send image data to client

src/colour.h

@@ -2,22 +2,62 @@
 
 #include "rtweekend.h"
 
+// for writing to stdout
 #include <iostream>
 
-void write_colour(std::ostream &out, colour pixel_colour, int samples_per_pixel)
-{
-    auto r = pixel_colour.x();
-    auto g = pixel_colour.y();
-    auto b = pixel_colour.z();
+// for writing to socket
+#include <unistd.h>
 
-    // divide the colour total by the number of samples and gamme-correct for gamma=2.0
-    auto scale = 1.0 / samples_per_pixel;
+void correct_gamma(colour& pixel_colour, int samples)
+{
+    double r = pixel_colour.x();
+    double g = pixel_colour.y();
+    double b = pixel_colour.z();
+
+    // divide the colour total by the number of samples and gamma-correct for gamma=2.0
+    auto scale = 1.0 / samples;
     r = sqrt(scale * r);
     g = sqrt(scale * g);
     b = sqrt(scale * b);
 
+    pixel_colour = colour(r, g, b);
+}
+
+void write_colour_to_stream(std::ostream &out, colour pixel_colour, int samples_per_pixel)
+{
+    correct_gamma(pixel_colour, samples_per_pixel);
+
+    auto r = pixel_colour.x();
+    auto g = pixel_colour.y();
+    auto b = pixel_colour.z();
+    
     // write the translated [0,255] value of each colour component.
     out << static_cast<int>(256 * clamp(r, 0.0, 0.999)) << ' '
         << static_cast<int>(256 * clamp(g, 0.0, 0.999)) << ' '
         << static_cast<int>(256 * clamp(b, 0.0, 0.999)) << '\n';
 }
+
+int format_component(double component)
+{
+    return int(256 * clamp(component, 0.0, 0.999));
+}
+
+void write_colour_to_socket(int sockfd, colour pixel_colour, int samples_per_pixel)
+{
+    correct_gamma(pixel_colour, samples_per_pixel);
+
+    int r = format_component(pixel_colour.x());
+    int g = format_component(pixel_colour.y());
+    int b = format_component(pixel_colour.z());
+
+    // pack values
+    int len = 3;
+    char s[len];
+    sprintf(s, "%c%c%c", r, g, b);
+
+    int written = write(sockfd, s, len);
+    if (written < 0)
+    {
+        error("ERROR writing colour to socket");
+    }
+}

src/main.cpp

@@ -2,6 +2,13 @@
 
 #include "hittable_list.h"
 #include "sphere.h"
+
+void error(const char* message)
+{
+    perror(message);
+    exit(1);
+}
+
 #include "colour.h"
 #include "camera.h"
 #include "material.h"
@@ -15,9 +22,9 @@
 #include <sys/socket.h>
 #include <netinet/in.h>
 
-const double ASPECT_RATIO = 16.0 / 9.0;
-const int WIDTH = 1920;
-const int HEIGHT = static_cast<int>(WIDTH / ASPECT_RATIO);
+const double ASPECT_RATIO = 1.0;
+const unsigned int WIDTH = 256;
+const unsigned int HEIGHT = static_cast<int>(WIDTH / ASPECT_RATIO);
 const int SAMPLES_PER_PIXEL = 8;
 const int MAX_DEPTH = 5;
 
@@ -119,12 +126,6 @@ hittable_list random_scene()
     return world;
 }
 
-void error(const char* message)
-{
-    perror(message);
-    exit(1);
-}
-
 // file descriptor of the socket we're listening for connections on
 //
 // returns fd for the client connection
@@ -162,6 +163,18 @@ int wait_for_client(int& sockfd)
     serv_addr.sin_addr.s_addr = INADDR_ANY;
     serv_addr.sin_port = htons(64999);  // convert number from host to network byte order
 
+    // this is a bit of developer QoL so we can iterate more quickly
+    // TODO: make it possible to disable this debug/release build configuration
+    const int enable = 1;
+    if (setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR, &enable, sizeof(int)) < 0)
+    {
+        error("ERROR setsockopt(SO_REUSEADDR) failed");
+    }
+    if (setsockopt(sockfd, SOL_SOCKET, SO_REUSEPORT, &enable, sizeof(int)) < 0)
+    {
+        error("ERROR setsockopt(SO_REUSEPORT) failed");
+    }
+
     // bind the socket
     if (bind(sockfd, (struct sockaddr*)&serv_addr, sizeof(serv_addr)) < 0)
     {
@@ -185,6 +198,24 @@ void send_message(int sock, const char* message)
     printf("SEND %s\n", message);
 }
 
+void send_image_dimensions(int sock, unsigned int width, unsigned int height)
+{
+    // https://linux.die.net/man/3/htons
+    width = htonl(width);
+    height = htonl(height);
+
+    int written = write(sock, &width, sizeof(uint32_t));
+    if (written < 0)
+    {
+        error("ERROR writing width");
+    }
+    written = write(sock, &height, sizeof(uint32_t));
+    if (written < 0)
+    {
+        error("ERROR writing height");
+    }
+}
+
 int main()
 {
     int sockfd;
@@ -192,20 +223,9 @@ int main()
 
     printf("got a connection!\n");
 
-    // write a message to the client
-    send_message(newsockfd, "hi there!");
+    send_image_dimensions(newsockfd, WIDTH, HEIGHT);
 
-    // close client socket
-    close(newsockfd);
-
-    printf("closed client connection\n");
-
-    // close listening socket
-    close(sockfd);
-    // exit after all our connections are closed
-    exit(0);
-
-    std::cout << "P3\n" << WIDTH << ' ' << HEIGHT << "\n255\n";
+    //std::cout << "P3\n" << WIDTH << ' ' << HEIGHT << "\n255\n";
 
     hittable_list world = random_scene();
 
@@ -234,10 +254,23 @@ int main()
                 pixel_colour += ray_colour(r, world, MAX_DEPTH);
             }
 
-            write_colour(std::cout, pixel_colour, SAMPLES_PER_PIXEL);
+            //write_colour_to_stream(std::cout, pixel_colour, SAMPLES_PER_PIXEL);
+            write_colour_to_socket(newsockfd, pixel_colour, SAMPLES_PER_PIXEL);
         }
     }
 
-    std::cerr << "\nDone." << std::endl;
+    // close client socket
+    close(newsockfd);
+
+    printf("closed client connection\n");
+
+    // close listening socket
+    close(sockfd);
+
+    printf("closed listening socket\n");
+
+    printf("done!\n");
+
+    return 0;
 }
 

telescope.md

@@ -6,8 +6,8 @@ use rti1w as a base
 * [x] client establishes connection
 * [x] send a message to the client
 * [ ] move rendering out of main.cpp
-* [ ] send rendered image data to client
-* [ ] form image file on client
+* [x] send rendered image data to client
+* [x] form image file on client
 * [ ] client sends receiving port to server
 * [ ] client application sends command to send image
 * [ ] server receives imaging command