RHI: Add Compute Pipeline abstraction with D3D12 and OpenGL support

- Add SetComputeShader/GetComputeShader/HasComputeShader to RHIPipelineState
- Add m_computePipelineState for D3D12 compute PSO
- Add m_computeProgram/m_computeShader for OpenGL
- Fix OpenGLCommandList::DispatchCompute bug (was ignoring x,y,z params)
- Fix OpenGLShader::GetID usage in OpenGLPipelineState
- Mark Priority 8 as completed in RHI_Design_Issues.md

engine/src/RHI/D3D12/D3D12PipelineState.cpp

@@ -1,4 +1,5 @@
 #include "XCEngine/RHI/D3D12/D3D12PipelineState.h"
+#include "XCEngine/RHI/D3D12/D3D12Shader.h"
 #include <cstring>
 
 namespace XCEngine {
@@ -121,8 +122,19 @@ void D3D12PipelineState::SetShaderBytecodes(const D3D12_SHADER_BYTECODE& vs, con
     m_gsBytecode = gs;
 }
 
+void D3D12PipelineState::SetComputeShader(RHIShader* shader) {
+    m_computeShader = shader;
+}
+
+void D3D12PipelineState::SetComputeShaderBytecodes(const D3D12_SHADER_BYTECODE& cs) {
+    m_csBytecode = cs;
+}
+
 bool D3D12PipelineState::Finalize() {
     if (m_finalized) return true;
+    if (HasComputeShader()) {
+        return CreateD3D12ComputePSO();
+    }
     return CreateD3D12PSO();
 }
 
@@ -190,8 +202,27 @@ bool D3D12PipelineState::CreateD3D12PSO() {
     return true;
 }
 
+bool D3D12PipelineState::CreateD3D12ComputePSO() {
+    if (!m_csBytecode.pShaderBytecode || !m_csBytecode.BytecodeLength) {
+        return false;
+    }
+
+    D3D12_COMPUTE_PIPELINE_STATE_DESC desc = {};
+    desc.pRootSignature = m_rootSignature;
+    desc.CS = m_csBytecode;
+
+    HRESULT hr = m_device->CreateComputePipelineState(&desc, IID_PPV_ARGS(&m_computePipelineState));
+    if (FAILED(hr)) {
+        return false;
+    }
+
+    m_finalized = true;
+    return true;
+}
+
 void D3D12PipelineState::Shutdown() {
     m_pipelineState.Reset();
+    m_computePipelineState.Reset();
     m_finalized = false;
 }