Start work on lighting

shaders/flat.frag

@@ -1,6 +1,7 @@
 #version 330 core
 
 in vec3 UV;
+in vec3 NORMAL;
 
 out vec4 FragColor;
 
@@ -10,9 +11,19 @@ struct Material {
   sampler2D tex;
   bool usesTex;
   float alphaScissor;
+  bool unshaded;
+};
+
+struct DirectionalLight {
+  vec3 direction;
+  vec3 color;
+  float ambient;
+  float diffuse;
+  float specular;
 };
 
 uniform Material material;
+uniform DirectionalLight directionalLight;
 
 void main() {
   FragColor = vec4(0.0);
@@ -25,4 +36,10 @@ void main() {
   if (FragColor.w < material.alphaScissor) {
     discard;
   }
+
+  if (!material.unshaded) {
+    vec3 ambient = directionalLight.ambient * directionalLight.color;
+    vec3 diffuse = directionalLight.diffuse * reflect(directionalLight.direction, NORMAL) * directionalLight.color;
+    FragColor *= vec4(ambient, 1.0);
+  }
 }

shaders/flat.vert

@@ -1,16 +1,19 @@
 #version 330 core
 
 layout (location = 0) in vec3 pos;
-layout (location = 1) in vec2 uv;
+layout (location = 1) in vec3 normal;
+layout (location = 2) in vec2 uv;
 
 uniform mat4 MODEL;
 uniform mat4 VIEW;
 uniform mat4 PROJECTION;
 
 out vec3 UV;
+out vec3 NORMAL;
 
 void main() {
   vec4 vertex = PROJECTION * VIEW * MODEL * vec4(pos, 1.0);
   gl_Position = vertex;
   UV = vec3(uv * vertex.z, vertex.z);
+  NORMAL = normal;
 }

shaders/screen.vert

@@ -1,7 +1,8 @@
 #version 330 core
 
 layout (location = 0) in vec3 pos;
-layout (location = 1) in vec2 uv;
+layout (location = 1) in vec3 normal;
+layout (location = 2) in vec2 uv;
 
 out vec2 UV;