diff --git a/src/openrct2/drawing/ttf_sdlport.c b/src/openrct2/drawing/TTFSDLPort.cpp
similarity index 98%
rename from src/openrct2/drawing/ttf_sdlport.c
rename to src/openrct2/drawing/TTFSDLPort.cpp
index ecf90de93d..2bdad7fea4 100644
--- a/src/openrct2/drawing/ttf_sdlport.c
+++ b/src/openrct2/drawing/TTFSDLPort.cpp
@@ -642,7 +642,7 @@ static FT_Error Load_Glyph(TTF_Font* font, uint16 ch, c_glyph* cached, int want)
     if (((want & CACHED_BITMAP) && !(cached->stored & CACHED_BITMAP)) ||
         ((want & CACHED_PIXMAP) && !(cached->stored & CACHED_PIXMAP))) {
         int mono = (want & CACHED_BITMAP);
-        int i;
+        unsigned int i;
         FT_Bitmap* src;
         FT_Bitmap* dst;
         FT_Glyph bitmap_glyph = NULL;
@@ -740,7 +740,7 @@ static FT_Error Load_Glyph(TTF_Font* font, uint16 ch, c_glyph* cached, int want)
                 if (mono) {
                     unsigned char *srcp = src->buffer + soffset;
                     unsigned char *dstp = dst->buffer + doffset;
-                    int j;
+                    unsigned int j;
                     if (src->pixel_mode == FT_PIXEL_MODE_MONO) {
                         for (j = 0; j < src->width; j += 8) {
                             unsigned char c = *srcp++;
@@ -801,7 +801,7 @@ static FT_Error Load_Glyph(TTF_Font* font, uint16 ch, c_glyph* cached, int want)
                     unsigned char *srcp = src->buffer + soffset;
                     unsigned char *dstp = dst->buffer + doffset;
                     unsigned char c;
-                    int j, k;
+                    unsigned int j, k;
                     for (j = 0; j < src->width; j += 8) {
                         c = *srcp++;
                         for (k = 0; k < 8; ++k) {
@@ -819,7 +819,7 @@ static FT_Error Load_Glyph(TTF_Font* font, uint16 ch, c_glyph* cached, int want)
                     unsigned char *srcp = src->buffer + soffset;
                     unsigned char *dstp = dst->buffer + doffset;
                     unsigned char c;
-                    int j, k;
+                    unsigned int j, k;
                     for (j = 0; j < src->width; j += 4) {
                         c = *srcp++;
                         for (k = 0; k < 4; ++k) {
@@ -837,7 +837,7 @@ static FT_Error Load_Glyph(TTF_Font* font, uint16 ch, c_glyph* cached, int want)
                     unsigned char *srcp = src->buffer + soffset;
                     unsigned char *dstp = dst->buffer + doffset;
                     unsigned char c;
-                    int j, k;
+                    unsigned int j, k;
                     for (j = 0; j < src->width; j += 2) {
                         c = *srcp++;
                         for (k = 0; k < 2; ++k) {
@@ -1172,7 +1172,7 @@ TTFSurface *TTF_RenderUTF8_Solid(TTF_Font *font,
     uint8* src;
     uint8* dst;
     uint8 *dst_check;
-    int row, col;
+    unsigned int row, col;
     c_glyph *glyph;
 
     FT_Bitmap *current;
@@ -1190,7 +1190,7 @@ TTFSurface *TTF_RenderUTF8_Solid(TTF_Font *font,
     }
 
     /* Create the target surface */
-    textbuf = calloc(1, sizeof(TTFSurface));
+    textbuf = (TTFSurface *)calloc(1, sizeof(TTFSurface));
     if (textbuf == NULL) {
         return NULL;
     }
@@ -1245,10 +1245,10 @@ TTFSurface *TTF_RenderUTF8_Solid(TTF_Font *font,
         for (row = 0; row < current->rows; ++row) {
             /* Make sure we don't go either over, or under the
             * limit */
-            if (row + glyph->yoffset < 0) {
+            if ((signed)row + glyph->yoffset < 0) {
                 continue;
             }
-            if (row + glyph->yoffset >= textbuf->h) {
+            if ((signed)row + glyph->yoffset >= textbuf->h) {
                 continue;
             }
             dst = (uint8*)textbuf->pixels +
@@ -1293,7 +1293,7 @@ TTFSurface *TTF_RenderUTF8_Shaded(TTF_Font *font,
     uint8* src;
     uint8* dst;
     uint8* dst_check;
-    int row, col;
+    unsigned int row, col;
     FT_Bitmap* current;
     c_glyph *glyph;
     FT_Error error;
@@ -1311,7 +1311,7 @@ TTFSurface *TTF_RenderUTF8_Shaded(TTF_Font *font,
     }
 
     /* Create the target surface */
-    textbuf = calloc(1, sizeof(TTFSurface));
+    textbuf = (TTFSurface *)calloc(1, sizeof(TTFSurface));
     if (textbuf == NULL)
     {
         return NULL;
@@ -1378,11 +1378,11 @@ TTFSurface *TTF_RenderUTF8_Shaded(TTF_Font *font,
         {
             /* Make sure we don't go either over, or under the
              * limit */
-            if (row + glyph->yoffset < 0)
+            if ((signed)row + glyph->yoffset < 0)
             {
                 continue;
             }
-            if (row + glyph->yoffset >= textbuf->h)
+            if ((signed)row + glyph->yoffset >= textbuf->h)
             {
                 continue;
             }