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text: gltex: fix rendering whithout GL_EXT_unpack_subimage

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OpenGLESv2 doesn't support specifying stride values for textures without
this extension. So allocate a temporary storage when uploading values
which have a default-stride.

This was reported by "towolf / Tobias Wolf" on github:
  https://github.com/dvdhrm/kmscon/issues/17

Signed-off-by: David Herrmann <dh.herrmann@googlemail.com>
This commit is contained in:
David Herrmann 2012-08-21 14:53:59 +02:00
parent 7ad970c1f4
commit 5f59c7953c
1 changed files with 70 additions and 11 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

81
src/text_gltex.c
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@ -88,6 +88,7 @@ struct glyph {
struct gltex {
struct kmscon_hashtable *glyphs;
unsigned int max_tex_size;
bool supports_rowlen;
struct kmscon_dlist atlases;
@ -144,6 +145,7 @@ static int gltex_set(struct kmscon_text *txt)
"fgcolor", "bgcolor" };
unsigned int sw, sh;
GLint s;
const char *ext;
memset(gt, 0, sizeof(*gt));
kmscon_dlist_init(&gt->atlases);
@ -192,6 +194,13 @@ static int gltex_set(struct kmscon_text *txt)
gl_clear_error();
ext = (const char*)glGetString(GL_EXTENSIONS);
if (ext && strstr((const char*)ext, "GL_EXT_unpack_subimage")) {
gt->supports_rowlen = true;
} else {
log_warning("your GL implementation does not support GL_EXT_unpack_subimage, glyph-rendering may be slower than usual");
}
return 0;
err_shader:
@ -363,8 +372,9 @@ static int find_glyph(struct kmscon_text *txt, struct glyph **out,
struct atlas *atlas;
struct glyph *glyph;
bool res;
int ret;
int ret, i;
GLenum err;
uint8_t *packed_data, *dst, *src;
res = kmscon_hashtable_find(gt->glyphs, (void**)&glyph,
(void*)(unsigned long)ch);
@ -394,25 +404,74 @@ static int find_glyph(struct kmscon_text *txt, struct glyph **out,
goto err_free;
}
/* Funnily, not all OpenGLESv2 implementations support specifying the
* stride of a texture. Therefore, we then need to create a
* temporary image with a stride equal to the image width for loading
* the texture. This may slow down loading new glyphs but doesn't affect
* overall rendering performance. But driver developers should really
* add this! */
gl_clear_error();
glBindTexture(GL_TEXTURE_2D, atlas->tex);
glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
glPixelStorei(GL_UNPACK_ROW_LENGTH, GLYPH_STRIDE(glyph));
glTexSubImage2D(GL_TEXTURE_2D, 0,
FONT_WIDTH(txt) * atlas->fill, 0,
GLYPH_WIDTH(glyph),
GLYPH_HEIGHT(glyph),
GL_ALPHA, GL_UNSIGNED_BYTE,
GLYPH_DATA(glyph));
glPixelStorei(GL_UNPACK_ROW_LENGTH, 0);
if (!gt->supports_rowlen) {
if (GLYPH_STRIDE(glyph) == GLYPH_WIDTH(glyph)) {
glTexSubImage2D(GL_TEXTURE_2D, 0,
FONT_WIDTH(txt) * atlas->fill, 0,
GLYPH_WIDTH(glyph),
GLYPH_HEIGHT(glyph),
GL_ALPHA, GL_UNSIGNED_BYTE,
GLYPH_DATA(glyph));
} else {
packed_data = malloc(GLYPH_WIDTH(glyph) * GLYPH_HEIGHT(glyph));
if (!packed_data) {
log_error("cannot allocate memory for glyph storage");
ret = -ENOMEM;
goto err_free;
}
src = GLYPH_DATA(glyph);
dst = packed_data;
for (i = 0; i < GLYPH_HEIGHT(glyph); ++i) {
memcpy(dst, src, GLYPH_WIDTH(glyph));
dst += GLYPH_WIDTH(glyph);
src += GLYPH_STRIDE(glyph);
}
glTexSubImage2D(GL_TEXTURE_2D, 0,
FONT_WIDTH(txt) * atlas->fill, 0,
GLYPH_WIDTH(glyph),
GLYPH_HEIGHT(glyph),
GL_ALPHA, GL_UNSIGNED_BYTE,
packed_data);
free(packed_data);
}
} else {
glPixelStorei(GL_UNPACK_ROW_LENGTH, GLYPH_STRIDE(glyph));
glTexSubImage2D(GL_TEXTURE_2D, 0,
FONT_WIDTH(txt) * atlas->fill, 0,
GLYPH_WIDTH(glyph),
GLYPH_HEIGHT(glyph),
GL_ALPHA, GL_UNSIGNED_BYTE,
GLYPH_DATA(glyph));
glPixelStorei(GL_UNPACK_ROW_LENGTH, 0);
}
glPixelStorei(GL_UNPACK_ALIGNMENT, 4);
/* Check for GL-errors
* As OpenGL is a state-machine, we cannot really tell which call failed
* without adding a glGetError() after each call. This is totally
* overkill so let us at least catch the error afterwards.
* We also add a hint to disable OpenGL if this does not work. This
* should _always_ work but OpenGL is kind of a black-box that isn't
* verbose at all and many things can go wrong. */
err = glGetError();
if (err != GL_NO_ERROR) {
gl_clear_error();
log_warning("cannot load glyph data into OpenGL texture (%d)",
err);
log_warning("cannot load glyph data into OpenGL texture (%d: %s); disable the GL-renderer if this does not work reliably",
err, gl_err_to_str(err));
ret = -EFAULT;
goto err_free;
}