[cairo] [PATCH] gl/msaa: Add full support for masking with the SOURCE operator
Martin Robinson
mrobinson at igalia.com
Fri Dec 28 16:46:33 PST 2012
Note that I'm not the original author. Thus, I've included the full
commit below.
commit 038ea9d46cd140da796c97b27107fab8d7bd9837
Author: Henry Song <henry.song at samsung.com>
Date: Tue Mar 13 08:43:24 2012 -0700
gl/msaa: Add full support for masking with the SOURCE operator
Since OpenGL does not have a means to represent a masking SOURCE
operation in one step, we use two steps combined with the ADD
operator.
diff --git a/src/cairo-gl-composite.c b/src/cairo-gl-composite.c
index fa62a87..6731886 100644
--- a/src/cairo-gl-composite.c
+++ b/src/cairo-gl-composite.c
@@ -629,24 +629,13 @@ _cairo_gl_composite_setup_clipping
(cairo_gl_composite_t *setup,
}
cairo_status_t
-_cairo_gl_composite_begin (cairo_gl_composite_t *setup,
- cairo_gl_context_t **ctx_out)
+_cairo_gl_switch_operands_and_operator (cairo_gl_composite_t *setup,
+ cairo_gl_context_t *ctx)
{
unsigned int dst_size, src_size, mask_size, vertex_size;
- cairo_gl_context_t *ctx;
cairo_status_t status;
- cairo_bool_t component_alpha;
cairo_gl_shader_t *shader;
-
- assert (setup->dst);
-
- status = _cairo_gl_context_acquire (setup->dst->base.device, &ctx);
- if (unlikely (status))
- return status;
-
- _cairo_gl_context_set_destination (ctx, setup->dst,
setup->multisample);
-
- glEnable (GL_BLEND);
+ cairo_bool_t component_alpha;
component_alpha =
setup->mask.type == CAIRO_GL_OPERAND_TEXTURE &&
@@ -654,40 +643,40 @@ _cairo_gl_composite_begin (cairo_gl_composite_t
*setup,
/* Do various magic for component alpha */
if (component_alpha) {
- status = _cairo_gl_composite_begin_component_alpha (ctx, setup);
- if (unlikely (status))
- goto FAIL;
- } else {
- if (ctx->pre_shader) {
- _cairo_gl_composite_flush (ctx);
- ctx->pre_shader = NULL;
- }
+ status = _cairo_gl_composite_begin_component_alpha (ctx, setup);
+ if (unlikely (status))
+ return status;
+ } else {
+ if (ctx->pre_shader) {
+ _cairo_gl_composite_flush (ctx);
+ ctx->pre_shader = NULL;
+ }
}
status = _cairo_gl_get_shader_by_type (ctx,
&setup->src,
&setup->mask,
setup->spans,
- component_alpha ?
+ component_alpha ?
CAIRO_GL_SHADER_IN_CA_SOURCE :
CAIRO_GL_SHADER_IN_NORMAL,
&shader);
if (unlikely (status)) {
- ctx->pre_shader = NULL;
- goto FAIL;
+ ctx->pre_shader = NULL;
+ return status;
}
if (ctx->current_shader != shader)
_cairo_gl_composite_flush (ctx);
status = CAIRO_STATUS_SUCCESS;
- dst_size = 2 * sizeof (GLfloat);
- src_size = _cairo_gl_operand_get_vertex_size (setup->src.type);
+ dst_size = 2 * sizeof (GLfloat);
+ src_size = _cairo_gl_operand_get_vertex_size (setup->src.type);
mask_size = _cairo_gl_operand_get_vertex_size (setup->mask.type);
vertex_size = dst_size + src_size + mask_size;
if (setup->spans)
- vertex_size += sizeof (GLfloat);
+ vertex_size += sizeof (GLfloat);
_cairo_gl_composite_setup_vbo (ctx, vertex_size);
@@ -700,15 +689,35 @@ _cairo_gl_composite_begin (cairo_gl_composite_t
*setup,
_cairo_gl_set_operator (ctx, setup->op, component_alpha);
if (_cairo_gl_context_is_flushed (ctx)) {
- if (ctx->pre_shader) {
- _cairo_gl_set_shader (ctx, ctx->pre_shader);
- _cairo_gl_composite_bind_to_shader (ctx, setup);
- }
- _cairo_gl_set_shader (ctx, shader);
- _cairo_gl_composite_bind_to_shader (ctx, setup);
+ if (ctx->pre_shader) {
+ _cairo_gl_set_shader (ctx, ctx->pre_shader);
+ _cairo_gl_composite_bind_to_shader (ctx, setup);
+ }
+ _cairo_gl_set_shader (ctx, shader);
+ _cairo_gl_composite_bind_to_shader (ctx, setup);
}
- status = _cairo_gl_composite_setup_clipping (setup, ctx, vertex_size);
+ return status;
+}
+
+cairo_status_t
+_cairo_gl_composite_begin (cairo_gl_composite_t *setup,
+ cairo_gl_context_t **ctx_out)
+{
+ cairo_gl_context_t *ctx;
+ cairo_status_t status;
+
+ assert (setup->dst);
+
+ status = _cairo_gl_context_acquire (setup->dst->base.device, &ctx);
+ if (unlikely (status))
+ return status;
+
+ _cairo_gl_context_set_destination (ctx, setup->dst,
setup->multisample);
+ glEnable (GL_BLEND);
+ _cairo_gl_switch_operands_and_operator (setup, ctx);
+
+ status = _cairo_gl_composite_setup_clipping (setup, ctx,
ctx->vertex_size);
if (unlikely (status))
goto FAIL;
@@ -938,13 +947,10 @@ _cairo_gl_composite_fini (cairo_gl_composite_t *setup)
}
cairo_status_t
-_cairo_gl_composite_init (cairo_gl_composite_t *setup,
- cairo_operator_t op,
- cairo_gl_surface_t *dst,
- cairo_bool_t assume_component_alpha)
+_cairo_gl_composite_set_operator (cairo_gl_composite_t *setup,
+ cairo_operator_t op,
+ cairo_bool_t assume_component_alpha)
{
- memset (setup, 0, sizeof (cairo_gl_composite_t));
-
if (assume_component_alpha) {
if (op != CAIRO_OPERATOR_CLEAR &&
op != CAIRO_OPERATOR_OVER &&
@@ -955,8 +961,26 @@ _cairo_gl_composite_init (cairo_gl_composite_t *setup,
return UNSUPPORTED ("unsupported operator");
}
- setup->dst = dst;
setup->op = op;
+ return CAIRO_STATUS_SUCCESS;
+}
+
+cairo_status_t
+_cairo_gl_composite_init (cairo_gl_composite_t *setup,
+ cairo_operator_t op,
+ cairo_gl_surface_t *dst,
+ cairo_bool_t assume_component_alpha)
+{
+ cairo_status_t status;
+
+ memset (setup, 0, sizeof (cairo_gl_composite_t));
+
+ status = _cairo_gl_composite_set_operator (setup, op,
+ assume_component_alpha);
+ if (status)
+ return status;
+
+ setup->dst = dst;
setup->clip_region = dst->clip_region;
return CAIRO_STATUS_SUCCESS;
diff --git a/src/cairo-gl-msaa-compositor.c b/src/cairo-gl-msaa-compositor.c
index 12c416f..d96d746 100644
--- a/src/cairo-gl-msaa-compositor.c
+++ b/src/cairo-gl-msaa-compositor.c
@@ -286,6 +286,74 @@ _cairo_gl_msaa_compositor_set_clip
(cairo_composite_rectangles_t *composite,
_cairo_gl_composite_set_clip (setup, composite->clip);
}
+/* Masking with the SOURCE operator requires two passes. In the first
+ * pass we use the mask as the source to get:
+ * result = (1 - ma) * dst
+ * In the second pass we use the add operator to achieve:
+ * result = (src * ma) + dst
+ * Combined this produces:
+ * result = (src * ma) + (1 - ma) * dst
+ */
+static cairo_int_status_t
+_cairo_gl_msaa_compositor_mask_source_operator (const
cairo_compositor_t *compositor,
+ cairo_composite_rectangles_t *composite)
+{
+ cairo_gl_composite_t setup;
+ cairo_gl_surface_t *dst = (cairo_gl_surface_t *) composite->surface;
+ cairo_gl_context_t *ctx = NULL;
+ cairo_int_status_t status;
+
+ status = _cairo_gl_composite_init (&setup,
+ CAIRO_OPERATOR_DEST_OUT,
+ dst,
+ FALSE /* assume_component_alpha */);
+ if (unlikely (status))
+ return status;
+ status = _cairo_gl_composite_set_source (&setup,
+ &composite->mask_pattern.base,
+ &composite->mask_sample_area,
+ &composite->bounded);
+ if (unlikely (status))
+ goto finish;
+ _cairo_gl_composite_set_clip (&setup, composite->clip);
+ _cairo_gl_composite_set_multisample (&setup);
+ status = _cairo_gl_composite_begin (&setup, &ctx);
+ if (unlikely (status))
+ goto finish;
+
+ _draw_int_rect (ctx, &setup, &composite->bounded);
+
+ /* Now draw the second pass. */
+ _cairo_gl_composite_set_operator (&setup, CAIRO_OPERATOR_ADD,
+ FALSE /* assume_component_alpha */);
+ if (unlikely (status))
+ goto finish;
+ status = _cairo_gl_composite_set_source (&setup,
+ &composite->source_pattern.base,
+ &composite->source_sample_area,
+ &composite->bounded);
+ if (unlikely (status))
+ goto finish;
+ status = _cairo_gl_composite_set_mask (&setup,
+ &composite->mask_pattern.base,
+ &composite->source_sample_area,
+ &composite->bounded);
+ if (unlikely (status))
+ goto finish;
+ status = _cairo_gl_switch_operands_and_operator (&setup, ctx);
+ if (unlikely (status))
+ goto finish;
+
+ _draw_int_rect (ctx, &setup, &composite->bounded);
+
+finish:
+ _cairo_gl_composite_fini (&setup);
+ if (ctx)
+ status = _cairo_gl_context_release (ctx, status);
+
+ return status;
+}
+
static cairo_int_status_t
_cairo_gl_msaa_compositor_mask (const cairo_compositor_t *compositor,
cairo_composite_rectangles_t *composite)
@@ -308,12 +376,13 @@ _cairo_gl_msaa_compositor_mask (const
cairo_compositor_t *compositor,
! _cairo_pattern_is_opaque (&composite->mask_pattern.base,
&composite->mask_sample_area)) {
- /* If the source is opaque the operation reduces to OVER. */
- if (_cairo_pattern_is_opaque (&composite->source_pattern.base,
- &composite->source_sample_area))
- op = CAIRO_OPERATOR_OVER;
- else
- return CAIRO_INT_STATUS_UNSUPPORTED;
+ if (! _cairo_pattern_is_opaque (&composite->source_pattern.base,
+ &composite->source_sample_area)) {
+ return _cairo_gl_msaa_compositor_mask_source_operator (compositor,
composite);
+ }
+
+ /* If the source is opaque the operation reduces to OVER. */
+ op = CAIRO_OPERATOR_OVER;
}
if (_should_use_unbounded_surface (composite)) {
@@ -713,7 +782,8 @@ _cairo_gl_msaa_compositor_glyphs (const
cairo_compositor_t *compositor,
info.font = scaled_font;
info.glyphs = glyphs;
info.num_glyphs = num_glyphs;
- info.use_mask = overlap || ! composite->is_bounded;
+ info.use_mask = overlap || ! composite->is_bounded ||
+ composite->op == CAIRO_OPERATOR_SOURCE;
info.extents = composite->bounded;
_cairo_scaled_font_freeze_cache (scaled_font);
diff --git a/src/cairo-gl-private.h b/src/cairo-gl-private.h
index 57242a4..1a4d40e 100644
--- a/src/cairo-gl-private.h
+++ b/src/cairo-gl-private.h
@@ -497,6 +497,11 @@ _cairo_gl_composite_init (cairo_gl_composite_t *setup,
cairo_private void
_cairo_gl_composite_fini (cairo_gl_composite_t *setup);
+cairo_status_t
+_cairo_gl_composite_set_operator (cairo_gl_composite_t *setup,
+ cairo_operator_t op,
+ cairo_bool_t assume_component_alpha);
+
cairo_private void
_cairo_gl_composite_set_clip_region (cairo_gl_composite_t *setup,
cairo_region_t *clip_region);
@@ -539,6 +544,10 @@ cairo_private cairo_status_t
_cairo_gl_composite_begin (cairo_gl_composite_t *setup,
cairo_gl_context_t **ctx);
+cairo_status_t
+_cairo_gl_switch_operands_and_operator (cairo_gl_composite_t *setup,
+ cairo_gl_context_t *ctx);
+
cairo_private void
_cairo_gl_composite_emit_rect (cairo_gl_context_t *ctx,
GLfloat x1,
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