Correct for non uniform scale in lighting

core/Shaders/Shader.cpp

@@ -53,6 +53,10 @@ void Shader::UpdateProjection(Matrix projection) {
   glUniformMatrix4fv(glGetUniformLocation(id, "PROJECTION"), 1, GL_FALSE, glm::value_ptr(projection));
 }
 
+void Shader::UpdateNormal(glm::mat3 normal) {
+  glUniformMatrix3fv(glGetUniformLocation(id, "NORMAL"), 1, GL_FALSE, glm::value_ptr(normal));
+}
+
 void Shader::UpdateMaterial(Material material) {
   glUniform1i(glGetUniformLocation(id, "material.usesTex"), (int) material.usesTex);
   if (material.usesTex) {

core/Shaders/Shader.h

@@ -16,6 +16,7 @@ public:
   void UpdateView(Matrix view);
   void UpdateModel(Matrix model);
   void UpdateProjection(Matrix projection);
+  void UpdateNormal(glm::mat3 normal);
 
   void UpdateMaterial(Material material);
   

core/Skybox.cpp

@@ -74,6 +74,9 @@ Skybox *Skybox::FromFiles(const char *right, const char* left, const char* top,
   const char* files[] = {right, left, top, bottom, front, back};
   for (int i = 0; i < 6; i++) {
     data = stbi_load(files[i], &width, &height, &nrChannels, 3);
+    if (!data) {
+      Util::Die("Could not load skybox image ", files[i]);
+    }
     glTexImage2D(GL_TEXTURE_CUBE_MAP_POSITIVE_X + i,
 		 0, GL_RGB, width, height, 0, GL_RGB, GL_UNSIGNED_BYTE, data);
     stbi_image_free(data);

core/couch.cpp

@@ -46,6 +46,7 @@ void render(Node *curr, Shader *shader, Matrix model) {
       model = glm::translate(model, spatial->transform.position);
       model = glm::scale(model, spatial->transform.scale);
       shader->UpdateModel(model);
+      shader->UpdateNormal(glm::mat3(glm::transpose(glm::inverse(model))));
     }
     Mesh *mesh = dynamic_cast<Mesh*>(curr);
     mesh->Draw(shader);

demo/main.lua

@@ -37,12 +37,12 @@ function init()
    couch.Node.GetRoot().children:Append(light)
 
    skybox = couch.Skybox.FromFiles(
-      "skybox/right.jpg",
-      "skybox/left.jpg",
-      "skybox/top.jpg",
-      "skybox/bottom.jpg",
-      "skybox/front.jpg",
-      "skybox/back.jpg"
+      "skybox/px.png",
+      "skybox/nx.png",
+      "skybox/py.png",
+      "skybox/ny.png",
+      "skybox/pz.png",
+      "skybox/nz.png"
    )
    couch.Node.GetRoot().children:Append(skybox)
    

roadmap.md

@@ -58,3 +58,4 @@ calling it from the lua file, so stubs aren't necessary to prevent a crash
 I'm a bit happier with the system now, I think it's time I started the lighting.
 We're going to use a pretty basic Phong lighting system, with 
 Flat and Garourd shaders available (This was all that was available on the PSX!)
+

shaders/flat.frag

@@ -1,7 +1,6 @@
 #version 330 core
 
 noperspective in vec2 UV;
-in vec3 NORMAL;
 
 in vec3 AMBIENT;
 in vec3 DIFFUSE;

shaders/flat.vert

@@ -7,9 +7,9 @@ layout (location = 2) in vec2 uv;
 uniform mat4 MODEL;
 uniform mat4 VIEW;
 uniform mat4 PROJECTION;
+uniform mat3 NORMAL;
 
 noperspective out vec2 UV; // PSX use affine texture mapping
-out vec3 NORMAL;
 
 out vec3 AMBIENT;
 out vec3 DIFFUSE;
@@ -46,18 +46,19 @@ void main() {
 
   UV = uv;
 
-  NORMAL = (VIEW * MODEL * vec4(normal, 0.0)).xyz;
+  vec3 my_normal = (VIEW * MODEL * vec4(normal, 0.0)).xyz;
+  my_normal *= NORMAL;
 
   // Flat shading, we compute light per vertex
   AMBIENT = directionalLight.ambient * directionalLight.color * material.ambient;
 
   vec3 direction = -(VIEW * vec4(directionalLight.direction, 0.0)).xyz;
-  float diff = dot(normalize(direction), normalize(NORMAL));
+  float diff = dot(normalize(direction), normalize(my_normal));
   diff = max(diff, 0.0);
   DIFFUSE = directionalLight.diffuse * diff * directionalLight.color * material.diffuse;
 
   vec3 viewDir = normalize((VIEW * MODEL * vec4(pos, 1.0)).xyz);
-  vec3 reflectionDir = reflect(normalize(direction), normalize(NORMAL));
+  vec3 reflectionDir = reflect(normalize(direction), normalize(my_normal));
   float spec = dot(viewDir, reflectionDir);
   spec = max(spec, 0.0);
   spec = pow(spec, material.shininess);