void Draw(PowderSim.MaterialID Type)
{
float2 cur_center = ((float3)Sim.transform.InverseTransformPoint(transform.position)).xy + 0.5f;
float cur_radius = ((float3)Sim.transform.InverseTransformVector(transform.localScale)).y / 2;
cur_center *= Sim.Resolution;
cur_radius *= Sim.Resolution.y;
// since moving the mouse fast results in in skipping pixels between frames
// we store the prev frames mouse position and step through all pixels on the line from prev frame and cur frame pos to never skip pixels
float dist = draw_prev_frame ? distance(cur_center, prev_center) : 0f;
float cur_dist = 0;
do
{
float t = dist != 0f ? cur_dist / dist : cur_dist;
float2 center = lerp(cur_center, prev_center, t);
float radius = lerp(cur_radius, prev_radius, t);
int2 a = clamp((int2)floor(center - radius), 0, Sim.Resolution);
int2 b = clamp((int2)ceil(center + radius), 0, Sim.Resolution);
for (int y = a.y; y < b.y; ++y)
{
for (int x = a.x; x < b.x; ++x)
{
if (distance(float2(x, y) + 0.5f, center) <= radius + 0.2f)
{
Sim.cells.Array[y, x] = new PowderSim.Cell {
mat = Type
}
}
;
}
}
cur_dist += 1;
} while (cur_dist < dist);
prev_center = cur_center;
prev_radius = cur_radius;
draw_prev_frame = true;
}
}
void Update()
{
var plane = new Plane(new Vector3(0, 0, -1), 0);
var ray = Camera.main.ScreenPointToRay(Input.mousePosition);
bool mouseHit = plane.Raycast(ray, out float dist);
MeshRenderer.enabled = mouseHit;
if (mouseHit)
{
float3 pos = ray.origin + ray.direction * dist;
transform.position = float3(pos.xy, transform.position.z);
}
{ // Update Tool Size
float size_log = log2(DrawSize);
size_log += Input.mouseScrollDelta.y * MouseScrollDeltaSens;
DrawSize = clamp(pow(2f, size_log), 1, 1024);
float Diameter = DrawSize * Sim.transform.localScale.y / Sim.Resolution.y; // size in world space of mouse cursor
transform.localScale = float3(Diameter);
MeshRenderer.material.SetFloat("_Thickness", 0.33f * 2 / DrawSize);
}
DrawMaterial = NumberKeyDown() ?? DrawMaterial;
if (Input.GetMouseButton(0)) // Draw
{
Draw(DrawMaterial);
}
else if (Input.GetMouseButton(1)) // Erase
{
Draw(PowderSim.MaterialID.AIR);
}
else
{
draw_prev_frame = false;
}
}
