80 lines
1.9 KiB
Plaintext
80 lines
1.9 KiB
Plaintext
#version 330 core
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// Interpolated values from the vertex shaders
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in vec2 UV;
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// Ouput data
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layout(location = 0) out vec3 color;
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//out vec3 color;
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// Values that stay constant for the whole mesh.
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uniform sampler2D foreground;
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// Relative width/height of a pixel
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uniform float pixWidth;
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uniform float pixHeight;
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// Pixel state
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int IS_BACKGROUND = 0;
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int IS_UNDEFINED = 1;
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int IS_FOREGROUND = 2;
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int UNSET = -1;
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vec3 greenValue = vec3(0.0f, 1.0f, 0.0f);
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vec3 difference = vec3(40.0f/255.0f);
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int radius = 10;
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vec3 getColor(vec2 uvCoord) {
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return texture(foreground, uvCoord).rgb;
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}
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bool isBackground(vec3 c) {
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if (all( lessThanEqual(c, greenValue+difference)) &&
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all(greaterThanEqual(c, greenValue-difference))
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) {
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return true;
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} else {
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return false;
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}
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}
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void main(){
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int status = UNSET;
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for(int w=-radius;w<=radius;w++){
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for(int h=-radius;h<=radius;h++){
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if (w+h==-radius*2) { // first pixel
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if (isBackground(getColor(UV+vec2(pixWidth*w, pixHeight*h)))) {
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status = IS_BACKGROUND;
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} else {
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status = IS_FOREGROUND;
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}
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} else { // other pixels
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if (isBackground(getColor(UV+vec2(pixWidth*w, pixHeight*h)))) {
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if (status != IS_BACKGROUND) {
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status = IS_UNDEFINED;
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w=100000;
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break;
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}
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} else {
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if (status != IS_FOREGROUND) {
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status = IS_UNDEFINED;
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w=100000;
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break;
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}
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}
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}
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}
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}
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if (status == IS_BACKGROUND) {
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color = vec3(0.0f); // black
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} else if (status == IS_FOREGROUND) {
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color = vec3(1.0f); // white
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} else {
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color = vec3(0.5f); // gray
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}
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}
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