prepare to draw on multiple planes

engine/canvas.h

@@ -8,6 +8,44 @@
 
 NS_START
 
+class Layer
+{
+public:
+    RTT m_rtt[6];
+    bool m_visible = true;
+    bool m_locked = false;
+    float m_opacity = 1.f;
+    std::string m_name;
+    bool create(int width, int height, std::string name)
+    {
+        for (int i = 0; i < 6; i++)
+        {
+            m_rtt[i].create(width, height);
+            m_rtt[i].bindFramebuffer();
+            m_rtt[i].clear();
+            m_rtt[i].unbindFramebuffer();
+        }
+        return true;
+    }
+    void clear(const glm::vec4& c)
+    {
+        // push clear color state
+        GLfloat cc[4];
+        glGetFloatv(GL_COLOR_CLEAR_VALUE, cc);
+        glClearColor(c.r, c.g, c.b, c.a);
+        
+        for (int i = 0; i < 6; i++)
+        {
+            m_rtt[i].bindFramebuffer();
+            glClear(GL_COLOR_BUFFER_BIT);
+            m_rtt[i].unbindFramebuffer();
+        }
+        
+        // restore clear color state
+        glClearColor(cc[0], cc[1], cc[2], cc[3]);
+    }
+};
+
 class Canvas
 {
     Plane m_plane;
@@ -27,9 +65,12 @@ public:
     bool m_show_tmp = false;
     std::vector<Layer> m_layers;
     std::vector<int> m_order;
-    RTT m_tmp;
-    Texture2D m_tex;
-    Texture2D m_tex2;
+    glm::vec4 m_dirty_box[6];
+    RTT m_tmp[6];
+    Texture2D m_tex[6];
+    Texture2D m_tex2[6];
+    glm::vec3 m_plane_origin[6];
+    glm::vec3 m_plane_normal[6];
     Sampler m_sampler;
     Sampler m_sampler_bg;
     glm::vec2 m_cam_rot;
@@ -52,8 +93,9 @@ class ActionStroke : public Action
 {
 public:
     std::unique_ptr<Stroke> m_stroke;
-    std::unique_ptr<uint8_t[]> m_image;
-    glm::ivec4 m_box;
+    std::unique_ptr<uint8_t[]> m_image[6];
+    glm::ivec4 m_box[6];
+    bool m_dirty[6];
     int m_layer_idx;
     Canvas* m_canvas;
     virtual void run() override
@@ -62,12 +104,17 @@ public:
     }
     virtual void undo() override
     {
-        m_canvas->m_layers[m_layer_idx].m_rtt.bindTexture();
+        for (int i = 0; i < 6; i++)
+        {
+            // empty data
+            if (!m_image[i])
+                continue;
 
-        glm::vec2 box_sz = m_box.zw() - m_box.xy();
-        glTexSubImage2D(GL_TEXTURE_2D, 0, m_box.x, m_box.y, box_sz.x, box_sz.y, GL_RGBA, GL_UNSIGNED_BYTE, m_image.get());
-
-        m_canvas->m_layers[m_layer_idx].m_rtt.unbindTexture();
+            m_canvas->m_layers[m_layer_idx].m_rtt[i].bindTexture();
+            glm::vec2 box_sz = m_box[i].zw() - m_box[i].xy();
+            glTexSubImage2D(GL_TEXTURE_2D, 0, m_box[i].x, m_box[i].y, box_sz.x, box_sz.y, GL_RGBA, GL_UNSIGNED_BYTE, m_image[i].get());
+            m_canvas->m_layers[m_layer_idx].m_rtt[i].unbindTexture();
+        }
     }
 };