多重采样

Material.cpp

@@ -0,0 +1,10 @@
+#include "Material.h"
+#include "Ray.h"
+#include <math.h>
+bool LamberMaterial::Scatter(const Ray & input_ray, const HitPoint & hit_point, Ray & out_ray)
+{
+	Vector3 random_vector = UnitRandomVector3InSphere();
+	Vector3 new_direction = hit_point.mNormal + random_vector;
+	out_ray.Set(hit_point.mPosition, new_direction, input_ray.mLightAttenuation*mDiffuse);
+	return true;
+}

Material.h

@@ -0,0 +1,13 @@
+#pragma once
+#include "Vector3.h"
+class Ray;
+class Material {
+public:
+	virtual bool Scatter(const Ray& input_ray, const HitPoint& hit_point, Ray& out_ray) = 0;
+};
+class LamberMaterial : public Material {
+public:
+	Vector3 mDiffuse;
+	LamberMaterial(const Vector3 diffuse) { mDiffuse = diffuse; }
+	bool Scatter(const Ray& input_ray, const HitPoint& hit_point, Ray& out_ray);
+};

Object.cpp

@@ -0,0 +1,25 @@
+#include "Object.h"
+#include "Material.h"
+#include "Ray.h"
+#include <math.h>
+
+Object::Object(Geometry * g, Material * m)
+{
+	mGeometry = g;
+	mMaterial = m;
+}
+
+void Object::Set(Geometry * g, Material * m)
+{
+	mGeometry = g;
+	mMaterial = m;
+}
+
+bool Object::HitTest(const Ray & input_ray, float min_distance, float max_distance, HitPoint & hit_point)
+{
+	if (mGeometry->HitTest(input_ray, min_distance, max_distance, hit_point)) {
+		hit_point.mMaterial = mMaterial;
+		return true;
+	}
+	return false;
+}

Object.h

@@ -0,0 +1,11 @@
+#pragma once
+#include "Vector3.h"
+class Material;
+class Object {
+public:
+	Geometry *mGeometry;
+	Material *mMaterial;
+	Object(Geometry* g, Material* m);
+	void Set(Geometry* g, Material* m);
+	bool HitTest(const Ray& input_ray, float min_distance, float max_distance, HitPoint& hit_point);
+};

Ray.h

@@ -3,6 +3,7 @@
 class Ray {
 public:
 	Vector3 mOrigin, mDirection, mLightAttenuation;
+	Ray() {};
 	Ray(const Vector3& origin, const Vector3& direction, const Vector3& attenuation);
 	void Set(const Vector3& origin, const Vector3& direction, const Vector3& attenuation);
 	Vector3 PointAt(float k) const;

Scene.cpp

@@ -2,6 +2,8 @@
 #include "util.h"
 #include "Camera.h"
 #include "Ray.h"
+#include "Material.h"
+#include "Object.h"
 #include "Vector3.h"
 #include "Sphere.h"
 #pragma comment(lib, "winmm.lib")
@@ -9,6 +11,17 @@ static int sTotalPixelCount = 0;
 static int sViewportWidth = 0, sViewportHeight = 0;
 static Camera* sCamera = nullptr;
 Sphere sphere(Vector3(0.0f, 0.0f, -5.0f), 0.5f);
+static Object* sRootObject = nullptr;
+static Material* lambert = nullptr;
+static int sSampleCount = 64;
+void AddObject(Object* object) {
+	if (sRootObject == nullptr) {
+		sRootObject = object;
+	}
+	else {
+		//TODO
+	}
+}
 void Init(int width, int height)
 {
 	sTotalPixelCount = width * height;
@@ -16,6 +29,8 @@ void Init(int width, int height)
 	sViewportHeight = height;
 	sCamera = new Camera(45.0f, float(width) / float(height));
 	sCamera->LookAt(Vector3(0.0f, 0.0f, 0.0f), Vector3(0.0f, 0.0f, -1.0f), Vector3(0.0f, 1.0f, 0.0f));
+	lambert = new LamberMaterial(Vector3(0.1f, 0.4f, 0.7f));
+	AddObject(new Object(&sphere, lambert));
 }
 
 float GetEscaptedTime() {
@@ -35,29 +50,37 @@ Vector3 GetEnviromentColor(const Ray& input_ray) {
 	return factor * top_color + (1.0f - factor) * bottom_color;
 }
 
+Vector3 GetColor(const Ray& input_ray) {
+	HitPoint hit_point;
+	if (sRootObject->HitTest(input_ray, 0.01f, 100.0f, hit_point)) {
+		Ray scatter_ray;
+		if (hit_point.mMaterial->Scatter(input_ray, hit_point, scatter_ray)) {
+			return GetColor(scatter_ray);
+		}
+	}
+
+	return GetEnviromentColor(input_ray);
+}
+
 void RenderOnePixel(int pixel_index) {
 	int x = pixel_index % sViewportWidth;
 	int y = pixel_index / sViewportWidth;
-	float u = float(x) / sViewportWidth;
-	float v = float(y) / sViewportHeight;
-	Ray ray = sCamera->GetRay(u,v);
-	HitPoint hit_point;
-	if (sphere.HitTest(ray, 0.0f, 100.0f, hit_point)) {
-		float rf = hit_point.mNormal.x * 0.5f + 0.5f;
-		float gf = hit_point.mNormal.y * 0.5f + 0.5f;
-		float bf = hit_point.mNormal.z * 0.5f + 0.5f;
-		AByte r = AByte(rf * 255.0f);
-		AByte g = AByte(gf * 255.0f);
-		AByte b = AByte(bf * 255.0f);
-		SetColor(x, y, r, g, b, 255);
+
+	Vector3 color;
+	for (int i = 0; i < sSampleCount; i++) {
+		float offset_u = srandf()*0.5;
+		float offset_v = srandf()*0.5;
+		float u = (float(x) + offset_u) / sViewportWidth;
+		float v = (float(y) + offset_v) / sViewportHeight;
+		Ray ray = sCamera->GetRay(u, v);
+		Vector3 current_color = GetColor(ray);
+		color = color + current_color;
 	}
-	else {
-		Vector3 color = GetEnviromentColor(ray);
+	color /= sSampleCount;
 	AByte r = AByte(color.x * 255.0f);
 	AByte g = AByte(color.y * 255.0f);
 	AByte b = AByte(color.z * 255.0f);
 	SetColor(x, y, r, g, b, 255);
-	}
 }
 
 void Render()
@@ -67,7 +90,7 @@ void Render()
 	while (sCurrentRenderPixel < sTotalPixelCount) {
 		RenderOnePixel(sCurrentRenderPixel);
 		sCurrentRenderPixel++;
-		current_render_time = GetEscaptedTime();
+		current_render_time += GetEscaptedTime();
 		if (current_render_time > 0.016f) {
 			break;
 		}

Vector3.cpp

@@ -1,5 +1,6 @@
 #include "Vector3.h"
 #include <math.h>
+#include "util.h"
 
 Vector3 Vector3::operator+(const Vector3 & v) const
 {
@@ -69,3 +70,10 @@ Vector3 Cross(const Vector3 & l, const Vector3 & r)
 {
 	return Vector3(l.y*r.z - l.z*r.y, l.z*r.x - l.x*r.z, l.x*r.y - l.y*r.x);
 }
+
+Vector3 UnitRandomVector3InSphere()
+{
+	Vector3 random_vector(srandf(), srandf(), srandf());
+	random_vector.Normalize();
+	return random_vector;
+}

Vector3.h

@@ -47,5 +47,7 @@ struct HitPoint {
 };
 class Ray;
 class Geometry {
+public:
 	virtual bool HitTest(const Ray& input_ray, float min_distance, float max_distance, HitPoint& hit_point) = 0;
 };
+Vector3 UnitRandomVector3InSphere();

raytracing.vcxproj

@@ -128,6 +128,8 @@
   <ItemGroup>
     <ClCompile Include="Camera.cpp" />
     <ClCompile Include="main.cpp" />
+    <ClCompile Include="Material.cpp" />
+    <ClCompile Include="Object.cpp" />
     <ClCompile Include="Ray.cpp" />
     <ClCompile Include="Scene.cpp" />
     <ClCompile Include="Sphere.cpp" />
@@ -136,6 +138,8 @@
   </ItemGroup>
   <ItemGroup>
     <ClInclude Include="Camera.h" />
+    <ClInclude Include="Material.h" />
+    <ClInclude Include="Object.h" />
     <ClInclude Include="Ray.h" />
     <ClInclude Include="Scene.h" />
     <ClInclude Include="Sphere.h" />

raytracing.vcxproj.filters

@@ -36,6 +36,12 @@
     <ClCompile Include="Sphere.cpp">
       <Filter>源文件</Filter>
     </ClCompile>
+    <ClCompile Include="Object.cpp">
+      <Filter>源文件</Filter>
+    </ClCompile>
+    <ClCompile Include="Material.cpp">
+      <Filter>源文件</Filter>
+    </ClCompile>
   </ItemGroup>
   <ItemGroup>
     <ClInclude Include="Scene.h">
@@ -56,5 +62,11 @@
     <ClInclude Include="Sphere.h">
       <Filter>源文件</Filter>
     </ClInclude>
+    <ClInclude Include="Object.h">
+      <Filter>源文件</Filter>
+    </ClInclude>
+    <ClInclude Include="Material.h">
+      <Filter>源文件</Filter>
+    </ClInclude>
   </ItemGroup>
 </Project>

util.cpp

@@ -31,3 +31,13 @@ void ASwapBuffers(HDC dc)
 {
 	BitBlt(dc, 0, 0, sRenderableBuffer->mWidth, sRenderableBuffer->mHeight, sRenderableBuffer->mDC, 0,0, SRCCOPY);
 }
+
+float randf()
+{
+	return float(rand()) / float(RAND_MAX);
+}
+
+float srandf()
+{
+	return randf() * 2.0f - 1.0f;
+}

util.h

@@ -16,3 +16,5 @@ struct RenderableBuffer {
 void InitRenderableBuffer(HDC dc, int width, int height);
 void SetColor(int x, int y, AByte r, AByte g, AByte b, AByte a);
 void ASwapBuffers(HDC dc);
+float randf();
+float srandf();