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Sync OpenGL code with imgui/backends/imgui_impl_opengl2
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@eliasdaler
eliasdaler committed Apr 9, 2021
1 parent 5c3027a commit 224fe6c
Showing 1 changed file with 133 additions and 56 deletions.
189 changes: 133 additions & 56 deletions imgui-SFML.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -381,8 +381,8 @@ void Update(sf::Window& window, sf::RenderTarget& target, sf::Time dt) {

void Update(const sf::Vector2i& mousePos, const sf::Vector2f& displaySize, sf::Time dt) {
ImGuiIO& io = ImGui::GetIO();
io.DisplaySize = ImVec2(displaySize.x, displaySize.y);

io.DisplaySize = ImVec2(displaySize.x, displaySize.y);
io.DeltaTime = dt.asSeconds();

if (s_windowHasFocus) {
Expand Down Expand Up @@ -440,8 +440,10 @@ void Update(const sf::Vector2i& mousePos, const sf::Vector2f& displaySize, sf::T

void Render(sf::RenderTarget& target) {
target.resetGLStates();
target.pushGLStates();
ImGui::Render();
RenderDrawLists(ImGui::GetDrawData());
target.popGLStates();
}

void Render() {
Expand All @@ -450,7 +452,7 @@ void Render() {
}

void Shutdown() {
ImGui::GetIO().Fonts->TexID = (ImTextureID)NULL;
ImGui::GetIO().Fonts->SetTexID(0);

if (s_fontTexture) { // if internal texture was created, we delete it
delete s_fontTexture;
Expand Down Expand Up @@ -480,7 +482,8 @@ void UpdateFontTexture() {
texture.create(width, height);
texture.update(pixels);

io.Fonts->TexID = convertGLTextureHandleToImTextureID(texture.getNativeHandle());
ImTextureID texID = convertGLTextureHandleToImTextureID(texture.getNativeHandle());
io.Fonts->SetTexID(texID);
}

sf::Texture& GetFontTexture() {
Expand Down Expand Up @@ -705,6 +708,51 @@ GLuint convertImTextureIDToGLTextureHandle(ImTextureID textureID) {
return glTextureHandle;
}

// copied from imgui/backends/imgui_impl_opengl2.cpp
void SetupRenderState(ImDrawData* draw_data, int fb_width, int fb_height) {
// Setup render state: alpha-blending enabled, no face culling, no depth testing, scissor
// enabled, vertex/texcoord/color pointers, polygon fill.
glEnable(GL_BLEND);
glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
// glBlendFuncSeparate(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA, GL_ONE, GL_ONE_MINUS_SRC_ALPHA); //
// In order to composite our output buffer we need to preserve alpha
glDisable(GL_CULL_FACE);
glDisable(GL_DEPTH_TEST);
glDisable(GL_STENCIL_TEST);
glDisable(GL_LIGHTING);
glDisable(GL_COLOR_MATERIAL);
glEnable(GL_SCISSOR_TEST);
glEnableClientState(GL_VERTEX_ARRAY);
glEnableClientState(GL_TEXTURE_COORD_ARRAY);
glEnableClientState(GL_COLOR_ARRAY);
glDisableClientState(GL_NORMAL_ARRAY);
glEnable(GL_TEXTURE_2D);
glPolygonMode(GL_FRONT_AND_BACK, GL_FILL);
glShadeModel(GL_SMOOTH);
glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);

// Setup viewport, orthographic projection matrix
// Our visible imgui space lies from draw_data->DisplayPos (top left) to
// draw_data->DisplayPos+data_data->DisplaySize (bottom right). DisplayPos is (0,0) for single
// viewport apps.
glViewport(0, 0, (GLsizei)fb_width, (GLsizei)fb_height);
glMatrixMode(GL_PROJECTION);
glPushMatrix();
glLoadIdentity();
#ifdef GL_VERSION_ES_CL_1_1
glOrthof(draw_data->DisplayPos.x, draw_data->DisplayPos.x + draw_data->DisplaySize.x,
draw_data->DisplayPos.y + draw_data->DisplaySize.y, draw_data->DisplayPos.y, -1.0f,
+1.0f);
#else
glOrtho(draw_data->DisplayPos.x, draw_data->DisplayPos.x + draw_data->DisplaySize.x,
draw_data->DisplayPos.y + draw_data->DisplaySize.y, draw_data->DisplayPos.y, -1.0f,
+1.0f);
#endif
glMatrixMode(GL_MODELVIEW);
glPushMatrix();
glLoadIdentity();
}

// Rendering callback
void RenderDrawLists(ImDrawData* draw_data) {
ImGui::GetDrawData();
Expand All @@ -715,86 +763,115 @@ void RenderDrawLists(ImDrawData* draw_data) {
ImGuiIO& io = ImGui::GetIO();
assert(io.Fonts->TexID != (ImTextureID)NULL); // You forgot to create and set font texture

// scale stuff (needed for proper handling of window resize)
int fb_width = static_cast<int>(io.DisplaySize.x * io.DisplayFramebufferScale.x);
int fb_height = static_cast<int>(io.DisplaySize.y * io.DisplayFramebufferScale.y);
if (fb_width == 0 || fb_height == 0) {
return;
}
// Avoid rendering when minimized, scale coordinates for retina displays (screen coordinates !=
// framebuffer coordinates)
int fb_width = (int)(draw_data->DisplaySize.x * draw_data->FramebufferScale.x);
int fb_height = (int)(draw_data->DisplaySize.y * draw_data->FramebufferScale.y);
if (fb_width == 0 || fb_height == 0) return;
draw_data->ScaleClipRects(io.DisplayFramebufferScale);

#ifdef GL_VERSION_ES_CL_1_1
GLint last_program, last_texture, last_array_buffer, last_element_array_buffer;
// Backup GL state
// Backup GL state
GLint last_texture;
glGetIntegerv(GL_TEXTURE_BINDING_2D, &last_texture);
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);
GLint last_shade_model;
glGetIntegerv(GL_SHADE_MODEL, &last_shade_model);
GLint last_tex_env_mode;
glGetTexEnviv(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, &last_tex_env_mode);

#ifdef GL_VERSION_ES_CL_1_1
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);
#else
glPushAttrib(GL_ENABLE_BIT | GL_COLOR_BUFFER_BIT | GL_TRANSFORM_BIT);
#endif

glEnable(GL_BLEND);
glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
glDisable(GL_CULL_FACE);
glDisable(GL_DEPTH_TEST);
glEnable(GL_SCISSOR_TEST);
glEnable(GL_TEXTURE_2D);
glDisable(GL_LIGHTING);
glEnableClientState(GL_VERTEX_ARRAY);
glEnableClientState(GL_COLOR_ARRAY);
glEnableClientState(GL_TEXTURE_COORD_ARRAY);

glViewport(0, 0, (GLsizei)fb_width, (GLsizei)fb_height);
// Setup desired GL state
SetupRenderState(draw_data, fb_width, fb_height);

glMatrixMode(GL_TEXTURE);
glLoadIdentity();
// Will project scissor/clipping rectangles into framebuffer space
ImVec2 clip_off = draw_data->DisplayPos; // (0,0) unless using multi-viewports
ImVec2 clip_scale = draw_data->FramebufferScale; // (1,1) unless using retina display which are
// often (2,2)

glMatrixMode(GL_PROJECTION);
glLoadIdentity();

#ifdef GL_VERSION_ES_CL_1_1
glOrthof(0.0f, io.DisplaySize.x, io.DisplaySize.y, 0.0f, -1.0f, +1.0f);
#else
glOrtho(0.0f, io.DisplaySize.x, io.DisplaySize.y, 0.0f, -1.0f, +1.0f);
#endif

glMatrixMode(GL_MODELVIEW);
glLoadIdentity();

for (int n = 0; n < draw_data->CmdListsCount; ++n) {
// Render command lists
for (int n = 0; n < draw_data->CmdListsCount; n++) {
const ImDrawList* cmd_list = draw_data->CmdLists[n];
const unsigned char* vtx_buffer = (const unsigned char*)&cmd_list->VtxBuffer.front();
const ImDrawIdx* idx_buffer = &cmd_list->IdxBuffer.front();

const ImDrawVert* vtx_buffer = cmd_list->VtxBuffer.Data;
const ImDrawIdx* idx_buffer = cmd_list->IdxBuffer.Data;
glVertexPointer(2, GL_FLOAT, sizeof(ImDrawVert),
(void*)(vtx_buffer + offsetof(ImDrawVert, pos)));
(const GLvoid*)((const char*)vtx_buffer + IM_OFFSETOF(ImDrawVert, pos)));
glTexCoordPointer(2, GL_FLOAT, sizeof(ImDrawVert),
(void*)(vtx_buffer + offsetof(ImDrawVert, uv)));
(const GLvoid*)((const char*)vtx_buffer + IM_OFFSETOF(ImDrawVert, uv)));
glColorPointer(4, GL_UNSIGNED_BYTE, sizeof(ImDrawVert),
(void*)(vtx_buffer + offsetof(ImDrawVert, col)));
(const GLvoid*)((const char*)vtx_buffer + IM_OFFSETOF(ImDrawVert, col)));

for (int cmd_i = 0; cmd_i < cmd_list->CmdBuffer.size(); ++cmd_i) {
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);
// User callback, registered via ImDrawList::AddCallback()
// (ImDrawCallback_ResetRenderState is a special callback value used by the user to
// request the renderer to reset render state.)
if (pcmd->UserCallback == ImDrawCallback_ResetRenderState)
SetupRenderState(draw_data, fb_width, fb_height);
else
pcmd->UserCallback(cmd_list, pcmd);
} else {
GLuint textureHandle = convertImTextureIDToGLTextureHandle(pcmd->TextureId);
glBindTexture(GL_TEXTURE_2D, textureHandle);
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);
// Project scissor/clipping rectangles into framebuffer space
ImVec4 clip_rect;
clip_rect.x = (pcmd->ClipRect.x - clip_off.x) * clip_scale.x;
clip_rect.y = (pcmd->ClipRect.y - clip_off.y) * clip_scale.y;
clip_rect.z = (pcmd->ClipRect.z - clip_off.x) * clip_scale.x;
clip_rect.w = (pcmd->ClipRect.w - clip_off.y) * clip_scale.y;

if (clip_rect.x < fb_width && clip_rect.y < fb_height && clip_rect.z >= 0.0f &&
clip_rect.w >= 0.0f) {
// Apply scissor/clipping rectangle
glScissor((int)clip_rect.x, (int)(fb_height - clip_rect.w),
(int)(clip_rect.z - clip_rect.x), (int)(clip_rect.w - clip_rect.y));

// Bind texture, Draw
GLuint textureHandle = convertImTextureIDToGLTextureHandle(pcmd->TextureId);
glBindTexture(GL_TEXTURE_2D, textureHandle);
glDrawElements(GL_TRIANGLES, (GLsizei)pcmd->ElemCount, GL_UNSIGNED_SHORT,
idx_buffer);
}
}
idx_buffer += pcmd->ElemCount;
}
}

// Restore modified GL state
glDisableClientState(GL_COLOR_ARRAY);
glDisableClientState(GL_TEXTURE_COORD_ARRAY);
glDisableClientState(GL_VERTEX_ARRAY);
glBindTexture(GL_TEXTURE_2D, (GLuint)last_texture);
glMatrixMode(GL_MODELVIEW);
glPopMatrix();
glMatrixMode(GL_PROJECTION);
glPopMatrix();
glPopAttrib();
glPolygonMode(GL_FRONT, (GLenum)last_polygon_mode[0]);
glPolygonMode(GL_BACK, (GLenum)last_polygon_mode[1]);
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]);
glShadeModel(last_shade_model);
glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, last_tex_env_mode);

#ifdef GL_VERSION_ES_CL_1_1
glBindTexture(GL_TEXTURE_2D, last_texture);
glBindBuffer(GL_ARRAY_BUFFER, last_array_buffer);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, last_element_array_buffer);
glDisable(GL_SCISSOR_TEST);
#else
glPopAttrib();
#endif
}

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