68 lines
2.4 KiB
GLSL
68 lines
2.4 KiB
GLSL
#version 140
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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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in vec3 v_position;
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in vec3 v_normal;
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// instance attributes
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in vec3 i_offset;
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in vec2 i_scales;
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in mat4 instanceMatrix;
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uniform mat4 view_matrix;
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uniform mat4 projection_matrix;
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// x = tainted, y = specular;
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out vec2 intensity;
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mat3 inverse_mat3(mat3 m) {
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float a00 = m[0][0], a01 = m[0][1], a02 = m[0][2];
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float a10 = m[1][0], a11 = m[1][1], a12 = m[1][2];
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float a20 = m[2][0], a21 = m[2][1], a22 = m[2][2];
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float b01 = a22 * a11 - a12 * a21;
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float b11 = -a22 * a10 + a12 * a20;
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float b21 = a21 * a10 - a11 * a20;
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float det = a00 * b01 + a01 * b11 + a02 * b21;
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return mat3(b01, (-a22 * a01 + a02 * a21), (a12 * a01 - a02 * a11),
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b11, (a22 * a00 - a02 * a20), (-a12 * a00 + a02 * a10),
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b21, (-a21 * a00 + a01 * a20), (a11 * a00 - a01 * a10)) / det;
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}
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void main()
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{
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mat4 view_model_matrix = view_matrix * instanceMatrix;
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// First transform the normal into camera space and normalize the result.
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vec3 normal = normalize(transpose(inverse_mat3(mat3(view_model_matrix))) * 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(normal, LIGHT_TOP_DIR), 0.0);
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intensity.x = INTENSITY_AMBIENT + NdotL * LIGHT_TOP_DIFFUSE;
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vec4 position = view_model_matrix * vec4(v_position, 1.0);
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intensity.y = LIGHT_TOP_SPECULAR * pow(max(dot(-normalize(position.xyz), reflect(-LIGHT_TOP_DIR, 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(normal, LIGHT_FRONT_DIR), 0.0);
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intensity.x += NdotL * LIGHT_FRONT_DIFFUSE;
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gl_Position = projection_matrix * position;
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}
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