Moved outcode calculation in a separate module.

git-svn-id: svn://svn.cc65.org/cc65/trunk@4462 b7a2c559-68d2-44c3-8de9-860c34a00d81

diff --git a/libsrc/tgi/Makefile b/libsrc/tgi/Makefile
index e594b39fc01cc79022f9223f5ce31d640ef85647..17f60a904a77861ce63167aad85a665edc4ffa34 100644 (file)
--- a/libsrc/tgi/Makefile
+++ b/libsrc/tgi/Makefile
@@ -67,6 +67,7 @@ S_OBJS =              tgi-kernel.o            \
                 tgi_linepop.o           \
                 tgi_lineto.o            \
                        tgi_map_mode.o          \
+                tgi_outcode.o           \
                 tgi_outtext.o           \
                 tgi_outtextxy.o         \
                 tgi_popxy.o             \

diff --git a/libsrc/tgi/tgi_clippedline.s b/libsrc/tgi/tgi_clippedline.s
index c4085c019b8e0e69f0ca3392453ee351abb2256a..b32b819ece941b41d5b4ee872ea0e1ade0aabf4e 100644 (file)
--- a/libsrc/tgi/tgi_clippedline.s
+++ b/libsrc/tgi/tgi_clippedline.s
@@ -18,15 +18,11 @@
 
 .bss
 
-; Line coordinates. Must be set before calling tgi_clippedline
-tgi_clip_x1:    .res    2
-tgi_clip_y1:    .res    2
-tgi_clip_x2:    .res    2
-tgi_clip_y2:    .res    2
-
+; Outcodes for both ends
 tgi_clip_o1:    .res    1
 tgi_clip_o2:    .res    1
 
+; Line deltas
 tgi_clip_d:     .res    1
 tgi_clip_dx:    .res    2
 tgi_clip_dy:    .res    2
@@ -34,91 +30,6 @@ tgi_clip_dy:    .res    2
 tgi_clip_sign:  .res    1
 
 
-;----------------------------------------------------------------------------
-; outcode constants.
-
-CLIP_NONE       = $00
-CLIP_LEFT       = $01
-CLIP_RIGHT      = $02
-CLIP_BOTTOM     = $04
-CLIP_TOP        = $08
-
-
-
-;----------------------------------------------------------------------------
-; Generate a Cohen Sutherland outcode
-;
-; void outcode ()
-; {
-;     unsigned char o = 0;
-;     if (Y < 0) {
-;         o = CLIP_BOTTOM;
-;     } else if (Y >= yres) {
-;         o = CLIP_TOP;
-;     }
-;     if (X < 0) {
-;         o |= CLIP_LEFT;
-;     } else if (X >= xres) {
-;         o |= CLIP_RIGHT;
-;     }
-;     return o;
-; }
-
-.code
-.proc   outcode
-
-        lda     #CLIP_NONE
-        sta     tmp1
-
-; Check Y coordinate
-
-        lda     tgi_clip_y1+1,y         ; High byte of Y1
-        bmi     L2                      ; Jump if bottom clip
-
-        ldx     tgi_clip_y1,y           ; Low byte of Y1
-        cpx     _tgi_yres
-        sbc     _tgi_yres+1
-        bvs     L1
-        eor     #$80
-L1:     bpl     L4
-        lda     #CLIP_TOP               ; Top clipping necessary
-        bne     L3
-L2:     lda     #CLIP_BOTTOM
-L3:     sta     tmp1                    ; Save temp outcode
-
-
-; Check X coordinate
-
-L4:     lda     tgi_clip_x1+1,y         ; High byte of X1
-        bmi     L7                      ; Jump if left clip
-
-        ldx     tgi_clip_x1,y           ; Low byte of X1
-        cpx     _tgi_xres
-        sbc     _tgi_xres+1
-        bvs     L5
-        eor     #$80
-L5:     bmi     L6
-
-; No right or left clipping necessary
-
-        lda     tmp1
-        rts
-
-; Need right clipping
-
-L6:     lda     #CLIP_RIGHT
-        ora     tmp1
-        rts
-
-; Need left clipping
-
-L7:     lda     #CLIP_LEFT
-        ora     tmp1
-        rts
-
-.endproc
-
-
 ;----------------------------------------------------------------------------
 ; Calculate outcodes for both ends of the line
 ;
@@ -127,7 +38,7 @@ L7:     lda     #CLIP_LEFT
 .proc   outcode1
 
         ldy     #0
-        jsr     outcode
+        jsr     tgi_outcode
         sta     tgi_clip_o1
         rts
 
@@ -136,8 +47,8 @@ L7:     lda     #CLIP_LEFT
 .code
 .proc   outcode2
 
-        ldy     #(tgi_clip_y2 - tgi_clip_y1)
-        jsr     outcode
+        ldy     #<(tgi_clip_y2 - tgi_clip_y1)
+        jsr     tgi_outcode
         sta     tgi_clip_o2
         rts
 
@@ -256,7 +167,7 @@ L7:     lda     #CLIP_LEFT
 
 ; Generate the absolute value of y/a and calculate the sign of the final
 ; result
-                      
+
         jsr     prepare_coord
 
 ; All values are positive now (dx/dy have been made positive in calcdeltas)
@@ -381,7 +292,7 @@ HaveDeltas:
 
 ; Need to clip X1/Y1
 
-        lsr     a                       ; Check for CLIP_LEFT
+        lsr     a                       ; Check for TGI_CLIP_LEFT
         bcc     L3
 
 ; tgi_clip_y1 += (0 - tgi_clip_x1) * tgi_clip_dy / tgi_clip_dx;
@@ -391,7 +302,7 @@ HaveDeltas:
         tax
         beq     L4
 
-L3:     lsr     a                       ; Check for CLIP_RIGHT
+L3:     lsr     a                       ; Check for TGI_CLIP_RIGHT
         bcc     L5
 
 ; tgi_clip_y1 += (tgi_xmax - tgi_clip_x1) * tgi_clip_dy / tgi_clip_dx;
@@ -423,7 +334,7 @@ L4:     tay
         lda     tgi_clip_o1
         lsr     a
         lsr     a
-L5:     lsr     a                               ; Check for CLIP_BOTTOM
+L5:     lsr     a                               ; Check for TGI_CLIP_BOTTOM
         bcc     L6
 
 ; tgi_clip_x1 = (0 - tgi_clip_y1) * tgi_clip_dx / tgi_clip_dy;
@@ -433,7 +344,7 @@ L5:     lsr     a                               ; Check for CLIP_BOTTOM
         tax
         beq     L7
 
-L6:     lsr     a                               ; Check for CLIP_TOP
+L6:     lsr     a                               ; Check for TGI_CLIP_TOP
         bcc     L8
 
 ; tgi_clip_x1 += (tgi_ymax - tgi_clip_y1) * tgi_clip_dx / tgi_clip_dy;
@@ -471,7 +382,7 @@ L10:    lda     tgi_clip_o2
 
 ; Need to clip X2/Y2
 
-        lsr     a                       ; Check for CLIP_LEFT
+        lsr     a                       ; Check for TGI_CLIP_LEFT
         bcc     L11
 
 ; tgi_clip_y2 += (0 - tgi_clip_x2) * tgi_clip_dy / tgi_clip_dx;
@@ -481,7 +392,7 @@ L10:    lda     tgi_clip_o2
         tax
         beq     L12
 
-L11:    lsr     a                       ; Check for CLIP_RIGHT
+L11:    lsr     a                       ; Check for TGI_CLIP_RIGHT
         bcc     L13
 
 ; tgi_clip_y2 += (tgi_xmax - tgi_clip_x2) * tgi_clip_dy / tgi_clip_dx;
@@ -513,7 +424,7 @@ L12:    tay
         lda     tgi_clip_o2
         lsr     a
         lsr     a
-L13:    lsr     a                       ; Check for CLIP_BOTTOM
+L13:    lsr     a                       ; Check for TGI_CLIP_BOTTOM
         bcc     L14
 
 ; tgi_clip_x2 += (0 - tgi_clip_y2) * tgi_clip_dx / tgi_clip_dy;
@@ -523,7 +434,7 @@ L13:    lsr     a                       ; Check for CLIP_BOTTOM
         tax
         beq     L15
 
-L14:    lsr     a                               ; Check for CLIP_TOP
+L14:    lsr     a                       ; Check for TGI_CLIP_TOP
         bcc     L16
 
 ; tgi_clip_x2 += (tgi_ymax - tgi_clip_y2) * tgi_clip_dx / tgi_clip_dy;

diff --git a/libsrc/tgi/tgi_outcode.s b/libsrc/tgi/tgi_outcode.s
new file mode 100644 (file)
index 0000000..243e5c2
--- /dev/null
+++ b/libsrc/tgi/tgi_outcode.s
@@ -0,0 +1,98 @@
+;
+; Ullrich von Bassewitz, 2009-10-25
+;
+; Generates clipping outcodes for Cohen Sutherland and others.
+;
+
+        .include "tgi-kernel.inc"
+        .include "zeropage.inc"
+
+;----------------------------------------------------------------------------
+; Data
+
+.bss
+
+; Clipping coordinates.
+tgi_clip_x1:    .res    2
+tgi_clip_y1:    .res    2
+tgi_clip_x2:    .res    2
+tgi_clip_y2:    .res    2
+
+;----------------------------------------------------------------------------
+; Generate a Cohen Sutherland outcode
+;
+; void outcode ()
+; {
+;     unsigned char o = 0;
+;     if (Y < 0) {
+;         o = TGI_CLIP_BOTTOM;
+;     } else if (Y >= yres) {
+;         o = TGI_CLIP_TOP;
+;     }
+;     if (X < 0) {
+;         o |= TGI_CLIP_LEFT;
+;     } else if (X >= xres) {
+;         o |= TGI_CLIP_RIGHT;
+;     }
+;     return o;
+; }
+;
+; The function return the outcode in A and the flags for the outcode are
+; correctly set.
+;
+
+.code
+.proc   tgi_outcode           
+
+        lda     #TGI_CLIP_NONE
+        sta     tmp1
+
+; Check Y coordinate
+
+        lda     tgi_clip_y1+1,y         ; High byte of Y1
+        bmi     L2                      ; Jump if bottom clip
+
+        ldx     tgi_clip_y1,y           ; Low byte of Y1
+        cpx     _tgi_yres
+        sbc     _tgi_yres+1
+        bvs     L1
+        eor     #$80
+L1:     bpl     L4
+        lda     #TGI_CLIP_TOP               ; Top clipping necessary
+        bne     L3
+L2:     lda     #TGI_CLIP_BOTTOM
+L3:     sta     tmp1                    ; Save temp outcode
+
+
+; Check X coordinate
+
+L4:     lda     tgi_clip_x1+1,y         ; High byte of X1
+        bmi     L7                      ; Jump if left clip
+
+        ldx     tgi_clip_x1,y           ; Low byte of X1
+        cpx     _tgi_xres
+        sbc     _tgi_xres+1
+        bvs     L5
+        eor     #$80
+L5:     bmi     L6
+
+; No right or left clipping necessary
+
+        lda     tmp1
+        rts
+
+; Need right clipping
+
+L6:     lda     #TGI_CLIP_RIGHT
+        ora     tmp1
+        rts
+
+; Need left clipping
+
+L7:     lda     #TGI_CLIP_LEFT
+        ora     tmp1
+        rts
+
+.endproc
+
+