pd-3ds: Add sysfont loader

- add support for Alpha only textures in rendering

backends/3ds/source/pd-3ds.cpp

@@ -22,10 +22,106 @@ OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 SOFTWARE.
  */
 
+#include <3ds.h>
+
 #include <palladium>
 #include <pd-3ds.hpp>
 
 namespace PD {
+PD::Li::Font::Ref LoadSystemFont() {
+  TT::Scope st("LI_SystemFont");  // Trace loading time
+  Li::Font::Ref ret = Li::Font::New();
+  fontEnsureMapped();  // Call this to be sure the font is mapped
+  // Get some const references for system font loading
+  const auto fnt = fontGetSystemFont();
+  const auto fnt_info = fontGetInfo(fnt);
+  const auto glyph_info = fontGetGlyphInfo(fnt);
+  // Resize the Texture list by the num of sysfont textures
+  ret->Textures.resize(glyph_info->nSheets + 1);
+  /// Modify the Pixel Height by 1.1f to fit the
+  /// Size og ttf font Rendering
+  ret->PixelHeight = glyph_info->cellHeight;
+  // Load the Textures and make sure they don't auto unload
+  for (size_t i = 0; i < glyph_info->nSheets; i++) {
+    auto stex = Li::Texture::New();
+    auto tx = new C3D_Tex;
+    tx->data = fontGetGlyphSheetTex(fnt, i);
+    tx->fmt = (GPU_TEXCOLOR)glyph_info->sheetFmt;
+    tx->size = glyph_info->sheetSize;
+    tx->width = glyph_info->sheetWidth;
+    tx->height = glyph_info->sheetHeight;
+    tx->param = GPU_TEXTURE_MAG_FILTER(GPU_LINEAR) |
+                GPU_TEXTURE_MIN_FILTER(GPU_LINEAR) |
+                GPU_TEXTURE_WRAP_S(GPU_REPEAT) | GPU_TEXTURE_WRAP_T(GPU_REPEAT);
+    tx->border = 0xffffffff;
+    tx->lodParam = 0;
+    stex->Address = (Li::TexAddress)tx;
+    stex->Size = fvec2(tx->width, tx->height);
+    stex->UV = fvec4(0, 1, 1, 0);
+    ret->Textures[i] = stex;
+  }
+  std::vector<unsigned int> charSet;
+  // Write the Charset into a vector
+  for (auto cmap = fnt_info->cmap; cmap; cmap = cmap->next) {
+    if (cmap->mappingMethod == CMAP_TYPE_DIRECT) {
+      if (cmap->codeEnd >= cmap->codeBegin) {
+        charSet.reserve(charSet.size() + cmap->codeEnd - cmap->codeBegin + 1);
+        for (auto i = cmap->codeBegin; i <= cmap->codeEnd; ++i) {
+          if (cmap->indexOffset + (i - cmap->codeBegin) == 0xFFFF) break;
+          charSet.emplace_back(i);
+        }
+      }
+    } else if (cmap->mappingMethod == CMAP_TYPE_TABLE) {
+      if (cmap->codeEnd >= cmap->codeBegin) {
+        charSet.reserve(charSet.size() + cmap->codeEnd - cmap->codeBegin + 1);
+        for (auto i = cmap->codeBegin; i <= cmap->codeEnd; ++i) {
+          if (cmap->indexTable[i - cmap->codeBegin] == 0xFFFF) continue;
+          charSet.emplace_back(i);
+        }
+      }
+    } else if (cmap->mappingMethod == CMAP_TYPE_SCAN) {
+      charSet.reserve(charSet.size() + cmap->nScanEntries);
+      for (unsigned i = 0; i < cmap->nScanEntries; ++i) {
+        if (cmap->scanEntries[i].code >= cmap->codeBegin &&
+            cmap->scanEntries[i].code <= cmap->codeEnd) {
+          if (cmap->scanEntries[i].glyphIndex != 0xFFFF) {
+            charSet.emplace_back(cmap->scanEntries[i].code);
+          }
+        }
+      }
+    } else {
+      continue;
+    }
+  }
+
+  // Sort the charset and make sure all values are unique
+  std::sort(charSet.begin(), charSet.end());
+  charSet.erase(std::unique(charSet.begin(), charSet.end()));
+
+  // Setup the Codepoint map by the charset
+  for (auto cp : charSet) {
+    int gidx = fontGlyphIndexFromCodePoint(fnt, cp);
+    if (gidx >= 0xFFFF) continue;
+    Li::Font::Codepoint codepoint;
+    fontGlyphPos_s dat;
+    fontCalcGlyphPos(&dat, fnt, gidx, GLYPH_POS_CALC_VTXCOORD, 1.f, 1.f);
+
+    codepoint.pCodepoint = cp;
+    codepoint.SimpleUV = fvec4(dat.texcoord.left, dat.texcoord.top,
+                               dat.texcoord.right, dat.texcoord.bottom);
+
+    if (dat.sheetIndex < (int)ret->Textures.size()) {
+      codepoint.Tex = ret->Textures[dat.sheetIndex];
+    } else {
+      codepoint.pInvalid = true;
+    }
+    codepoint.Size = fvec2(dat.vtxcoord.right, dat.vtxcoord.bottom);
+    codepoint.Offset = 0;
+    ret->CodeMap[cp] = codepoint;
+  }
+  return ret;
+}
+
 void Init(void* data) {
   // Dekstop Init Stage
   // First use default OS Driver