feat: hard face normals per vertex

src/Gui/Viewport/GLMesh.cpp

@@ -86,25 +86,52 @@ void GLMesh::setPosBuffer(enzo::geo::Geometry& geometry)
     std::vector<int> vertexCounts = vertexCountHandle.getAllValues();
 
     unsigned int vertexCount = 0;
+    unsigned int primStartVert = 0;
 
     for (int primIndx=0; primIndx<vertexCounts.size(); ++primIndx)
     {
-        for(int i=0; i< vertexCounts[primIndx]; ++i)
+        auto faceIndex = primIndx;
+        int faceVertCnt = vertexCounts[primIndx];
+
+        enzo::bt::Vector3 n;
+
+        // compute normal
+        if(faceVertCnt>=3)
+        {
+            const unsigned v0 = primStartVert;
+            const unsigned v1 = primStartVert + 1;
+            const unsigned v2 = primStartVert + 2;
+
+            const enzo::bt::Vector3 pos1 = pointPositions[vertexPointIndices[v0]];
+            const enzo::bt::Vector3 pos2 = pointPositions[vertexPointIndices[v1]];
+            const enzo::bt::Vector3 pos3 = pointPositions[vertexPointIndices[v2]];
+
+            const enzo::bt::Vector3 tang1 = (pos2-pos1).normalized();
+            const enzo::bt::Vector3 tang2 = (pos3-pos1).normalized();
+
+            n = tang1.cross(tang2);
+        }
+
+        for(int i=0; i< faceVertCnt; ++i)
         {
             unsigned int pointIndex = vertexPointIndices[vertexCount];
             enzo::bt::Vector3& p = pointPositions[pointIndex];
+
+                 
+
             IC(vertexCount, pointIndex);
             IC(p.x(), p.y(), p.z());
             vertices.push_back({
                 { p.x(),
                   p.y(),
                   p.z()},
-                { p.x(),
-                  p.y(),
-                  p.z()}
+                { n.x(),
+                  n.y(),
+                  n.z()}
             });
             ++vertexCount;
         }
+        primStartVert+=faceVertCnt;
 
     }
 
@@ -126,7 +153,7 @@ void GLMesh::setIndexBuffer(std::vector<int> pointIndices, std::vector<int> prim
         int primVertexCount = primVertexCounts[primNum];
 
 
-        for(size_t i=0; i<primVertexCount-1; ++i)
+        for(size_t i=1; i<primVertexCount-1; ++i)
         {
             indexData.push_back(startVert);
             indexData.push_back(startVert+i);

src/Gui/Viewport/ViewportGLWidget.cpp

@@ -85,22 +85,26 @@ void ViewportGLWidget::initializeGL()
     #version 330 core
     in vec3 Normal;
 
-    out vec4 color;
+    out vec4 FragColor;
 
     float remap(float value, float inMin, float inMax, float outMin, float outMax)
     {
         return outMin + (outMax - outMin) * (value - inMin) / (inMax - inMin);
     }
 
+    vec3 remap(vec3 value, vec3 inMin, vec3 inMax, vec3 outMin, vec3 outMax)
+    {
+        return outMin + (outMax - outMin) * (value - inMin) / (inMax - inMin);
+    }
+
     void main()
     {
         // FragColor = vec4(1.0f, 0.5f, 0.2f, 1.0f);
         vec3 lightDir = normalize(vec3(1.0,1.0,1.0));
         float brightness = remap(dot(Normal, lightDir), -1, 1, 0.5, 1);
-        color = vec4(vec3(brightness), 1.0f);
-
-        color = vec4(Normal, 1.0f);
+        vec4 Color = vec4(remap(Normal, vec3(-1), vec3(1), vec3(0), vec3(1)), 1.0f);
 
+        FragColor = Color;
     }
     )";
     GLuint fragmentShader = glCreateShader(GL_FRAGMENT_SHADER);