Add levelling

renderer.c

@@ -20,6 +20,8 @@ static int front, back;
 static uint32_t width, height;
 static mat3_t view;
 
+static bool wrap;
+
 static vec3_t vert_buf[MAX_VERTS];
 
 static void page_flip_handler(int, unsigned, unsigned, unsigned, void *)
@@ -34,6 +36,13 @@ static void set_pixel(uint32_t x, uint32_t y)
 
 static void draw_line(vec3_t v1, vec3_t v2)
 {
+	v1.x /= v1.z;
+	v1.y /= v1.z;
+	v1.z = 1;
+	v2.x /= v2.z;
+	v2.y /= v2.z;
+	v2.z = 1;
+
 	const float delta_x = v2.x - v1.x;
 	const float delta_y = v2.y - v1.y;
 	const float step = fmaxf(fabsf(delta_x), fabsf(delta_y));
@@ -43,16 +52,20 @@ static void draw_line(vec3_t v1, vec3_t v2)
 
 		for (unsigned i = 0; i <= step; ++i) {
 			float x = roundf(v1.x + i * step_x);
-			if (x >= width)
-				x -= width;
-			else if (x < 0)
-				x += width;
-
 			float y = roundf(v1.y + i * step_y);
-			if (y >= height)
-				y -= height;
-			else if (y < 0)
-				y += height;
+
+			if (wrap) {
+				if (x >= width)
+					x -= width;
+				else if (x < 0)
+					x += width;
+				if (y >= height)
+					y -= height;
+				else if (y < 0)
+					y += height;
+			} else if (x >= width || x < 0 || y >= height || y < 0) {
+				continue;
+			}
 
 			set_pixel(x, y);
 		}
@@ -89,6 +102,8 @@ renderer_params_t renderer_init()
 	width = mode.hdisplay;
 	height = mode.vdisplay;
 
+	wrap = true;
+
 	const float aspect = (float)width / (float)height;
 	const float scale = (float)height / 2.0f;
 	view = (mat3_t) {
@@ -136,6 +151,11 @@ void renderer_swap()
 	back = (back + 1) & 1;
 }
 
+void renderer_set_wrap(bool enable)
+{
+	wrap = enable;
+}
+
 void renderer_clear()
 {
 	memset(fbs[back].buf, 0, fbs[back].size);