1 files changed, 98 insertions, 0 deletions
diff --git a/src/screen.c b/src/screen.c
new file mode 100644
index 0000000..6f682ae
--- /dev/null
+++ b/src/screen.c
@@ -0,0 +1,98 @@
+#include <lib.h>
+#include <screen.h>
+#include <bochs.h>
+#include <stddef.h>
+#include <stdint.h>
+
+#define SCREEN_WIDTH	       1024
+#define SCREEN_HEIGHT          768
+#define SCREEN_BIT_DEPTH       32
+
+struct rgb {
+	uint8_t r;
+	uint8_t g;
+	uint8_t b;
+};
+
+struct hsv {
+	uint16_t h;
+	uint16_t s;
+	uint16_t v;
+};
+
+static uint32_t *buffer = NULL;
+static uint32_t width, height;
+static uint8_t bit_depth;
+
+static uint16_t angle;
+
+static void set_pixel(struct rgb color, uint16_t x, uint16_t y) {
+	uint32_t offset = y * width + x;
+	buffer[offset] = (color.b << 0) | (color.g << 8) | (color.r << 16);
+}
+
+static float fmod(float f, float m) {
+	return f - (int)(f / m) * m;
+}
+
+static float fabs(float f) {
+	return f > 0 ? f : -f;
+}
+
+static struct rgb htor(struct hsv hsv) {
+	struct rgb rgb;
+	float s = hsv.s / 100.0;
+	float v = hsv.v / 100.0;
+	float c = s * v;
+	float x = c * (1-fabs(fmod(hsv.h/60.0, 2) - 1));
+	float m = v - c;
+	float r,g,b;
+
+	if (hsv.h < 60) {
+		r = c; g = x; b = 0;
+	} else if (hsv.h >= 60 && hsv.h < 120) {
+		r = x; g = c; b = 0;
+	} else if (hsv.h >= 120 && hsv.h < 180) {
+		r = 0; g = c; b = x;
+	} else if (hsv.h >= 180 && hsv.h < 240) {
+		r = 0; g = x; b = c;
+	} else if (hsv.h >= 240 && hsv.h < 300) {
+		r = x; g = 0; b = c;
+	} else {
+		r = c; g = 0; b = x;
+	}
+
+	rgb.r = (r + m) * 255;
+	rgb.g = (g + m) * 255;
+	rgb.b = (b + m) * 255;
+
+	return rgb;
+}
+
+static struct rgb get_color(uint16_t a, uint16_t x, uint16_t y) {
+	struct hsv hsv = {
+		.h = a,
+		.s = x * 100.0 / width,
+		.v = y * 100.0 / height,
+	};
+	return htor(hsv);
+}
+
+void screen_init(void) {
+	angle = 0;
+	width = SCREEN_WIDTH;
+	height = SCREEN_HEIGHT;
+	bit_depth = SCREEN_BIT_DEPTH;
+	buffer = bochs_init(width, height, bit_depth);
+}
+
+void screen_redraw(void) {
+	for (uint16_t y = 0; y < height; y++) {
+		for (uint16_t x = 0; x < width; x++) {
+			struct rgb color = get_color(angle, x, height - y);
+			set_pixel(color, x, y);
+		}
+	}
+	angle++;
+	angle %= 360;
+}