diff --git a/examples/opengl3_example/main.cpp b/examples/opengl3_example/main.cpp index e2f2442e..21e959ac 100644 --- a/examples/opengl3_example/main.cpp +++ b/examples/opengl3_example/main.cpp @@ -20,14 +20,9 @@ static ImVec2 mousePosScale(1.0f, 1.0f); // Shader variables static int shader_handle, vert_handle, frag_handle; - static int texture_location, ortho_location; static int position_location, uv_location, colour_location; -//streaming vbo -//we are going to use the same vertex buffer for all rendering of imgui -//so we need to use a large enough buffer as default. -//the buffer will be resized if needed in the rendering code, but it is not a "free" operation. -static size_t vbo_max_size = 1000000; +static size_t vbo_max_size = 20000; static unsigned int vbo_handle, vao_handle; // This is the main rendering function that you have to implement and provide to ImGui (via setting up 'RenderDrawListsFn' in the ImGuiIO structure) @@ -65,19 +60,19 @@ static void ImImpl_RenderDrawLists(ImDrawList** const cmd_lists, int cmd_lists_c glUniform1i(texture_location, 0); glUniformMatrix4fv(ortho_location, 1, GL_FALSE, &ortho_projection[0][0]); - // we will update the buffer in full, so we need to compute the total size of the buffer. + // 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, vbo_handle); size_t neededBufferSize = total_vtx_count * sizeof(ImDrawVert); if (neededBufferSize > vbo_max_size) { - vbo_max_size = neededBufferSize; - glBufferData(GL_ARRAY_BUFFER, total_vtx_count * sizeof(ImDrawVert), NULL, GL_STREAM_DRAW); + vbo_max_size = neededBufferSize + 5000; // Grow buffer + glBufferData(GL_ARRAY_BUFFER, neededBufferSize, NULL, GL_STREAM_DRAW); } + // Copy and convert all vertices into a single contiguous buffer unsigned char* buffer_data = (unsigned char*)glMapBuffer(GL_ARRAY_BUFFER, GL_WRITE_ONLY); if (!buffer_data) return; @@ -89,7 +84,6 @@ static void ImImpl_RenderDrawLists(ImDrawList** const cmd_lists, int cmd_lists_c } glUnmapBuffer(GL_ARRAY_BUFFER); glBindBuffer(GL_ARRAY_BUFFER, 0); - glBindVertexArray(vao_handle); int cmd_offset = 0; @@ -107,11 +101,11 @@ static void ImImpl_RenderDrawLists(ImDrawList** const cmd_lists, int cmd_lists_c cmd_offset = vtx_offset; } + // Restore modified state glBindVertexArray(0); glUseProgram(0); glDisable(GL_SCISSOR_TEST); glBindTexture(GL_TEXTURE_2D, 0); - } static const char* ImImpl_GetClipboardTextFn() @@ -159,7 +153,6 @@ static void glfw_char_callback(GLFWwindow* window, unsigned int c) ImGui::GetIO().AddInputCharacter((unsigned short)c); } - // OpenGL code based on http://open.gl tutorials void InitGL() { @@ -183,35 +176,33 @@ void InitGL() GLenum err = glewInit(); if (GLEW_OK != err) - { fprintf(stderr, "Error: %s\n", glewGetErrorString(err)); - } - const GLchar *vertex_shader = \ - "#version 330\n" - "uniform mat4 ortho;\n" - "in vec2 Position;\n" - "in vec2 UV;\n" - "in vec4 Colour;\n" - "out vec2 Frag_UV;\n" - "out vec4 Frag_Colour;\n" - "void main()\n" - "{\n" - " Frag_UV = UV;\n" - " Frag_Colour = Colour;\n" - " gl_Position = ortho*vec4(Position.xy,0,1);\n" - "}\n"; + const GLchar *vertex_shader = + "#version 330\n" + "uniform mat4 ortho;\n" + "in vec2 Position;\n" + "in vec2 UV;\n" + "in vec4 Colour;\n" + "out vec2 Frag_UV;\n" + "out vec4 Frag_Colour;\n" + "void main()\n" + "{\n" + " Frag_UV = UV;\n" + " Frag_Colour = Colour;\n" + " gl_Position = ortho*vec4(Position.xy,0,1);\n" + "}\n"; - const GLchar* fragment_shader = \ - "#version 330\n" - "uniform sampler2D Texture;\n" - "in vec2 Frag_UV;\n" - "in vec4 Frag_Colour;\n" - "out vec4 FragColor;\n" - "void main()\n" - "{\n" - " FragColor = Frag_Colour * texture( Texture, Frag_UV.st);\n" - "}\n"; + const GLchar* fragment_shader = + "#version 330\n" + "uniform sampler2D Texture;\n" + "in vec2 Frag_UV;\n" + "in vec4 Frag_Colour;\n" + "out vec4 FragColor;\n" + "void main()\n" + "{\n" + " FragColor = Frag_Colour * texture( Texture, Frag_UV.st);\n" + "}\n"; shader_handle = glCreateProgram(); vert_handle = glCreateShader(GL_VERTEX_SHADER); @@ -246,20 +237,22 @@ void InitGL() glVertexAttribPointer(colour_location, 4, GL_UNSIGNED_BYTE, GL_TRUE, sizeof(ImDrawVert), (GLvoid*) offsetof(ImDrawVert, col)); glBindVertexArray(0); glBindBuffer(GL_ARRAY_BUFFER, 0); - - } void InitImGui() { - int w, h; - glfwGetWindowSize(window, &w, &h); + int w, h; + int display_w, display_h; + glfwGetWindowSize(window, &w, &h); + glfwGetFramebufferSize(window, &display_w, &display_h); + mousePosScale.x = (float)display_w / w; // Some screens e.g. Retina display have framebuffer size != from window size, and mouse inputs are given in window/screen coordinates. + mousePosScale.y = (float)display_h / h; ImGuiIO& io = ImGui::GetIO(); - io.DisplaySize = ImVec2((float)w, (float)h); // Display size, in pixels. For clamping windows positions. - io.DeltaTime = 1.0f / 60.0f; // Time elapsed since last frame, in seconds (in this sample app we'll override this every frame because our timestep is variable) - io.PixelCenterOffset = 0.5f; // Align OpenGL texels - io.KeyMap[ImGuiKey_Tab] = GLFW_KEY_TAB; // Keyboard mapping. ImGui will use those indices to peek into the io.KeyDown[] array. + io.DisplaySize = ImVec2((float)display_w, (float)display_h); // Display size, in pixels. For clamping windows positions. + io.DeltaTime = 1.0f / 60.0f; // Time elapsed since last frame, in seconds (in this sample app we'll override this every frame because our timestep is variable) + io.PixelCenterOffset = 0.5f; // Align OpenGL texels + io.KeyMap[ImGuiKey_Tab] = GLFW_KEY_TAB; // Keyboard mapping. ImGui will use those indices to peek into the io.KeyDown[] array. io.KeyMap[ImGuiKey_LeftArrow] = GLFW_KEY_LEFT; io.KeyMap[ImGuiKey_RightArrow] = GLFW_KEY_RIGHT; io.KeyMap[ImGuiKey_UpArrow] = GLFW_KEY_UP; @@ -309,9 +302,9 @@ void UpdateImGui() // (we already got mouse wheel, keyboard keys & characters from glfw callbacks polled in glfwPollEvents()) double mouse_x, mouse_y; glfwGetCursorPos(window, &mouse_x, &mouse_y); - io.MousePos = ImVec2((float)mouse_x, (float)mouse_y); // Mouse position, in pixels (set to -1,-1 if no mouse / on another screen, etc.) - io.MouseDown[0] = glfwGetMouseButton(window, GLFW_MOUSE_BUTTON_LEFT) != 0; - io.MouseDown[1] = glfwGetMouseButton(window, GLFW_MOUSE_BUTTON_RIGHT) != 0; + io.MousePos = ImVec2((float)mouse_x * mousePosScale.x, (float)mouse_y * mousePosScale.y); // Mouse position, in pixels (set to -1,-1 if no mouse / on another screen, etc.) + io.MouseDown[0] = mousePressed[0] || glfwGetMouseButton(window, GLFW_MOUSE_BUTTON_LEFT) != 0; // If a mouse press event came, always pass it as "mouse held this frame", so we don't miss click-release events that are shorter than 1 frame. + io.MouseDown[1] = mousePressed[1] || glfwGetMouseButton(window, GLFW_MOUSE_BUTTON_RIGHT) != 0; // Start the frame ImGui::NewFrame(); @@ -330,50 +323,54 @@ int main(int argc, char** argv) glfwPollEvents(); UpdateImGui(); - // Create a simple window - // Tip: if we don't call ImGui::Begin()/ImGui::End() the widgets appears in a window automatically called "Debug" - static bool show_test_window = true; - static bool show_another_window = false; - static float f; - ImGui::Text("Hello, world!"); - ImGui::SliderFloat("float", &f, 0.0f, 1.0f); - show_test_window ^= ImGui::Button("Test Window"); - show_another_window ^= ImGui::Button("Another Window"); + static bool show_test_window = true; + static bool show_another_window = false; - // Calculate and show framerate - static float ms_per_frame[120] = { 0 }; - static int ms_per_frame_idx = 0; - static float ms_per_frame_accum = 0.0f; - ms_per_frame_accum -= ms_per_frame[ms_per_frame_idx]; - ms_per_frame[ms_per_frame_idx] = ImGui::GetIO().DeltaTime * 1000.0f; - ms_per_frame_accum += ms_per_frame[ms_per_frame_idx]; - ms_per_frame_idx = (ms_per_frame_idx + 1) % 120; - const float ms_per_frame_avg = ms_per_frame_accum / 120; - ImGui::Text("Application average %.3f ms/frame (%.1f FPS)", ms_per_frame_avg, 1000.0f / ms_per_frame_avg); + // 1. Show a simple window + // Tip: if we don't call ImGui::Begin()/ImGui::End() the widgets appears in a window automatically called "Debug" + { + static float f; + ImGui::Text("Hello, world!"); + ImGui::SliderFloat("float", &f, 0.0f, 1.0f); + show_test_window ^= ImGui::Button("Test Window"); + show_another_window ^= ImGui::Button("Another Window"); - // Show the ImGui test window - // Most of user example code is in ImGui::ShowTestWindow() - if (show_test_window) - { - ImGui::SetNewWindowDefaultPos(ImVec2(650, 20)); // Normally user code doesn't need/want to call it because positions are saved in .ini file anyway. Here we just want to make the demo initial state a bit more friendly! - ImGui::ShowTestWindow(&show_test_window); - } + // Calculate and show frame rate + static float ms_per_frame[120] = { 0 }; + static int ms_per_frame_idx = 0; + static float ms_per_frame_accum = 0.0f; + ms_per_frame_accum -= ms_per_frame[ms_per_frame_idx]; + ms_per_frame[ms_per_frame_idx] = ImGui::GetIO().DeltaTime * 1000.0f; + ms_per_frame_accum += ms_per_frame[ms_per_frame_idx]; + ms_per_frame_idx = (ms_per_frame_idx + 1) % 120; + const float ms_per_frame_avg = ms_per_frame_accum / 120; + ImGui::Text("Application average %.3f ms/frame (%.1f FPS)", ms_per_frame_avg, 1000.0f / ms_per_frame_avg); + } - // Show another simple window - if (show_another_window) - { - ImGui::Begin("Another Window", &show_another_window, ImVec2(200,100)); - ImGui::Text("Hello"); - ImGui::End(); - } + // 2. Show another simple window, this time using an explicit Begin/End pair + if (show_another_window) + { + ImGui::Begin("Another Window", &show_another_window, ImVec2(200,100)); + ImGui::Text("Hello"); + ImGui::End(); + } - // Rendering + // 3. Show the ImGui test window. Most of the sample code is in ImGui::ShowTestWindow() + if (show_test_window) + { + ImGui::SetNewWindowDefaultPos(ImVec2(650, 20)); // Normally user code doesn't need/want to call this, because positions are saved in .ini file. Here we just want to make the demo initial state a bit more friendly! + ImGui::ShowTestWindow(&show_test_window); + } + + // Rendering glViewport(0, 0, (int)io.DisplaySize.x, (int)io.DisplaySize.y); glClearColor(0.8f, 0.6f, 0.6f, 1.0f); glClear(GL_COLOR_BUFFER_BIT); ImGui::Render(); glfwSwapBuffers(window); } + + // Cleanup if (vao_handle) glDeleteVertexArrays(1, &vao_handle); if (vbo_handle) glDeleteBuffers(1, &vbo_handle); glDetachShader(shader_handle, vert_handle); diff --git a/examples/opengl_example/main.cpp b/examples/opengl_example/main.cpp index 32ca0b9f..6247f893 100644 --- a/examples/opengl_example/main.cpp +++ b/examples/opengl_example/main.cpp @@ -305,7 +305,9 @@ int main(int argc, char** argv) glfwSwapBuffers(window); } + // Cleanup ImGui::Shutdown(); glfwTerminate(); - return 0; + + return 0; }