Refactor|Renderer: Renamed obscure 'gzt' parameter

VisEntityPose now has methods for calculating the middle point or
middle Z of the entity. The 'gzt' member (global z top) was renamed
to be more understandable 'topZ'.

doomsday/client/include/render/rend_main.h

@@ -54,7 +54,7 @@ class LightGrid;
 
 #define SHADOW_SURFACE_LUMINOSITY_ATTRIBUTION_MIN (.05f)
 
-DENG_EXTERN_C de::Vector3d vOrigin;
+DENG_EXTERN_C de::Vector3d vOrigin; // Y/Z swizzled for drawing
 DENG_EXTERN_C float vang, vpitch, yfov;
 DENG_EXTERN_C float viewsidex, viewsidey;
 DENG_EXTERN_C float fogColor[4];

doomsday/client/include/render/vissprite.h

@@ -43,9 +43,9 @@ typedef enum {
 struct VisEntityPose
 {
     de::Vector3d    origin;
-    float           gzt; // The real center point and global top z for silhouette clipping.
-    de::Vector3d    srvo; // Short-range visual offset.
-    coord_t         distance; // Distance from viewer.
+    float           topZ; ///< Global top Z coordinate (origin Z is the bottom).
+    de::Vector3d    srvo; ///< Short-range visual offset.
+    coord_t         distance; ///< Distance from viewer.
     float           yaw;
     float           extraYawAngle;
     float           yawAngleOffset; ///< @todo We do not need three sets of angles...
@@ -54,20 +54,20 @@ struct VisEntityPose
     float           pitchAngleOffset;
     float           extraScale;
     bool            viewAligned;
-    bool            mirrored; // If true the model will be mirrored about its Z axis (in model space).
+    bool            mirrored; ///< If true the model will be mirrored about its Z axis (in model space).
 
     VisEntityPose() { de::zap(*this); }
 
     VisEntityPose(de::Vector3d const &origin_,
                   de::Vector3d const &visOffset,
                   bool viewAlign_ = false,
-                  float gzt_ = 0,
+                  float topZ_ = 0,
                   float yaw_ = 0,
                   float yawAngleOffset_ = 0,
                   float pitch_ = 0,
                   float pitchAngleOffset_= 0)
         : origin(origin_)
-        , gzt(gzt_)
+        , topZ(topZ_)
         , srvo(visOffset)
         , distance(Rend_PointDist2D(origin_))
         , yaw(yaw_)
@@ -80,6 +80,10 @@ struct VisEntityPose
         , viewAligned(viewAlign_)
         , mirrored(false)
     {}
+
+    inline coord_t midZ() const { return (origin.z + topZ) / 2; }
+
+    de::Vector3d mid() const { return de::Vector3d(origin.x, origin.y, midZ()); }
 };
 
 struct VisEntityLighting
@@ -158,7 +162,7 @@ typedef struct vispsprite_s {
         } sprite;
         struct vispsprite_model_s {
             BspLeaf *bspLeaf;
-            coord_t gzt; // global top for silhouette clipping
+            coord_t topZ; // global top for silhouette clipping
             int flags; // for color translation and shadow draw
             uint id;
             int selector;

doomsday/client/src/render/r_main.cpp

@@ -208,7 +208,7 @@ static void setupModelParamsForVisPSprite(vissprite_t &vis, vispsprite_t const *
     vis.pose.srvo[VX] = spr->data.model.visOff[VX];
     vis.pose.srvo[VY] = spr->data.model.visOff[VY];
     vis.pose.srvo[VZ] = spr->data.model.visOff[VZ] - spr->data.model.floorClip;
-    vis.pose.gzt = spr->data.model.gzt;
+    vis.pose.topZ = spr->data.model.topZ;
     vis.pose.distance = -10;
     vis.pose.yaw = spr->data.model.yaw;
     vis.pose.extraYawAngle = 0;

doomsday/client/src/render/r_things.cpp

@@ -323,7 +323,7 @@ void R_ProjectSprite(mobj_t *mo)
         findMobjZOrigin(mo, floorAdjust, vis);
     }
 
-    coord_t gzt = vis->pose.origin.z + -tex.origin().y;
+    coord_t topZ = vis->pose.origin.z + -tex.origin().y; // global z top
 
     // Determine floor clipping.
     coord_t floorClip = mo->floorClip;
@@ -378,7 +378,7 @@ void R_ProjectSprite(mobj_t *mo)
         if(mf->testSubFlag(0, MFF_ALIGN_PITCH))
         {
             viewdata_t const *viewData = R_ViewData(viewPlayer - ddPlayers);
-            Vector2d delta((vis->pose.origin.z + gzt) / 2 - viewData->current.origin.z, distFromEye);
+            Vector2d delta(vis->pose.midZ() - viewData->current.origin.z, distFromEye);
 
             pitch = -BANG2DEG(bamsAtan2(delta.x * 10, delta.y * 10));
         }
@@ -438,16 +438,16 @@ void R_ProjectSprite(mobj_t *mo)
         if(ms.height() < ceiling.heightSmoothed() - floor.heightSmoothed())
         {
             // Sprite fits in, adjustment possible?
-            if(fitTop && gzt > ceiling.heightSmoothed())
-                gzt = ceiling.heightSmoothed();
+            if(fitTop && topZ > ceiling.heightSmoothed())
+                topZ = ceiling.heightSmoothed();
 
-            if(floorAdjust && fitBottom && gzt - ms.height() < floor.heightSmoothed())
-                gzt = floor.heightSmoothed() + ms.height();
+            if(floorAdjust && fitBottom && topZ - ms.height() < floor.heightSmoothed())
+                topZ = floor.heightSmoothed() + ms.height();
         }
         // Adjust by the floor clip.
-        gzt -= floorClip;
+        topZ -= floorClip;
 
-        Vector3d const origin(vis->pose.origin.x, vis->pose.origin.y, gzt - ms.height() / 2.0f);
+        Vector3d const origin(vis->pose.origin.x, vis->pose.origin.y, topZ - ms.height() / 2.0f);
         Vector4f ambientColor;
         uint vLightListIdx = 0;
         evaluateLighting(origin, &Mobj_BspLeafAtOrigin(*mo), vis->pose.distance, fullbright,
@@ -460,7 +460,7 @@ void R_ProjectSprite(mobj_t *mo)
                               VisEntityPose(origin, visOff, viewAlign),
                               VisEntityLighting(ambientColor, vLightListIdx),
                               floor.heightSmoothed(), ceiling.heightSmoothed(),
-                              floorClip, gzt, *mat, matFlipS, matFlipT, blendMode,                              
+                              floorClip, topZ, *mat, matFlipS, matFlipT, blendMode,
                               mo->tclass, mo->tmap,
                               &Mobj_BspLeafAtOrigin(*mo),
                               floorAdjust, fitTop, fitBottom);
@@ -480,7 +480,7 @@ void R_ProjectSprite(mobj_t *mo)
             // Set up a GL2 model for drawing.
             vis->pose = VisEntityPose(vis->pose.origin,
                                       Vector3d(visOff.x, visOff.y, visOff.z - floorClip),
-                                      viewAlign, gzt, yaw, 0, pitch, 0);
+                                      viewAlign, topZ, yaw, 0, pitch, 0);
             vis->light = VisEntityLighting(ambientColor, vLightListIdx);
 
             vis->data.model2.object   = mo;
@@ -493,7 +493,7 @@ void R_ProjectSprite(mobj_t *mo)
             VisSprite_SetupModel(vis,
                                  VisEntityPose(vis->pose.origin,
                                                Vector3d(visOff.x, visOff.y, visOff.z - floorClip),
-                                               viewAlign, gzt, yaw, 0, pitch, 0),
+                                               viewAlign, topZ, yaw, 0, pitch, 0),
                                  VisEntityLighting(ambientColor, vLightListIdx),
                                  mf, nextmf, interp,
                                  mo->thinker.id, mo->selector,

doomsday/client/src/render/rend_model.cpp

@@ -811,7 +811,7 @@ static void drawSubmodel(uint number, vissprite_t const &spr)
     }
 
     // Coordinates to the center of the model (game coords).
-    modelCenter = Vector3f(spr.pose.origin[VX], spr.pose.origin[VY], (spr.pose.origin[VZ] + spr.pose.gzt) * 2)
+    modelCenter = Vector3f(spr.pose.origin[VX], spr.pose.origin[VY], spr.pose.midZ())
             + Vector3d(spr.pose.srvo) + Vector3f(mf->offset.x, mf->offset.z, mf->offset.y);
 
     // Calculate lighting.

doomsday/client/src/render/rend_particle.cpp

@@ -385,7 +385,7 @@ static void setupModelParamsForParticle(vissprite_t &spr,
     // Render the particle as a model.
     spr.pose.origin[VX] = origin.x;
     spr.pose.origin[VY] = origin.z;
-    spr.pose.origin[VZ] = spr.pose.gzt = origin.y;
+    spr.pose.origin[VZ] = spr.pose.topZ = origin.y;
     spr.pose.distance = dist;
 
     spr.pose.extraScale = size; // Extra scaling factor.

doomsday/client/src/render/sky.cpp

@@ -384,7 +384,7 @@ DENG2_PIMPL(Sky)
             temp.pose.origin[VX]   = vOrigin.x * -minfo.def->coordFactor[VX];
             temp.pose.origin[VY]   = vOrigin.z * -minfo.def->coordFactor[VZ];
             temp.pose.origin[VZ]   = vOrigin.y * -minfo.def->coordFactor[VY];
-            temp.pose.gzt          = temp.pose.origin[VZ];
+            temp.pose.topZ         = temp.pose.origin[VZ];
             temp.pose.distance     = 1;
 
             temp.pose.extraYawAngle   = temp.pose.yawAngleOffset   = minfo.def->rotate[0];

doomsday/client/src/render/viewports.cpp

@@ -801,7 +801,7 @@ static void setupPlayerSprites()
             spr->data.model.bspLeaf = &Mobj_BspLeafAtOrigin(*mo);
             spr->data.model.flags = 0;
             // 32 is the raised weapon height.
-            spr->data.model.gzt = viewData->current.origin.z;
+            spr->data.model.topZ = viewData->current.origin.z;
             spr->data.model.secFloor = cluster.visFloor().heightSmoothed();
             spr->data.model.secCeil  = cluster.visCeiling().heightSmoothed();
             spr->data.model.pClass = 0;