Create inspection lighting scene

Greatly improves brightness and contrast. Colours are now rendered accurately in 3D visualization.

Employs three-point lighting principles: key light, back light, and fill light.

We use multiple key and fill lights, not for visual aesthetics, but to improve illumination of scene for inspection when rotating objects.

resources/shaders/gouraud.vs

@@ -1,22 +1,28 @@
 #version 110
 
-#define INTENSITY_CORRECTION 0.6
-
-// normalized values for (-0.6/1.31, 0.6/1.31, 1./1.31)
-const vec3 LIGHT_TOP_DIR = vec3(-0.4574957, 0.4574957, 0.7624929);
-#define LIGHT_TOP_DIFFUSE    (0.8 * INTENSITY_CORRECTION)
-#define LIGHT_TOP_SPECULAR   (0.125 * INTENSITY_CORRECTION)
-#define LIGHT_TOP_SHININESS  20.0
-
-// normalized values for (1./1.43, 0.2/1.43, 1./1.43)
-const vec3 LIGHT_FRONT_DIR = vec3(0.6985074, 0.1397015, 0.6985074);
-#define LIGHT_FRONT_DIFFUSE  (0.3 * INTENSITY_CORRECTION)
-//#define LIGHT_FRONT_SPECULAR (0.0 * INTENSITY_CORRECTION)
-//#define LIGHT_FRONT_SHININESS 5.0
-
-#define INTENSITY_AMBIENT    0.3
-
-const vec3 ZERO = vec3(0.0, 0.0, 0.0);
+// Two key lights
+const vec3 LIGHT_KEY_TOP_DIR = vec3(-1.0, 0.75, 1.0);
+const vec3 LIGHT_KEY_BOT_DIR = vec3(-1.0, -0.75, 1.0);
+#define LIGHT_KEY_DIFFUSE   0.16
+#define LIGHT_KEY_SPECULAR  0.008
+
+// One back light
+const vec3 LIGHT_BACK_DIR = vec3(0.75, 0.5, -1.0);
+#define LIGHT_BACK_DIFFUSE  0.3
+#define LIGHT_BACK_SPECULAR  0.015
+
+// Four fill lights
+const vec3 LIGHT_FILL_TOP_FRONT_DIR = vec3(1.0, 0.75, 1.0);
+const vec3 LIGHT_FILL_BOT_FRONT_DIR = vec3(1.0, -0.75, 1.0);
+const vec3 LIGHT_FILL_TOP_MIDDLE_DIR = vec3(0.0, 1.0, 0.8);
+const vec3 LIGHT_FILL_BOT_MIDDLE_DIR = vec3(0.0, -1.0, 0.8);
+const vec3 LIGHT_FILL_CENTER_FRONT_DIR = vec3(0.0, 0.0, 1.0);
+
+#define LIGHT_FILL_DIFFUSE  0.1
+#define LIGHT_FILL_SPECULAR  0.004
+
+#define LIGHT_SHININESS 7.0
+#define INTENSITY_AMBIENT   0.3
 
 struct SlopeDetection
 {
@@ -33,7 +39,7 @@ uniform vec2 z_range;
 // Clipping plane - general orientation. Used by the SLA gizmo.
 uniform vec4 clipping_plane;
 
-// x = diffuse, y = specular;
+// x = diffuse, y = specular
 varying vec2 intensity;
 
 varying vec3 clipping_planes_dots;
@@ -47,18 +53,48 @@ void main()
 {
 	// First transform the normal into camera space and normalize the result.
 	eye_normal = normalize(gl_NormalMatrix * gl_Normal);
+	vec3 position = (gl_ModelViewMatrix * gl_Vertex).xyz;
 
 	// Compute the cos of the angle between the normal and lights direction. The light is directional so the direction is constant for every vertex.
 	// Since these two are normalized the cosine is the dot product. We also need to clamp the result to the [0,1] range.
-	float NdotL = max(dot(eye_normal, LIGHT_TOP_DIR), 0.0);
 
-	intensity.x = INTENSITY_AMBIENT + NdotL * LIGHT_TOP_DIFFUSE;
-	vec3 position = (gl_ModelViewMatrix * gl_Vertex).xyz;
-	intensity.y = LIGHT_TOP_SPECULAR * pow(max(dot(-normalize(position), reflect(-LIGHT_TOP_DIR, eye_normal)), 0.0), LIGHT_TOP_SHININESS);
+    // Ambient light
+    intensity.x = INTENSITY_AMBIENT;
+
+	// Key lights
+	float NdotL = max(dot(eye_normal, LIGHT_KEY_TOP_DIR), 0.0);
+	intensity.x += NdotL * LIGHT_KEY_DIFFUSE;
+	intensity.y = LIGHT_KEY_SPECULAR * pow(max(dot(-normalize(position), reflect(-LIGHT_KEY_TOP_DIR, eye_normal)), 0.0), LIGHT_SHININESS);
+
+	NdotL = max(dot(eye_normal, LIGHT_KEY_BOT_DIR), 0.0);
+	intensity.x += NdotL * LIGHT_KEY_DIFFUSE;
+	intensity.y += LIGHT_KEY_SPECULAR * pow(max(dot(-normalize(position), reflect(-LIGHT_KEY_BOT_DIR, eye_normal)), 0.0), LIGHT_SHININESS);
+
+	// Back light
+	NdotL = max(dot(eye_normal, LIGHT_BACK_DIR), 0.0);
+	intensity.x += NdotL * LIGHT_BACK_DIFFUSE;
+    intensity.y += LIGHT_BACK_SPECULAR * pow(max(dot(-normalize(position), reflect(-LIGHT_BACK_DIR, eye_normal)), 0.0), LIGHT_SHININESS);
+
+	// Fill lights
+    NdotL = max(dot(eye_normal, LIGHT_FILL_TOP_FRONT_DIR), 0.0);
+    intensity.x += NdotL * LIGHT_FILL_DIFFUSE;
+    intensity.y += LIGHT_FILL_SPECULAR * pow(max(dot(-normalize(position), reflect(-LIGHT_FILL_TOP_FRONT_DIR, eye_normal)), 0.0), LIGHT_SHININESS);
+
+    NdotL = max(dot(eye_normal, LIGHT_FILL_BOT_FRONT_DIR), 0.0);
+    intensity.x += NdotL * LIGHT_FILL_DIFFUSE;
+    intensity.y += LIGHT_FILL_SPECULAR * pow(max(dot(-normalize(position), reflect(-LIGHT_FILL_BOT_FRONT_DIR, eye_normal)), 0.0), LIGHT_SHININESS);
+
+    NdotL = max(dot(eye_normal, LIGHT_FILL_TOP_MIDDLE_DIR), 0.0);
+    intensity.x += NdotL * LIGHT_FILL_DIFFUSE;
+    intensity.y += LIGHT_FILL_SPECULAR * pow(max(dot(-normalize(position), reflect(-LIGHT_FILL_TOP_MIDDLE_DIR, eye_normal)), 0.0), LIGHT_SHININESS);
+
+    NdotL = max(dot(eye_normal, LIGHT_FILL_BOT_MIDDLE_DIR), 0.0);
+    intensity.x += NdotL * LIGHT_FILL_DIFFUSE;
+    intensity.y += LIGHT_FILL_SPECULAR * pow(max(dot(-normalize(position), reflect(-LIGHT_FILL_BOT_MIDDLE_DIR, eye_normal)), 0.0), LIGHT_SHININESS);
 
-	// Perform the same lighting calculation for the 2nd light source (no specular applied).
-	NdotL = max(dot(eye_normal, LIGHT_FRONT_DIR), 0.0);
-	intensity.x += NdotL * LIGHT_FRONT_DIFFUSE;
+    NdotL = max(dot(eye_normal, LIGHT_FILL_CENTER_FRONT_DIR), 0.0);
+    intensity.x += NdotL * LIGHT_FILL_DIFFUSE;
+    intensity.y += LIGHT_FILL_SPECULAR * pow(max(dot(-normalize(position), reflect(-LIGHT_FILL_CENTER_FRONT_DIR, eye_normal)), 0.0), LIGHT_SHININESS);
 
     model_pos = gl_Vertex;
     // Point in homogenous coordinates.

resources/shaders/gouraud_light.vs

@@ -1,38 +1,78 @@
 #version 110
 
-#define INTENSITY_CORRECTION 0.6
+// Two key lights
+const vec3 LIGHT_KEY_TOP_DIR = vec3(-1.0, 0.75, 1.0);
+const vec3 LIGHT_KEY_BOT_DIR = vec3(-1.0, -0.75, 1.0);
+#define LIGHT_KEY_DIFFUSE   0.16
+#define LIGHT_KEY_SPECULAR  0.008
 
-// normalized values for (-0.6/1.31, 0.6/1.31, 1./1.31)
-const vec3 LIGHT_TOP_DIR = vec3(-0.4574957, 0.4574957, 0.7624929);
-#define LIGHT_TOP_DIFFUSE    (0.8 * INTENSITY_CORRECTION)
-#define LIGHT_TOP_SPECULAR   (0.125 * INTENSITY_CORRECTION)
-#define LIGHT_TOP_SHININESS  20.0
+// One back light
+const vec3 LIGHT_BACK_DIR = vec3(0.75, 0.5, -1.0);
+#define LIGHT_BACK_DIFFUSE  0.3
+#define LIGHT_BACK_SPECULAR  0.015
 
-// normalized values for (1./1.43, 0.2/1.43, 1./1.43)
-const vec3 LIGHT_FRONT_DIR = vec3(0.6985074, 0.1397015, 0.6985074);
-#define LIGHT_FRONT_DIFFUSE  (0.3 * INTENSITY_CORRECTION)
+// Four fill lights
+const vec3 LIGHT_FILL_TOP_FRONT_DIR = vec3(1.0, 0.75, 1.0);
+const vec3 LIGHT_FILL_BOT_FRONT_DIR = vec3(1.0, -0.75, 1.0);
+const vec3 LIGHT_FILL_TOP_MIDDLE_DIR = vec3(0.0, 1.0, 0.8);
+const vec3 LIGHT_FILL_BOT_MIDDLE_DIR = vec3(0.0, -1.0, 0.8);
+const vec3 LIGHT_FILL_CENTER_FRONT_DIR = vec3(0.0, 0.0, 1.0);
 
-#define INTENSITY_AMBIENT    0.3
+#define LIGHT_FILL_DIFFUSE  0.1
+#define LIGHT_FILL_SPECULAR  0.004
 
-// x = tainted, y = specular;
+#define LIGHT_SHININESS 7.0
+#define INTENSITY_AMBIENT   0.3
+
+// x = diffuse, y = specular
 varying vec2 intensity;
 
 void main()
 {
     // First transform the normal into camera space and normalize the result.
     vec3 normal = normalize(gl_NormalMatrix * gl_Normal);
+    vec3 position = (gl_ModelViewMatrix * gl_Vertex).xyz;
 
     // Compute the cos of the angle between the normal and lights direction. The light is directional so the direction is constant for every vertex.
     // Since these two are normalized the cosine is the dot product. We also need to clamp the result to the [0,1] range.
-    float NdotL = max(dot(normal, LIGHT_TOP_DIR), 0.0);
 
-    intensity.x = INTENSITY_AMBIENT + NdotL * LIGHT_TOP_DIFFUSE;
-    vec3 position = (gl_ModelViewMatrix * gl_Vertex).xyz;
-    intensity.y = LIGHT_TOP_SPECULAR * pow(max(dot(-normalize(position), reflect(-LIGHT_TOP_DIR, normal)), 0.0), LIGHT_TOP_SHININESS);
+    // Ambient light
+    intensity.x = INTENSITY_AMBIENT;
+
+    // Key lights
+    float NdotL = max(dot(normal, LIGHT_KEY_TOP_DIR), 0.0);
+    intensity.x += NdotL * LIGHT_KEY_DIFFUSE;
+    intensity.y = LIGHT_KEY_SPECULAR * pow(max(dot(-normalize(position), reflect(-LIGHT_KEY_TOP_DIR, normal)), 0.0), LIGHT_SHININESS);
+
+    NdotL = max(dot(normal, LIGHT_KEY_BOT_DIR), 0.0);
+    intensity.x += NdotL * LIGHT_KEY_DIFFUSE;
+    intensity.y += LIGHT_KEY_SPECULAR * pow(max(dot(-normalize(position), reflect(-LIGHT_KEY_BOT_DIR, normal)), 0.0), LIGHT_SHININESS);
+
+    // Back light
+    NdotL = max(dot(normal, LIGHT_BACK_DIR), 0.0);
+    intensity.x += NdotL * LIGHT_BACK_DIFFUSE;
+    intensity.y += LIGHT_BACK_SPECULAR * pow(max(dot(-normalize(position), reflect(-LIGHT_BACK_DIR, normal)), 0.0), LIGHT_SHININESS);
+
+    // Fill lights
+    NdotL = max(dot(normal, LIGHT_FILL_TOP_FRONT_DIR), 0.0);
+    intensity.x += NdotL * LIGHT_FILL_DIFFUSE;
+    intensity.y += LIGHT_FILL_SPECULAR * pow(max(dot(-normalize(position), reflect(-LIGHT_FILL_TOP_FRONT_DIR, normal)), 0.0), LIGHT_SHININESS);
+
+    NdotL = max(dot(normal, LIGHT_FILL_BOT_FRONT_DIR), 0.0);
+    intensity.x += NdotL * LIGHT_FILL_DIFFUSE;
+    intensity.y += LIGHT_FILL_SPECULAR * pow(max(dot(-normalize(position), reflect(-LIGHT_FILL_BOT_FRONT_DIR, normal)), 0.0), LIGHT_SHININESS);
+
+    NdotL = max(dot(normal, LIGHT_FILL_TOP_MIDDLE_DIR), 0.0);
+    intensity.x += NdotL * LIGHT_FILL_DIFFUSE;
+    intensity.y += LIGHT_FILL_SPECULAR * pow(max(dot(-normalize(position), reflect(-LIGHT_FILL_TOP_MIDDLE_DIR, normal)), 0.0), LIGHT_SHININESS);
+
+    NdotL = max(dot(normal, LIGHT_FILL_BOT_MIDDLE_DIR), 0.0);
+    intensity.x += NdotL * LIGHT_FILL_DIFFUSE;
+    intensity.y += LIGHT_FILL_SPECULAR * pow(max(dot(-normalize(position), reflect(-LIGHT_FILL_BOT_MIDDLE_DIR, normal)), 0.0), LIGHT_SHININESS);
 
-    // Perform the same lighting calculation for the 2nd light source (no specular applied).
-    NdotL = max(dot(normal, LIGHT_FRONT_DIR), 0.0);
-    intensity.x += NdotL * LIGHT_FRONT_DIFFUSE;
+    NdotL = max(dot(normal, LIGHT_FILL_CENTER_FRONT_DIR), 0.0);
+    intensity.x += NdotL * LIGHT_FILL_DIFFUSE;
+    intensity.y += LIGHT_FILL_SPECULAR * pow(max(dot(-normalize(position), reflect(-LIGHT_FILL_CENTER_FRONT_DIR, normal)), 0.0), LIGHT_SHININESS);
 
     gl_Position = ftransform();
 }

resources/shaders/gouraud_light_instanced.vs

@@ -1,18 +1,28 @@
 #version 110
 
-#define INTENSITY_CORRECTION 0.6
+// Two key lights
+const vec3 LIGHT_KEY_TOP_DIR = vec3(-1.0, 0.75, 1.0);
+const vec3 LIGHT_KEY_BOT_DIR = vec3(-1.0, -0.75, 1.0);
+#define LIGHT_KEY_DIFFUSE   0.16
+#define LIGHT_KEY_SPECULAR  0.008
 
-// normalized values for (-0.6/1.31, 0.6/1.31, 1./1.31)
-const vec3 LIGHT_TOP_DIR = vec3(-0.4574957, 0.4574957, 0.7624929);
-#define LIGHT_TOP_DIFFUSE    (0.8 * INTENSITY_CORRECTION)
-#define LIGHT_TOP_SPECULAR   (0.125 * INTENSITY_CORRECTION)
-#define LIGHT_TOP_SHININESS  20.0
+// One back light
+const vec3 LIGHT_BACK_DIR = vec3(0.75, 0.5, -1.0);
+#define LIGHT_BACK_DIFFUSE  0.3
+#define LIGHT_BACK_SPECULAR  0.015
 
-// normalized values for (1./1.43, 0.2/1.43, 1./1.43)
-const vec3 LIGHT_FRONT_DIR = vec3(0.6985074, 0.1397015, 0.6985074);
-#define LIGHT_FRONT_DIFFUSE  (0.3 * INTENSITY_CORRECTION)
+// Four fill lights
+const vec3 LIGHT_FILL_TOP_FRONT_DIR = vec3(1.0, 0.75, 1.0);
+const vec3 LIGHT_FILL_BOT_FRONT_DIR = vec3(1.0, -0.75, 1.0);
+const vec3 LIGHT_FILL_TOP_MIDDLE_DIR = vec3(0.0, 1.0, 0.8);
+const vec3 LIGHT_FILL_BOT_MIDDLE_DIR = vec3(0.0, -1.0, 0.8);
+const vec3 LIGHT_FILL_CENTER_FRONT_DIR = vec3(0.0, 0.0, 1.0);
 
-#define INTENSITY_AMBIENT    0.3
+#define LIGHT_FILL_DIFFUSE  0.1
+#define LIGHT_FILL_SPECULAR  0.004
+
+#define LIGHT_SHININESS 7.0
+#define INTENSITY_AMBIENT   0.3
 
 // vertex attributes
 attribute vec3 v_position;
@@ -21,26 +31,56 @@ attribute vec3 v_normal;
 attribute vec3 i_offset;
 attribute vec2 i_scales;
 
-// x = tainted, y = specular;
+// x = diffuse, y = specular
 varying vec2 intensity;
 
 void main()
 {
     // First transform the normal into camera space and normalize the result.
     vec3 eye_normal = normalize(gl_NormalMatrix * v_normal);
+    vec4 world_position = vec4(v_position * vec3(vec2(1.5 * i_scales.x), 1.5 * i_scales.y) + i_offset - vec3(0.0, 0.0, 0.5 * i_scales.y), 1.0);
+    vec3 eye_position = (gl_ModelViewMatrix * world_position).xyz;
 
     // Compute the cos of the angle between the normal and lights direction. The light is directional so the direction is constant for every vertex.
     // Since these two are normalized the cosine is the dot product. We also need to clamp the result to the [0,1] range.
-    float NdotL = max(dot(eye_normal, LIGHT_TOP_DIR), 0.0);
+
+    // Ambient light
+    intensity.x = INTENSITY_AMBIENT;
 
-    intensity.x = INTENSITY_AMBIENT + NdotL * LIGHT_TOP_DIFFUSE;
-    vec4 world_position = vec4(v_position * vec3(vec2(1.5 * i_scales.x), 1.5 * i_scales.y) + i_offset - vec3(0.0, 0.0, 0.5 * i_scales.y), 1.0);
-    vec3 eye_position = (gl_ModelViewMatrix * world_position).xyz;
-    intensity.y = LIGHT_TOP_SPECULAR * pow(max(dot(-normalize(eye_position), reflect(-LIGHT_TOP_DIR, eye_normal)), 0.0), LIGHT_TOP_SHININESS);
+    // Key lights
+    float NdotL = max(dot(eye_normal, LIGHT_KEY_TOP_DIR), 0.0);
+    intensity.x += NdotL * LIGHT_KEY_DIFFUSE;
+    intensity.y = LIGHT_KEY_SPECULAR * pow(max(dot(-normalize(eye_position), reflect(-LIGHT_KEY_TOP_DIR, eye_normal)), 0.0), LIGHT_SHININESS);
+
+    NdotL = max(dot(eye_normal, LIGHT_KEY_BOT_DIR), 0.0);
+    intensity.x += NdotL * LIGHT_KEY_DIFFUSE;
+    intensity.y += LIGHT_KEY_SPECULAR * pow(max(dot(-normalize(eye_position), reflect(-LIGHT_KEY_BOT_DIR, eye_normal)), 0.0), LIGHT_SHININESS);
+
+    // Back light
+    NdotL = max(dot(eye_normal, LIGHT_BACK_DIR), 0.0);
+    intensity.x += NdotL * LIGHT_BACK_DIFFUSE;
+    intensity.y += LIGHT_BACK_SPECULAR * pow(max(dot(-normalize(eye_position), reflect(-LIGHT_BACK_DIR, eye_normal)), 0.0), LIGHT_SHININESS);
+
+    // Fill lights
+    NdotL = max(dot(eye_normal, LIGHT_FILL_TOP_FRONT_DIR), 0.0);
+    intensity.x += NdotL * LIGHT_FILL_DIFFUSE;
+    intensity.y += LIGHT_FILL_SPECULAR * pow(max(dot(-normalize(eye_position), reflect(-LIGHT_FILL_TOP_FRONT_DIR, eye_normal)), 0.0), LIGHT_SHININESS);
+
+    NdotL = max(dot(eye_normal, LIGHT_FILL_BOT_FRONT_DIR), 0.0);
+    intensity.x += NdotL * LIGHT_FILL_DIFFUSE;
+    intensity.y += LIGHT_FILL_SPECULAR * pow(max(dot(-normalize(eye_position), reflect(-LIGHT_FILL_BOT_FRONT_DIR, eye_normal)), 0.0), LIGHT_SHININESS);
+
+    NdotL = max(dot(eye_normal, LIGHT_FILL_TOP_MIDDLE_DIR), 0.0);
+    intensity.x += NdotL * LIGHT_FILL_DIFFUSE;
+    intensity.y += LIGHT_FILL_SPECULAR * pow(max(dot(-normalize(eye_position), reflect(-LIGHT_FILL_TOP_MIDDLE_DIR, eye_normal)), 0.0), LIGHT_SHININESS);
+
+    NdotL = max(dot(eye_normal, LIGHT_FILL_BOT_MIDDLE_DIR), 0.0);
+    intensity.x += NdotL * LIGHT_FILL_DIFFUSE;
+    intensity.y += LIGHT_FILL_SPECULAR * pow(max(dot(-normalize(eye_position), reflect(-LIGHT_FILL_BOT_MIDDLE_DIR, eye_normal)), 0.0), LIGHT_SHININESS);
 
-    // Perform the same lighting calculation for the 2nd light source (no specular applied).
-    NdotL = max(dot(eye_normal, LIGHT_FRONT_DIR), 0.0);
-    intensity.x += NdotL * LIGHT_FRONT_DIFFUSE;
+    NdotL = max(dot(eye_normal, LIGHT_FILL_CENTER_FRONT_DIR), 0.0);
+    intensity.x += NdotL * LIGHT_FILL_DIFFUSE;
+    intensity.y += LIGHT_FILL_SPECULAR * pow(max(dot(-normalize(eye_position), reflect(-LIGHT_FILL_CENTER_FRONT_DIR, eye_normal)), 0.0), LIGHT_SHININESS);
 
     gl_Position = gl_ProjectionMatrix * vec4(eye_position, 1.0);
 }