Some graphics tweaks

.vscode/settings.json

@@ -12,9 +12,6 @@
 
     "C_Cpp.default.includePath": ["src/kernel/include", "sysroot/usr/include"],
     "C_Cpp.default.cStandard": "c17",
-    "files.associations": {
-        "cpu.h": "c"
-    },
     "[c]": {
         "editor.tabSize": 2,
     },

src/kernel/boot/TEMP-test_scheduler.c

@@ -3,6 +3,7 @@
 #include <mittos/graphics.h>
 #include <memory.h>
 #include <cpu.h>
+#include <math.h>
 
 extern gfx_context *term_fb;
 extern gfx_context kernel_fb;
@@ -11,8 +12,10 @@ int *position = (void *)0x20000;
 
 void thread1() {
   int a = 1;
+  double prev = 0;
   gfx_context *ctx =
       framebuffer_make_subcontext(&kernel_fb, 700, 300, 100, 100);
+  __asm__("sti");
   while(1) {
     putCharacter(term_fb,
         *position, *position,
@@ -20,14 +23,19 @@ void thread1() {
         '0'+(a++%10)
     );
     int s = (current_cpu->timer_ticks/1000)%10;
+    double cur = (double)(current_cpu->timer_ticks/100);
     putCharacter(term_fb,
         0, 0,
         RGB(255,255,0), RGB(0,0,0),
         '0'+(s%10)
     );
     flip(term_fb);
-    draw_line(ctx, 0, 100, 50, ((a-1)%100), RGB(0,0,0));
-    draw_line(ctx, 0, 100, 50, (a%100), RGB(255,0,0));
+
+    double angle = cur/3.14*2;
+
+    draw_line(ctx, 50, 50 + (int)(50*cos(prev)), 50, 50 + (int)(50*sin(prev)), RGB(0,0,0));
+    draw_line(ctx, 50, 50 + (int)(50*cos(angle)), 50, 50 + (int)(50*sin(angle)), RGB(255,0,0));
+    prev = angle;
     flip(ctx);
     sched_yield();
   }
@@ -35,7 +43,17 @@ void thread1() {
 
 void thread2() {
   int a = 0;
+  gfx_context *ctx =
+      framebuffer_make_subcontext(&kernel_fb, 800, 400, 100, 100);
+  __asm__("sti");
   while(1) {
+    double pos = (double)(current_cpu->timer_ticks/100);
+    fill_rect(ctx, 0, 0, 100, 100, 0);
+    for(int i = 0; i < 10000; i++) {
+      putpixel(ctx, i/100, 50 + (int)(50.0*sin(pos + ((double)i)/1000.0)), RGB(0,0,255));
+      putpixel(ctx, i/100, 50 + (int)(50.0*cos(pos + ((double)i)/1000.0)), RGB(255,0,0));
+    }
+    flip(ctx);
     putCharacter(term_fb,
         *position, *position,
         RGB(0,255,255), RGB(0,0,0),

src/kernel/boot/kmain.c

@@ -41,8 +41,6 @@ void kmain(uint64_t multiboot_magic, void *multiboot_data) {
 
   cpu_init();
 
-  __asm__("sti");
-
   debug_info("Boot complete\n");
 
 
@@ -50,6 +48,7 @@ void kmain(uint64_t multiboot_magic, void *multiboot_data) {
   irq_unmask(IRQ_PS2_KBD);
   TEMP_test_scheduler();
 
+  __asm__("sti");
 
   start_scheduler();
 

src/kernel/cpu/timer.c

@@ -69,6 +69,7 @@ volatile int ctr = 0;
 registers *apic_timer_handler(registers *r) {
   current_cpu->timer_ticks++;
   irq_ack();
+  // k_sched_yield();
   return r;
 }
 

src/libmittos/graphics/graphics.c

@@ -27,25 +27,32 @@ void draw_line(
     uint64_t y0, uint64_t y1,
     uint32_t clr
 ) {
+  // https://en.wikipedia.org/wiki/Bresenham%27s_line_algorithm
+
   int64_t dx = x1 > x0 ? x1 - x0 : x0 - x1;
+  int sx = x0 < x1 ? 1 : -1;
   int64_t dy = y1 > y0 ? y1 - y0 : y0 - y1;
-  int sx = x1 > x0 ? 1 : -1;
-  int sy = y1 > y0 ? 1 : -1;
-  uint64_t x = x0, y = y0;
-  int64_t diff = dx - dy;
+  dy = -dy;
+  int sy = y0 < y1 ? 1 : -1;
+  int64_t err = dx + dy;
+
   uint32_t *fb = (uint32_t *)ctx->buffer;
   while(1) {
-    if(0 < x && x < ctx->width &&
-        0 < y && y < ctx->height)
-      fb[PXL(ctx, x, y)] = clr;
-    if(x == x1 && y == y1) break;
+    if(0 < x0 && x0 < ctx->width &&
+        0 < y0 && y0 < ctx->height)
+      fb[PXL(ctx, x0, y0)] = clr;
+    if(x0 == x1 && y0 == y1) break;
 
-    if((2*diff) > -dy) {
-      diff -= dy;
-      x += sx;
-    } else {
-      diff += dx;
-      y += sy;
+    int64_t e2 = 2*err;
+    if(e2 >= dy) {
+      if(x0 == x1) break;
+      err += dy;
+      x0 += sx;
+    }
+    if(e2 <= dx) {
+      if(y0 == y1) break;
+      err += dx;
+      y0 += sy;
     }
   }
 }