Add shader for neighbor calculation

QTProject/resources.qrc

@@ -7,6 +7,7 @@
         <file>subdivide.vert</file>
         <file>subdivision-copy.compute</file>
         <file>subdivision-edge.compute</file>
+        <file>subdivision-neighbors.compute</file>
         <file>subdivision-vertex.compute</file>
         <file>subdivideRegular.tcs</file>
         <file>subdivideRegular.tes</file>

QTProject/subdivision-neighbors.compute

+#version 430 core
+
+layout  (local_size_x  = 1, local_size_y = 1)  in;
+
+struct Vertex {
+    vec3 pos;
+    vec3 norm;
+    vec2 uv;
+};
+
+layout(std430, binding=0) buffer Vertices {
+    Vertex vb[];
+};
+
+layout(std430, binding=1) buffer Index {
+    unsigned int ib[];
+};
+
+layout(std430, binding=2) buffer Offset {
+    unsigned int offset_in;
+    unsigned int offset_search;
+};
+
+layout(std430, binding=3) buffer Output {
+    int neighbors[][3];
+};
+
+int shared_edge(vec3 u, vec3 v, vec3 w, vec3 a, vec3 b, vec3 c) {
+    if (u == a && v == c) {
+        return 0;
+    } else if (u == a && w == b) {
+        return 2;
+    } else if (v == a && w == c) {
+        return 1;
+    }
+    return -1;
+}
+
+void main() {
+    if (3 * (gl_GlobalInvocationID.x + offset_in) + 2 >= ib.length()) {
+        return;
+    }
+
+    int found = 0;
+    found += (neighbors[gl_GlobalInvocationID.x + offset_in][0] > 0) ? 1 : 0;
+    found += (neighbors[gl_GlobalInvocationID.x + offset_in][1] > 0) ? 1 : 0;
+    found += (neighbors[gl_GlobalInvocationID.x + offset_in][2] > 0) ? 1 : 0;
+
+    vec3 u = vb[ib[3 * (gl_GlobalInvocationID.x + offset_in) + 0]].pos;
+    vec3 v = vb[ib[3 * (gl_GlobalInvocationID.x + offset_in) + 1]].pos;
+    vec3 w = vb[ib[3 * (gl_GlobalInvocationID.x + offset_in) + 2]].pos;
+
+    for (int i = 0; found < 3 && i < 128 && (3 * gl_GlobalInvocationID.y + offset_search + gl_NumWorkGroups.y * i) + 2 < ib.length(); i++) {
+        vec3 a = vb[ib[3 * (gl_GlobalInvocationID.y + offset_search + gl_NumWorkGroups.y * i) + 0]].pos;
+        vec3 b = vb[ib[3 * (gl_GlobalInvocationID.y + offset_search + gl_NumWorkGroups.y * i) + 1]].pos;
+        vec3 c = vb[ib[3 * (gl_GlobalInvocationID.y + offset_search + gl_NumWorkGroups.y * i) + 2]].pos;
+
+        int edge;
+        edge = shared_edge(u, v, w, a, b, c);
+        if (edge < 0) {
+            edge = shared_edge(u, v, w, b, c, a);
+        }
+        if (edge < 0) {
+            edge = shared_edge(u, v, w, c, a, b);
+        }
+        if (edge >= 0) {
+            neighbors[gl_GlobalInvocationID.x + offset_in][edge] = int(gl_GlobalInvocationID.y + offset_search + gl_NumWorkGroups.y * i);
+            found++;
+        }
+    }
+}

QTProject/subdivision.cpp

@@ -10,6 +10,7 @@ Subdivision::Subdivision(QOpenGLFunctions_4_3_Core *f)
 
 Subdivision::~Subdivision()
 {
+    delete neighborsShader;
     delete copyShader;
     delete edgeShader;
     delete vertexShader;
@@ -22,7 +23,10 @@ QString Subdivision::formatTimeMeasurement(int time){
 }
 
 void Subdivision::init() {
-    QString source = QLatin1String(":/subdivision-copy.compute");
+    QString source = QLatin1String(":/subdivision-neighbors.compute");
+    neighborsShader = initComputeShaderProgram(source);
+
+    source = QLatin1String(":/subdivision-copy.compute");
     copyShader = initComputeShaderProgram(source);
 
     source = QLatin1String(":/subdivision-edge.compute");

QTProject/subdivision.h

@@ -51,6 +51,7 @@ private:
     QString formatTimeMeasurement(int time);
 
     QOpenGLFunctions_4_3_Core *f;
+    QOpenGLShaderProgram *neighborsShader;
     QOpenGLShaderProgram *copyShader;
     QOpenGLShaderProgram *edgeShader;
     QOpenGLShaderProgram *vertexShader;