commit ef9331fb7207d479bdb4e56eea56e621ab348ebf
parent 82ead357a7725a67d4451be04df1b9a849a601f4
Author: Connor Thomson <connor@gnufault.org>
Date:   Sun, 18 Oct 2026 18:17:15 -0700

Add TA_DISABLE_BILINEAR_FILTERING flag

Diffstat:
M
Makefile
 | 
16
+++++++++++++++-
M
src/ta_image.c
 | 
18
+++++++++++++++---

2 files changed, 30 insertions(+), 4 deletions(-)
diff --git a/Makefile b/Makefile
@@ -28,6 +28,10 @@ endif
 
 CFLAGS      := -march=$(MARCH) -mtune=$(MARCH) -m$(BITS) $(ARCH_DEFINE) -I$(INCLUDE_DIR) -I$(BUILD_DIR) -std=$(CSTD) $(FLAGS)
 
+ifeq ($(TA_DISABLE_BILINEAR_FILTERING),true)
+CFLAGS += -DTA_DISABLE_BILINEAR_FILTERING
+endif
+
 ARFLAGS     := rcs
 
 SRCS        := $(shell find $(SRC_DIR) -type f -name '*.c')
@@ -59,6 +63,14 @@ $(BUILD_DIR)/%.o: $(SRC_DIR)/%.c | $(BUILD_DIR)
 	mkdir -p $(dir $@)
 	$(CC) $(CFLAGS) -c $< -o $@
 
+TA_IMAGE_FILTER_CONFIG := $(BUILD_DIR)/ta_image_filtering.config
+
+$(TA_IMAGE_FILTER_CONFIG): FORCE | $(BUILD_DIR)
+	@printf '%s\n' '$(if $(filter true,$(TA_DISABLE_BILINEAR_FILTERING)),disabled,enabled)' > $@.tmp
+	@if ! cmp -s $@.tmp $@; then mv $@.tmp $@; else rm $@.tmp; fi
+
+$(BUILD_DIR)/ta_image.o: $(TA_IMAGE_FILTER_CONFIG)
+
 $(BUILD_DIR)/%.o: $(BUILD_DIR)/%.c
 	mkdir -p $(dir $@)
 	$(CC) $(CFLAGS) -c $< -o $@
@@ -69,4 +81,6 @@ $(CONFIG_HEADER): | $(BUILD_DIR)
 clean:
 	rm -rf $(BUILD_DIR)
 
-.PHONY: all clean
+FORCE:
+
+.PHONY: all clean FORCE
diff --git a/src/ta_image.c b/src/ta_image.c
@@ -337,11 +337,16 @@ ta_bool ta_image_draw(const ta_uint8 *data, ta_uint32 length, float x, float y, 
             continue;
         }
 
-        ta_uint64 source_y_position = ((ta_uint64)(2 * (ta_uint64)image_y + 1) * image->height * 128) / pixel_height;
         ta_uint32 source_y0;
         ta_uint32 source_y1;
         ta_uint32 fraction_y;
-     
+
+    #ifdef TA_DISABLE_BILINEAR_FILTERING
+        source_y0  = (ta_uint32)((ta_uint64)image_y * image->height / pixel_height);
+        source_y1  = source_y0;
+        fraction_y = 0;
+    #else
+        ta_uint64 source_y_position = ((ta_uint64)(2 * (ta_uint64)image_y + 1) * image->height * 128) / pixel_height;
         if (source_y_position <= 128) {
             source_y0  = 0;
             source_y1  = 0;
@@ -359,6 +364,7 @@ ta_bool ta_image_draw(const ta_uint8 *data, ta_uint32 length, float x, float y, 
                 source_y1 = source_y0 + 1;
             }
         }
+#endif
 
         for (ta_uint32 image_x = 0; image_x < pixel_width; image_x++) {
             ta_uint64 screen_x = (ta_uint64)pixel_x + image_x;
@@ -367,11 +373,16 @@ ta_bool ta_image_draw(const ta_uint8 *data, ta_uint32 length, float x, float y, 
                 continue;
             }
 
-            ta_uint64 source_x_position = ((ta_uint64)(2 * (ta_uint64)image_x + 1) * image->width * 128) / pixel_width;
             ta_uint32 source_x0;
             ta_uint32 source_x1;
             ta_uint32 fraction_x;
 
+#ifdef TA_DISABLE_BILINEAR_FILTERING
+            source_x0  = (ta_uint32)((ta_uint64)image_x * image->width / pixel_width);
+            source_x1  = source_x0;
+            fraction_x = 0;
+#else
+            ta_uint64 source_x_position = ((ta_uint64)(2 * (ta_uint64)image_x + 1) * image->width * 128) / pixel_width;
             if (source_x_position <= 128) {
                 source_x0  = 0;
                 source_x1  = 0;
@@ -389,6 +400,7 @@ ta_bool ta_image_draw(const ta_uint8 *data, ta_uint32 length, float x, float y, 
                     source_x1 = source_x0 + 1;
                 }
             }
+#endif
 
             ta_uint32 weight_x0 = 256 - fraction_x;
             ta_uint32 weight_y0 = 256 - fraction_y;