Add specular lighting

include/light.h

@@ -1,6 +1,7 @@
 #ifndef LIGHT_H
 
 
+#include "camera.h"
 #include "color.h"
 #include "geometry.h"
 #include "point.h"
@@ -18,7 +19,7 @@ struct Light
 
 
 // PUBLIC FUNCTIONS
-ColorF32 ComputeLight(Vertex &vert, Material &material, Light &light);
+ColorF32 ComputeLight(Vertex &vert, Material &material, Light &light, Camera &camera);
 
 
 #define LIGHT_H

include/vec.h

@@ -32,6 +32,18 @@ inline Vector operator-(Vector const &v)
     return result;
 }
 
+// v1 - v2
+inline Vector operator-(Vector const &v1, Vector const &v2)
+{
+    Vector result;
+
+    result.x = v1.x - v2.x;
+    result.y = v1.y - v2.y;
+    result.z = v1.z - v2.z;
+
+    return result;
+}
+
 // v1 + v2
 inline Vector operator+(Vector const &v1, Vector const &v2)
 {

src/engine.cpp

@@ -64,8 +64,8 @@ int EngineInit(char *objFilename, char *mtlFilename)
 
 
     // Mesh configuration
-    mesh.position.z = 125;
-    mesh.position.y = -125;
+    mesh.position.z = 175;
+    mesh.position.y = -175;
     mesh.scale = 1.0f;
 
 
@@ -152,29 +152,29 @@ static void CheckInputs(uint32_t input)
 
     if (CHECK_BIT(input, ROTATE_X_POS))
     {
-        mesh.rotation.x += .10;
+        mesh.position.x += 10;
     }
     else if (CHECK_BIT(input, ROTATE_X_NEG))
     {
-        mesh.rotation.x -= .10;
+        mesh.position.x -= 10;
     }
 
     if (CHECK_BIT(input, ROTATE_Y_POS))
     {
-        mesh.rotation.y += .10;
+        mesh.position.y += 10;
     }
     else if (CHECK_BIT(input, ROTATE_Y_NEG))
     {
-        mesh.rotation.y -= .10;
+        mesh.position.y -= 10;
     }
 
     if (CHECK_BIT(input, ROTATE_Z_POS))
     {
-        mesh.rotation.z += .10;
+        mesh.position.z += 10;
     }
     else if (CHECK_BIT(input, ROTATE_Z_NEG))
     {
-        mesh.rotation.z -= .10;
+        mesh.position.z -= 10;
     }
 
     if (CHECK_BIT(input, SCALE_UP))
@@ -338,7 +338,7 @@ static void LightMesh(void)
         {
             Vertex &vert = verts.data[face.vertIndex[i]];
 
-            vert.color = ComputeLight(vert, material, light);
+            vert.color = ComputeLight(vert, material, light, camera);
         }
     }
 }

src/light.cpp

@@ -1,45 +1,49 @@
+#include "camera.h"
 #include "color.h"
 #include "light.h"
 
 
 // PRIVATE PROTOTYPES
 static ColorF32 ComputeAmbientLight(
-        ColorF32 surfaceReflectivity, ColorF32 lightIntensity);
+        Material &material, ColorF32 &intensity);
 
 static ColorF32 ComputeDiffuseLight(
-        ColorF32 surfaceReflectivity, ColorF32 lightIntensity,
-        Point &vertPosition, Vector &vertNormal,
-        Point &lightPosition);
+        Material &material, ColorF32 &intensity, Vertex &vert, Light &light);
+
+static ColorF32 ComputeSpecularLight(
+        Material &material, ColorF32 &intensity, Vertex &vert, Light &light,
+        Camera &camera);
 
 
 // PUBLIC FUNCTIONS
-ColorF32 ComputeLight(Vertex &vert, Material &material, Light &light)
+ColorF32 ComputeLight(
+        Vertex &vert, Material &material, Light &light, Camera &camera)
 {
     // Distance from light to vertex
     Vector direction = light.position - vert.point;
     float distance = VectorLength(direction);
 
 
-    // Intensity is a function of the falloff factors and the distance
+    // Point light intensity is a function of the falloff factors and the distance
     ColorF32 intensity =
         (light.intensity * light.color)
         / (light.falloffConstant + light.falloffLinear * distance);
 
 
     // Compute ambient light
-    ColorF32 ambientLight = ComputeAmbientLight(
-            material.ambient, intensity);
+    ColorF32 ambientLight = ComputeAmbientLight(material, intensity);
 
 
     // Compute diffuse light
-    ColorF32 diffuseLight = ComputeDiffuseLight(
-            material.diffuse, intensity,
-            vert.point, vert.normal,
-            light.position);
+    ColorF32 diffuseLight = ComputeDiffuseLight(material, intensity, vert, light);
+
+
+    // Compute specular light
+    ColorF32 specularLight = ComputeSpecularLight(material, intensity, vert, light, camera);
 
 
     // Total light is sum of all lights
-    ColorF32 result = ambientLight + diffuseLight;
+    ColorF32 result = ambientLight + diffuseLight + specularLight;
 
 
     return result;
@@ -48,29 +52,55 @@ ColorF32 ComputeLight(Vertex &vert, Material &material, Light &light)
 
 // PRIVATE FUNCTIONS
 static ColorF32 ComputeAmbientLight(
-        ColorF32 surfaceReflectivity, ColorF32 lightIntensity)
+        Material &material, ColorF32 &intensity)
 {
-    ColorF32 result;
-
-
-    result = surfaceReflectivity * lightIntensity;
+    // light = Kd * I
+    ColorF32 result = material.ambient * intensity;
 
 
     return result;
 }
 
 static ColorF32 ComputeDiffuseLight(
-        ColorF32 surfaceReflectivity, ColorF32 lightIntensity,
-        Point &vertPosition, Vector &vertNormal,
-        Point &lightPosition)
+        Material &material, ColorF32 &intensity, Vertex &vert, Light &light)
 {
-    // Light is a function of the position of the light source and the surface
-    Vector direction = lightPosition - vertPosition;
+    // Vector from the light to the vertex
+    Vector direction = light.position - vert.point;
     VectorNormalize(direction);
+    float normalDotDirection = VectorDot(vert.normal, direction);
 
-    float dot = VectorDot(vertNormal, direction);
 
-    ColorF32 result = surfaceReflectivity * lightIntensity * dot;
+    // light = Kr * I * n.d
+    ColorF32 result = material.diffuse * intensity * normalDotDirection;
+
+
+    return result;
+}
+
+static ColorF32 ComputeSpecularLight(
+        Material &material, ColorF32 &intensity, Vertex &vert, Light &light,
+        Camera &camera)
+{
+    // Vector from the camera to the vertex
+    Vector view = camera.position - vert.point;
+    VectorNormalize(view);
+
+
+    // Vector from the light to the vertex
+    Vector direction = light.position - vert.point;
+    VectorNormalize(direction);
+
+
+    // Reflection vector of the light vector across the vertex normal
+    float normalDotDirection = VectorDot(vert.normal, direction);
+    Vector reflection = (2.0f * normalDotDirection * vert.normal) - direction;
+    float reflectDotView = MAX(VectorDot(reflection, view), 0.0f);
+
+
+    // light = Ks * I * (r.v)^sp
+    ColorF32 result =
+        material.specular * intensity * powf(reflectDotView, material.specularExp);
+
 
     return result;
 }