allow switching the vao if we switch the style from plain color to pattern fill

2 files changed, 20 insertions, 14 deletions

diff --git a/include/llmr/geometry/elements_buffer.hpp b/include/llmr/geometry/elements_buffer.hpp
index 684b3acd3b..a058312bda 100644
--- a/include/llmr/geometry/elements_buffer.hpp
+++ b/include/llmr/geometry/elements_buffer.hpp
@@ -2,15 +2,12 @@
 #define LLMR_GEOMETRY_TRIANGLE_ELEMENTS_BUFFER
 
 #include <llmr/geometry/buffer.hpp>
+#include <llmr/geometry/vao.hpp>
 
 namespace llmr {
 
-template <typename Shader>
-class VertexArrayObject;
-
-template <typename Shader>
 struct ElementGroup {
-    VertexArrayObject<Shader> array;
+    VertexArrayObject array;
     uint32_t vertex_length;
     uint32_t elements_length;
 
diff --git a/include/llmr/geometry/vao.hpp b/include/llmr/geometry/vao.hpp
index a2a5a8a0d0..aa22e45e31 100644
--- a/include/llmr/geometry/vao.hpp
+++ b/include/llmr/geometry/vao.hpp
@@ -7,18 +7,26 @@
 
 namespace llmr {
 
-template <typename Shader>
 class VertexArrayObject {
 public:
-    template <typename VertexBuffer>
+    template <typename Shader, typename VertexBuffer>
     void bind(Shader& shader, VertexBuffer& vertex_buffer, char *offset) {
         if (!vao) {
             glGenVertexArrays(1, &vao);
             glBindVertexArray(vao);
+        } else {
+            // We have been given the correct information.
+            glBindVertexArray(vao);
+        }
 
+        if (shader_ptr != &shader) {
+            if (shader_ptr != nullptr) {
+                fprintf(stderr, "shader rebind!");
+            }
             vertex_buffer.bind();
             shader.bind(offset);
 
+            shader_ptr = &shader;
             vertex_buffer_ptr = &vertex_buffer;
             elements_buffer_ptr = nullptr;
             offset_ptr = offset;
@@ -28,22 +36,25 @@ public:
             throw std::runtime_error("trying to bind VAO to another elements buffer");
         } else if (offset_ptr != offset) {
             throw std::runtime_error("trying to bind VAO to another offset");
-        } else {
-            // We have been given the correct information.
-            glBindVertexArray(vao);
         }
     }
 
-    template <typename VertexBuffer, typename ElementsBuffer>
+    template <typename Shader, typename VertexBuffer, typename ElementsBuffer>
     void bind(Shader& shader, VertexBuffer& vertex_buffer, ElementsBuffer& elements_buffer, char *offset) {
         if (!vao) {
             glGenVertexArrays(1, &vao);
             glBindVertexArray(vao);
+        } else {
+            // We have been given the correct information.
+            glBindVertexArray(vao);
+        }
 
+        if (shader_ptr != &shader) {
             vertex_buffer.bind();
             elements_buffer.bind();
             shader.bind(offset);
 
+            shader_ptr = &shader;
             vertex_buffer_ptr = &vertex_buffer;
             elements_buffer_ptr = &elements_buffer;
             offset_ptr = offset;
@@ -53,9 +64,6 @@ public:
             throw std::runtime_error("trying to bind VAO to another elements buffer");
         } else if (offset_ptr != offset) {
             throw std::runtime_error("trying to bind VAO to another offset");
-        } else {
-            // We have been given the correct information.
-            glBindVertexArray(vao);
         }
     }
 
@@ -70,6 +78,7 @@ private:
 
     // For debug reasons, we're storing the bind information so that we can
     // detect errors and report
+    void *shader_ptr = nullptr;
     void *vertex_buffer_ptr = nullptr;
     void *elements_buffer_ptr = nullptr;
     char *offset_ptr = 0;