Backends: DX11: Expose vertex constant buffer in ImGui_ImplDX11_RenderState.
DX9 and DX12 users can already alter the projection matrix (in undocumented ways, but possible)
diff --git a/backends/imgui_impl_dx11.cpp b/backends/imgui_impl_dx11.cpp
index a2c67ec..bbd1633 100644
--- a/backends/imgui_impl_dx11.cpp
+++ b/backends/imgui_impl_dx11.cpp
@@ -16,6 +16,7 @@
// CHANGELOG
// (minor and older changes stripped away, please see git history for details)
+// 2025-01-06: DirectX11: Expose VertexConstantBuffer in ImGui_ImplDX11_RenderState. Reset projection matrix in ImDrawCallback_ResetRenderState handler.
// 2024-10-07: DirectX11: Changed default texture sampler to Clamp instead of Repeat/Wrap.
// 2024-10-07: DirectX11: Expose selected render state in ImGui_ImplDX11_RenderState, which you can access in 'void* platform_io.Renderer_RenderState' during draw callbacks.
// 2022-10-11: Using 'nullptr' instead of 'NULL' as per our switch to C++11.
@@ -98,6 +99,27 @@
vp.TopLeftX = vp.TopLeftY = 0;
device_ctx->RSSetViewports(1, &vp);
+ // Setup orthographic projection matrix into our constant buffer
+ // Our visible imgui space lies from draw_data->DisplayPos (top left) to draw_data->DisplayPos+data_data->DisplaySize (bottom right). DisplayPos is (0,0) for single viewport apps.
+ D3D11_MAPPED_SUBRESOURCE mapped_resource;
+ if (device_ctx->Map(bd->pVertexConstantBuffer, 0, D3D11_MAP_WRITE_DISCARD, 0, &mapped_resource) == S_OK)
+ {
+ VERTEX_CONSTANT_BUFFER_DX11* constant_buffer = (VERTEX_CONSTANT_BUFFER_DX11*)mapped_resource.pData;
+ float L = draw_data->DisplayPos.x;
+ float R = draw_data->DisplayPos.x + draw_data->DisplaySize.x;
+ float T = draw_data->DisplayPos.y;
+ float B = draw_data->DisplayPos.y + draw_data->DisplaySize.y;
+ float mvp[4][4] =
+ {
+ { 2.0f/(R-L), 0.0f, 0.0f, 0.0f },
+ { 0.0f, 2.0f/(T-B), 0.0f, 0.0f },
+ { 0.0f, 0.0f, 0.5f, 0.0f },
+ { (R+L)/(L-R), (T+B)/(B-T), 0.5f, 1.0f },
+ };
+ memcpy(&constant_buffer->mvp, mvp, sizeof(mvp));
+ device_ctx->Unmap(bd->pVertexConstantBuffer, 0);
+ }
+
// Setup shader and vertex buffers
unsigned int stride = sizeof(ImDrawVert);
unsigned int offset = 0;
@@ -179,28 +201,6 @@
device->Unmap(bd->pVB, 0);
device->Unmap(bd->pIB, 0);
- // Setup orthographic projection matrix into our constant buffer
- // Our visible imgui space lies from draw_data->DisplayPos (top left) to draw_data->DisplayPos+data_data->DisplaySize (bottom right). DisplayPos is (0,0) for single viewport apps.
- {
- D3D11_MAPPED_SUBRESOURCE mapped_resource;
- if (device->Map(bd->pVertexConstantBuffer, 0, D3D11_MAP_WRITE_DISCARD, 0, &mapped_resource) != S_OK)
- return;
- VERTEX_CONSTANT_BUFFER_DX11* constant_buffer = (VERTEX_CONSTANT_BUFFER_DX11*)mapped_resource.pData;
- float L = draw_data->DisplayPos.x;
- float R = draw_data->DisplayPos.x + draw_data->DisplaySize.x;
- float T = draw_data->DisplayPos.y;
- float B = draw_data->DisplayPos.y + draw_data->DisplaySize.y;
- float mvp[4][4] =
- {
- { 2.0f/(R-L), 0.0f, 0.0f, 0.0f },
- { 0.0f, 2.0f/(T-B), 0.0f, 0.0f },
- { 0.0f, 0.0f, 0.5f, 0.0f },
- { (R+L)/(L-R), (T+B)/(B-T), 0.5f, 1.0f },
- };
- memcpy(&constant_buffer->mvp, mvp, sizeof(mvp));
- device->Unmap(bd->pVertexConstantBuffer, 0);
- }
-
// Backup DX state that will be modified to restore it afterwards (unfortunately this is very ugly looking and verbose. Close your eyes!)
struct BACKUP_DX11_STATE
{
@@ -255,6 +255,7 @@
render_state.Device = bd->pd3dDevice;
render_state.DeviceContext = bd->pd3dDeviceContext;
render_state.SamplerDefault = bd->pFontSampler;
+ render_state.VertexConstantBuffer = bd->pVertexConstantBuffer;
platform_io.Renderer_RenderState = &render_state;
// Render command lists
diff --git a/backends/imgui_impl_dx11.h b/backends/imgui_impl_dx11.h
index 69ae493..772c1b9 100644
--- a/backends/imgui_impl_dx11.h
+++ b/backends/imgui_impl_dx11.h
@@ -21,6 +21,7 @@
struct ID3D11Device;
struct ID3D11DeviceContext;
struct ID3D11SamplerState;
+struct ID3D11Buffer;
// Follow "Getting Started" link and check examples/ folder to learn about using backends!
IMGUI_IMPL_API bool ImGui_ImplDX11_Init(ID3D11Device* device, ID3D11DeviceContext* device_context);
@@ -40,6 +41,7 @@
ID3D11Device* Device;
ID3D11DeviceContext* DeviceContext;
ID3D11SamplerState* SamplerDefault;
+ ID3D11Buffer* VertexConstantBuffer;
};
#endif // #ifndef IMGUI_DISABLE
diff --git a/docs/CHANGELOG.txt b/docs/CHANGELOG.txt
index 412ddab..4500f5a 100644
--- a/docs/CHANGELOG.txt
+++ b/docs/CHANGELOG.txt
@@ -72,6 +72,8 @@
platforms not supporting VK_SURFACE_TRANSFORM_IDENTITY_BIT_KHR. (#8222) [@Zer0xFF]
- Backends: Vulkan: Added a few more ImGui_ImplVulkanH_XXX helper functions
primarily for the purpose of making our examples simpler.
+- Backends: DX11: Expose vertex constant buffer in ImGui_ImplDX11_RenderState.
+ Reset projection matrix in ImDrawCallback_ResetRenderState handlers. (#6969, #5834, #7468, #3590)
- Examples: Added Win32+Vulkan example for completeness. (#8180) [@jristic]
