From f429c80bbfed5857f1aacf79748dfeb3f8927521 Mon Sep 17 00:00:00 2001
From: Mark McArdle <mark.mcardle@sohonet.com>
Date: Wed, 7 Oct 2020 18:56:22 +0100
Subject: [PATCH] Add multiprocessing renderer

---
 pyrt/renderer/__init__.py |  1 +
 pyrt/renderer/mprt.py     | 90 +++++++++++++++++++++++++++++++++++++++
 2 files changed, 91 insertions(+)
 create mode 100644 pyrt/renderer/mprt.py

diff --git a/pyrt/renderer/__init__.py b/pyrt/renderer/__init__.py
index 6fbfd9d..a7e2fdd 100644
--- a/pyrt/renderer/__init__.py
+++ b/pyrt/renderer/__init__.py
@@ -6,4 +6,5 @@
 
 from .renderer import Renderer
 from .simplert import SimpleRT
+from .mprt import MultiProcessRT
 from .rgbimage import RGBImage, loadimage
diff --git a/pyrt/renderer/mprt.py b/pyrt/renderer/mprt.py
new file mode 100644
index 0000000..c072aa2
--- /dev/null
+++ b/pyrt/renderer/mprt.py
@@ -0,0 +1,90 @@
+"""
+A multi processing ray tracer
+"""
+
+from .rgbimage import *
+from .renderer import Renderer
+from ..scene import Scene
+from ..math import *
+
+from .simplert import SimpleRT
+
+from multiprocessing import Pool
+import time
+
+
+class MultiProcessRT(SimpleRT):
+
+    def __init__(self, shadow=False, iterations=1):
+        Renderer.__init__(self, "MP Raytracer")
+        self.shadow = shadow
+        self.iterations = iterations
+        if self.shadow:
+            print("# Shadow Enabled")
+        if self.iterations>1:
+            print("# Iterations: " + str(self.iterations))
+
+
+    def trace_ray_multiprocess(engine, scene, x, y):
+        ray = scene.camera.primaryRay(x, y)
+        hitrecord = HitRecord()
+        engine.num_rays += 1
+
+        # Reset shadow rays for the process
+        engine.num_shadow_rays = 0
+      
+        num_secondary_rays = 0
+
+        # Primary Ray:
+        hit, r, g, b = engine._shade(scene, ray, hitrecord)
+
+        if hit and hitrecord.material.reflectivity != 0.0:
+            refhit = hitrecord.copy()
+            refray = ray.copy()
+            for i in range(engine.iterations - 1):
+                r, g, b, refray, refhit = engine._reflect(r,g,b, scene, refray, refhit)
+                num_secondary_rays += 1
+                if refray is None:
+                    break
+
+        return x, y, r, g, b, num_secondary_rays, engine.num_shadow_rays
+
+    def render(self, scene: Scene) -> RGBImage:
+        if not scene.camera:
+            print("Warning: Can't render: there is no (active) camera in the scene!")
+            return None
+
+        time_start = time.time()
+        self.num_shadow_rays = 0
+        self.num_secondary_rays = 0
+
+        w = scene.camera.width
+        h = scene.camera.height
+
+        self.num_rays = w * h
+
+        image = RGBImage(w,h)
+        
+        args = []
+        for y in range(0, h):
+            for x in range(0, w):
+                args.append([scene, x, y])
+
+        with Pool() as p:
+            for result in p.starmap(self.trace_ray_multiprocess, args):
+                x, y, r, g, b, secondary_rays, shadow_rays = result
+                image.drawPixelFast8(x, y, r, g, b)
+                self.num_secondary_rays += secondary_rays
+                self.num_shadow_rays += shadow_rays
+
+        time_end = time.time()
+        print("# RENDER STATISTICS" + 31 * "#")
+        time_total = time_end - time_start
+        print("TIME FOR RENDERING: " + str(time_total) + "s")
+        print("NUMBER OF PRIMARY RAYS: " + str(self.num_rays))
+        print("NUMBER OF SECONDARY RAYS: " + str(self.num_secondary_rays))
+        print("NUMBER OF SHADOW RAYS: " + str(self.num_shadow_rays))
+        print("RAYS/s: " + str((self.num_rays + self.num_secondary_rays + self.num_shadow_rays) / time_total))
+        print(50 * "#")
+
+        return image