From 9e8028f90431b9e66ae21af595ead91e5f03c2db Mon Sep 17 00:00:00 2001
From: Crizomb <clementbart.45@gmail.com>
Date: Fri, 26 Sep 2025 21:43:08 +0200
Subject: [PATCH] Phong shading

---
 material.go     |  7 +++++--
 ray_marching.go | 20 +++++++++++++++++++-
 2 files changed, 24 insertions(+), 3 deletions(-)

diff --git a/material.go b/material.go
index 966fc07..d9e7837 100644
--- a/material.go
+++ b/material.go
@@ -6,6 +6,7 @@ type Color interface {
 
 // Ambre je te copie
 type Material struct {
+	ambiantColor    Color
 	diffuseColor    Color
 	diffuseFac      float64
 	specularColor   Color
@@ -17,9 +18,10 @@ type Material struct {
 	refractIndice   float64
 }
 
-func DefaultMaterial(diffuseColor Color) Material {
+func DefaultMaterial(ambiantColor Color) Material {
 	return Material{
-		diffuseColor:    diffuseColor,
+		ambiantColor:    ambiantColor,
+		diffuseColor:    Vector3{255, 255, 255},
 		diffuseFac:      1.0,
 		specularColor:   Vector3{1.0, 1.0, 1.0},
 		specularFac:     0.5,
@@ -33,6 +35,7 @@ func DefaultMaterial(diffuseColor Color) Material {
 
 func MixMat(mat1 Material, mat2 Material, t float64, p Vector3) Material {
 	return Material{
+		mat1.ambiantColor.GetColor(p).Scale(1 - t).Add((mat2.ambiantColor.GetColor(p)).Scale(t)),
 		mat1.diffuseColor.GetColor(p).Scale(1 - t).Add((mat2.diffuseColor.GetColor(p)).Scale(t)),
 		(mat1.diffuseFac*(1-t) + mat2.diffuseFac) * t,
 		mat1.specularColor.GetColor(p).Scale(1 - t).Add((mat2.specularColor.GetColor(p)).Scale(t)),
diff --git a/ray_marching.go b/ray_marching.go
index 888a5ec..551d67f 100644
--- a/ray_marching.go
+++ b/ray_marching.go
@@ -17,6 +17,7 @@ const WIDTH = 500
 const HEIGHT = 500
 const PI = math.Pi
 
+var lightPos Vector3 = Vector3{0, 200, 400}
 var sphere Sphere = Sphere{Vector3{0, 100, 10}, 10, RED_MAT}
 var plane Plane = Plane{Vector3{0, 0, 1}, -10, GREY_MAT}
 var scene UnionSDF = UnionSDF{sphere, plane}
@@ -27,6 +28,22 @@ var cameraPos Vector3 = Vector3{0, -10, 0}
 var screenSpherical Vector3 = Vector3{10, PI / 2, PI / 2}
 var screenPhysicalSize float64 = 5
 
+func phongShading(point Vector3, normal Vector3, mat Material) Vector3 {
+	lightVec := (lightPos.Sub(point)).Normalized()
+	reflectLight := Reflect(lightVec, normal)
+	eyeVec := (cameraPos.Sub(point)).Normalized()
+
+	ambiant := mat.ambiantColor.GetColor(point).Scale(0.1)
+
+	diffusePower := mat.diffuseFac * max(0, normal.Dot(lightVec)) * 0.5
+	diffuse := mat.diffuseColor.GetColor(point).Scale(diffusePower)
+
+	specularPower := mat.specularFac * math.Pow(max(0, reflectLight.Dot(eyeVec)), mat.specularExp)
+	specular := mat.specularColor.GetColor(point).Scale(specularPower)
+
+	return ambiant.Add(diffuse).Add(specular)
+}
+
 func rayMarch(origin Vector3, direction Vector3) (bool, Vector3) {
 	p := origin
 	for range MAX_STEP {
@@ -34,7 +51,8 @@ func rayMarch(origin Vector3, direction Vector3) (bool, Vector3) {
 		// fmt.Println(dist)
 		if dist < EPS {
 			// fmt.Println("hit")
-			return true, mat.diffuseColor.GetColor(p)
+			normal := Gradient(scene, p, EPS).Normalized()
+			return true, phongShading(p, normal, mat)
 		}
 		if dist > MAX_DIST {
 			break