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#ifndef __EYES_INC
#define __EYES_INC
#if defined(_GIMMICK_EYES_00)
float eyes00_distance_from_sphere(float3 p, float3 c, float r)
{
return length(p - c) - r;
}
float eyes00_map(float3 p)
{
float t = _Time.y;
float theta = sin(_Time[0]) / 2;
float2x2 rot = float2x2(
cos(theta), -sin(theta),
sin(theta), cos(theta));
float dist = 1000 * 1000 * 1000;
#define Y_STEPS 5
for (int y = 0; y < Y_STEPS; y++)
{
const int yy = y - Y_STEPS/2;
#define X_STEPS 5
for (int x = 0; x < X_STEPS; x++)
{
const int xx = x - X_STEPS/2;
float2 pp = float2(xx * 2, yy * 2);
pp = mul(rot, pp);
float radius = cos((x + y + _Time[0]) * 3.14159) * 0.5 + 1;
float sphere = eyes00_distance_from_sphere(p, float3(pp.x, pp.y, 0.0), radius);
dist = min(dist, sphere);
dist += sin(5.0 * pp.x) * sin(5.0 * pp.y) * 0.5;
}
}
return dist;
}
float3 eyes00_calc_normal(in float3 p)
{
const float3 small_step = float3(0.0001, 0.0, 0.0);
float gradient_x = eyes00_map(p + small_step.xyy) - eyes00_map(p - small_step.xyy);
float gradient_y = eyes00_map(p + small_step.yxy) - eyes00_map(p - small_step.yxy);
float gradient_z = eyes00_map(p + small_step.yyx) - eyes00_map(p - small_step.yyx);
float3 normal = float3(gradient_x, gradient_y, gradient_z);
return normalize(normal);
}
float3 __eyes00_march(float3 ro, float3 rd, inout float3 normal)
{
float total_distance_traveled = 0.0;
const float MINIMUM_HIT_DISTANCE = 0.001;
const float MAXIMUM_TRACE_DISTANCE = 1000.0;
#define EYES00_MARCH_STEPS 10
float distance_to_closest;
float3 current_position;
for (int i = 0; i < EYES00_MARCH_STEPS; i++)
{
current_position = ro + total_distance_traveled * rd;
distance_to_closest = eyes00_map(current_position);
if (distance_to_closest < MINIMUM_HIT_DISTANCE)
{
break;
}
if (total_distance_traveled > MAXIMUM_TRACE_DISTANCE)
{
break;
}
total_distance_traveled += distance_to_closest;
}
if (distance_to_closest < MINIMUM_HIT_DISTANCE) {
normal = eyes00_calc_normal(current_position);
return float3(1.0, 1.0, 1.0);
}
return float3(0, 0, 0);
}
float4 eyes00_march(float2 uv, inout float3 normal)
{
uv = uv * 2.0 - 1.0;
float3 camera_position = float3(0.0, 0.0, -5.0);
float3 ro = camera_position;
float3 rd = float3(uv.x, uv.y, 1.0);
float3 shaded_color = __eyes00_march(ro, rd, normal);
return float4(shaded_color, 1.0);
}
#endif // _EYES
#endif // __EYES_INC
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