AA branch: io.RenderDrawListsFn signature changed to take ImDrawData, neater and future proof breaking of the render API (#133 #254)

examples/directx11_example/imgui_impl_dx11.cpp

@@ -40,7 +40,7 @@ struct VERTEX_CONSTANT_BUFFER
 // This is the main rendering function that you have to implement and provide to ImGui (via setting up 'RenderDrawListsFn' in the ImGuiIO structure)
 // If text or lines are blurry when integrating ImGui in your engine:
 // - in your Render function, try translating your projection matrix by (0.5f,0.5f) or (0.375f,0.375f)
-static void ImGui_ImplDX11_RenderDrawLists(ImDrawList** const cmd_lists, int cmd_lists_count)
+static void ImGui_ImplDX11_RenderDrawLists(ImDrawData* draw_data)
 {
     // Copy and convert all vertices into a single contiguous buffer
     D3D11_MAPPED_SUBRESOURCE vtx_resource, idx_resource;
@@ -50,9 +50,9 @@ static void ImGui_ImplDX11_RenderDrawLists(ImDrawList** const cmd_lists, int cmd
         return;
     ImDrawVert* vtx_dst = (ImDrawVert*)vtx_resource.pData;
     ImDrawIdx* idx_dst = (ImDrawIdx*)idx_resource.pData;
-    for (int n = 0; n < cmd_lists_count; n++)
+    for (int n = 0; n < draw_data->cmd_lists_count; n++)
     {
-        const ImDrawList* cmd_list = cmd_lists[n];
+        const ImDrawList* cmd_list = draw_data->cmd_lists[n];
         memcpy(vtx_dst, &cmd_list->vtx_buffer[0], cmd_list->vtx_buffer.size() * sizeof(ImDrawVert));
         memcpy(idx_dst, &cmd_list->idx_buffer[0], cmd_list->idx_buffer.size() * sizeof(ImDrawIdx));
         vtx_dst += cmd_list->vtx_buffer.size();
@@ -116,9 +116,9 @@ static void ImGui_ImplDX11_RenderDrawLists(ImDrawList** const cmd_lists, int cmd
     // Render command lists
     int vtx_offset = 0;
     int idx_offset = 0;
-    for (int n = 0; n < cmd_lists_count; n++)
+    for (int n = 0; n < draw_data->cmd_lists_count; n++)
     {
-        const ImDrawList* cmd_list = cmd_lists[n];
+        const ImDrawList* cmd_list = draw_data->cmd_lists[n];
         for (size_t cmd_i = 0; cmd_i < cmd_list->commands.size(); cmd_i++)
         {
             const ImDrawCmd* pcmd = &cmd_list->commands[cmd_i];

examples/directx9_example/imgui_impl_dx9.cpp

@@ -30,28 +30,18 @@ struct CUSTOMVERTEX
 // This is the main rendering function that you have to implement and provide to ImGui (via setting up 'RenderDrawListsFn' in the ImGuiIO structure)
 // If text or lines are blurry when integrating ImGui in your engine:
 // - in your Render function, try translating your projection matrix by (0.5f,0.5f) or (0.375f,0.375f)
-static void ImGui_ImplDX9_RenderDrawLists(ImDrawList** const cmd_lists, int cmd_lists_count)
+static void ImGui_ImplDX9_RenderDrawLists(ImDrawData* draw_data)
 {
-    size_t total_vtx_count = 0;
-    size_t total_idx_count = 0;
-    for (int n = 0; n < cmd_lists_count; n++)
-    {
-        total_vtx_count += cmd_lists[n]->vtx_buffer.size();
-        total_idx_count += cmd_lists[n]->idx_buffer.size();
-    }
-    if (total_vtx_count == 0)
-        return;
-
     // Copy and convert all vertices into a single contiguous buffer
     CUSTOMVERTEX* vtx_dst;
     ImDrawIdx* idx_dst;
-    if (g_pVB->Lock(0, (UINT)(total_vtx_count * sizeof(CUSTOMVERTEX)), (void**)&vtx_dst, D3DLOCK_DISCARD) < 0)
+    if (g_pVB->Lock(0, (UINT)(draw_data->total_vtx_count * sizeof(CUSTOMVERTEX)), (void**)&vtx_dst, D3DLOCK_DISCARD) < 0)
         return;
-    if (g_pIB->Lock(0, (UINT)(total_idx_count * sizeof(ImDrawIdx)), (void**)&idx_dst, D3DLOCK_DISCARD) < 0)
+    if (g_pIB->Lock(0, (UINT)(draw_data->total_idx_count * sizeof(ImDrawIdx)), (void**)&idx_dst, D3DLOCK_DISCARD) < 0)
         return;
-    for (int n = 0; n < cmd_lists_count; n++)
+    for (int n = 0; n < draw_data->cmd_lists_count; n++)
     {
-        const ImDrawList* cmd_list = cmd_lists[n];
+        const ImDrawList* cmd_list = draw_data->cmd_lists[n];
         const ImDrawVert* vtx_src = &cmd_list->vtx_buffer[0];
         for (size_t i = 0; i < cmd_list->vtx_buffer.size(); i++)
         {
@@ -104,9 +94,9 @@ static void ImGui_ImplDX9_RenderDrawLists(ImDrawList** const cmd_lists, int cmd_
     // Render command lists
     int vtx_offset = 0;
     int idx_offset = 0;
-    for (int n = 0; n < cmd_lists_count; n++)
+    for (int n = 0; n < draw_data->cmd_lists_count; n++)
     {
-        const ImDrawList* cmd_list = cmd_lists[n];
+        const ImDrawList* cmd_list = draw_data->cmd_lists[n];
         for (size_t cmd_i = 0; cmd_i < cmd_list->commands.size(); cmd_i++)
         {
             const ImDrawCmd* pcmd = &cmd_list->commands[cmd_i];

examples/opengl3_example/imgui_impl_glfw_gl3.cpp

@@ -29,11 +29,8 @@ static unsigned int g_VboHandle = 0, g_VaoHandle = 0;
 // This is the main rendering function that you have to implement and provide to ImGui (via setting up 'RenderDrawListsFn' in the ImGuiIO structure)
 // If text or lines are blurry when integrating ImGui in your engine:
 // - in your Render function, try translating your projection matrix by (0.5f,0.5f) or (0.375f,0.375f)
-static void ImGui_ImplGlfwGL3_RenderDrawLists(ImDrawList** const cmd_lists, int cmd_lists_count)
+static void ImGui_ImplGlfwGL3_RenderDrawLists(ImDrawData* draw_data)
 {
-    if (cmd_lists_count == 0)
-        return;
-
     // Setup render state: alpha-blending enabled, no face culling, no depth testing, scissor enabled
     GLint last_program, last_texture;
     glGetIntegerv(GL_CURRENT_PROGRAM, &last_program);
@@ -61,11 +58,8 @@ static void ImGui_ImplGlfwGL3_RenderDrawLists(ImDrawList** const cmd_lists, int
     glUniformMatrix4fv(g_AttribLocationProjMtx, 1, GL_FALSE, &ortho_projection[0][0]);
 
     // Grow our buffer according to what we need
-    size_t total_vtx_count = 0;
-    for (int n = 0; n < cmd_lists_count; n++)
-        total_vtx_count += cmd_lists[n]->vtx_buffer.size();
     glBindBuffer(GL_ARRAY_BUFFER, g_VboHandle);
-    size_t needed_vtx_size = total_vtx_count * sizeof(ImDrawVert);
+    size_t needed_vtx_size = draw_data->total_vtx_count * sizeof(ImDrawVert);
     if (g_VboSize < needed_vtx_size)
     {
         g_VboSize = needed_vtx_size + 5000 * sizeof(ImDrawVert);  // Grow buffer
@@ -76,9 +70,9 @@ static void ImGui_ImplGlfwGL3_RenderDrawLists(ImDrawList** const cmd_lists, int
     unsigned char* vtx_data = (unsigned char*)glMapBuffer(GL_ARRAY_BUFFER, GL_WRITE_ONLY);
     if (!vtx_data)
         return;
-    for (int n = 0; n < cmd_lists_count; n++)
+    for (int n = 0; n < draw_data->cmd_lists_count; n++)
     {
-        const ImDrawList* cmd_list = cmd_lists[n];
+        const ImDrawList* cmd_list = draw_data->cmd_lists[n];
         memcpy(vtx_data, &cmd_list->vtx_buffer[0], cmd_list->vtx_buffer.size() * sizeof(ImDrawVert));
         vtx_data += cmd_list->vtx_buffer.size() * sizeof(ImDrawVert);
     }
@@ -87,9 +81,9 @@ static void ImGui_ImplGlfwGL3_RenderDrawLists(ImDrawList** const cmd_lists, int
     glBindVertexArray(g_VaoHandle);
 
     int vtx_offset = 0;
-    for (int n = 0; n < cmd_lists_count; n++)
+    for (int n = 0; n < draw_data->cmd_lists_count; n++)
     {
-        const ImDrawList* cmd_list = cmd_lists[n];
+        const ImDrawList* cmd_list = draw_data->cmd_lists[n];
         const ImDrawIdx* idx_buffer = (const unsigned short*)&cmd_list->idx_buffer.front();
 
         const ImDrawCmd* pcmd_end = cmd_list->commands.end();

examples/opengl_example/imgui_impl_glfw.cpp

@@ -23,11 +23,8 @@ static GLuint       g_FontTexture = 0;
 // This is the main rendering function that you have to implement and provide to ImGui (via setting up 'RenderDrawListsFn' in the ImGuiIO structure)
 // If text or lines are blurry when integrating ImGui in your engine:
 // - in your Render function, try translating your projection matrix by (0.5f,0.5f) or (0.375f,0.375f)
-static void ImGui_ImplGlfw_RenderDrawLists(ImDrawList** const cmd_lists, int cmd_lists_count)
+static void ImGui_ImplGlfw_RenderDrawLists(ImDrawData* draw_data)
 {
-    if (cmd_lists_count == 0)
-        return;
-
     // We are using the OpenGL fixed pipeline to make the example code simpler to read!
     // A probable faster way to render would be to collate all vertices from all cmd_lists into a single vertex buffer.
     // Setup render state: alpha-blending enabled, no face culling, no depth testing, scissor enabled, vertex/texcoord/color pointers.
@@ -56,9 +53,9 @@ static void ImGui_ImplGlfw_RenderDrawLists(ImDrawList** const cmd_lists, int cmd
 
     // Render command lists
     #define OFFSETOF(TYPE, ELEMENT) ((size_t)&(((TYPE *)0)->ELEMENT))
-    for (int n = 0; n < cmd_lists_count; n++)
+    for (int n = 0; n < draw_data->cmd_lists_count; n++)
     {
-        const ImDrawList* cmd_list = cmd_lists[n];
+        const ImDrawList* cmd_list = draw_data->cmd_lists[n];
         const unsigned char* vtx_buffer = (const unsigned char*)&cmd_list->vtx_buffer.front();
         const ImDrawIdx* idx_buffer = (const unsigned short*)&cmd_list->idx_buffer.front();
         glVertexPointer(2, GL_FLOAT, sizeof(ImDrawVert), (void*)(vtx_buffer + OFFSETOF(ImDrawVert, pos)));

imgui.cpp

@@ -141,6 +141,7 @@
  Occasionally introducing changes that are breaking the API. The breakage are generally minor and easy to fix.
  Here is a change-log of API breaking changes, if you are using one of the functions listed, expect to have to fix some code.
  
+ - 2015/07/05 (1.42) - io.RenderDrawListsFn signature changed from RenderDrawListsFn(ImDrawList** const cmd_lists, int cmd_lists_count) to RenderDrawListsFn(ImDrawData*). ImDrawData structure contains 'cmd_lists', 'cmd_lists_count' and more.
  - 2015/07/02 (1.42) - renamed SetScrollPosHere() to SetScrollFromCursorPos(). Kept inline redirection function (will obsolete).
  - 2015/07/02 (1.42) - renamed GetScrollPosY() to GetScrollY(). Necessary to reduce confusion along with other scrolling functions, because positions (e.g. cursor position) are not equivalent to scrolling amount.
  - 2015/06/14 (1.41) - changed ImageButton() default bg_col parameter from (0,0,0,1) (black) to (0,0,0,0) (transparent) - makes a difference when texture have transparence
@@ -2509,7 +2510,14 @@ void ImGui::Render()
 
         // Render
         if (!g.RenderDrawLists[0].empty())
-            g.IO.RenderDrawListsFn(&g.RenderDrawLists[0][0], (int)g.RenderDrawLists[0].size());
+        {
+            ImDrawData data;
+            data.cmd_lists = &g.RenderDrawLists[0][0];
+            data.cmd_lists_count = (int)g.RenderDrawLists[0].size();
+            data.total_vtx_count = g.IO.MetricsRenderVertices;
+            data.total_idx_count = g.IO.MetricsRenderIndices;
+            g.IO.RenderDrawListsFn(&data);
+        }
     }
 }
 

imgui.h

@@ -31,6 +31,7 @@
 // Forward declarations
 struct ImDrawCmd;
 struct ImDrawList;
+struct ImDrawData;
 struct ImFont;
 struct ImFontAtlas;
 struct ImGuiIO;
@@ -670,7 +671,7 @@ struct ImGuiIO
 
     // REQUIRED: rendering function. 
     // See example code if you are unsure of how to implement this.
-    void        (*RenderDrawListsFn)(ImDrawList** const draw_lists, int count);      
+    void        (*RenderDrawListsFn)(ImDrawData* data);      
 
     // Optional: access OS clipboard
     // (default to use native Win32 clipboard on Windows, otherwise uses a private clipboard. Override to access OS clipboard on other architectures)
@@ -981,7 +982,7 @@ struct ImGuiListClipper
 
 //-----------------------------------------------------------------------------
 // Draw List
-// Hold a series of drawing commands. The user provides a renderer for ImDrawList.
+// Hold a series of drawing commands. The user provides a renderer for ImDrawData which essentially contains an array of ImDrawList.
 //-----------------------------------------------------------------------------
 
 // Draw callbacks for advanced uses.
@@ -1087,6 +1088,15 @@ struct ImDrawList
     IMGUI_API void  UpdateTextureID();
 };
 
+// All draw data to render an ImGui frame
+struct ImDrawData
+{
+    ImDrawList**    cmd_lists;
+    int             cmd_lists_count;
+    int             total_vtx_count;        // For convenience, sum of all cmd_lists vtx_buffer.size()
+    int             total_idx_count;        // For convenience, sum of all cmd_lists idx_buffer.size()
+};
+
 // Load and rasterize multiple TTF fonts into a same texture.
 // Sharing a texture for multiple fonts allows us to reduce the number of draw calls during rendering.
 // We also add custom graphic data into the texture that serves for ImGui.