86 lines
No EOL
2.4 KiB
GLSL
86 lines
No EOL
2.4 KiB
GLSL
#version 450
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// PN patch data
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struct PnPatch
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{
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float b210;
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float b120;
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float b021;
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float b012;
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float b102;
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float b201;
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float b111;
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float n110;
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float n011;
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float n101;
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};
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// tessellation levels
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layout (binding = 0) uniform UBO
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{
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mat4 projection;
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mat4 model;
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float tessAlpha;
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float tessLevel;
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} ubo;
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layout(vertices=3) out;
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layout(location = 0) in vec3 inNormal[];
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layout(location = 1) in vec2 inUV[];
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layout(location = 0) out vec3 outNormal[3];
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layout(location = 3) out vec2 outUV[3];
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layout(location = 6) out PnPatch outPatch[3];
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float wij(int i, int j)
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{
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return dot(gl_in[j].gl_Position.xyz - gl_in[i].gl_Position.xyz, inNormal[i]);
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}
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float vij(int i, int j)
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{
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vec3 Pj_minus_Pi = gl_in[j].gl_Position.xyz
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- gl_in[i].gl_Position.xyz;
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vec3 Ni_plus_Nj = inNormal[i]+inNormal[j];
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return 2.0*dot(Pj_minus_Pi, Ni_plus_Nj)/dot(Pj_minus_Pi, Pj_minus_Pi);
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}
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void main()
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{
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// get data
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gl_out[gl_InvocationID].gl_Position = gl_in[gl_InvocationID].gl_Position;
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outNormal[gl_InvocationID] = inNormal[gl_InvocationID];
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outUV[gl_InvocationID] = inUV[gl_InvocationID];
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// set base
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float P0 = gl_in[0].gl_Position[gl_InvocationID];
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float P1 = gl_in[1].gl_Position[gl_InvocationID];
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float P2 = gl_in[2].gl_Position[gl_InvocationID];
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float N0 = inNormal[0][gl_InvocationID];
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float N1 = inNormal[1][gl_InvocationID];
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float N2 = inNormal[2][gl_InvocationID];
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// compute control points
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outPatch[gl_InvocationID].b210 = (2.0*P0 + P1 - wij(0,1)*N0)/3.0;
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outPatch[gl_InvocationID].b120 = (2.0*P1 + P0 - wij(1,0)*N1)/3.0;
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outPatch[gl_InvocationID].b021 = (2.0*P1 + P2 - wij(1,2)*N1)/3.0;
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outPatch[gl_InvocationID].b012 = (2.0*P2 + P1 - wij(2,1)*N2)/3.0;
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outPatch[gl_InvocationID].b102 = (2.0*P2 + P0 - wij(2,0)*N2)/3.0;
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outPatch[gl_InvocationID].b201 = (2.0*P0 + P2 - wij(0,2)*N0)/3.0;
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float E = ( outPatch[gl_InvocationID].b210
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+ outPatch[gl_InvocationID].b120
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+ outPatch[gl_InvocationID].b021
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+ outPatch[gl_InvocationID].b012
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+ outPatch[gl_InvocationID].b102
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+ outPatch[gl_InvocationID].b201 ) / 6.0;
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float V = (P0 + P1 + P2)/3.0;
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outPatch[gl_InvocationID].b111 = E + (E - V)*0.5;
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outPatch[gl_InvocationID].n110 = N0+N1-vij(0,1)*(P1-P0);
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outPatch[gl_InvocationID].n011 = N1+N2-vij(1,2)*(P2-P1);
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outPatch[gl_InvocationID].n101 = N2+N0-vij(2,0)*(P0-P2);
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// set tess levels
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gl_TessLevelOuter[gl_InvocationID] = ubo.tessLevel;
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gl_TessLevelInner[0] = ubo.tessLevel;
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} |