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ImDrawList::AddCallback() allows for custom rendering (e.g. 3D scene inside a imgui widget))

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docking
ocornut 10 years ago
parent 82666cdc57
commit 2ecc285919
2 changed files with 71 additions and 49 deletions
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66
imgui.cpp
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@ -6039,81 +6039,84 @@ void ImDrawList::Clear()
texture_id_stack.resize(0); texture_id_stack.resize(0);
} }
// This is useful if you need to force-create a new draw call (to allow for depending rendering / blending). void ImDrawList::AddDrawCmd()
// Otherwise primitives are merged into the same draw-call as much as possible.
void ImDrawList::SplitDrawCmd()
{ {
ImDrawCmd draw_cmd; ImDrawCmd draw_cmd;
draw_cmd.vtx_count = 0; draw_cmd.vtx_count = 0;
draw_cmd.clip_rect = clip_rect_stack.back(); draw_cmd.clip_rect = clip_rect_stack.empty() ? GNullClipRect : clip_rect_stack.back();
draw_cmd.texture_id = texture_id_stack.back(); draw_cmd.texture_id = texture_id_stack.empty() ? NULL : texture_id_stack.back();
draw_cmd.user_callback = NULL;
draw_cmd.user_callback_data = NULL;
commands.push_back(draw_cmd); commands.push_back(draw_cmd);
} }
void ImDrawList::SetClipRect(const ImVec4& clip_rect) void ImDrawList::AddCallback(ImDrawCallback callback, void* callback_data)
{ {
ImDrawCmd* current_cmd = commands.empty() ? NULL : &commands.back(); ImDrawCmd* current_cmd = commands.empty() ? NULL : &commands.back();
if (current_cmd && current_cmd->vtx_count == 0) if (!current_cmd || current_cmd->vtx_count != 0 || current_cmd->user_callback != NULL)
{ {
// Reuse existing command (high-level clipping may have discarded vertices submitted earlier) AddDrawCmd();
// FIXME-OPT: Possibly even reuse previous command. current_cmd = &commands.back();
current_cmd->clip_rect = clip_rect; }
current_cmd->user_callback = callback;
current_cmd->user_callback_data = callback_data;
// Force a new command after us
// We function this way so that the most common calls (AddLine, AddRect..) always have a command to add to without doing any check.
AddDrawCmd();
}
void ImDrawList::UpdateClipRect()
{
ImDrawCmd* current_cmd = commands.empty() ? NULL : &commands.back();
if (!current_cmd || (current_cmd->vtx_count != 0) || current_cmd->user_callback != NULL)
{
AddDrawCmd();
} }
else else
{ {
ImDrawCmd draw_cmd; current_cmd->clip_rect = clip_rect_stack.empty() ? GNullClipRect : clip_rect_stack.back();
draw_cmd.vtx_count = 0;
draw_cmd.clip_rect = clip_rect;
draw_cmd.texture_id = texture_id_stack.back();
commands.push_back(draw_cmd);
} }
} }
void ImDrawList::PushClipRect(const ImVec4& clip_rect) void ImDrawList::PushClipRect(const ImVec4& clip_rect)
{ {
clip_rect_stack.push_back(clip_rect); clip_rect_stack.push_back(clip_rect);
SetClipRect(clip_rect); UpdateClipRect();
} }
void ImDrawList::PopClipRect() void ImDrawList::PopClipRect()
{ {
IM_ASSERT(clip_rect_stack.size() > 0); IM_ASSERT(clip_rect_stack.size() > 0);
clip_rect_stack.pop_back(); clip_rect_stack.pop_back();
const ImVec4 clip_rect = clip_rect_stack.empty() ? GNullClipRect : clip_rect_stack.back(); UpdateClipRect();
SetClipRect(clip_rect);
} }
void ImDrawList::SetTextureID(const ImTextureID& texture_id) void ImDrawList::UpdateTextureID()
{ {
ImDrawCmd* current_cmd = commands.empty() ? NULL : &commands.back(); ImDrawCmd* current_cmd = commands.empty() ? NULL : &commands.back();
if (current_cmd && (current_cmd->vtx_count == 0 || current_cmd->texture_id == texture_id)) const ImTextureID texture_id = texture_id_stack.empty() ? NULL : texture_id_stack.back();
if (!current_cmd || (current_cmd->vtx_count != 0 && current_cmd->texture_id != texture_id) || current_cmd->user_callback != NULL)
{ {
// Reuse existing command AddDrawCmd();
// FIXME-OPT: Possibly even reuse previous command.
current_cmd->texture_id = texture_id;
} }
else else
{ {
ImDrawCmd draw_cmd; current_cmd->texture_id = texture_id;
draw_cmd.vtx_count = 0;
draw_cmd.clip_rect = clip_rect_stack.empty() ? GNullClipRect: clip_rect_stack.back();
draw_cmd.texture_id = texture_id;
commands.push_back(draw_cmd);
} }
} }
void ImDrawList::PushTextureID(const ImTextureID& texture_id) void ImDrawList::PushTextureID(const ImTextureID& texture_id)
{ {
texture_id_stack.push_back(texture_id); texture_id_stack.push_back(texture_id);
SetTextureID(texture_id); UpdateTextureID();
} }
void ImDrawList::PopTextureID() void ImDrawList::PopTextureID()
{ {
IM_ASSERT(texture_id_stack.size() > 0); IM_ASSERT(texture_id_stack.size() > 0);
texture_id_stack.pop_back(); texture_id_stack.pop_back();
const ImTextureID texture_id = texture_id_stack.empty() ? NULL : texture_id_stack.back(); UpdateTextureID();
SetTextureID(texture_id);
} }
void ImDrawList::ReserveVertices(unsigned int vtx_count) void ImDrawList::ReserveVertices(unsigned int vtx_count)
@ -6143,6 +6146,7 @@ void ImDrawList::AddVtxUV(const ImVec2& pos, ImU32 col, const ImVec2& uv)
vtx_write++; vtx_write++;
} }
// NB: memory should be reserved for 6 vertices by the caller.
void ImDrawList::AddVtxLine(const ImVec2& a, const ImVec2& b, ImU32 col) void ImDrawList::AddVtxLine(const ImVec2& a, const ImVec2& b, ImU32 col)
{ {
const float length = sqrtf(ImLengthSqr(b - a)); const float length = sqrtf(ImLengthSqr(b - a));

54
imgui.h
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@ -6,6 +6,7 @@
#pragma once #pragma once
struct ImDrawCmd;
struct ImDrawList; struct ImDrawList;
struct ImFont; struct ImFont;
struct ImFontAtlas; struct ImFontAtlas;
@ -693,19 +694,32 @@ struct ImGuiTextEditCallbackData
//----------------------------------------------------------------------------- //-----------------------------------------------------------------------------
// Draw List // Draw List
// Hold a series of drawing commands. The user provides a renderer for ImDrawList // Hold a series of drawing commands. The user provides a renderer for ImDrawList.
//----------------------------------------------------------------------------- //-----------------------------------------------------------------------------
// Typically, One ImDrawCmd = One GPU draw call // Draw callbacks for advanced uses.
// NB- You most likely DO NOT need to care about draw callbacks just to create your own widget or customized UI rendering (you can poke into the draw list for that)
// Draw callback are useful for example if you want to render a complex 3D scene inside a UI element.
// The expected behavior from your rendering loop is:
// if (cmd.user_callback != NULL)
// cmd.user_callback(parent_list, cmd);
// else
// RenderTriangles()
// It is up to you to decide if your rendering loop or the callback should be responsible for backup/restoring rendering state.
typedef void (*ImDrawCallback)(const ImDrawList* parent_list, const ImDrawCmd* cmd);
// Typically, 1 command = 1 gpu draw call
struct ImDrawCmd struct ImDrawCmd
{ {
unsigned int vtx_count; // Number of vertices (multiple of 3) to be drawn. The vertices are stored in the callee ImDrawList's vtx_buffer[] array unsigned int vtx_count; // Number of vertices (multiple of 3) to be drawn as triangles. The vertices are stored in the callee ImDrawList's vtx_buffer[] array.
ImVec4 clip_rect; // Clipping rectangle (x1, y1, x2, y2) ImVec4 clip_rect; // Clipping rectangle (x1, y1, x2, y2)
ImTextureID texture_id; // Copy of user-provided 'TexID' from ImFont or passed to Image*() functions. Ignore if not using images or multiple fonts ImTextureID texture_id; // User-provided texture ID. Set by user in ImfontAtlas::SetTexID() for fonts or passed to Image*() functions. Ignore if never using images or multiple fonts atlas.
ImDrawCallback user_callback; // If != NULL, call the function instead of rendering the vertices. vtx_count will be 0. clip_rect and texture_id will be set normally.
void* user_callback_data; // The draw callback code can access this.
}; };
// Vertex layout
#ifndef IMGUI_OVERRIDE_DRAWVERT_STRUCT_LAYOUT #ifndef IMGUI_OVERRIDE_DRAWVERT_STRUCT_LAYOUT
// Default vertex layout
struct ImDrawVert struct ImDrawVert
{ {
ImVec2 pos; ImVec2 pos;
@ -728,28 +742,20 @@ IMGUI_OVERRIDE_DRAWVERT_STRUCT_LAYOUT;
struct ImDrawList struct ImDrawList
{ {
// This is what you have to render // This is what you have to render
ImVector<ImDrawCmd> commands; // Commands. Typically 1 command = 1 draw call. ImVector<ImDrawCmd> commands; // Commands. Typically 1 command = 1 gpu draw call.
ImVector<ImDrawVert> vtx_buffer; // Vertex buffer. Each command consume ImDrawCmd::vtx_count of those ImVector<ImDrawVert> vtx_buffer; // Vertex buffer. Each command consume ImDrawCmd::vtx_count of those
// [Internal to ImGui] // [Internal to ImGui]
ImVector<ImVec4> clip_rect_stack; // [internal] ImVector<ImVec4> clip_rect_stack; // [Internal]
ImVector<ImTextureID> texture_id_stack; // [internal] ImVector<ImTextureID> texture_id_stack; // [Internal]
ImDrawVert* vtx_write; // [internal] point within vtx_buffer after each add command (to avoid using the ImVector<> operators too much) ImDrawVert* vtx_write; // [Internal] point within vtx_buffer after each add command (to avoid using the ImVector<> operators too much)
ImDrawList() { Clear(); } ImDrawList() { Clear(); }
IMGUI_API void Clear(); IMGUI_API void Clear();
IMGUI_API void SetClipRect(const ImVec4& clip_rect);
IMGUI_API void PushClipRect(const ImVec4& clip_rect); IMGUI_API void PushClipRect(const ImVec4& clip_rect);
IMGUI_API void PopClipRect(); IMGUI_API void PopClipRect();
IMGUI_API void SetTextureID(const ImTextureID& texture_id);
IMGUI_API void PushTextureID(const ImTextureID& texture_id); IMGUI_API void PushTextureID(const ImTextureID& texture_id);
IMGUI_API void PopTextureID(); IMGUI_API void PopTextureID();
IMGUI_API void ReserveVertices(unsigned int vtx_count);
IMGUI_API void AddVtx(const ImVec2& pos, ImU32 col);
IMGUI_API void AddVtxUV(const ImVec2& pos, ImU32 col, const ImVec2& uv);
IMGUI_API void AddVtxLine(const ImVec2& a, const ImVec2& b, ImU32 col);
IMGUI_API void SplitDrawCmd(); // This is useful if you need to force-create a new draw call (to allow for depending rendering / blending). Otherwise primitives are merged into the same draw-call as much as possible
// Primitives // Primitives
IMGUI_API void AddLine(const ImVec2& a, const ImVec2& b, ImU32 col); IMGUI_API void AddLine(const ImVec2& a, const ImVec2& b, ImU32 col);
@ -761,6 +767,18 @@ struct ImDrawList
IMGUI_API void AddArc(const ImVec2& center, float rad, ImU32 col, int a_min, int a_max, bool tris = false, const ImVec2& third_point_offset = ImVec2(0,0)); IMGUI_API void AddArc(const ImVec2& center, float rad, ImU32 col, int a_min, int a_max, bool tris = false, const ImVec2& third_point_offset = ImVec2(0,0));
IMGUI_API void AddText(ImFont* font, float font_size, const ImVec2& pos, ImU32 col, const char* text_begin, const char* text_end = NULL, float wrap_width = 0.0f); IMGUI_API void AddText(ImFont* font, float font_size, const ImVec2& pos, ImU32 col, const char* text_begin, const char* text_end = NULL, float wrap_width = 0.0f);
IMGUI_API void AddImage(ImTextureID user_texture_id, const ImVec2& a, const ImVec2& b, const ImVec2& uv0, const ImVec2& uv1, ImU32 col = 0xFFFFFFFF); IMGUI_API void AddImage(ImTextureID user_texture_id, const ImVec2& a, const ImVec2& b, const ImVec2& uv0, const ImVec2& uv1, ImU32 col = 0xFFFFFFFF);
// Advanced
IMGUI_API void AddCallback(ImDrawCallback callback, void* callback_data); // Your rendering function must check for 'user_callback' in ImDrawCmd and call the function instead of rendering triangles.
IMGUI_API void AddDrawCmd(); // This is useful if you need to forcefully create a new draw call (to allow for dependent rendering / blending). Otherwise primitives are merged into the same draw-call as much as possible
// Internal helpers
IMGUI_API void ReserveVertices(unsigned int vtx_count);
IMGUI_API void AddVtx(const ImVec2& pos, ImU32 col);
IMGUI_API void AddVtxUV(const ImVec2& pos, ImU32 col, const ImVec2& uv);
IMGUI_API void AddVtxLine(const ImVec2& a, const ImVec2& b, ImU32 col);
IMGUI_API void UpdateClipRect();
IMGUI_API void UpdateTextureID();
}; };
// Load and rasterize multiple TTF fonts into a same texture. // Load and rasterize multiple TTF fonts into a same texture.

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