From 631419d23c62739f7927593fe7e67b32e1de0723 Mon Sep 17 00:00:00 2001
From: Andrzej Kapolka <drzej.k@gmail.com>
Date: Wed, 22 Oct 2014 18:22:21 -0700
Subject: [PATCH] Tweaks to heightfield conversion.

---
 .../shaders/metavoxel_heightfield_base.vert   | 13 +++---
 .../metavoxels/src/MetavoxelMessages.cpp      | 43 ++++++++++++-------
 2 files changed, 35 insertions(+), 21 deletions(-)

diff --git a/interface/resources/shaders/metavoxel_heightfield_base.vert b/interface/resources/shaders/metavoxel_heightfield_base.vert
index f097426e13..5486f5fa67 100644
--- a/interface/resources/shaders/metavoxel_heightfield_base.vert
+++ b/interface/resources/shaders/metavoxel_heightfield_base.vert
@@ -26,11 +26,14 @@ varying vec4 normal;
 void main(void) {
     // transform and store the normal for interpolation
     vec2 heightCoord = gl_MultiTexCoord0.st;
-    float deltaX = texture2D(heightMap, heightCoord - vec2(heightScale, 0.0)).r -
-        texture2D(heightMap, heightCoord + vec2(heightScale, 0.0)).r;
-    float deltaZ = texture2D(heightMap, heightCoord - vec2(0.0, heightScale)).r -
-        texture2D(heightMap, heightCoord + vec2(0.0, heightScale)).r;
-    normal = normalize(gl_ModelViewMatrix * vec4(deltaX, heightScale, deltaZ, 0.0));
+    vec4 neighborHeights = vec4(texture2D(heightMap, heightCoord - vec2(heightScale, 0.0)).r,
+        texture2D(heightMap, heightCoord + vec2(heightScale, 0.0)).r,
+        texture2D(heightMap, heightCoord - vec2(0.0, heightScale)).r,
+        texture2D(heightMap, heightCoord + vec2(0.0, heightScale)).r);
+    vec4 neighborsZero = step(1.0 / 255.0, neighborHeights);
+    normal = normalize(gl_ModelViewMatrix * vec4(
+        (neighborHeights.x - neighborHeights.y) * neighborsZero.x * neighborsZero.y, heightScale,
+        (neighborHeights.z - neighborHeights.w) * neighborsZero.z * neighborsZero.w, 0.0));
     
     // add the height to the position
     float height = texture2D(heightMap, heightCoord).r;
diff --git a/libraries/metavoxels/src/MetavoxelMessages.cpp b/libraries/metavoxels/src/MetavoxelMessages.cpp
index d9c60f3f12..2d1e03fc69 100644
--- a/libraries/metavoxels/src/MetavoxelMessages.cpp
+++ b/libraries/metavoxels/src/MetavoxelMessages.cpp
@@ -1062,6 +1062,13 @@ int HeightfieldClearFetchVisitor::visit(MetavoxelInfo& info) {
     HeightfieldHeightDataPointer newHeightPointer(new HeightfieldHeightData(contents));
     info.outputValues[0] = AttributeValue(_outputs.at(0), encodeInline<HeightfieldHeightDataPointer>(newHeightPointer));
     
+    // allow a border for what we clear in terms of color/material
+    innerBounds.minimum.x += increment;
+    innerBounds.minimum.z += increment;
+    innerBounds.maximum.x -= increment;
+    innerBounds.maximum.z -= increment;
+    innerOverlap = bounds.getIntersection(innerBounds);
+    
     HeightfieldColorDataPointer colorPointer = info.inputValues.at(1).getInlineValue<HeightfieldColorDataPointer>();
     if (colorPointer) {
         contents = colorPointer->getContents();
@@ -1087,14 +1094,16 @@ int HeightfieldClearFetchVisitor::visit(MetavoxelInfo& info) {
         destY = (innerOverlap.minimum.z - info.minimum.z) * heightScale;
         destWidth = glm::ceil((innerOverlap.maximum.x - innerOverlap.minimum.x) * heightScale);
         destHeight = glm::ceil((innerOverlap.maximum.z - innerOverlap.minimum.z) * heightScale);
-        dest = contents.data() + (destY * size + destX) * DataBlock::COLOR_BYTES;
-        
-        for (int y = 0; y < destHeight; y++, dest += size * DataBlock::COLOR_BYTES) {
-            memset(dest, 0, destWidth * DataBlock::COLOR_BYTES);
+        if (destWidth > 0 && destHeight > 0) {
+            dest = contents.data() + (destY * size + destX) * DataBlock::COLOR_BYTES;
+            
+            for (int y = 0; y < destHeight; y++, dest += size * DataBlock::COLOR_BYTES) {
+                memset(dest, 0, destWidth * DataBlock::COLOR_BYTES);
+            }
+            
+            HeightfieldColorDataPointer newColorPointer(new HeightfieldColorData(contents));
+            info.outputValues[1] = AttributeValue(_outputs.at(1), encodeInline<HeightfieldColorDataPointer>(newColorPointer));
         }
-        
-        HeightfieldColorDataPointer newColorPointer(new HeightfieldColorData(contents));
-        info.outputValues[1] = AttributeValue(_outputs.at(1), encodeInline<HeightfieldColorDataPointer>(newColorPointer));
     }
     
     HeightfieldMaterialDataPointer materialPointer = info.inputValues.at(2).getInlineValue<HeightfieldMaterialDataPointer>();
@@ -1134,16 +1143,18 @@ int HeightfieldClearFetchVisitor::visit(MetavoxelInfo& info) {
         destY = (innerOverlap.minimum.z - info.minimum.z) * heightScale;
         destWidth = glm::ceil((innerOverlap.maximum.x - innerOverlap.minimum.x) * heightScale);
         destHeight = glm::ceil((innerOverlap.maximum.z - innerOverlap.minimum.z) * heightScale);
-        dest = (uchar*)contents.data() + destY * size + destX;
-        
-        for (int y = 0; y < destHeight; y++, dest += size) {
-            memset(dest, 0, destWidth);
+        if (destWidth > 0 && destHeight > 0) {
+            dest = (uchar*)contents.data() + destY * size + destX;
+            
+            for (int y = 0; y < destHeight; y++, dest += size) {
+                memset(dest, 0, destWidth);
+            }
+            
+            clearUnusedMaterials(materials, contents);
+            HeightfieldMaterialDataPointer newMaterialPointer(new HeightfieldMaterialData(contents, materials));
+            info.outputValues[2] = AttributeValue(_outputs.at(2),
+                encodeInline<HeightfieldMaterialDataPointer>(newMaterialPointer));
         }
-        
-        clearUnusedMaterials(materials, contents);
-        HeightfieldMaterialDataPointer newMaterialPointer(new HeightfieldMaterialData(contents, materials));
-        info.outputValues[2] = AttributeValue(_outputs.at(2),
-            encodeInline<HeightfieldMaterialDataPointer>(newMaterialPointer));
     }
     
     return STOP_RECURSION;