Update thumbnail generation to implement blending

src/canvas.cpp

@@ -2,6 +2,7 @@
 #include "log.h"
 #include "canvas.h"
 #include "app.h"
+#include "texture.h"
 #include "node_progress_bar.h"
 #include <thread>
 
@@ -1291,6 +1292,7 @@ void Canvas::export_equirectangular_thread(std::string file_path)
         ShaderManager::u_mat4(kShaderUniform::MVP, glm::ortho(-.5f, .5f, -.5f, .5f, -1.f, 1.f));
 
         m_tmp[i].bindFramebuffer();
+        // clear transparent not to mess with blending modes
         m_tmp[i].clear({ 1, 1, 1, 0 });
 
         glActiveTexture(GL_TEXTURE2);
@@ -1300,7 +1302,9 @@ void Canvas::export_equirectangular_thread(std::string file_path)
         m_sampler_bg.bind(2);
         for (auto layer_index : m_order)
         {
-            if (!m_layers[layer_index].m_visible || m_layers[layer_index].m_opacity == 0.f)
+            if (!m_layers[layer_index].m_visible ||
+                m_layers[layer_index].m_opacity == 0.f ||
+                !m_layers[layer_index].m_dirty_face)
                 continue;
             glActiveTexture(GL_TEXTURE2);
             glCopyTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, 0, 0, m_width, m_height);
@@ -1318,6 +1322,7 @@ void Canvas::export_equirectangular_thread(std::string file_path)
         glActiveTexture(GL_TEXTURE2);
         face.unbind();
 
+        // now blend with the background
         glEnable(GL_BLEND);
         ShaderManager::use(kShader::Texture);
         ShaderManager::u_int(kShaderUniform::Tex, 0);
@@ -1325,6 +1330,7 @@ void Canvas::export_equirectangular_thread(std::string file_path)
         m_sampler_mask.bind(0); // linear
         glActiveTexture(GL_TEXTURE0);
         face.bind();
+        // copy the framebuffer before clearing to white
         glCopyTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, 0, 0, m_width, m_height);
         m_tmp[i].clear({ 1, 1, 1, 1 });
         m_plane.draw_fill();
@@ -2047,7 +2053,6 @@ bool Canvas::project_open_thread(std::string file_path)
 
 Image Canvas::thumbnail_generate(int w, int h)
 {
-    
     // save viewport and clear color states
     GLint vp[4];
     GLfloat cc[4];
@@ -2061,33 +2066,69 @@ Image Canvas::thumbnail_generate(int w, int h)
     RTT fb;
     fb.create(w, h);
     fb.bindFramebuffer();
-    fb.clear({ 1, 1, 1, 1 });
     Plane m_face_plane;
     m_face_plane.create<1>(2, 2);
+    Texture2D blendtex;
+    blendtex.create(w, h);
 
     // recalculate because of different aspect ratio than the m_proj matrix
     glm::mat4 proj = glm::perspective(glm::radians(m_cam_fov), (float)w / (float)h, 0.1f, 1000.f);
 
-    glEnable(GL_BLEND);
+    fb.clear({ 1, 1, 1, 0 });
-    for (int plane_index = 0; plane_index < 6; plane_index++)
+    for (int i = 0; i < 6; i++)
     {
-        auto plane_mvp = proj * m_mv * m_plane_transform[plane_index] * glm::translate(glm::vec3(0, 0, -1));
+        glDisable(GL_BLEND);
+        auto plane_mvp = proj * m_mv * m_plane_transform[i] * glm::translate(glm::vec3(0, 0, -1));
 
+        ShaderManager::use(kShader::TextureBlend);
+        ShaderManager::u_int(kShaderUniform::Tex, 0);
+        ShaderManager::u_int(kShaderUniform::TexA, 1);
+        ShaderManager::u_int(kShaderUniform::TexBG, 2);
+        ShaderManager::u_mat4(kShaderUniform::MVP, plane_mvp);
+        glActiveTexture(GL_TEXTURE2);
+        blendtex.bind();
+        m_sampler_bg.bind(0);   // nearest
+        m_sampler_mask.bind(1); // linear
+        m_sampler_bg.bind(2);
+        for (auto layer_index : m_order)
+        {
+            if (!m_layers[layer_index].m_visible ||
+                m_layers[layer_index].m_opacity == 0.f ||
+                !m_layers[layer_index].m_dirty_face)
+                continue;
+            glActiveTexture(GL_TEXTURE2);
+            glCopyTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, 0, 0, w, h);
+            ShaderManager::u_int(kShaderUniform::BlendMode, m_layers[layer_index].m_blend_mode);
+            ShaderManager::u_float(kShaderUniform::Alpha, m_layers[layer_index].m_opacity);
+            glActiveTexture(GL_TEXTURE0);
+            m_layers[layer_index].m_rtt[i].bindTexture();
+            glActiveTexture(GL_TEXTURE1);
+            m_layers[layer_index].m_rtt[i].bindTexture();
+            m_face_plane.draw_fill();
+            m_layers[layer_index].m_rtt[i].unbindTexture();
+            glActiveTexture(GL_TEXTURE0);
+            m_layers[layer_index].m_rtt[i].unbindTexture();
+        }
+
+        // copy the framebuffer before clearing to white
+        glActiveTexture(GL_TEXTURE2);
+        glCopyTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, 0, 0, w, h);
+
+        // draw the grid
         ShaderManager::use(kShader::Checkerboard);
         ShaderManager::u_mat4(kShaderUniform::MVP, plane_mvp);
         m_face_plane.draw_fill();
 
-        ShaderManager::use(kShader::TextureAlpha);
+        // now blend with the background
+        glEnable(GL_BLEND);
+        ShaderManager::use(kShader::Texture);
         ShaderManager::u_int(kShaderUniform::Tex, 0);
-        ShaderManager::u_int(kShaderUniform::Highlight, false);
+        ShaderManager::u_mat4(kShaderUniform::MVP, glm::ortho(-.5f, .5f, -.5f, .5f, -1.f, 1.f));
-        ShaderManager::u_mat4(kShaderUniform::MVP, plane_mvp);
+        m_sampler_mask.bind(0); // linear
-        for (auto layer_index : m_order)
+        glActiveTexture(GL_TEXTURE0);
-        {
+        blendtex.bind();
-            ShaderManager::u_float(kShaderUniform::Alpha, m_layers[layer_index].m_opacity);
+        m_plane.draw_fill();
-            m_layers[layer_index].m_rtt[plane_index].bindTexture();
+        blendtex.unbind();
-            m_face_plane.draw_fill();
-            m_layers[layer_index].m_rtt[plane_index].unbindTexture();
-        }
     }
 
     fb.unbindFramebuffer();
@@ -2098,6 +2139,7 @@ Image Canvas::thumbnail_generate(int w, int h)
     fb.readTextureData((uint8_t*)image.data());
 
     fb.destroy();
+    blendtex.destroy();
 
     // restore viewport and clear color states
     blend ? glEnable(GL_BLEND) : glDisable(GL_BLEND);