sokol_debugtext.h: fix texturing artefacts by spacing out character cells in font texture

1 files changed, 12 insertions, 16 deletions

diff --git a/util/sokol_debugtext.h b/util/sokol_debugtext.h
index 574b0af2..3305c0e0 100644
--- a/util/sokol_debugtext.h
+++ b/util/sokol_debugtext.h
@@ -3539,7 +3539,8 @@ typedef struct {
     sdtx_context cur_ctx_id;
     _sdtx_context_t* cur_ctx;   // may be 0!
     _sdtx_context_pool_t context_pool;
-    uint8_t font_pixels[SDTX_MAX_FONTS * 256 * 8 * 8];
+    // NOTE: each char cell is an 8x8 grid at the top left of a 16x16 grid
+    uint8_t font_pixels[SDTX_MAX_FONTS * 256 * 16 * 16];
 } _sdtx_t;
 static _sdtx_t _sdtx;
 
@@ -3870,7 +3871,8 @@ static void _sdtx_unpack_font(const sdtx_font_desc_t* font_desc, uint8_t* out_pi
         for (int line = 0; line < 8; line++) {
             uint8_t bits = *ptr++;
             for (int x = 0; x < 8; x++) {
-                out_pixels[line*256*8 + chr*8 + x] = ((bits>>(7-x)) & 1) ? 0xFF : 0x00;
+                // NOTE: each character cell is an 8x8 grid at the top left of a 16x16 grid
+                out_pixels[line*256*16 + chr*16 + x] = ((bits>>(7-x)) & 1) ? 0xFF : 0x00;
             }
         }
     }
@@ -3937,8 +3939,8 @@ static void _sdtx_setup_common(void) {
     SOKOL_ASSERT(SG_INVALID_ID != _sdtx.shader.id);
 
     /* unpack font data */
-    memset(_sdtx.font_pixels, 0xFF, sizeof(_sdtx.font_pixels));
-    const int unpacked_font_size = 256 * 8 * 8;
+    memset(_sdtx.font_pixels, 0, sizeof(_sdtx.font_pixels));
+    const int unpacked_font_size = (int) (sizeof(_sdtx.font_pixels) / SDTX_MAX_FONTS);
     for (int i = 0; i < SDTX_MAX_FONTS; i++) {
         if (_sdtx.desc.fonts[i].data.ptr) {
             _sdtx_unpack_font(&_sdtx.desc.fonts[i], &_sdtx.font_pixels[i * unpacked_font_size]);
@@ -3948,8 +3950,8 @@ static void _sdtx_setup_common(void) {
     /* create font texture */
     sg_image_desc img_desc;
     _sdtx_clear(&img_desc, sizeof(img_desc));
-    img_desc.width = 256 * 8;
-    img_desc.height = SDTX_MAX_FONTS * 8;
+    img_desc.width = 256 * 16;
+    img_desc.height = SDTX_MAX_FONTS * 16;
     img_desc.pixel_format = SG_PIXELFORMAT_R8;
     img_desc.min_filter = SG_FILTER_NEAREST;
     img_desc.mag_filter = SG_FILTER_NEAREST;
@@ -4081,18 +4083,12 @@ static void _sdtx_render_char(_sdtx_context_t* ctx, uint8_t c) {
         const float y1 = y0 + ctx->glyph_size.y;
 
         // glyph width and heigth in font texture space
-        const uint16_t uvw = 0x10000 / 0x100;
-        const uint16_t uvh = 0x10000 / SDTX_MAX_FONTS;
-        const uint16_t u0 = ((uint16_t)c) * uvw;
-        const uint16_t v0 = ((uint16_t)ctx->cur_font) * uvh;
+        const uint16_t uvw = 0x10000 / (0x100 * 2);
+        const uint16_t uvh = 0x10000 / (SDTX_MAX_FONTS * 2);
+        const uint16_t u0 = ((uint16_t)c) * uvw * 2;
+        const uint16_t v0 = ((uint16_t)ctx->cur_font) * uvh * 2;
         uint16_t u1 = u0 + uvw;
         uint16_t v1 = v0 + uvh;
-        if (u1 == 0x0000) {
-            u1 = 0xFFFF;
-        }
-        if (v1 == 0x0000) {
-            v1 = 0xFFFF;
-        }
         const uint32_t color = ctx->color;
 
         // write 6 vertices