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/*
* Copyright 2012 Google, Inc. All Rights Reserved.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
* Google Author(s): Behdad Esfahbod
*/
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#include "demo-atlas.h"
struct demo_atlas_t {
unsigned int refcount;
GLuint tex_unit;
GLuint tex_name;
GLuint tex_w;
GLuint tex_h;
GLuint item_w;
GLuint item_h_q; /* height quantum */
GLuint cursor_x;
GLuint cursor_y;
};
demo_atlas_t *
demo_atlas_create (unsigned int w,
unsigned int h,
unsigned int item_w,
unsigned int item_h_quantum)
{
TRACE();
demo_atlas_t *at = static_cast<demo_atlas_t *>(calloc (1, sizeof (demo_atlas_t)));
at->refcount = 1;
glGetIntegerv (GL_ACTIVE_TEXTURE, reinterpret_cast<GLint *>(&at->tex_unit));
glGenTextures (1, &at->tex_name);
at->tex_w = w;
at->tex_h = h;
at->item_w = item_w;
at->item_h_q = item_h_quantum;
at->cursor_x = 0;
at->cursor_y = 0;
demo_atlas_bind_texture (at);
glTexParameterf (GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
glTexParameterf (GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
gl(TexImage2D) (GL_TEXTURE_2D, 0, GL_RGBA, at->tex_w, at->tex_h, 0, GL_RGBA, GL_UNSIGNED_BYTE, nullptr);
return at;
}
demo_atlas_t *
demo_atlas_reference (demo_atlas_t *at)
{
if (at) at->refcount++;
return at;
}
void
demo_atlas_destroy (demo_atlas_t *at)
{
if (!at || --at->refcount)
return;
glDeleteTextures (1, &at->tex_name);
free (at);
}
void
demo_atlas_bind_texture (demo_atlas_t *at)
{
glActiveTexture (at->tex_unit);
glBindTexture (GL_TEXTURE_2D, at->tex_name);
}
void
demo_atlas_set_uniforms (demo_atlas_t *at)
{
GLuint program;
glGetIntegerv (GL_CURRENT_PROGRAM, reinterpret_cast<GLint *>(&program));
glUniform4i (glGetUniformLocation (program, "u_atlas_info"),
at->tex_w, at->tex_h, at->item_w, at->item_h_q);
glUniform1i (glGetUniformLocation (program, "u_atlas_tex"), at->tex_unit - GL_TEXTURE0);
}
void
demo_atlas_alloc (demo_atlas_t *at,
glyphy_rgba_t *data,
unsigned int len,
unsigned int *px,
unsigned int *py)
{
GLuint w, h, x = 0, y = 0;
w = at->item_w;
h = (len + w - 1) / w;
if (at->cursor_y + h > at->tex_h) {
/* Go to next column */
at->cursor_x += at->item_w;
at->cursor_y = 0;
}
if (at->cursor_x + w <= at->tex_w &&
at->cursor_y + h <= at->tex_h)
{
x = at->cursor_x;
y = at->cursor_y;
at->cursor_y += (h + at->item_h_q - 1) & ~(at->item_h_q - 1);
} else
die ("Ran out of atlas memory");
demo_atlas_bind_texture (at);
if (w * h == len)
gl(TexSubImage2D) (GL_TEXTURE_2D, 0, x, y, w, h, GL_RGBA, GL_UNSIGNED_BYTE, data);
else {
gl(TexSubImage2D) (GL_TEXTURE_2D, 0, x, y, w, h - 1, GL_RGBA, GL_UNSIGNED_BYTE, data);
/* Upload the last row separately */
gl(TexSubImage2D) (GL_TEXTURE_2D, 0, x, y + h - 1, len - (w * (h - 1)), 1, GL_RGBA, GL_UNSIGNED_BYTE,
data + w * (h - 1));
}
*px = x / at->item_w;
*py = y / at->item_h_q;
}
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