Initial blending mode.

2 files changed, 15 insertions, 1 deletions

diff --git a/source/blender/gpu/shaders/sculpt_paint/sculpt_paint_image_comp.glsl b/source/blender/gpu/shaders/sculpt_paint/sculpt_paint_image_comp.glsl
index 2d64d9f2699..4fea3dd353d 100644
--- a/source/blender/gpu/shaders/sculpt_paint/sculpt_paint_image_comp.glsl
+++ b/source/blender/gpu/shaders/sculpt_paint/sculpt_paint_image_comp.glsl
@@ -49,7 +49,10 @@ void main()
         // TODO: blend with color...
         float factor = SCULPT_hardness_factor(distance, step_data.hardness, step_data.radius);
         float curve_factor = SCULPT_curve_strength(factor, BRUSH_CURVE_PRESET);
-        color = max(color, paint_brush_buf.color * curve_factor);
+        vec4 final_paint_color = SCULPT_blend_color(
+            color, paint_brush_buf.color * curve_factor * step_data.strength);
+        final_paint_color *= paint_brush_buf.alpha;
+        color = SCULPT_blend_color(color, final_paint_color);
       }
     }
     if (color_read) {
diff --git a/source/blender/gpu/shaders/sculpt_paint/sculpt_paint_image_lib.glsl b/source/blender/gpu/shaders/sculpt_paint/sculpt_paint_image_lib.glsl
index 8ea29f4bbae..68ec47d7fd3 100644
--- a/source/blender/gpu/shaders/sculpt_paint/sculpt_paint_image_lib.glsl
+++ b/source/blender/gpu/shaders/sculpt_paint/sculpt_paint_image_lib.glsl
@@ -3,6 +3,17 @@
 /** \name Brush testing
  * \{ */
 
+vec4 SCULPT_blend_color(vec4 src1, vec4 src2)
+{
+  return src1 * (1.0 - src2.a) + src2;
+}
+
+/** \} */
+
+/* -------------------------------------------------------------------- */
+/** \name Brush testing
+ * \{ */
+
 float SCULPT_curve_strength(float factor, int curve_type)
 {
   if (factor > 1.0) {