cogl-sub-texture: Optimise taking a sub texture of a sub texture
When creating a Cogl sub-texture, if the full texture is also a sub texture it will now just offset the x and y and reference the full texture instead. This avoids one level of indirection when rendering the texture which reduces the chances of getting rounding errors in the calculations.
This commit is contained in:
Neil Roberts
parent
2018b5b167
commit
4be4f56bdf
4 changed files with 99 additions and 40 deletions
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@ -35,9 +35,22 @@ struct _CoglSubTexture
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{
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CoglTexture _parent;
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/* This is the texture that was passed in to
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_cogl_sub_texture_new. If this is also a sub texture then we will
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use the full texture from that to render instead of making a
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chain. However we want to preserve the next texture in case the
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user is expecting us to keep a reference and also so that we can
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later add a cogl_sub_texture_get_full_texture() function. */
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CoglHandle next_texture;
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/* This is the texture that will actually be used to draw. It will
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point to the end of the chain if a sub texture of a sub texture
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is created */
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CoglHandle full_texture;
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/* The region represented by this sub-texture */
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/* The region represented by this sub-texture. This is the region of
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full_texture which won't necessarily be the same as the region
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passed to _cogl_sub_texture_new if next_texture is actually
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already a sub texture */
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int sub_x;
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int sub_y;
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int sub_width;
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@ -48,7 +61,7 @@ GQuark
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_cogl_handle_sub_texture_get_type (void);
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CoglHandle
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_cogl_sub_texture_new (CoglHandle full_texture,
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_cogl_sub_texture_new (CoglHandle next_texture,
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int sub_x,
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int sub_y,
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int sub_width,
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@ -235,34 +235,51 @@ _cogl_sub_texture_set_wrap_mode_parameter (CoglTexture *tex,
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static void
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_cogl_sub_texture_free (CoglSubTexture *sub_tex)
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{
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cogl_handle_unref (sub_tex->next_texture);
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cogl_handle_unref (sub_tex->full_texture);
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g_free (sub_tex);
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}
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CoglHandle
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_cogl_sub_texture_new (CoglHandle full_texture,
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_cogl_sub_texture_new (CoglHandle next_texture,
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int sub_x, int sub_y,
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int sub_width, int sub_height)
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{
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CoglHandle full_texture;
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CoglSubTexture *sub_tex;
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CoglTexture *tex;
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unsigned int full_width, full_height;
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unsigned int next_width, next_height;
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full_width = cogl_texture_get_width (full_texture);
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full_height = cogl_texture_get_height (full_texture);
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next_width = cogl_texture_get_width (next_texture);
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next_height = cogl_texture_get_height (next_texture);
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/* The region must specify a non-zero subset of the full texture */
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g_return_val_if_fail (sub_x >= 0 && sub_y >= 0, COGL_INVALID_HANDLE);
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g_return_val_if_fail (sub_width > 0 && sub_height > 0, COGL_INVALID_HANDLE);
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g_return_val_if_fail (sub_x + sub_width <= full_width, COGL_INVALID_HANDLE);
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g_return_val_if_fail (sub_y + sub_height <= full_height, COGL_INVALID_HANDLE);
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g_return_val_if_fail (sub_x + sub_width <= next_width, COGL_INVALID_HANDLE);
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g_return_val_if_fail (sub_y + sub_height <= next_height, COGL_INVALID_HANDLE);
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sub_tex = g_new (CoglSubTexture, 1);
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tex = COGL_TEXTURE (sub_tex);
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tex->vtable = &cogl_sub_texture_vtable;
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/* If the next texture is also a sub texture we can avoid one level
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of indirection by referencing the full texture of that texture
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instead. */
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if (cogl_is_sub_texture (next_texture))
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{
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CoglSubTexture *other_sub_tex =
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_cogl_sub_texture_pointer_from_handle (next_texture);
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full_texture = other_sub_tex->full_texture;
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sub_x += other_sub_tex->sub_x;
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sub_y += other_sub_tex->sub_y;
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}
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else
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full_texture = next_texture;
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sub_tex->next_texture = cogl_handle_ref (next_texture);
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sub_tex->full_texture = cogl_handle_ref (full_texture);
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sub_tex->sub_x = sub_x;
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@ -348,6 +348,10 @@ cogl_texture_set_region (CoglHandle handle,
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* of the range [0,1] are used. They also do not work with
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* CoglVertexBuffers.
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*
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* The sub texture will keep a reference to the full texture so you do
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* not need to keep one separately if you only want to use the sub
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* texture.
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*
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* Return value: a #CoglHandle to the new texture.
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*
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* Since: 1.2
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@ -67,10 +67,41 @@ create_source (void)
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data);
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}
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static CoglHandle
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create_test_texture (void)
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{
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CoglHandle tex;
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guint8 *data = g_malloc (256 * 256 * 4), *p = data;
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int x, y;
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/* Create a texture that is 256x256 where the red component ranges
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from 0->255 along the x axis and the green component ranges from
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0->255 along the y axis. The blue and alpha components are all
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255 */
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for (y = 0; y < 256; y++)
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for (x = 0; x < 256; x++)
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{
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*(p++) = x;
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*(p++) = y;
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*(p++) = 255;
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*(p++) = 255;
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}
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tex = cogl_texture_new_from_data (256, 256, COGL_TEXTURE_NONE,
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COGL_PIXEL_FORMAT_RGBA_8888_PRE,
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COGL_PIXEL_FORMAT_ANY,
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256 * 4,
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data);
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g_free (data);
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return tex;
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}
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static void
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draw_frame (TestState *state)
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{
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CoglHandle sub_texture;
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CoglHandle full_texture, sub_texture, sub_sub_texture;
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/* Create a sub texture of the bottom right quarter of the texture */
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sub_texture = cogl_texture_new_from_sub_texture (state->tex,
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@ -98,6 +129,19 @@ draw_frame (TestState *state)
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0.0f, 0.0f,
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2.0f, 1.0f);
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cogl_handle_unref (sub_texture);
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/* Create a sub texture of a sub texture */
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full_texture = create_test_texture ();
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sub_texture = cogl_texture_new_from_sub_texture (full_texture,
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20, 10, 30, 20);
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sub_sub_texture = cogl_texture_new_from_sub_texture (sub_texture,
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20, 10, 10, 10);
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cogl_set_source_texture (sub_sub_texture);
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cogl_rectangle (0.0f, SOURCE_SIZE * 2.0f,
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10.0f, SOURCE_SIZE * 2.0f + 10.0f);
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cogl_handle_unref (sub_sub_texture);
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cogl_handle_unref (sub_texture);
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cogl_handle_unref (full_texture);
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}
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static gboolean
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@ -131,37 +175,6 @@ validate_part (TestState *state,
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return pass;
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}
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static CoglHandle
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create_test_texture (void)
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{
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CoglHandle tex;
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guint8 *data = g_malloc (256 * 256 * 4), *p = data;
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int x, y;
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/* Create a texture that is 256x256 where the red component ranges
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from 0->255 along the x axis and the green component ranges from
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0->255 along the y axis. The blue and alpha components are all
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255 */
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for (y = 0; y < 256; y++)
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for (x = 0; x < 256; x++)
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{
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*(p++) = x;
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*(p++) = y;
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*(p++) = 255;
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*(p++) = 255;
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}
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tex = cogl_texture_new_from_data (256, 256, COGL_TEXTURE_NONE,
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COGL_PIXEL_FORMAT_RGBA_8888_PRE,
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COGL_PIXEL_FORMAT_ANY,
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256 * 4,
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data);
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g_free (data);
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return tex;
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}
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static guint8 *
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create_update_data (void)
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{
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@ -207,6 +220,18 @@ validate_result (TestState *state)
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DIVISION_WIDTH, DIVISION_HEIGHT,
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corner_colors + division_num));
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/* Sub sub texture */
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p = texture_data = clutter_stage_read_pixels (CLUTTER_STAGE (state->stage),
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0, SOURCE_SIZE * 2, 10, 10);
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for (y = 0; y < 10; y++)
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for (x = 0; x < 10; x++)
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{
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g_assert (*(p++) == x + 40);
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g_assert (*(p++) == y + 20);
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p += 2;
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}
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g_free (texture_data);
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/* Try reading back the texture data */
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sub_texture = cogl_texture_new_from_sub_texture (state->tex,
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SOURCE_SIZE / 4,
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