// Our visible imgui space lies from draw_data->DisplayPos (top left) to draw_data->DisplayPos+data_data->DisplaySize (bottom right).
// Being agnostic of whether <d3dx9.h> or <DirectXMath.h> can be used, we aren't relying on D3DXMatrixIdentity()/D3DXMatrixOrthoOffCenterLH() or DirectX::XMMatrixIdentity()/DirectX::XMMatrixOrthographicOffCenterLH()
// Our visible imgui space lies from draw_data->DisplayPos (top left) to draw_data->DisplayPos+data_data->DisplaySize (bottom right).
// Being agnostic of whether <d3dx9.h> or <DirectXMath.h> can be used, we aren't relying on D3DXMatrixIdentity()/D3DXMatrixOrthoOffCenterLH() or DirectX::XMMatrixIdentity()/DirectX::XMMatrixOrthographicOffCenterLH()
// (this used to be set in io.RenderDrawListsFn and called by ImGui::Render(), but you can now call this directly from your main loop)
// Note that this implementation is little overcomplicated because we are saving/setting up/restoring every OpenGL state explicitly, in order to be able to run within any OpenGL engine that doesn't do so.
// (this used to be set in io.RenderDrawListsFn and called by ImGui::Render(), but you can now call this directly from your main loop)
// Note that this implementation is little overcomplicated because we are saving/setting up/restoring every OpenGL state explicitly, in order to be able to run within any OpenGL engine that doesn't do so.
// Setup render state: alpha-blending enabled, no face culling, no depth testing, scissor enabled, polygon fill
glEnable(GL_BLEND);
glBlendEquation(GL_FUNC_ADD);
glBlendFunc(GL_SRC_ALPHA,GL_ONE_MINUS_SRC_ALPHA);
glDisable(GL_CULL_FACE);
glDisable(GL_DEPTH_TEST);
glEnable(GL_SCISSOR_TEST);
#ifdef GL_POLYGON_MODE
glPolygonMode(GL_FRONT_AND_BACK,GL_FILL);
#endif
// Setup viewport, orthographic projection matrix
// Our visible imgui space lies from draw_data->DisplayPos (top left) to draw_data->DisplayPos+data_data->DisplaySize (bottom right). DisplayMin is typically (0,0) for single viewport apps.
// (this used to be set in io.RenderDrawListsFn and called by ImGui::Render(), but you can now call this directly from your main loop)
// Note that this implementation is little overcomplicated because we are saving/setting up/restoring every OpenGL state explicitly, in order to be able to run within any OpenGL engine that doesn't do so.
// Setup render state: alpha-blending enabled, no face culling, no depth testing, scissor enabled, polygon fill
glEnable(GL_BLEND);
glBlendEquation(GL_FUNC_ADD);
glBlendFunc(GL_SRC_ALPHA,GL_ONE_MINUS_SRC_ALPHA);
glDisable(GL_CULL_FACE);
glDisable(GL_DEPTH_TEST);
glEnable(GL_SCISSOR_TEST);
#ifdef GL_POLYGON_MODE
glPolygonMode(GL_FRONT_AND_BACK,GL_FILL);
#endif
// Setup viewport, orthographic projection matrix
// Our visible imgui space lies from draw_data->DisplayPos (top left) to draw_data->DisplayPos+data_data->DisplaySize (bottom right). DisplayMin is typically (0,0) for single viewport apps.
// Our visible imgui space lies from draw_data->DisplayPos (top left) to draw_data->DisplayPos+data_data->DisplaySize (bottom right). DisplayMin is typically (0,0) for single viewport apps.
// Our visible imgui space lies from draw_data->DisplayPos (top left) to draw_data->DisplayPos+data_data->DisplaySize (bottom right). DisplayMin is typically (0,0) for single viewport apps.
// NB: You most likely do NOT need to use draw callbacks just to create your own widget or customized UI rendering,
// you can poke into the draw list for that! Draw callback may be useful for example to: A) Change your GPU render state,
// B) render a complex 3D scene inside a UI element without an intermediate texture/render target, etc.
// you can poke into the draw list for that! Draw callback may be useful for example to:
// A) Change your GPU render state,
// B) render a complex 3D scene inside a UI element without an intermediate texture/render target, etc.
// The expected behavior from your rendering function is 'if (cmd.UserCallback != NULL) { cmd.UserCallback(parent_list, cmd); } else { RenderTriangles() }'
// Special Draw Callback value to request renderer back-end to reset the graphics/render state.
// The renderer back-end needs to handle this special value, otherwise it will crash trying to call a function at this address.
// This is useful for example if you submitted callbacks which you know have altered the render state and you want it to be restored.
// It is not done by default because they are many perfectly useful way of altering render state for imgui contents (e.g. changing shader/blending settings before an Image call).