From 66722ac100d2f5ee69edfec22a20ad8dce5b44a1 Mon Sep 17 00:00:00 2001
From: asrael <asrael@pxl8.org>
Date: Sat, 15 Nov 2025 14:23:53 -0600
Subject: [PATCH] optimize texture sampling

---
 demo/mod/worldgen.fnl |  2 +-
 pxl8.sh               |  7 +++++--
 src/pxl8_gfx.c        | 13 ++++++++-----
 3 files changed, 14 insertions(+), 8 deletions(-)

diff --git a/demo/mod/worldgen.fnl b/demo/mod/worldgen.fnl
index a10a8fc..61a1529 100644
--- a/demo/mod/worldgen.fnl
+++ b/demo/mod/worldgen.fnl
@@ -4,7 +4,7 @@
 (var cam-x 1000)
 (var cam-y 64)
 (var cam-z 1000)
-(var cam-yaw 0)
+(var cam-yaw 0.074)
 (var cam-pitch 0)
 (var bob-time 0)
 (var velocity-y 0)
diff --git a/pxl8.sh b/pxl8.sh
index 3096771..adb1612 100755
--- a/pxl8.sh
+++ b/pxl8.sh
@@ -284,6 +284,8 @@ else
     BINDIR="$BINDIR/debug"
 fi
 
+DEP_CFLAGS="-O3 -ffast-math -funroll-loops"
+
 case "$COMMAND" in
     build)
         mkdir -p "$BUILDDIR"
@@ -333,7 +335,8 @@ case "$COMMAND" in
 
         INCLUDES="-Isrc -Ilib -Ilib/microui/src -Ilib/luajit/src -Ilib/linenoise -Ilib/miniz"
         COMPILE_FLAGS="$CFLAGS $INCLUDES"
-        
+        DEP_COMPILE_FLAGS="$DEP_CFLAGS $INCLUDES"
+
         EXECUTABLE="$BINDIR/pxl8"
 
         LIB_SOURCE_FILES="lib/linenoise/linenoise.c lib/microui/src/microui.c lib/miniz/miniz.c"
@@ -376,7 +379,7 @@ case "$COMMAND" in
 
             if [[ "$src_file" -nt "$obj_file" ]]; then
                 NEED_LINK=true
-                compile_source_file "$src_file" "$obj_file" "$COMPILE_FLAGS"
+                compile_source_file "$src_file" "$obj_file" "$DEP_COMPILE_FLAGS"
                 SOURCES_COMPILED="yes"
             fi
         done
diff --git a/src/pxl8_gfx.c b/src/pxl8_gfx.c
index dd7f71b..b3cb16d 100644
--- a/src/pxl8_gfx.c
+++ b/src/pxl8_gfx.c
@@ -810,8 +810,9 @@ void pxl8_3d_clear_zbuffer(pxl8_gfx* gfx) {
     i32 count = gfx->zbuffer_width * gfx->zbuffer_height;
     const f32 far_z = 1e30f;
 
+    f32* ptr = gfx->zbuffer;
     for (i32 i = 0; i < count; i++) {
-        gfx->zbuffer[i] = far_z;
+        ptr[i] = far_z;
     }
 }
 
@@ -1002,11 +1003,13 @@ static inline u32 pxl8_sample_texture(pxl8_gfx* gfx, u32 texture_id, f32 u, f32
         return 0;
     }
 
-    u = u - floorf(u);
-    v = v - floorf(v);
+    i32 tex_u = (i32)(u * entry->w);
+    i32 tex_v = (i32)(v * entry->h);
 
-    i32 tx = (i32)(u * entry->w) % entry->w;
-    i32 ty = (i32)(v * entry->h) % entry->h;
+    i32 tx = tex_u % entry->w;
+    if (tx < 0) tx += entry->w;
+    i32 ty = tex_v % entry->h;
+    if (ty < 0) ty += entry->h;
 
     i32 atlas_x = entry->x + tx;
     i32 atlas_y = entry->y + ty;