Examples: DirectX10, DirectX11, OpenGL2, OpenGL3: Added support for io.DisplayPos.

examples/imgui_impl_dx10.cpp

@@ -10,6 +10,7 @@
 
 // CHANGELOG 
 // (minor and older changes stripped away, please see git history for details)
+//  2018-XX-XX: Draw: Offset projection matrix and clipping rectangle by io.DisplayPos (which will be non-zero for multi-viewport applications).
 //  2018-02-16: Misc: Obsoleted the io.RenderDrawListsFn callback and exposed ImGui_ImplDX10_RenderDrawData() in the .h file so you can call it yourself.
 //  2018-02-06: Misc: Removed call to ImGui::Shutdown() which is not available from 1.60 WIP, user needs to call CreateContext/DestroyContext themselves.
 //  2018-02-06: Inputs: Added mapping for ImGuiKey_Space.
@@ -105,15 +106,17 @@ void ImGui_ImplDX10_RenderDrawData(ImDrawData* draw_data)
     g_pIB->Unmap();
 
     // Setup orthographic projection matrix into our constant buffer
+    // Our visible imgui space lies from io.DisplayPos (top left) to io.DisplayPos+io.DisplaySize (bottom right). io.DisplayPos is typically (0,0) for single viewport applications.
+    ImGuiIO& io = ImGui::GetIO();
     {
         void* mapped_resource;
         if (g_pVertexConstantBuffer->Map(D3D10_MAP_WRITE_DISCARD, 0, &mapped_resource) != S_OK)
             return;
         VERTEX_CONSTANT_BUFFER* constant_buffer = (VERTEX_CONSTANT_BUFFER*)mapped_resource;
-        float L = 0.0f;
+        float L = io.DisplayPos.x;
-        float R = ImGui::GetIO().DisplaySize.x;
+        float R = io.DisplayPos.x + io.DisplaySize.x;
-        float B = ImGui::GetIO().DisplaySize.y;
+        float T = io.DisplayPos.y;
-        float T = 0.0f;
+        float B = io.DisplayPos.y + io.DisplaySize.y;
         float mvp[4][4] =
         {
             { 2.0f/(R-L),   0.0f,           0.0f,       0.0f },
@@ -167,8 +170,8 @@ void ImGui_ImplDX10_RenderDrawData(ImDrawData* draw_data)
     // Setup viewport
     D3D10_VIEWPORT vp;
     memset(&vp, 0, sizeof(D3D10_VIEWPORT));
-    vp.Width = (UINT)ImGui::GetIO().DisplaySize.x;
+    vp.Width = (UINT)io.DisplaySize.x;
-    vp.Height = (UINT)ImGui::GetIO().DisplaySize.y;
+    vp.Height = (UINT)io.DisplaySize.y;
     vp.MinDepth = 0.0f;
     vp.MaxDepth = 1.0f;
     vp.TopLeftX = vp.TopLeftY = 0;
@@ -203,13 +206,18 @@ void ImGui_ImplDX10_RenderDrawData(ImDrawData* draw_data)
             const ImDrawCmd* pcmd = &cmd_list->CmdBuffer[cmd_i];
             if (pcmd->UserCallback)
             {
+                // User callback (registered via ImDrawList::AddCallback)
                 pcmd->UserCallback(cmd_list, pcmd);
             }
             else
             {
-                const D3D10_RECT r = { (LONG)pcmd->ClipRect.x, (LONG)pcmd->ClipRect.y, (LONG)pcmd->ClipRect.z, (LONG)pcmd->ClipRect.w };
+                // Apply scissor/clipping rectangle
+                const ImVec4 clip_rect = ImVec4(pcmd->ClipRect.x - io.DisplayPos.x, pcmd->ClipRect.y - io.DisplayPos.y, pcmd->ClipRect.z - io.DisplayPos.x, pcmd->ClipRect.w - io.DisplayPos.y);
+                const D3D10_RECT clip_rect_dx = { (LONG)clip_rect.x, (LONG)clip_rect.y, (LONG)clip_rect.z, (LONG)clip_rect.w };
+                ctx->RSSetScissorRects(1, &clip_rect_dx);
+
+                // Bind texture, Draw
                 ctx->PSSetShaderResources(0, 1, (ID3D10ShaderResourceView**)&pcmd->TextureId);
-                ctx->RSSetScissorRects(1, &r);
                 ctx->DrawIndexed(pcmd->ElemCount, idx_offset, vtx_offset);
             }
             idx_offset += pcmd->ElemCount;

examples/imgui_impl_dx11.cpp

@@ -10,6 +10,7 @@
 
 // CHANGELOG
 // (minor and older changes stripped away, please see git history for details)
+//  2018-XX-XX: Draw: Offset projection matrix and clipping rectangle by io.DisplayPos (which will be non-zero for multi-viewport applications).
 //  2018-02-16: Misc: Obsoleted the io.RenderDrawListsFn callback and exposed ImGui_ImplDX11_RenderDrawData() in the .h file so you can call it yourself.
 //  2018-02-06: Misc: Removed call to ImGui::Shutdown() which is not available from 1.60 WIP, user needs to call CreateContext/DestroyContext themselves.
 //  2018-02-06: Inputs: Added mapping for ImGuiKey_Space.
@@ -107,15 +108,17 @@ void ImGui_ImplDX11_RenderDrawData(ImDrawData* draw_data)
     ctx->Unmap(g_pIB, 0);
 
     // Setup orthographic projection matrix into our constant buffer
+    // Our visible imgui space lies from io.DisplayPos (top left) to io.DisplayPos+io.DisplaySize (bottom right). io.DisplayPos is typically (0,0) for single viewport applications.
+    ImGuiIO& io = ImGui::GetIO();
     {
         D3D11_MAPPED_SUBRESOURCE mapped_resource;
         if (ctx->Map(g_pVertexConstantBuffer, 0, D3D11_MAP_WRITE_DISCARD, 0, &mapped_resource) != S_OK)
             return;
         VERTEX_CONSTANT_BUFFER* constant_buffer = (VERTEX_CONSTANT_BUFFER*)mapped_resource.pData;
-        float L = 0.0f;
+        float L = io.DisplayPos.x;
-        float R = ImGui::GetIO().DisplaySize.x;
+        float R = io.DisplayPos.x + io.DisplaySize.x;
-        float B = ImGui::GetIO().DisplaySize.y;
+        float T = io.DisplayPos.y;
-        float T = 0.0f;
+        float B = io.DisplayPos.y + io.DisplaySize.y;
         float mvp[4][4] =
         {
             { 2.0f/(R-L),   0.0f,           0.0f,       0.0f },
@@ -172,8 +175,8 @@ void ImGui_ImplDX11_RenderDrawData(ImDrawData* draw_data)
     // Setup viewport
     D3D11_VIEWPORT vp;
     memset(&vp, 0, sizeof(D3D11_VIEWPORT));
-    vp.Width = ImGui::GetIO().DisplaySize.x;
+    vp.Width =  io.DisplaySize.x;
-    vp.Height = ImGui::GetIO().DisplaySize.y;
+    vp.Height = io.DisplaySize.y;
     vp.MinDepth = 0.0f;
     vp.MaxDepth = 1.0f;
     vp.TopLeftX = vp.TopLeftY = 0;
@@ -208,13 +211,18 @@ void ImGui_ImplDX11_RenderDrawData(ImDrawData* draw_data)
             const ImDrawCmd* pcmd = &cmd_list->CmdBuffer[cmd_i];
             if (pcmd->UserCallback)
             {
+                // User callback (registered via ImDrawList::AddCallback)
                 pcmd->UserCallback(cmd_list, pcmd);
             }
             else
             {
-                const D3D11_RECT r = { (LONG)pcmd->ClipRect.x, (LONG)pcmd->ClipRect.y, (LONG)pcmd->ClipRect.z, (LONG)pcmd->ClipRect.w };
+                // Apply scissor/clipping rectangle
+                const ImVec4 clip_rect = ImVec4(pcmd->ClipRect.x - io.DisplayPos.x, pcmd->ClipRect.y - io.DisplayPos.y, pcmd->ClipRect.z - io.DisplayPos.x, pcmd->ClipRect.w - io.DisplayPos.y);
+                const D3D11_RECT clip_rect_dx = { (LONG)clip_rect.x, (LONG)clip_rect.y, (LONG)clip_rect.z, (LONG)clip_rect.w };
+                ctx->RSSetScissorRects(1, &clip_rect_dx);
+
+                // Bind texture, Draw
                 ctx->PSSetShaderResources(0, 1, (ID3D11ShaderResourceView**)&pcmd->TextureId);
-                ctx->RSSetScissorRects(1, &r);
                 ctx->DrawIndexed(pcmd->ElemCount, idx_offset, vtx_offset);
             }
             idx_offset += pcmd->ElemCount;

examples/imgui_impl_opengl2.cpp

@@ -6,6 +6,10 @@
 // confuse your GPU driver. 
 // The GL2 code is unable to reset attributes or even call e.g. "glUseProgram(0)" because they don't exist in that API.
 
+// CHANGELOG 
+// (minor and older changes stripped away, please see git history for details)
+//  2018-XX-XX: Draw: Offset projection matrix and clipping rectangle by io.DisplayPos (which will be non-zero for multi-viewport applications).
+
 #include "imgui.h"
 #include "imgui_impl_opengl2.h"
 
@@ -75,11 +79,12 @@ void ImGui_ImplOpenGL2_RenderDrawData(ImDrawData* draw_data)
     //glUseProgram(0); // You may want this if using this code in an OpenGL 3+ context where shaders may be bound
 
     // Setup viewport, orthographic projection matrix
+    // Our visible imgui space lies from io.DisplayPos (top left) to io.DisplayPos+io.DisplaySize (bottom right). io.DisplayPos is typically (0,0) for single viewport applications.
     glViewport(0, 0, (GLsizei)fb_width, (GLsizei)fb_height);
     glMatrixMode(GL_PROJECTION);
     glPushMatrix();
     glLoadIdentity();
-    glOrtho(0.0f, io.DisplaySize.x, io.DisplaySize.y, 0.0f, -1.0f, +1.0f);
+    glOrtho(io.DisplayPos.x, io.DisplayPos.x + io.DisplaySize.x, io.DisplayPos.y + io.DisplaySize.y, io.DisplayPos.y, -1.0f, +1.0f);
     glMatrixMode(GL_MODELVIEW);
     glPushMatrix();
     glLoadIdentity();
@@ -99,14 +104,22 @@ void ImGui_ImplOpenGL2_RenderDrawData(ImDrawData* draw_data)
             const ImDrawCmd* pcmd = &cmd_list->CmdBuffer[cmd_i];
             if (pcmd->UserCallback)
             {
+                // User callback (registered via ImDrawList::AddCallback)
                 pcmd->UserCallback(cmd_list, pcmd);
             }
             else
             {
+                ImVec4 clip_rect = ImVec4(pcmd->ClipRect.x - io.DisplayPos.x, pcmd->ClipRect.y - io.DisplayPos.y, pcmd->ClipRect.z - io.DisplayPos.x, pcmd->ClipRect.w - io.DisplayPos.y);
+                if (clip_rect.x < fb_width && clip_rect.y < fb_height && clip_rect.z >= 0.0f && clip_rect.w >= 0.0f)
+                {
+                    // Apply scissor/clipping rectangle
+                    glScissor((int)clip_rect.x, (int)(fb_height - clip_rect.w), (int)(clip_rect.z - clip_rect.x), (int)(clip_rect.w - clip_rect.y));
+
+                    // Bind texture, Draw
                     glBindTexture(GL_TEXTURE_2D, (GLuint)(intptr_t)pcmd->TextureId);
-                glScissor((int)pcmd->ClipRect.x, (int)(fb_height - pcmd->ClipRect.w), (int)(pcmd->ClipRect.z - pcmd->ClipRect.x), (int)(pcmd->ClipRect.w - pcmd->ClipRect.y));
                     glDrawElements(GL_TRIANGLES, (GLsizei)pcmd->ElemCount, sizeof(ImDrawIdx) == 2 ? GL_UNSIGNED_SHORT : GL_UNSIGNED_INT, idx_buffer);
                 }
+            }
             idx_buffer += pcmd->ElemCount;
         }
     }

examples/imgui_impl_opengl3.cpp

@@ -1,3 +1,7 @@
+// CHANGELOG 
+// (minor and older changes stripped away, please see git history for details)
+//  2018-XX-XX: Draw: Offset projection matrix and clipping rectangle by io.DisplayPos (which will be non-zero for multi-viewport applications).
+
 #include "imgui.h"
 #include "imgui_impl_opengl3.h"
 #include <GL/gl3w.h>  // This example is using gl3w to access OpenGL functions (because it is small). You may use glew/glad/glLoadGen/etc. whatever already works for you.
@@ -72,13 +76,18 @@ void    ImGui_ImplOpenGL3_RenderDrawData(ImDrawData* draw_data)
     glPolygonMode(GL_FRONT_AND_BACK, GL_FILL);
 
     // Setup viewport, orthographic projection matrix
+    // Our visible imgui space lies from io.DisplayPos (top left) to io.DisplayPos+io.DisplaySize (bottom right). io.DisplayPos is typically (0,0) for single viewport applications.
     glViewport(0, 0, (GLsizei)fb_width, (GLsizei)fb_height);
+    float L = io.DisplayPos.x;
+    float R = io.DisplayPos.x + io.DisplaySize.x;
+    float T = io.DisplayPos.y;
+    float B = io.DisplayPos.y + io.DisplaySize.y;
     const float ortho_projection[4][4] =
     {
-        { 2.0f/io.DisplaySize.x, 0.0f,                   0.0f, 0.0f },
+        { 2.0f/(R-L),   0.0f,         0.0f,   0.0f },
-        { 0.0f,                  2.0f/-io.DisplaySize.y, 0.0f, 0.0f },
+        { 0.0f,         2.0f/(T-B),   0.0f,   0.0f },
         { 0.0f,         0.0f,        -1.0f,   0.0f },
-        { -1.0f,                 1.0f,                   0.0f, 1.0f },
+        { (R+L)/(L-R),  (T+B)/(B-T),  0.0f,   1.0f },
     };
     glUseProgram(g_ShaderHandle);
     glUniform1i(g_AttribLocationTex, 0);
@@ -102,14 +111,22 @@ void    ImGui_ImplOpenGL3_RenderDrawData(ImDrawData* draw_data)
             const ImDrawCmd* pcmd = &cmd_list->CmdBuffer[cmd_i];
             if (pcmd->UserCallback)
             {
+                // User callback (registered via ImDrawList::AddCallback)
                 pcmd->UserCallback(cmd_list, pcmd);
             }
             else
             {
+                ImVec4 clip_rect = ImVec4(pcmd->ClipRect.x - io.DisplayPos.x, pcmd->ClipRect.y - io.DisplayPos.y, pcmd->ClipRect.z - io.DisplayPos.x, pcmd->ClipRect.w - io.DisplayPos.y);
+                if (clip_rect.x < fb_width && clip_rect.y < fb_height && clip_rect.z >= 0.0f && clip_rect.w >= 0.0f)
+                {
+                    // Apply scissor/clipping rectangle
+                    glScissor((int)clip_rect.x, (int)(fb_height - clip_rect.w), (int)(clip_rect.z - clip_rect.x), (int)(clip_rect.w - clip_rect.y));
+
+                    // Bind texture, Draw
                     glBindTexture(GL_TEXTURE_2D, (GLuint)(intptr_t)pcmd->TextureId);
-                glScissor((int)pcmd->ClipRect.x, (int)(fb_height - pcmd->ClipRect.w), (int)(pcmd->ClipRect.z - pcmd->ClipRect.x), (int)(pcmd->ClipRect.w - pcmd->ClipRect.y));
                     glDrawElements(GL_TRIANGLES, (GLsizei)pcmd->ElemCount, sizeof(ImDrawIdx) == 2 ? GL_UNSIGNED_SHORT : GL_UNSIGNED_INT, idx_buffer_offset);
                 }
+            }
             idx_buffer_offset += pcmd->ElemCount;
         }
     }