use per-mesh color instead of per-vertex

src/mesh_view.cpp

@@ -11,15 +11,12 @@ MeshView::MeshView(const MeshProcessor &mesh_processor, QOpenGLShaderProgram &pr
 	 n_vertices(mesh_processor.mesh.n_vertices()),
 	 mesh_processor(mesh_processor) {
 	const MyMesh &mesh = mesh_processor.mesh;
-    QVector<GLfloat> vertices(n_vertices * 6);
+    QVector<GLfloat> vertices(n_vertices * 3);
 	size_t i = 0;
 	for (const VertexHandle it : mesh.vertices()) {
-		vertices[6*i + 0] = mesh.point(it)[0];
-		vertices[6*i + 1] = mesh.point(it)[1];
-		vertices[6*i + 2] = mesh.point(it)[2];
-		vertices[6*i + 3] = mesh.color.red();
-		vertices[6*i + 4] = mesh.color.green();
-		vertices[6*i + 5] = mesh.color.blue();
+		vertices[3*i + 0] = mesh.point(it)[0];
+		vertices[3*i + 1] = mesh.point(it)[1];
+		vertices[3*i + 2] = mesh.point(it)[2];
 		i++;
 	}
 	QVector<GLuint> indices(n_faces * 3);
@@ -39,15 +36,13 @@ MeshView::MeshView(const MeshProcessor &mesh_processor, QOpenGLShaderProgram &pr
 		vertex_buffer.create();
 		vertex_buffer.bind();
 		vertex_buffer.setUsagePattern(QOpenGLBuffer::StreamDraw);
-		vertex_buffer.allocate(vertices.constData(), n_vertices * 6 * sizeof (GLfloat));
+		vertex_buffer.allocate(vertices.constData(), n_vertices * 3 * sizeof (GLfloat));
 		index_buffer.create();
 		index_buffer.bind();
 		index_buffer.setUsagePattern(QOpenGLBuffer::StreamDraw);
 		index_buffer.allocate(indices.constData(), n_faces * 3 * sizeof (GLuint));
-		program.setAttributeBuffer("pos", GL_FLOAT, 0, 3, 6 * sizeof (GLfloat));
+		program.setAttributeBuffer("pos", GL_FLOAT, 0, 3);
 		program.enableAttributeArray("pos");
-		program.setAttributeBuffer("col", GL_FLOAT, 3 * sizeof (GLfloat), 3, 6 * sizeof (GLfloat));
-		program.enableAttributeArray("col");
 	}
 }
 
@@ -70,6 +65,7 @@ void MeshView::paint(QOpenGLShaderProgram &program) {
 		qFatal("Failed to get OpenGL 2.1 functions");
 
 	program.setUniformValue("model", mesh.transform);
+	program.setUniformValue("col", mesh.color.redF(), mesh.color.greenF(), mesh.color.blueF());
 
 	{QOpenGLVertexArrayObject::Binder binder(&vao);
 		/* Mesh */

src/my_mesh.h

@@ -19,7 +19,7 @@ struct MyTraits : public OpenMesh::DefaultTraits {
 class MyMesh : public OpenMesh::TriMesh_ArrayKernelT<MyTraits> {
 public:
 	QMatrix4x4 transform;
-	QColor color;
+	QColor color = {127, 127, 127};
 };
 
 typedef MyMesh::FaceHandle FaceHandle;

src/shader.frag

@@ -1,5 +1,4 @@
-varying vec3 frag_col;
-
+uniform vec3 col;
 uniform vec3 wf_col;
 uniform bool wireframe;
 uniform float alpha;
@@ -8,6 +7,5 @@ void main() {
 	if (wireframe)
 		gl_FragColor = vec4(wf_col, alpha);
 	else
-		// gl_FragColor = vec4(frag_col, alpha);
-		gl_FragColor = vec4(.5, .5, .5, alpha);
+		gl_FragColor = vec4(col, alpha);
 }

src/shader.vert

@@ -1,7 +1,4 @@
 attribute vec3 pos;
-attribute vec3 col;
-
-varying vec3 frag_col;
 
 uniform mat4 proj;
 uniform mat4 view;
@@ -9,5 +6,4 @@ uniform mat4 model;
 
 void main() {
 	gl_Position = proj * view * model * vec4(pos, 1.0);
-	frag_col = col;
 }