1 files changed, 75 insertions, 1 deletions

diff --git a/assets/shaders/blinn_phong.frag b/assets/shaders/blinn_phong.frag
index a284948..095b19a 100644
--- a/assets/shaders/blinn_phong.frag
+++ b/assets/shaders/blinn_phong.frag
@@ -9,6 +9,25 @@ struct Material {
     float shininess;
 };
 
+struct DirLight {
+    vec3 direction;
+    vec3 ambient;
+    vec3 diffuse;
+    vec3 specular;
+};
+
+struct PointLight {
+    vec3 position;
+    // fall off properties
+    float constant;
+    float linear;
+    float quadratic;
+
+    vec3 ambient;
+    vec3 diffuse;
+    vec3 specular;
+};
+
 in VS_OUT {
   vec3 FragPos;
   vec3 Normal;
@@ -16,6 +35,61 @@ in VS_OUT {
   vec4 FragPosLightSpace;
 } fs_in;
 
+// --- Uniforms
+#define NUM_POINT_LIGHTS 4
+uniform vec3 viewPos;
+uniform Material material;
+uniform DirLight dirLight;
+uniform PointLight pointLights[NUM_POINT_LIGHTS];
+
+// --- Function prototypes
+vec3 CalcDirLight(DirLight light, vec3 normal, vec3 viewDir);
+vec3 CalcPointLight(PointLight light, vec3 normal, vec3 fragPos, vec3 viewDir);
+
 void main() {
-  FragColor = vec4(1.0);
+  vec3 norm = normalize(fs_in.Normal);
+  vec3 viewDir = normalize(viewPos - fs_in.FragPos);
+
+  vec3 result = CalcDirLight(dirLight, norm, viewDir);
+  for (int i = 0; i < 4; i++) {
+    result += CalcPointLight(pointLights[i], norm, fs_in.FragPos, viewDir);
+  }
+
+  FragColor = vec4(result, 1.0);
+}
+
+vec3 CalcDirLight(DirLight light, vec3 normal, vec3 viewDir)
+{
+    vec3 lightDir = normalize(-light.direction);
+    // diffuse shading
+    float diff = max(dot(normal, lightDir), 0.0);
+    // specular shading
+    vec3 reflectDir = reflect(-lightDir, normal);
+    float spec = pow(max(dot(viewDir, reflectDir), 0.0), material.shininess);
+    // combine result
+    vec3 ambient = light.ambient * vec3(texture(material.diffuse, fs_in.TexCoords));
+    vec3 diffuse = light.diffuse * diff * vec3(texture(material.diffuse, fs_in.TexCoords));
+    vec3 specular = light.specular * spec * vec3(texture(material.specular, fs_in.TexCoords));
+    return (ambient + diffuse + specular);
+}
+
+vec3 CalcPointLight(PointLight light, vec3 normal, vec3 fragPos, vec3 viewDir)
+{
+    vec3 lightDir = normalize(light.position - fragPos);
+    // diffuse
+    float diff = max(dot(normal, lightDir), 0.0);
+    // specular
+    vec3 reflectDir = reflect(-lightDir, normal);
+    float spec = pow(max(dot(viewDir, reflectDir), 0.0), material.shininess);
+    // attentuation
+    float distance = length(light.position - fragPos);
+    float attentuation = 1.0 / (light.constant + light.linear * distance * light.quadratic * (distance * distance));
+    // result
+    vec3 ambient = light.ambient * vec3(texture(material.diffuse, fs_in.TexCoords));
+    vec3 diffuse = light.diffuse * diff * vec3(texture(material.diffuse, fs_in.TexCoords));
+    vec3 specular = light.specular * spec * vec3(texture(material.specular, fs_in.TexCoords));
+    ambient *= attentuation;
+    diffuse *= attentuation;
+    specular *= attentuation;
+    return (ambient + diffuse + specular);
 }
\ No newline at end of file