49 lines
1.9 KiB
GLSL
49 lines
1.9 KiB
GLSL
#version 110
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#define INTENSITY_CORRECTION 0.6
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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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#define LIGHT_TOP_DIFFUSE (0.8 * INTENSITY_CORRECTION)
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#define LIGHT_TOP_SPECULAR (0.125 * INTENSITY_CORRECTION)
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#define LIGHT_TOP_SHININESS 20.0
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// normalized values for (1./1.43, 0.2/1.43, 1./1.43)
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const vec3 LIGHT_FRONT_DIR = vec3(0.6985074, 0.1397015, 0.6985074);
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#define LIGHT_FRONT_DIFFUSE (0.3 * INTENSITY_CORRECTION)
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#define INTENSITY_AMBIENT 0.3
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// vertex attributes
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attribute vec3 v_position;
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attribute vec3 v_normal;
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// instance attributes
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attribute vec3 i_offset;
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attribute vec2 i_scales;
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// x = tainted, y = specular;
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varying vec2 intensity;
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void main()
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{
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// First transform the normal into camera space and normalize the result.
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vec3 eye_normal = normalize(gl_NormalMatrix * v_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. We also need to clamp the result to the [0,1] range.
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float NdotL = max(dot(eye_normal, LIGHT_TOP_DIR), 0.0);
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intensity.x = INTENSITY_AMBIENT + NdotL * LIGHT_TOP_DIFFUSE;
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float width = 1.5 * i_scales.x;
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float height = 1.5 * i_scales.y;
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vec4 world_position = vec4(v_position * vec3(vec2(width), height) + i_offset - vec3(0.0, 0.0, 0.5 * i_scales.y), 1.0);
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vec3 eye_position = (gl_ModelViewMatrix * world_position).xyz;
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intensity.y = LIGHT_TOP_SPECULAR * pow(max(dot(-normalize(eye_position), reflect(-LIGHT_TOP_DIR, eye_normal)), 0.0), LIGHT_TOP_SHININESS);
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// Perform the same lighting calculation for the 2nd light source (no specular applied).
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NdotL = max(dot(eye_normal, LIGHT_FRONT_DIR), 0.0);
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intensity.x += NdotL * LIGHT_FRONT_DIFFUSE;
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gl_Position = gl_ProjectionMatrix * vec4(eye_position, 1.0);
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}
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