bgfx metal bad performance patch

gistfile1.txt

/*
 * Copyright 2011-2017 Branimir Karadzic. All rights reserved.
 * License: https://github.com/bkaradzic/bgfx#license-bsd-2-clause
 */

#include "common.h"
#include "bgfx_utils.h"
#include "imgui/imgui.h"

namespace
{

struct PosColorVertex
{
	float m_x;
	float m_y;
	float m_z;
	uint32_t m_abgr;

	static void init()
	{
		ms_decl
			.begin()
			.add(bgfx::Attrib::Position, 3, bgfx::AttribType::Float)
			.add(bgfx::Attrib::Color0,   4, bgfx::AttribType::Uint8, true)
			.end();
	};

	static bgfx::VertexDecl ms_decl;
};

bgfx::VertexDecl PosColorVertex::ms_decl;

static PosColorVertex s_cubeVertices[] =
{
	{-2.0f,  1.0f,  1.0f, 0x1f000000 },
	{ 2.0f,  1.0f,  1.0f, 0x1f0000ff },
	{-2.0f, -1.0f,  1.0f, 0x1f00ff00 },
	{ 2.0f, -1.0f,  1.0f, 0x1f00ffff },
	{-2.0f,  1.0f, -1.0f, 0x1fff0000 },
	{ 2.0f,  1.0f, -1.0f, 0x1fff00ff },
	{-2.0f, -1.0f, -1.0f, 0x1fffff00 },
	{ 2.0f, -1.0f, -1.0f, 0x1fffffff },
};

static const uint16_t s_cubeTriStrip[] =
{
	0, 1, 2,
	3,
	7,
	1,
	5,
	0,
	4,
	2,
	6,
	7,
	4,
	5,
};

class ExampleCubes : public entry::AppI
{
public:
	ExampleCubes(const char* _name, const char* _description)
		: entry::AppI(_name, _description)
	{
	}

	void init(int32_t _argc, const char* const* _argv, uint32_t _width, uint32_t _height) override
	{
		Args args(_argc, _argv);

		m_debug  = BGFX_DEBUG_NONE;
		m_reset  = BGFX_RESET_VSYNC;
  
		// bgfx::init(bgfx::RendererType::OpenGLES); // Uncomment for OpenGLES -> be sure to comment line 17 in entry_ios.mm
		bgfx::init(bgfx::RendererType::Metal); // Uncomment for Metal -> be sure to uncomment line 17 in entry_ios.mm
		bgfx::reset(m_width, m_height, m_reset);

		// Enable debug text.
		bgfx::setDebug(m_debug);

		// Set view 0 clear state.
		bgfx::setViewClear(0
				, BGFX_CLEAR_COLOR|BGFX_CLEAR_DEPTH
				, 0x303030ff
				, 1.0f
				, 0
				);

		// Create vertex stream declaration.
		PosColorVertex::init();

		// Create static vertex buffer.
		m_vbh = bgfx::createVertexBuffer(
				// Static data can be passed with bgfx::makeRef
				bgfx::makeRef(s_cubeVertices, sizeof(s_cubeVertices) )
				, PosColorVertex::ms_decl
				);

		// Create static index buffer.
		m_ibh = bgfx::createIndexBuffer(
				// Static data can be passed with bgfx::makeRef
				bgfx::makeRef(s_cubeTriStrip, sizeof(s_cubeTriStrip) )
				);

		// Create program from shaders.
		m_program = loadProgram("vs_cubes", "fs_cubes");

		m_timeOffset = bx::getHPCounter();

		imguiCreate();
	}

	virtual int shutdown() override
	{
		imguiDestroy();

		// Cleanup.
		bgfx::destroy(m_ibh);
		bgfx::destroy(m_vbh);
		bgfx::destroy(m_program);

		// Shutdown bgfx.
		bgfx::shutdown();

		return 0;
	}

	bool update() override
	{
		if (!entry::processEvents(m_width, m_height, m_debug, m_reset, &m_mouseState) )
		{
			float at[3]  = { 0.0f, 0.0f,   0.0f };
			float eye[3] = { 0.0f, 0.0f, -2.0f };

            float view[16];
            bx::mtxLookAt(view, eye, at);

            float proj[16];
            bx::mtxProj(proj, 60.0f, float(m_width)/float(m_height), 0.1f, 100.0f, bgfx::getCaps()->homogeneousDepth);
            bgfx::setViewTransform(0, view, proj);

            // Set view 0 default viewport.
            bgfx::setViewRect(0, 0, 0, uint16_t(m_width), uint16_t(m_height) );

			// This dummy draw call is here to make sure that view 0 is cleared
			// if no other draw calls are submitted to view 0.
            bgfx::touch(0);

            for(int pass = 0;pass<16;++pass) {
                float mtx[16];
                bx::mtxIdentity(mtx);

                // Set model matrix for rendering.
                bgfx::setTransform(mtx);

                // Set vertex and index buffer.
                bgfx::setVertexBuffer(0, m_vbh);
                bgfx::setIndexBuffer(m_ibh);

                // Set render states.
                bgfx::setState(0
                    | BGFX_STATE_RGB_WRITE       
                    | BGFX_STATE_ALPHA_WRITE     
                    | BGFX_STATE_DEPTH_TEST_LESS 
                    | BGFX_STATE_CULL_CW
                    | BGFX_STATE_PT_TRISTRIP
                    | BGFX_STATE_BLEND_FUNC(BGFX_STATE_BLEND_SRC_ALPHA, BGFX_STATE_BLEND_INV_SRC_ALPHA)
                    );

                // Submit primitive for rendering to view 0.
                bgfx::submit(0, m_program);
            }
            
			// Advance to next frame. Rendering thread will be kicked to
			// process submitted rendering primitives.
			bgfx::frame();

			return true;
		}

		return false;
	}

	entry::MouseState m_mouseState;

	uint32_t m_width;
	uint32_t m_height;
	uint32_t m_debug;
	uint32_t m_reset;
	bgfx::VertexBufferHandle m_vbh;
	bgfx::IndexBufferHandle m_ibh;
	bgfx::ProgramHandle m_program;
	int64_t m_timeOffset;
};

} // namespace

ENTRY_IMPLEMENT_MAIN(ExampleCubes, "01-cube", "Rendering simple static mesh.");