Implement graphics subsystem with VGA mode 0x13 and drawing primitives (AI)

apps/libc/syscalls.h

@@ -31,6 +31,7 @@ typedef int int32_t;
 #define SYS_SEND    15
 #define SYS_RECV    16
 #define SYS_SOCKSTATE 17
+#define SYS_GFX       18
 
 static inline int32_t syscall0(int num) {
     int32_t ret;
@@ -194,6 +195,92 @@ static inline int32_t sockstate(int32_t sockfd) {
     return syscall1(SYS_SOCKSTATE, (uint32_t)sockfd);
 }
 
+/* ================================================================
+ * Graphics system calls
+ * ================================================================ */
+
+/** Graphics sub-commands. */
+#define GFX_CMD_ENTER     0
+#define GFX_CMD_LEAVE     1
+#define GFX_CMD_PIXEL     2
+#define GFX_CMD_CLEAR     3
+#define GFX_CMD_FILL_RECT 4
+#define GFX_CMD_LINE      5
+#define GFX_CMD_CIRCLE    6
+#define GFX_CMD_GET_INFO  7
+
+/** Graphics mode dimensions. */
+#define GFX_WIDTH  320
+#define GFX_HEIGHT 200
+
+/** Palette color constants. */
+#define GFX_BLACK         0
+#define GFX_BLUE          1
+#define GFX_GREEN         2
+#define GFX_CYAN          3
+#define GFX_RED           4
+#define GFX_MAGENTA       5
+#define GFX_BROWN         6
+#define GFX_LIGHT_GREY    7
+#define GFX_DARK_GREY     8
+#define GFX_LIGHT_BLUE    9
+#define GFX_LIGHT_GREEN   10
+#define GFX_LIGHT_CYAN    11
+#define GFX_LIGHT_RED     12
+#define GFX_LIGHT_MAGENTA 13
+#define GFX_YELLOW        14
+#define GFX_WHITE         15
+
+/** Command structs for complex drawing operations. */
+typedef struct { uint32_t x, y, w, h, color; } gfx_rect_t;
+typedef struct { uint32_t x1, y1, x2, y2, color; } gfx_line_t;
+typedef struct { uint32_t cx, cy, r, color; } gfx_circle_t;
+
+/** Convert RGB (0-255) to palette index using 6x6x6 color cube. */
+static inline uint32_t gfx_rgb(uint32_t r, uint32_t g, uint32_t b) {
+    return 16 + (r / 51) * 36 + (g / 51) * 6 + (b / 51);
+}
+
+/** Enter graphics mode (320x200x256). */
+static inline int32_t gfx_enter(void) {
+    return syscall1(SYS_GFX, GFX_CMD_ENTER);
+}
+
+/** Leave graphics mode, return to text. */
+static inline int32_t gfx_leave(void) {
+    return syscall1(SYS_GFX, GFX_CMD_LEAVE);
+}
+
+/** Set a pixel. */
+static inline int32_t gfx_pixel(uint32_t x, uint32_t y, uint32_t color) {
+    return syscall3(SYS_GFX, GFX_CMD_PIXEL, (x | (y << 16)), color);
+}
+
+/** Clear screen with a color. */
+static inline int32_t gfx_clear(uint32_t color) {
+    return syscall2(SYS_GFX, GFX_CMD_CLEAR, color);
+}
+
+/** Fill a rectangle. */
+static inline int32_t gfx_fill_rect(const gfx_rect_t *r) {
+    return syscall2(SYS_GFX, GFX_CMD_FILL_RECT, (uint32_t)r);
+}
+
+/** Draw a line. */
+static inline int32_t gfx_line(const gfx_line_t *l) {
+    return syscall2(SYS_GFX, GFX_CMD_LINE, (uint32_t)l);
+}
+
+/** Draw a filled circle. */
+static inline int32_t gfx_circle(const gfx_circle_t *c) {
+    return syscall2(SYS_GFX, GFX_CMD_CIRCLE, (uint32_t)c);
+}
+
+/** Get graphics info: returns (width | height<<16). */
+static inline int32_t gfx_get_info(void) {
+    return syscall1(SYS_GFX, GFX_CMD_GET_INFO);
+}
+
 /* Basic string operations for user-space */
 static inline uint32_t strlen(const char *s) {
     uint32_t len = 0;