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project-hood/shaders/quantize.gdshaderinc
2025-10-15 00:18:23 +02:00

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group_uniforms Quantization;
/**Pixel resolution scale (0 is bypass)*/
uniform int quantize_size : hint_range(0,100) = 1;
/**Pixels are snapped based on world coordinates vs local coordinates.*/
uniform bool snap_to_world;
/**Auto-scales the quantize size when zoom is < 1, preventing subpixel artifacts*/
uniform bool limit_subpixels = true;
group_uniforms;
varying mat4 v_model_matrix;
varying mat4 v_alt_matrix;
varying vec2 v_vertex;
varying flat int v_quant_size;
varying flat vec4 v_texture_data;
const float EPSILON = 0.0001;
int getQuantizeSize(float in_zoom) {
int q_size = quantize_size;
if (limit_subpixels && in_zoom < 1.) {
q_size = int(round(float(quantize_size) * (1. / in_zoom)));
}
return q_size;
}
vec2 _snap(vec2 in_uv, float in_q_size) {
return (floor(in_uv / in_q_size) + 0.5) * in_q_size;
}
vec4 getQuantizeScreenUV(vec2 in_screen_uv) {
vec4 result;
if (v_quant_size == 0) {
result.xy = in_screen_uv;
result.zw = (v_model_matrix * vec4(v_vertex, 0, 1)).xy;
return result;
}
if (snap_to_world) {
vec2 uv = (v_model_matrix * vec4(v_vertex, 0, 1)).xy;
result.zw = uv + EPSILON;
uv = _snap(uv, float(v_quant_size));
uv = (v_alt_matrix * vec4(uv, 0,1)).xy;
uv = uv * 0.5 + 0.5;
result.xy = uv;
return result;
} else {
vec2 origin_uv = v_texture_data.xy;
vec2 quant_pixel_size = v_texture_data.zw;
vec2 uv = in_screen_uv - origin_uv;
uv = (floor(uv / quant_pixel_size) + 0.5) * quant_pixel_size;
uv = uv + origin_uv;
vec2 clipXY = uv * 2.0 - 1.;
vec2 world_pos = (v_alt_matrix * vec4(clipXY, 0.0, 1.0)).xy;
result.zw = world_pos + EPSILON;
result.xy = uv;
return result;
}
}
vec4 getQuantizeTextureUV(vec2 in_uv) {
vec4 result;
vec2 texture_size = v_texture_data.xy;
vec2 flip = v_texture_data.zw;
if (v_quant_size == 0) {
result.xy = in_uv;
result.zw = (v_model_matrix * vec4(in_uv * texture_size, 0, 1)).xy;
return result;
}
vec2 offset;
float q = float(v_quant_size);
vec2 uv = in_uv;
uv = mix(uv, 1.0 - uv, flip);
if (snap_to_world) {
vec2 inv_texture_size = 1. / texture_size;
offset = v_vertex * inv_texture_size;
offset = uv - offset;
uv -= offset;
uv *= texture_size;
uv = (v_model_matrix * vec4(uv, 0, 1)).xy;
result.zw = uv;
uv = _snap(uv, q);
uv = (v_alt_matrix * vec4(uv, 0, 1)).xy;
uv *= inv_texture_size;
uv = offset + uv;
} else {
uv *= texture_size;
result.zw = uv;
uv = _snap(uv, q);
uv /= texture_size;
}
uv = mix(uv, 1.0 - uv, flip);
result.xy = uv + EPSILON;
return result;
}