Examples: SDL+OpenGL3: Various fixes to example to make it matches current GL3 example (#356)

examples/sdl_opengl3_example/imgui_impl_sdl_gl3.cpp

@@ -1,11 +1,16 @@
 // ImGui SDL2 binding with OpenGL3
+// You can copy and use unmodified imgui_impl_* files in your project. 
+// If you use this binding you'll need to call 4 functions: ImGui_ImplXXXX_Init(), ImGui_ImplXXXX_NewFrame(), ImGui::Render() and ImGui_ImplXXXX_Shutdown().
+// See main.cpp for an example of using this.
 // https://github.com/ocornut/imgui
 
+#include "imgui.h"
+#include "imgui_impl_sdl_gl3.h"
+
+// SDL,GL3W
 #include <SDL.h>
 #include <SDL_syswm.h>
 #include <GL/gl3w.h>
-#include "imgui.h"
-#include "imgui_impl_sdl_gl3.h"
 
 // Data
 static SDL_Window*  g_Window = NULL;
@@ -33,6 +38,7 @@ void ImGui_ImplSdlGL3_RenderDrawLists(ImDrawData* draw_data)
 	GLint last_blend_dst; glGetIntegerv(GL_BLEND_DST, &last_blend_dst);
 	GLint last_blend_equation_rgb; glGetIntegerv(GL_BLEND_EQUATION_RGB, &last_blend_equation_rgb);
 	GLint last_blend_equation_alpha; glGetIntegerv(GL_BLEND_EQUATION_ALPHA, &last_blend_equation_alpha);
+    GLint last_viewport[4]; glGetIntegerv(GL_VIEWPORT, last_viewport);
 	GLboolean last_enable_blend = glIsEnabled(GL_BLEND);
 	GLboolean last_enable_cull_face = glIsEnabled(GL_CULL_FACE);
 	GLboolean last_enable_depth_test = glIsEnabled(GL_DEPTH_TEST);
@@ -53,12 +59,13 @@ void ImGui_ImplSdlGL3_RenderDrawLists(ImDrawData* draw_data)
 	draw_data->ScaleClipRects(io.DisplayFramebufferScale);
 
 	// Setup orthographic projection matrix
+    glViewport(0, 0, (GLsizei)io.DisplaySize.x, (GLsizei)io.DisplaySize.y);
 	const float ortho_projection[4][4] =
 	{
-		{ 2.0f / io.DisplaySize.x, 0.0f,                   0.0f, 0.0f },
-		{ 0.0f,                  2.0f / -io.DisplaySize.y, 0.0f, 0.0f },
+		{ 2.0f/io.DisplaySize.x, 0.0f,                   0.0f, 0.0f },
+		{ 0.0f,                  2.0f/-io.DisplaySize.y, 0.0f, 0.0f },
 		{ 0.0f,                  0.0f,                  -1.0f, 0.0f },
-		{ -1.0f,                  1.0f,                   0.0f, 1.0f },
+		{-1.0f,                  1.0f,                   0.0f, 1.0f },
 	};
 	glUseProgram(g_ShaderHandle);
 	glUniform1i(g_AttribLocationTex, 0);
@@ -86,7 +93,7 @@ void ImGui_ImplSdlGL3_RenderDrawLists(ImDrawData* draw_data)
 			{
 				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, GL_UNSIGNED_SHORT, idx_buffer_offset);
+				glDrawElements(GL_TRIANGLES, (GLsizei)pcmd->ElemCount, sizeof(ImDrawIdx) == 2 ? GL_UNSIGNED_SHORT : GL_UNSIGNED_INT, idx_buffer_offset);
 			}
 			idx_buffer_offset += pcmd->ElemCount;
 		}
@@ -104,6 +111,7 @@ void ImGui_ImplSdlGL3_RenderDrawLists(ImDrawData* draw_data)
 	if (last_enable_cull_face) glEnable(GL_CULL_FACE); else glDisable(GL_CULL_FACE);
 	if (last_enable_depth_test) glEnable(GL_DEPTH_TEST); else glDisable(GL_DEPTH_TEST);
 	if (last_enable_scissor_test) glEnable(GL_SCISSOR_TEST); else glDisable(GL_SCISSOR_TEST);
+    glViewport(last_viewport[0], last_viewport[1], (GLsizei)last_viewport[2], (GLsizei)last_viewport[3]);
 }
 
 static const char* ImGui_ImplSdlGL3_GetClipboardText()
@@ -165,7 +173,7 @@ void ImGui_ImplSdlGL3_CreateFontsTexture()
 	int width, height;
 	io.Fonts->GetTexDataAsRGBA32(&pixels, &width, &height);   // Load as RGBA 32-bits for OpenGL3 demo because it is more likely to be compatible with user's existing shader.
 
-															  // Create OpenGL texture
+	// Create OpenGL texture
 	glGenTextures(1, &g_FontTexture);
 	glBindTexture(GL_TEXTURE_2D, g_FontTexture);
 	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
@@ -259,12 +267,28 @@ bool ImGui_ImplSdlGL3_CreateDeviceObjects()
 
 void    ImGui_ImplSdlGL3_InvalidateDeviceObjects()
 {
-	if (g_FontTexture)
-	{
-		glDeleteTextures(1, &g_FontTexture);
-		ImGui::GetIO().Fonts->TexID = 0;
-		g_FontTexture = 0;
-	}
+    if (g_VaoHandle) glDeleteVertexArrays(1, &g_VaoHandle);
+    if (g_VboHandle) glDeleteBuffers(1, &g_VboHandle);
+    if (g_ElementsHandle) glDeleteBuffers(1, &g_ElementsHandle);
+    g_VaoHandle = g_VboHandle = g_ElementsHandle = 0;
+
+    glDetachShader(g_ShaderHandle, g_VertHandle);
+    glDeleteShader(g_VertHandle);
+    g_VertHandle = 0;
+
+    glDetachShader(g_ShaderHandle, g_FragHandle);
+    glDeleteShader(g_FragHandle);
+    g_FragHandle = 0;
+
+    glDeleteProgram(g_ShaderHandle);
+    g_ShaderHandle = 0;
+
+    if (g_FontTexture)
+    {
+        glDeleteTextures(1, &g_FontTexture);
+        ImGui::GetIO().Fonts->TexID = 0;
+        g_FontTexture = 0;
+    }
 }
 
 bool    ImGui_ImplSdlGL3_Init(SDL_Window *window)
@@ -308,32 +332,11 @@ bool    ImGui_ImplSdlGL3_Init(SDL_Window *window)
 
 void ImGui_ImplSdlGL3_Shutdown()
 {
-	if (g_VaoHandle) glDeleteVertexArrays(1, &g_VaoHandle);
-	if (g_VboHandle) glDeleteBuffers(1, &g_VboHandle);
-	if (g_ElementsHandle) glDeleteBuffers(1, &g_ElementsHandle);
-	g_VaoHandle = g_VboHandle = g_ElementsHandle = 0;
-
-	glDetachShader(g_ShaderHandle, g_VertHandle);
-	glDeleteShader(g_VertHandle);
-	g_VertHandle = 0;
-
-	glDetachShader(g_ShaderHandle, g_FragHandle);
-	glDeleteShader(g_FragHandle);
-	g_FragHandle = 0;
-
-	glDeleteProgram(g_ShaderHandle);
-	g_ShaderHandle = 0;
-
-	if (g_FontTexture)
-	{
-		glDeleteTextures(1, &g_FontTexture);
-		ImGui::GetIO().Fonts->TexID = 0;
-		g_FontTexture = 0;
-	}
+    ImGui_ImplSdlGL3_InvalidateDeviceObjects();
 	ImGui::Shutdown();
 }
 
-void ImGui_ImplSdlGL3_NewFrame(SDL_Window *window)
+void ImGui_ImplSdlGL3_NewFrame()
 {
 	if (!g_FontTexture)
 		ImGui_ImplSdlGL3_CreateDeviceObjects();
@@ -342,11 +345,9 @@ void ImGui_ImplSdlGL3_NewFrame(SDL_Window *window)
 
 	// Setup display size (every frame to accommodate for window resizing)
 	int w, h;
-	int display_w, display_h;
-	SDL_GetWindowSize(window, &w, &h);
-	SDL_GetWindowSize(window, &display_w, &display_h);
+	SDL_GetWindowSize(g_Window, &w, &h);
 	io.DisplaySize = ImVec2((float)w, (float)h);
-	io.DisplayFramebufferScale = ImVec2((float)display_w / w, (float)display_h / h);
+	io.DisplayFramebufferScale = ImVec2(1.0f, 1.0f);
 
 	// Setup time step
 	Uint32	time = SDL_GetTicks();
@@ -358,7 +359,7 @@ void ImGui_ImplSdlGL3_NewFrame(SDL_Window *window)
 	// (we already got mouse wheel, keyboard keys & characters from glfw callbacks polled in glfwPollEvents())
 	int mx, my;
 	Uint32 mouseMask = SDL_GetMouseState(&mx, &my);
-	if (SDL_GetWindowFlags(window) & SDL_WINDOW_MOUSE_FOCUS)
+	if (SDL_GetWindowFlags(g_Window) & SDL_WINDOW_MOUSE_FOCUS)
 		io.MousePos = ImVec2((float)mx, (float)my);   // Mouse position, in pixels (set to -1,-1 if no mouse / on another screen, etc.)
 	else
 		io.MousePos = ImVec2(-1, -1);
@@ -376,4 +377,4 @@ void ImGui_ImplSdlGL3_NewFrame(SDL_Window *window)
 
 	// Start the frame
 	ImGui::NewFrame();
-}
+}

examples/sdl_opengl3_example/imgui_impl_sdl_gl3.h

@@ -1,4 +1,7 @@
 // ImGui SDL2 binding with OpenGL3
+// You can copy and use unmodified imgui_impl_* files in your project. 
+// If you use this binding you'll need to call 4 functions: ImGui_ImplXXXX_Init(), ImGui_ImplXXXX_NewFrame(), ImGui::Render() and ImGui_ImplXXXX_Shutdown().
+// See main.cpp for an example of using this.
 // https://github.com/ocornut/imgui
 
 struct SDL_Window;
@@ -6,7 +9,7 @@ typedef union SDL_Event SDL_Event;
 
 IMGUI_API bool        ImGui_ImplSdlGL3_Init(SDL_Window *window);
 IMGUI_API void        ImGui_ImplSdlGL3_Shutdown();
-IMGUI_API void        ImGui_ImplSdlGL3_NewFrame(SDL_Window *window);
+IMGUI_API void        ImGui_ImplSdlGL3_NewFrame();
 IMGUI_API bool        ImGui_ImplSdlGL3_ProcessEvent(SDL_Event* event);
 
 // Use if you want to reset your rendering device without losing ImGui state.

examples/sdl_opengl3_example/main.cpp

@@ -61,7 +61,7 @@ int main(int, char**)
             if (event.type == SDL_QUIT)
                 done = true;
         }
-        ImGui_ImplSdlGL3_NewFrame(window);
+        ImGui_ImplSdlGL3_NewFrame();
 
         // 1. Show a simple window
         // Tip: if we don't call ImGui::Begin()/ImGui::End() the widgets appears in a window automatically called "Debug"