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Xenia-Canary/src/xenia/ui/immediate_drawer.h

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/**
******************************************************************************
* Xenia : Xbox 360 Emulator Research Project *
******************************************************************************
* Copyright 2015 Ben Vanik. All rights reserved. *
* Released under the BSD license - see LICENSE in the root for more details. *
******************************************************************************
*/
#ifndef XENIA_UI_IMMEDIATE_DRAWER_H_
#define XENIA_UI_IMMEDIATE_DRAWER_H_
#include <memory>
namespace xe {
namespace ui {
class GraphicsContext;
// Describes the filter applied when sampling textures.
enum class ImmediateTextureFilter {
kNearest,
kLinear,
};
// Simple texture compatible with the immediate renderer.
class ImmediateTexture {
public:
virtual ~ImmediateTexture() = default;
// Texture width, in pixels.
uint32_t width;
// Texture height, in pixels.
uint32_t height;
// Internal handle. Can be passed with the ImmediateDrawBatch.
uintptr_t handle;
protected:
ImmediateTexture(uint32_t width, uint32_t height)
: width(width), height(height) {}
};
// Describes the primitive type used by a draw call.
enum class ImmediatePrimitiveType {
kLines,
kTriangles,
};
// Simple vertex used by the immediate mode drawer.
// To avoid translations, this matches both imgui and elemental-forms vertices:
// ImDrawVert
// el::graphics::Renderer::Vertex
struct ImmediateVertex {
float x, y;
float u, v;
uint32_t color;
};
// All parameters required to draw an immediate-mode batch of vertices.
struct ImmediateDrawBatch {
// Vertices to draw.
const ImmediateVertex* vertices = nullptr;
int vertex_count = 0;
// Optional index buffer indices.
const uint16_t* indices = nullptr;
int index_count = 0;
};
struct ImmediateDraw {
// Primitive type the vertices/indices represent.
ImmediatePrimitiveType primitive_type = ImmediatePrimitiveType::kTriangles;
// Total number of elements to draw.
int count = 0;
// Starting offset in the index buffer.
int index_offset = 0;
// Base vertex of elements, if using an index buffer.
int base_vertex = 0;
// Texture used when drawing, or nullptr if color only.
// This is most commonly the handle of an ImmediateTexture.
uintptr_t texture_handle = 0;
// Any samples outside of [0-1] on uv will be ignored.
bool restrict_texture_samples = false;
// True to enable scissoring using the region defined by scissor_rect.
bool scissor = false;
// Scissoring region in framebuffer pixels as (x, y, w, h).
int scissor_rect[4] = {0};
// Blends this draw with the background depending on its alpha (if true).
bool alpha_blend = true;
};
class ImmediateDrawer {
public:
virtual ~ImmediateDrawer() = default;
// Creates a new texture with the given attributes and optionally updates
// initial data.
virtual std::unique_ptr<ImmediateTexture> CreateTexture(
uint32_t width, uint32_t height, ImmediateTextureFilter filter,
bool repeat, const uint8_t* data = nullptr) = 0;
// Uploads data to the given texture, replacing the current contents.
virtual void UpdateTexture(ImmediateTexture* texture,
const uint8_t* data) = 0;
// Begins drawing in immediate mode using the given projection matrix.
virtual void Begin(int render_target_width, int render_target_height) = 0;
// Starts a draw batch.
virtual void BeginDrawBatch(const ImmediateDrawBatch& batch) = 0;
// Draws one set of a batch.
virtual void Draw(const ImmediateDraw& draw) = 0;
// Ends a draw batch.
virtual void EndDrawBatch() = 0;
// Ends drawing in immediate mode and flushes contents.
virtual void End() = 0;
protected:
ImmediateDrawer(GraphicsContext* graphics_context)
: graphics_context_(graphics_context) {}
GraphicsContext* graphics_context_ = nullptr;
};
} // namespace ui
} // namespace xe
#endif // XENIA_UI_IMMEDIATE_DRAWER_H_