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/* Solid Wirefram implementation
* Mike Erwin, Clément Foucault */
/* This shader follows the principles of
* http://developer.download.nvidia.com/SDK/10/direct3d/Source/SolidWireframe/Doc/SolidWireframe.pdf */
uniform float faceAlphaMod;
flat in vec3 edgesCrease;
flat in vec3 edgesBweight;
flat in ivec3 flag;
flat in vec4 faceColor;
flat in int clipCase;
#ifdef VERTEX_SELECTION
in vec3 vertexColor;
#endif
/* We use a vec4[2] interface to pass edge data
* (without fragmenting memory accesses)
*
* There are 2 cases :
*
* - Simple case : geometry shader return edge distances
* in the first 2 components of the first vec4.
* This needs noperspective interpolation.
* The rest is filled with vertex screen positions.
* eData1.zw actually contain v2
* eData2.xy actually contain v1
* eData2.zw actually contain v0
*
* - Hard case : two 2d edge corner are described by each
* vec4 as origin and direction. This is constant over
* the triangle and use to detect the correct case. */
noperspective in vec4 eData1;
flat in vec4 eData2;
out vec4 FragColor;
#define EDGE_EXISTS (1 << 0)
#define EDGE_ACTIVE (1 << 1)
#define EDGE_SELECTED (1 << 2)
#define EDGE_SEAM (1 << 3)
#define EDGE_SHARP (1 << 4)
/* Vertex flag is shifted and combined with the edge flag */
#define VERTEX_ACTIVE (1 << (0 + 8))
#define VERTEX_SELECTED (1 << (1 + 8))
#define FACE_ACTIVE (1 << (2 + 8))
/* Style Parameters in pixel */
/* Array to retrieve vert/edge indices */
const ivec3 clipEdgeIdx[6] = ivec3[6](
ivec3(1, 0, 2),
ivec3(2, 0, 1),
ivec3(2, 1, 0),
ivec3(2, 1, 0),
ivec3(2, 0, 1),
ivec3(1, 0, 2)
);
const ivec3 clipPointIdx[6] = ivec3[6](
ivec3(0, 1, 2),
ivec3(0, 2, 1),
ivec3(0, 2, 1),
ivec3(1, 2, 0),
ivec3(1, 2, 0),
ivec3(2, 1, 0)
);
const mat4 stipple_matrix = mat4(
vec4(1.0, 0.0, 0.0, 0.0),
vec4(0.0, 0.0, 0.0, 0.0),
vec4(0.0, 0.0, 1.0, 0.0),
vec4(0.0, 0.0, 0.0, 0.0)
);
void colorDist(vec4 color, float dist)
{
FragColor = (dist < 0) ? color : FragColor;
}
float distToEdge(vec2 o, vec2 dir)
{
vec2 af = gl_FragCoord.xy - o;
float daf = dot(dir, af);
return sqrt(abs(dot(af, af) - daf * daf));
}
void main()
{
vec3 e, p;
/* Step 1 : Computing Distances */
if (clipCase == 0) {
e.xy = eData1.xy;
/* computing missing distance */
vec2 dir = normalize(eData2.zw - eData2.xy);
e.z = distToEdge(eData2.zw, dir);
p.x = distance(eData2.zw, gl_FragCoord.xy);
p.y = distance(eData2.xy, gl_FragCoord.xy);
p.z = distance(eData1.zw, gl_FragCoord.xy);
}
else {
ivec3 eidxs = clipEdgeIdx[clipCase - 1];
ivec3 pidxs = clipPointIdx[clipCase - 1];
e[eidxs.x] = distToEdge(eData1.xy, eData1.zw);
e[eidxs.y] = distToEdge(eData2.xy, eData2.zw);
/* Three edges visible cases */
if (clipCase == 1 || clipCase == 2 || clipCase == 4) {
e[eidxs.z] = distToEdge(eData1.xy, normalize(eData2.xy - eData1.xy));
p[pidxs.y] = distance(eData2.xy, gl_FragCoord.xy);
}
else {
e[eidxs.z] = 1e10; /* off screen */
p[pidxs.y] = 1e10; /* off screen */
}
p[pidxs.x] = distance(eData1.xy, gl_FragCoord.xy);
p[pidxs.z] = 1e10; /* off screen */
}
/* Step 2 : coloring (order dependant) */
/* First */
FragColor = faceColor;
if ((flag[0] & FACE_ACTIVE) != 0) {
int x = int(gl_FragCoord.x) & 0x3; /* mod 4 */
int y = int(gl_FragCoord.y) & 0x3; /* mod 4 */
FragColor *= stipple_matrix[x][y];
}
else {
FragColor.a *= faceAlphaMod;
}
/* Edges */
for (int v = 0; v < 3; ++v) {
if ((flag[v] & EDGE_EXISTS) != 0) {
float largeEdge = e[v] - sizeEdge * 2.0;
float innerEdge = e[v] - sizeEdge;
if ((flag[v] & EDGE_SEAM) != 0)
colorDist(colorEdgeSeam, largeEdge);
else if (edgesBweight[v] > 0.0)
colorDist(vec4(colorEdgeBWeight.rgb, edgesBweight[v]), largeEdge);
else if (edgesCrease[v] > 0.0)
colorDist(vec4(colorEdgeCrease.rgb, edgesCrease[v]), largeEdge);
else if ((flag[v] & EDGE_SHARP) != 0)
colorDist(colorEdgeSharp, largeEdge);
#ifndef VERTEX_SELECTION
else
colorDist(colorWireEdit, innerEdge);
if ((flag[v] & EDGE_ACTIVE) != 0)
colorDist(vec4(colorEditMeshActive.xyz, 1.0), innerEdge);
else if ((flag[v] & EDGE_SELECTED) != 0)
colorDist(colorEdgeSelect, innerEdge);
#else
colorDist(vec4(vertexColor, 1.0), innerEdge);
#endif
}
}
/* Points */
#ifdef VERTEX_SELECTION
for (int v = 0; v < 3; ++v) {
float size = p[v] - sizeVertex;
if ((flag[v] & VERTEX_ACTIVE) != 0)
colorDist(vec4(colorEditMeshActive.xyz, 1.0), size);
else if ((flag[v] & VERTEX_SELECTED) != 0)
colorDist(colorVertexSelect, size);
else
colorDist(colorVertex, size);
}
#endif
/* don't write depth if not opaque */
if (FragColor.a == 0.0) discard;
}
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