From dbc641ce52264d0b5a8e584a726f2df457f26f79 Mon Sep 17 00:00:00 2001
From: Dave Parks <davep@lindenlab.com>
Date: Fri, 16 Dec 2022 12:22:23 -0600
Subject: [PATCH] SL-18861 Optimize away alpha channel on GLTF material
imports.
---
indra/llimage/llimage.cpp | 37 ++++++++++++++++++++++++++++++
indra/llimage/llimage.h | 4 ++++
indra/newview/lltinygltfhelper.cpp | 1 +
3 files changed, 42 insertions(+)
diff --git a/indra/llimage/llimage.cpp b/indra/llimage/llimage.cpp
index 186b01d60c2..031471d1fec 100644
--- a/indra/llimage/llimage.cpp
+++ b/indra/llimage/llimage.cpp
@@ -989,6 +989,43 @@ void LLImageRaw::verticalFlip()
}
+bool LLImageRaw::optimizeAwayAlpha()
+{
+ if (getComponents() == 4)
+ {
+ U8* data = getData();
+ U32 pixels = getWidth() * getHeight();
+
+ // check alpha channel for all 255
+ for (U32 i = 0; i < pixels; ++i)
+ {
+ if (data[i * 4 + 3] != 255)
+ {
+ return false;
+ }
+ }
+
+ // alpha channel is all 255, make a new copy of data without alpha channel
+ U8* new_data = (U8*) ll_aligned_malloc_16(getWidth() * getHeight() * 3);
+
+ for (U32 i = 0; i < pixels; ++i)
+ {
+ U32 di = i * 3;
+ U32 si = i * 4;
+ for (U32 j = 0; j < 3; ++j)
+ {
+ new_data[di+j] = data[si+j];
+ }
+ }
+
+ setDataAndSize(new_data, getWidth(), getHeight(), 3);
+
+ return true;
+ }
+
+ return false;
+}
+
void LLImageRaw::expandToPowerOfTwo(S32 max_dim, bool scale_image)
{
// Find new sizes
diff --git a/indra/llimage/llimage.h b/indra/llimage/llimage.h
index 9e50fd502b6..8f9e1b3c545 100644
--- a/indra/llimage/llimage.h
+++ b/indra/llimage/llimage.h
@@ -208,6 +208,10 @@ class LLImageRaw : public LLImageBase
void clear(U8 r=0, U8 g=0, U8 b=0, U8 a=255);
void verticalFlip();
+
+ // if the alpha channel is all 100% opaque, delete it
+ // returns true if alpha channel was deleted
+ bool optimizeAwayAlpha();
static S32 biasedDimToPowerOfTwo(S32 curr_dim, S32 max_dim = MAX_IMAGE_SIZE);
static S32 expandDimToPowerOfTwo(S32 curr_dim, S32 max_dim = MAX_IMAGE_SIZE);
diff --git a/indra/newview/lltinygltfhelper.cpp b/indra/newview/lltinygltfhelper.cpp
index 838524e9100..611911014ac 100644
--- a/indra/newview/lltinygltfhelper.cpp
+++ b/indra/newview/lltinygltfhelper.cpp
@@ -160,6 +160,7 @@ LLImageRaw * LLTinyGLTFHelper::getTexture(const std::string & folder, const tiny
name = image->name;
rawImage = new LLImageRaw(&image->image[0], image->width, image->height, image->component);
rawImage->verticalFlip();
+ rawImage->optimizeAwayAlpha();
}
return rawImage;
--
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