basic lighting

shaders/triangle.frag

@@ -1,11 +1,34 @@
 #version 330 core
-
 out vec4 FragColor;
-in vec3 Color; // Input color from the vertex shader
-in vec2 TexCoord; // Input texture coordinate from the vertex shader
+in vec3 FragPos;  
+in vec3 Normal;
+in vec2 TexCoord;
 
+uniform vec3 objectColor;
+uniform vec3 lightColor;
+uniform vec3 lightPos;
+uniform vec3 viewPos;
 uniform sampler2D Texture1;
 
-void main() {
-    FragColor = texture(Texture1, TexCoord);
+void main()
+{
+    // ambient
+    float ambientStrength = 0.1;
+    vec3 ambient = ambientStrength * lightColor;
+  	
+    // diffuse 
+    vec3 norm = normalize(Normal);
+    vec3 lightDir = normalize(lightPos - FragPos);
+    float diff = max(dot(norm, lightDir), 0.0);
+    vec3 diffuse = diff * lightColor;
+
+    // specular
+    float specularStrength = 0.5;
+    vec3 viewDir = normalize(viewPos - FragPos);
+    vec3 reflectDir = normalize(reflect(-lightDir, norm));  
+    float spec = pow(max(dot(viewDir, reflectDir), 0.0), 32.0);
+    vec3 specular = specularStrength * spec * lightColor;
+
+    vec3 result = (ambient + diffuse + specular) * texture(Texture1, TexCoord).rgb;
+    FragColor = vec4(result, 1.0);
 }