sdf

sdl_gpu.cm

@@ -1247,7 +1247,7 @@ function _render_text(cmd_buffer, pass, drawable, camera, target) {
   // staef font has 'texture' property which is pixel blob + dims. We need to upload it to GPU if not already.
   var font_tex = _get_font_texture(font, is_sdf)
   
-  pass.bind_fragment_samplers(0, [{texture: font_tex, sampler: is_sdf ? _sampler_linear : _sampler_nearest}])
+  pass.bind_fragment_samplers(0, [{texture: font_tex, sampler: _sampler_nearest}])
   cmd_buffer.push_vertex_uniform_data(0, proj)
   pass.draw_indexed(num_indices, 1, 0, 0, 0)
 }

staef.c

@@ -11,6 +11,9 @@
 #include <stdlib.h>
 #include <string.h>
 
+#define MSDF_IMPLEMENTATION
+#include "msdf.h"
+
 #define STB_TRUETYPE_IMPLEMENTATION
 #define STB_TRUETYPE_NO_STDIO
 #include "stb_truetype.h"
@@ -113,7 +116,7 @@ struct sFont *MakeFont(void *ttf_buffer, size_t len, int height, int is_sdf) {
     int row_height = 0;
     int pad = 5; // padding for SDF
     float onedge_value = 127.5f; // 128ish
-    float pixel_dist_scale = 32.0f; // Distance field range
+    float pixel_dist_scale = 150.f; // Distance field range
 
     for (unsigned char c = 32; c < 127; c++) {
       int glyph_index = c - 29; // Simple ASCII mapping? verify if font has proper map
@@ -124,7 +127,14 @@ struct sFont *MakeFont(void *ttf_buffer, size_t len, int height, int is_sdf) {
       int width, height, xoff, yoff;
       unsigned char *sdf = stbtt_GetGlyphSDF(&fontinfo, scale, g, pad, (unsigned char)onedge_value, pixel_dist_scale, &width, &height, &xoff, &yoff);
       
-      if (!sdf) continue;
+      if (!sdf) {
+        // Handle invisible characters (space)
+        int advance, lsb;
+        stbtt_GetGlyphHMetrics(&fontinfo, g, &advance, &lsb);
+        newfont->Characters[c].advance = advance * scale;
+        // Keep quad/uv as 0
+        continue;
+      }
 
       if (x + width + 1 > packsize) {
         x = 0;
@@ -135,7 +145,6 @@ struct sFont *MakeFont(void *ttf_buffer, size_t len, int height, int is_sdf) {
       if (y + height + 1 > packsize) {
         // Out of space
         free(sdf);
-        // Continue or break? Missing chars better than crash
         continue;
       }
 
@@ -151,15 +160,36 @@ struct sFont *MakeFont(void *ttf_buffer, size_t len, int height, int is_sdf) {
       // Store character info
       rect uv;
       uv.x = (float)x / packsize;
-      uv.y = (float)y / packsize;
+      uv.y = (float)(y + height) / packsize; // Bottom (Top of glyph in SDF?)
+      // To match bitmap path which produces UPSIDE DOWN results if not flipped:
+      // Bitmap path: uv.h = Negative.
+      // So UVs are (y1, y0). (Top Texture is at Bottom vertex).
+      // Here we want to match that.
+      // Top Vertex (v0) should get Bottom Texture.
+      // Bottom Vertex (v1) should get Top Texture.
+      
+      // Let's make uv.h negative.
+      // Top Texture is at 'y'. Bottom Texture is at 'y+height'.
+      // uv.y = (y+height)/size.
+      // uv.h = -height/size.
+      // v0 (Top Vert) = uv.y = y+height (Bottom Tex).
+      // v1 (Bottom Vert) = uv.y + uv.h = y (Top Tex).
+      // This flips the texture on Y.
+      
       uv.w = (float)width / packsize;
-      uv.h = (float)height / packsize;
+      uv.h = -(float)height / packsize;
       newfont->Characters[c].uv = uv;
 
       rect quad;
       quad.x = (float)xoff;
-      quad.y = (float)yoff; 
-      quad.w = (float)width; // Includes padding
+      // Bitmap path: quad.y = -yoff2. (Bottom in Y-Up).
+      // SDF path: yoff is Top in Y-Down (-Top in Y-Up).
+      // height is height.
+      // We want Bottom in Y-Up.
+      // Bottom = - (yoff + height).
+      
+      quad.y = (float)(-yoff - height);
+      quad.w = (float)width;
       quad.h = (float)height;
       newfont->Characters[c].quad = quad;