Draw Quad with custom shader DrawCallback about imgui HOT 9 CLOSED

Yes indeed It need extra for to add more data etc.
https://github.com/soufianekhiat/ImPlatform/blob/main/ImPlatform/ImPlatform.cpp#L1173
If I need another Vertex Format I'll need to create my own data struct for draw call, and by pass the ImDrawList pass.

Interpretation of that available on ImPlatform:
https://github.com/soufianekhiat/ImPlatform/blob/main/ImPlatformDemo/main.cpp#L106
https://github.com/soufianekhiat/ImPlatform/blob/main/ImPlatformDemo/main.cpp#L201
https://github.com/soufianekhiat/ImPlatform/blob/main/ImPlatformDemo/main.cpp#L201
Hidden under 'IM_SUPPORT_CUSTOM_SHADER' while I don't support "enough" backend.

from imgui.

This code is not working, and produce a gpu hang.

I'm not sure how we can help, it's seems likely a problem with your use of DX11.

It will be a simpler (no brainer) to have a trivial pixel shader with 4 vertices instead.

It doesn't seem simpler to me IMHO because you are going to need lots of shader variants.
But maybe you can find a way to let dear imgui generate the mesh and only act on the shader.

from imgui.

I'm not sure how we can help, it's seems likely a problem with your use of DX11.

If it's dx11 problem I can work on it. I never saw a proper usage of draw callback I'm not sure of the proper use.

It doesn't seem simpler to me IMHO because you are going to need lots of shader variants.
But maybe you can find a way to let dear imgui generate the mesh and only act on the shader.

True! More shader variant, but traded for more flexibility, for a simple linear gradient I need lot of vertices (based on where the gradient start end).
What do you mean by the last sentence?
Current I had to tesselate the geometry
https://github.com/soufianekhiat/DearWidgets/blob/rework/src/api/dear_widgets.cpp#L2078
From a simple geometry:
https://github.com/soufianekhiat/DearWidgets/blob/rework/src/api/dear_widgets.cpp#L2355
To have a sense of a simple linear gradient:
https://github.com/soufianekhiat/DearWidgets/blob/rework/src/api/dear_widgets.cpp#L2439

from imgui.

Here an illustration of the problem:

from imgui.

You should probably use RenderDoc or another gpu debugger to understand why your code is crashing.

What do you mean by the last sentence?

DrawQuadWithCustomShader output a simple quad which can already be output by ImDrawList, so maybe you can simply your callback logic to set shader + some uniforms for your shader, and not attempt to create/bind buffers.

AddCallback(bind your shader and data)
AddRectFilled()
AddCallback(ImDrawCallback_ResetRenderState)

from imgui.

[Fixed]

ImGui::Begin( "Custom Shader" );
	ImDrawList* draw = ImGui::GetWindowDrawList();
	ImVec2 cur = ImGui::GetCursorScreenPos();
	draw->AddCallback( &DrawCustomShaderQuad, &shader );
	ImRect bb( cur, cur + ImGui::GetContentRegionAvail() );
	draw->AddImageQuad( img, bb.GetBL(), bb.GetBR(), bb.GetTR(), bb.GetTL(), ImVec2( 0, 0 ), ImVec2( 1, 0 ), ImVec2( 1, 1 ), ImVec2( 0, 1 ), IM_COL32_WHITE );
	draw->AddCallback( ImDrawCallback_ResetRenderState, NULL );
ImGui::End();

Your second recommendation is much simple, it simplify the memory management etc. And rely on unique Vertex Buffer.

void DrawCustomShaderQuad( const ImDrawList* parent_list, const ImDrawCmd* cmd )
{
	ImPlatform::ImShader* shaders = ( ImPlatform::ImShader* )cmd->UserCallbackData;
	ImGui_ImplDX11_Data* bd = ImGui_ImplDX11_GetBackendData();
	ID3D11DeviceContext* ctx = bd->pd3dDeviceContext;
	ctx->PSSetShader( ( ID3D11PixelShader* )( shaders->ps ), nullptr, 0 );
}

from imgui.

I guess you’ll need to pass some extra data to your shader but that’s the general idea yes (as long as the vertex format used by ImDrawList is sufficient for you).

from imgui.

Sidenote to have it portable for GLSL and GLSL I prefix all shaders with:
https://github.com/soufianekhiat/ImPlatform/blob/main/ImPlatform/ImPlatform.cpp#L1016

from imgui.

Good to hear. Do you need anything else on my end or can we close this?

from imgui.