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);
 }

shaders/triangle.vert

@@ -3,8 +3,9 @@
 layout(location = 0) in vec3 position; // Vertex position
 layout(location = 1) in vec3 normal;   // Vertex normal
 layout(location = 2) in vec2 texCoord; // Vertex texture coordinate
-out vec3 Color; // Output color to the fragment shader
-out vec2 TexCoord; // Output texture coordinate to the fragment shader
+out vec3 Normal;
+out vec3 FragPos;  
+out vec2 TexCoord;
 
 uniform mat4 model;
 uniform mat4 view;
@@ -12,6 +13,7 @@ uniform mat4 projection;
 
 void main() {
     gl_Position = projection * view * model * vec4(position, 1.0); // Apply transformation matrices
-    Color = normal * 0.5 + 0.5; // Simple coloring based on normal
-    TexCoord = texCoord; // Pass through the texture coordinate
+    FragPos = vec3(model * vec4(position, 1.0));
+    Normal = mat3(transpose(inverse(model))) * normal;
+    TexCoord = texCoord;
 }

shaders/triangle_light_source.frag

@@ -0,0 +1,7 @@
+#version 330 core
+out vec4 FragColor;
+
+void main()
+{
+    FragColor = vec4(1.0); // set all 4 vector values to 1.0
+}