Add gaussian kernal and gaussian blur to model

Author: Michael Bassili

tgaimage.cpp

@@ -1,5 +1,6 @@
 #include <iostream>
 #include <fstream>
+#include <cmath>
 #include <string.h>
 #include <time.h>
 #include <math.h>
@@ -354,3 +355,50 @@ bool TGAImage::scale(int w, int h) {
     return true;
 }
 
+float* gaussian_kernel(const int radius) {
+    int size = (radius*2)+1;
+    float norm = 1.f/(std::sqrt(2.f*M_PI)*radius);
+    float* gaussian_kernel = new float[size];
+    float coeff = -1.f/(2.f*radius*radius);
+
+    float sum = 0.f;
+    for (int i=0; i<size; i++) {
+        gaussian_kernel[i] = norm * exp(powl(i-radius,2)*coeff);
+        sum += gaussian_kernel[i];
+    }
+    for (int i=size; i--; gaussian_kernel[i] /= sum);
+    return gaussian_kernel;
+}
+
+void TGAImage::gaussian_blur(const int radius) {
+    float *kernel = gaussian_kernel(radius);
+    TGAImage tmp(*this);
+    int size = (radius*2)+1;
+    for (int j=size; j<get_height(); j++) {
+        for (int i=0; i<get_width(); i++) {
+            float BGRA[4] = {0,0,0,0};
+            for (int k=0; k<size; k++){
+                TGAColor c = get(i, j-size+k);
+                for (int d=0; d<bytespp; d++) BGRA[d] += float(c[d])*kernel[k];
+            }
+            unsigned char cBGRA[4];
+            for (int i=4; i--; cBGRA[i] = (unsigned char)BGRA[i]);
+            tmp.set(i, j, TGAColor(cBGRA, bytespp));
+        }
+    }
+    for (int j=0; j<get_height(); j++) {
+        for (int i=size; i<get_width(); i++) {
+            float BGRA[4] = {0,0,0,0};
+            for (int k=0; k<size; k++){
+                TGAColor c = tmp.get(i-size+k, j);
+                for (int d=0; d<bytespp; d++) BGRA[d] += float(c[d])*kernel[k];
+            }
+            unsigned char cBGRA[4];
+            for (int i=4; i--; cBGRA[i] = (unsigned char)BGRA[i]);
+            set(i, j, TGAColor(cBGRA, bytespp));
+        }
+    }
+    delete [] kernel;
+}
+
+

tgaimage.h

@@ -92,6 +92,7 @@ class TGAImage {
     int get_bytespp();
     unsigned char *buffer();
     void clear();
+    void gaussian_blur(const int radius);
 };
 
 #endif //__IMAGE_H__