[FEAT] Add canvas ppm part.

data/canvas.ppm

@@ -0,0 +1,49 @@
+P3
+# Created by GIMP version 2.10.30 PNM plug-in
+5 3
+255
+0
+0
+0
+255
+255
+255
+0
+0
+0
+255
+255
+255
+0
+0
+0
+255
+255
+255
+0
+0
+0
+255
+255
+255
+0
+0
+0
+255
+255
+255
+0
+0
+0
+255
+255
+255
+0
+0
+0
+255
+255
+255
+0
+0
+0

raytracing/src/canvas.cpp

@@ -78,3 +78,59 @@ bool Canvas::write_pixel(uint16_t a_pos_x, uint16_t a_pos_y, const Color &a_colo
     m_pixels[a_pos_x][a_pos_y] = a_color;
     return true;
 }
+
+/* ------------------------------------------------------------------------- */
+
+std::string Canvas::to_ppm(void)
+{
+    std::string the_result;
+
+    // Header
+    the_result = "P3\n";
+    the_result += std::to_string(m_width) + " " + std::to_string(m_height) + "\n";
+    the_result += "255\n";
+
+    for (int j = 0; j < m_height; j++)
+    {
+        uint16_t the_col_number = 0;
+        for (int i = 0; i < m_width; i++)
+        {
+            Color the_color;
+            the_color = m_pixels[i][j];
+
+            add_color_component(the_result, the_col_number, the_color.red_to_integer());
+            add_color_component(the_result, the_col_number, the_color.green_to_integer());
+            add_color_component(the_result, the_col_number, the_color.blue_to_integer());
+        }
+        the_result += "\n";
+        the_col_number = 0;
+    }
+
+    return the_result;
+}
+
+/* ------------------------------------------------------------------------- */
+
+bool Canvas::add_color_component(std::string &a_str_value, uint16_t &a_col_number, uint8_t a_color)
+{
+    std::string the_color_value;
+
+    the_color_value = std::to_string(a_color);
+
+    if ((the_color_value.length() + 1 + a_col_number) >= 70)
+    {
+        a_str_value += "\n";
+        a_col_number = 0;
+    }
+
+    if (a_col_number != 0)
+    {
+        a_str_value += " ";
+        a_col_number++;
+    }
+
+    a_str_value += the_color_value;
+    a_col_number += the_color_value.length();
+
+    return true;
+}

raytracing/src/canvas.h

@@ -28,9 +28,11 @@
 
 /* ------------------------------------------------------------------------- */
 
-#include <vector>
 #include <cstdint>
 
+#include <string>
+#include <vector>
+
 #include "color.h"
 
 /* ------------------------------------------------------------------------- */
@@ -49,6 +51,11 @@ namespace Raytracer
         const Color &pixel_at(uint16_t a_pos_x, uint16_t a_pos_y) const;
         bool write_pixel(uint16_t a_pos_x, uint16_t a_pos_y, const Color &a_color);
 
+        std::string to_ppm(void);
+
+    private:
+        bool add_color_component(std::string &a_str_value, uint16_t &a_col_number, uint8_t a_color);
+
     private:
         uint16_t m_width;
         uint16_t m_height;

raytracing/src/color.cpp

@@ -28,13 +28,14 @@
 
 /* ------------------------------------------------------------------------- */
 
+#include <cmath>
+#include <cstdio>
+
 #include "common.h"
 #include "color.h"
 
 using namespace Raytracer;
 
-#include <cstdio>
-
 /* ------------------------------------------------------------------------- */
 
 Color::Color(void) : m_red(0), m_green(0), m_blue(0)
@@ -174,3 +175,46 @@ double Color::blue(void) const
 {
     return m_blue;
 }
+
+/* ------------------------------------------------------------------------- */
+
+uint8_t Color::red_to_integer(void) const
+{
+    return color_to_integer(m_red);
+}
+
+/* ------------------------------------------------------------------------- */
+
+uint8_t Color::green_to_integer(void) const
+{
+    return color_to_integer(m_green);
+}
+
+/* ------------------------------------------------------------------------- */
+
+uint8_t Color::blue_to_integer(void) const
+{
+    return color_to_integer(m_blue);
+}
+
+/* ------------------------------------------------------------------------- */
+
+uint8_t Color::color_to_integer(double a_color) const
+{
+    uint8_t the_value;
+
+    if (a_color < 0)
+    {
+        the_value = 0;
+    }
+    else if (a_color > 1.0)
+    {
+        the_value = 255;
+    }
+    else
+    {
+        the_value = round(a_color * 255);
+    }
+
+    return the_value;
+}

raytracing/src/color.h

@@ -28,6 +28,10 @@
 
 /* ------------------------------------------------------------------------- */
 
+#include <cstdint>
+
+/* ------------------------------------------------------------------------- */
+
 namespace Raytracer
 {
     class Color
@@ -55,6 +59,13 @@ namespace Raytracer
         double green(void) const;
         double blue(void) const;
 
+        uint8_t red_to_integer(void) const;
+        uint8_t green_to_integer(void) const;
+        uint8_t blue_to_integer(void) const;
+
+    private:
+        uint8_t color_to_integer(double a_color) const;
+
     private:
         double m_red;
         double m_green;

tests/03_canvas.cpp

@@ -56,3 +56,53 @@ TEST_CASE("[Canvas] Writing pixels to a canvas", "[Canvas]")
 
     REQUIRE(c.pixel_at(2, 3) == red);
 }
+
+/* ------------------------------------------------------------------------- */
+
+TEST_CASE("[Canvas] Constructing the PPM pixel data", "[Canvas]")
+{
+    std::string ppm, the_ref_ppm;
+    Canvas c(5, 3);
+    Color c1(1.5, 0, 0);
+    Color c2(0, 0.5, 0);
+    Color c3(-0.5, 0, 1);
+
+    c.write_pixel(0, 0, c1);
+    c.write_pixel(2, 1, c2);
+    c.write_pixel(4, 2, c3);
+
+    ppm = c.to_ppm();
+
+    the_ref_ppm = "P3\n5 3\n255\n";
+    the_ref_ppm += "255 0 0 0 0 0 0 0 0 0 0 0 0 0 0\n";
+    the_ref_ppm += "0 0 0 0 0 0 0 128 0 0 0 0 0 0 0\n";
+    the_ref_ppm += "0 0 0 0 0 0 0 0 0 0 0 0 0 0 255\n";
+
+    REQUIRE(ppm == the_ref_ppm);
+}
+
+/* ------------------------------------------------------------------------- */
+
+TEST_CASE("[Canvas] Split long lines in PPM files", "[Canvas]")
+{
+    std::string ppm, the_ref_ppm;
+    Canvas c(10, 2);
+
+    for (int j = 0; j < 2; ++j)
+    {
+        for (int i = 0; i < 10; ++i)
+        {
+            c.write_pixel(i, j, Color(1, 0.8, 0.6));
+        }
+    }
+
+    ppm = c.to_ppm();
+
+    the_ref_ppm = "P3\n10 2\n255\n";
+    the_ref_ppm += "255 204 153 255 204 153 255 204 153 255 204 153 255 204 153 255 204\n";
+    the_ref_ppm += "153 255 204 153 255 204 153 255 204 153 255 204 153\n";
+    the_ref_ppm += "255 204 153 255 204 153 255 204 153 255 204 153 255 204 153 255 204\n";
+    the_ref_ppm += "153 255 204 153 255 204 153 255 204 153 255 204 153\n";
+
+    REQUIRE(ppm == the_ref_ppm);
+}