opengl: fix the renderer to draw glyphs at correct positions

1 files changed, 153 insertions, 81 deletions

diff --git a/src/sdl-freetype-opengl.c b/src/sdl-freetype-opengl.c
index b29e8a3..d7fefe6 100644
--- a/src/sdl-freetype-opengl.c
+++ b/src/sdl-freetype-opengl.c
@@ -37,14 +37,17 @@
 #include "sdl-freetype-opengl.h"
 #include "sdl-freetype-utils.h"
 
+#include  <assert.h>
 #include  <stdlib.h>
 #include  <stdio.h>
+
 #include  <GL/gl.h>
 
 #define FIXEDTOD(f) (sdl_freetype_fixed_to_double (f))
 
 #define GLYPH_CACHE_SIZE  512
 #define GLYPH_CACHE_LEVEL 64
+#define VERTEX_BUFFER_SIZE 128
 
 typedef struct sdl_freetype_opengl_render_s {
     sdl_freetype_glyph_render_t base;
@@ -56,6 +59,8 @@ typedef struct sdl_freetype_opengl_render_s {
     int width, height;
     float usx, usy;
     GLuint texture;
+    GLfloat vertex_buffer[VERTEX_BUFFER_SIZE * 6 * 2];
+    GLfloat texcoord_buffer[VERTEX_BUFFER_SIZE * 6 * 2];
 } sdl_freetype_opengl_render_t;
 
 typedef struct {
@@ -63,8 +68,10 @@ typedef struct {
 } sdl_freetype_opengl_coord_t;
 
 typedef struct {
+    sdl_freetype_font_t * font;
+    FT_UInt index;
     sdl_freetype_area_t * area;
-    sdl_freetype_bool_t locked;
+    int locked;
     sdl_freetype_opengl_coord_t uv[2];
 } sdl_freetype_opengl_user_data_t;
 
@@ -155,7 +162,7 @@ sdl_freetype_opengl_glyph_user_data_init (sdl_freetype_font_t * font,
         unsigned char * src, * dst;
         int h;
 
-        width = pitch = (bitmap->width + 3) & ~3;
+        width = pitch = (bitmap->width + 1 + 3) & ~3;
         data = calloc (pitch * info->bitmap.rows, 1);
         if (!data)
             return SDL_FREETYPE_ERR_OUT_OF_MEMORY;
@@ -175,7 +182,7 @@ sdl_freetype_opengl_glyph_user_data_init (sdl_freetype_font_t * font,
         unsigned char * src, * dst;
         int h;
 
-        width = pitch = (bitmap->width + 3) & ~3;
+        width = pitch = (bitmap->width + 1 + 3) & ~3;
         data = calloc (pitch * info->bitmap.rows, 1);
         if (!data)
             return SDL_FREETYPE_ERR_OUT_OF_MEMORY;
@@ -192,9 +199,9 @@ sdl_freetype_opengl_glyph_user_data_init (sdl_freetype_font_t * font,
     } else {
         data = NULL;
         pitch = bitmap->pitch;
-	width = (bitmap->width + 3) & ~3;
+	width = (bitmap->width + 1 + 3) & ~3;
     }
-    height = (bitmap->rows + 3) & ~3;
+    height = (bitmap->rows + 1 + 3) & ~3;
 
     user_data = sdl_freetype_opengl_user_data_create ();
     if (!user_data)
@@ -247,10 +254,12 @@ sdl_freetype_opengl_glyph_user_data_init (sdl_freetype_font_t * font,
     if (data)
         free (data);
 
-    user_data->uv[0].x = (float)area->x;
-    user_data->uv[0].y = (float)area->y;
-    user_data->uv[1].x = (float)(area->x + bitmap->width);
-    user_data->uv[1].y = (float)(area->y + bitmap->rows);
+    user_data->font = font;
+    user_data->index = index;
+    user_data->uv[0].x = (float)area->x / opengl_render->width;
+    user_data->uv[0].y = (float)area->y / opengl_render->height;
+    user_data->uv[1].x = (float)(area->x + bitmap->width) / opengl_render->width;
+    user_data->uv[1].y = (float)(area->y + bitmap->rows) / opengl_render->height;
     info->data = user_data;
     return SDL_FREETYPE_ERR_OK;
 }
@@ -292,7 +301,9 @@ sdl_freetype_opengl_glyphs_render (sdl_freetype_font_t * font,
     sdl_freetype_opengl_glyph_info_t * cached, stack_cached[LOCAL_BUF];
     sdl_freetype_glyph_info_t * info;
     double x1, y1, x2, y2;
-    int i, num_cached;
+    int i, start, num_cached;
+    sdl_freetype_bool_t dirty = SDL_FREETYPE_FALSE;
+    GLboolean blend_enabled;
 
     if (!render->valid) {
         for (i = 0; i < num_glyphs && !render->valid; i++)
@@ -304,12 +315,6 @@ sdl_freetype_opengl_glyphs_render (sdl_freetype_font_t * font,
             return SDL_FREETYPE_ERR_UNKNOWN;
     }
 
-    /* FIXME: only use alpha channel for supixel rendering */
-#if 0
-    if (render->subpixel)
-        return SDL_FREETYPE_ERR_NOT_IMPLEMENTED;
-#endif
-
     if (!render->width || !render->height)
         return SDL_FREETYPE_ERR_OK;
 
@@ -320,82 +325,148 @@ sdl_freetype_opengl_glyphs_render (sdl_freetype_font_t * font,
     if (!cached)
         return SDL_FREETYPE_ERR_OUT_OF_MEMORY;
 
-    glPushAttrib (GL_CURRENT_BIT | GL_ENABLE_BIT | GL_TRANSFORM_BIT);
-
-    num_cached = 0;
-    for (i = 0; i < num_glyphs; i++) {
-        info = sdl_freetype_font_glyph_info_lookup (font, glyphs[i].index,
-                                                    SDL_FREETYPE_GLYPH_SURFACE |
-                                                    SDL_FREETYPE_GLYPH_USER_DATA);
-        if (!info)
-            continue;
-        user_data = info->data;
-        if (!user_data || !user_data->area)
-            continue;
-        user_data->locked = SDL_FREETYPE_TRUE;
-        cached[num_cached].index  = i;
-        cached[num_cached++].info = info;
-    }
-
-    if (num_cached) {
-        glMatrixMode (GL_TEXTURE);
-        glPushMatrix ();
-        glLoadIdentity ();
-        glScalef (1.0f / render->width, 1.0f / render->height, 1.0f);
-
-        glMatrixMode (GL_MODELVIEW);
-        glPushMatrix ();
-
-        glEnable (GL_BLEND);
-        glBlendFunc (GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
-
-        glEnable (GL_TEXTURE_2D);
-        glBindTexture (GL_TEXTURE_2D, render->texture);
+    blend_enabled = glIsEnabled(GL_BLEND);
 
-        glTranslatef (x * render->usx, y * render->usy, 0.0f);
+    start = 0;
+    while (start < num_glyphs) {
+	int end;
 
-        glColor4ub (r, g, b, a);
+	num_cached = 0;
+	for (i = start; i < num_glyphs; i++) {
+	    info = sdl_freetype_font_glyph_info_lookup (font, glyphs[i].index,
+							SDL_FREETYPE_GLYPH_SURFACE |
+							SDL_FREETYPE_GLYPH_USER_DATA);
+	    if (!info || info->flags & SDL_FREETYPE_GLYPH_EMPTY)
+		continue;
+
+	    user_data = info->data;
+	    if (!user_data) {
+		if (num_cached)
+		    i--;
+		break;
+	    }
+	    if (!user_data->area)
+		continue;
+	    user_data->locked++;
+	    cached[num_cached].index  = i;
+	    cached[num_cached++].info = info;
+	}
+	end = i + 1;
+
+	if (num_cached) {
+	    GLfloat *vertex_buffer = render->vertex_buffer;
+	    GLfloat *texcoord_buffer = render->texcoord_buffer;
+	    int left = num_cached;
+
+	    if (!dirty) {
+		dirty = SDL_FREETYPE_TRUE;
+
+		glMatrixMode (GL_TEXTURE);
+		glPushMatrix ();
+		glLoadIdentity ();
+
+		glMatrixMode (GL_MODELVIEW);
+		glPushMatrix ();
+
+		glEnable (GL_BLEND);
+		glBlendFunc (GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
+
+		glEnable (GL_TEXTURE_2D);
+		glBindTexture (GL_TEXTURE_2D, render->texture);
+
+		glTranslatef (x * render->usx, y * render->usy, 0.0f);
+
+		glColor4ub (r, g, b, a);
+
+		glEnableClientState (GL_VERTEX_ARRAY);
+		glEnableClientState (GL_TEXTURE_COORD_ARRAY);
+
+		glVertexPointer (2, GL_FLOAT, 0, vertex_buffer);
+		glTexCoordPointer (2, GL_FLOAT, 0, texcoord_buffer);
+	    }
+
+	    i = 0;
+	    while (left) {
+		int num_quads = VERTEX_BUFFER_SIZE;
+		int max_index;
+		int j;
+
+		if (left < num_quads)
+		    num_quads = left;
+
+		max_index = i + num_quads;
+
+		for (j = 0; i < max_index; i++, j += 12) {
+		    user_data = cached[i].info->data;
+
+		    assert (user_data->locked != 0);
+
+		    x1 = FIXEDTOD (glyphs[cached[i].index].x) + cached[i].info->x_offset;
+		    y1 = FIXEDTOD (glyphs[cached[i].index].y) + cached[i].info->y_offset;
+		    x2 = x1 + cached[i].info->bitmap.width;
+		    y2 = y1 + cached[i].info->bitmap.rows;
+
+		    x1 *= render->usx;
+		    y1 *= render->usy;
+		    x2 *= render->usx;
+		    y2 *= render->usy;
+
+		    texcoord_buffer[j + 0] = user_data->uv[0].x;
+		    texcoord_buffer[j + 1] = user_data->uv[0].y;
+		    vertex_buffer[j + 0] = x1;
+		    vertex_buffer[j + 1] = y1;
+
+		    texcoord_buffer[j + 2] = user_data->uv[0].x;
+		    texcoord_buffer[j + 3] = user_data->uv[1].y;
+		    vertex_buffer[j + 2] = x1;
+		    vertex_buffer[j + 3] = y2;
+
+		    texcoord_buffer[j + 4] = user_data->uv[1].x;
+		    texcoord_buffer[j + 5] = user_data->uv[1].y;
+		    vertex_buffer[j + 4] = x2;
+		    vertex_buffer[j + 5] = y2;
+
+		    texcoord_buffer[j + 6] = user_data->uv[1].x;
+		    texcoord_buffer[j + 7] = user_data->uv[1].y;
+		    vertex_buffer[j + 6] = x2;
+		    vertex_buffer[j + 7] = y2;
+
+		    texcoord_buffer[j + 8] = user_data->uv[1].x;
+		    texcoord_buffer[j + 9] = user_data->uv[0].y;
+		    vertex_buffer[j + 8] = x2;
+		    vertex_buffer[j + 9] = y1;
+
+		    texcoord_buffer[j + 10] = user_data->uv[0].x;
+		    texcoord_buffer[j + 11] = user_data->uv[0].y;
+		    vertex_buffer[j + 10] = x1;
+		    vertex_buffer[j + 11] = y1;
+
+		    user_data->locked--;
+		}
 
-        glBegin (GL_QUADS);
+		glDrawArrays (GL_TRIANGLES, 0, num_quads * 6);
 
-        for (i = 0; i < num_cached; i++) {
-            user_data = cached[i].info->data;
-
-            x1 = FIXEDTOD (glyphs[cached[i].index].x) + cached[i].info->x_offset;
-            y2 = -FIXEDTOD (glyphs[cached[i].index].y) - cached[i].info->y_offset;
-            x2 = x1 + cached[i].info->bitmap.width;
-            y1 = y2 - cached[i].info->bitmap.rows;
-
-            x1 *= render->usx;
-            y1 *= render->usy;
-            x2 *= render->usx;
-            y2 *= render->usy;
-
-            glTexCoord2f (user_data->uv[0].x, user_data->uv[1].y);
-            glVertex2f (x1, y1);
-
-            glTexCoord2f (user_data->uv[0].x, user_data->uv[0].y);
-            glVertex2f (x1, y2);
-
-            glTexCoord2f (user_data->uv[1].x, user_data->uv[0].y);
-            glVertex2f (x2, y2);
+		left -= num_quads;
+	    }
+	}
+	start = end;
+    }
 
-            glTexCoord2f (user_data->uv[1].x, user_data->uv[1].y);
-            glVertex2f (x2, y1);
+    if (dirty) {
+	glDisableClientState (GL_VERTEX_ARRAY);
+	glDisableClientState (GL_TEXTURE_COORD_ARRAY);
 
-            user_data->locked = SDL_FREETYPE_FALSE;
-        }
+	glPopMatrix ();
 
-        glEnd ();
+	glMatrixMode (GL_TEXTURE);
+	glPopMatrix ();
 
-        glPopMatrix ();
+	if (!blend_enabled)
+	    glDisable (GL_BLEND);
 
-        glMatrixMode (GL_TEXTURE);
-        glPopMatrix ();
+	glBindTexture (GL_TEXTURE_2D, 0);
     }
 
-    glPopAttrib ();
-
     if (cached != stack_cached)
         free (cached);
 
@@ -438,6 +509,7 @@ sdl_freetype_opengl_glyph_move_out (sdl_freetype_area_manager_t * manager,
     sdl_freetype_opengl_user_data_t * user_data = closure;
 
     user_data->area = NULL;
+    sdl_freetype_font_glyph_clear_user_data(user_data->font, user_data->index);
 }
 
 static int