Kandinsky now uses KDSetPixel for framebuffer access

kandinsky/src/line.c

@@ -1,8 +1,8 @@
 #include <kandinsky/line.h>
-#include <kandinsky/referential.h>
+#include <kandinsky/pixel.h>
 
-void KDDrawLine(KDPoint p1, KDPoint p2) {
+void KDDrawLine(KDPoint p1, KDPoint p2) { //, KDColor c) {
   for (KDCoordinate x = p1.x; x<p2.x; x++) {
-//    COLOR(KDPOINT(x, p1.y)) = 0xFF;
+    KDSetPixel(KDPOINT(x, p1.y), 0xFF /* c */);
   }
 }

kandinsky/src/pixel.c

@@ -0,0 +1,42 @@
+#include <kandinsky/pixel.h>
+#include <kandinsky/config.h>
+#include <assert.h>
+
+static KDPoint sOrigin = {.x = 0, .y = 0};
+
+#define BIT_MASK(high, low) ((((uint32_t)1<<((high)-(low)+1))-1)<<(low))
+#define BIT_VALUE(value, high, low) (((value)<<(low))&BIT_MASK(high, low))
+
+static inline void set_color(KDColor * address, int8_t high_bit, int8_t low_bit, KDColor value) {
+  assert(high_bit-low_bit+1 <= 8*sizeof(KDColor)); // Interval too large
+  assert(low_bit >= 0); //  Interval starts too early
+  assert(low_bit < 8*sizeof(KDColor)); // Interval ends too late
+  KDColor mask = ((((KDColor)1<<(high_bit-low_bit+1))-1)<<low_bit);
+  assert(address >= KD_FRAMEBUFFER_ADDRESS);
+  assert(address < (KD_FRAMEBUFFER_ADDRESS+(KD_FRAMEBUFFER_WIDTH*KD_FRAMEBUFFER_HEIGHT*KD_BITS_PER_PIXEL)/8));
+  *address = (*address & ~mask) | (value & mask);
+}
+
+void KDSetOrigin(KDPoint origin) {
+  sOrigin = origin;
+}
+
+KDPoint KDGetOrigin() {
+  return sOrigin;
+}
+
+void KDSetPixel(KDPoint p, KDColor c) {
+  assert(p.x >= 0);
+  assert(p.x < KD_FRAMEBUFFER_WIDTH);
+  assert(p.y >= 0);
+  assert(p.y < KD_FRAMEBUFFER_HEIGHT);
+  int pixels_offset = p.y*(KD_FRAMEBUFFER_WIDTH) + p.x;
+  int bits_offset = (KD_BITS_PER_PIXEL)*pixels_offset;
+  const uint8_t color_bitsize = 8*sizeof(KDColor);
+  // Notice: the "const" here is rather important. Indeed, it hints the compiler
+  // for the following "modulo", which helps us avoid idivmod.
+  int color_offset = bits_offset/color_bitsize;
+  int8_t low_bit = bits_offset % color_bitsize;
+  int8_t high_bit = low_bit + KD_BITS_PER_PIXEL - 1;
+  set_color((KDColor *)(KD_FRAMEBUFFER_ADDRESS+color_offset), high_bit, low_bit, c);
+}

kandinsky/src/rect.c

@@ -1,9 +1,15 @@
 #include <kandinsky/rect.h>
-#include <kandinsky/referential.h>
+#include <kandinsky/pixel.h>
 #include <string.h>
 
 void KDFillRect(KDRect rect, KDColor color) {
-  for (KDCoordinate y = rect.y ; y < (rect.y + rect.height); y++) {
-    memset(KDPixelAddress((KDPoint){.x=rect.x, .y=y}), color, rect.width);
+  //for (KDCoordinate y = rect.y ; y < (rect.y + rect.height); y++) {
+    //memset(KDPixelAddress((KDPoint){.x=rect.x, .y=y}), color, rect.width);
+  //}
+  KDPoint p;
+  for (p.x = rect.x; p.x<(rect.x+rect.width-1); p.x++) {
+    for (p.y = rect.y; p.y<(rect.y+rect.height-1); p.y++) {
+      KDSetPixel(p, color);
+    }
   }
 }

kandinsky/src/referential.c

@@ -1,20 +0,0 @@
-#include <kandinsky/referential.h>
-#include <kandinsky/config.h>
-
-static KDPoint sOrigin = {.x = 0, .y = 0};
-
-void KDSetOrigin(KDPoint origin) {
-  sOrigin = origin;
-}
-
-KDPoint KDGetOrigin() {
-  return sOrigin;
-}
-
-KDColor * KDPixelAddress(KDPoint p) {
-  KDPoint origin = KDGetOrigin();
-  return (KDColor *)(KD_FRAMEBUFFER_ADDRESS
-      + KD_FRAMEBUFFER_WIDTH*(p.y + origin.y)
-      + (p.x + origin.x));
-}
-

kandinsky/src/text.c

@@ -1,12 +1,12 @@
 #include <kandinsky/text.h>
-#include <kandinsky/referential.h>
+#include <kandinsky/pixel.h>
 #include <string.h>
 #include "font.h"
 
 void KDDrawChar(char character, KDPoint p) {
   for (int j=0; j<BITMAP_FONT_CHARACTER_HEIGHT;j++) {
     for (int i=0; i<BITMAP_FONT_CHARACTER_WIDTH;i++) {
-      COLOR(KDPOINT(p.x+i, p.y+j)) = 0xFF-bitmapFont[character-BITMAP_FONT_FIRST_CHARACTER][j][i];
+      KDSetPixel(KDPOINT(p.x+i, p.y+j), 0xFF-bitmapFont[character-BITMAP_FONT_FIRST_CHARACTER][j][i]);
     }
   }
 }