better light

app/src/main/java/chess/view/DDDrender/shader/BoardShader.java

@@ -12,16 +12,26 @@ public class BoardShader extends ShaderProgram {
 
 			uniform mat4 viewMatrix;
 			uniform mat4 projectionMatrix;
-			uniform vec3 lightPosition;
+			uniform vec3 lightPosition = vec3(0, 10, 0);
 
 			flat out vec3 pass_color;
+
 			out vec3 toLightVector;
+			out vec3 toCameraVector;
+			out vec3 surfaceNormal;
 
 			void main(void){
+				const vec4 normal = vec4(0.0, 1.0, 0.0, 1.0);
+
 				gl_Position = projectionMatrix * viewMatrix * vec4(position, 1.0);
 
+				vec3 camPos = (inverse(viewMatrix) * vec4(0.0, 0.0, 0.0, 1.0)).xyz;
+
 				toLightVector = lightPosition - position;
 
+				toCameraVector = camPos - position;
+				surfaceNormal = (normal).xyz;
+
 				pass_color = color;
 			}
 
@@ -33,6 +43,8 @@ public class BoardShader extends ShaderProgram {
 			flat in vec3 pass_color;
 
 			in vec3 toLightVector;
+			in vec3 toCameraVector;
+			in vec3 surfaceNormal;
 
 			out vec4 out_color;
 
@@ -42,18 +54,22 @@ public class BoardShader extends ShaderProgram {
 
 				float lightDistance = length(toLightVector);
 
-				const vec3 attenuation = vec3(0.3, 0.03, 0);
+				const vec3 attenuation = vec3(0.2, 0.1, 0.0);
 				float attenuationFactor = attenuation.x + attenuation.y * lightDistance + attenuation.z * lightDistance * lightDistance;
 
-				vec3 unitNormal = vec3(0, 1, 0);
+				vec3 unitNormal = normalize(surfaceNormal);
 				vec3 unitLightVector = normalize(toLightVector);
+				vec3 unitCamVector = normalize(toCameraVector);
 
 				vec3 lightDirection = -unitLightVector;
 				vec3 reflectedLightDirection = reflect(lightDirection, unitNormal);
 
 				float diffuse = max(0.2, dot(unitNormal, unitLightVector));
 
-				float brightness = diffuse / attenuationFactor;
+				float specularFactor = max(0.0, dot(reflectedLightDirection, unitCamVector));
+				float specular = pow(specularFactor, shineDamper) * reflectivity;
+
+				float brightness = (diffuse + specular) / attenuationFactor;
 
 				out_color = brightness * vec4(pass_color, 1.0);
 				out_color.w = 1.0;