Modify lighting equations

include/geometry.h

@@ -31,7 +31,7 @@ struct Material
     ColorF32 ambient;
     ColorF32 diffuse;
     ColorF32 specular;
-    float specularExp;
+    float glossiness;
     float opacity;
 };
 

include/light.h

@@ -19,7 +19,7 @@ struct Light
 
 
 // PUBLIC FUNCTIONS
-ColorF32 ComputeLight(Vertex &vert, Material &material, Light &light, Camera &camera);
+ColorF32 ComputeLight(Point &position, Vector &normal, Material &material, Light &light, Camera &camera);
 
 
 #define LIGHT_H

src/engine.cpp

@@ -70,7 +70,7 @@ int EngineInit(char *objFilename, char *mtlFilename)
 
 
     // Light configuration
-    light.position = Point(-100.0f, 200.0f, 0.0f);
+    light.position = Point(-300.0f, 200.0f, 0.0f);
     light.color = {1.0f, 1.0f, 1.0f, 1.0f};
     light.intensity = 2.0f;
     light.falloffConstant = 1.0f;
@@ -338,7 +338,7 @@ static void LightMesh(void)
         {
             Vertex &vert = verts.data[face.vertIndex[i]];
 
-            vert.color = ComputeLight(vert, material, light, camera);
+            vert.color = ComputeLight(vert.position, vert.normal, material, light, camera);
         }
     }
 }

src/light.cpp

@@ -3,103 +3,44 @@
 #include "light.h"
 
 
-// PRIVATE PROTOTYPES
-static ColorF32 ComputeAmbientLight(
-        Material &material, ColorF32 &intensity);
-
-static ColorF32 ComputeDiffuseLight(
-        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, Camera &camera)
+        Point &position, Vector &normal, Material &material, Light &light, Camera &camera)
 {
-    // Distance from light to vertex
-    Vector direction = light.position - vert.position;
+    // Point light intensity is a function of the falloff factors and the distance
+    Vector direction = light.position - position;
+    VectorNormalize(direction);
     float distance = VectorLength(direction);
 
-
-    // Point light intensity is a function of the falloff factors and the distance
     ColorF32 intensity =
         (light.intensity * light.color)
-        / (light.falloffConstant + light.falloffLinear * distance);
+        / (light.falloffConstant + (light.falloffLinear * distance));
 
 
-    // Compute ambient light
-    ColorF32 ambientLight = ComputeAmbientLight(material, intensity);
+    // Diffuse Light = Kr * I * (alpha + (1 - alpha) * n.d)
+    float dotNormalDirection = MAX(VectorDot(normal, direction), 0.0f);
+    float alpha = 0.2f;
+
+    ColorF32 diffuseLight =
+        material.diffuse
+        * intensity
+        * (alpha + (1.0f - alpha) * dotNormalDirection);
 
 
-    // Compute diffuse light
-    ColorF32 diffuseLight = ComputeDiffuseLight(material, intensity, vert, light);
+    // Specular Light = Ks * I * (r.v)^sp
+    Vector view = camera.position - position;
+    VectorNormalize(view);
+    Vector reflection = (2.0f * dotNormalDirection * normal) - direction;
+    float dotReflectionView = MAX(VectorDot(reflection, view), 0.0f);
 
-
-    // Compute specular light
-    ColorF32 specularLight = ComputeSpecularLight(material, intensity, vert, light, camera);
+    ColorF32 specularLight =
+        material.specular
+        * intensity
+        * powf(dotReflectionView, material.glossiness);
 
 
     // Total light is sum of all lights
-    ColorF32 result = ambientLight + diffuseLight + specularLight;
-
-
-    return result;
-}
-
-
-// PRIVATE FUNCTIONS
-static ColorF32 ComputeAmbientLight(
-        Material &material, ColorF32 &intensity)
-{
-    // light = Kd * I
-    ColorF32 result = material.ambient * intensity;
-
-
-    return result;
-}
-
-static ColorF32 ComputeDiffuseLight(
-        Material &material, ColorF32 &intensity, Vertex &vert, Light &light)
-{
-    // Vector from the light to the vertex
-    Vector direction = light.position - vert.position;
-    VectorNormalize(direction);
-    float normalDotDirection = VectorDot(vert.normal, direction);
-
-
-    // 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.position;
-    VectorNormalize(view);
-
-
-    // Vector from the light to the vertex
-    Vector direction = light.position - vert.position;
-    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);
+    ColorF32 result = diffuseLight + specularLight;
 
 
     return result;

src/loader.cpp

@@ -157,7 +157,7 @@ int ParseMTL(char *filename, EngineMemory &memory)
             else if (strcmp(type, "Ns") == 0)
             {
                 sscanf( data, "%f",
-                        &materials.data[materialIndex].specularExp);
+                        &materials.data[materialIndex].glossiness);
             }
 
             else if (strcmp(type, "Ka") == 0)