polymost.cpp: Fix polymost_domost() issue with COMBINE_STRIPS where in certain cases, merging with the viewport nodes caused accidental reading of sentinel node values.

Additional debug code is included for visualizing the state of the vsp data structure.
Further, fix issue in drawpoly where it would access out of bounds of dpxy if fewer than 3 vertices were passed in and fix issue where multiple calls to polymost_setVisibility() were repeatedly setting the visibility factor to the same value.

git-svn-id: https://svn.eduke32.com/eduke32@7737 1a8010ca-5511-0410-912e-c29ae57300e0

source/build/src/polymost.cpp

@@ -28,7 +28,7 @@ int32_t usehightile=1;
 typedef struct { float x, cy[2], fy[2]; int32_t tag; int16_t n, p, ctag, ftag; } vsptyp;
 #define VSPMAX 2048 //<- careful!
 static vsptyp vsp[VSPMAX];
-static int32_t gtag;
+static int32_t gtag, viewportNodeCount;
 static float xbl, xbr, xbt, xbb;
 int32_t domost_rejectcount;
 #ifdef YAX_ENABLE
@@ -639,7 +639,11 @@ static void polymost_setVisibility(float visibility)
     if (currentShaderProgramID != polymost1CurrentShaderProgramID)
         return;
 
-    polymost1VisFactor = visibility * fviewingrange * (1.f / (64.f * 65536.f));
+    float visFactor = visibility * fviewingrange * (1.f / (64.f * 65536.f));
+    if (visFactor == polymost1VisFactor)
+        return;
+
+    polymost1VisFactor = visFactor;
     glUniform1f(polymost1VisFactorLoc, polymost1VisFactor);
 }
 
@@ -2244,7 +2248,7 @@ static void polymost_drawpoly(vec2f_t const * const dpxy, int32_t const n, int32
         if ((dpxy[0].x-dpxy[1].x) * (dpxy[2].y-dpxy[1].y) >=
             (dpxy[2].x-dpxy[1].x) * (dpxy[0].y-dpxy[1].y)) return; //for triangle
     }
-    else
+    else if (n > 3)
     {
         float f = 0; //f is area of polygon / 2
 
@@ -3087,6 +3091,38 @@ skip: ;
             if ((vsp[ni].tag == 0) || (n1.y <= vsp[i].cy[1]+DOMOST_OFFSET)) k -= 3;
             if ((vsp[ni].tag == 1) || (n1.y >= vsp[i].fy[1]-DOMOST_OFFSET)) k += 3;
 
+#if 0
+            //POGO: This GL1 debug code draws a green line that represents the new line, and the current VSP floor & ceil as red and blue respectively.
+            //      To enable this, ensure that in polymost_drawrooms() that you are clearing the stencil buffer and color buffer.
+            //      Additionally, disable any calls to glColor4f in polymost_drawpoly and disable culling triangles with area==0/removing duplicate points
+            //      If you don't want any lines showing up from mirrors/skyboxes, be sure to disable them as well.
+            glEnable(GL_STENCIL_TEST);
+            glStencilOp(GL_REPLACE, GL_REPLACE, GL_REPLACE);
+            glStencilFunc(GL_ALWAYS, 1, 0xFF);
+            glDisable(GL_DEPTH_TEST);
+            polymost_useColorOnly(true);
+            glPolygonMode(GL_FRONT_AND_BACK,GL_LINE);
+
+            glColor4f(0.f, 1.f, 0.f, 1.f);
+            vec2f_t nline[3] = {{dx0, n0.y}, {dx1, n1.y}, {dx0, n0.y}};
+            polymost_drawpoly(nline, 3, domostpolymethod);
+
+            glColor4f(1.f, 0.f, 0.f, 1.f);
+            vec2f_t floor[3] = {{vsp[i].x, vsp[i].fy[0]}, {vsp[ni].x, vsp[i].fy[1]}, {vsp[i].x, vsp[i].fy[0]}};
+            polymost_drawpoly(floor, 3, domostpolymethod);
+
+            glColor4f(0.f, 0.f, 1.f, 1.f);
+            vec2f_t ceil[3] = {{vsp[i].x, vsp[i].cy[0]}, {vsp[ni].x, vsp[i].cy[1]}, {vsp[i].x, vsp[i].cy[0]}};
+            polymost_drawpoly(ceil, 3, domostpolymethod);
+
+            glPolygonMode(GL_FRONT_AND_BACK,GL_FILL);
+            polymost_useColorOnly(false);
+            glEnable(GL_DEPTH_TEST);
+            glStencilOp(GL_KEEP, GL_KEEP, GL_KEEP);
+            glStencilFunc(GL_EQUAL, 0, 0xFF);
+            glColor4f(1.f, 1.f, 1.f, 1.f);
+#endif
+
             if (!dir)
             {
                 switch (k)
@@ -3307,11 +3343,41 @@ skip: ;
 
         int const ni = vsp[i].n;
 
-        if ((vsp[i].ctag == vsp[ni].ctag) && (vsp[i].ftag == vsp[ni].ftag))
+        //POGO: specially treat the viewport nodes so that we will never end up in a situation where we accidentally access the sentinel node
+        if (ni >= viewportNodeCount &&
+            (vsp[i].ctag == vsp[ni].ctag) && (vsp[i].ftag == vsp[ni].ftag))
         {
             vsp[i].cy[1] = vsp[ni].cy[1];
             vsp[i].fy[1] = vsp[ni].fy[1];
             vsdel(ni);
+
+#if 0
+            //POGO: This GL1 debug code draws the resulting merged VSP segment with floor and ceiling bounds lines as yellow and cyan respectively
+            //      To enable this, ensure that in polymost_drawrooms() that you are clearing the stencil buffer and color buffer.
+            //      Additionally, disable any calls to glColor4f in polymost_drawpoly and disable culling triangles with area==0
+            //      If you don't want any lines showing up from mirrors/skyboxes, be sure to disable them as well.
+            glEnable(GL_STENCIL_TEST);
+            glStencilOp(GL_REPLACE, GL_REPLACE, GL_REPLACE);
+            glStencilFunc(GL_ALWAYS, 1, 0xFF);
+            glDisable(GL_DEPTH_TEST);
+            polymost_useColorOnly(true);
+            glPolygonMode(GL_FRONT_AND_BACK,GL_LINE);
+
+            glColor4f(1.f, 1.f, 0.f, 1.f);
+            vec2f_t dfloor[3] = {{vsp[i].x, vsp[i].fy[0]}, {vsp[vsp[i].n].x, vsp[i].fy[1]}, {vsp[i].x, vsp[i].fy[0]}};
+            polymost_drawpoly(dfloor, 3, domostpolymethod);
+
+            glColor4f(0.f, 1.f, 1.f, 1.f);
+            vec2f_t dceil[3] = {{vsp[i].x, vsp[i].cy[0]}, {vsp[vsp[i].n].x, vsp[i].cy[1]}, {vsp[i].x, vsp[i].cy[0]}};
+            polymost_drawpoly(dceil, 3, domostpolymethod);
+
+            glPolygonMode(GL_FRONT_AND_BACK,GL_FILL);
+            polymost_useColorOnly(false);
+            glEnable(GL_DEPTH_TEST);
+            glStencilOp(GL_KEEP, GL_KEEP, GL_KEEP);
+            glStencilFunc(GL_EQUAL, 0, 0xFF);
+            glColor4f(1.f, 1.f, 1.f, 1.f);
+#endif
         }
         else i = ni;
     }
@@ -3903,6 +3969,9 @@ static void polymost_internal_nonparallaxed(vec2f_t n0, vec2f_t n1, float ryp0,
 
     float ft[4] = { fglobalposx, fglobalposy, fcosglobalang, fsinglobalang };
 
+    polymost_outputGLDebugMessage(3, "polymost_internal_nonparallaxed(n0:{x:%f, y:%f}, n1:{x:%f, y:%f}, ryp0:%f, ryp1:%f, x0:%f, x1:%f, y0:%f, y1:%f, sectnum:%d)",
+                                  n0.x, n0.y, n1.x, n1.y, ryp0, ryp1, x0, x1, y0, y1, sectnum);
+
     if (globalorientation & 64)
     {
         //relative alignment
@@ -5428,6 +5497,7 @@ static void polymost_initmosts(const float * px, const float * py, int const n)
     }
 
     gtag = vcnt;
+    viewportNodeCount = vcnt;
 }
 
 void polymost_drawrooms()