29 lines
1.1 KiB
GLSL
29 lines
1.1 KiB
GLSL
#version 110
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// normalized values for (-0.6/1.31, 0.6/1.31, 1./1.31)
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const vec3 LIGHT_TOP_DIR = vec3(-0.4574957, 0.4574957, 0.7624929);
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const vec3 LIGHT_FRONT_DIR = vec3(0.0, 0.0, 1.0);
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// x = ambient, y = top diffuse, z = front diffuse, w = global
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uniform vec4 light_intensity;
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uniform vec4 uniform_color;
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varying vec3 eye_normal;
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void main()
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{
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vec3 normal = normalize(eye_normal);
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// Compute the cos of the angle between the normal and lights direction. The light is directional so the direction is constant for every vertex.
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// Since these two are normalized the cosine is the dot product. Take the abs value to light the lines no matter in which direction the normal points.
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float NdotL = abs(dot(normal, LIGHT_TOP_DIR));
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float intensity = light_intensity.x + NdotL * light_intensity.y;
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// Perform the same lighting calculation for the 2nd light source.
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NdotL = abs(dot(normal, LIGHT_FRONT_DIR));
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intensity += NdotL * light_intensity.z;
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gl_FragColor = vec4(uniform_color.rgb * light_intensity.w * intensity, uniform_color.a);
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}
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