From 6535ce51fd1e3f2b0efdc650310ec75a7638f6f9 Mon Sep 17 00:00:00 2001
From: Ansariel Hiller <Ansariel@users.noreply.github.com>
Date: Thu, 18 Jul 2024 09:48:24 +0200
Subject: Remove unnecessary code and (re-)add some more compile time constants
 (#2057)

---
 indra/llimage/llimage.h      | 42 +++++++++++++++++++++---------------------
 indra/llimage/llimagej2c.cpp | 22 +++-------------------
 2 files changed, 24 insertions(+), 40 deletions(-)

(limited to 'indra/llimage')

diff --git a/indra/llimage/llimage.h b/indra/llimage/llimage.h
index 42eecbb97c..8b966b8ea3 100644
--- a/indra/llimage/llimage.h
+++ b/indra/llimage/llimage.h
@@ -32,37 +32,37 @@
 #include "llpointer.h"
 #include "lltrace.h"
 
-const S32 MIN_IMAGE_MIP =  2; // 4x4, only used for expand/contract power of 2
-const S32 MAX_IMAGE_MIP = 12; // 4096x4096
+constexpr S32 MIN_IMAGE_MIP =  2; // 4x4, only used for expand/contract power of 2
+constexpr S32 MAX_IMAGE_MIP = 12; // 4096x4096
 
 // *TODO : Use MAX_IMAGE_MIP as max discard level and modify j2c management so that the number
 // of levels is read from the header's file, not inferred from its size.
-const S32 MAX_DISCARD_LEVEL = 5;
+constexpr S32 MAX_DISCARD_LEVEL = 5;
 
 // JPEG2000 size constraints
 // Those are declared here as they are germane to other image constraints used in the viewer
 // and declared right here. Some come from the JPEG2000 spec, some conventions specific to SL.
-const S32 MAX_DECOMPOSITION_LEVELS = 32;    // Number of decomposition levels cannot exceed 32 according to jpeg2000 spec
-const S32 MIN_DECOMPOSITION_LEVELS = 5;     // the SL viewer will *crash* trying to decode images with fewer than 5 decomposition levels (unless image is small that is)
-const S32 MAX_PRECINCT_SIZE = 4096;         // No reason to be bigger than MAX_IMAGE_SIZE
-const S32 MIN_PRECINCT_SIZE = 4;            // Can't be smaller than MIN_BLOCK_SIZE
-const S32 MAX_BLOCK_SIZE = 64;              // Max total block size is 4096, hence 64x64 when using square blocks
-const S32 MIN_BLOCK_SIZE = 4;               // Min block dim is 4 according to jpeg2000 spec
-const S32 MIN_LAYER_SIZE = 2000;            // Size of the first quality layer (after header). Must be > to FIRST_PACKET_SIZE!!
-const S32 MAX_NB_LAYERS = 64;               // Max number of layers we'll entertain in SL (practical limit)
-
-const S32 MIN_IMAGE_SIZE = (1<<MIN_IMAGE_MIP); // 4, only used for expand/contract power of 2
-const S32 MAX_IMAGE_SIZE = (1<<MAX_IMAGE_MIP); // 4096
-const S32 MIN_IMAGE_AREA = MIN_IMAGE_SIZE * MIN_IMAGE_SIZE;
-const S32 MAX_IMAGE_AREA = MAX_IMAGE_SIZE * MAX_IMAGE_SIZE;
-const S32 MAX_IMAGE_COMPONENTS = 8;
-const S32 MAX_IMAGE_DATA_SIZE = MAX_IMAGE_AREA * MAX_IMAGE_COMPONENTS; //4096 * 4096 * 8 = 128 MB
+constexpr S32 MAX_DECOMPOSITION_LEVELS = 32;    // Number of decomposition levels cannot exceed 32 according to jpeg2000 spec
+constexpr S32 MIN_DECOMPOSITION_LEVELS = 5;     // the SL viewer will *crash* trying to decode images with fewer than 5 decomposition levels (unless image is small that is)
+constexpr S32 MAX_PRECINCT_SIZE = 4096;         // No reason to be bigger than MAX_IMAGE_SIZE
+constexpr S32 MIN_PRECINCT_SIZE = 4;            // Can't be smaller than MIN_BLOCK_SIZE
+constexpr S32 MAX_BLOCK_SIZE = 64;              // Max total block size is 4096, hence 64x64 when using square blocks
+constexpr S32 MIN_BLOCK_SIZE = 4;               // Min block dim is 4 according to jpeg2000 spec
+constexpr S32 MIN_LAYER_SIZE = 2000;            // Size of the first quality layer (after header). Must be > to FIRST_PACKET_SIZE!!
+constexpr S32 MAX_NB_LAYERS = 64;               // Max number of layers we'll entertain in SL (practical limit)
+
+constexpr S32 MIN_IMAGE_SIZE = (1<<MIN_IMAGE_MIP); // 4, only used for expand/contract power of 2
+constexpr S32 MAX_IMAGE_SIZE = (1<<MAX_IMAGE_MIP); // 4096
+constexpr S32 MIN_IMAGE_AREA = MIN_IMAGE_SIZE * MIN_IMAGE_SIZE;
+constexpr S32 MAX_IMAGE_AREA = MAX_IMAGE_SIZE * MAX_IMAGE_SIZE;
+constexpr S32 MAX_IMAGE_COMPONENTS = 8;
+constexpr S32 MAX_IMAGE_DATA_SIZE = MAX_IMAGE_AREA * MAX_IMAGE_COMPONENTS; //4096 * 4096 * 8 = 128 MB
 
 // Note!  These CANNOT be changed without modifying simulator code
 // *TODO: change both to 1024 when SIM texture fetching is deprecated
-const S32 FIRST_PACKET_SIZE = 600;
-const S32 MAX_IMG_PACKET_SIZE = 1000;
-const S32 HTTP_PACKET_SIZE = 1496;
+constexpr S32 FIRST_PACKET_SIZE = 600;
+constexpr S32 MAX_IMG_PACKET_SIZE = 1000;
+constexpr S32 HTTP_PACKET_SIZE = 1496;
 
 // Base classes for images.
 // There are two major parts for the image:
diff --git a/indra/llimage/llimagej2c.cpp b/indra/llimage/llimagej2c.cpp
index 5dfd8cd947..29449a5d2e 100644
--- a/indra/llimage/llimagej2c.cpp
+++ b/indra/llimage/llimagej2c.cpp
@@ -275,10 +275,10 @@ S32 LLImageJ2C::calcDataSizeJ2C(S32 w, S32 h, S32 comp, S32 discard_level, F32 r
     // For details about the equation used here, see https://wiki.lindenlab.com/wiki/THX1138_KDU_Improvements#Byte_Range_Study
 
     // Estimate the number of layers. This is consistent with what's done for j2c encoding in LLImageJ2CKDU::encodeImpl().
+    constexpr S32 precision = 8; // assumed bitrate per component channel, might change in future for HDR support
     S32 nb_layers = 1;
-    S32 surface = w*h;
+    const S32 surface = w*h;
     S32 s = 64*64;
-    S32 precision = 8; // assumed bitrate per component channel, might change in future for HDR support
     S32 totalbytes = (S32)(s * comp * precision * rate); // first level computed before loop
     while (surface > s)
     {
@@ -287,27 +287,11 @@ S32 LLImageJ2C::calcDataSizeJ2C(S32 w, S32 h, S32 comp, S32 discard_level, F32 r
         nb_layers++;
         s *= 4;
     }
-    F32 layer_factor =  3.0f * (7 - llclamp(nb_layers,1,6));
 
     totalbytes /= 8; // to bytes
     totalbytes += calcHeaderSizeJ2C();  // header
 
-    // Compute w/pow(2,discard_level) and h/pow(2,discard_level)
-    w >>= discard_level;
-    h >>= discard_level;
-    w = llmax(w, 1);
-    h = llmax(h, 1);
-
-    // Temporary: compute both new and old range and pick one according to the settings TextureNewByteRange
-    // *TODO: Take the old code out once we have enough tests done
-    S32 bytes;
-    S32 new_bytes = (S32) (sqrt((F32)(w*h))*(F32)(comp)*rate*1000.f/layer_factor);
-    S32 old_bytes = (S32)((F32)(w*h*comp)*rate);
-    bytes = (LLImage::useNewByteRange() && (new_bytes < old_bytes) ? new_bytes : old_bytes);
-    bytes = llmax(totalbytes, calcHeaderSizeJ2C());
-    //LL_WARNS() << "calcDataSizeJ2C w-h-c-d-p " << w << "-" << h << "-" << comp << "-" << discard_level << "-" << precision
-    //           << " Pyramid: " << (S32)totalbytes << " LayerFactored: " << new_bytes << " WJCR: " << old_bytes << LL_ENDL;
-    return bytes;
+    return totalbytes;
 }
 
 S32 LLImageJ2C::calcHeaderSize()
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