Water Exclusion Surfaces (#3517)

* #3455 Add support for water exclusion surfaces

18 files changed, 396 insertions, 31 deletions

diff --git a/indra/newview/CMakeLists.txt b/indra/newview/CMakeLists.txt
index 5bcfddfe25..d2736c7c12 100644
--- a/indra/newview/CMakeLists.txt
+++ b/indra/newview/CMakeLists.txt
@@ -156,6 +156,7 @@ set(viewer_SOURCE_FILES
     lldrawpooltree.cpp
     lldrawpoolwater.cpp
     lldrawpoolwlsky.cpp
+    lldrawpoolwaterexclusion.cpp
     lldynamictexture.cpp
     llemote.cpp
     llenvironment.cpp
@@ -823,6 +824,7 @@ set(viewer_HEADER_FILES
     lldrawpooltree.h
     lldrawpoolwater.h
     lldrawpoolwlsky.h
+    lldrawpoolwaterexclusion.h
     lldynamictexture.h
     llemote.h
     llenvironment.h
diff --git a/indra/newview/app_settings/shaders/class1/objects/simpleColorF.glsl b/indra/newview/app_settings/shaders/class1/objects/simpleColorF.glsl
new file mode 100644
index 0000000000..dea76da5a5
--- /dev/null
+++ b/indra/newview/app_settings/shaders/class1/objects/simpleColorF.glsl
@@ -0,0 +1,57 @@
+/**
+ * @file simpleColorF.glsl
+ *
+ * $LicenseInfo:firstyear=2025&license=viewerlgpl$
+ * Second Life Viewer Source Code
+ * Copyright (C) 2007, Linden Research, Inc.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation;
+ * version 2.1 of the License only.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ *
+ * Linden Research, Inc., 945 Battery Street, San Francisco, CA  94111  USA
+ * $/LicenseInfo$
+ */
+
+out vec4 frag_color;
+
+in vec4 vertex_color;
+in vec4 vertex_position;
+
+uniform vec4 waterPlane;
+uniform float waterSign;
+
+void waterClip(vec3 pos)
+{
+    // TODO: make this less branchy
+    if (waterSign > 0)
+    {
+        if ((dot(pos.xyz, waterPlane.xyz) + waterPlane.w) < 0.0)
+        {
+            discard;
+        }
+    }
+    else
+    {
+        if ((dot(pos.xyz, waterPlane.xyz) + waterPlane.w) > 0.0)
+        {
+            discard;
+        }
+    }
+}
+
+void main()
+{
+
+    frag_color = vertex_color;
+}
diff --git a/indra/newview/app_settings/shaders/class1/objects/simpleNoAtmosV.glsl b/indra/newview/app_settings/shaders/class1/objects/simpleNoAtmosV.glsl
new file mode 100644
index 0000000000..4564e56313
--- /dev/null
+++ b/indra/newview/app_settings/shaders/class1/objects/simpleNoAtmosV.glsl
@@ -0,0 +1,43 @@
+/**
+ * @file simpleNoAtmosV.glsl
+ *
+ * $LicenseInfo:firstyear=2007&license=viewerlgpl$
+ * Second Life Viewer Source Code
+ * Copyright (C) 2007, Linden Research, Inc.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation;
+ * version 2.1 of the License only.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ *
+ * Linden Research, Inc., 945 Battery Street, San Francisco, CA  94111  USA
+ * $/LicenseInfo$
+ */
+
+uniform mat4 modelview_matrix;
+uniform mat4 modelview_projection_matrix;
+
+uniform vec4 color;
+
+in vec3 position;
+
+out vec4 vertex_color;
+out vec4 vertex_position;
+
+void main()
+{
+    //transform vertex
+    vec4 pos = (modelview_matrix * vec4(position.xyz, 1.0));
+    vertex_position = modelview_projection_matrix * vec4(position.xyz, 1.0);
+    gl_Position = vertex_position;
+    vertex_color = color;
+}
diff --git a/indra/newview/app_settings/shaders/class3/deferred/waterHazeF.glsl b/indra/newview/app_settings/shaders/class3/deferred/waterHazeF.glsl
index ee49b4baae..091c25d15e 100644
--- a/indra/newview/app_settings/shaders/class3/deferred/waterHazeF.glsl
+++ b/indra/newview/app_settings/shaders/class3/deferred/waterHazeF.glsl
@@ -35,13 +35,25 @@ vec4 getWaterFogView(vec3 pos);
 
 uniform int above_water;
 
+uniform sampler2D exclusionTex;
+
 void main()
 {
     vec2  tc           = vary_fragcoord.xy/vary_fragcoord.w*0.5+0.5;
     float depth        = getDepth(tc.xy);
+    float mask = texture(exclusionTex, tc.xy).r;
 
     if (above_water > 0)
     {
+        // Just discard if we're in the exclusion mask.
+        // The previous invisiprim hack we're replacing would also crank up water fog desntiy.
+        // But doing that makes exclusion surfaces very slow as we'd need to render even more into the mask.
+        // - Geenz 2025-02-06
+        if (mask < 1)
+        {
+            discard;
+        }
+
         // we want to depth test when the camera is above water, but some GPUs have a hard time
         // with depth testing against render targets that are bound for sampling in the same shader
         // so we do it manually here
@@ -51,12 +63,14 @@ void main()
         {
             discard;
         }
+
     }
 
     vec4  pos          = getPositionWithDepth(tc, depth);
 
     vec4 fogged = getWaterFogView(pos.xyz);
     fogged.a = max(pow(fogged.a, 1.7), 0);
+
     frag_color = max(fogged, vec4(0)); //output linear since local lights will be added to this shader's results
 
 }
diff --git a/indra/newview/app_settings/shaders/class3/environment/underWaterF.glsl b/indra/newview/app_settings/shaders/class3/environment/underWaterF.glsl
index 1c02dc764d..fa410e9f11 100644
--- a/indra/newview/app_settings/shaders/class3/environment/underWaterF.glsl
+++ b/indra/newview/app_settings/shaders/class3/environment/underWaterF.glsl
@@ -26,6 +26,7 @@
 out vec4 frag_color;
 
 uniform sampler2D bumpMap;
+uniform sampler2D exclusionTex;
 
 #ifdef TRANSPARENT_WATER
 uniform sampler2D screenTex;
@@ -59,6 +60,9 @@ void mirrorClip(vec3 position);
 void main()
 {
     mirrorClip(vary_position);
+    vec2 screen_tc = (refCoord.xy/refCoord.z) * 0.5 + 0.5;
+    float water_mask = texture(exclusionTex, screen_tc).r;
+
     vec4 color;
 
     //get detail normals
@@ -68,8 +72,8 @@ void main()
     vec3 wavef = normalize(wave1+wave2+wave3);
 
     //figure out distortion vector (ripply)
-    vec2 distort = (refCoord.xy/refCoord.z) * 0.5 + 0.5;
-    distort = distort+wavef.xy*refScale;
+    vec2 distort = screen_tc;
+    distort = mix(distort, distort+wavef.xy*refScale, water_mask);
 
 #ifdef TRANSPARENT_WATER
     vec4 fb = texture(screenTex, distort);
diff --git a/indra/newview/app_settings/shaders/class3/environment/waterF.glsl b/indra/newview/app_settings/shaders/class3/environment/waterF.glsl
index f8aa684433..7027e3796e 100644
--- a/indra/newview/app_settings/shaders/class3/environment/waterF.glsl
+++ b/indra/newview/app_settings/shaders/class3/environment/waterF.glsl
@@ -88,7 +88,7 @@ uniform sampler2D screenTex;
 uniform sampler2D depthMap;
 #endif
 
-uniform sampler2D refTex;
+uniform sampler2D exclusionTex;
 
 uniform float sunAngle;
 uniform float sunAngle2;
@@ -252,6 +252,8 @@ void main()
 
     float shadow = 1.0f;
 
+    float water_mask = texture(exclusionTex, distort).r;
+
 #ifdef HAS_SUN_SHADOW
     shadow = sampleDirectionalShadow(pos.xyz, norm.xyz, distort);
 #endif
@@ -266,9 +268,8 @@ void main()
     vec3 refPos = getPositionWithNDC(vec3(distort*2.0-vec2(1.0), depth*2.0-1.0));
 
     // Calculate some distance fade in the water to better assist with refraction blending and reducing the refraction texture's "disconnect".
-    fade = max(0,min(1, (pos.z - refPos.z) / 10));
+    fade = max(0,min(1, (pos.z - refPos.z) / 10)) * water_mask;
     distort2 = mix(distort, distort2, min(1, fade * 10));
-
     depth = texture(depthMap, distort2).r;
 
     refPos = getPositionWithNDC(vec3(distort2 * 2.0 - vec2(1.0), depth * 2.0 - 1.0));
@@ -282,6 +283,9 @@ void main()
 
 #else
     vec4 fb = applyWaterFogViewLinear(viewVec*2048.0, vec4(1.0));
+
+    if (water_mask < 1)
+        discard;
 #endif
 
     float metallic = 1.0;
@@ -333,6 +337,7 @@ void main()
     color = mix(fb.rgb, color, fade);
 
     float spec = min(max(max(punctual.r, punctual.g), punctual.b), 0.05);
-    frag_color = min(vec4(1),max(vec4(color.rgb, spec), vec4(0)));
+
+    frag_color = min(vec4(1),max(vec4(color.rgb, spec * water_mask), vec4(0)));
 }
 
diff --git a/indra/newview/lldrawpool.cpp b/indra/newview/lldrawpool.cpp
index 7bd5206453..e60b3eb5dc 100644
--- a/indra/newview/lldrawpool.cpp
+++ b/indra/newview/lldrawpool.cpp
@@ -42,6 +42,7 @@
 #include "lldrawpooltree.h"
 #include "lldrawpoolterrain.h"
 #include "lldrawpoolwater.h"
+#include "lldrawpoolwaterexclusion.h"
 #include "llface.h"
 #include "llviewerobjectlist.h" // For debug listing.
 #include "pipeline.h"
@@ -119,6 +120,9 @@ LLDrawPool *LLDrawPool::createPool(const U32 type, LLViewerTexture *tex0)
     case POOL_GLTF_PBR_ALPHA_MASK:
         poolp = new LLDrawPoolGLTFPBR(LLDrawPool::POOL_GLTF_PBR_ALPHA_MASK);
         break;
+    case POOL_WATEREXCLUSION:
+        poolp = new LLDrawPoolWaterExclusion();
+        break;
     default:
         LL_ERRS() << "Unknown draw pool type!" << LL_ENDL;
         return NULL;
diff --git a/indra/newview/lldrawpool.h b/indra/newview/lldrawpool.h
index bc412214c7..1c8864a9df 100644
--- a/indra/newview/lldrawpool.h
+++ b/indra/newview/lldrawpool.h
@@ -55,6 +55,7 @@ public:
         // based on fill rate and likelihood to occlude future passes (faster, large occluders first).
         //
         POOL_SKY = 1,
+        POOL_WATEREXCLUSION,
         POOL_WL_SKY,
         POOL_SIMPLE,
         POOL_FULLBRIGHT,
@@ -140,7 +141,7 @@ public:
         PASS_GRASS,
         PASS_FULLBRIGHT,
         PASS_FULLBRIGHT_RIGGED,
-        PASS_INVISIBLE,
+        PASS_INVISIBLE,                         // Formerly, invisiprims.  Now, water exclusion surfaces.
         PASS_INVISIBLE_RIGGED,
         PASS_INVISI_SHINY,
         PASS_INVISI_SHINY_RIGGED,
diff --git a/indra/newview/lldrawpoolwater.cpp b/indra/newview/lldrawpoolwater.cpp
index 53d6e528b6..c27f5ef486 100644
--- a/indra/newview/lldrawpoolwater.cpp
+++ b/indra/newview/lldrawpoolwater.cpp
@@ -236,6 +236,8 @@ void LLDrawPoolWater::renderPostDeferred(S32 pass)
             gGL.getTexUnit(bumpTex2)->bind(tex_b);
         }
 
+        shader->bindTexture(LLShaderMgr::WATER_EXCLUSIONTEX, &gPipeline.mWaterExclusionMask);
+
         // bind reflection texture from RenderTarget
         S32 screentex = shader->enableTexture(LLShaderMgr::WATER_SCREENTEX);
 
@@ -307,30 +309,11 @@ void LLDrawPoolWater::renderPostDeferred(S32 pass)
 
         LLGLDisable cullface(GL_CULL_FACE);
 
-        LLVOWater* water = nullptr;
-        for (LLFace* const& face : mDrawFace)
-        {
-            if (!face) continue;
-            water = static_cast<LLVOWater*>(face->getViewerObject());
-            if (!water) continue;
-
-            if ((bool)edge == (bool)water->getIsEdgePatch())
-            {
-                face->renderIndexed();
-
-                // Note non-void water being drawn, updates required
-                if (!edge)  // SL-16461 remove !LLPipeline::sUseOcclusion check
-                {
-                    sNeedsReflectionUpdate = true;
-                    sNeedsDistortionUpdate = true;
-                }
-            }
-        }
+        pushWaterPlanes(edge);
 
         shader->disableTexture(LLShaderMgr::ENVIRONMENT_MAP, LLTexUnit::TT_CUBE_MAP);
         shader->disableTexture(LLShaderMgr::WATER_SCREENTEX);
         shader->disableTexture(LLShaderMgr::BUMP_MAP);
-        shader->disableTexture(LLShaderMgr::WATER_REFTEX);
 
         // clean up
         gPipeline.unbindDeferredShader(*shader);
@@ -345,6 +328,31 @@ void LLDrawPoolWater::renderPostDeferred(S32 pass)
     gGL.setColorMask(true, false);
 }
 
+void LLDrawPoolWater::pushWaterPlanes(int pass)
+{
+    LLVOWater* water = nullptr;
+    for (LLFace* const& face : mDrawFace)
+    {
+        if (!face)
+            continue;
+        water = static_cast<LLVOWater*>(face->getViewerObject());
+        if (!water)
+            continue;
+
+        if ((bool)pass == (bool)water->getIsEdgePatch())
+        {
+            face->renderIndexed();
+
+            // Note non-void water being drawn, updates required
+            if (!pass) // SL-16461 remove !LLPipeline::sUseOcclusion check
+            {
+                sNeedsReflectionUpdate = true;
+                sNeedsDistortionUpdate = true;
+            }
+        }
+    }
+}
+
 LLViewerTexture *LLDrawPoolWater::getDebugTexture()
 {
     return LLViewerTextureManager::getFetchedTexture(IMG_SMOKE);
diff --git a/indra/newview/lldrawpoolwater.h b/indra/newview/lldrawpoolwater.h
index f64477a059..7fc9b68bcf 100644
--- a/indra/newview/lldrawpoolwater.h
+++ b/indra/newview/lldrawpoolwater.h
@@ -74,6 +74,8 @@ public:
     void setOpaqueTexture(const LLUUID& opaqueTextureId);
     void setNormalMaps(const LLUUID& normalMapId, const LLUUID& nextNormalMapId);
 
+    void pushWaterPlanes(int pass);
+
 protected:
     void renderOpaqueLegacyWater();
 };
diff --git a/indra/newview/lldrawpoolwaterexclusion.cpp b/indra/newview/lldrawpoolwaterexclusion.cpp
new file mode 100644
index 0000000000..d796bf39bf
--- /dev/null
+++ b/indra/newview/lldrawpoolwaterexclusion.cpp
@@ -0,0 +1,79 @@
+/**
+ * @file lldrawpool.cpp
+ * @brief LLDrawPoolMaterials class implementation
+ * @author Jonathan "Geenz" Goodman
+ *
+ * $LicenseInfo:firstyear=2002&license=viewerlgpl$
+ * Second Life Viewer Source Code
+ * Copyright (C) 2013, Linden Research, Inc.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation;
+ * version 2.1 of the License only.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ *
+ * Linden Research, Inc., 945 Battery Street, San Francisco, CA  94111  USA
+ * $/LicenseInfo$
+ */
+
+#include "llviewerprecompiledheaders.h"
+
+#include "lldrawpoolwaterexclusion.h"
+#include "llviewershadermgr.h"
+#include "pipeline.h"
+#include "llglcommonfunc.h"
+#include "llvoavatar.h"
+#include "lldrawpoolwater.h"
+
+LLDrawPoolWaterExclusion::LLDrawPoolWaterExclusion() : LLRenderPass(LLDrawPool::POOL_WATEREXCLUSION)
+{
+    LL_INFOS("DPInvisible") << "Creating water exclusion draw pool" << LL_ENDL;
+}
+
+
+void LLDrawPoolWaterExclusion::render(S32 pass)
+{                                             // render invisiprims
+    LL_PROFILE_ZONE_SCOPED_CATEGORY_DRAWPOOL; // LL_RECORD_BLOCK_TIME(FTM_RENDER_INVISIBLE);
+
+    if (gPipeline.shadersLoaded())
+    {
+        gDrawColorProgram.bind();
+    }
+
+
+    LLGLDepthTest depth(GL_TRUE);
+    gDrawColorProgram.uniform4f(LLShaderMgr::DIFFUSE_COLOR, 1, 1, 1, 1);
+
+    LLDrawPoolWater* pwaterpool = (LLDrawPoolWater*)gPipeline.getPool(LLDrawPool::POOL_WATER);
+    if (pwaterpool)
+    {
+        // Just treat our water planes as double sided for the purposes of generating the exclusion mask.
+        LLGLDisable cullface(GL_CULL_FACE);
+        pwaterpool->pushWaterPlanes(0);
+
+        // Take care of the edge water tiles.
+        pwaterpool->pushWaterPlanes(1);
+    }
+
+    gDrawColorProgram.uniform4f(LLShaderMgr::DIFFUSE_COLOR, 0, 0, 0, 1);
+
+    static LLStaticHashedString waterSign("waterSign");
+    gDrawColorProgram.uniform1f(waterSign, 1.f);
+
+    pushBatches(LLRenderPass::PASS_INVISIBLE, false, false);
+
+
+    if (gPipeline.shadersLoaded())
+    {
+        gDrawColorProgram.unbind();
+    }
+}
diff --git a/indra/newview/lldrawpoolwaterexclusion.h b/indra/newview/lldrawpoolwaterexclusion.h
new file mode 100644
index 0000000000..e95721a443
--- /dev/null
+++ b/indra/newview/lldrawpoolwaterexclusion.h
@@ -0,0 +1,61 @@
+/**
+ * @file lldrawpoolwaterexclusion.h
+ * @brief LLDrawPoolWaterExclusion class definition
+ * @author Jonathan "Geenz" Goodman
+ *
+ * $LicenseInfo:firstyear=2025&license=viewerlgpl$
+ * Second Life Viewer Source Code
+ * Copyright (C) 2013, Linden Research, Inc.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation;
+ * version 2.1 of the License only.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ *
+ * Linden Research, Inc., 945 Battery Street, San Francisco, CA  94111  USA
+ * $/LicenseInfo$
+ */
+
+#ifndef LL_LLDRAWPOOLWATEREXCLUSION_H
+#define LL_LLDRAWPOOLWATEREXCLUSION_H
+
+#include "v4coloru.h"
+#include "v2math.h"
+#include "v3math.h"
+#include "llvertexbuffer.h"
+#include "lldrawpool.h"
+
+class LLViewerTexture;
+class LLDrawInfo;
+class LLGLSLShader;
+
+class LLDrawPoolWaterExclusion : public LLRenderPass
+{
+public:
+    LLDrawPoolWaterExclusion();
+
+    enum
+    {
+        VERTEX_DATA_MASK = LLVertexBuffer::MAP_VERTEX
+    };
+
+    virtual U32 getVertexDataMask() { return VERTEX_DATA_MASK; }
+
+    virtual void prerender() {}
+
+    virtual void render(S32 pass = 0);
+    virtual void beginRenderPass(S32 pass) {}
+    virtual void endRenderPass(S32 pass) {}
+    virtual S32  getNumPasses() { return 1; }
+};
+
+#endif // LL_LLDRAWPOOLWATEREXCLUSION_H
diff --git a/indra/newview/llviewershadermgr.cpp b/indra/newview/llviewershadermgr.cpp
index 2619bbbfcb..ac4519e593 100644
--- a/indra/newview/llviewershadermgr.cpp
+++ b/indra/newview/llviewershadermgr.cpp
@@ -101,6 +101,7 @@ LLGLSLShader    gReflectionProbeDisplayProgram;
 LLGLSLShader    gCopyProgram;
 LLGLSLShader    gCopyDepthProgram;
 LLGLSLShader    gPBRTerrainBakeProgram;
+LLGLSLShader    gDrawColorProgram;
 
 //object shaders
 LLGLSLShader        gObjectPreviewProgram;
@@ -3355,6 +3356,17 @@ bool LLViewerShaderMgr::loadShadersInterface()
         success = gCopyDepthProgram.createShader();
     }
 
+    if (success)
+    {
+        gDrawColorProgram.mName = "Draw Color Shader";
+        gDrawColorProgram.mShaderFiles.clear();
+        gDrawColorProgram.mShaderFiles.push_back(make_pair("objects/simpleNoAtmosV.glsl", GL_VERTEX_SHADER));
+        gDrawColorProgram.mShaderFiles.push_back(make_pair("objects/simpleColorF.glsl", GL_FRAGMENT_SHADER));
+        gDrawColorProgram.clearPermutations();
+        gDrawColorProgram.mShaderLevel = mShaderLevel[SHADER_OBJECT];
+        success = gDrawColorProgram.createShader();
+    }
+
     if (gSavedSettings.getBOOL("LocalTerrainPaintEnabled"))
     {
         if (success)
diff --git a/indra/newview/llviewershadermgr.h b/indra/newview/llviewershadermgr.h
index b08796025a..6326de9a6b 100644
--- a/indra/newview/llviewershadermgr.h
+++ b/indra/newview/llviewershadermgr.h
@@ -175,6 +175,7 @@ extern LLGLSLShader         gReflectionProbeDisplayProgram;
 extern LLGLSLShader         gCopyProgram;
 extern LLGLSLShader         gCopyDepthProgram;
 extern LLGLSLShader         gPBRTerrainBakeProgram;
+extern LLGLSLShader         gDrawColorProgram;
 
 //output tex0[tc0] - tex1[tc1]
 extern LLGLSLShader         gTwoTextureCompareProgram;
diff --git a/indra/newview/llviewertexturelist.cpp b/indra/newview/llviewertexturelist.cpp
index 7f38642623..0c186c0ed2 100644
--- a/indra/newview/llviewertexturelist.cpp
+++ b/indra/newview/llviewertexturelist.cpp
@@ -266,7 +266,7 @@ void LLViewerTextureList::doPrefetchImages()
         S32 pixel_area = imagesd["area"];
         S32 texture_type = imagesd["type"];
 
-        if(LLViewerTexture::FETCHED_TEXTURE == texture_type || LLViewerTexture::LOD_TEXTURE == texture_type)
+        if((LLViewerTexture::FETCHED_TEXTURE == texture_type || LLViewerTexture::LOD_TEXTURE == texture_type))
         {
             LLViewerFetchedTexture* image = LLViewerTextureManager::getFetchedTexture(uuid, FTT_DEFAULT, MIPMAP_TRUE, LLGLTexture::BOOST_NONE, texture_type);
             if (image)
diff --git a/indra/newview/llvovolume.cpp b/indra/newview/llvovolume.cpp
index 4dba930ed5..4e8932f912 100644
--- a/indra/newview/llvovolume.cpp
+++ b/indra/newview/llvovolume.cpp
@@ -6732,8 +6732,11 @@ U32 LLVolumeGeometryManager::genDrawInfo(LLSpatialGroup* group, U32 mask, LLFace
             { //shiny
                 if (tex->getPrimaryFormat() == GL_ALPHA)
                 { //invisiprim+shiny
-                    registerFace(group, facep, LLRenderPass::PASS_INVISI_SHINY);
-                    registerFace(group, facep, LLRenderPass::PASS_INVISIBLE);
+                    if (!facep->getViewerObject()->isAttachment() && !facep->getViewerObject()->isRiggedMesh())
+                    {
+                        registerFace(group, facep, LLRenderPass::PASS_INVISI_SHINY);
+                        registerFace(group, facep, LLRenderPass::PASS_INVISIBLE);
+                    }
                 }
                 else if (!hud_group)
                 { //deferred rendering
@@ -6769,7 +6772,10 @@ U32 LLVolumeGeometryManager::genDrawInfo(LLSpatialGroup* group, U32 mask, LLFace
             { //not alpha and not shiny
                 if (!is_alpha && tex->getPrimaryFormat() == GL_ALPHA)
                 { //invisiprim
-                    registerFace(group, facep, LLRenderPass::PASS_INVISIBLE);
+                    if (!facep->getViewerObject()->isAttachment() && !facep->getViewerObject()->isRiggedMesh())
+                    {
+                        registerFace(group, facep, LLRenderPass::PASS_INVISIBLE);
+                    }
                 }
                 else if (fullbright || bake_sunlight)
                 { //fullbright
diff --git a/indra/newview/pipeline.cpp b/indra/newview/pipeline.cpp
index f91b054dd7..18dd694246 100644
--- a/indra/newview/pipeline.cpp
+++ b/indra/newview/pipeline.cpp
@@ -431,6 +431,7 @@ void LLPipeline::init()
     stop_glerror();
 
     //create render pass pools
+    getPool(LLDrawPool::POOL_WATEREXCLUSION);
     getPool(LLDrawPool::POOL_ALPHA_PRE_WATER);
     getPool(LLDrawPool::POOL_ALPHA_POST_WATER);
     getPool(LLDrawPool::POOL_SIMPLE);
@@ -673,6 +674,8 @@ void LLPipeline::cleanup()
     // don't delete wl sky pool it was handled above in the for loop
     //delete mWLSkyPool;
     mWLSkyPool = NULL;
+    delete mWaterExclusionPool;
+    mWaterExclusionPool = nullptr;
 
     releaseGLBuffers();
 
@@ -907,6 +910,15 @@ bool LLPipeline::allocateScreenBufferInternal(U32 resX, U32 resY)
 
         mPostMap.allocate(resX, resY, screenFormat);
 
+        // The water exclusion mask needs its own depth buffer so we can take care of the problem of multiple water planes.
+        // Should we ever make water not just a plane, it also aids with that as well as the water planes will be rendered into the mask.
+        // Why do we do this? Because it saves us some janky logic in the exclusion shader when we generate the mask.
+        // Regardless, this should always only be an R8 texture unless we choose to start having multiple kinds of exclusion that 8 bits can't handle.
+        // - Geenz 2025-02-06
+        bool success = mWaterExclusionMask.allocate(resX, resY, GL_R8, true);
+
+        assert(success);
+
         // used to scale down textures
         // See LLViwerTextureList::updateImagesCreateTextures and LLImageGL::scaleDown
         mDownResMap.allocate(1024, 1024, GL_RGBA);
@@ -1166,6 +1178,8 @@ void LLPipeline::releaseGLBuffers()
 
     mSceneMap.release();
 
+    mWaterExclusionMask.release();
+
     mPostMap.release();
 
     mFXAAMap.release();
@@ -1676,6 +1690,10 @@ LLDrawPool *LLPipeline::findPool(const U32 type, LLViewerTexture *tex0)
         poolp = mPBRAlphaMaskPool;
         break;
 
+    case LLDrawPool::POOL_WATEREXCLUSION:
+        poolp = mWaterExclusionPool;
+        break;
+
     default:
         llassert(0);
         LL_ERRS() << "Invalid Pool Type in  LLPipeline::findPool() type=" << type << LL_ENDL;
@@ -4068,6 +4086,8 @@ void LLPipeline::renderGeomDeferred(LLCamera& camera, bool do_occlusion)
     }
 }
 
+// Render all of our geometry that's required after our deferred pass.
+// This is gonna be stuff like alpha, water, etc.
 void LLPipeline::renderGeomPostDeferred(LLCamera& camera)
 {
     LL_PROFILE_ZONE_SCOPED_CATEGORY_DRAWPOOL;
@@ -4084,6 +4104,10 @@ void LLPipeline::renderGeomPostDeferred(LLCamera& camera)
 
     bool done_atmospherics = LLPipeline::sRenderingHUDs; //skip atmospherics on huds
     bool done_water_haze = done_atmospherics;
+    bool done_water_exclusion = false;
+
+    // do water exclusion just before water pass.
+    U32 water_exclusion_pass = LLDrawPool::POOL_WATEREXCLUSION;
 
     // do atmospheric haze just before post water alpha
     U32 atmospherics_pass = LLDrawPool::POOL_ALPHA_POST_WATER;
@@ -4122,6 +4146,12 @@ void LLPipeline::renderGeomPostDeferred(LLCamera& camera)
 
         cur_type = poolp->getType();
 
+        if (cur_type >= water_exclusion_pass && !done_water_exclusion)
+        { // do water exclusion against depth buffer before rendering alpha
+            doWaterExclusionMask();
+            done_water_exclusion = true;
+        }
+
         if (cur_type >= atmospherics_pass && !done_atmospherics)
         { // do atmospherics against depth buffer before rendering alpha
             doAtmospherics();
@@ -5201,6 +5231,17 @@ void LLPipeline::addToQuickLookup( LLDrawPool* new_poolp )
         }
         break;
 
+    case LLDrawPool::POOL_WATEREXCLUSION:
+        if (mWaterExclusionPool)
+        {
+            llassert(0);
+            LL_WARNS() << "LLPipeline::addPool(): Ignoring duplicate Water Exclusion Pool" << LL_ENDL;
+        }
+        else
+        {
+            mWaterExclusionPool = new_poolp;
+        }
+        break;
 
     default:
         llassert(0);
@@ -5323,6 +5364,11 @@ void LLPipeline::removeFromQuickLookup( LLDrawPool* poolp )
         mPBRAlphaMaskPool = NULL;
         break;
 
+    case LLDrawPool::POOL_WATEREXCLUSION:
+        llassert(poolp == mWaterExclusionPool);
+        mWaterExclusionPool = nullptr;
+        break;
+
     default:
         llassert(0);
         LL_WARNS() << "Invalid Pool Type in  LLPipeline::removeFromQuickLookup() type=" << poolp->getType() << LL_ENDL;
@@ -8824,6 +8870,7 @@ void LLPipeline::renderDeferredLighting()
                           LLPipeline::RENDER_TYPE_FULLBRIGHT_ALPHA_MASK,
                           LLPipeline::RENDER_TYPE_TERRAIN,
                           LLPipeline::RENDER_TYPE_WATER,
+                          LLPipeline::RENDER_TYPE_WATEREXCLUSION,
                           END_RENDER_TYPES);
 
         renderGeomPostDeferred(*LLViewerCamera::getInstance());
@@ -8962,6 +9009,8 @@ void LLPipeline::doWaterHaze()
         static LLStaticHashedString above_water_str("above_water");
         haze_shader.uniform1i(above_water_str, sUnderWaterRender ? -1 : 1);
 
+        haze_shader.bindTexture(LLShaderMgr::WATER_EXCLUSIONTEX, &mWaterExclusionMask);
+
         if (LLPipeline::sUnderWaterRender)
         {
             LLGLDepthTest depth(GL_FALSE);
@@ -8992,6 +9041,17 @@ void LLPipeline::doWaterHaze()
     }
 }
 
+void LLPipeline::doWaterExclusionMask()
+{
+    mWaterExclusionMask.bindTarget();
+    glClearColor(1, 1, 1, 1);
+    mWaterExclusionMask.clear();
+    mWaterExclusionPool->render();
+
+    mWaterExclusionMask.flush();
+    glClearColor(0, 0, 0, 0);
+}
+
 void LLPipeline::setupSpotLight(LLGLSLShader& shader, LLDrawable* drawablep)
 {
     //construct frustum
diff --git a/indra/newview/pipeline.h b/indra/newview/pipeline.h
index 5c9b95ef4a..315e38ed8c 100644
--- a/indra/newview/pipeline.h
+++ b/indra/newview/pipeline.h
@@ -337,6 +337,9 @@ public:
     // should be called just before rendering pre-water alpha objects
     void doWaterHaze();
 
+    // Generate the water exclusion surface mask.
+    void doWaterExclusionMask();
+
     void postDeferredGammaCorrect(LLRenderTarget* screen_target);
 
     void generateSunShadow(LLCamera& camera);
@@ -500,6 +503,7 @@ public:
         RENDER_TYPE_AVATAR                      = LLDrawPool::POOL_AVATAR,
         RENDER_TYPE_CONTROL_AV                  = LLDrawPool::POOL_CONTROL_AV, // Animesh
         RENDER_TYPE_TREE                        = LLDrawPool::POOL_TREE,
+        RENDER_TYPE_WATEREXCLUSION              = LLDrawPool::POOL_WATEREXCLUSION,
         RENDER_TYPE_VOIDWATER                   = LLDrawPool::POOL_VOIDWATER,
         RENDER_TYPE_WATER                       = LLDrawPool::POOL_WATER,
         RENDER_TYPE_GLTF_PBR                    = LLDrawPool::POOL_GLTF_PBR,
@@ -714,6 +718,7 @@ public:
     LLRenderTarget          mSpotShadow[2];
 
     LLRenderTarget          mPbrBrdfLut;
+    LLRenderTarget          mWaterExclusionMask;
 
     // copy of the color/depth buffer just before gamma correction
     // for use by SSR
@@ -953,6 +958,7 @@ protected:
     LLDrawPool*                 mWLSkyPool = nullptr;
     LLDrawPool*                 mPBROpaquePool = nullptr;
     LLDrawPool*                 mPBRAlphaMaskPool = nullptr;
+    LLDrawPool*                 mWaterExclusionPool      = nullptr;
 
     // Note: no need to keep an quick-lookup to avatar pools, since there's only one per avatar