started fixing stuff with model imports

resources/backpack/backpack.mtl

@@ -0,0 +1,16 @@
+# Blender MTL File: 'None'
+# Material Count: 1
+
+newmtl Scene_-_Root
+Ns 225.000000
+Ka 1.000000 1.000000 1.000000
+Kd 0.800000 0.800000 0.800000
+Ks 0.500000 0.500000 0.500000
+Ke 0.0 0.0 0.0
+Ni 1.450000
+d 1.000000
+illum 2
+map_Kd diffuse.jpg
+map_Bump normal.png
+map_Ks specular.jpg
+

resources/backpack/source_attribution.txt

@@ -0,0 +1,3 @@
+Model by Berk Gedik, from: https://sketchfab.com/3d-models/survival-guitar-backpack-low-poly-799f8c4511f84fab8c3f12887f7e6b36
+
+Modified material assignment (Joey de Vries) for easier load in OpenGL model loading chapter, and renamed albedo to diffuse and metallic to specular to match non-PBR lighting setup.

resources/standard.frag

@@ -8,35 +8,25 @@ in vec3 Normal;
 
 uniform vec3 viewPosition;
 
-uniform sampler2D diffuse1;
-uniform sampler2D specular1;
-
 uniform vec3 phongAmbient;
 uniform vec3 phongDiffuse;
 uniform vec3 phongSpecular;
 uniform float phongShininess;
 
-uniform vec3 lightPos;
+uniform vec3 lightDirection;
 uniform vec3 lightAmbient;
 uniform vec3 lightDiffuse;
 uniform vec3 lightSpecular;
 
 void main() {
-    vec3 diffColor = texture(diffuse1, TexCoord).rgb;
-    vec3 specColor = texture(specular1, TexCoord).rgb;
-
-    vec3 ambient = (phongAmbient * diffColor) * lightAmbient;
-
     vec3 norm = normalize(Normal);
-    vec3 lightDir = normalize(lightPos - Position);
+    vec3 lightDir = normalize(-lightDirection);
+
+    vec3 ambient = (phongAmbient);
+
     float diffImpact = max(dot(norm, lightDir), 0.0);
-    vec3 diffuse = (phongDiffuse * diffImpact * diffColor) * lightDiffuse;
+    vec3 diffuse = (phongDiffuse * diffImpact);
 
-    vec3 viewDir = normalize(viewPosition - Position);
-    vec3 halfwayDir = normalize(lightDir + viewDir);
-    float specImpact = pow(max(dot(norm, halfwayDir), 0.0), phongShininess);
-    vec3 specular = (phongSpecular * specImpact * specColor) * lightSpecular;
-
-    vec3 result = ambient + diffuse + specular;
+    vec3 result = ambient + diffuse;
     FragColor = vec4(result, 1.0);
 }