From db0d39d487428df505386dee55e26cba0997e876 Mon Sep 17 00:00:00 2001
From: Luke Benstead <kazade@gmail.com>
Date: Sat, 4 Aug 2018 19:34:07 +0100
Subject: [PATCH] Cleanup lighting code a bit

---
 GL/lighting.c | 36 ++++++++++++++++++++++++------------
 GL/private.h  |  1 +
 2 files changed, 25 insertions(+), 12 deletions(-)

diff --git a/GL/lighting.c b/GL/lighting.c
index 3a9aa9a..75509b8 100644
--- a/GL/lighting.c
+++ b/GL/lighting.c
@@ -47,6 +47,8 @@ void initLights() {
         LIGHTS[i].constant_attenuation = 1.0f;
         LIGHTS[i].linear_attenuation = 0.0f;
         LIGHTS[i].quadratic_attenuation = 0.0f;
+
+        LIGHTS[i].is_directional = GL_FALSE;
     }
 }
 
@@ -109,6 +111,8 @@ void APIENTRY glLightfv(GLenum light, GLenum pname, const GLfloat *params) {
             _matrixLoadModelView();
             memcpy(LIGHTS[idx].position, params, sizeof(GLfloat) * 4);
 
+            LIGHTS[idx].is_directional = (params[3] == 0.0f) ? GL_TRUE : GL_FALSE;
+
             mat_trans_single4(
                 LIGHTS[idx].position[0],
                 LIGHTS[idx].position[1],
@@ -269,26 +273,34 @@ void calculateLightingContribution(const GLint light, const GLfloat* pos, const
 
     vec3f_normalize(V.x, V.y, V.z);
 
-    GLfloat NdotL;
+    GLfloat NdotL, VdotN;
     vec3f_dot(N.x, N.y, N.z, L.x, L.y, L.z, NdotL);
-
-    GLfloat f = (NdotL < 0) ? 0 : 1;
-
-    GLfloat VdotN;
     vec3f_dot(V.x, V.y, V.z, N.x, N.y, N.z, VdotN);
 
     GLfloat VdotR = VdotN - NdotL;
     GLfloat specularPower = FPOW(VdotR > 0 ? VdotR : 0, MATERIAL.exponent);
 
-    GLfloat att = (l->position[3] == 0.0f) ? 1.0f : (
-        1.0f / (l->constant_attenuation + (l->linear_attenuation * d) + (l->quadratic_attenuation * d * d))
-    );
-
-    colour[0] = att * (l->ambient[0] * MATERIAL.ambient[0] + f * (l->diffuse[0] * MATERIAL.diffuse[0] * NdotL + l->specular[0] * MATERIAL.specular[0] * specularPower));
-    colour[1] = att * (l->ambient[1] * MATERIAL.ambient[1] + f * (l->diffuse[1] * MATERIAL.diffuse[1] * NdotL + l->specular[1] * MATERIAL.specular[1] * specularPower));
-    colour[2] = att * (l->ambient[2] * MATERIAL.ambient[2] + f * (l->diffuse[2] * MATERIAL.diffuse[2] * NdotL + l->specular[2] * MATERIAL.specular[2] * specularPower));
+    colour[0] = l->ambient[0] * MATERIAL.ambient[0];
+    colour[1] = l->ambient[1] * MATERIAL.ambient[1];
+    colour[2] = l->ambient[2] * MATERIAL.ambient[2];
     colour[3] = MATERIAL.diffuse[3];
 
+    if(NdotL >= 0) {
+        colour[0] += (l->diffuse[0] * MATERIAL.diffuse[0] * NdotL + l->specular[0] * MATERIAL.specular[0] * specularPower);
+        colour[1] += (l->diffuse[1] * MATERIAL.diffuse[1] * NdotL + l->specular[1] * MATERIAL.specular[1] * specularPower);
+        colour[2] += (l->diffuse[2] * MATERIAL.diffuse[2] * NdotL + l->specular[2] * MATERIAL.specular[2] * specularPower);
+    }
+
+    if(!l->is_directional) {
+        GLfloat att = (
+            1.0f / (l->constant_attenuation + (l->linear_attenuation * d) + (l->quadratic_attenuation * d * d))
+        );
+
+        colour[0] *= att;
+        colour[1] *= att;
+        colour[2] *= att;
+    }
+
     if(colour[0] > 1.0f) colour[0] = 1.0f;
     if(colour[1] > 1.0f) colour[1] = 1.0f;
     if(colour[2] > 1.0f) colour[2] = 1.0f;
diff --git a/GL/private.h b/GL/private.h
index 120460d..6ef39b1 100644
--- a/GL/private.h
+++ b/GL/private.h
@@ -59,6 +59,7 @@ typedef struct {
     GLfloat diffuse[4];
     GLfloat specular[4];
     GLfloat ambient[4];
+    GLboolean is_directional;
 } LightSource;