introduced graphics module wrapper for cx16 to make even more programs compatible

compiler/res/prog8lib/c64/graphics.p8

@@ -2,7 +2,7 @@
 %import textio
 
 ; bitmap pixel graphics module for the C64
-; only black/white monchrome for now
+; only black/white monchrome 320x200 for now
 ; assumes bitmap screen memory is $2000-$3fff
 
 graphics {
@@ -135,33 +135,33 @@ graphics {
         }
     }
 
-    sub disc(uword cx, ubyte cy, ubyte radius) {
+    sub disc(uword xcenter, ubyte ycenter, ubyte radius) {
         ; Midpoint algorithm, filled
         ubyte xx = radius
         ubyte yy = 0
         byte decisionOver2 = 1-xx as byte
 
         while xx>=yy {
-            ubyte cy_plus_yy = cy + yy
-            ubyte cy_min_yy = cy - yy
-            ubyte cy_plus_xx = cy + xx
-            ubyte cy_min_xx = cy - xx
+            ubyte ycenter_plus_yy = ycenter + yy
+            ubyte ycenter_min_yy = ycenter - yy
+            ubyte ycenter_plus_xx = ycenter + xx
+            ubyte ycenter_min_xx = ycenter - xx
 
-            for internal_plotx in cx to cx+xx {
-                internal_plot(cy_plus_yy)
-                internal_plot(cy_min_yy)
+            for internal_plotx in xcenter to xcenter+xx {
+                internal_plot(ycenter_plus_yy)
+                internal_plot(ycenter_min_yy)
             }
-            for internal_plotx in cx-xx to cx-1 {
-                internal_plot(cy_plus_yy)
-                internal_plot(cy_min_yy)
+            for internal_plotx in xcenter-xx to xcenter-1 {
+                internal_plot(ycenter_plus_yy)
+                internal_plot(ycenter_min_yy)
             }
-            for internal_plotx in cx to cx+yy {
-                internal_plot(cy_plus_xx)
-                internal_plot(cy_min_xx)
+            for internal_plotx in xcenter to xcenter+yy {
+                internal_plot(ycenter_plus_xx)
+                internal_plot(ycenter_min_xx)
             }
-            for internal_plotx in cx-yy to cx {
-                internal_plot(cy_plus_xx)
-                internal_plot(cy_min_xx)
+            for internal_plotx in xcenter-yy to xcenter {
+                internal_plot(ycenter_plus_xx)
+                internal_plot(ycenter_min_xx)
             }
             yy++
             if decisionOver2<=0

compiler/res/prog8lib/cx16/graphics.p8

@@ -0,0 +1,56 @@
+%target cx16
+%import syslib
+
+; bitmap pixel graphics module for the CommanderX16
+; wraps the graphics functions that are in ROM.
+; only black/white monchrome 320x200 for now.
+
+graphics {
+
+    sub enable_bitmap_mode() {
+        ; enable bitmap screen, erase it and set colors to black/white.
+        void cx16.screen_set_mode($80)
+        cx16.r0 = 0
+        cx16.GRAPH_init()
+        clear_screen(1, 0)
+    }
+
+    sub clear_screen(ubyte pixelcolor, ubyte bgcolor) {
+        cx16.GRAPH_set_colors(pixelcolor, pixelcolor, bgcolor)
+        cx16.GRAPH_clear()
+    }
+
+    sub line(uword @zp x1, ubyte @zp y1, uword @zp x2, ubyte @zp y2) {
+        cx16.r0 = x1
+        cx16.r1 = y1
+        cx16.r2 = x2
+        cx16.r3 = y2
+        cx16.GRAPH_draw_line()
+    }
+
+    sub circle(uword xcenter, ubyte ycenter, ubyte radius) {
+        cx16.r0 = xcenter - radius/2
+        cx16.r1 = ycenter - radius/2
+        cx16.r2 = radius
+        cx16.r3 = radius
+        cx16.GRAPH_draw_oval(false)          ; TODO  currently seems to crash
+    }
+
+    sub disc(uword xcenter, ubyte ycenter, ubyte radius) {
+        cx16.r0 = xcenter - radius/2
+        cx16.r1 = ycenter - radius/2
+        cx16.r2 = radius
+        cx16.r3 = radius
+        cx16.GRAPH_draw_oval(true)          ; TODO  currently seems to crash
+    }
+
+    sub  plot(uword plotx, ubyte ploty) {
+        cx16.r0 = plotx
+        cx16.r1 = ploty
+        cx16.FB_cursor_position()
+        cx16.FB_cursor_position()
+        cx16.FB_set_pixel(1)
+    }
+}
+
+

examples/cube3d-gfx.p8

@@ -1,9 +1,7 @@
-%target c64
-%import graphics
 %import syslib
+%import graphics
 
-; TODO make the graphics library not C64 specific
-
+; Note: this program is compatible with C64 and CX16.
 
 main {
 
@@ -38,13 +36,23 @@ main {
             angley+=217
             anglez+=452
 
-            while c64.RASTER!=255 {
-            }
-            while c64.RASTER!=254 {
-            }
+            wait_a_little_bit()
         }
     }
 
+    sub wait_a_little_bit() {
+        %asm {{
+            stx  P8ZP_SCRATCH_REG
+            lda  #0
+            jsr  c64.SETTIM
+-           jsr  c64.RDTIM
+            cmp  #1
+            bne  -
+            ldx  P8ZP_SCRATCH_REG
+            rts
+        }}
+    }
+
     sub rotate_vertices(ubyte ax, ubyte ay, ubyte az) {
         ; rotate around origin (0,0,0)
 

examples/line-circle-gfx.p8

@@ -1,6 +1,6 @@
 %import graphics
 
-; TODO make graphics lib cross-system
+; Note: this program is compatible with C64 and CX16.
 
 main {
 

examples/mandelbrot-gfx.p8

@@ -3,10 +3,10 @@
 %zeropage floatsafe
 
 ; Draw a mandelbrot in graphics mode (the image will be 256 x 200 pixels).
-; NOTE: this will take an eternity to draw on a real c64.
+; NOTE: this will take an eternity to draw on a real c64. A CommanderX16 is a bit faster.
 ; even in Vice in warp mode (700% speed on my machine) it's slow, but you can see progress
 
-; TODO make graphics lib cross-system
+; Note: this program is compatible with C64 and CX16.
 
 main {
     const ubyte width = 255