move brush opacity from comp to stroke

data/shaders/comp-draw.glsl

@@ -23,7 +23,6 @@ uniform sampler2D tex;
 uniform sampler2D tex_stroke;
 uniform sampler2D tex_mask;
 uniform mediump float alpha;
-uniform mediump float stroke_alpha;
 uniform int blend_mode;
 uniform mediump vec2 resolution;
 uniform bool lock;
@@ -81,7 +80,7 @@ void main()
         stroke.a = blend_stroke(stroke.a, dual.a, dual_alpha, dual_blend_mode);
     }
 
-    stroke.a = mask ? stroke.a * stroke_alpha * blur(tex_mask, uv).r : stroke.a * stroke_alpha;
+    stroke.a = mask ? stroke.a * blur(tex_mask, uv).r : stroke.a;
     if (!lock && base.a == 0.0)
     {
         frag = stroke * vec4(1.0, 1.0, 1.0, alpha);

data/shaders/comp-erase.glsl

@@ -20,7 +20,6 @@ uniform sampler2D tex;
 uniform sampler2D tex_stroke;
 uniform sampler2D tex_mask;
 uniform mediump float alpha;
-uniform mediump float stroke_alpha;
 uniform mediump vec2 resolution;
 uniform bool mask;
 
@@ -31,6 +30,6 @@ void main()
 {
     mediump vec4 base = texture(tex, uv);
     mediump vec4 stroke = texture(tex_stroke, uv);
-    stroke.a = mask ? stroke.a * stroke_alpha * blur(tex_mask, uv).r : stroke.a * stroke_alpha;
+    stroke.a = mask ? stroke.a * blur(tex_mask, uv).r : stroke.a;
     frag = vec4(base.rgb, clamp((base.a - stroke.a) * alpha, 0.0, 1.0));
 }

data/shaders/stroke.glsl

@@ -30,6 +30,7 @@ uniform mediump sampler2D tex_mix;
 uniform mediump vec4 col;
 uniform mediump vec2 resolution;
 uniform mediump float alpha;
+uniform mediump float opacity;
 uniform mediump float noise;
 uniform mediump float mix_alpha;
 uniform mediump float wet;
@@ -99,11 +100,11 @@ void main()
         fg.rgb = mix(fg.rgb, mbg.rgb, mix_alpha * mbg.a);
     }
 
-    mediump float contribution = (1.0 - bg.a) * fg.a;
+    mediump float contribution = (opacity - bg.a) * fg.a;
     mediump float alpha_tot = bg.a + contribution;
     mediump vec3 rgb = mix(bg.rgb, fg.rgb, fg.a / alpha_tot);
     mediump vec4 frag_wet = vec4(rgb, max(bg.a, fg.a * 1.2));
-    mediump vec4 frag_dry = vec4(rgb, alpha_tot);
+    mediump vec4 frag_dry = vec4(rgb, min(alpha_tot, opacity));
     frag = mix(frag_dry, frag_wet, wet);
 }
 

src/app_vr.cpp

@@ -66,7 +66,6 @@ void App::vr_draw(const glm::mat4& proj, const glm::mat4& camera, const glm::mat
                 ShaderManager::u_int(kShaderUniform::Tex, 0);
                 ShaderManager::u_int(kShaderUniform::TexStroke, 1);
                 ShaderManager::u_int(kShaderUniform::TexMask, 2);
-                ShaderManager::u_float(kShaderUniform::StrokeAlpha, canvas->m_canvas->m_current_stroke->m_brush->m_tip_opacity);
                 ShaderManager::u_float(kShaderUniform::Alpha, canvas->m_canvas->m_layers[layer_index]->m_opacity);
                 //ShaderManager::u_int(kShaderUniform::Lock, m_canvas->m_layers[layer_index]->m_alpha_locked);
                 ShaderManager::u_int(kShaderUniform::Mask, canvas->m_canvas->m_smask_active);
@@ -99,7 +98,6 @@ void App::vr_draw(const glm::mat4& proj, const glm::mat4& camera, const glm::mat
                 ShaderManager::u_int(kShaderUniform::TexMask, 2);
                 ShaderManager::u_vec2(kShaderUniform::Resolution, canvas->m_canvas->m_size);
                 ShaderManager::u_int(kShaderUniform::TexPattern, 3);
-                ShaderManager::u_float(kShaderUniform::StrokeAlpha, b->m_tip_opacity);
                 ShaderManager::u_float(kShaderUniform::Alpha, canvas->m_canvas->m_layers[layer_index]->m_opacity);
                 ShaderManager::u_int(kShaderUniform::Lock, canvas->m_canvas->m_layers[layer_index]->m_alpha_locked);
                 ShaderManager::u_int(kShaderUniform::Mask, canvas->m_canvas->m_smask_active);

src/canvas.cpp

@@ -248,7 +248,6 @@ void Canvas::stroke_draw_mix(const glm::vec2& bb_min, const glm::vec2& bb_sz)
         ShaderManager::u_int(kShaderUniform::TexMask, 2);
         ShaderManager::u_vec2(kShaderUniform::Resolution, m_size);
         ShaderManager::u_int(kShaderUniform::TexPattern, 3);
-        ShaderManager::u_float(kShaderUniform::StrokeAlpha, b->m_tip_opacity);
         ShaderManager::u_float(kShaderUniform::Alpha, 1);
         ShaderManager::u_int(kShaderUniform::Lock, false/*m_layers[layer_index]->m_alpha_locked*/);
         ShaderManager::u_int(kShaderUniform::Mask, false/*m_smask_active*/);
@@ -495,6 +494,7 @@ void Canvas::stroke_draw()
     ShaderManager::u_int(kShaderUniform::TexPattern, 2); // pattern
     ShaderManager::u_int(kShaderUniform::TexMix, 3); // mixer
     //ShaderManager::u_int(kShaderUniform::TexMixA, 4); // mixer
+    ShaderManager::u_float(kShaderUniform::Opacity, brush->m_tip_opacity);
     ShaderManager::u_vec2(kShaderUniform::Resolution, { m_width, m_height });
     ShaderManager::u_vec2(kShaderUniform::PatternScale, patt_scale);
     ShaderManager::u_float(kShaderUniform::PatternInvert, brush->m_pattern_invert);
@@ -529,6 +529,7 @@ void Canvas::stroke_draw()
         ShaderManager::use(kShader::Stroke);
         ShaderManager::u_vec4(kShaderUniform::Col, f.col);
         ShaderManager::u_float(kShaderUniform::Alpha, f.pressure);
+        //ShaderManager::u_float(kShaderUniform::Opacity, f.opacity); // per-tip opacity
         for (int i = 0; i < 6; i++)
         {
             auto& P = f.shapes[i];
@@ -548,12 +549,14 @@ void Canvas::stroke_draw()
 
     // DRAW DUAL BRUSH
 
-    ShaderManager::u_int(kShaderUniform::UsePattern, false);
-    ShaderManager::u_float(kShaderUniform::MixAlpha, 0);
-    ShaderManager::u_float(kShaderUniform::Wet, 0);
-    ShaderManager::u_float(kShaderUniform::Noise, 0);
     if (brush->m_dual_enabled)
     {
+        ShaderManager::u_int(kShaderUniform::UsePattern, false);
+        ShaderManager::u_float(kShaderUniform::Opacity, brush->m_dual_opacity);
+        ShaderManager::u_float(kShaderUniform::MixAlpha, 0);
+        ShaderManager::u_float(kShaderUniform::Wet, 0);
+        ShaderManager::u_float(kShaderUniform::Noise, 0);
+        
         glActiveTexture(GL_TEXTURE0);
         dual_brush->m_tip_texture->bind();
         auto frames_dual = stroke_draw_compute(*m_dual_stroke);
@@ -562,6 +565,7 @@ void Canvas::stroke_draw()
             ShaderManager::use(kShader::Stroke);
             ShaderManager::u_vec4(kShaderUniform::Col, f.col);
             ShaderManager::u_float(kShaderUniform::Alpha, f.pressure);
+            //ShaderManager::u_float(kShaderUniform::Opacity, f.opacity); // per-tip opacity
             for (int i = 0; i < 6; i++)
             {
                 auto& P = f.shapes[i];
@@ -769,7 +773,6 @@ void Canvas::stroke_commit()
             ShaderManager::u_int(kShaderUniform::TexStroke, 1);
             ShaderManager::u_int(kShaderUniform::TexMask, 2);
             ShaderManager::u_int(kShaderUniform::Mask, m_smask_active);
-            ShaderManager::u_float(kShaderUniform::StrokeAlpha, b->m_tip_opacity);
             ShaderManager::u_float(kShaderUniform::Alpha, 1);
             ShaderManager::u_mat4(kShaderUniform::MVP, glm::ortho(-.5f, .5f, -.5f, .5f, -1.f, 1.f));
 
@@ -799,7 +802,6 @@ void Canvas::stroke_commit()
             ShaderManager::u_int(kShaderUniform::TexDual, 3);
             ShaderManager::u_int(kShaderUniform::TexPattern, 4);
             ShaderManager::u_vec2(kShaderUniform::Resolution, m_size);
-            ShaderManager::u_float(kShaderUniform::StrokeAlpha, b->m_tip_opacity);
             ShaderManager::u_float(kShaderUniform::Alpha, 1);
             ShaderManager::u_int(kShaderUniform::Mask, m_smask_active);
             //ShaderManager::u_int(kShaderUniform::DrawOnScreen, false);
@@ -1020,7 +1022,6 @@ void Canvas::layer_merge(int source_idx, int dest_idx) // m_layer index
             ShaderManager::u_int(kShaderUniform::Tex, 0); // dest
             ShaderManager::u_int(kShaderUniform::TexStroke, 1); // source
             ShaderManager::u_vec2(kShaderUniform::Resolution, m_size);
-            ShaderManager::u_float(kShaderUniform::StrokeAlpha, 1);
             ShaderManager::u_float(kShaderUniform::PatternAlpha, 0);
             ShaderManager::u_float(kShaderUniform::Alpha, m_layers[source_idx]->m_opacity);
             ShaderManager::u_int(kShaderUniform::Lock, false);

src/canvas_modes.cpp

@@ -1157,7 +1157,6 @@ void CanvasModeTransform::leave()
     ShaderManager::u_int(kShaderUniform::TexStroke, 1);
     ShaderManager::u_int(kShaderUniform::TexMask, 2);
     ShaderManager::u_float(kShaderUniform::Alpha, 1);
-    ShaderManager::u_float(kShaderUniform::StrokeAlpha, 1);
     ShaderManager::u_int(kShaderUniform::Lock, false);
     ShaderManager::u_int(kShaderUniform::Mask, false);
     ShaderManager::u_vec2(kShaderUniform::Resolution, Canvas::I->m_size);

src/node_canvas.cpp

@@ -182,7 +182,6 @@ void NodeCanvas::draw()
                 ShaderManager::u_int(kShaderUniform::TexStroke, 1);
                 ShaderManager::u_int(kShaderUniform::TexMask, 2);
                 //ShaderManager::u_vec2(kShaderUniform::Resolution, zw(m_canvas->m_box) / zoom);
-                ShaderManager::u_float(kShaderUniform::StrokeAlpha, b->m_tip_opacity);
                 ShaderManager::u_float(kShaderUniform::Alpha, m_canvas->m_layers[layer_index]->m_opacity);
                 //ShaderManager::u_int(kShaderUniform::Lock, m_canvas->m_layers[layer_index]->m_alpha_locked);
                 ShaderManager::u_int(kShaderUniform::Mask, m_canvas->m_smask_active);
@@ -215,7 +214,6 @@ void NodeCanvas::draw()
                 ShaderManager::u_int(kShaderUniform::TexDual, 3);
                 ShaderManager::u_vec2(kShaderUniform::Resolution, Canvas::I->m_size);
                 ShaderManager::u_int(kShaderUniform::TexPattern, 4);
-                ShaderManager::u_float(kShaderUniform::StrokeAlpha, b->m_tip_opacity);
                 ShaderManager::u_float(kShaderUniform::Alpha, m_canvas->m_layers[layer_index]->m_opacity);
                 ShaderManager::u_int(kShaderUniform::Lock, m_canvas->m_layers[layer_index]->m_alpha_locked);
                 ShaderManager::u_int(kShaderUniform::Mask, m_canvas->m_smask_active);

src/node_stroke_preview.cpp

@@ -80,7 +80,6 @@ void NodeStrokePreview::stroke_draw_mix(const glm::vec2& bb_min, const glm::vec2
     ShaderManager::u_int(kShaderUniform::TexDual, 3);
     ShaderManager::u_int(kShaderUniform::TexPattern, 4);
     ShaderManager::u_vec2(kShaderUniform::Resolution, m_size);
-    ShaderManager::u_float(kShaderUniform::StrokeAlpha, b->m_tip_opacity);
     ShaderManager::u_float(kShaderUniform::Alpha, 1);
     ShaderManager::u_int(kShaderUniform::Lock, false);
     ShaderManager::u_int(kShaderUniform::Mask, false);
@@ -320,6 +319,7 @@ void NodeStrokePreview::draw_stroke()
         m_rtt.clear();
         ShaderManager::use(kShader::Stroke);
         ShaderManager::u_int(kShaderUniform::UsePattern, false);
+        ShaderManager::u_float(kShaderUniform::Opacity, b->m_dual_opacity);
         ShaderManager::u_float(kShaderUniform::MixAlpha, 0);
         ShaderManager::u_float(kShaderUniform::Wet, 0);
         ShaderManager::u_float(kShaderUniform::Noise, 0);
@@ -328,8 +328,9 @@ void NodeStrokePreview::draw_stroke()
         auto frames_dual = stroke_draw_compute(m_dual_stroke);
         for (auto& f : frames_dual)
         {
-            ShaderManager::u_vec4(kShaderUniform::Col, f.col);
+            ShaderManager::u_vec4(kShaderUniform::Col, { 0, 0, 0, 1 });
             ShaderManager::u_float(kShaderUniform::Alpha, f.pressure);
+            //ShaderManager::u_float(kShaderUniform::Opacity, f.opacity); // per sample opacity
             auto rect = stroke_draw_samples(f.shapes, m_tex_dual);
         }
         glActiveTexture(GL_TEXTURE0);
@@ -344,6 +345,7 @@ void NodeStrokePreview::draw_stroke()
     // DRAW MAIN BRUSH
 
     ShaderManager::use(kShader::Stroke);
+    ShaderManager::u_float(kShaderUniform::Opacity, b->m_tip_opacity);
     ShaderManager::u_float(kShaderUniform::MixAlpha, b->m_tip_mix);
     ShaderManager::u_float(kShaderUniform::Wet, b->m_tip_wet);
     ShaderManager::u_float(kShaderUniform::Noise, b->m_tip_noise);
@@ -369,6 +371,7 @@ void NodeStrokePreview::draw_stroke()
         ShaderManager::use(kShader::Stroke);
         ShaderManager::u_vec4(kShaderUniform::Col, { 0, 0, 0, 1 } /*f.col*/);
         ShaderManager::u_float(kShaderUniform::Alpha, glm::max(f.pressure, m_min_flow));
+        //ShaderManager::u_float(kShaderUniform::Opacity, f.opacity); // per sample opacity
         auto rect = stroke_draw_samples(f.shapes, m_tex);
     }
     glActiveTexture(GL_TEXTURE3);
@@ -400,7 +403,6 @@ void NodeStrokePreview::draw_stroke()
     ShaderManager::u_int(kShaderUniform::TexDual, 3);
     ShaderManager::u_int(kShaderUniform::TexPattern, 4);
     ShaderManager::u_vec2(kShaderUniform::Resolution, size);
-    ShaderManager::u_float(kShaderUniform::StrokeAlpha, b->m_tip_opacity);
     ShaderManager::u_float(kShaderUniform::Alpha, 1);
     //ShaderManager::u_int(kShaderUniform::DrawOnScreen, false);
     ShaderManager::u_int(kShaderUniform::Mask, false);

src/shader.h

@@ -17,7 +17,7 @@ enum class kShaderUniform : uint16_t
     PatternOffset = const_hash("pattern_offset"),
     PatternAlpha = const_hash("pattern_alpha"),
     MixAlpha = const_hash("mix_alpha"),
-    StrokeAlpha = const_hash("stroke_alpha"),
+    Opacity = const_hash("opacity"),
     Wet = const_hash("wet"),
     Lock = const_hash("lock"),
     Col = const_hash("col"),