I turned on hardware acceleration for my graphics card, and

everything broke; apparently that driver didn't like me continually
destroying and recreating the HPGL context, and it also didn't like
me drawing zero-area polygons for my edges (which seemed like a
good idea, because it let me use glPolygonOffset instead of doing
that by hand). So it now all seems to work again, and faster.

[git-p4: depot-paths = "//depot/solvespace/": change = 1723]

entity.cpp

@@ -508,16 +508,13 @@ Quaternion Entity::PointGetQuaternion(void) {
 
 void Entity::LineDrawOrGetDistance(Vector a, Vector b) {
     if(dogd.drawing) {
-        glPolygonOffset(-5, -5);
-        glPolygonMode(GL_FRONT_AND_BACK, GL_LINE);
-        // Have to draw this as a polygon in order to make the offset work.
-        glBegin(GL_TRIANGLES);
-            glxVertex3v(a);
-            glxVertex3v(b);
-            glxVertex3v(b);
+        // glPolygonOffset works only on polys, not lines, so do it myself
+        Vector adj = SS.GW.projRight.Cross(SS.GW.projUp);
+        adj = adj.ScaledBy(5/SS.GW.scale);
+        glBegin(GL_LINES);
+            glxVertex3v(a.Plus(adj));
+            glxVertex3v(b.Plus(adj));
         glEnd();
-        glPolygonOffset(0, 0);
-        glPolygonMode(GL_FRONT_AND_BACK, GL_FILL);
     } else {
         Point2d ap = SS.GW.ProjectPoint(a);
         Point2d bp = SS.GW.ProjectPoint(b);

graphicswin.cpp

@@ -1065,7 +1065,7 @@ void GraphicsWindow::Paint(int w, int h) {
     glMatrixMode(GL_PROJECTION); 
     glLoadIdentity();
 
-    glScaled(scale*2.0/w, scale*2.0/h, scale*1.0/50000);
+    glScaled(scale*2.0/w, scale*2.0/h, scale*1.0/10000);
 
     double tx = projRight.Dot(offset);
     double ty = projUp.Dot(offset);

win32/w32main.cpp

@@ -24,6 +24,7 @@ int TextWndScrollPos; // The scrollbar position, in half-row units
 int TextWndHalfRows;  // The height of our window, in half-row units
 
 HWND GraphicsWnd;
+HGLRC GraphicsHpgl;
 HWND GraphicsEditControl;
 HMENU SubMenus[100];
 struct {
@@ -393,8 +394,10 @@ void ShowTextWindow(BOOL visible)
     ShowWindow(TextWnd, visible ? SW_SHOWNOACTIVATE : SW_HIDE);
 }
 
-static HGLRC CreateGlContext(HDC hdc)
-{
+static void CreateGlContext(void)
+{   
+    HDC hdc = GetDC(GraphicsWnd);
+
     PIXELFORMATDESCRIPTOR pfd;
     int pixelFormat; 
 
@@ -405,7 +408,7 @@ static HGLRC CreateGlContext(HDC hdc)
                         PFD_DOUBLEBUFFER; 
     pfd.dwLayerMask = PFD_MAIN_PLANE; 
     pfd.iPixelType = PFD_TYPE_RGBA; 
-    pfd.cColorBits = 8; 
+    pfd.cColorBits = 16; 
     pfd.cDepthBits = 16; 
     pfd.cAccumBits = 0; 
     pfd.cStencilBits = 0; 
@@ -415,37 +418,25 @@ static HGLRC CreateGlContext(HDC hdc)
  
     if(!SetPixelFormat(hdc, pixelFormat, &pfd)) oops();
 
-    HGLRC hgrc = wglCreateContext(hdc); 
-    wglMakeCurrent(hdc, hgrc); 
-
-    return hgrc;
+    GraphicsHpgl = wglCreateContext(hdc); 
+    wglMakeCurrent(hdc, GraphicsHpgl); 
 }
 
 void InvalidateGraphics(void)
 {
     InvalidateRect(GraphicsWnd, NULL, FALSE);
 }
-static void PaintGraphicsWithHdc(HDC hdc)
+void PaintGraphics(void)
 {
-    HGLRC hgrc = CreateGlContext(hdc);
-
     RECT r;
     GetClientRect(GraphicsWnd, &r);
     int w = r.right - r.left;
     int h = r.bottom - r.top;
 
     SS.GW.Paint(w, h);
-
-    SwapBuffers(hdc);
-
-    wglMakeCurrent(NULL, NULL);
-    wglDeleteContext(hgrc);
-}
-void PaintGraphics(void)
-{
-    HDC hdc = GetDC(GraphicsWnd);
-    PaintGraphicsWithHdc(hdc);
+    SwapBuffers(GetDC(GraphicsWnd));
 }
+
 SDWORD GetMilliseconds(void)
 {
     return (SDWORD)GetTickCount();
@@ -494,12 +485,9 @@ LRESULT CALLBACK GraphicsWndProc(HWND hwnd, UINT msg, WPARAM wParam,
             break;
 
         case WM_PAINT: {
-            InvalidateRect(GraphicsWnd, NULL, FALSE);
+            PaintGraphics();
             PAINTSTRUCT ps;
             HDC hdc = BeginPaint(hwnd, &ps);
-
-            PaintGraphicsWithHdc(hdc);
-
             EndPaint(hwnd, &ps);
             break;
         }
@@ -711,6 +699,8 @@ static void CreateMainWindows(void)
         600, 300, 200, 200, NULL, top, Instance, NULL);
     if(!GraphicsWnd) oops();
 
+    CreateGlContext();
+
     GraphicsEditControl = CreateWindowEx(WS_EX_CLIENTEDGE, WC_EDIT, "",
         WS_CHILD | ES_AUTOHSCROLL | WS_TABSTOP | WS_CLIPSIBLINGS,
         50, 50, 100, 21, GraphicsWnd, NULL, Instance, NULL);