Fixed glyph hash collisions with fallback fonts

CMakeLists.txt

@@ -125,6 +125,7 @@ endif()
 
 add_library(${sdl3_ttf_target_name}
     src/SDL_hashtable.c
+    src/SDL_hashtable_ttf.c
     src/SDL_gpu_textengine.c
     src/SDL_renderer_textengine.c
     src/SDL_surface_textengine.c

VisualC/SDL_ttf.vcxproj

@@ -380,6 +380,7 @@
     <ClCompile Include="..\external\harfbuzz\src\hb-wasm-shape.cc" />
     <ClCompile Include="..\src\SDL_gpu_textengine.c" />
     <ClCompile Include="..\src\SDL_hashtable.c" />
+    <ClCompile Include="..\src\SDL_hashtable_ttf.c" />
     <ClCompile Include="..\src\SDL_renderer_textengine.c" />
     <ClCompile Include="..\src\SDL_surface_textengine.c" />
     <ClCompile Include="..\src\SDL_ttf.c" />
@@ -393,4 +394,4 @@
   <Import Project="$(VCTargetsPath)\Microsoft.Cpp.targets" />
   <ImportGroup Label="ExtensionTargets">
   </ImportGroup>
-</Project>
+</Project>

VisualC/SDL_ttf.vcxproj.filters

@@ -24,6 +24,9 @@
     <ClCompile Include="..\src\SDL_hashtable.c">
       <Filter>Sources</Filter>
     </ClCompile>
+    <ClCompile Include="..\src\SDL_hashtable_ttf.c">
+      <Filter>Sources</Filter>
+    </ClCompile>
     <ClCompile Include="..\src\SDL_renderer_textengine.c">
       <Filter>Sources</Filter>
     </ClCompile>
@@ -415,4 +418,4 @@
       <Filter>x64</Filter>
     </CustomBuild>
   </ItemGroup>
-</Project>
+</Project>

Xcode/SDL_ttf.xcodeproj/project.pbxproj

@@ -65,6 +65,8 @@
 		F341242A2D42C44700D6C2B7 /* INSTALL.md in Resources */ = {isa = PBXBuildFile; fileRef = F34124292D42C44700D6C2B7 /* INSTALL.md */; };
 		F341242D2D42C47A00D6C2B7 /* LICENSE.txt in Resources */ = {isa = PBXBuildFile; fileRef = F341242B2D42C47A00D6C2B7 /* LICENSE.txt */; };
 		F341242E2D42C47A00D6C2B7 /* README.md in Resources */ = {isa = PBXBuildFile; fileRef = F341242C2D42C47A00D6C2B7 /* README.md */; };
+		F34125C72D491AA800D6C2B7 /* SDL_hashtable_ttf.h in Headers */ = {isa = PBXBuildFile; fileRef = F34125C52D491AA800D6C2B7 /* SDL_hashtable_ttf.h */; };
+		F34125C82D491AA800D6C2B7 /* SDL_hashtable_ttf.c in Sources */ = {isa = PBXBuildFile; fileRef = F34125C62D491AA800D6C2B7 /* SDL_hashtable_ttf.c */; };
 		F34400402D4033CE003F26D7 /* SDL3.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = F344003F2D4033CE003F26D7 /* SDL3.framework */; };
 		F344FFBF2D3EB53C003F26D7 /* SDL_gpu_textengine.c in Sources */ = {isa = PBXBuildFile; fileRef = F344FFBE2D3EB53C003F26D7 /* SDL_gpu_textengine.c */; };
 		F3696FE4278F7107003A7F94 /* sdf.c in Sources */ = {isa = PBXBuildFile; fileRef = F3696FE3278F7107003A7F94 /* sdf.c */; };
@@ -191,6 +193,8 @@
 		F341242B2D42C47A00D6C2B7 /* LICENSE.txt */ = {isa = PBXFileReference; lastKnownFileType = text; name = LICENSE.txt; path = ../LICENSE.txt; sourceTree = SOURCE_ROOT; };
 		F341242C2D42C47A00D6C2B7 /* README.md */ = {isa = PBXFileReference; lastKnownFileType = net.daringfireball.markdown; name = README.md; path = ../README.md; sourceTree = SOURCE_ROOT; };
 		F341242F2D42C49B00D6C2B7 /* INSTALL.md */ = {isa = PBXFileReference; lastKnownFileType = net.daringfireball.markdown; path = INSTALL.md; sourceTree = "<group>"; };
+		F34125C52D491AA800D6C2B7 /* SDL_hashtable_ttf.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = SDL_hashtable_ttf.h; sourceTree = "<group>"; };
+		F34125C62D491AA800D6C2B7 /* SDL_hashtable_ttf.c */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.c; path = SDL_hashtable_ttf.c; sourceTree = "<group>"; };
 		F344003F2D4033CE003F26D7 /* SDL3.framework */ = {isa = PBXFileReference; lastKnownFileType = wrapper.framework; path = SDL3.framework; sourceTree = "<group>"; };
 		F344FFBE2D3EB53C003F26D7 /* SDL_gpu_textengine.c */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.c; path = SDL_gpu_textengine.c; sourceTree = "<group>"; };
 		F3696FE3278F7107003A7F94 /* sdf.c */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.c; name = sdf.c; path = ../external/freetype/src/sdf/sdf.c; sourceTree = "<group>"; };
@@ -335,6 +339,8 @@
 				F344FFBE2D3EB53C003F26D7 /* SDL_gpu_textengine.c */,
 				F3F7BDF12CB6FD6700C984AF /* SDL_hashtable.h */,
 				F3F7BDF22CB6FD6700C984AF /* SDL_hashtable.c */,
+				F34125C52D491AA800D6C2B7 /* SDL_hashtable_ttf.h */,
+				F34125C62D491AA800D6C2B7 /* SDL_hashtable_ttf.c */,
 				F3F7BDF32CB6FD6700C984AF /* SDL_renderer_textengine.c */,
 				F3F7BDF42CB6FD6700C984AF /* SDL_surface_textengine.c */,
 				F567D67A01CD962A01F3E8B9 /* SDL_ttf.c */,
@@ -500,6 +506,7 @@
 			buildActionMask = 2147483647;
 			files = (
 				F3F7BDF72CB6FD6700C984AF /* SDL_hashtable.h in Headers */,
+				F34125C72D491AA800D6C2B7 /* SDL_hashtable_ttf.h in Headers */,
 				F3F7BDF82CB6FD6700C984AF /* stb_rect_pack.h in Headers */,
 				BE48FD5F07AFA17000BB41DA /* SDL_ttf.h in Headers */,
 				F33F083D2CC41C810062C26D /* SDL_textengine.h in Headers */,
@@ -648,6 +655,7 @@
 				F384BDBF261EC7650028A248 /* hb-buffer.cc in Sources */,
 				F384BD83261EC7650028A248 /* hb-shaper.cc in Sources */,
 				F384BCD4261EC2BE0028A248 /* type42.c in Sources */,
+				F34125C82D491AA800D6C2B7 /* SDL_hashtable_ttf.c in Sources */,
 				F384BDEF261EC7650028A248 /* hb-face.cc in Sources */,
 				F384BCDF261EC2CF0028A248 /* winfnt.c in Sources */,
 				F384BC2F261EC1710028A248 /* cff.c in Sources */,

src/SDL_gpu_textengine.c

@@ -23,6 +23,7 @@
 #include <SDL3_ttf/SDL_ttf.h>
 
 #include "SDL_hashtable.h"
+#include "SDL_hashtable_ttf.h"
 
 #define ATLAS_TEXTURE_SIZE 1024
 
@@ -387,9 +388,9 @@ static bool UpdateGlyph(SDL_GPUDevice *device, AtlasGlyph *glyph, SDL_Surface *s
     return true;
 }
 
-static bool AddGlyphToFont(TTF_GPUTextEngineFontData *fontdata, Uint32 glyph_index, AtlasGlyph *glyph)
+static bool AddGlyphToFont(TTF_GPUTextEngineFontData *fontdata, TTF_Font *glyph_font, Uint32 glyph_index, AtlasGlyph *glyph)
 {
-    if (!SDL_InsertIntoHashTable(fontdata->glyphs, (const void *)(uintptr_t)glyph_index, glyph)) {
+    if (!SDL_InsertIntoGlyphHashTable(fontdata->glyphs, glyph_font, glyph_index, glyph)) {
         return false;
     }
     return true;
@@ -411,12 +412,13 @@ static bool ResolveMissingGlyphs(TTF_GPUTextEngineData *enginedata, AtlasTexture
                 return false;
             }
 
-            if (!AddGlyphToFont(fontdata, ops[missing[i].id].copy.glyph_index, glyph)) {
+            TTF_DrawOperation *op = &ops[missing[i].id];
+            if (!AddGlyphToFont(fontdata, op->copy.glyph_font, op->copy.glyph_index, glyph)) {
                 ReleaseGlyph(glyph);
                 return false;
             }
 
-            ops[missing[i].id].copy.reserved = glyph;
+            op->copy.reserved = glyph;
 
             // Remove this from the missing entries
             --num_missing;
@@ -447,12 +449,13 @@ static bool ResolveMissingGlyphs(TTF_GPUTextEngineData *enginedata, AtlasTexture
             return false;
         }
 
-        if (!AddGlyphToFont(fontdata, ops[missing[i].id].copy.glyph_index, glyph)) {
+        TTF_DrawOperation *op = &ops[missing[i].id];
+        if (!AddGlyphToFont(fontdata, op->copy.glyph_font, op->copy.glyph_index, glyph)) {
             ReleaseGlyph(glyph);
             return false;
         }
 
-        ops[missing[i].id].copy.reserved = glyph;
+        op->copy.reserved = glyph;
     }
 
     if (all_packed) {
@@ -496,7 +499,7 @@ static bool CreateMissingGlyphs(TTF_GPUTextEngineData *enginedata, TTF_GPUTextEn
         goto done;
     }
 
-    checked = SDL_CreateHashTable(NULL, 4, SDL_HashID, SDL_KeyMatchID, NULL, false, false);
+    checked = SDL_CreateGlyphHashTable(NULL);
     if (!checked) {
         goto done;
     }
@@ -507,10 +510,10 @@ static bool CreateMissingGlyphs(TTF_GPUTextEngineData *enginedata, TTF_GPUTextEn
         if (op->cmd == TTF_DRAW_COMMAND_COPY && !op->copy.reserved) {
             TTF_Font *glyph_font = op->copy.glyph_font;
             Uint32 glyph_index = op->copy.glyph_index;
-            if (SDL_FindInHashTable(checked, (const void *)(uintptr_t)glyph_index, NULL)) {
+            if (SDL_FindInGlyphHashTable(checked, glyph_font, glyph_index, NULL)) {
                 continue;
             }
-            if (!SDL_InsertIntoHashTable(checked, (const void *)(uintptr_t)glyph_index, NULL)) {
+            if (!SDL_InsertIntoGlyphHashTable(checked, glyph_font, glyph_index, NULL)) {
                 goto done;
             }
 
@@ -553,7 +556,7 @@ static bool CreateMissingGlyphs(TTF_GPUTextEngineData *enginedata, TTF_GPUTextEn
     for (int i = 0; i < num_ops; ++i) {
         TTF_DrawOperation *op = &ops[i];
         if (op->cmd == TTF_DRAW_COMMAND_COPY && !op->copy.reserved) {
-            if (!SDL_FindInHashTable(fontdata->glyphs, (const void *)(uintptr_t)op->copy.glyph_index, (const void **)&op->copy.reserved)) {
+            if (!SDL_FindInGlyphHashTable(fontdata->glyphs, op->copy.glyph_font, op->copy.glyph_index, (const void **)&op->copy.reserved)) {
                 // Something is very wrong...
                 goto done;
             }
@@ -563,7 +566,7 @@ static bool CreateMissingGlyphs(TTF_GPUTextEngineData *enginedata, TTF_GPUTextEn
     result = true;
 
 done:
-    SDL_DestroyHashTable(checked);
+    SDL_DestroyGlyphHashTable(checked);
     if (surfaces) {
         for (int i = 0; i < num_ops; ++i) {
             SDL_DestroySurface(surfaces[i]);
@@ -747,7 +750,7 @@ static TTF_GPUTextEngineTextData *CreateTextData(TTF_GPUTextEngineData *engineda
 
         ++num_glyphs;
 
-        if (!SDL_FindInHashTable(fontdata->glyphs, (const void *)(uintptr_t)op->copy.glyph_index, (const void **)&op->copy.reserved)) {
+        if (!SDL_FindInGlyphHashTable(fontdata->glyphs, op->copy.glyph_font, op->copy.glyph_index, (const void **)&op->copy.reserved)) {
             ++num_missing;
         }
     }
@@ -791,17 +794,15 @@ static void DestroyFontData(TTF_GPUTextEngineFontData *data)
 {
     if (data) {
         if (data->glyphs) {
-            SDL_DestroyHashTable(data->glyphs);
+            SDL_DestroyGlyphHashTable(data->glyphs);
         }
         SDL_free(data);
     }
 }
 
-static void NukeGlyph(const void *key, const void *value, void *unused)
+static void NukeGlyph(const void *value)
 {
     AtlasGlyph *glyph = (AtlasGlyph *)value;
-    (void)key;
-    (void)unused;
     ReleaseGlyph(glyph);
 }
 
@@ -813,7 +814,7 @@ static TTF_GPUTextEngineFontData *CreateFontData(TTF_GPUTextEngineData *engineda
     }
     data->font = font;
     data->generation = font_generation;
-    data->glyphs = SDL_CreateHashTable(NULL, 4, SDL_HashID, SDL_KeyMatchID, NukeGlyph, false, false);
+    data->glyphs = SDL_CreateGlyphHashTable(NukeGlyph);
     if (!data->glyphs) {
         DestroyFontData(data);
         return NULL;

src/SDL_hashtable_ttf.c

@@ -0,0 +1,82 @@
+/*
+  SDL_ttf:  A companion library to SDL for working with TrueType (tm) fonts
+  Copyright (C) 2001-2025 Sam Lantinga <[email protected]>
+
+  This software is provided 'as-is', without any express or implied
+  warranty.  In no event will the authors be held liable for any damages
+  arising from the use of this software.
+
+  Permission is granted to anyone to use this software for any purpose,
+  including commercial applications, and to alter it and redistribute it
+  freely, subject to the following restrictions:
+
+  1. The origin of this software must not be misrepresented; you must not
+     claim that you wrote the original software. If you use this software
+     in a product, an acknowledgment in the product documentation would be
+     appreciated but is not required.
+  2. Altered source versions must be plainly marked as such, and must not be
+     misrepresented as being the original software.
+  3. This notice may not be removed or altered from any source distribution.
+*/
+#include <SDL3_ttf/SDL_ttf.h>
+
+#include "SDL_hashtable.h"
+#include "SDL_hashtable_ttf.h"
+
+typedef struct GlyphHashtableKey {
+    TTF_Font *font;
+    Uint32 glyph_index;
+} GlyphHashtableKey;
+
+static Uint32 SDL_HashGlyphHashtableKey(const void *key, void *unused)
+{
+    (void)unused;
+    return SDL_murmur3_32(key, sizeof(GlyphHashtableKey), 0);
+}
+
+static bool SDL_KeyMatchGlyphHashtableKey(const void *a, const void *b, void *unused)
+{
+    (void)unused;
+    GlyphHashtableKey *A = (GlyphHashtableKey *)a;
+    GlyphHashtableKey *B = (GlyphHashtableKey *)b;
+    return (A->font == B->font && A->glyph_index == B->glyph_index);
+}
+
+static void SDL_NukeFreeGlyphHashtableKey(const void *key, const void *value, void *data)
+{
+    SDL_GlyphHashTable_NukeFn nukefn = (SDL_GlyphHashTable_NukeFn)data;
+
+    if (nukefn) {
+        nukefn(value);
+    }
+    SDL_free((void *)key);
+}
+
+SDL_HashTable *SDL_CreateGlyphHashTable(SDL_GlyphHashTable_NukeFn nukefn)
+{
+    const int num_buckets = 4; // FIXME: Is this a good value?
+    return SDL_CreateHashTable(nukefn, num_buckets, SDL_HashGlyphHashtableKey, SDL_KeyMatchGlyphHashtableKey, SDL_NukeFreeGlyphHashtableKey, false, false);
+}
+
+bool SDL_InsertIntoGlyphHashTable(SDL_HashTable *table, TTF_Font *font, Uint32 glyph_index, const void *value)
+{
+    GlyphHashtableKey *key = (GlyphHashtableKey *)SDL_calloc(1, sizeof(*key));
+    key->font = font;
+    key->glyph_index = glyph_index;
+    return SDL_InsertIntoHashTable(table, key, value);
+}
+
+bool SDL_FindInGlyphHashTable(SDL_HashTable *table, TTF_Font *font, Uint32 glyph_index, const void **value)
+{
+    GlyphHashtableKey key;
+    SDL_zero(key);
+    key.font = font;
+    key.glyph_index = glyph_index;
+    return SDL_FindInHashTable(table, &key, value);
+}
+
+void SDL_DestroyGlyphHashTable(SDL_HashTable *table)
+{
+    SDL_DestroyHashTable(table);
+}
+

src/SDL_hashtable_ttf.h

@@ -0,0 +1,28 @@
+/*
+  SDL_ttf:  A companion library to SDL for working with TrueType (tm) fonts
+  Copyright (C) 2001-2025 Sam Lantinga <[email protected]>
+
+  This software is provided 'as-is', without any express or implied
+  warranty.  In no event will the authors be held liable for any damages
+  arising from the use of this software.
+
+  Permission is granted to anyone to use this software for any purpose,
+  including commercial applications, and to alter it and redistribute it
+  freely, subject to the following restrictions:
+
+  1. The origin of this software must not be misrepresented; you must not
+     claim that you wrote the original software. If you use this software
+     in a product, an acknowledgment in the product documentation would be
+     appreciated but is not required.
+  2. Altered source versions must be plainly marked as such, and must not be
+     misrepresented as being the original software.
+  3. This notice may not be removed or altered from any source distribution.
+*/
+
+typedef void (*SDL_GlyphHashTable_NukeFn)(const void *value);
+
+extern SDL_HashTable *SDL_CreateGlyphHashTable(SDL_GlyphHashTable_NukeFn nukefn);
+extern bool SDL_InsertIntoGlyphHashTable(SDL_HashTable *table, TTF_Font *font, Uint32 glyph_index, const void *value);
+extern  bool SDL_FindInGlyphHashTable(SDL_HashTable *table, TTF_Font *font, Uint32 glyph_index, const void **value);
+extern void SDL_DestroyGlyphHashTable(SDL_HashTable *table);
+