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/* This shader is only used for intel GPU where the Geom shader is faster
* than doing everything thrice in the vertex shader. */
layout(triangles) in;
#ifdef SELECT_EDGES
layout(line_strip, max_vertices = 6) out;
#else
layout(triangle_strip, max_vertices = 3) out;
#endif
uniform vec2 wireStepParam;
in vec2 ssPos[];
in float facingOut[];
#ifndef SELECT_EDGES
flat out vec3 ssVec0;
flat out vec3 ssVec1;
flat out vec3 ssVec2;
out float facing;
#endif
#ifdef LIGHT_EDGES
in vec3 obPos[];
in vec3 vNor[];
in float forceEdge[];
# ifndef SELECT_EDGES
flat out vec3 edgeSharpness;
# endif
#endif
#define NO_EDGE vec3(10000.0);
/* TODO(fclem) remove code duplication. */
vec3 compute_vec(vec2 v0, vec2 v1)
{
vec2 v = normalize(v1 - v0);
v = vec2(-v.y, v.x);
return vec3(v, -dot(v, v0));
}
vec3 get_edge_normal(vec3 n1, vec3 n2, vec3 edge)
{
edge = normalize(edge);
vec3 n = n1 + n2;
float p = dot(edge, n);
return normalize(n - p * edge);
}
float get_edge_sharpness(vec3 fnor, vec3 vnor)
{
float sharpness = abs(dot(fnor, vnor));
return smoothstep(wireStepParam.x, wireStepParam.y, sharpness);
}
void main(void)
{
vec3 facings = vec3(facingOut[0], facingOut[1], facingOut[2]);
bvec3 do_edge = greaterThan(abs(facings), vec3(1.0));
facings = fract(facings) - clamp(-sign(facings), 0.0, 1.0);
#ifndef SELECT_EDGES
ssVec0 = do_edge.x ? compute_vec(ssPos[0], ssPos[1]) : NO_EDGE;
ssVec1 = do_edge.y ? compute_vec(ssPos[1], ssPos[2]) : NO_EDGE;
ssVec2 = do_edge.z ? compute_vec(ssPos[2], ssPos[0]) : NO_EDGE;
#else
vec3 edgeSharpness;
#endif
#ifdef LIGHT_EDGES
vec3 edges[3];
edges[0] = obPos[1] - obPos[0];
edges[1] = obPos[2] - obPos[1];
edges[2] = obPos[0] - obPos[2];
vec3 fnor = normalize(cross(edges[0], -edges[2]));
edgeSharpness.x = get_edge_sharpness(fnor, get_edge_normal(vNor[0], vNor[1], edges[0]));
edgeSharpness.y = get_edge_sharpness(fnor, get_edge_normal(vNor[1], vNor[2], edges[1]));
edgeSharpness.z = get_edge_sharpness(fnor, get_edge_normal(vNor[2], vNor[0], edges[2]));
edgeSharpness.x = (forceEdge[0] == 1.0) ? 1.0 : edgeSharpness.x;
edgeSharpness.y = (forceEdge[1] == 1.0) ? 1.0 : edgeSharpness.y;
edgeSharpness.z = (forceEdge[2] == 1.0) ? 1.0 : edgeSharpness.z;
#endif
#ifdef SELECT_EDGES
const float edge_select_threshold = 0.3;
if (edgeSharpness.x > edge_select_threshold) {
gl_Position = gl_in[0].gl_Position;
EmitVertex();
gl_Position = gl_in[1].gl_Position;
EmitVertex();
EndPrimitive();
}
if (edgeSharpness.y > edge_select_threshold) {
gl_Position = gl_in[1].gl_Position;
EmitVertex();
gl_Position = gl_in[2].gl_Position;
EmitVertex();
EndPrimitive();
}
if (edgeSharpness.z > edge_select_threshold) {
gl_Position = gl_in[2].gl_Position;
EmitVertex();
gl_Position = gl_in[0].gl_Position;
EmitVertex();
EndPrimitive();
}
#else
gl_Position = gl_in[0].gl_Position;
facing = facings.x;
EmitVertex();
gl_Position = gl_in[1].gl_Position;
facing = facings.y;
EmitVertex();
gl_Position = gl_in[2].gl_Position;
facing = facings.z;
EmitVertex();
EndPrimitive();
#endif
}
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