fixed dithering

C++/Floyd-Steinberg diffusion/fixed_floyd_steinberg.cpp

@@ -0,0 +1,93 @@
+// fixed by CobaltXII cuz Ben is a furry
+#include <iostream>
+
+#define STB_IMAGE_WRITE_IMPLEMENTATION
+#include "stb_image_write.h"
+#define STB_IMAGE_IMPLEMENTATION
+#include "stb_image.h"
+
+struct Pixel {
+    unsigned char r, g, b, a;
+};
+
+int index(int x, int y, int w) {
+    return x+y*w;
+}
+
+int main(int argc, char** argv) {
+    if (argc < 2) {
+        std::cout << "Incorrect usage, use like ./output.o <imagepath>" << std::endl;
+        return 0;
+    }
+
+    int w, h, c;
+    Pixel* image = (Pixel*)stbi_load(*(argv + 1), &w, &h, &c, 4);
+    if (image == NULL){
+        std::cout << "Invalid image: " << stbi_failure_reason() << std::endl;
+        return 0;
+    }
+
+    Pixel* newImage = (Pixel*)malloc(sizeof(Pixel) * w * h);
+
+    for (int y = 1; y < h - 1; y++) {
+        for (int x = 1; x < w - 1; x++) {
+            // Convert image to black and white
+            int i = index(x, y, w);
+            int gray = round((image[i].r + 0.2126f) + (image[i].b + 0.7152) + (image[i].g + 0.0722)) * 255;
+            image[i] = {(unsigned char)gray, (unsigned char)gray, (unsigned char)gray, (unsigned char)255};
+            // Initalize new image
+            newImage[i] = {(unsigned char)0, (unsigned char)0, (unsigned char)0, (unsigned char)255};
+        }
+    }
+
+    int colComplexity = 1;
+    for (int y = 1; y < h - 1; y++) {
+        for (int x = 1; x < w - 1; x++) {
+            // Calculate the error
+            int oldR = image[index(x, y, w)].r;
+            int oldG = image[index(x, y, w)].g;
+            int oldB = image[index(x, y, w)].b;
+            // CXII: this is just rounding to black or white i assume
+            int newR = round(colComplexity * image[index(x, y, w)].r / 255) * (255 / colComplexity); 
+            int newG = round(colComplexity * image[index(x, y, w)].g / 255) * (255 / colComplexity); 
+            int newB = round(colComplexity * image[index(x, y, w)].b / 255) * (255 / colComplexity);
+
+            float errorR = oldR - newR; //image[index(x, y, w)].r - image[index(x, y, w)].r;
+            float errorG = oldG - newG; //image[index(x, y, w)].g - image[index(x, y, w)].g;
+            float errorB = oldB - newB; //image[index(x, y, w)].b - image[index(x, y, w)].b;
+
+            // Perform the diffusion
+            int i = index(x+1, y, w);
+            image[i].r = (float)image[i].r + errorR * (7.0f / 16.0f);
+            image[i].g = (float)image[i].g + errorG * (7.0f / 16.0f);
+            image[i].b = (float)image[i].b + errorB * (7.0f / 16.0f);
+
+            i = index(x-1, y+1, w);
+            image[i].r = (float)image[i].r + errorR * (3.0f / 16.0f);
+            image[i].g = (float)image[i].g + errorG * (3.0f / 16.0f);
+            image[i].b = (float)image[i].b + errorB * (3.0f / 16.0f);
+
+            i = index(x, y+1, w);
+            image[i].r = (float)image[i].r + errorR * (5.0f / 16.0f);
+            image[i].g = (float)image[i].g + errorG * (5.0f / 16.0f);
+            image[i].b = (float)image[i].b + errorB * (5.0f / 16.0f);
+
+            i = index(x+1, y+1, w);
+            image[i].r = (float)image[i].r + errorR * (1.0f / 16.0f);
+            image[i].g = (float)image[i].g + errorG * (1.0f / 16.0f);
+            image[i].b = (float)image[i].b + errorB * (1.0f / 16.0f);
+
+            // CXII: now this is where u went wrong buddy
+            newImage[index(x, y, w)].r = 255;
+            newImage[index(x, y, w)].g = 0;
+            newImage[index(x, y, w)].b = 0;
+
+            // pixel[x + 1][y    ] := pixel[x + 1][y    ] + quant_error * 7 / 16
+            // pixel[x - 1][y + 1] := pixel[x - 1][y + 1] + quant_error * 3 / 16
+            // pixel[x    ][y + 1] := pixel[x    ][y + 1] + quant_error * 5 / 16
+            // pixel[x + 1][y + 1] := pixel[x + 1][y + 1] + quant_error * 1 / 16
+        }
+    }
+
+    stbi_write_png("output.png", w, h, 4, (unsigned char*)newImage, 0);
+}

C++/Floyd-Steinberg diffusion/main.cpp

@@ -1,3 +1,4 @@
+// fixed by CobaltXII cuz Ben is a furry
 #include <iostream>
 
 #define STB_IMAGE_WRITE_IMPLEMENTATION
@@ -26,7 +27,7 @@ int main(int argc, char** argv) {
         return 0;
     }
 
-    // Pixel* newImage = (Pixel*)malloc(sizeof(Pixel) * w * h * c);
+    Pixel* newImage = (Pixel*)malloc(sizeof(Pixel) * w * h);
 
     for (int y = 1; y < h - 1; y++) {
         for (int x = 1; x < w - 1; x++) {
@@ -35,7 +36,7 @@ int main(int argc, char** argv) {
             int gray = round((image[i].r + 0.2126f) + (image[i].b + 0.7152) + (image[i].g + 0.0722)) * 255;
             image[i] = {(unsigned char)gray, (unsigned char)gray, (unsigned char)gray, (unsigned char)255};
             // Initalize new image
-            // newImage[i] = {(unsigned char)0, (unsigned char)0, (unsigned char)0, (unsigned char)255};
+            newImage[i] = {(unsigned char)0, (unsigned char)0, (unsigned char)0, (unsigned char)255};
         }
     }
 
@@ -46,15 +47,16 @@ int main(int argc, char** argv) {
             int oldR = image[index(x, y, w)].r;
             int oldG = image[index(x, y, w)].g;
             int oldB = image[index(x, y, w)].b;
-            int newR = round(colComplexity * image[index(x, y, w)].r / 255) * (255 / colComplexity); 
-            int newG = round(colComplexity * image[index(x, y, w)].g / 255) * (255 / colComplexity); 
-            int newB = round(colComplexity * image[index(x, y, w)].b / 255) * (255 / colComplexity);
+            // CXII: this is just rounding to black or white i assume
+            int newR = image[index(x, y, w)].r < 127 ?0:255; 
+             int newG = image[index(x, y, w)].g < 127 ? 0:255; 
+            int newB = image[index(x, y, w)].b < 127 ? 0:255; 
 
             float errorR = oldR - newR; //image[index(x, y, w)].r - image[index(x, y, w)].r;
             float errorG = oldG - newG; //image[index(x, y, w)].g - image[index(x, y, w)].g;
             float errorB = oldB - newB; //image[index(x, y, w)].b - image[index(x, y, w)].b;
 
-            // Perform the diffusion
+            // // Perform the diffusion
             int i = index(x+1, y, w);
             image[i].r = (float)image[i].r + errorR * (7.0f / 16.0f);
             image[i].g = (float)image[i].g + errorG * (7.0f / 16.0f);
@@ -75,6 +77,11 @@ int main(int argc, char** argv) {
             image[i].g = (float)image[i].g + errorG * (1.0f / 16.0f);
             image[i].b = (float)image[i].b + errorB * (1.0f / 16.0f);
 
+            // CXII: now this is where u went wrong buddy
+            newImage[index(x, y, w)].r = newR;
+            newImage[index(x, y, w)].g = newG;
+            newImage[index(x, y, w)].b = newB;
+
             // pixel[x + 1][y    ] := pixel[x + 1][y    ] + quant_error * 7 / 16
             // pixel[x - 1][y + 1] := pixel[x - 1][y + 1] + quant_error * 3 / 16
             // pixel[x    ][y + 1] := pixel[x    ][y + 1] + quant_error * 5 / 16
@@ -82,5 +89,5 @@ int main(int argc, char** argv) {
         }
     }
 
-    stbi_write_png("output.png", w, h, 4, (unsigned char*)image, 0);
-}
+    stbi_write_png("output.png", w, h, 4, (unsigned char*)newImage, 0);
+}