Correct color of line vertices.

src/GraphicsDrawer.cpp

@@ -984,47 +984,59 @@ void GraphicsDrawer::drawDMATriangles(u32 _numVtx)
 	dropRenderState();
 }
 
-void GraphicsDrawer::_drawThickLine(u32 _v0, u32 _v1, float _width)
+static void correctLineVerticesColor(SPVertex _vertexBuf[2], SPVertex& _v0)
 {
+	auto copyColors = [](f32 const* src, f32* dst1, f32* dst2)
+	{
+		for (u32 i = 0; i < 4; ++i)
+			dst1[i] = dst2[i] = src[i];
+	};
+
+	auto convertNormalsToColors = [](f32 const* normals, f32* dst)
+	{
+		// Line3D* microcodes have no lighting code
+		// Original colors are stored in vertex normals, which need to be converted back to colors.
+		for (u32 i = 0; i < 3; ++i) {
+			f32 color = normals[i] * 0.5f;
+			if (color < 0.0f)
+				color += 1.0f;
+			dst[i] = color;
+		}
+	};
+
+	SPVertex & vtx1 = _vertexBuf[0];
+	SPVertex & vtx2 = _vertexBuf[1];
 	if ((gSP.geometryMode & G_LIGHTING) == 0) {
 		if ((gSP.geometryMode & G_SHADE) == 0) {
-			SPVertex & vtx1 = triangles.vertices[_v0];
-			vtx1.flat_r = gDP.primColor.r;
-			vtx1.flat_g = gDP.primColor.g;
-			vtx1.flat_b = gDP.primColor.b;
-			vtx1.flat_a = gDP.primColor.a;
-			SPVertex & vtx2 = triangles.vertices[_v1];
-			vtx2.flat_r = gDP.primColor.r;
-			vtx2.flat_g = gDP.primColor.g;
-			vtx2.flat_b = gDP.primColor.b;
-			vtx2.flat_a = gDP.primColor.a;
-		}
-		else if ((gSP.geometryMode & G_SHADING_SMOOTH) == 0) {
+			copyColors(&gDP.primColor.r, &vtx1.r, &vtx1.flat_r);
+			copyColors(&gDP.primColor.r, &vtx2.r, &vtx2.flat_r);
+		} else if ((gSP.geometryMode & G_SHADING_SMOOTH) == 0) {
 			// Flat shading
-			SPVertex & vtx0 = triangles.vertices[_v0 + ((RSP.w1 >> 24) & 3)];
-			SPVertex & vtx1 = triangles.vertices[_v0];
-			vtx1.r = vtx1.flat_r = vtx0.r;
-			vtx1.g = vtx1.flat_g = vtx0.g;
-			vtx1.b = vtx1.flat_b = vtx0.b;
-			vtx1.a = vtx1.flat_a = vtx0.a;
-			SPVertex & vtx2 = triangles.vertices[_v1];
-			vtx2.r = vtx2.flat_r = vtx0.r;
-			vtx2.g = vtx2.flat_g = vtx0.g;
-			vtx2.b = vtx2.flat_b = vtx0.b;
-			vtx2.a = vtx2.flat_a = vtx0.a;
+			copyColors(&_v0.r, &vtx1.r, &vtx1.flat_r);
+			copyColors(&_v0.r, &vtx2.r, &vtx2.flat_r);
 		}
 	}
+	else {
+		convertNormalsToColors(&vtx1.nx, &vtx1.r);
+		convertNormalsToColors(&vtx2.nx, &vtx2.r);
+	}
+}
+
+void GraphicsDrawer::_drawThickLine(u32 _v0, u32 _v1, float _width, u32 _flag)
+{
+	SPVertex vertexBuf[2] = { triangles.vertices[_v0], triangles.vertices[_v1] };
+	correctLineVerticesColor(vertexBuf, triangles.vertices[_flag]);
 
 	setDMAVerticesSize(4);
 	SPVertex * pVtx = getDMAVerticesData();
 	const f32 ySign = GBI.isNegativeY() ? -1.0f : 1.0f;
-	pVtx[0] = triangles.vertices[_v0];
+	pVtx[0] = vertexBuf[0];
 	pVtx[0].x = pVtx[0].x / pVtx[0].w * gSP.viewport.vscale[0] + gSP.viewport.vtrans[0];
 	pVtx[0].y = ySign * pVtx[0].y / pVtx[0].w * gSP.viewport.vscale[1] + gSP.viewport.vtrans[1];
 	pVtx[0].z = pVtx[0].z / pVtx[0].w;
 	pVtx[1] = pVtx[0];
 
-	pVtx[2] = triangles.vertices[_v1];
+	pVtx[2] = vertexBuf[1];
 	pVtx[2].x = pVtx[2].x / pVtx[2].w * gSP.viewport.vscale[0] + gSP.viewport.vtrans[0];
 	pVtx[2].y = ySign * pVtx[2].y / pVtx[2].w * gSP.viewport.vscale[1] + gSP.viewport.vtrans[1];
 	pVtx[2].z = pVtx[2].z / pVtx[2].w;
@@ -1060,7 +1072,7 @@ void GraphicsDrawer::_drawThickLine(u32 _v0, u32 _v1, float _width)
 	drawScreenSpaceTriangle(4);
 }
 
-void GraphicsDrawer::drawLine(u32 _v0, u32 _v1, float _width)
+void GraphicsDrawer::drawLine(u32 _v0, u32 _v1, float _width, u32 _flag)
 {
 	m_texrectDrawer.draw();
 	m_statistics.lines++;
@@ -1073,8 +1085,9 @@ void GraphicsDrawer::drawLine(u32 _v0, u32 _v1, float _width)
 		lineWidth *= dwnd().getScaleX();
 	else
 		lineWidth *= config.frameBufferEmulation.nativeResFactor;
+
 	if (lineWidth > m_maxLineWidth) {
-		_drawThickLine(_v0, _v1, _width * 0.5f);
+		_drawThickLine(_v0, _v1, _width * 0.5f, _flag);
 		return;
 	}
 
@@ -1089,6 +1102,8 @@ void GraphicsDrawer::drawLine(u32 _v0, u32 _v1, float _width)
 		_updateViewport();
 
 	SPVertex vertexBuf[2] = { triangles.vertices[_v0], triangles.vertices[_v1] };
+	correctLineVerticesColor(vertexBuf, triangles.vertices[_flag]);
+
 	gfxContext.drawLine(lineWidth, vertexBuf);
 	dropRenderState();
 }

src/GraphicsDrawer.h

@@ -53,7 +53,7 @@ class GraphicsDrawer
 
 	void drawDMATriangles(u32 _numVtx);
 
-	void drawLine(u32 _v0, u32 _v1, float _width);
+	void drawLine(u32 _v0, u32 _v1, float _width, u32 _flag);
 
 	void drawRect(int _ulx, int _uly, int _lrx, int _lry);
 
@@ -210,7 +210,7 @@ class GraphicsDrawer
 	void _updateStates(DrawingState _drawingState) const;
 	void _prepareDrawTriangle(DrawingState _drawingState);
 	bool _canDraw() const;
-	void _drawThickLine(u32 _v0, u32 _v1, float _width);
+	void _drawThickLine(u32 _v0, u32 _v1, float _width, u32 _flag);
 
 	void _drawOSD(const char *_pText, float _x, float & _y);
 

src/gSP.cpp

@@ -1974,7 +1974,7 @@ void gSPSetOtherMode_L(u32 _length, u32 _shift, u32 _data)
 
 void gSPLine3D(u32 v0, u32 v1, s32 wd, u32 flag )
 {
-	dwnd().getDrawer().drawLine(v0, v1, 1.5f + wd * 0.5f);
+	dwnd().getDrawer().drawLine(v0, v1, 1.5f + wd * 0.5f, flag);
 
 	DebugMsg(DEBUG_NORMAL, "gSPLine3D( %i, %i, %i, %i )\n", v0, v1, wd, flag);
 }