Add provoking vertex to caps, flip the flag around

Common/GPU/D3D11/thin3d_d3d11.cpp

@@ -281,6 +281,8 @@ D3D11DrawContext::D3D11DrawContext(ID3D11Device *device, ID3D11DeviceContext *de
 	caps_.blendMinMaxSupported = true;
 	caps_.multiSampleLevelsMask = 1;   // More could be supported with some work.
 
+	caps_.provokingVertexLast = false;  // D3D has it first, unfortunately. (and no way to change it).
+
 	caps_.presentInstantModeChange = true;
 	caps_.presentMaxInterval = 4;
 	caps_.presentModesSupported = PresentMode::FIFO | PresentMode::IMMEDIATE;

Common/GPU/D3D9/thin3d_d3d9.cpp

@@ -786,6 +786,8 @@ D3D9Context::D3D9Context(IDirect3D9 *d3d, IDirect3D9Ex *d3dEx, int adapterId, ID
 	caps_.presentMaxInterval = 1;
 	caps_.presentModesSupported = PresentMode::FIFO;
 
+	caps_.provokingVertexLast = false;  // D3D has it first, unfortunately (and no way to change it).
+
 	if ((caps.RasterCaps & D3DPRASTERCAPS_ANISOTROPY) != 0 && caps.MaxAnisotropy > 1) {
 		caps_.anisoSupported = true;
 	}

Common/GPU/OpenGL/thin3d_gl.cpp

@@ -598,6 +598,9 @@ OpenGLContext::OpenGLContext(bool canChangeSwapInterval) : renderManager_(frameT
 	// GLES has no support for logic framebuffer operations. There doesn't even seem to exist any such extensions.
 	caps_.logicOpSupported = !gl_extensions.IsGLES;
 
+	// Always the case in GL (which is what we want for PSP flat shade).
+	caps_.provokingVertexLast = true;
+
 	// Interesting potential hack for emulating GL_DEPTH_CLAMP (use a separate varying, force depth in fragment shader):
 	// This will induce a performance penalty on many architectures though so a blanket enable of this
 	// is probably not a good idea.

Common/GPU/Vulkan/thin3d_vulkan.cpp

@@ -913,6 +913,9 @@ VKContext::VKContext(VulkanContext *vulkan, bool useRenderThread)
 	caps_.sampleRateShadingSupported = vulkan->GetDeviceFeatures().enabled.standard.sampleRateShading != 0;
 	caps_.textureSwizzleSupported = true;
 
+	// Note that it must also be enabled on the pipelines (which we do).
+	caps_.provokingVertexLast = vulkan->GetDeviceFeatures().enabled.provokingVertex.provokingVertexLast;
+
 	// Present mode stuff
 	caps_.presentMaxInterval = 1;
 	caps_.presentInstantModeChange = false;  // TODO: Fix this with some work in VulkanContext

Common/GPU/thin3d.h

@@ -612,7 +612,7 @@ struct DeviceCaps {
 	bool setMaxFrameLatencySupported;
 	bool textureSwizzleSupported;
 	bool requiresHalfPixelOffset;
-
+	bool provokingVertexLast;  // GL behavior, what the PSP does
 	bool verySlowShaderCompiler;
 
 	// From the other backends, we can detect if D3D9 support is known bad (like on Xe) and disable it.

GPU/Common/SoftwareTransformCommon.cpp

@@ -203,7 +203,7 @@ void SoftwareTransform::Transform(int prim, u32 vertType, const DecVtxFormat &de
 	}
 
 	int provokeIndOffset = 0;
-	if (params_.provokeFlatFirst) {
+	if (!params_.provokingVertexLast) {
 		provokeIndOffset = ColorIndexOffset(prim, gstate.getShadeMode(), gstate.isModeClear());
 	}
 

GPU/Common/SoftwareTransformCommon.h

@@ -57,9 +57,9 @@ struct SoftwareTransformParams {
 	TextureCacheCommon *texCache;
 	bool allowClear;
 	bool allowSeparateAlphaClear;
-	bool provokeFlatFirst;
 	bool flippedY;
 	bool usesHalfZ;
+	bool provokingVertexLast;
 };
 
 class SoftwareTransform {

GPU/D3D11/DrawEngineD3D11.cpp

@@ -382,7 +382,7 @@ void DrawEngineD3D11::DoFlush() {
 		params.texCache = textureCache_;
 		params.allowClear = true;
 		params.allowSeparateAlphaClear = false;  // D3D11 doesn't support separate alpha clears
-		params.provokeFlatFirst = true;
+		params.provokingVertexLast = false;
 		params.flippedY = false;
 		params.usesHalfZ = true;
 

GPU/Directx9/DrawEngineDX9.cpp

@@ -334,7 +334,7 @@ void DrawEngineDX9::DoFlush() {
 		params.texCache = textureCache_;
 		params.allowClear = true;
 		params.allowSeparateAlphaClear = false;
-		params.provokeFlatFirst = true;
+		params.provokingVertexLast = false;
 		params.flippedY = false;
 		params.usesHalfZ = true;
 

GPU/GLES/DrawEngineGLES.cpp

@@ -356,7 +356,7 @@ void DrawEngineGLES::DoFlush() {
 		params.texCache = textureCache_;
 		params.allowClear = true;  // Clear in OpenGL respects scissor rects, so we'll use it.
 		params.allowSeparateAlphaClear = true;
-		params.provokeFlatFirst = false;
+		params.provokingVertexLast = true;
 		params.flippedY = framebufferManager_->UseBufferedRendering();
 		params.usesHalfZ = false;
 

GPU/Vulkan/DrawEngineVulkan.cpp

@@ -407,9 +407,9 @@ void DrawEngineVulkan::DoFlush() {
 		params.allowSeparateAlphaClear = false;
 		if (renderManager->GetVulkanContext()->GetDeviceFeatures().enabled.provokingVertex.provokingVertexLast) {
 			// We can get the OpenGL behavior, no need for workarounds.
-			params.provokeFlatFirst = false;
+			params.provokingVertexLast = true;
 		} else {
-			params.provokeFlatFirst = true;
+			params.provokingVertexLast = false;
 		}
 		params.flippedY = true;
 		params.usesHalfZ = true;