From 39300b18a854786f3688f0370d234172bf8dce72 Mon Sep 17 00:00:00 2001
From: AzaezelX <quillus@hotmail.com>
Date: Wed, 28 Aug 2024 10:33:12 -0500
Subject: [PATCH] fix misbehaving imposter display corrects display of
 imposters when pole capture is on

---
 .../core/rendering/shaders/gl/imposter.glsl   | 27 ++++++++++---------
 .../game/core/rendering/shaders/imposter.hlsl | 21 ++++++++-------
 2 files changed, 25 insertions(+), 23 deletions(-)

diff --git a/Templates/BaseGame/game/core/rendering/shaders/gl/imposter.glsl b/Templates/BaseGame/game/core/rendering/shaders/gl/imposter.glsl
index 20bc62688a..8bd32e8ab1 100644
--- a/Templates/BaseGame/game/core/rendering/shaders/gl/imposter.glsl
+++ b/Templates/BaseGame/game/core/rendering/shaders/gl/imposter.glsl
@@ -22,7 +22,7 @@
 
 #include "torque.glsl"
 
-
+#line 25
 #define IMPOSTER_MAX_UVS 64
 
 
@@ -94,24 +94,22 @@ void imposter_v(
 
     // First check to see if we need to render the top billboard.   
     int index;
-    /*
-    if ( includePoles && ( lookPitch < polarAngle || lookPitch > sPi - polarAngle ) )
+    if ( includePoles && ( lookPitch < polarHalfStep || lookPitch > M_PI_F - polarHalfStep ) )
     {
-      index = numEquatorSteps * 3; 
+      index = numEquatorSteps * numPolarSteps; 
 
       // When we render the top/bottom billboard we always use
       // a fixed vector that matches the rotation of the object.
       rightVec = vec3( 1, 0, 0 ) * sCornerRight[corner];
-      upVec = vec3( 0, 1, 0 ) * sCornerUp[corner];
+      upVec = vec3( 0, -1, 0 ) * sCornerUp[corner];
 
-      if ( lookPitch > sPi - polarAngle )
+      if ( lookPitch < polarHalfStep )
       {
          upVec = -upVec;
          index++;
       }
     }
     else
-    */
     {
         // Calculate the rotation around the z axis then add the
         // equator half step.  This gets the images to switch a
@@ -126,20 +124,23 @@ void imposter_v(
 
         // TODO: How can we do this without conditionals?
         // Normalize the result to 0 to 2PI.
-        if ( rotZ < 0.0 )
+        if ( rotZ < 0 )
             rotZ += M_2PI_F;
-        if ( rotZ > M_2PI_F )
+        else if ( rotZ > M_2PI_F )
             rotZ -= M_2PI_F;
-        if ( rotY < 0.0 )
+            
+        if ( rotY < 0 )
             rotY += M_2PI_F;
-        if ( rotY > M_PI_F ) // Not M_2PI_F?
+        else if ( rotY > M_2PI_F )
             rotY -= M_2PI_F;
 
-        float polarIdx = round( abs( rotY ) / polarStepSize );
+        int polarIdx = int(max(min(round( rotY / polarStepSize ), numPolarSteps-2),0));
 
         // Get the index to the start of the right polar
         // images for this viewing angle.
-        int numPolarOffset = int( float( numEquatorSteps ) * polarIdx );
+        int numPolarOffset = numEquatorSteps * polarIdx;
+        if (includePoles)
+            numPolarOffset = (numEquatorSteps+2) * polarIdx;
 
         // Calculate the final image index for lookup 
         // of the texture coords.
diff --git a/Templates/BaseGame/game/core/rendering/shaders/imposter.hlsl b/Templates/BaseGame/game/core/rendering/shaders/imposter.hlsl
index bc700ba030..2373271aa6 100644
--- a/Templates/BaseGame/game/core/rendering/shaders/imposter.hlsl
+++ b/Templates/BaseGame/game/core/rendering/shaders/imposter.hlsl
@@ -82,24 +82,22 @@ void imposter_v(
 
     // First check to see if we need to render the top billboard.   
     int index;
-    /*
-    if ( includePoles && ( lookPitch < polarAngle || lookPitch > sPi - polarAngle ) )
+    if ( includePoles && ( lookPitch < polarHalfStep || lookPitch > (M_PI_F - polarHalfStep) ) )
     {
-      index = numEquatorSteps * 3; 
+      index = numEquatorSteps * numPolarSteps; 
 
       // When we render the top/bottom billboard we always use
       // a fixed vector that matches the rotation of the object.
       rightVec = float3( 1, 0, 0 ) * sCornerRight[corner];
-      upVec = float3( 0, 1, 0 ) * sCornerUp[corner];
+      upVec = float3( 0, -1, 0 ) * sCornerUp[corner];
 
-      if ( lookPitch > sPi - polarAngle )
+      if ( lookPitch < polarHalfStep )
       {
          upVec = -upVec;
          index++;
       }
     }
     else
-    */
     {
         // Calculate the rotation around the z axis then add the
         // equator half step.  This gets the images to switch a
@@ -116,19 +114,22 @@ void imposter_v(
         // Normalize the result to 0 to 2PI.
         if ( rotZ < 0 )
             rotZ += M_2PI_F;
-        if ( rotZ > M_2PI_F )
+        else if ( rotZ > M_2PI_F )
             rotZ -= M_2PI_F;
+            
         if ( rotY < 0 )
             rotY += M_2PI_F;
-        if ( rotY > M_PI_F ) // Not M_2PI_F?
+        else if ( rotY > M_2PI_F )
             rotY -= M_2PI_F;
 
-        float polarIdx = round( abs( rotY ) / polarStepSize );
+        int polarIdx = max(min(round( rotY / polarStepSize ), numPolarSteps-2),0);
 
         // Get the index to the start of the right polar
         // images for this viewing angle.
         int numPolarOffset = numEquatorSteps * polarIdx;
-
+        if (includePoles)
+            numPolarOffset = (numEquatorSteps+2) * polarIdx;
+            
         // Calculate the final image index for lookup 
         // of the texture coords.
         index = ( rotZ / equatorStepSize ) + numPolarOffset;