draw a fullscreen triangle

[WdsPjm]

"I want to draw a fullscreen triangle, and I referred to this resource: https://www.saschawillems.de/blog/2016/08/13/vulkan-tutorial-on-rendering-a-fullscreen-quad-without-buffers/. I modified the vertex and fragment shaders based on vsgdraw.cpp, but no image is being rendered, and there are no error messages from the Vulkan validation layers. I'm unsure where to look for the problem.

[WdsPjm]

The main issue was that the depth test wasn't disabled. Here is my solution, hoping it might help others

                                                                        #version 450
                                                                        out gl_PerVertex { vec4 gl_Position; };
                                                                        void main() { 
                                                                         vec2  tmpUv = vec2((gl_VertexIndex << 1) & 2, gl_VertexIndex & 2);
                                                                         gl_Position = vec4(tmpUv * 2.0f - 1.0f, 0.0f, 1.0f);    }



                                                                            #version 450
                                                                            layout(location = 0) out vec4 color;
                                                                            void main() { 
                                                                            color = vec4(0.0,0.2,0.2, 1);   }

struct SetPipelineStates : public vsg::Visitor
{
void apply(vsg::DepthStencilState& ds) {
ds.depthTestEnable = VK_FALSE;
}
} sps;