From 80fed125b45852edd93395d3fa1b64574b77f489 Mon Sep 17 00:00:00 2001
From: Fabien Freling <public@ffreling.com>
Date: Tue, 27 Apr 2021 08:30:24 +0200
Subject: [PATCH] display progress bar

---
 in_one_weekend/src/main.zig | 95 +++++++++++++++++++++++--------------
 1 file changed, 60 insertions(+), 35 deletions(-)

diff --git a/in_one_weekend/src/main.zig b/in_one_weekend/src/main.zig
index abec5c8..7c145ab 100644
--- a/in_one_weekend/src/main.zig
+++ b/in_one_weekend/src/main.zig
@@ -44,6 +44,26 @@ fn rayColor(ray: Ray, world: World) Color {
     return white.mul(1.0 - t).add(blue.mul(t));
 }
 
+fn setProgress(surface: *sdl.c.SDL_Surface, width: usize, height: usize, percent: f32) void {
+    if (percent == 1.0) {
+        return;
+    }
+    
+    const progressBarHeight = 3;
+    const progressWidth = @floatToInt(usize, @intToFloat(f32, width) * percent);
+    const progressColor = Color{ .x = 1.0 };
+
+    var j: usize = 0;
+    while (j < progressBarHeight) {
+        var i: usize = 0;
+        while (i < progressWidth) {
+            sdl.setSurfacePixel(surface, i, j, progressColor);
+            i += 1;
+        }
+        j += 1;
+    }
+}
+
 pub fn main() anyerror!void {
     if (sdl.c.SDL_Init(sdl.c.SDL_INIT_VIDEO) != 0) {
         std.log.err("Unable to initialize SDL: {}", .{sdl.c.SDL_GetError()});
@@ -90,46 +110,13 @@ pub fn main() anyerror!void {
         pixel.* = Color{};
     }
 
-    {
-        _ = sdl.c.SDL_LockSurface(surface);
-
-        var k: usize = 0;
-        while (k < samplesPerPixel) {
-            _ = sdl.c.SDL_LockSurface(surface);
-
-            var j: usize = 0;
-            while (j < imageHeight) {
-                var i: usize = 0;
-                while (i < imageWidth) {
-                    var imageIndex = i + j * imageWidth;
-                    var pixelColor = &pixelAccu[imageIndex];
-
-                    const u = (@intToFloat(f32, i) + prng.random.float(f32)) / @intToFloat(f32, (imageWidth - 1));
-                    const v = (@intToFloat(f32, j) + prng.random.float(f32)) / @intToFloat(f32, (imageHeight - 1));
-                    const r = camera.getRay(u, v);
-                    const sample = rayColor(r, world);
-                    pixelColor.* = pixelColor.*.add(sample);
-
-                    const averageColor = color.averageColor(pixelColor, @intCast(i32, k));
-                    // SDL coordinate system is flipped compared to the raytracer
-                    sdl.setSurfacePixel(surface, i, imageHeight - 1 - j, averageColor);
-
-                    i += 1;
-                }
-                j += 1;
-            }
-            sdl.c.SDL_UnlockSurface(surface);
-            _ = sdl.c.SDL_UpdateWindowSurface(window);
-            k += 1;
-        }
-    }
-
     if (sdl.c.SDL_UpdateWindowSurface(window) != 0) {
         std.log.err("Error updating window surface: {}", .{sdl.c.SDL_GetError()});
         return error.SDLUpdateWindowFailed;
     }
 
     var running = true;
+    var k: usize = 0;
     while (running) {
         var event: sdl.c.SDL_Event = undefined;
         while (sdl.c.SDL_PollEvent(&event) != 0) {
@@ -140,6 +127,44 @@ pub fn main() anyerror!void {
                 else => {},
             }
         }
-        sdl.c.SDL_Delay(1000 / fps);
+
+        // Render
+        {
+            while (k < samplesPerPixel) {
+                _ = sdl.c.SDL_LockSurface(surface);
+
+                var j: usize = 0;
+                while (j < imageHeight) {
+                    var i: usize = 0;
+                    while (i < imageWidth) {
+                        var imageIndex = i + j * imageWidth;
+                        var pixelColor = &pixelAccu[imageIndex];
+
+                        const u = (@intToFloat(f32, i) + prng.random.float(f32)) / @intToFloat(f32, (imageWidth - 1));
+                        const v = (@intToFloat(f32, j) + prng.random.float(f32)) / @intToFloat(f32, (imageHeight - 1));
+                        const r = camera.getRay(u, v);
+                        const sample = rayColor(r, world);
+                        pixelColor.* = pixelColor.*.add(sample);
+
+                        const averageColor = color.averageColor(pixelColor, @intCast(i32, k));
+                        // SDL coordinate system is flipped compared to the raytracer
+                        sdl.setSurfacePixel(surface, i, imageHeight - 1 - j, averageColor);
+
+                        i += 1;
+                    }
+                    j += 1;
+                }
+
+                setProgress(surface, imageWidth, imageHeight, @intToFloat(f32, k + 1) / @intToFloat(f32, samplesPerPixel));
+
+                sdl.c.SDL_UnlockSurface(surface);
+                _ = sdl.c.SDL_UpdateWindowSurface(window);
+                k += 1;
+            }
+        }
+
+        if (k >= samplesPerPixel) {
+            sdl.c.SDL_Delay(1000 / fps);
+        }
     }
 }