Tech ENABLE_GLBEGIN_GLEND_SHADERS_ATTRIBUTES - Use vertex attributes and matrices in shaders.

Shader: gouraud_light_instanced_attr - Instanced options in gcode preview

resources/shaders/gouraud_light_instanced_attr.vs

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+#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 INTENSITY_AMBIENT    0.3
+
+// vertex attributes
+attribute vec3 v_position;
+attribute vec3 v_normal;
+// instance attributes
+attribute vec3 i_offset;
+attribute vec2 i_scales;
+
+uniform mat4 view_model_matrix;
+uniform mat4 projection_matrix;
+uniform mat3 normal_matrix;
+
+// x = tainted, y = specular;
+varying vec2 intensity;
+
+void main()
+{
+    // First transform the normal into camera space and normalize the result.
+    vec3 eye_normal = normalize(normal_matrix * v_normal);
+    
+    // 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;
+    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);
+    vec4 eye_position = view_model_matrix * world_position;
+    intensity.y = LIGHT_TOP_SPECULAR * pow(max(dot(-normalize(eye_position.xyz), reflect(-LIGHT_TOP_DIR, eye_normal)), 0.0), LIGHT_TOP_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;
+
+    gl_Position = projection_matrix * eye_position;
+}