop ---
 631
 632 20hsv__plot16m  BL      hsv__getColour16        ;Get the colour then
 633                 STR     R0,[R1],#4              ;Yes -- done both half words
 634
 635 25hsv__plot16m  ADD     R8,R8,R6                ;Increment x position
 636                 CMP     R1,R11                  ;Are we at the line end?
 637                 BLS     %20hsv__plot16m         ;...and go round for more
 638
 639                 ; --- Move onto the next row ---
 640
 641 30hsv__plot16m  ADD     R12,R12,R9              ;Move left address down
 642                 ADD     R11,R11,R9              ;And the right address
 643                 SUB     R7,R7,R5                ;Decrement the y position
 644                 MOV     R8,R4                   ;Initial start x position
 645                 SUBS    R10,R10,#1              ;Decrement the line count
 646                 BCS     %10hsv__plot16m         ;And keep on going
 647
 648                 LDMFD   R13!,{R0-R12,PC}^       ;Return to caller
 649
 650                 LTORG
 651
 652 ; --- hsv__getColour16--
 653 ;
 654 ; On entry:     R3 == value (16.16)
 655 ;               R7 == y position
 656 ;               R8 == x position
 657 ;
 658 ; On exit:      R0 == updated colour word
 659 ;
 660 ; Use:          Determines the colour of the pixel at the given position
 661 ;               for a 32m colour mode
 662
 663 hsv__getColour16 ROUT
 664
 665                 STMFD   R13!,{R1-R4,R14}        ;Stack some regsiters
 666
 667                 MUL     R2,R7,R7                ;Get y^2
 668                 MUL     R4,R8,R8                ;Get x^2
 669                 ADD     R2,R2,R4                ;Get x^2+y^2
 670                 CMP     R2,#&4000               ;Is this in range?
 671                 LDRCS   R0,[R1,#0]              ;No -- load previous colour
 672                 LDMCSFD R13!,{R1-R4,PC}^        ;And return to caller
 673
 674                 MOV     R0,R8                   ;Put x position in R0
 675                 MOV     R1,R7                   ;And x position in R1
 676                 BL      fxp_pol                 ;Calculate hue
 677                 MOV     R4,R0                   ;Preserve angle
 678
 679                 MOV     R0,R2                   ;x^2 + y^2
 680                 MOV     R1,#&4000               ;Get radius^2
 681                 MOV     R0,R0,LSL#16            ;Prepare for division
 682                 CMP     R1,#0                   ;Will we divide by 0?
 683                 BLNE    div_round               ;No -- perform the division
 684                 MOVEQ   R0,#0                   ;Yes -- make it 0 for luck
 685
 686                 MOV     R1,R0                   ;The saturation
 687                 MOV     R0,R4                   ;Get hue back
 688                 MOV     R2,R3                   ;Put value in R2
 689                 BL      hsv_HSVToRGB            ;Convert to RGB
 690
 691                 RSB     R0,R0,R0,LSL#8          ;Multiple by 255
 692                 RSB     R1,R1,R1,LSL#8          ;Multiple by 255
 693                 RSB     R2,R2,R2,LSL#8          ;Multiple by 255
 694                 AND     R0,R0,#&FF0000          ;Ensure it's 0-255
 695                 AND     R1,R1,#&FF0000          ;Ensure it's 0-255
 696                 AND     R2,R2,#&FF0000          ;Ensure it's 0-255
 697
 698                 ORR     R0,R2,R0,LSR #16        ;Get red & blue components
 699                 ORR     R0,R0,R1,LSR #8         ;And green
 700
 701                 LDMFD   R13!,{R1-R4,PC}^        ;Return to caller
 702
 703                 LTORG
 704
 705 ; --- hsv__plotCircle ---
 706 ;
 707 ; On entry:     R0 == left hand side of colour square to plot
 708 ;               R1 == bottom edge of colour square to plot
 709 ;               R2 == pointer to graphics window block
 710 ;
 711 ; On exit:      --
 712 ;
 713 ; Use:          Dispatches to the most suitable hsv plotting routine for
 714 ;               the given mode.
 715
 716 hsv__plotCircle ROUT
 717
 718                 STMFD   R13!,{R0-R12,R14}       ;Save lots of registers
 719
 720                 ; --- Work out the minimum coordinates ---
 721
 722                 LDMIA   R2,{R7,R8,R9,R10}       ;Load the coordinates out
 723                 SUB     R7,R7,R0                ;Translate min x to relative
 724                 SUB     R8,R8,R1                ;Translate min y too
 725                 SUB     R9,R9,R0                ;Translate max x too
 726                 SUB     R10,R10,R1              ;Translate max y
 727
 728                 ; --- Try to dispatch ---
 729
 730                 MOV     R4,R0                   ;Look after left hand side
 731
 732                 BL      screen_getInfo          ;Get screen info block
 733                 MOV     R3,R0                   ;Put it in R3
 734                 MOV     R0,R4                   ;And get left hand side back
 735                 LDR     R14,[R3,#screen_bpp]    ;Load current bits/pixel
 736                 CMP     R14,#16                 ;Is this a 32K mode?
 737                 BEQ     hsv__plot32k            ;Yes -- well, go to it
 738                 CMP     R14,#32                 ;Is this a 32K mode?
 739                 BEQ     hsv__plot16m
 740
 741                 LDMFD   R13!,{R0-R12,PC}^       ;Return to caller
 742
 743                 LTORG
 744
 745 ; --- The dbx control ---
 746
 747 hsvCircle       ROUT
 748
 749                 DCD     0,0
 750                 DCD     dbxMask_redraw+dbxMask_click
 751
 752                 CMP     R0,#dbxEvent_click
 753                 BEQ     %10
 754
 755                 STMFD   R13!,{R0-R2,R10,R14}    ;Stack some registers
 756                 MOV     R10,R8                  ;Put dbox data in R10
 757                 MOV     R0,R2                   ;Put bottom left in R0
 758                 MOV     R1,R3                   ;And bottom right in R1
 759                 MOV     R2,R6                   ;Put graphics rectangle in R2
 760                 BL      hsv__plotCircle         ;Plot the circle then
 761                 LDMFD   R13!,{R0-R2,R10,PC}^    ;Return to caller
 762
 763 10              STMFD   R13!,{R0-R5,R14}
 764                 MOV     R0,R10
 765                 BL      dbx_controlBBox
 766                 SUB     R4,R4,R2
 767                 SUB     R5,R5,R3
 768                 ADD     R0,R2,R4,LSR #1
 769                 ADD     R1,R3,R5,LSR #1
 770                 MOV     R2,#128
 771                 SWI     Constrain_Disc
 772                 LDMFD   R13!,{R0-R5,PC}^
 773
 774                 LTORG
 775
 776                 [ 0=1
 777 ; --- sqrt ---
 778 ;
 779 ; On entry:     R0 == number to find square root of
 780 ;
 781 ; On exit:      R0 == square root of number passed in
 782 ;
 783 ; Use:          Calculates the square root of the number passed to
 784 ;               the nearest integer
 785
 786 sqrt            ROUT
 787
 788                 STMFD   R13!,{R1-R5,R14}        ;Stack some registers
 789                 MOV     R4,R0,LSR#2             ;Get an approximation
 790                 MOV     R3,#-1                  ;The old value
 791                 MOV     R2,R0                   ;Keep this value
 792                 MOV     R5,#10                  ;Maximum number of iterations
 793
 794 00sqrt          MOV     R0,R2,ASR #1            ;Divide number to squareroot
 795                 MOVS    R1,R4                   ;By 2*our approximation
 796                 BEQ     %01sqrt                 ;Divide by 0 -- leave now
 797                 BL      div_round               ;Round result to nearest
 798                 ADD     R4,R0,R4,ASR #1         ;Add this to x/2
 799
 800                 SUBS    R5,R5,#1                ;Decrement iteration count
 801                 BEQ     %01sqrt                 ;Too low -- skip to end
 802
 803                 CMP     R4,R3                   ;Is solution same as last?
 804                 MOVNE   R3,R4                   ;No -- remember result
 805                 BNE     %00sqrt                 ;...and keep trying
 806
 807 01sqrt          MOV     R0,R4                   ;Return root in R0
 808                 LDMFD   R13!,{R1-R5,PC}^        ;Return to caller
 809
 810                 LTORG
 811                 ]
 812
 813 ; --- HSV -> RGB conversion ---
 814
 815 ; --- div60 ---
 816 ;
 817 ; On entry:     R0 == integer to divide
 818 ;
 819 ; On exit:      R0 == quotient after division by 60
 820 ;               R1 == remainder after division by 60
 821 ;
 822 ; Use:          Divides an integer very quickly by 60.
 823 ;
 824 ; [Generated by Straylight divc]
 825
 826 div60           ROUT
 827
 828                 STMFD R13!,{R2,R14}
 829                 MOVS R2,R0
 830                 RSBMI R0,R0,#0
 831                 MOV R1,R0
 832
 833                 ADD R0,R0,R0,LSR#4
 834                 ADD R0,R0,R0,LSR#8
 835                 ADD R0,R0,R0,LSR#16
 836
 837                 MOV R0,R0,LSR #6
 838
 839                 RSB R14,R0,R0,LSL#4
 840                 MOV R14,R14,LSL#2
 841
 842                 SUB R1,R1,R14
 843                 SUBS R1,R1,#60
 844                 ADDGE R0,R0,#1
 845                 ADDLT R1,R1,#60
 846
 847                 CMP R2,#0
 848                 RSBMI R0,R0,#0
 849                 RSBMI R1,R1,#0
 850                 LDMFD R13!,{R2,PC}^
 851
 852                 LTORG
 853
 854 ; --- hsv_HSVToRGB ---
 855 ;
 856 ; On entry:     R0 == hue
 857 ;               R1 == saturation
 858 ;               R2 == value
 859 ;
 860 ; On exit:      R0 == red
 861 ;               R1 == green
 862 ;               R2 == blue
 863 ;
 864 ; Use:          Convert a colour in HSV to the equivalent in RGB notation.
 865 ;               All number are taken in 16.16 fixed point form. RGB values
 866 ;               range from 0 to 1 on output.
 867
 868 hsv_HSVToRGB    ROUT
 869
 870                 STMFD   R13!,{R3-R7,R14}        ;Stack some registers
 871
 872                 CMP     R0,#(360<<16)           ;Is hue 360?
 873                 MOVEQ   R0,#0                   ;Yes -- make it 0
 874
 875                 MOV     R3,R1                   ;Put saturation in R3
 876                 BL      div60                   ;Divide hue by 60
 877                 BIC     R1,R0,#&FF0000          ;Get fractional part in R1
 878                 MOV     R0,R0,LSR#16            ;And integer part in R0
 879
 880                 MOV     R4,R2,LSR#8             ;For multiplication
 881                 RSB     R5,R3,#1<<16            ;1-saturation (16.16 form)
 882                 MOV     R5,R5,LSR#8             ;Shift for division
 883                 MUL     R5,R4,R5                ;Minimum=value*(1-saturation)
 884                 MOV     R14,R3,LSR#8            ;Saturation >> 8
 885                 MOV     R6,R1,LSR#8             ;Fractional >> 8
 886                 MUL     R6,R14,R6               ;Saturation*fractional
 887                 RSB     R6,R6,#1<<16            ;1-(previous result)
 888                 MOV     R6,R6,LSR#8             ;Prepare for multiplication
 889                 MUL     R6,R4,R6                ;Inverse1=value*(prev result)
 890                 RSB     R7,R1,#1<<16            ;1-fractional
 891                 MOV     R7,R7,LSR#8             ;Prepare for multiplication
 892                 MUL     R7,R14,R7               ;Saturation*(1-fractional)
 893                 RSB     R7,R7,#1<<16            ;1-(sat*(1-fractional))
 894                 MOV     R7,R7,LSR#8             ;Prepare for multiplication
 895                 MUL     R7,R4,R7                ;Value*(1-(sat*(1-frac)))
 896
 897                 ; --- Find out which section number we are in ---
 898
 899                 CMP     R0,#0                   ;Section 0?
 900                 BNE     %10hsv_HSVToRGB         ;No -- try next one
 901                 MOV     R0,R2                   ;Red = value
 902                 MOV     R1,R7                   ;Green = inverse2
 903                 MOV     R2,R5                   ;Blue = minimum
 904                 LDMFD   R13!,{R3-R7,PC}^        ;Return to caller
 905
 906 10hsv_HSVToRGB  CMP     R0,#1                   ;Section 1?
 907                 BNE     %20hsv_HSVToRGB         ;No -- try next one
 908                 MOV     R0,R6                   ;Red = inverse1
 909                 MOV     R1,R2                   ;Green = value
 910                 MOV     R2,R5                   ;Blue = minimum
 911                 LDMFD   R13!,{R3-R7,PC}^        ;Return to caller
 912
 913 20hsv_HSVToRGB  CMP     R0,#2                   ;Section 2?
 914                 BNE     %30hsv_HSVToRGB         ;No -- try next one
 915                 MOV     R0,R5                   ;Red = minimum
 916                 MOV     R1,R2                   ;Green = value
 917                 MOV     R2,R7                   ;Blue = inverse2
 918                 LDMFD   R13!,{R3-R7,PC}^        ;Return to caller
 919
 920 30hsv_HSVToRGB  CMP     R0,#3                   ;Section 3?
 921                 BNE     %40hsv_HSVToRGB         ;No -- try next one
 922                 MOV     R0,R5                   ;Red = minimum
 923                 MOV     R1,R6                   ;Green = inverse1
 924                 LDMFD   R13!,{R3-R7,PC}^        ;Return to caller
 925
 926 40hsv_HSVToRGB  CMP     R0,#4                   ;Section 0?
 927                 BNE     %50hsv_HSVToRGB         ;No -- try next one
 928                 MOV     R0,R7                   ;Red = inverse2
 929                 MOV     R1,R5                   ;Green = minimum
 930                 LDMFD   R13!,{R3-R7,PC}^        ;Return to caller
 931
 932 50hsv_HSVToRGB  CMP     R0,#5                   ;Section 0?
 933                 BNE     %60hsv_HSVToRGB         ;No -- try next one
 934                 MOV     R0,R2                   ;Red = value
 935                 MOV     R1,R5                   ;Green = minimum
 936                 MOV     R2,R6                   ;Blue = inverse1
 937                 LDMFD   R13!,{R3-R7,PC}^        ;Return to caller
 938
 939 60hsv_HSVToRGB  ADR     R0,convert__error       ;Point to the error message
 940                 SWI     OS_GenerateError        ;And generate an error
 941
 942 convert__error  DCD     1
 943                 DCB     "Fatal error: hsv_HSVToRGB -- section >5 reached",0
 944
 945                 LTORG
 946
 947 ;----- Workspace layout -----------------------------------------------------
 948
 949                 AREA    |Sapphire$$LibData|,CODE,READONLY
 950
 951                 DCD     0
 952                 DCD     0
 953                 DCD     0
 954                 DCD     0
 955
 956 ;-- That's all, folks -------------------------------------------------------
 957
 958                 END