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| #define MAX_ITERATIONS 10
#define MIN_DISTANCE 0.01f
#define PI 3.14159265358979f
float rand(float co) { return fract(sin(co*(91.3458)) * 47453.5453); }
struct Material
{
vec3 emission;
float intensity;
};
struct NearestData
{
float dist;
Material material;
};
float union_sdf(float d1, float d2)
{
return min(d1, d2);
}
float subtract_sdf(float d1, float d2)
{
return max(d1, -d2);
}
float sunion_sdf(float d1, float d2, float k)
{
float h = clamp( 0.5 + 0.5*(d2-d1)/k, 0.0, 1.0 );
return mix( d2, d1, h ) - k*h*(1.0-h);
}
float circle_sdf(vec2 point, vec2 pos, float radius)
{
return length(point - pos) - radius;
}
float box_sdf(vec2 point, vec2 center, vec2 size) {
center = point - center;
vec2 r = abs(center) - size;
return min(max(r.x, r.y),0.) + length(max(r,vec2(0,0)));
}
float segment_sdf(vec2 pos, vec2 a, vec2 b)
{
vec2 v = pos - a;
vec2 u = b - a;
float t = max(min(dot(v, u) / dot(u, u), 1.0f), 0.0f);
vec2 d = v - u * t;
return length(d);
}
void test_sample(inout NearestData nearest, Material material, float sample_distance)
{
if (sample_distance < nearest.dist)
{
nearest.dist = sample_distance;
nearest.material = material;
}
}
void sample_sdf(vec2 point, out NearestData nearest)
{
Material black_material;
Material white_material;
white_material.emission = vec3(1.0f);
white_material.intensity = 1.5f;
Material green_material;
green_material.emission = normalize(vec3(0.4, 0.6, 0.2));
green_material.intensity = 1.20f;
Material purple_material;
purple_material.emission = normalize(vec3(.6, 0.4, 0.8));
purple_material.intensity = 1.0f;
vec2 a = vec2(1.2, -0.75);
vec2 b = vec2(1.3, -0.5);
vec2 c = vec2(1.4, -0.7);
test_sample(nearest, white_material, segment_sdf(point, a, b));
test_sample(nearest, white_material, segment_sdf(point, b, c));
test_sample(nearest, white_material, segment_sdf(point, c, a));
test_sample(nearest, purple_material, box_sdf(point, vec2(1.4, 0.3), vec2(0.10f)));
test_sample(nearest, black_material, box_sdf(point, vec2(1.2, 0.3), vec2(0.050f)));
for (float i = 0.0f; i < 3.0f; i++)
{
test_sample(nearest, white_material, box_sdf(point, vec2(0, -i * 0.1f), vec2(0.0050f)));
}
test_sample(nearest, green_material, circle_sdf(point, vec2(-0.3, -0.3), 0.2f));
test_sample(nearest, black_material, circle_sdf(point, vec2(-1, 0.6), 0.6f));
test_sample(nearest, black_material, box_sdf(point, vec2(0.75, 0), vec2(0.5, 0.01)));
vec2 moon_pos = vec2(-0.8, -0.6);
float moon_radius = 0.3f;
float moon_distance = subtract_sdf(circle_sdf(point, moon_pos, moon_radius), circle_sdf(point, moon_pos + vec2(moon_radius * 0.5, 0), moon_radius));
test_sample(nearest, green_material, moon_distance);
vec2 box_pos = vec2(0.8, 0.3);
float box_size = 0.2;
float cut_size = 0.35f;
float main_cube_sd = box_sdf(point, box_pos, vec2(box_size));
float cut_horizontal_sd = box_sdf(point, box_pos - vec2(box_size * 0.5, 0), vec2(box_size * 2.0f, box_size * cut_size));
float cut_vertical_sd = box_sdf(point, box_pos - vec2(0.0f, box_size * 0.5), vec2(box_size * cut_size, box_size * 2.0f));
float cut_sphere_sd = circle_sdf(point, box_pos, 0.2f);
float k = .015f;
float cut_sd = sunion_sdf(cut_horizontal_sd, sunion_sdf(cut_vertical_sd, cut_sphere_sd, k), k);
float subtraction_box_sd = subtract_sdf(main_cube_sd, cut_sd);
test_sample(nearest, purple_material, subtraction_box_sd);
}
void ray_march(vec2 pos, vec2 direction, out vec3 color)
{
color = vec3(0);
for (int i = 0; i < MAX_ITERATIONS; i++)
{
NearestData nearest;
nearest.dist = 10e2;
sample_sdf(pos, nearest);
if (nearest.dist < MIN_DISTANCE)
{
color = nearest.material.emission * nearest.material.intensity;
return;
}
pos += direction * nearest.dist;
}
}
void mainImage( out vec4 fragColor, in vec2 fragCoord )
{
vec2 uv = fragCoord / iResolution.xy;
vec2 pos = 2.0f * (uv - 0.5f);
pos.x *= iResolution.x / iResolution.y;
float pixel_size = 1.0f / iResolution.x;
float pixels_offset = 2.0f;
float random_value = rand(iTime + pos.x * pos.y);
float random_angle = 2.0f * PI * rand(random_value);
vec2 offset = random_value * pixels_offset * pixel_size * vec2(cos(random_angle), sin(random_angle));
pos += offset;
vec3 accumulated_color = vec3(0);
float samples = 4.0f;
for (float i = 0.0f; i < samples; i++)
{
float angle = 2.0f * PI * (i + rand(pos.x * pos.y + iTime + i)) / samples;
vec2 direction = vec2(cos(angle), sin(angle));
vec3 sample_color;
ray_march(pos, direction, sample_color);
accumulated_color += sample_color;
}
vec3 color = accumulated_color / samples;
fragColor = vec4(color, 1.0) + texture(iChannel0, uv);
}
|
