From 594138cf96a2411e7e99ab7ac5a9fdd61fa42674 Mon Sep 17 00:00:00 2001
From: erikgoe <erikgoe@users.noreply.github.com>
Date: Sun, 24 Jan 2021 21:41:23 +0100
Subject: [PATCH] Make final polishing (challenge end)

---
 terminalDonut.cpp | 27 ++++++++++++++++-----------
 1 file changed, 16 insertions(+), 11 deletions(-)

diff --git a/terminalDonut.cpp b/terminalDonut.cpp
index d8ee880..9338edd 100644
--- a/terminalDonut.cpp
+++ b/terminalDonut.cpp
@@ -16,6 +16,7 @@ struct Vector3 {
     Vector3 operator*( const float &factor ) const { return Vector3{ x * factor, y * factor, z * factor }; }
 
     float dot_product( const Vector3 &other ) const { return x * other.x + y * other.y + z * other.z; }
+    float length() const { return std::sqrt( this->dot_product( *this ) ); }
 };
 
 struct Matrix3 {
@@ -46,16 +47,16 @@ struct Matrix3 {
 
 int main() {
     // Create a simple ring in the xy-plane
-    const size_t RING_SECTIONS = 32;
+    const size_t RING_SECTIONS = 64;
     Vector3 basic_ring[RING_SECTIONS];
     for ( size_t i = 0; i < RING_SECTIONS; i++ )
         basic_ring[i] = Vector3::in_xy_circle( i * M_PI * 2 / RING_SECTIONS );
 
     // Create the torus
-    const size_t TORUS_SECTIONS = 128;
+    const size_t TORUS_SECTIONS = 256;
     Vector3 torus[RING_SECTIONS * TORUS_SECTIONS];
     Vector3 normals[RING_SECTIONS * TORUS_SECTIONS];
-    Vector3 index = Vector3{ 2.5f, 0.f, 0.f };
+    Vector3 index = Vector3{ 2.f, 0.f, 0.f };
     for ( size_t i = 0; i < TORUS_SECTIONS; i++ ) {
         auto rotation = Matrix3::rotationAroundY( i * M_PI * 2 / TORUS_SECTIONS );
         for ( size_t j = 0; j < RING_SECTIONS; j++ ) {
@@ -71,13 +72,15 @@ int main() {
     float render_buffer[BUFFER_SIZE_X][BUFFER_SIZE_Y];
     float z_buffer[BUFFER_SIZE_X][BUFFER_SIZE_Y];
     Vector3 center = Vector3{ 32.f, 32.f, 32.f };
-    Vector3 light_dir = Vector3::in_xy_circle( -M_PI / 2.f );
+    Vector3 light_dir = Vector3{ -0.4f, -1.f, 0.4f };
+    light_dir = light_dir * ( 1.f / light_dir.length() );
     float time = 0.f;
 
     // Main loop
     while ( running ) {
-        auto x_rotation = Matrix3::rotationAroundX( M_PI / 2.f * std::sin( time * 1.2 ) );
-        auto y_rotation = Matrix3::rotationAroundY( M_PI / 2.f * std::sin( time + 1.2 ) );
+        auto x_rotation = Matrix3::rotationAroundX( M_PI / 2.f * std::sin( time * 1.5 ) );
+        auto y_rotation = Matrix3::rotationAroundY( M_PI / 2.f * std::sin( time * 1.5 + 1.5 ) );
+        auto z_rotation = Matrix3::rotationAroundZ( M_PI / 2.f * std::sin( time + 1.5 ) );
         // Clear buffer
         for ( size_t y = 0; y < BUFFER_SIZE_Y; y++ ) {
             for ( size_t x = 0; x < BUFFER_SIZE_X; x++ ) {
@@ -88,15 +91,17 @@ int main() {
 
         // Rotate and project the torus
         for ( size_t i = 0; i < TORUS_SECTIONS * RING_SECTIONS; i++ ) {
-            auto final_position = y_rotation * ( x_rotation * torus[i] );
-            auto final_normal = y_rotation * ( x_rotation * normals[i] );
-            final_position = final_position * 6.f + center; // adjust position into viewport
+            auto final_position = z_rotation * ( y_rotation * ( x_rotation * torus[i] ) );
+            auto final_normal = z_rotation * ( y_rotation * ( x_rotation * normals[i] ) );
+            final_position = final_position * 8.f + center; // adjust position into viewport
             int x = static_cast<int>( std::round( final_position.x ) );
             int y = static_cast<int>( std::round( final_position.y * character_ratio ) );
             int z = static_cast<int>( std::round( final_position.z ) );
-            if ( z_buffer[x][y] + 0.1 < z ) {
+            if ( z_buffer[x][y] + 0.1f < z ) {
                 render_buffer[x][y] = final_normal.dot_product( light_dir );
                 z_buffer[x][y] = final_position.z;
+            } else if ( std::abs( z_buffer[x][y] - z ) < 0.1f ) {
+                render_buffer[x][y] = ( render_buffer[x][y] + final_normal.dot_product( light_dir ) ) / 2.f;
             }
         }
 
@@ -117,7 +122,7 @@ int main() {
 
         // Ensure ~60 FPS
         std::this_thread::sleep_for( std::chrono::milliseconds( 16 ) );
-        time += 0.01;
+        time += 0.015;
     }
 
     return 0;