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mutter/src/compositor/meta-texture-tower.c
Neil Roberts fccd626604 Use a utility function to create GL_ARB_texture_rectangles 
meta-texture-rectangle and meta-shaped-texture both create textures
with GL_TEXTURE_RECTANGLE_ARB as the target using direct GL
calls. This patch moves that code into a shared utility function in a
separate file instead. The function resolves the required GL symbols
dynamically instead of linking to them directly so that if Clutter
eventually stops linking to -lGL mutter will continue to build. The
function also splits the texture creation into a separate texture
creation and data upload stage so that it can use
cogl_texture_set_region to upload the data. That way it can avoid
clobbering the glPixelStore state and it can let Cogl do any necessary
format conversion. The code preserves the old value of the rectangle
texture binding instead of clobbering it because Cogl expects to be
able to cache this value to avoid redundant glBindTexture
calls. Finally, the function uses cogl_object_set_data to
automatically destroy the GL texture when the Cogl texture is
destroyed. This avoids having to have special code to destroy the cogl
texture.

https://bugzilla.gnome.org/show_bug.cgi?id=654569
2011-07-19 11:06:23 +01:00

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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;
CoglHandle textures[MAX_TEXTURE_LEVELS];
CoglHandle 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, COGL_INVALID_HANDLE);
g_slice_free (MetaTextureTower, tower);
}
#ifdef GL_TEXTURE_RECTANGLE_ARB
static gboolean
texture_is_rectangle (CoglHandle texture)
{
GLuint gl_tex;
GLenum gl_target;
cogl_texture_get_gl_texture (texture, &gl_tex, &gl_target);
return gl_target == GL_TEXTURE_RECTANGLE_ARB;
}
#endif /* GL_TEXTURE_RECTANGLE_ARB */
/**
* meta_texture_tower_update_area:
* @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,
CoglHandle texture)
{
int i;
g_return_if_fail (tower != NULL);
if (texture == tower->textures[0])
return;
if (tower->textures[0] != COGL_INVALID_HANDLE)
{
for (i = 1; i < tower->n_levels; i++)
{
if (tower->textures[i] != COGL_INVALID_HANDLE)
{
cogl_handle_unref (tower->textures[i]);
tower->textures[i] = COGL_INVALID_HANDLE;
}
if (tower->fbos[i] != COGL_INVALID_HANDLE)
{
cogl_handle_unref (tower->fbos[i]);
tower->fbos[i] = COGL_INVALID_HANDLE;
}
}
cogl_handle_unref (tower->textures[0]);
}
tower->textures[0] = texture;
if (tower->textures[0] != COGL_INVALID_HANDLE)
{
int width, height;
cogl_handle_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);
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);
}
#ifdef GL_TEXTURE_RECTANGLE_ARB
static gboolean
is_power_of_two (int x)
{
return (x & (x - 1)) == 0;
}
#endif /* GL_TEXTURE_RECTANGLE_ARB */
static void
texture_tower_create_texture (MetaTextureTower *tower,
int level,
int width,
int height)
{
#ifdef GL_TEXTURE_RECTANGLE_ARB
if ((!is_power_of_two (width) || !is_power_of_two (height)) &&
texture_is_rectangle (tower->textures[level - 1]))
{
tower->textures[level] =
meta_texture_rectangle_new (width, height,
0, /* flags */
/* data format */
TEXTURE_FORMAT,
/* internal GL format */
GL_RGBA,
/* internal cogl format */
TEXTURE_FORMAT,
/* rowstride */
width * 4,
NULL);
}
else
#endif /* GL_TEXTURE_RECTANGLE_ARB */
{
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)
{
CoglHandle 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);
CoglHandle 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] == COGL_INVALID_HANDLE)
tower->fbos[level] = cogl_offscreen_new_to_texture (dest_texture);
if (tower->fbos[level] == COGL_INVALID_HANDLE)
return FALSE;
cogl_push_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)
{
CoglHandle 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;
CoglHandle 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_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
* %COGL_INVALID_HANDLE if no base texture has yet been set.
*/
CoglHandle
meta_texture_tower_get_paint_texture (MetaTextureTower *tower)
{
int texture_width, texture_height;
int level;
g_return_val_if_fail (tower != NULL, COGL_INVALID_HANDLE);
if (tower->textures[0] == COGL_INVALID_HANDLE)
return COGL_INVALID_HANDLE;
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 COGL_INVALID_HANDLE;
level = MIN (level, tower->n_levels - 1);
if (tower->textures[level] == COGL_INVALID_HANDLE ||
(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] == COGL_INVALID_HANDLE)
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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