[gegl/soc-2013-n-point-deformation] libs: npd: add alpha blending
- From: Marek Dvoroznak <dvoromar src gnome org>
- To: commits-list gnome org
- Cc:
- Subject: [gegl/soc-2013-n-point-deformation] libs: npd: add alpha blending
- Date: Fri, 16 Aug 2013 02:28:11 +0000 (UTC)
commit 16224ac325504aa109a74b0610997adc29ed2121
Author: Marek Dvoroznak <dvoromar gmail com>
Date: Thu Aug 15 16:12:51 2013 +0200
libs: npd: add alpha blending
libs/npd/graphics.c | 33 +++++++++++++-
libs/npd/graphics.h | 114 ++++++++++++++++++++++++---------------------
operations/external/npd.c | 2 +-
3 files changed, 94 insertions(+), 55 deletions(-)
---
diff --git a/libs/npd/graphics.c b/libs/npd/graphics.c
index e4f0878..ef0644d 100644
--- a/libs/npd/graphics.c
+++ b/libs/npd/graphics.c
@@ -183,6 +183,33 @@ npd_bilinear_color_interpolation (NPDColor *I0,
out->a = npd_bilinear_interpolation (I0->a, I1->a, I2->a, I3->a, dx, dy);
}
+gint
+npd_blend_band (gint src,
+ gint dst,
+ gfloat src_alpha,
+ gfloat dst_alpha,
+ gfloat out_alpha_recip)
+{
+ return floor ((src * src_alpha +
+ dst * dst_alpha * (1 - src_alpha)) * out_alpha_recip);
+}
+
+void
+npd_blend_colors (NPDColor *src,
+ NPDColor *dst,
+ NPDColor *out_color)
+{
+ gfloat src_A = src->a / 255.0,
+ dst_A = dst->a / 255.0;
+ gfloat out_alpha = src_A + dst_A * (1 - src_A);
+ gfloat out_alpha_recip = 1 / out_alpha;
+
+ out_color->r = npd_blend_band (src->r, dst->r, src_A, dst_A, out_alpha_recip);
+ out_color->g = npd_blend_band (src->g, dst->g, src_A, dst_A, out_alpha_recip);
+ out_color->b = npd_blend_band (src->b, dst->b, src_A, dst_A, out_alpha_recip);
+ out_color->a = out_alpha * 255;
+}
+
void
npd_texture_fill_triangle (gint x1,
gint y1,
@@ -333,7 +360,7 @@ npd_draw_texture_line (gint x1,
for (x = x1; x <= x2; x++)
{
NPDPoint p, q;
- NPDColor I0, I1, I2, I3, interpolated;
+ NPDColor I0, I1, I2, I3, interpolated, dest;
q.x = x; q.y = y;
npd_apply_transformation(A, &q, &p);
@@ -350,6 +377,10 @@ npd_draw_texture_line (gint x1,
npd_get_pixel_color(input_image, fx+1, fy+1, &I3);
npd_bilinear_color_interpolation(&I0, &I1, &I2, &I3, dx, dy, &interpolated);
+ /* alpha blending */
+ npd_get_pixel_color (output_image, x, y, &dest);
+ npd_blend_colors (&interpolated, &dest, &interpolated);
+
npd_set_pixel_color (output_image, x, y, &interpolated);
}
}
diff --git a/libs/npd/graphics.h b/libs/npd/graphics.h
index 691ec4f..ba1c8f7 100644
--- a/libs/npd/graphics.h
+++ b/libs/npd/graphics.h
@@ -29,64 +29,72 @@ struct _NPDColor {
unsigned char a;
};
-void npd_create_model_from_image (NPDModel *model,
- NPDImage *image,
- gint square_size);
-void npd_create_mesh_from_image (NPDModel *model,
- gint width,
- gint height,
- gint position_x,
- gint position_y);
-void npd_draw_model (NPDModel *model,
+void npd_create_model_from_image (NPDModel *model,
+ NPDImage *image,
+ gint square_size);
+void npd_create_mesh_from_image (NPDModel *model,
+ gint width,
+ gint height,
+ gint position_x,
+ gint position_y);
+void npd_draw_model (NPDModel *model,
NPDDisplay *display);
-gboolean npd_load_image (NPDImage *image,
+gboolean npd_load_image (NPDImage *image,
const char *path);
-void npd_destroy_image (NPDImage *image);
-void npd_draw_image (NPDImage *image);
-void npd_texture_fill_triangle (gint x1,
- gint y1,
- gint x2,
- gint y2,
- gint x3,
- gint y3,
- NPDMatrix *A,
- NPDImage *input_image,
- NPDImage *output_image);
-void npd_texture_quadrilateral (NPDBone *reference_bone,
- NPDBone *current_bone,
- NPDImage *input_image,
- NPDImage *output_image);
-void npd_draw_texture_line (gint x1,
- gint x2,
- gint y,
- NPDMatrix *A,
+void npd_destroy_image (NPDImage *image);
+//void npd_draw_image (NPDImage *image);
+void npd_texture_fill_triangle (gint x1,
+ gint y1,
+ gint x2,
+ gint y2,
+ gint x3,
+ gint y3,
+ NPDMatrix *A,
NPDImage *input_image,
NPDImage *output_image);
-gint npd_bilinear_interpolation (gint I0,
- gint I1,
- gint I2,
- gint I3,
- gfloat dx,
- gfloat dy);
-void npd_bilinear_color_interpolation (NPDColor *I0,
- NPDColor *I1,
- NPDColor *I2,
- NPDColor *I3,
- gfloat dx,
- gfloat dy,
- NPDColor *out);
-void (*npd_get_pixel_color) (NPDImage *image,
- gint x,
- gint y,
- NPDColor *color);
-void (*npd_set_pixel_color) (NPDImage *image,
- gint x,
- gint y,
- NPDColor *color);
-gboolean npd_compare_colors (NPDColor *c1,
- NPDColor *c2);
-gboolean npd_is_color_transparent (NPDColor *color);
+void npd_texture_quadrilateral (NPDBone *reference_bone,
+ NPDBone *current_bone,
+ NPDImage *input_image,
+ NPDImage *output_image);
+void npd_draw_texture_line (gint x1,
+ gint x2,
+ gint y,
+ NPDMatrix *A,
+ NPDImage *input_image,
+ NPDImage *output_image);
+gint npd_bilinear_interpolation (gint I0,
+ gint I1,
+ gint I2,
+ gint I3,
+ gfloat dx,
+ gfloat dy);
+void npd_bilinear_color_interpolation (NPDColor *I0,
+ NPDColor *I1,
+ NPDColor *I2,
+ NPDColor *I3,
+ gfloat dx,
+ gfloat dy,
+ NPDColor *out);
+gint npd_blend_band (gint src,
+ gint dst,
+ gfloat src_alpha,
+ gfloat dest_alpha,
+ gfloat out_alpha);
+void npd_blend_colors (NPDColor *src,
+ NPDColor *dst,
+ NPDColor *out_color);
+void (*npd_get_pixel_color) (NPDImage *image,
+ gint x,
+ gint y,
+ NPDColor *color);
+void (*npd_set_pixel_color) (NPDImage *image,
+ gint x,
+ gint y,
+ NPDColor *color);
+gboolean npd_compare_colors (NPDColor *c1,
+ NPDColor *c2);
+gboolean npd_is_color_transparent (NPDColor *color);
gboolean npd_init_display (NPDDisplay *display);
void npd_destroy_display (NPDDisplay *display);
diff --git a/operations/external/npd.c b/operations/external/npd.c
index d8df11c..47839b1 100644
--- a/operations/external/npd.c
+++ b/operations/external/npd.c
@@ -127,7 +127,7 @@ npd_get_pixel_color_impl (NPDImage *image,
}
void
-npd_draw_model (NPDModel *model,
+npd_draw_model (NPDModel *model,
NPDDisplay *display)
{
NPDHiddenModel *hidden_model = model->hidden_model;
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