1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
|
/* clang-format off */
#[modes]
mode_load = #define MODE_LOAD
mode_load_shrink = #define MODE_LOAD_SHRINK
mode_process = #define MODE_PROCESS
mode_store = #define MODE_STORE
mode_store_shrink = #define MODE_STORE_SHRINK
#[specializations]
#[vertex]
layout(location = 0) in vec2 vertex_attrib;
/* clang-format on */
uniform ivec2 size;
uniform int stride;
uniform int shift;
uniform ivec2 base_size;
void main() {
gl_Position = vec4(vertex_attrib, 1.0, 1.0);
}
/* clang-format off */
#[fragment]
#define SDF_MAX_LENGTH 16384.0
#if defined(MODE_LOAD) || defined(MODE_LOAD_SHRINK)
uniform lowp sampler2D src_pixels;//texunit:0
#else
uniform highp isampler2D src_process;//texunit:0
#endif
uniform ivec2 size;
uniform int stride;
uniform int shift;
uniform ivec2 base_size;
#if defined(MODE_LOAD) || defined(MODE_LOAD_SHRINK) || defined(MODE_PROCESS)
layout(location = 0) out ivec4 distance_field;
#else
layout(location = 0) out vec4 distance_field;
#endif
vec4 float_to_vec4(float p_float) {
highp vec4 comp = fract(p_float * vec4(255.0 * 255.0 * 255.0, 255.0 * 255.0, 255.0, 1.0));
comp -= comp.xxyz * vec4(0.0, 1.0 / 255.0, 1.0 / 255.0, 1.0 / 255.0);
return comp;
}
void main() {
ivec2 pos = ivec2(gl_FragCoord.xy);
#ifdef MODE_LOAD
bool solid = texelFetch(src_pixels, pos, 0).r > 0.5;
distance_field = solid ? ivec4(ivec2(-32767), 0, 0) : ivec4(ivec2(32767), 0, 0);
#endif
#ifdef MODE_LOAD_SHRINK
int s = 1 << shift;
ivec2 base = pos << shift;
ivec2 center = base + ivec2(shift);
ivec2 rel = ivec2(32767);
float d = 1e20;
int found = 0;
int solid_found = 0;
for (int i = 0; i < s; i++) {
for (int j = 0; j < s; j++) {
ivec2 src_pos = base + ivec2(i, j);
if (any(greaterThanEqual(src_pos, base_size))) {
continue;
}
bool solid = texelFetch(src_pixels, src_pos, 0).r > 0.5;
if (solid) {
float dist = length(vec2(src_pos - center));
if (dist < d) {
d = dist;
rel = src_pos;
}
solid_found++;
}
found++;
}
}
if (solid_found == found) {
//mark solid only if all are solid
rel = ivec2(-32767);
}
distance_field = ivec4(rel, 0, 0);
#endif
#ifdef MODE_PROCESS
ivec2 base = pos << shift;
ivec2 center = base + ivec2(shift);
ivec2 rel = texelFetch(src_process, pos, 0).xy;
bool solid = rel.x < 0;
if (solid) {
rel = -rel - ivec2(1);
}
if (center != rel) {
//only process if it does not point to itself
const int ofs_table_size = 8;
const ivec2 ofs_table[ofs_table_size] = ivec2[](
ivec2(-1, -1),
ivec2(0, -1),
ivec2(+1, -1),
ivec2(-1, 0),
ivec2(+1, 0),
ivec2(-1, +1),
ivec2(0, +1),
ivec2(+1, +1));
float dist = length(vec2(rel - center));
for (int i = 0; i < ofs_table_size; i++) {
ivec2 src_pos = pos + ofs_table[i] * stride;
if (any(lessThan(src_pos, ivec2(0))) || any(greaterThanEqual(src_pos, size))) {
continue;
}
ivec2 src_rel = texelFetch(src_process, src_pos, 0).xy;
bool src_solid = src_rel.x < 0;
if (src_solid) {
src_rel = -src_rel - ivec2(1);
}
if (src_solid != solid) {
src_rel = ivec2(src_pos << shift); //point to itself if of different type
}
float src_dist = length(vec2(src_rel - center));
if (src_dist < dist) {
dist = src_dist;
rel = src_rel;
}
}
}
if (solid) {
rel = -rel - ivec2(1);
}
distance_field = ivec4(rel, 0, 0);
#endif
#ifdef MODE_STORE
ivec2 rel = texelFetch(src_process, pos, 0).xy;
bool solid = rel.x < 0;
if (solid) {
rel = -rel - ivec2(1);
}
float d = length(vec2(rel - pos));
if (solid) {
d = -d;
}
d /= SDF_MAX_LENGTH;
d = clamp(d, -1.0, 1.0);
distance_field = float_to_vec4(d*0.5+0.5);
#endif
#ifdef MODE_STORE_SHRINK
ivec2 base = pos << shift;
ivec2 center = base + ivec2(shift);
ivec2 rel = texelFetch(src_process, pos, 0).xy;
bool solid = rel.x < 0;
if (solid) {
rel = -rel - ivec2(1);
}
float d = length(vec2(rel - center));
if (solid) {
d = -d;
}
d /= SDF_MAX_LENGTH;
d = clamp(d, -1.0, 1.0);
distance_field = float_to_vec4(d*0.5+0.5);
#endif
}
|