fdo-mirrors/cairo
1
0
Fork 0
mirror of https://gitlab.freedesktop.org/cairo/cairo.git synced 2026-05-05 18:08:03 +02:00
Code Issues Projects Releases Packages Wiki Activity Actions

[gl] Use GL_RGBA textures even for CAIRO_CONTENT_COLOR.

Browse source 
When the texture is GL_RGB, GL_CLAMP_TO_BORDER (EXTEND_NONE) fills the
border color alpha channel with 1, when the whole reason we were using
the border color was to get a color and alpha of 0.  We're forced to
use GL_RGBA textures and do extra work to fill in the alpha channel of
them to 1 to get cairo's desired behavior.

This fixes a failure in rotate-image-surface-paint and 4 other
testcases.  No performance difference in firefox-talos-gfx.
This commit is contained in:
Eric Anholt 2010-01-21 13:19:17 -08:00
parent e316cb9db5
commit 12d521df8a
1 changed files with 75 additions and 56 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

131
src/cairo-gl-surface.c
View file

@ -42,6 +42,13 @@
slim_hidden_proto (cairo_gl_context_reference);
slim_hidden_proto (cairo_gl_context_destroy);
static cairo_int_status_t
_cairo_gl_surface_fill_rectangles (void *abstract_surface,
cairo_operator_t op,
const cairo_color_t *color,
cairo_rectangle_int_t *rects,
int num_rects);
#define BIAS .375
static inline float
@ -379,8 +386,9 @@ _cairo_gl_set_operator (cairo_gl_surface_t *dst, cairo_operator_t op,
src_factor = blend_factors[op].src;
dst_factor = blend_factors[op].dst;
/* We may have a visual with alpha bits despite the user requesting
* CAIRO_CONTENT_COLOR. So clear out those bits in that case.
/* Even when the user requests CAIRO_CONTENT_COLOR, we use GL_RGBA
* due to texture filtering of GL_CLAMP_TO_BORDER. So fix those
* bits in that case.
*/
if (dst->base.content == CAIRO_CONTENT_COLOR) {
if (src_factor == GL_ONE_MINUS_DST_ALPHA)
@ -486,10 +494,19 @@ _cairo_gl_surface_create_scratch (cairo_gl_context_t *ctx,
format = GL_RGBA;
break;
case CAIRO_CONTENT_ALPHA:
/* We want to be trying GL_ALPHA framebuffer objects here. */
format = GL_RGBA;
break;
case CAIRO_CONTENT_COLOR:
format = GL_RGB;
/* GL_RGB is almost what we want here -- sampling 1 alpha when
* texturing, using 1 as destination alpha factor in blending,
* etc. However, when filtering with GL_CLAMP_TO_BORDER, the
* alpha channel of the border color will also be clamped to
* 1, when we actually want the border color we explicitly
* specified. So, we have to store RGBA, and fill the alpha
* channel with 1 when blending.
*/
format = GL_RGBA;
break;
}
@ -524,6 +541,24 @@ _cairo_gl_surface_create_scratch (cairo_gl_context_t *ctx,
return &surface->base;
}
static void
_cairo_gl_surface_clear (cairo_gl_surface_t *surface)
{
cairo_gl_context_t *ctx;
ctx = _cairo_gl_context_acquire (surface->ctx);
_cairo_gl_set_destination (surface);
if (surface->base.content == CAIRO_CONTENT_COLOR)
glClearColor (0.0, 0.0, 0.0, 1.0);
else
glClearColor (0.0, 0.0, 0.0, 0.0);
glClear (GL_COLOR_BUFFER_BIT);
_cairo_gl_context_release (ctx);
surface->base.is_clear = TRUE;
}
cairo_surface_t *
cairo_gl_surface_create (cairo_gl_context_t *ctx,
cairo_content_t content,
@ -546,13 +581,7 @@ cairo_gl_surface_create (cairo_gl_context_t *ctx,
return &surface->base;
/* Cairo surfaces start out initialized to transparent (black) */
ctx = _cairo_gl_context_acquire (surface->ctx);
_cairo_gl_set_destination (surface);
glClearColor (0.0, 0.0, 0.0, 0.0);
glClear (GL_COLOR_BUFFER_BIT);
_cairo_gl_context_release (ctx);
surface->base.is_clear = TRUE;
_cairo_gl_surface_clear (surface);
return &surface->base;
}
@ -689,6 +718,32 @@ _cairo_gl_surface_draw_image (cairo_gl_surface_t *dst,
cairo_surface_destroy (&clone->base);
/* If we just treated some rgb-only data as rgba, then we have to
* go back and fix up the alpha channel where we filled in this
* texture data.
*/
if (!has_alpha) {
cairo_rectangle_int_t rect;
cairo_color_t color;
rect.x = dst_x;
rect.y = dst_y;
rect.width = width;
rect.height = height;
color.red = 0.0;
color.green = 0.0;
color.blue = 0.0;
color.alpha = 1.0;
glColorMask(GL_FALSE, GL_FALSE, GL_FALSE, GL_TRUE);
_cairo_gl_surface_fill_rectangles (dst,
CAIRO_OPERATOR_SOURCE,
&color,
&rect, 1);
glColorMask(GL_TRUE, GL_TRUE, GL_TRUE, GL_TRUE);
}
return CAIRO_STATUS_SUCCESS;
}
@ -1122,7 +1177,7 @@ _cairo_gl_set_src_operand (cairo_gl_context_t *ctx,
cairo_gl_composite_setup_t *setup)
{
cairo_surface_attributes_t *src_attributes;
GLfloat constant_color[4] = {0.0, 0.0, 0.0, 1.0};
GLfloat constant_color[4] = {0.0, 0.0, 0.0, 0.0};
src_attributes = &setup->src.operand.texture.attributes;
@ -1134,7 +1189,7 @@ _cairo_gl_set_src_operand (cairo_gl_context_t *ctx,
case OPERAND_TEXTURE:
_cairo_gl_set_texture_surface (0, setup->src.operand.texture.tex,
src_attributes);
/* Set up the constant color we use to set alpha to 1 if needed. */
/* Set up the constant color we use to set color to 0 if needed. */
glTexEnvfv (GL_TEXTURE_ENV, GL_TEXTURE_ENV_COLOR, constant_color);
/* Set up the combiner to just set color to the sampled texture. */
glTexEnvi (GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_COMBINE);
@ -1150,16 +1205,7 @@ _cairo_gl_set_src_operand (cairo_gl_context_t *ctx,
glTexEnvi (GL_TEXTURE_ENV, GL_SRC0_RGB, GL_TEXTURE0);
else
glTexEnvi (GL_TEXTURE_ENV, GL_SRC0_RGB, GL_CONSTANT);
/* Wire the src alpha to 1 if the surface doesn't have it.
* We may have a teximage with alpha bits even though we didn't ask
* for it and we don't pay attention to setting alpha to 1 in a dest
* that has inadvertent alpha.
*/
if (setup->src.operand.texture.surface->base.content !=
CAIRO_CONTENT_COLOR)
glTexEnvi (GL_TEXTURE_ENV, GL_SRC0_ALPHA, GL_TEXTURE0);
else
glTexEnvi (GL_TEXTURE_ENV, GL_SRC0_ALPHA, GL_CONSTANT);
glTexEnvi (GL_TEXTURE_ENV, GL_SRC0_ALPHA, GL_TEXTURE0);
glTexEnvi (GL_TEXTURE_ENV, GL_OPERAND0_RGB, GL_SRC_COLOR);
glTexEnvi (GL_TEXTURE_ENV, GL_OPERAND0_ALPHA, GL_SRC_ALPHA);
break;
@ -1174,8 +1220,8 @@ static void
_cairo_gl_set_src_alpha_operand (cairo_gl_context_t *ctx,
cairo_gl_composite_setup_t *setup)
{
GLfloat constant_color[4] = {0.0, 0.0, 0.0, 0.0};
cairo_surface_attributes_t *src_attributes;
GLfloat constant_color[4];
src_attributes = &setup->src.operand.texture.attributes;
@ -1194,25 +1240,13 @@ _cairo_gl_set_src_alpha_operand (cairo_gl_context_t *ctx,
constant_color[3] = 1.0;
_cairo_gl_set_texture_surface (0, setup->src.operand.texture.tex,
src_attributes);
/* Set up the constant color we use to set alpha to 1 if needed. */
glTexEnvfv (GL_TEXTURE_ENV, GL_TEXTURE_ENV_COLOR, constant_color);
/* Set up the combiner to just set color to the sampled texture. */
glTexEnvi (GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_COMBINE);
glTexEnvi (GL_TEXTURE_ENV, GL_COMBINE_RGB, GL_REPLACE);
glTexEnvi (GL_TEXTURE_ENV, GL_COMBINE_ALPHA, GL_REPLACE);
/* Wire the src alpha to 1 if the surface doesn't have it.
* We may have a teximage with alpha bits even though we didn't ask
* for it and we don't pay attention to setting alpha to 1 in a dest
* that has inadvertent alpha.
*/
if (setup->src.operand.texture.surface->base.content != CAIRO_CONTENT_COLOR) {
glTexEnvi (GL_TEXTURE_ENV, GL_SRC0_RGB, GL_TEXTURE0);
glTexEnvi (GL_TEXTURE_ENV, GL_SRC0_ALPHA, GL_TEXTURE0);
} else {
glTexEnvi (GL_TEXTURE_ENV, GL_SRC0_RGB, GL_CONSTANT);
glTexEnvi (GL_TEXTURE_ENV, GL_SRC0_ALPHA, GL_CONSTANT);
}
glTexEnvi (GL_TEXTURE_ENV, GL_SRC0_RGB, GL_TEXTURE0);
glTexEnvi (GL_TEXTURE_ENV, GL_SRC0_ALPHA, GL_TEXTURE0);
glTexEnvi (GL_TEXTURE_ENV, GL_OPERAND0_RGB, GL_SRC_ALPHA);
glTexEnvi (GL_TEXTURE_ENV, GL_OPERAND0_ALPHA, GL_SRC_ALPHA);
break;
@ -1227,7 +1261,7 @@ _cairo_gl_set_component_alpha_mask_operand (cairo_gl_context_t *ctx,
cairo_gl_composite_setup_t *setup)
{
cairo_surface_attributes_t *mask_attributes;
GLfloat constant_color[4] = {0.0, 0.0, 0.0, 1.0};
GLfloat constant_color[4] = {0.0, 0.0, 0.0, 0.0};
mask_attributes = &setup->mask.operand.texture.attributes;
@ -1259,7 +1293,7 @@ _cairo_gl_set_component_alpha_mask_operand (cairo_gl_context_t *ctx,
case OPERAND_TEXTURE:
_cairo_gl_set_texture_surface (1, setup->mask.operand.texture.tex,
mask_attributes);
/* Set up the constant color we use to set alpha to 1 if needed. */
/* Set up the constant color we use to set color to 0 if needed. */
glTexEnvfv (GL_TEXTURE_ENV, GL_TEXTURE_ENV_COLOR, constant_color);
/* Force the mask color to 0 if the surface should be alpha-only.
@ -1271,16 +1305,7 @@ _cairo_gl_set_component_alpha_mask_operand (cairo_gl_context_t *ctx,
glTexEnvi (GL_TEXTURE_ENV, GL_SRC0_RGB, GL_TEXTURE1);
else
glTexEnvi (GL_TEXTURE_ENV, GL_SRC0_RGB, GL_CONSTANT);
/* Wire the mask alpha to 1 if the surface doesn't have it.
* We may have a teximage with alpha bits even though we didn't ask
* for it and we don't pay attention to setting alpha to 1 in a dest
* that has inadvertent alpha.
*/
if (setup->mask.operand.texture.surface->base.content !=
CAIRO_CONTENT_COLOR)
glTexEnvi (GL_TEXTURE_ENV, GL_SRC0_ALPHA, GL_TEXTURE1);
else
glTexEnvi (GL_TEXTURE_ENV, GL_SRC0_ALPHA, GL_CONSTANT);
glTexEnvi (GL_TEXTURE_ENV, GL_SRC0_ALPHA, GL_TEXTURE1);
glTexEnvi (GL_TEXTURE_ENV, GL_OPERAND0_RGB, GL_SRC_COLOR);
glTexEnvi (GL_TEXTURE_ENV, GL_OPERAND0_ALPHA, GL_SRC_ALPHA);
break;
@ -2344,13 +2369,7 @@ _cairo_gl_surface_paint (void *abstract_surface,
{
/* simplify the common case of clearing the surface */
if (op == CAIRO_OPERATOR_CLEAR && clip == NULL) {
cairo_gl_surface_t *surface = abstract_surface;
cairo_gl_context_t *ctx;
ctx = _cairo_gl_context_acquire (surface->ctx);
_cairo_gl_set_destination (surface);
glClear (GL_COLOR_BUFFER_BIT);
_cairo_gl_context_release (ctx);
_cairo_gl_surface_clear (abstract_surface);
return CAIRO_STATUS_SUCCESS;
}