crude 3d rendering

tinyraycaster.cpp

@@ -35,16 +35,16 @@ void draw_rectangle(std::vector<uint32_t> &img, const size_t img_w, const size_t
         for (size_t j=0; j<h; j++) {
             size_t cx = x+i;
             size_t cy = y+j;
-            assert(cx<img_w && cy<img_h);
+            if (cx>=img_w || cy>=img_h) continue; // no need to check negative values, (unsigned variables)
             img[cx + cy*img_w] = color;
         }
     }
 }
 
 int main() {
-    const size_t win_w = 512; // image width
-    const size_t win_h = 512; // image height
-    std::vector<uint32_t> framebuffer(win_w*win_h, 255); // the image itself, initialized to white
+    const size_t win_w = 1024; // image width
+    const size_t win_h = 512;  // image height
+    std::vector<uint32_t> framebuffer(win_w*win_h, pack_color(255, 255, 255)); // the image itself, initialized to white
 
     const size_t map_w = 16; // map width
     const size_t map_h = 16; // map height
@@ -70,16 +70,7 @@ int main() {
     float player_a = 1.523; // player view direction
     const float fov = M_PI/3.; // field of view
 
-    for (size_t j = 0; j<win_h; j++) { // fill the screen with color gradients
-        for (size_t i = 0; i<win_w; i++) {
-            uint8_t r = 255*j/float(win_h); // varies between 0 and 255 as j sweeps the vertical
-            uint8_t g = 255*i/float(win_w); // varies between 0 and 255 as i sweeps the horizontal
-            uint8_t b = 0;
-            framebuffer[i+j*win_w] = pack_color(r, g, b);
-        }
-    }
-
-    const size_t rect_w = win_w/map_w;
+    const size_t rect_w = win_w/(map_w*2);
     const size_t rect_h = win_h/map_h;
     for (size_t j=0; j<map_h; j++) { // draw the map
         for (size_t i=0; i<map_w; i++) {
@@ -90,20 +81,21 @@ int main() {
         }
     }
 
-    // draw the player on the map
-    draw_rectangle(framebuffer, win_w, win_h, player_x*rect_w, player_y*rect_h, 5, 5, pack_color(255, 255, 255));
-
-    for (size_t i=0; i<win_w; i++) { // draw the visibility cone
-        float angle = player_a-fov/2 + fov*i/float(win_w);
-
+    for (size_t i=0; i<win_w/2; i++) { // draw the visibility cone AND the "3D" view
+        float angle = player_a-fov/2 + fov*i/float(win_w/2);
         for (float t=0; t<20; t+=.05) {
             float cx = player_x + t*cos(angle);
             float cy = player_y + t*sin(angle);
-            if (map[int(cx)+int(cy)*map_w]!=' ') break;
 
             size_t pix_x = cx*rect_w;
             size_t pix_y = cy*rect_h;
-            framebuffer[pix_x + pix_y*win_w] = pack_color(255, 255, 255);
+            framebuffer[pix_x + pix_y*win_w] = pack_color(160, 160, 160); // this draws the visibility cone
+
+            if (map[int(cx)+int(cy)*map_w]!=' ') { // our ray touches a wall, so draw the vertical column to create an illusion of 3D
+                size_t column_height = win_h/t;
+                draw_rectangle(framebuffer, win_w, win_h, win_w/2+i, win_h/2-column_height/2, 1, column_height, pack_color(0, 255, 255));
+                break;
+            }
         }
     }