set resampler for sfx channels, remove alsoft config (#995)

* report used resampler in I_InitSound()

* set resampler for sfx channels, remove `alsoft` config

---------

Co-authored-by: Roman Fomin <rfomin@gmail.com>

CMakeLists.txt

@@ -85,7 +85,6 @@ configure_file(config.h.in config.h)
 if(WIN32)
     install(FILES COPYING DESTINATION .)
     install(FILES README.md DESTINATION .)
-    install(FILES data/alsoft DESTINATION . RENAME alsoft.ini)
     install(DIRECTORY docs/ DESTINATION docs)
     install(DIRECTORY examples/ DESTINATION docs/examples)
     install(DIRECTORY autoload/ DESTINATION autoload)
@@ -95,7 +94,6 @@ if(WIN32)
 else()
     install(FILES COPYING DESTINATION "share/doc/${PROJECT_SHORTNAME}")
     install(FILES README.md DESTINATION "share/doc/${PROJECT_SHORTNAME}")
-    install(FILES data/alsoft DESTINATION "share/${PROJECT_SHORTNAME}" RENAME alsoft.conf)
     install(DIRECTORY autoload/ DESTINATION "share/${PROJECT_SHORTNAME}/autoload")
     if(EXISTS "${CMAKE_SOURCE_DIR}/docs")
         install(DIRECTORY docs/ DESTINATION "share/doc/${PROJECT_SHORTNAME}")

data/alsoft

@@ -1,3 +0,0 @@
-# OpenAL configuration. More options at
-# https://github.com/kcat/openal-soft/blob/master/alsoftrc.sample
-resampler = linear

src/i_oalmusic.h

@@ -34,4 +34,4 @@ typedef uint32_t (*callback_func_t)(byte *buffer, uint32_t buffer_samples);
 void I_OAL_HookMusic(callback_func_t callback_func);
 void I_OAL_SetGain(float gain);
 
-#endif
+#endif

src/i_sound.c

@@ -22,6 +22,7 @@
 
 #include "al.h"
 #include "alc.h"
+#include "alext.h"
 
 #include "doomstat.h"
 #include "i_sndfile.h"
@@ -521,6 +522,69 @@ void I_ShutdownSound(void)
     snd_init = false;
 }
 
+// C doesn't allow casting between function and non-function pointer types, so
+// with C99 we need to use a union to reinterpret the pointer type. Pre-C99
+// still needs to use a normal cast and live with the warning (C++ is fine with
+// a regular reinterpret_cast).
+#if __STDC_VERSION__ >= 199901L
+#define FUNCTION_CAST(T, ptr) (union{void *p; T f;}){ptr}.f
+#else
+#define FUNCTION_CAST(T, ptr) (T)(ptr)
+#endif
+
+char *snd_resampler;
+
+static void SetResampler(void)
+{
+    LPALGETSTRINGISOFT alGetStringiSOFT = NULL;
+    ALint i, num_resamplers, def_resampler;
+
+    if (!alIsExtensionPresent("AL_SOFT_source_resampler"))
+    {
+        printf(" Resampler info not available!\n");
+        return;
+    }
+
+    alGetStringiSOFT = FUNCTION_CAST(LPALGETSTRINGISOFT, alGetProcAddress("alGetStringiSOFT"));
+
+    if (!alGetStringiSOFT)
+    {
+        fprintf(stderr, "I_SetResampler: alGetStringiSOFT() is not avaible.\n");
+        return;
+    }
+
+    num_resamplers = alGetInteger(AL_NUM_RESAMPLERS_SOFT);
+    def_resampler = alGetInteger(AL_DEFAULT_RESAMPLER_SOFT);
+
+    if (!num_resamplers)
+    {
+        printf(" No resamplers found!\n");
+        return;
+    }
+
+    for (i = 0; i < num_resamplers; ++i)
+    {
+        if (!strcasecmp(snd_resampler, alGetStringiSOFT(AL_RESAMPLER_NAME_SOFT, i)))
+        {
+            def_resampler = i;
+            break;
+        }
+    }
+    if (i == num_resamplers)
+    {
+        printf(" Failed to find resampler: '%s'.\n", snd_resampler);
+        return;
+    }
+
+    for (i = 0; i < MAX_CHANNELS; ++i)
+    {
+        alSourcei(openal_sources[i], AL_SOURCE_RESAMPLER_SOFT, def_resampler);
+    }
+
+    printf(" Using '%s' resampler.\n",
+           alGetStringiSOFT(AL_RESAMPLER_NAME_SOFT, def_resampler));
+}
+
 // [FG] add links for likely missing sounds
 
 struct {
@@ -591,6 +655,8 @@ void I_InitSound(void)
     openal_sources = malloc(MAX_CHANNELS * sizeof(*openal_sources));
     alGenSources(MAX_CHANNELS, openal_sources);
 
+    SetResampler();
+
     I_AtExit(I_ShutdownSound, true);
 
     snd_init = true;

src/m_misc.c

@@ -97,6 +97,7 @@ extern int winmm_chorus_level;
 #endif
 extern int opl_gain;
 extern int midi_player_menu;
+extern char *snd_resampler;
 extern boolean demobar;
 extern boolean smoothlight;
 extern boolean brightmaps;
@@ -406,6 +407,13 @@ default_t defaults[] = {
     "number of sound effects handled simultaneously"
   },
 
+  {
+    "snd_resampler",
+    (config_t *) &snd_resampler, NULL,
+    {.s = "linear"}, {0}, string, ss_gen, wad_no,
+    "OpenAL resampler (\"nearest\", \"linear\"(default), \"cubic\")"
+  },
+
   // [FG] music backend
   {
     "midi_player",