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OpenGL example now use the fixed function-pipeline. Code down by 120 lines.
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ocornut
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ddc7f8b0b0
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cb3d503941
@ -9,80 +9,56 @@
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#endif
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static GLFWwindow* window;
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static GLuint vbo;
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static GLuint vao;
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static GLuint vertexShader;
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static GLuint fragmentShader;
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static GLuint shaderProgram;
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static GLuint fontTex;
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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 structuer)
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// We are using the fixed pipeline.
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// A faster way would be to collate all vertices from all cmd_lists into a single vertex buffer
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static void ImImpl_RenderDrawLists(ImDrawList** const cmd_lists, int cmd_lists_count)
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{
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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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if (total_vtx_count == 0)
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if (cmd_lists_count == 0)
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return;
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// Copy all vertices into a single contiguous GL buffer
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glBindBuffer(GL_ARRAY_BUFFER, vbo);
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glBindVertexArray(vao);
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glBufferData(GL_ARRAY_BUFFER, total_vtx_count * sizeof(ImDrawVert), NULL, GL_STREAM_DRAW);
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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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// Setup render state: alpha-blending enabled, no face culling, no depth testing
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glEnable(GL_BLEND);
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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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glEnableClientState(GL_VERTEX_ARRAY);
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glEnableClientState(GL_TEXTURE_COORD_ARRAY);
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glEnableClientState(GL_COLOR_ARRAY);
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// Bind texture and enable our shader
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// Bind texture
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glBindTexture(GL_TEXTURE_2D, fontTex);
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glUseProgram(shaderProgram);
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const GLint uniMVP = glGetUniformLocation(shaderProgram, "MVP");
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const GLint uniClipRect = glGetUniformLocation(shaderProgram, "ClipRect");
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glEnable(GL_TEXTURE_2D);
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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 mvp[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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glUniformMatrix4fv(uniMVP, 1, GL_FALSE, &mvp[0][0]);
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// Setup matrices
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glMatrixMode(GL_PROJECTION);
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glLoadIdentity();
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glOrtho(0.0f, ImGui::GetIO().DisplaySize.x, ImGui::GetIO().DisplaySize.y, 0.0f, -1.0f, +1.0f);
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glMatrixMode(GL_MODELVIEW);
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glLoadIdentity();
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// Render command lists
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int vtx_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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const unsigned char* vtx_buffer = (const unsigned char*)cmd_list->vtx_buffer.begin();
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glVertexPointer(2, GL_FLOAT, sizeof(ImDrawVert), (void*)(vtx_buffer));
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glTexCoordPointer(2, GL_FLOAT, sizeof(ImDrawVert), (void*)(vtx_buffer+8));
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glColorPointer(4, GL_UNSIGNED_BYTE, sizeof(ImDrawVert), (void*)(vtx_buffer+16));
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int vtx_offset = 0;
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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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glUniform4fv(uniClipRect, 1, (float*)&pcmd->clip_rect);
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glScissor((int)pcmd->clip_rect.x, (int)pcmd->clip_rect.y, (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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}
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// Cleanup GL state
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glBindTexture(GL_TEXTURE_2D, 0);
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glBindVertexArray(0);
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glBindBuffer(GL_ARRAY_BUFFER, 0);
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glUseProgram(0);
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glDisable(GL_SCISSOR_TEST);
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}
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static const char* ImImpl_GetClipboardTextFn()
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@ -103,38 +79,6 @@ static void ImImpl_SetClipboardTextFn(const char* text, const char* text_end)
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free(buf);
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}
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// Shader sources
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const GLchar* vertexSource =
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"#version 150 core\n"
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"uniform mat4 MVP;"
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"in vec2 i_pos;"
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"in vec2 i_uv;"
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"in vec4 i_col;"
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"out vec4 col;"
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"out vec2 pixel_pos;"
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"out vec2 uv;"
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"void main() {"
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" col = i_col;"
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" pixel_pos = i_pos;"
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" uv = i_uv;"
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" gl_Position = MVP * vec4(i_pos.x, i_pos.y, 0.0f, 1.0f);"
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"}";
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const GLchar* fragmentSource =
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"#version 150 core\n"
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"uniform sampler2D Tex;"
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"uniform vec4 ClipRect;"
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"in vec4 col;"
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"in vec2 pixel_pos;"
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"in vec2 uv;"
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"out vec4 o_col;"
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"void main() {"
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" o_col = texture(Tex, uv) * col;"
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//" if (pixel_pos.x < ClipRect.x || pixel_pos.y < ClipRect.y || pixel_pos.x > ClipRect.z || pixel_pos.y > ClipRect.w) discard;" // Clipping: using discard
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//" if (step(ClipRect.x,pixel_pos.x) * step(ClipRect.y,pixel_pos.y) * step(pixel_pos.x,ClipRect.z) * step(pixel_pos.y,ClipRect.w) < 1.0f) discard;" // Clipping: using discard and step
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" o_col.w *= (step(ClipRect.x,pixel_pos.x) * step(ClipRect.y,pixel_pos.y) * step(pixel_pos.x,ClipRect.z) * step(pixel_pos.y,ClipRect.w));" // Clipping: branch-less, set alpha 0.0f
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"}";
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// GLFW callbacks to get events
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static void glfw_error_callback(int error, const char* description)
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{
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@ -172,26 +116,14 @@ void InitGL()
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if (!glfwInit())
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exit(1);
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glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
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glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 2);
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glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
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glfwWindowHint(GLFW_OPENGL_FORWARD_COMPAT, GL_TRUE);
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glfwWindowHint(GLFW_REFRESH_RATE, 60);
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glfwWindowHint(GLFW_RESIZABLE, GL_FALSE);
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window = glfwCreateWindow(1280, 720, "ImGui OpenGL example", NULL, NULL);
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glfwMakeContextCurrent(window);
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glfwSetKeyCallback(window, glfw_key_callback);
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glfwSetScrollCallback(window, glfw_scroll_callback);
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glfwSetCharCallback(window, glfw_char_callback);
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glewExperimental = GL_TRUE;
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glewInit();
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// After calling glewInit() our GL error state may be GL_INVALID_ENUM
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const GLenum err = glGetError();
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(void)err;
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IM_ASSERT(err == GL_NO_ERROR || err == GL_INVALID_ENUM);
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}
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void InitImGui()
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@ -203,7 +135,7 @@ void InitImGui()
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io.DisplaySize = ImVec2((float)w, (float)h); // Display size, in pixels. For clamping windows positions.
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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)
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io.PixelCenterOffset = 0.5f; // Align OpenGL texels
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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 that we will update during the application lifetime.
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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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@ -225,68 +157,11 @@ void InitImGui()
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io.SetClipboardTextFn = ImImpl_SetClipboardTextFn;
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io.GetClipboardTextFn = ImImpl_GetClipboardTextFn;
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// Setup graphics backend
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GLint status = GL_TRUE;
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GLenum err = GL_NO_ERROR;
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err = glGetError(); IM_ASSERT(err == GL_NO_ERROR);
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// Create and compile the vertex shader
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vertexShader = glCreateShader(GL_VERTEX_SHADER);
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glShaderSource(vertexShader, 1, &vertexSource, NULL);
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glCompileShader(vertexShader);
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glGetShaderiv(vertexShader, GL_COMPILE_STATUS, &status);
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if (status != GL_TRUE)
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{
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char buffer[512];
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glGetShaderInfoLog(vertexShader, 1024, NULL, buffer);
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printf("%s", buffer);
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IM_ASSERT(status == GL_TRUE);
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}
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// Create and compile the fragment shader
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fragmentShader = glCreateShader(GL_FRAGMENT_SHADER);
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glShaderSource(fragmentShader, 1, &fragmentSource, NULL);
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glCompileShader(fragmentShader);
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glGetShaderiv(vertexShader, GL_COMPILE_STATUS, &status);
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IM_ASSERT(status == GL_TRUE);
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// Link the vertex and fragment shader into a shader program
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shaderProgram = glCreateProgram();
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glAttachShader(shaderProgram, vertexShader);
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glAttachShader(shaderProgram, fragmentShader);
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glBindFragDataLocation(shaderProgram, 0, "o_col");
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glLinkProgram(shaderProgram);
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glGetProgramiv(shaderProgram, GL_LINK_STATUS, &status);
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IM_ASSERT(status == GL_TRUE);
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// Create Vertex Buffer Objects & Vertex Array Objects
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glGenBuffers(1, &vbo);
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glBindBuffer(GL_ARRAY_BUFFER, vbo);
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glGenVertexArrays(1, &vao);
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glBindVertexArray(vao);
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GLint posAttrib = glGetAttribLocation(shaderProgram, "i_pos");
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glVertexAttribPointer(posAttrib, 2, GL_FLOAT, GL_FALSE, sizeof(ImDrawVert), 0);
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glEnableVertexAttribArray(posAttrib);
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GLint uvAttrib = glGetAttribLocation(shaderProgram, "i_uv");
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glEnableVertexAttribArray(uvAttrib);
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glVertexAttribPointer(uvAttrib, 2, GL_FLOAT, GL_FALSE, sizeof(ImDrawVert), (void*)(2*sizeof(float)));
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GLint colAttrib = glGetAttribLocation(shaderProgram, "i_col");
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glVertexAttribPointer(colAttrib, 4, GL_UNSIGNED_BYTE, GL_TRUE, sizeof(ImDrawVert), (void*)(4*sizeof(float)));
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glEnableVertexAttribArray(colAttrib);
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err = glGetError(); IM_ASSERT(err == GL_NO_ERROR);
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glBindVertexArray(0);
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glBindBuffer(GL_ARRAY_BUFFER, 0);
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// Load font texture
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glGenTextures(1, &fontTex);
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glBindTexture(GL_TEXTURE_2D, fontTex);
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glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
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glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
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const void* png_data;
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unsigned int png_size;
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ImGui::GetDefaultFontData(NULL, NULL, &png_data, &png_size);
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@ -299,13 +174,6 @@ void InitImGui()
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void Shutdown()
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{
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ImGui::Shutdown();
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glDeleteProgram(shaderProgram);
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glDeleteShader(fragmentShader);
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glDeleteShader(vertexShader);
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glDeleteBuffers(1, &vbo);
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glDeleteVertexArrays(1, &vao);
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glfwTerminate();
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}
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@ -368,6 +236,7 @@ int main(int argc, char** argv)
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}
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// 3) Rendering
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glViewport(0, 0, (int)io.DisplaySize.x, (int)io.DisplaySize.y);
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glClearColor(0.8f, 0.6f, 0.6f, 1.0f);
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glClear(GL_COLOR_BUFFER_BIT);
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ImGui::Render();
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