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Text File | 1996-02-02 | 20.1 KB | 462 lines

; \|/ ; O O ; --------------------------------oOO--U--OOo-------------------------------- ; | | ; | Randomly Shaded Splines (RSS) Shape Blending. | ; | By Alain BROBECKER and Frederic ELISEI. | ; | (Baah and Armoric of Arm's Tech) | ; | Sept-Oct 95 | ; --------------------------------------------------------------------------- ; ; The source code is separated in three parts, which are... ; - the main demo. (Shape blending between splines) ; - filaments code generation. ; - routine which draws a RSS. ; ; The main part is, as usual not all that interesting. The main idea ; behind it is a linear interpolation between the control brows of the ; different splines composing the objects. I must admit that this shape ; blending is totally user defined. (Look at RSS_Ed) ; The intersting idea in here is to draw a spline with a fixed amount of ; random shadedots around each of the points in the spline. My first version ; was totally realtime, but I spent a week-end at ArmOric' s house and he ; gave me the idea to use generated code for each random shadedots filament. ; ; >-------------------------------------------------------------------------< ; The full credits are going like this... ; - Idea and coding by Baah / Arm' s Tech. ; - Generated code idea by Armoric / Arm's Tech. ; - Spline rout by Baah, with inspiration from Jan / BASS. #set rss_shift=6 ; premul factor=n. #set rss_nb_pts=129 ; nb of points in the spline=1+2^(n+1). ;#set rss_time = 300 ; Time a shape stays on screen. #set rss_splines_nb = 16 ; Nb of splines per shape. #set rss_images_nb = 7 ; Nb of successive shapes. #set rss_routs_nb = 32 ; Nb of filaments routines to generate/2. #set rss_nb_rnd = 13 ; Nb of points drawn per generated rout. ;**************************************************************************** ;***** ***** ;***** RSS Shape Blending ***** ;***** ***** ;**************************************************************************** ; This is the part of the proggy which actually displays the forms on the ; screen, with shape blending between two shapes. It is not very hard to ; understand, so I won' t talk more here. ; Parameter for this demo part.... ; r0 = adress of a megabuffer used for creation of the generated code. .rss_part stmfd r13!,{r0-r12,r14} str r0,_megabuffer_ad ; Generate code for the filaments. add r0,r0,#rss_nb_pts*8 bl rss_generate_code adr r2,_rss_colors ; Change colors. bl set_palette ._shape_blending mov r0,#64 ; Nb of steps for one shape blending. str r0,_blend_counter ._blend_one_frame bl wait_and_swap ; Wait vsync, swap screens, r0=workscreen. mov r1,#&ff bl clear_mode9 ; Clear screen. adr r1,_animation ; r1=adress of current shape. ldr r2,_current_inc_ad ; r2=adress of current increments. mov r14,#rss_splines_nb ; Nb of splines to blend. ._blend_one_spline ldmia r1,{r3-r6} ; The 'shape blending' is in fact ldmia r2!,{r7-r10} ; a stupid linear interpolation between add r3,r3,r7 ; the control brows of two images. add r4,r4,r8 add r5,r5,r9 add r6,r6,r10 stmia r1!,{r3-r6} ldmia r1,{r3-r6} ldmia r2!,{r7-r10} add r3,r3,r7 add r4,r4,r8 add r5,r5,r9 add r6,r6,r10 stmia r1!,{r3-r6} subS r14,r14,#1 ; One spline 'blended'. bNE _blend_one_spline ; Time to draw the image on screen. sub r2,r1,#32*rss_splines_nb ; r2 points on current shape. ldr r10,_megabuffer_ad ; A buffer needed by the RSS routine. add r1,r10,#rss_nb_pts*8 ; r1 points on the filaments routines. mov r12,#rss_splines_nb ; Nb of splines to draw. ._blending_draw bl random_shade_spline add r2,r2,#8*4 ; Next spline coords. subS r12,r12,#1 ; It was last spline? bNE _blending_draw ldr r0,_blend_counter ; r0=nb of times still to blend. subS r0,r0,#1 strNE r0,_blend_counter bNE _blend_one_frame ; Prepare things for next shape blending. ._next_image ldr r0,_current_inc_ad add r0,r0,#32*rss_splines_nb str r0,_current_inc_ad ldr r0,_image_counter subS r0,r0,#1 cmp r0,#1 ldmLEfd r13!,{r0-r12,pc} ; Quit if it was last image. str r0,_image_counter ; Ok, we had better let the shape as is for some time, else the demolovers ; won' t be able to look at the wonderfull graphics. bl fix_time ._wait_one_frame bl wait_and_swap ; Wait vsync, swap screens, r0=workscreen. mov r1,#&ff bl clear_mode9 ; Clear screen. ldr r10,_megabuffer_ad ; A buffer needed by the RSS routine. add r1,r10,#rss_nb_pts*8 ; r1 points on the routines. adr r2,_animation mov r12,#rss_splines_nb ; Nb of splines to draw. ._wait_draw bl random_shade_spline add r2,r2,#8*4 ; Next spline coords. subS r12,r12,#1 ; It was last spline? bNE _wait_draw bl read_time ; r0=time elapsed. cmp r0,#rss_time bLE _wait_one_frame b _shape_blending ; =========================================================================== ; = = ; = MAIN DATAS = ; = = ; =========================================================================== ._rss_colors dcb &ff,&ff,&aa,&ff,&ee,&88,&ff,&dd,&66,&ff,&cc,&44 dcb &ff,&bb,&22,&ff,&aa,&00,&ee,&88,&00,&dd,&66,&00 dcb &cc,&44,&00,&bb,&22,&00,&aa,&00,&00,&88,&00,&00 dcb &66,&00,&00,&44,&00,&00,&22,&00,&00,&00,&00,&00 ._megabuffer_ad dcd 0 ._animation incbin RSS_Ed.RSS_anim ._blend_counter dcd 0 ._image_counter dcd rss_images_nb ._current_inc_ad dcd _animation+32*rss_splines_nb ;**************************************************************************** ;***** ***** ;***** Code Generator ***** ;***** ***** ;**************************************************************************** ; ; This routine creates a certain amount of routine which are drawing random ; filaments. This allows fast shading (on Arm2 it proves much faster) because ; we don' t need to perform the random walk of the filament in realtime, but ; instead we randomly choose a filament routine. Also, when we shade pixel ; we exactly know where it is in the byte, and it is much easier. (At first ; I was using a shadedot routine accessing to longwords, with lotsa masking ; and the like) So the generated code is a succession of... ; x even ldrB r6,[r7,#offset] ; Load byte. ; tst r6,#&f ; 4 lowerbits of r1=0? ; subNE r6,r6,#1 ; No, then shade the pixie. ; strB r6,[r7,#offset] ; And save modified byte. ; x odd ldrB r6,[r7,#offset] ; Load byte. ; subS r6,r6,#1<<4 ; Shade pixel in the 4 upperbits. ; strPLB r6,[r7,#offset] ; If pixel color>=0, save byte. ; ; As I said earlier the idea of generating code was brought up by ArmOric. ; He told it to me, and after the night we both came with exactly the same ; instruction sequence (the one above), so I doubt you can find something ; faster on Arm2. I must admit that before we went to sleep Fred was knowing ; the solution, but I asked him not to tell it to me, so that I proved myself ; I' m able to be as good as Fred. (I was a bit ashamed when Fred talked ; about using generated code, cos I' m supposed to be the expert in this!) ; Anyway, again lots of thanks to Fred for his help. ; ; >-------------------------------------------------------------------------< ; Parameters of the generated routines... ; r0=videoram adress of the start of the filament. ; r14=return adress. ; r1 will be modified! ; ; >-------------------------------------------------------------------------< ; Parameters of generating routine... ; r0=adress of a buffer, which will contain the table of all ; the routines adresses, and after this table, the code of ; the generated routines. ; The routines between 0 and (rss_rout_nb-1) assumes x pos is even, and ; routines between rss_rout_n and (2*rss_rout_nb-1) assumes x pos is odd. .rss_generate_code stmfd r13!,{r0-r12,r14} ; Clean... str r13,rss_old_stack add r1,r0,#rss_routs_nb*8 ; r1 points where to generate code. adr r2,rss_directions ldmdb r2,{r3,r4} ; r3 and r4 are random germs. adr r5,_opcodes ; r5 points on opcodes used. mov r6,#rss_routs_nb*2 ; Counts the nb of generated routs. ._gen_one_rout str r1,[r0],#4 ; Save adress of the routine. mov r7,#rss_nb_rnd ; r7=nb of rnd points per filament. mov r8,#0 ; r8=x pos of first pixie, cmp r6,#rss_routs_nb ; =0 for the first routs. movLE r8,#1 ; =1 for the last ones. mov r9,#0 ; r9=y offset. ._gen_one_pixie add r10,r9,r8,asr #1 ; r10=offset. tst r8,#1 ; Pixel in upperbits or lowerbits? bEQ _gen_up ; The pixel is in the 4 lowerbits. Generate code for it. ldmia r5,{r11-r13} ; Load opcodes. cmp r10,#0 ; Offset negative? bicMI r11,r11,#1<<23 ; Yes, then notify it in ldrB & strB. bicMI r13,r13,#1<<23 rsbMI r10,r10,#0 ; r10=abs(offset). add r11,r11,r10 ; r11='ldrB r6,[r6,#offset]'. add r13,r13,r10 ; r14='strPLB r6,[r7,#offset]'. stmia r1!,{r11-r13} ; Generate code. and r10,r3,#%111 ; r10=rnd(8). add r10,r2,r10,lsl #3 ; r10 points on the good direction. ldmia r10!,{r10,r11} ; r10=dx | r11=dy. add r8,r8,r10 ; x_pos+=dx. add r9,r9,r11 ; y_offset+=dy. add r3,r4,r3,ror #3 ; Next random number. mov r3,r3,ror r4 eor r4,r3,r4,ror #7 subS r7,r7,#1 ; One pixie generated bNE _gen_one_pixie ldr r10,[r5,#12] ; r10='mov pc,r14'. str r10,[r1],#4 ; Generate it. subS r6,r6,#1 ; One filament routine generated. bNE _gen_one_rout ldr r13,rss_old_stack ; Finished... ldmfd r13!,{r0-r12,pc} ; The pixel is in the 4 upperbits. Generate code for it. ._gen_up ldmdb r5,{r11-r14} ; Load opcodes. cmp r10,#0 ; Offset negative? bicMI r11,r11,#1<<23 ; Yes, then notify it in ldrB & strB. bicMI r14,r14,#1<<23 rsbMI r10,r10,#0 ; r10=abs(offset). add r11,r11,r10 ; r11='ldrB r6,[r7,#offset]'. add r14,r14,r10 ; r14='strNEB r6,[r7,#offset]'. stmia r1!,{r11-r14} ; Generate code. and r10,r3,#%111 ; r10=rnd(8). add r10,r2,r10,lsl #3 ; r10 points on the good direction. ldmia r10!,{r10,r11} ; r10=dx | r11=dy. add r8,r8,r10 ; x_pos+=dx. add r9,r9,r11 ; y_offset+=dy. add r3,r4,r3,ror #3 ; Next random number. mov r3,r3,ror r4 eor r4,r3,r4,ror #7 subS r7,r7,#1 ; One pixie generated bNE _gen_one_pixie ldr r10,[r5,#12] ; r10='mov pc,r14'. str r10,[r1],#4 ; Generate it. subS r6,r6,#1 ; One filament routine generated. bNE _gen_one_rout ldr r13,rss_old_stack ; Finished.... ldmfd r13!,{r0-r12,pc} ; The opcodes used by the generated code. ldrB r6,[r7,#0] ; Routine when x is even. tst r6,#&f subNE r6,r6,#1 strNEB r6,[r7,#0] ._opcodes ldrB r6,[r7,#0] ; Routine when x is odd. subS r6,r6,#1<<4 strPLB r6,[r7,#0] mov pc,r14 ; Well, mysterious instruction, huh? .random_germs dcd &eb1a2c37,&3fd2a145 .rss_directions dcd 0,160,0,-160,1,0,-1,0 dcd 1,160,-1,160,1,-160,-1,-160 .rss_old_stack ; Well... dcd 0 ;**************************************************************************** ;***** ***** ;***** Randomly Shaded Spline ***** ;***** ***** ;**************************************************************************** ; ; This routine draws a randomly shaded spline. We calculate a fixed amount ; of points in the spline, and save them in a table. Then, for each of this ; point, we randomly choose a filament, and jump at the corresponding rout. ; The clipping is performed individually for each filament. If the box ; around the point (and 'radius' of the box being maximum length of filament) ; is out of the screen or even partially clipped, we quite simply don' t draw ; the filament. ; The full incremental spline calculation trick was found in a spline rout ; by Jan/BASS, and then rewritten by me. (I don' t have exactly the same ; spline formulas as Jan does) As usual, Jan' s code is a very good source ; of inspiration. :) ; The x clipping was 'removed' because it was unusefull in this demo. ; ; >-------------------------------------------------------------------------< ; Parameters are... ; r0=adress of workscreen. ; r1=adress of the table of routines adresses. ; r2=adress of spline control brows. (x0,y0,x1,y1,x2,y2,x3,y3)*64 ; r10=adress of a 129*2 longs buffer. .random_shade_spline stmfd r13!,{r0-r12,r14} ; Be clean or crash! ldmia r2,{r2-r9} ; Load spline control brows. mov r2,r2,asr #6 ; Take integer part of their x coord. mov r4,r4,asr #6 mov r6,r6,asr #6 mov r8,r8,asr #6 ; cmp r2,#320 ; If all the control brows are on right ; cmpGE r4,#320 ; of the screen, then the whole spline ; cmpGE r6,#320 ; is on right of the screen ->quit. ; cmpGE r8,#320 ; ldmGEfd r13!,{r0-r12,pc} ; cmp r2,#0 ; Same comment when all brows on left. ; cmpLT r4,#0 ; cmpLT r6,#0 ; cmpLT r8,#0 ; ldmLTfd r13!,{r0-r12,pc} mov r3,r3,asr #6 ; Take integer part of y coords. mov r5,r5,asr #6 mov r7,r7,asr #6 mov r9,r9,asr #6 cmp r3,#256 ; All brows below?.. cmpGE r5,#256 cmpGE r7,#256 cmpGE r9,#256 ldmGEfd r13!,{r0-r12,pc} cmp r3,#0 ; Or above the screen. cmpLT r5,#0 cmpLT r7,#0 cmpLT r9,#0 ldmLTfd r13!,{r0-r12,pc} ; Now, using the coords of the control brows, we calculate the x and y ; compounds of the cubic spline coefficients, which are... ; a0=p0 ; a1=4*p1-4*p0 ; a2=-p3+4*p2-8*p1+5*p0 ; a3=2*p3-4*p2+4*p1-2*p0 mov r4,r4,lsl #2 ; r4=4x1. sub r11,r4,r2,lsl #1 add r11,r11,r8,lsl #1 sub r11,r11,r6,lsl #2 ; r11=a3x=2x3-4x2+4x1-2x0. rsb r6,r8,r6,lsl #2 add r6,r6,r2,lsl #2 add r6,r6,r2 sub r6,r6,r4,lsl #1 ; r6=a2x=-x3+4x2-8x1+5x0. sub r4,r4,r2,lsl #2 ; r4=a1x=4x1-4x0. mov r5,r5,lsl #2 ; r5=4y1. sub r12,r5,r3,lsl #1 add r12,r12,r9,lsl #1 sub r12,r12,r7,lsl #2 ; r12=a3y=2y3-4y2+4y1-2y0. rsb r7,r9,r7,lsl #2 add r7,r7,r3,lsl #2 add r7,r7,r3 sub r7,r7,r5,lsl #1 ; r7=a2y=-y3+4y2-8y1+5y0. sub r5,r5,r3,lsl #2 ; r5=a1y=4y1-4y0. ; So, here we have the following... ; r2 = a0x | r3 = a0y ; r4 = a1x | r5 = a1y ; r6 = a2x | r7 = a2y ; r11 = a3x | r12 = a3y ; Now, in order to work in a totally incremental way, we calculate ; inc1=a1*h+a2*h^2+a3*h^3 ; inc2=2*a2*h^2+6*a3*h^3 ; inc3=6*a3*h^3 ; Please note that we must convert all values in fixed point. mov r2,r2,lsl #rss_shift*3 ; r2=a0x. add r4,r6,r4,lsl #rss_shift add r4,r11,r4,lsl #rss_shift ; r4=inc1x=a1x*h+a2x*h^2+a3x*h^3. add r8,r11,r11,lsl #1 mov r8,r8,lsl #1 ; r8=inc3x=6*a3x*h^3. add r6,r8,r6,lsl #rss_shift+1 ; r6=inc2x=2*a2x*h^2+6*a3x*h^3. mov r3,r3,lsl #rss_shift*3 ; r3=a0y. add r5,r7,r5,lsl #rss_shift add r5,r12,r5,lsl #rss_shift ; r5=inc1y=a1y*h+a2y*h^2+a3y*h^3. add r9,r12,r12,lsl #1 mov r9,r9,lsl #1 ; r9=inc3y=6*a3y*h^3. add r7,r9,r7,lsl #rss_shift+1 ; r7=inc2y=2*a2y*h^2+6*a3y*h^3. ; It' s time to calculate the points of the spline and save them in the ; buffer pointed by r1. Note that in order to increase the number of points ; in a convenient way, half of them are calculated using a stupid linear ; interpolation. Less accurate, but a bit faster. #rept 64 add r11,r2,r4,asr #1 ; [r10|r11]=M+0.5*inc1. add r12,r3,r5,asr #1 stmia r10!,{r2,r3,r11,r12} ; Save M and M+0.5*inc1. add r2,r2,r4 ; M=M+inc1. add r3,r3,r5 add r4,r4,r6 ; inc1=inc1+inc2. add r5,r5,r7 add r6,r6,r8 ; inc2=inc2+inc3. add r7,r7,r9 #endr stmia r10!,{r2,r3} ; Save the last point. ; Time to draw the filaments of the spline. ; Here we have the following... ; r0=adress of workscreen. ; r1=adress of the table of routines adresses. ; r10 points after the points coords. sub r2,r10,#rss_nb_pts*8 ; r2 points on the coords buffer. adr r3,random_germs ldmia r3,{r3,r4} ; r3 & r4 are random numbers. mov r5,#rss_nb_pts ; Nb of filaments to draw. adr r14,rss_one_set ; Return adress. .rss_one_set add r3,r4,r3,ror #3 ; Next random number generation. mov r3,r3,ror r4 eor r4,r3,r4,ror #7 subS r5,r5,#1 ; One filament processed. bMI rss_the_end ldmia r2!,{r6,r7} ; r6=x<<rss_shift*3 | r7=y<<rss_shift*3. mov r6,r6,asr #rss_shift*3 ; r6=int(x). ; cmp r6,#rss_nb_rnd ; Set of pixels clipped or out? ; bMI rss_one_set ; cmp r6,#320-rss_nb_rnd ; bGE rss_one_set mov r7,r7,asr #rss_shift*3 ; r7=int(y). cmp r7,#rss_nb_rnd ; Set of pixels clipped or out? bMI rss_one_set cmp r7,#256-rss_nb_rnd bGE rss_one_set add r7,r7,r7,lsl #2 ; Make r6 point on good byte. add r7,r0,r7,lsl #5 add r7,r7,r6,asr #1 tst r6,#1 ; Flags=int(x) and 1. and r6,r3,#rss_routs_nb-1 ; r6=rnd(rss_routs_nb-1). addNE r6,r6,#rss_routs_nb ldr pc,[r1,r6,lsl #2] ; Execute the chosen routine. .rss_the_end adr r2,random_germs stmia r2,{r3,r4} ; Save the modified random germs. ldmfd r13!,{r0-r12,pc} ; The end.