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Examples: GLFW+GL2: Moved glfw, gl2 files to root folder, split imgui_impl_glfw_gl2 into _opengl2 and reused imgui_impl_glfw

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omar
2018-02-16 22:01:48 +01:00
parent b0a8734c92
commit c8a9969511
14 changed files with 226 additions and 380 deletions
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examples/imgui_impl_opengl3.cpp Normal file
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#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.
// Data
static GLuint g_FontTexture = 0;
static int g_ShaderHandle = 0, g_VertHandle = 0, g_FragHandle = 0;
static int g_AttribLocationTex = 0, g_AttribLocationProjMtx = 0;
static int g_AttribLocationPosition = 0, g_AttribLocationUV = 0, g_AttribLocationColor = 0;
static unsigned int g_VboHandle = 0, g_VaoHandle = 0, g_ElementsHandle = 0;
// Functions
bool ImGui_ImplOpenGL3_Init()
{
return true;
}
void ImGui_ImplOpenGL3_Shutdown()
{
ImGui_ImplOpenGL3_DestroyDeviceObjects();
}
void ImGui_ImplOpenGL3_NewFrame()
{
if (!g_FontTexture)
ImGui_ImplOpenGL3_CreateDeviceObjects();
}
// OpenGL3 Render function.
// (this used to be set in io.RenderDrawListsFn and called by ImGui::Render(), but you can now call this directly from your main loop)
// Note that this implementation is little overcomplicated because we are saving/setting up/restoring every OpenGL state explicitly, in order to be able to run within any OpenGL engine that doesn't do so.
void ImGui_ImplOpenGL3_RenderDrawData(ImDrawData* draw_data)
{
// Avoid rendering when minimized, scale coordinates for retina displays (screen coordinates != framebuffer coordinates)
ImGuiIO& io = ImGui::GetIO();
int fb_width = (int)(io.DisplaySize.x * io.DisplayFramebufferScale.x);
int fb_height = (int)(io.DisplaySize.y * io.DisplayFramebufferScale.y);
if (fb_width == 0 || fb_height == 0)
return;
draw_data->ScaleClipRects(io.DisplayFramebufferScale);
// Backup GL state
GLenum last_active_texture; glGetIntegerv(GL_ACTIVE_TEXTURE, (GLint*)&last_active_texture);
glActiveTexture(GL_TEXTURE0);
GLint last_program; glGetIntegerv(GL_CURRENT_PROGRAM, &last_program);
GLint last_texture; glGetIntegerv(GL_TEXTURE_BINDING_2D, &last_texture);
GLint last_sampler; glGetIntegerv(GL_SAMPLER_BINDING, &last_sampler);
GLint last_array_buffer; glGetIntegerv(GL_ARRAY_BUFFER_BINDING, &last_array_buffer);
GLint last_element_array_buffer; glGetIntegerv(GL_ELEMENT_ARRAY_BUFFER_BINDING, &last_element_array_buffer);
GLint last_vertex_array; glGetIntegerv(GL_VERTEX_ARRAY_BINDING, &last_vertex_array);
GLint last_polygon_mode[2]; glGetIntegerv(GL_POLYGON_MODE, last_polygon_mode);
GLint last_viewport[4]; glGetIntegerv(GL_VIEWPORT, last_viewport);
GLint last_scissor_box[4]; glGetIntegerv(GL_SCISSOR_BOX, last_scissor_box);
GLenum last_blend_src_rgb; glGetIntegerv(GL_BLEND_SRC_RGB, (GLint*)&last_blend_src_rgb);
GLenum last_blend_dst_rgb; glGetIntegerv(GL_BLEND_DST_RGB, (GLint*)&last_blend_dst_rgb);
GLenum last_blend_src_alpha; glGetIntegerv(GL_BLEND_SRC_ALPHA, (GLint*)&last_blend_src_alpha);
GLenum last_blend_dst_alpha; glGetIntegerv(GL_BLEND_DST_ALPHA, (GLint*)&last_blend_dst_alpha);
GLenum last_blend_equation_rgb; glGetIntegerv(GL_BLEND_EQUATION_RGB, (GLint*)&last_blend_equation_rgb);
GLenum last_blend_equation_alpha; glGetIntegerv(GL_BLEND_EQUATION_ALPHA, (GLint*)&last_blend_equation_alpha);
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);
GLboolean last_enable_scissor_test = glIsEnabled(GL_SCISSOR_TEST);
// Setup render state: alpha-blending enabled, no face culling, no depth testing, scissor enabled, polygon fill
glEnable(GL_BLEND);
glBlendEquation(GL_FUNC_ADD);
glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
glDisable(GL_CULL_FACE);
glDisable(GL_DEPTH_TEST);
glEnable(GL_SCISSOR_TEST);
glPolygonMode(GL_FRONT_AND_BACK, GL_FILL);
// Setup viewport, orthographic projection matrix
glViewport(0, 0, (GLsizei)fb_width, (GLsizei)fb_height);
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 },
{ 0.0f, 0.0f, -1.0f, 0.0f },
{ -1.0f, 1.0f, 0.0f, 1.0f },
};
glUseProgram(g_ShaderHandle);
glUniform1i(g_AttribLocationTex, 0);
glUniformMatrix4fv(g_AttribLocationProjMtx, 1, GL_FALSE, &ortho_projection[0][0]);
glBindVertexArray(g_VaoHandle);
glBindSampler(0, 0); // Rely on combined texture/sampler state.
for (int n = 0; n < draw_data->CmdListsCount; n++)
{
const ImDrawList* cmd_list = draw_data->CmdLists[n];
const ImDrawIdx* idx_buffer_offset = 0;
glBindBuffer(GL_ARRAY_BUFFER, g_VboHandle);
glBufferData(GL_ARRAY_BUFFER, (GLsizeiptr)cmd_list->VtxBuffer.Size * sizeof(ImDrawVert), (const GLvoid*)cmd_list->VtxBuffer.Data, GL_STREAM_DRAW);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, g_ElementsHandle);
glBufferData(GL_ELEMENT_ARRAY_BUFFER, (GLsizeiptr)cmd_list->IdxBuffer.Size * sizeof(ImDrawIdx), (const GLvoid*)cmd_list->IdxBuffer.Data, GL_STREAM_DRAW);
for (int cmd_i = 0; cmd_i < cmd_list->CmdBuffer.Size; cmd_i++)
{
const ImDrawCmd* pcmd = &cmd_list->CmdBuffer[cmd_i];
if (pcmd->UserCallback)
{
pcmd->UserCallback(cmd_list, pcmd);
}
else
{
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;
}
}
// Restore modified GL state
glUseProgram(last_program);
glBindTexture(GL_TEXTURE_2D, last_texture);
glBindSampler(0, last_sampler);
glActiveTexture(last_active_texture);
glBindVertexArray(last_vertex_array);
glBindBuffer(GL_ARRAY_BUFFER, last_array_buffer);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, last_element_array_buffer);
glBlendEquationSeparate(last_blend_equation_rgb, last_blend_equation_alpha);
glBlendFuncSeparate(last_blend_src_rgb, last_blend_dst_rgb, last_blend_src_alpha, last_blend_dst_alpha);
if (last_enable_blend) glEnable(GL_BLEND); else glDisable(GL_BLEND);
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);
glPolygonMode(GL_FRONT_AND_BACK, last_polygon_mode[0]);
glViewport(last_viewport[0], last_viewport[1], (GLsizei)last_viewport[2], (GLsizei)last_viewport[3]);
glScissor(last_scissor_box[0], last_scissor_box[1], (GLsizei)last_scissor_box[2], (GLsizei)last_scissor_box[3]);
}
bool ImGui_ImplOpenGL3_CreateFontsTexture()
{
// Build texture atlas
ImGuiIO& io = ImGui::GetIO();
unsigned char* pixels;
int width, height;
io.Fonts->GetTexDataAsRGBA32(&pixels, &width, &height); // Load as RGBA 32-bits (75% of the memory is wasted, but default font is so small) because it is more likely to be compatible with user's existing shaders. If your ImTextureId represent a higher-level concept than just a GL texture id, consider calling GetTexDataAsAlpha8() instead to save on GPU memory.
// Upload texture to graphics system
GLint last_texture;
glGetIntegerv(GL_TEXTURE_BINDING_2D, &last_texture);
glGenTextures(1, &g_FontTexture);
glBindTexture(GL_TEXTURE_2D, g_FontTexture);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
glPixelStorei(GL_UNPACK_ROW_LENGTH, 0);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, pixels);
// Store our identifier
io.Fonts->TexID = (void *)(intptr_t)g_FontTexture;
// Restore state
glBindTexture(GL_TEXTURE_2D, last_texture);
return true;
}
void ImGui_ImplOpenGL3_DestroyFontsTexture()
{
if (g_FontTexture)
{
ImGuiIO& io = ImGui::GetIO();
glDeleteTextures(1, &g_FontTexture);
io.Fonts->TexID = 0;
g_FontTexture = 0;
}
}
bool ImGui_ImplOpenGL3_CreateDeviceObjects()
{
// Backup GL state
GLint last_texture, last_array_buffer, last_vertex_array;
glGetIntegerv(GL_TEXTURE_BINDING_2D, &last_texture);
glGetIntegerv(GL_ARRAY_BUFFER_BINDING, &last_array_buffer);
glGetIntegerv(GL_VERTEX_ARRAY_BINDING, &last_vertex_array);
// Create shaders
const GLchar *vertex_shader =
"#version 150\n"
"uniform mat4 ProjMtx;\n"
"in vec2 Position;\n"
"in vec2 UV;\n"
"in vec4 Color;\n"
"out vec2 Frag_UV;\n"
"out vec4 Frag_Color;\n"
"void main()\n"
"{\n"
" Frag_UV = UV;\n"
" Frag_Color = Color;\n"
" gl_Position = ProjMtx * vec4(Position.xy,0,1);\n"
"}\n";
const GLchar* fragment_shader =
"#version 150\n"
"uniform sampler2D Texture;\n"
"in vec2 Frag_UV;\n"
"in vec4 Frag_Color;\n"
"out vec4 Out_Color;\n"
"void main()\n"
"{\n"
" Out_Color = Frag_Color * texture( Texture, Frag_UV.st);\n"
"}\n";
g_ShaderHandle = glCreateProgram();
g_VertHandle = glCreateShader(GL_VERTEX_SHADER);
g_FragHandle = glCreateShader(GL_FRAGMENT_SHADER);
glShaderSource(g_VertHandle, 1, &vertex_shader, 0);
glShaderSource(g_FragHandle, 1, &fragment_shader, 0);
glCompileShader(g_VertHandle);
glCompileShader(g_FragHandle);
glAttachShader(g_ShaderHandle, g_VertHandle);
glAttachShader(g_ShaderHandle, g_FragHandle);
glLinkProgram(g_ShaderHandle);
g_AttribLocationTex = glGetUniformLocation(g_ShaderHandle, "Texture");
g_AttribLocationProjMtx = glGetUniformLocation(g_ShaderHandle, "ProjMtx");
g_AttribLocationPosition = glGetAttribLocation(g_ShaderHandle, "Position");
g_AttribLocationUV = glGetAttribLocation(g_ShaderHandle, "UV");
g_AttribLocationColor = glGetAttribLocation(g_ShaderHandle, "Color");
glGenBuffers(1, &g_VboHandle);
glGenBuffers(1, &g_ElementsHandle);
glGenVertexArrays(1, &g_VaoHandle);
glBindVertexArray(g_VaoHandle);
glBindBuffer(GL_ARRAY_BUFFER, g_VboHandle);
glEnableVertexAttribArray(g_AttribLocationPosition);
glEnableVertexAttribArray(g_AttribLocationUV);
glEnableVertexAttribArray(g_AttribLocationColor);
glVertexAttribPointer(g_AttribLocationPosition, 2, GL_FLOAT, GL_FALSE, sizeof(ImDrawVert), (GLvoid*)IM_OFFSETOF(ImDrawVert, pos));
glVertexAttribPointer(g_AttribLocationUV, 2, GL_FLOAT, GL_FALSE, sizeof(ImDrawVert), (GLvoid*)IM_OFFSETOF(ImDrawVert, uv));
glVertexAttribPointer(g_AttribLocationColor, 4, GL_UNSIGNED_BYTE, GL_TRUE, sizeof(ImDrawVert), (GLvoid*)IM_OFFSETOF(ImDrawVert, col));
ImGui_ImplOpenGL3_CreateFontsTexture();
// Restore modified GL state
glBindTexture(GL_TEXTURE_2D, last_texture);
glBindBuffer(GL_ARRAY_BUFFER, last_array_buffer);
glBindVertexArray(last_vertex_array);
return true;
}
void ImGui_ImplOpenGL3_DestroyDeviceObjects()
{
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;
if (g_ShaderHandle && g_VertHandle) glDetachShader(g_ShaderHandle, g_VertHandle);
if (g_VertHandle) glDeleteShader(g_VertHandle);
g_VertHandle = 0;
if (g_ShaderHandle && g_FragHandle) glDetachShader(g_ShaderHandle, g_FragHandle);
if (g_FragHandle) glDeleteShader(g_FragHandle);
g_FragHandle = 0;
if (g_ShaderHandle) glDeleteProgram(g_ShaderHandle);
g_ShaderHandle = 0;
ImGui_ImplOpenGL3_DestroyFontsTexture();
}