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344 lines
13 KiB
344 lines
13 KiB
// ImGui GLFW binding with OpenGL3 + shaders |
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// https://github.com/ocornut/imgui |
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#include <imgui.h> |
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#include "imgui_impl_glfw_gl3.h" |
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// GL3W/GLFW |
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#include <GL/gl3w.h> |
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#include <GLFW/glfw3.h> |
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#ifdef _MSC_VER |
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#undef APIENTRY |
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#define GLFW_EXPOSE_NATIVE_WIN32 |
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#define GLFW_EXPOSE_NATIVE_WGL |
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#include <GLFW/glfw3native.h> |
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#endif |
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static GLFWwindow* g_window = NULL; |
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static bool g_mouse_pressed[3] = { false, false, false }; |
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static float g_mouse_wheel = 0.0f; |
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static double g_time = 0.0f; |
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static bool g_font_texture_loaded = false; |
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// Handles for OpenGL3 rendering |
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static int g_shader_handle = 0, g_vert_handle = 0, g_frag_handle = 0; |
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static int g_texture_location = 0, g_proj_mtx_location = 0; |
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static int g_position_location = 0, g_uv_location = 0, g_colour_location = 0; |
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static size_t g_vbo_max_size = 20000; |
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static unsigned int g_vbo_handle = 0, g_vao_handle = 0; |
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// This is the main rendering function that you have to implement and provide to ImGui (via setting up 'RenderDrawListsFn' in the ImGuiIO structure) |
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// If text or lines are blurry when integrating ImGui in your engine: |
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// - in your Render function, try translating your projection matrix by (0.5f,0.5f) or (0.375f,0.375f) |
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static void ImGui_ImplGlfwGL3_RenderDrawLists(ImDrawList** const cmd_lists, int cmd_lists_count) |
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{ |
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if (cmd_lists_count == 0) |
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return; |
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// Setup render state: alpha-blending enabled, no face culling, no depth testing, scissor enabled |
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glEnable(GL_BLEND); |
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glBlendEquation(GL_FUNC_ADD); |
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glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA); |
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glDisable(GL_CULL_FACE); |
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glDisable(GL_DEPTH_TEST); |
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glEnable(GL_SCISSOR_TEST); |
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glActiveTexture(GL_TEXTURE0); |
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// Setup orthographic projection matrix |
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const float width = ImGui::GetIO().DisplaySize.x; |
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const float height = ImGui::GetIO().DisplaySize.y; |
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const float ortho_projection[4][4] = |
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{ |
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{ 2.0f/width, 0.0f, 0.0f, 0.0f }, |
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{ 0.0f, 2.0f/-height, 0.0f, 0.0f }, |
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{ 0.0f, 0.0f, -1.0f, 0.0f }, |
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{ -1.0f, 1.0f, 0.0f, 1.0f }, |
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}; |
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glUseProgram(g_shader_handle); |
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glUniform1i(g_texture_location, 0); |
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glUniformMatrix4fv(g_proj_mtx_location, 1, GL_FALSE, &ortho_projection[0][0]); |
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// Grow our buffer according to what we need |
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size_t total_vtx_count = 0; |
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for (int n = 0; n < cmd_lists_count; n++) |
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total_vtx_count += cmd_lists[n]->vtx_buffer.size(); |
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glBindBuffer(GL_ARRAY_BUFFER, g_vbo_handle); |
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size_t neededBufferSize = total_vtx_count * sizeof(ImDrawVert); |
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if (neededBufferSize > g_vbo_max_size) |
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{ |
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g_vbo_max_size = neededBufferSize + 5000; // Grow buffer |
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glBufferData(GL_ARRAY_BUFFER, g_vbo_max_size, NULL, GL_STREAM_DRAW); |
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} |
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// Copy and convert all vertices into a single contiguous buffer |
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unsigned char* buffer_data = (unsigned char*)glMapBuffer(GL_ARRAY_BUFFER, GL_WRITE_ONLY); |
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if (!buffer_data) |
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return; |
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for (int n = 0; n < cmd_lists_count; n++) |
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{ |
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const ImDrawList* cmd_list = cmd_lists[n]; |
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memcpy(buffer_data, &cmd_list->vtx_buffer[0], cmd_list->vtx_buffer.size() * sizeof(ImDrawVert)); |
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buffer_data += cmd_list->vtx_buffer.size() * sizeof(ImDrawVert); |
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} |
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glUnmapBuffer(GL_ARRAY_BUFFER); |
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glBindBuffer(GL_ARRAY_BUFFER, 0); |
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glBindVertexArray(g_vao_handle); |
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int cmd_offset = 0; |
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for (int n = 0; n < cmd_lists_count; n++) |
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{ |
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const ImDrawList* cmd_list = cmd_lists[n]; |
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int vtx_offset = cmd_offset; |
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const ImDrawCmd* pcmd_end = cmd_list->commands.end(); |
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for (const ImDrawCmd* pcmd = cmd_list->commands.begin(); pcmd != pcmd_end; pcmd++) |
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{ |
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glBindTexture(GL_TEXTURE_2D, (GLuint)(intptr_t)pcmd->texture_id); |
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glScissor((int)pcmd->clip_rect.x, (int)(height - pcmd->clip_rect.w), (int)(pcmd->clip_rect.z - pcmd->clip_rect.x), (int)(pcmd->clip_rect.w - pcmd->clip_rect.y)); |
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glDrawArrays(GL_TRIANGLES, vtx_offset, pcmd->vtx_count); |
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vtx_offset += pcmd->vtx_count; |
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} |
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cmd_offset = vtx_offset; |
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} |
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// Restore modified state |
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glBindVertexArray(0); |
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glUseProgram(0); |
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glDisable(GL_SCISSOR_TEST); |
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glBindTexture(GL_TEXTURE_2D, 0); |
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} |
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static const char* ImGui_ImplGlfwGL3_GetClipboardText() |
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{ |
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return glfwGetClipboardString(g_window); |
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} |
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static void ImGui_ImplGlfwGL3_SetClipboardText(const char* text) |
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{ |
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glfwSetClipboardString(g_window, text); |
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} |
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void ImGui_ImplGlfwGL3_MouseButtonCallback(GLFWwindow* window, int button, int action, int mods) |
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{ |
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if (action == GLFW_PRESS && button >= 0 && button < 3) |
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g_mouse_pressed[button] = true; |
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} |
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void ImGui_ImplGlfwGL3_ScrollCallback(GLFWwindow* window, double xoffset, double yoffset) |
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{ |
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g_mouse_wheel += (float)yoffset; // Use fractional mouse wheel, 1.0 unit 5 lines. |
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} |
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void ImGui_ImplGlfwGL3_KeyCallback(GLFWwindow* window, int key, int scancode, int action, int mods) |
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{ |
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ImGuiIO& io = ImGui::GetIO(); |
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if (action == GLFW_PRESS) |
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io.KeysDown[key] = true; |
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if (action == GLFW_RELEASE) |
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io.KeysDown[key] = false; |
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io.KeyCtrl = (mods & GLFW_MOD_CONTROL) != 0; |
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io.KeyShift = (mods & GLFW_MOD_SHIFT) != 0; |
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} |
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void ImGui_ImplGlfwGL3_CharCallback(GLFWwindow* window, unsigned int c) |
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{ |
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ImGuiIO& io = ImGui::GetIO(); |
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if (c > 0 && c < 0x10000) |
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io.AddInputCharacter((unsigned short)c); |
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} |
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void ImGui_ImplGlfwGL3_LoadFontsTexture() |
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{ |
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ImGuiIO& io = ImGui::GetIO(); |
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unsigned char* pixels; |
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int width, height; |
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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. |
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GLuint tex_id; |
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glGenTextures(1, &tex_id); |
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glBindTexture(GL_TEXTURE_2D, tex_id); |
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glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR); |
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glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR); |
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glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, pixels); |
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// Store our identifier |
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io.Fonts->TexID = (void *)(intptr_t)tex_id; |
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g_font_texture_loaded = true; |
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} |
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static void InitGL() |
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{ |
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const GLchar *vertex_shader = |
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"#version 330\n" |
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"uniform mat4 ProjMtx;\n" |
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"in vec2 Position;\n" |
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"in vec2 UV;\n" |
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"in vec4 Color;\n" |
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"out vec2 Frag_UV;\n" |
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"out vec4 Frag_Color;\n" |
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"void main()\n" |
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"{\n" |
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" Frag_UV = UV;\n" |
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" Frag_Color = Color;\n" |
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" gl_Position = ProjMtx * vec4(Position.xy,0,1);\n" |
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"}\n"; |
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const GLchar* fragment_shader = |
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"#version 330\n" |
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"uniform sampler2D Texture;\n" |
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"in vec2 Frag_UV;\n" |
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"in vec4 Frag_Color;\n" |
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"out vec4 Out_Color;\n" |
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"void main()\n" |
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"{\n" |
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" Out_Color = Frag_Color * texture( Texture, Frag_UV.st);\n" |
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"}\n"; |
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g_shader_handle = glCreateProgram(); |
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g_vert_handle = glCreateShader(GL_VERTEX_SHADER); |
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g_frag_handle = glCreateShader(GL_FRAGMENT_SHADER); |
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glShaderSource(g_vert_handle, 1, &vertex_shader, 0); |
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glShaderSource(g_frag_handle, 1, &fragment_shader, 0); |
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glCompileShader(g_vert_handle); |
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glCompileShader(g_frag_handle); |
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glAttachShader(g_shader_handle, g_vert_handle); |
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glAttachShader(g_shader_handle, g_frag_handle); |
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glLinkProgram(g_shader_handle); |
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g_texture_location = glGetUniformLocation(g_shader_handle, "Texture"); |
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g_proj_mtx_location = glGetUniformLocation(g_shader_handle, "ProjMtx"); |
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g_position_location = glGetAttribLocation(g_shader_handle, "Position"); |
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g_uv_location = glGetAttribLocation(g_shader_handle, "UV"); |
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g_colour_location = glGetAttribLocation(g_shader_handle, "Color"); |
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glGenBuffers(1, &g_vbo_handle); |
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glBindBuffer(GL_ARRAY_BUFFER, g_vbo_handle); |
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glBufferData(GL_ARRAY_BUFFER, g_vbo_max_size, NULL, GL_DYNAMIC_DRAW); |
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glGenVertexArrays(1, &g_vao_handle); |
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glBindVertexArray(g_vao_handle); |
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glBindBuffer(GL_ARRAY_BUFFER, g_vbo_handle); |
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glEnableVertexAttribArray(g_position_location); |
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glEnableVertexAttribArray(g_uv_location); |
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glEnableVertexAttribArray(g_colour_location); |
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#define OFFSETOF(TYPE, ELEMENT) ((size_t)&(((TYPE *)0)->ELEMENT)) |
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glVertexAttribPointer(g_position_location, 2, GL_FLOAT, GL_FALSE, sizeof(ImDrawVert), (GLvoid*)OFFSETOF(ImDrawVert, pos)); |
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glVertexAttribPointer(g_uv_location, 2, GL_FLOAT, GL_FALSE, sizeof(ImDrawVert), (GLvoid*)OFFSETOF(ImDrawVert, uv)); |
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glVertexAttribPointer(g_colour_location, 4, GL_UNSIGNED_BYTE, GL_TRUE, sizeof(ImDrawVert), (GLvoid*)OFFSETOF(ImDrawVert, col)); |
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#undef OFFSETOF |
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glBindVertexArray(0); |
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glBindBuffer(GL_ARRAY_BUFFER, 0); |
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} |
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bool ImGui_ImplGlfwGL3_Init(GLFWwindow* window, bool install_callbacks) |
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{ |
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InitGL(); |
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g_window = window; |
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ImGuiIO& io = ImGui::GetIO(); |
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io.KeyMap[ImGuiKey_Tab] = GLFW_KEY_TAB; // Keyboard mapping. ImGui will use those indices to peek into the io.KeyDown[] array. |
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io.KeyMap[ImGuiKey_LeftArrow] = GLFW_KEY_LEFT; |
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io.KeyMap[ImGuiKey_RightArrow] = GLFW_KEY_RIGHT; |
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io.KeyMap[ImGuiKey_UpArrow] = GLFW_KEY_UP; |
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io.KeyMap[ImGuiKey_DownArrow] = GLFW_KEY_DOWN; |
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io.KeyMap[ImGuiKey_Home] = GLFW_KEY_HOME; |
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io.KeyMap[ImGuiKey_End] = GLFW_KEY_END; |
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io.KeyMap[ImGuiKey_Delete] = GLFW_KEY_DELETE; |
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io.KeyMap[ImGuiKey_Backspace] = GLFW_KEY_BACKSPACE; |
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io.KeyMap[ImGuiKey_Enter] = GLFW_KEY_ENTER; |
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io.KeyMap[ImGuiKey_Escape] = GLFW_KEY_ESCAPE; |
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io.KeyMap[ImGuiKey_A] = GLFW_KEY_A; |
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io.KeyMap[ImGuiKey_C] = GLFW_KEY_C; |
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io.KeyMap[ImGuiKey_V] = GLFW_KEY_V; |
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io.KeyMap[ImGuiKey_X] = GLFW_KEY_X; |
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io.KeyMap[ImGuiKey_Y] = GLFW_KEY_Y; |
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io.KeyMap[ImGuiKey_Z] = GLFW_KEY_Z; |
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io.RenderDrawListsFn = ImGui_ImplGlfwGL3_RenderDrawLists; |
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io.SetClipboardTextFn = ImGui_ImplGlfwGL3_SetClipboardText; |
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io.GetClipboardTextFn = ImGui_ImplGlfwGL3_GetClipboardText; |
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#ifdef _MSC_VER |
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io.ImeWindowHandle = glfwGetWin32Window(g_window); |
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#endif |
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if (install_callbacks) |
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{ |
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glfwSetMouseButtonCallback(window, ImGui_ImplGlfwGL3_MouseButtonCallback); |
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glfwSetScrollCallback(window, ImGui_ImplGlfwGL3_ScrollCallback); |
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glfwSetKeyCallback(window, ImGui_ImplGlfwGL3_KeyCallback); |
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glfwSetCharCallback(window, ImGui_ImplGlfwGL3_CharCallback); |
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} |
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return true; |
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} |
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void ImGui_ImplGlfwGL3_Shutdown() |
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{ |
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if (g_vao_handle) glDeleteVertexArrays(1, &g_vao_handle); |
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if (g_vbo_handle) glDeleteBuffers(1, &g_vbo_handle); |
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g_vao_handle = 0; |
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g_vbo_handle = 0; |
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glDetachShader(g_shader_handle, g_vert_handle); |
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glDeleteShader(g_vert_handle); |
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g_vert_handle = 0; |
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glDetachShader(g_shader_handle, g_frag_handle); |
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glDeleteShader(g_frag_handle); |
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g_frag_handle = 0; |
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glDeleteProgram(g_shader_handle); |
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g_shader_handle = 0; |
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GLuint tex_id = (GLuint)ImGui::GetIO().Fonts->TexID; |
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if (tex_id) |
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{ |
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glDeleteTextures(1, &tex_id); |
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ImGui::GetIO().Fonts->TexID = 0; |
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} |
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ImGui::Shutdown(); |
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} |
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void ImGui_ImplGlfwGL3_NewFrame() |
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{ |
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if (!g_font_texture_loaded) |
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ImGui_ImplGlfwGL3_LoadFontsTexture(); |
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ImGuiIO& io = ImGui::GetIO(); |
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// Setup display size (every frame to accommodate for window resizing) |
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int w, h; |
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int display_w, display_h; |
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glfwGetWindowSize(g_window, &w, &h); |
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glfwGetFramebufferSize(g_window, &display_w, &display_h); |
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io.DisplaySize = ImVec2((float)display_w, (float)display_h); |
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// Setup time step |
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double current_time = glfwGetTime(); |
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io.DeltaTime = g_time > 0.0 ? (float)(current_time - g_time) : (float)(1.0f/60.0f); |
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g_time = current_time; |
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// Setup inputs |
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// (we already got mouse wheel, keyboard keys & characters from glfw callbacks polled in glfwPollEvents()) |
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double mouse_x, mouse_y; |
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glfwGetCursorPos(g_window, &mouse_x, &mouse_y); |
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mouse_x *= (float)display_w / w; // Convert mouse coordinates to pixels |
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mouse_y *= (float)display_h / h; |
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io.MousePos = ImVec2((float)mouse_x, (float)mouse_y); // Mouse position, in pixels (set to -1,-1 if no mouse / on another screen, etc.) |
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io.MouseDown[0] = g_mouse_pressed[0] || glfwGetMouseButton(g_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. |
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io.MouseDown[1] = g_mouse_pressed[1] || glfwGetMouseButton(g_window, GLFW_MOUSE_BUTTON_RIGHT) != 0; |
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io.MouseDown[2] = g_mouse_pressed[2] || glfwGetMouseButton(g_window, GLFW_MOUSE_BUTTON_MIDDLE) != 0; |
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g_mouse_pressed[0] = false; |
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g_mouse_pressed[1] = false; |
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g_mouse_pressed[2] = false; |
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io.MouseWheel = g_mouse_wheel; |
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g_mouse_wheel = 0.0f; |
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// Start the frame |
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ImGui::NewFrame(); |
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}
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