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mutter/src/compositor/meta-texture-tower.c

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/* -*- mode: C; c-file-style: "gnu"; indent-tabs-mode: nil; -*- */
/*
* MetaTextureTower
*
* Mipmap emulation by creation of scaled down images
*
* Copyright (C) 2009 Red Hat, Inc.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation; either version 2 of the
* License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
* 02111-1307, USA.
*/
#include <math.h>
#include <string.h>
#include "meta-texture-tower.h"
#include "meta-texture-rectangle.h"
#ifndef M_LOG2E
#define M_LOG2E 1.4426950408889634074
#endif
#define MAX_TEXTURE_LEVELS 12
/* If the texture format in memory doesn't match this, then Mesa
* will do the conversion, so things will still work, but it might
* be slow depending on how efficient Mesa is. These should be the
* native formats unless the display is 16bpp. If conversions
* here are a bottleneck, investigate whether we are converting when
* storing window data *into* the texture before adding extra code
* to handle multiple texture formats.
*/
#if G_BYTE_ORDER == G_LITTLE_ENDIAN
#define TEXTURE_FORMAT COGL_PIXEL_FORMAT_BGRA_8888_PRE
#else
#define TEXTURE_FORMAT COGL_PIXEL_FORMAT_ARGB_8888_PRE
#endif
typedef struct
{
guint16 x1;
guint16 y1;
guint16 x2;
guint16 y2;
} Box;
struct _MetaTextureTower
{
int n_levels;
CoglTexture *textures[MAX_TEXTURE_LEVELS];
CoglOffscreen *fbos[MAX_TEXTURE_LEVELS];
Box invalid[MAX_TEXTURE_LEVELS];
};
/**
* meta_texture_tower_new:
*
* Creates a new texture tower. The base texture has to be set with
* meta_texture_tower_set_base_texture() before use.
*
* Return value: the new texture tower. Free with meta_texture_tower_free()
*/
MetaTextureTower *
meta_texture_tower_new (void)
{
MetaTextureTower *tower;
tower = g_slice_new0 (MetaTextureTower);
return tower;
}
/**
* meta_texture_tower_free:
* @tower: a #MetaTextureTower
*
* Frees a texture tower created with meta_texture_tower_new().
*/
void
meta_texture_tower_free (MetaTextureTower *tower)
{
g_return_if_fail (tower != NULL);
meta_texture_tower_set_base_texture (tower, NULL);
g_slice_free (MetaTextureTower, tower);
}
/**
* meta_texture_tower_set_base_texture:
* @tower: a #MetaTextureTower
* @texture: the new texture used as a base for scaled down versions
*
* Sets the base texture that is the scaled texture that the
* scaled textures of the tower are derived from. The texture itself
* will be used as level 0 of the tower and will be referenced until
* unset or until the tower is freed.
*/
void
meta_texture_tower_set_base_texture (MetaTextureTower *tower,
CoglTexture *texture)
{
int i;
g_return_if_fail (tower != NULL);
if (texture == tower->textures[0])
return;
if (tower->textures[0] != NULL)
{
for (i = 1; i < tower->n_levels; i++)
{
if (tower->textures[i] != NULL)
{
cogl_object_unref (tower->textures[i]);
tower->textures[i] = NULL;
}
if (tower->fbos[i] != NULL)
{
cogl_object_unref (tower->fbos[i]);
tower->fbos[i] = NULL;
}
}
cogl_object_unref (tower->textures[0]);
}
tower->textures[0] = texture;
if (tower->textures[0] != NULL)
{
int width, height;
cogl_object_ref (tower->textures[0]);
width = cogl_texture_get_width (tower->textures[0]);
height = cogl_texture_get_height (tower->textures[0]);
tower->n_levels = 1 + MAX ((int)(M_LOG2E * log (width)), (int)(M_LOG2E * log (height)));
tower->n_levels = MIN(tower->n_levels, MAX_TEXTURE_LEVELS);
meta_texture_tower_update_area (tower, 0, 0, width, height);
}
else
{
tower->n_levels = 0;
}
}
/**
* meta_texture_tower_update_area:
* @tower: a #MetaTextureTower
* @x: X coordinate of upper left of rectangle that changed
* @y: Y coordinate of upper left of rectangle that changed
* @width: width of rectangle that changed
* @height: height rectangle that changed
*
* Mark a region of the base texture as having changed; the next
* time a scaled down version of the base texture is retrieved,
* the appropriate area of the scaled down texture will be updated.
*/
void
meta_texture_tower_update_area (MetaTextureTower *tower,
int x,
int y,
int width,
int height)
{
int texture_width, texture_height;
Box invalid;
int i;
g_return_if_fail (tower != NULL);
if (tower->textures[0] == NULL)
return;
texture_width = cogl_texture_get_width (tower->textures[0]);
texture_height = cogl_texture_get_height (tower->textures[0]);
invalid.x1 = x;
invalid.y1 = y;
invalid.x2 = x + width;
invalid.y2 = y + height;
for (i = 1; i < tower->n_levels; i++)
{
texture_width = MAX (1, texture_width / 2);
texture_height = MAX (1, texture_height / 2);
invalid.x1 = invalid.x1 / 2;
invalid.y1 = invalid.y1 / 2;
invalid.x2 = MIN (texture_width, (invalid.x2 + 1) / 2);
invalid.y2 = MIN (texture_height, (invalid.y2 + 1) / 2);
if (tower->invalid[i].x1 == tower->invalid[i].x2 ||
tower->invalid[i].y1 == tower->invalid[i].y2)
{
tower->invalid[i] = invalid;
}
else
{
tower->invalid[i].x1 = MIN (tower->invalid[i].x1, invalid.x1);
tower->invalid[i].y1 = MIN (tower->invalid[i].y1, invalid.y1);
tower->invalid[i].x2 = MAX (tower->invalid[i].x2, invalid.x2);
tower->invalid[i].y2 = MAX (tower->invalid[i].y2, invalid.y2);
}
}
}
/* It generally looks worse if we scale up a window texture by even a
* small amount than if we scale it down using bilinear filtering, so
* we always pick the *larger* adjacent level. */
#define LOD_BIAS (-0.49)
/* This determines the appropriate level of detail to use when drawing the
* texture, in a way that corresponds to what the GL specification does
* when mip-mapping. This is probably fancier and slower than what we need,
* but we do the computation only once each time we paint a window, and
* its easier to just use the equations from the specification than to
* come up with something simpler.
*
* If window is being painted at an angle from the viewer, then we have to
* pick a point in the texture; we use the middle of the texture (which is
* why the width/height are passed in.) This is not the normal case for
* Meta.
*/
static int
get_paint_level (int width, int height)
{
CoglMatrix projection, modelview, pm;
float v[4];
double viewport_width, viewport_height;
double u0, v0;
double xc, yc, wc;
double dxdu_, dxdv_, dydu_, dydv_;
double det_, det_sq;
double rho_sq;
double lambda;
/* See
* http://www.opengl.org/registry/doc/glspec32.core.20090803.pdf
* Section 3.8.9, p. 1.6.2. Here we have
*
* u(x,y) = x_o;
* v(x,y) = y_o;
*
* Since we are mapping 1:1 from object coordinates into pixel
* texture coordinates, the clip coordinates are:
*
* (x_c) (x_o) (u)
* (y_c) = (M_projection)(M_modelview) (y_o) = (PM) (v)
* (z_c) (z_o) (0)
* (w_c) (w_o) (1)
*/
cogl_get_projection_matrix (&projection);
cogl_get_modelview_matrix (&modelview);
cogl_matrix_multiply (&pm, &projection, &modelview);
cogl_get_viewport (v);
viewport_width = v[2];
viewport_height = v[3];
u0 = width / 2.;
v0 = height / 2.;
xc = pm.xx * u0 + pm.xy * v0 + pm.xw;
yc = pm.yx * u0 + pm.yy * v0 + pm.yw;
wc = pm.wx * u0 + pm.wy * v0 + pm.ww;
/* We'll simplify the equations below for a bit of micro-optimization.
* The commented out code is the unsimplified version.
// Partial derivates of window coordinates:
//
// x_w = 0.5 * viewport_width * x_c / w_c + viewport_center_x
// y_w = 0.5 * viewport_height * y_c / w_c + viewport_center_y
//
// with respect to u, v, using
// d(a/b)/dx = da/dx * (1/b) - a * db/dx / (b^2)
dxdu = 0.5 * viewport_width * (pm.xx - pm.wx * (xc/wc)) / wc;
dxdv = 0.5 * viewport_width * (pm.xy - pm.wy * (xc/wc)) / wc;
dydu = 0.5 * viewport_height * (pm.yx - pm.wx * (yc/wc)) / wc;
dydv = 0.5 * viewport_height * (pm.yy - pm.wy * (yc/wc)) / wc;
// Compute the inverse partials as the matrix inverse
det = dxdu * dydv - dxdv * dydu;
dudx = dydv / det;
dudy = - dxdv / det;
dvdx = - dydu / det;
dvdy = dvdu / det;
// Scale factor; maximum of the distance in texels for a change of 1 pixel
// in the X direction or 1 pixel in the Y direction
rho = MAX (sqrt (dudx * dudx + dvdx * dvdx), sqrt(dudy * dudy + dvdy * dvdy));
// Level of detail
lambda = log2 (rho) + LOD_BIAS;
*/
/* dxdu * wc, etc */
dxdu_ = 0.5 * viewport_width * (pm.xx - pm.wx * (xc/wc));
dxdv_ = 0.5 * viewport_width * (pm.xy - pm.wy * (xc/wc));
dydu_ = 0.5 * viewport_height * (pm.yx - pm.wx * (yc/wc));
dydv_ = 0.5 * viewport_height * (pm.yy - pm.wy * (yc/wc));
/* det * wc^2 */
det_ = dxdu_ * dydv_ - dxdv_ * dydu_;
det_sq = det_ * det_;
if (det_sq == 0.0)
return -1;
/* (rho * det * wc)^2 */
rho_sq = MAX (dydv_ * dydv_ + dydu_ * dydu_, dxdv_ * dxdv_ + dxdu_ * dxdu_);
lambda = 0.5 * M_LOG2E * log (rho_sq * wc * wc / det_sq) + LOD_BIAS;
#if 0
g_print ("%g %g %g\n", 0.5 * viewport_width * pm.xx / pm.ww, 0.5 * viewport_height * pm.yy / pm.ww, lambda);
#endif
if (lambda <= 0.)
return 0;
else
return (int)(0.5 + lambda);
}
static gboolean
is_power_of_two (int x)
{
return (x & (x - 1)) == 0;
}
static void
texture_tower_create_texture (MetaTextureTower *tower,
int level,
int width,
int height)
{
if ((!is_power_of_two (width) || !is_power_of_two (height)) &&
meta_texture_rectangle_check (tower->textures[level - 1]))
{
tower->textures[level] =
meta_texture_rectangle_new (width, height,
/* data format */
TEXTURE_FORMAT,
/* internal cogl format */
TEXTURE_FORMAT,
/* rowstride */
width * 4,
/* data */
NULL,
/* error */
NULL);
}
else
{
tower->textures[level] = cogl_texture_new_with_size (width, height,
COGL_TEXTURE_NO_AUTO_MIPMAP,
TEXTURE_FORMAT);
}
tower->invalid[level].x1 = 0;
tower->invalid[level].y1 = 0;
tower->invalid[level].x2 = width;
tower->invalid[level].y2 = height;
}
static gboolean
texture_tower_revalidate_fbo (MetaTextureTower *tower,
int level)
{
CoglTexture *source_texture = tower->textures[level - 1];
int source_texture_width = cogl_texture_get_width (source_texture);
int source_texture_height = cogl_texture_get_height (source_texture);
CoglTexture *dest_texture = tower->textures[level];
int dest_texture_width = cogl_texture_get_width (dest_texture);
int dest_texture_height = cogl_texture_get_height (dest_texture);
Box *invalid = &tower->invalid[level];
CoglMatrix modelview;
if (tower->fbos[level] == NULL)
tower->fbos[level] = cogl_offscreen_new_to_texture (dest_texture);
if (tower->fbos[level] == NULL)
return FALSE;
cogl_push_framebuffer (COGL_FRAMEBUFFER (tower->fbos[level]));
cogl_ortho (0, dest_texture_width, dest_texture_height, 0, -1., 1.);
cogl_matrix_init_identity (&modelview);
cogl_set_modelview_matrix (&modelview);
cogl_set_source_texture (tower->textures[level - 1]);
cogl_rectangle_with_texture_coords (invalid->x1, invalid->y1,
invalid->x2, invalid->y2,
(2. * invalid->x1) / source_texture_width,
(2. * invalid->y1) / source_texture_height,
(2. * invalid->x2) / source_texture_width,
(2. * invalid->y2) / source_texture_height);
cogl_pop_framebuffer ();
return TRUE;
}
static void
fill_copy (guchar *buf,
const guchar *source,
int width)
{
memcpy (buf, source, width * 4);
}
static void
fill_scale_down (guchar *buf,
const guchar *source,
int width)
{
while (width > 1)
{
buf[0] = (source[0] + source[4]) / 2;
buf[1] = (source[1] + source[5]) / 2;
buf[2] = (source[2] + source[6]) / 2;
buf[3] = (source[3] + source[7]) / 2;
buf += 4;
source += 8;
width -= 2;
}
if (width > 0)
{
buf[0] = source[0] / 2;
buf[1] = source[1] / 2;
buf[2] = source[2] / 2;
buf[3] = source[3] / 2;
}
}
static void
texture_tower_revalidate_client (MetaTextureTower *tower,
int level)
{
CoglTexture *source_texture = tower->textures[level - 1];
int source_texture_width = cogl_texture_get_width (source_texture);
int source_texture_height = cogl_texture_get_height (source_texture);
guint source_rowstride;
guchar *source_data;
CoglTexture *dest_texture = tower->textures[level];
int dest_texture_width = cogl_texture_get_width (dest_texture);
int dest_texture_height = cogl_texture_get_height (dest_texture);
int dest_x = tower->invalid[level].x1;
int dest_y = tower->invalid[level].y1;
int dest_width = tower->invalid[level].x2 - tower->invalid[level].x1;
int dest_height = tower->invalid[level].y2 - tower->invalid[level].y1;
guchar *dest_data;
guchar *source_tmp1 = NULL, *source_tmp2 = NULL;
int i, j;
source_rowstride = source_texture_width * 4;
source_data = g_malloc (source_texture_height * source_rowstride);
cogl_texture_get_data (source_texture, TEXTURE_FORMAT, source_rowstride,
source_data);
dest_data = g_malloc (dest_height * dest_width * 4);
if (dest_texture_height < source_texture_height)
{
source_tmp1 = g_malloc (dest_width * 4);
source_tmp2 = g_malloc (dest_width * 4);
}
for (i = 0; i < dest_height; i++)
{
guchar *dest_row = dest_data + i * dest_width * 4;
if (dest_texture_height < source_texture_height)
{
guchar *source1, *source2;
guchar *dest;
if (dest_texture_width < source_texture_width)
{
fill_scale_down (source_tmp1,
source_data + ((i + dest_y) * 2) * source_rowstride + dest_x * 2 * 4,
dest_width * 2);
fill_scale_down (source_tmp2,
source_data + ((i + dest_y) * 2 + 1) * source_rowstride + dest_x * 2 * 4,
dest_width * 2);
}
else
{
fill_copy (source_tmp1,
source_data + ((i + dest_y) * 2) * source_rowstride + dest_x * 4,
dest_width);
fill_copy (source_tmp2,
source_data + ((i + dest_y) * 2 + 1) * source_rowstride + dest_x * 4,
dest_width);
}
source1 = source_tmp1;
source2 = source_tmp2;
dest = dest_row;
for (j = 0; j < dest_width * 4; j++)
*(dest++) = (*(source1++) + *(source2++)) / 2;
}
else
{
if (dest_texture_width < source_texture_width)
fill_scale_down (dest_row,
source_data + (i + dest_y) * source_rowstride + dest_x * 2 * 4,
dest_width * 2);
else
fill_copy (dest_row,
source_data + (i + dest_y) * source_rowstride,
dest_width);
}
}
cogl_texture_set_region (dest_texture,
0, 0,
dest_x, dest_y,
dest_width, dest_height,
dest_width, dest_height,
TEXTURE_FORMAT,
4 * dest_width,
dest_data);
if (dest_texture_height < source_texture_height)
{
g_free (source_tmp1);
g_free (source_tmp2);
}
g_free (source_data);
g_free (dest_data);
}
static void
texture_tower_revalidate (MetaTextureTower *tower,
int level)
{
if (!texture_tower_revalidate_fbo (tower, level))
texture_tower_revalidate_client (tower, level);
}
/**
* meta_texture_tower_get_paint_texture:
* @tower: a #MetaTextureTower
*
* Gets the texture from the tower that best matches the current
* rendering scale. (On the assumption here the texture is going to
* be rendered with vertex coordinates that correspond to its
* size in pixels, so a 200x200 texture will be rendered on the
* rectangle (0, 0, 200, 200).
*
* Return value: the COGL texture handle to use for painting, or
* %NULL if no base texture has yet been set.
*/
CoglTexture *
meta_texture_tower_get_paint_texture (MetaTextureTower *tower)
{
int texture_width, texture_height;
int level;
g_return_val_if_fail (tower != NULL, NULL);
if (tower->textures[0] == NULL)
return NULL;
texture_width = cogl_texture_get_width (tower->textures[0]);
texture_height = cogl_texture_get_height (tower->textures[0]);
level = get_paint_level(texture_width, texture_height);
if (level < 0) /* singular paint matrix, scaled to nothing */
return NULL;
level = MIN (level, tower->n_levels - 1);
if (tower->textures[level] == NULL ||
(tower->invalid[level].x2 != tower->invalid[level].x1 &&
tower->invalid[level].y2 != tower->invalid[level].y1))
{
int i;
for (i = 1; i <= level; i++)
{
/* Use "floor" convention here to be consistent with the NPOT texture extension */
texture_width = MAX (1, texture_width / 2);
texture_height = MAX (1, texture_height / 2);
if (tower->textures[i] == NULL)
texture_tower_create_texture (tower, i, texture_width, texture_height);
}
for (i = 1; i <= level; i++)
{
if (tower->invalid[level].x2 != tower->invalid[level].x1 &&
tower->invalid[level].y2 != tower->invalid[level].y1)
texture_tower_revalidate (tower, i);
}
}
return tower->textures[level];
}
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