more text rendering

1 files changed, 65 insertions, 17 deletions

diff --git a/text.c b/text.c
index 19d62a2..7007ad6 100644
--- a/text.c
+++ b/text.c
@@ -1,27 +1,25 @@
 #include "base.h"
+#include "text.h"
+#define STB_TRUETYPE_IMPLEMENTATION
+#define STBTT_STATIC
 no_warn_start
 #include "stb_truetype.h"
 no_warn_end
 #include <stdarg.h>
 #include <stdlib.h>
+#include <GL/gl.h>
 
-typedef struct {
+struct Font {
 	float char_height;
-	u32 nchars;
 	GLuint texture;
+	u32 nchars;
 	stbtt_bakedchar chars[];
-} Font;
+};
 
 static char text_err[200];
 static void text_clear_err(void) {
 	text_err[0] = '\0';
 }
-static void text_set_err(char const *fmt, ...) {
-	va_list args;
-	va_start(args, fmt);
-	vsnprintf(text_err, sizeof text_err - 1, fmt, args);
-	va_end(args);
-}
 
 static bool text_has_err(void) {
 	return text_err[0] != '\0';
@@ -31,6 +29,15 @@ char const *text_get_err(void) {
 	return text_err;
 }
 
+static void text_set_err(char const *fmt, ...) {
+	if (!text_has_err()) {
+		va_list args;
+		va_start(args, fmt);
+		vsnprintf(text_err, sizeof text_err - 1, fmt, args);
+		va_end(args);
+	}
+}
+
 Font *text_font_load(char const *ttf_filename, float font_size) {
 	Font *font = NULL;
 	u32 nchars = 128;
@@ -42,30 +49,71 @@ Font *text_font_load(char const *ttf_filename, float font_size) {
 		fseek(ttf_file, 0, SEEK_END);
 		u32 file_size = (u32)ftell(ttf_file);
 		if (file_size < (50UL<<20)) { // fonts aren't usually bigger than 50 MB
-			char *file_data = calloc(1, file_size);
-			Font *font = calloc(1, sizeof *font + nchars * sizeof *font->chars);
+			u8 *file_data = calloc(1, file_size);
+			font = calloc(1, sizeof *font + nchars * sizeof *font->chars);
 			if (file_data && font) {
-				font->nchars = nchars;
-				font->char_height = font_size;
-				stbtt_
+				if (fread(file_data, 1, file_size, ttf_file) == file_size) {
+					font->nchars = nchars;
+					font->char_height = font_size;
+
+					for (int bitmap_width = 256, bitmap_height = 256; bitmap_width <= 4096; bitmap_width *= 2, bitmap_height *= 2) {
+						u8 *bitmap = calloc((size_t)bitmap_width, (size_t)bitmap_height);
+						if (bitmap) {
+							int err = stbtt_BakeFontBitmap(file_data, 0, font->char_height, bitmap,
+								bitmap_width, bitmap_height, 0, (int)font->nchars, font->chars);
+							if (err > 0) {
+								// font converted to bitmap successfully.
+								GLuint texture = 0;
+								glGenTextures(1, &texture);
+								glBindTexture(GL_TEXTURE_2D, texture);
+								glTexImage2D(GL_TEXTURE_2D, 0, GL_ALPHA, bitmap_width, bitmap_height, 0, GL_ALPHA, GL_UNSIGNED_BYTE, bitmap);
+								glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
+								glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
+							#if DEBUG
+								debug_println("Loaded font %s with %dx%d bitmap.", ttf_filename, bitmap_width, bitmap_height);
+							#endif
+								font->texture = texture;
+								if (glGetError()) {
+									text_set_err("Couldn't create texture for font.");
+								}
+							}
+						} else {
+							text_set_err("Not enough memory for font bitmap.");
+						}
+						free(bitmap);
+						if (font->texture) { // if font loaded successfully
+							break;
+						}
+					}
+					if (!font->texture && !text_has_err()) {
+						text_set_err("Couldn't convert font to bitmap.");
+					}
+				} else {
+					text_set_err("Couldn't read font file.", ttf_filename);
+				}
 			} else {
 				text_set_err("Not enough memory for font.");
 			}
 			free(file_data);
-			if (text_has_err())
+			if (text_has_err()) {
 				free(font);
+				font = NULL;
+			}
 			fclose(ttf_file);
 		} else {
 			text_set_err("Font file too big (%u megabytes).", (uint)(file_size >> 20));
 		}
 	} else {
-		text_set_err("Couldn't open font file: %s.", ttf_filename);
+		text_set_err("Couldn't open font file.", ttf_filename);
 	}
-	return NULL;
+	return font;
 }
 
+#if 0
 void text_render(Font *font, char const *text, float x, float y) {
+	
 }
 
 void text_get_size(Font *font, char const *text, float *width, float *height) {
 }
+#endif