better light

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

@@ -17,43 +17,68 @@ public class PieceShader extends ShaderProgram {
 			uniform mat4 projectionMatrix;
 			uniform mat4 viewMatrix;
 			uniform mat4 modelTransform;
-			uniform vec3 lightPosition = vec3(0, 1, 0);
+			uniform vec3 lightPosition = vec3(0, 10, 0);
 
 			out vec3 toLightVector;
+			out vec3 toCameraVector;
 			out vec3 surfaceNormal;
 
 			void main(void){
-				vec4 worldPos = modelTransform * vec4(position, 1.0);
 
-				toLightVector = lightPosition - worldPos.xyz;
-				surfaceNormal = (modelTransform * vec4(normal, 0.0)).xyz;
+				vec4 modelPos = modelTransform * vec4(position, 1.0);
+				vec4 globalNormal = modelTransform * vec4(normal, 1.0);
 
-				gl_Position = projectionMatrix * viewMatrix * worldPos;
+				gl_Position = projectionMatrix * viewMatrix * modelPos;
+
+				vec3 camPos = (inverse(viewMatrix) * vec4(0.0, 0.0, 0.0, 1.0)).xyz;
+
+				toLightVector = lightPosition - modelPos.xyz;
+
+				toCameraVector = camPos - position;
+				surfaceNormal = normalize(globalNormal.xyz);
 			}
+
 				""";
 
 	private static String fragmentShader = """
 			#version 330
 
 			in vec3 toLightVector;
+			in vec3 toCameraVector;
 			in vec3 surfaceNormal;
 
-			uniform vec3 modelColor = vec3(1, 1, 1);
+			uniform vec3 modelColor;
 
 			out vec4 out_color;
 
 			void main(void){
+				const float shineDamper = 10.0;
+				const float reflectivity = 1.0;
+
+				float lightDistance = length(toLightVector);
+
+				const vec3 attenuation = vec3(0.2, 0.1, 0.0);
+				float attenuationFactor = attenuation.x + attenuation.y * lightDistance + attenuation.z * lightDistance * lightDistance;
+
 				vec3 unitNormal = normalize(surfaceNormal);
 				vec3 unitLightVector = normalize(toLightVector);
+				vec3 unitCamVector = normalize(toCameraVector);
 
-				float diffuse = max(0.5, dot(unitNormal, unitLightVector));
+				vec3 lightDirection = -unitLightVector;
+				vec3 reflectedLightDirection = reflect(lightDirection, unitNormal);
 
-				float brightness = diffuse;
+				float diffuse = max(0.2, dot(unitNormal, unitLightVector));
 
-				out_color = vec4(modelColor, 1.0) * brightness;
+				float specularFactor = max(0.0, dot(reflectedLightDirection, unitCamVector));
+				float specular = pow(specularFactor, shineDamper) * reflectivity;
+
+				float brightness = (diffuse + specular) / attenuationFactor;
+
+				out_color = brightness * vec4(modelColor, 1.0);
 				out_color.w = 1.0;
 
 			}
+
 				""";
 
 	private int location_ProjectionMatrix = 0;