Initial commit

resources/shaders/fragment/phong.frag

@@ -0,0 +1,94 @@
+#version 330
+// Color input from Vertex shader
+in vec3 vNormal;
+in vec3 vPosition;
+
+// Final fragment fColor
+out vec4 fColor;
+
+// Light object and camera position vectors
+uniform vec3 uCameraPosition;
+struct Light {
+  vec3 position;
+
+  // Light colors RGB value
+  vec3 ambient;
+  vec3 diffuse;
+  vec3 specular;
+};
+uniform Light uLight;
+
+struct Material {
+  // Strength ranges 0.0f - 1.0f
+  float ambientStrength;
+  float diffuseStrength;
+  float specularStrength;
+  // 32, 64, 128, 256
+  float shine;
+
+  // Material color values
+  vec3 ambient;
+  vec3 diffuse;
+  vec3 specular;
+};
+uniform Material uMaterial;
+
+struct Result {
+  vec3 ambient;
+  vec3 diffuse;
+  vec3 specular;
+  vec3 sum;
+};
+
+void SumResult(inout Result result)
+{
+  result.sum = result.ambient + result.diffuse + result.specular;
+}
+
+void main()
+{
+  // A struct to store lighting results as we finish calculating them
+  // Valuse stored here will be applied to the final output of our shader
+  Result result;
+
+  // Ambient lighting
+  result.ambient =  (uLight.ambient * uMaterial.ambient) * uMaterial.ambientStrength;
+
+  //
+  // Diffuse lighting
+
+  // Normalize the provided normal vector
+  // + Creates a vector with length of 1 in the same direction as vNormal
+  vec3 norm = normalize(vNormal);
+  // Get a vector from this frag to the lightSoruce
+  vec3 lightDir = normalize(uLight.position - vPosition);
+  // As the normal vector approaches an angle looking at lightDir vector
+  // + If this is negative, the frag is on a surface opposite of the lightSource
+  float diff = max(dot(norm, lightDir), 0.0f);
+  result.diffuse = (uLight.diffuse * diff * uMaterial.diffuse) * uMaterial.diffuseStrength;
+
+  //
+  // Specular lighting
+
+  // Get a vector from the camera to the fragment as our viewDir
+  vec3 viewDir = normalize(uCameraPosition - vPosition);
+  // Since lightDir is already a vector from this frag to the light source
+  // reflectionDir is the opposite; A vector from the light to the frag
+  vec3 reflectDir = reflect(-lightDir, norm);
+
+  // Use dot product to check if viewDir and reflectDir angles are intersecting
+  // -1.0f if they are opposite; 1.0 if they are looking at each other directly
+  // + If this is negative, the lightSource is behind the player; Ignore it
+  float angleAlpha = max(dot(viewDir, reflectDir), 0.0f);
+  // As the angleAlpha approaches 1, raise to the power of uMaterial.shine
+  float spec = pow(angleAlpha, uMaterial.shine);
+  // Apply specular result to the
+  result.specular = (uLight.specular * uMaterial.specular * spec) * uMaterial.specularStrength;
+
+  //
+  // Final calculation
+  SumResult(result);
+
+  // Final output
+  fColor = vec4(result.sum, 1.0f); // Reapply alpha for opacity
+}