krampus
/
heliostat
generated from krampus/template-godot4
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Adjustments to threshold luminance calculation

This commit is contained in:
Rob Kelly 2024-07-23 14:52:32 -06:00
parent 772eeba531
commit 461281b3e2
2 changed files with 19 additions and 7 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
src/main.tscn
View File

@ -56,7 +56,7 @@ shader = ExtResource("1_rg2hr")
shader = ExtResource("1_bg1gg") shader = ExtResource("1_bg1gg")
shader_parameter/color_low = Color(0, 0, 0, 1) shader_parameter/color_low = Color(0, 0, 0, 1)
shader_parameter/color_hi = Color(1, 1, 1, 1) shader_parameter/color_hi = Color(1, 1, 1, 1)
shader_parameter/threshold = 0.455 shader_parameter/threshold = 0.174
shader_parameter/contrast = 1.0 shader_parameter/contrast = 1.0
shader_parameter/offset = 0.0 shader_parameter/offset = 0.0

24
src/shaders/threshold.gdshader
View File

@ -1,23 +1,35 @@
/* Binary threshold shader */ /* Binary threshold shader
* See https://stackoverflow.com/a/56678483
*/
shader_type canvas_item; shader_type canvas_item;
uniform vec4 color_low: source_color = vec4(0.0, 0.0, 0.0, 1.0); uniform vec4 color_low: source_color = vec4(0.0, 0.0, 0.0, 1.0);
uniform vec4 color_hi: source_color = vec4(1.0, 1.0, 1.0, 1.0); uniform vec4 color_hi: source_color = vec4(1.0, 1.0, 1.0, 1.0);
uniform float threshold: hint_range(0.0, 1.0) = 0.5; uniform float threshold: hint_range(0.0, 1.0) = 0.455;
uniform float contrast: hint_range(0.0, 1.0) = 1.0; uniform float contrast: hint_range(0.0, 1.0) = 1.0;
uniform float offset: hint_range(-1.0, 1.0) = 0.0; uniform float offset: hint_range(-1.0, 1.0) = 0.0;
float linearSRGB(float channel) {
if (channel <= 0.04045) {
return channel / 12.92;
} else {
return pow(((channel + 0.055) / 1.055), 2.4);
}
}
float luminance(vec3 color) {
return 0.2126 * linearSRGB(color.r) + 0.7152 * linearSRGB(color.g) + 0.0722 * linearSRGB(color.b);
}
void fragment() { void fragment() {
vec3 screen_col = texture(TEXTURE, UV).rgb; vec3 screen_col = texture(TEXTURE, UV).rgb;
// calculate pixel luminosity float Y = luminance(screen_col);
float luminosity = (screen_col.r * 0.299) + (screen_col.g * 0.587) + (screen_col.b * 0.114);
// adjust contrast & offset // adjust contrast & offset
luminosity = clamp((luminosity - 0.5 + offset) * contrast + 0.5, 0.0, 1.0); Y = clamp((Y - 0.5 + offset) * contrast + 0.5, 0.0, 1.0);
COLOR.rgba = luminosity > threshold ? color_hi : color_low; COLOR.rgba = Y > threshold ? color_hi : color_low;
} }