Fold image_texture class into texture.h header

Resolves #295

Author: hollasch

src/TheNextWeek/main.cc

@@ -12,7 +12,6 @@
 #include "common/rtweekend.h"
 #include "common/camera.h"
 #include "common/rtw_stb_image.h"
-#include "common/surface_texture.h"
 #include "common/texture.h"
 #include "box.h"
 #include "bvh.h"
@@ -44,7 +43,7 @@ hittable *earth() {
     //unsigned char *tex_data = stbi_load("tiled.jpg", &nx, &ny, &nn, 0);
     unsigned char *tex_data = stbi_load("earthmap.jpg", &nx, &ny, &nn, 0);
     material *mat = new lambertian(new image_texture(tex_data, nx, ny));
-    return new sphere(vec3(0,0, 0), 2, mat);
+    return new sphere(vec3(0, 0, 0), 2, mat);
 }
 
 hittable *two_spheres() {

src/common/surface_texture.h

@@ -20,6 +20,7 @@ class texture  {
         virtual vec3 value(double u, double v, const vec3& p) const = 0;
 };
 
+
 class constant_texture : public texture {
     public:
         constant_texture() {}
@@ -32,6 +33,7 @@ class constant_texture : public texture {
         vec3 color;
 };
 
+
 class checker_texture : public texture {
     public:
         checker_texture() {}
@@ -65,4 +67,30 @@ class noise_texture : public texture {
         double scale;
 };
 
+
+class image_texture : public texture {
+    public:
+        image_texture() {}
+        image_texture(unsigned char *pixels, int A, int B) : data(pixels), nx(A), ny(B) {}
+
+        virtual vec3 value(double u, double v, const vec3& p) const {
+            auto i = static_cast<int>((  u)*nx);
+            auto j = static_cast<int>((1-v)*ny-0.001);
+
+            if (i < 0) i = 0;
+            if (j < 0) j = 0;
+            if (i > nx-1) i = nx-1;
+            if (j > ny-1) j = ny-1;
+
+            auto r = static_cast<int>(data[3*i + 3*nx*j+0]) / 255.0;
+            auto g = static_cast<int>(data[3*i + 3*nx*j+1]) / 255.0;
+            auto b = static_cast<int>(data[3*i + 3*nx*j+2]) / 255.0;
+            return vec3(r, g, b);
+        }
+
+        unsigned char *data;
+        int nx, ny;
+};
+
+
 #endif