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

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ocornut
2015-01-31 15:24:55 +00:00
parent 82666cdc57
commit 2ecc285919
2 changed files with 71 additions and 49 deletions
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54
imgui.h
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@ -6,6 +6,7 @@
#pragma once
struct ImDrawCmd;
struct ImDrawList;
struct ImFont;
struct ImFontAtlas;
@ -693,19 +694,32 @@ struct ImGuiTextEditCallbackData
//-----------------------------------------------------------------------------
// 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
{
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
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
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)
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
// Default vertex layout
struct ImDrawVert
{
ImVec2 pos;
@ -728,28 +742,20 @@ IMGUI_OVERRIDE_DRAWVERT_STRUCT_LAYOUT;
struct ImDrawList
{
// 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
// [Internal to ImGui]
ImVector<ImVec4> clip_rect_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)
ImVector<ImVec4> clip_rect_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)
ImDrawList() { Clear(); }
IMGUI_API void Clear();
IMGUI_API void SetClipRect(const ImVec4& clip_rect);
IMGUI_API void PushClipRect(const ImVec4& clip_rect);
IMGUI_API void PopClipRect();
IMGUI_API void SetTextureID(const ImTextureID& texture_id);
IMGUI_API void PushTextureID(const ImTextureID& texture_id);
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
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 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);
// 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.