/*
** hw_flatvertices.cpp
** Creates flat vertex data for hardware rendering.
**
**---------------------------------------------------------------------------
** Copyright 2010-2020 Christoph Oelckers
** All rights reserved.
**
** Redistribution and use in source and binary forms, with or without
** modification, are permitted provided that the following conditions
** are met:
**
** 1. Redistributions of source code must retain the above copyright
**    notice, this list of conditions and the following disclaimer.
** 2. Redistributions in binary form must reproduce the above copyright
**    notice, this list of conditions and the following disclaimer in the
**    documentation and/or other materials provided with the distribution.
** 3. The name of the author may not be used to endorse or promote products
**    derived from this software without specific prior written permission.
**
** THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
** IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
** OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
** IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
** INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
** NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
** THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
**---------------------------------------------------------------------------
**
*/

#include "c_cvars.h"
#include "flatvertices.h"
#include "v_video.h"
#include "cmdlib.h"
#include "printf.h"
#include "hwrenderer/data/buffers.h"

//==========================================================================
//
//
//
//==========================================================================

FFlatVertexBuffer::FFlatVertexBuffer(int width, int height)
{
	vbo_shadowdata.Resize(NUM_RESERVED);

	// the first quad is reserved for handling coordinates through uniforms.
	vbo_shadowdata[0].Set(0, 0, 0, 0, 0);
	vbo_shadowdata[1].Set(1, 0, 0, 0, 0);
	vbo_shadowdata[2].Set(2, 0, 0, 0, 0);
	vbo_shadowdata[3].Set(3, 0, 0, 0, 0);

	// and the second one for the fullscreen quad used for blend overlays.
	vbo_shadowdata[4].Set(0, 0, 0, 0, 0);
	vbo_shadowdata[5].Set(0, (float)height, 0, 0, 1);
	vbo_shadowdata[6].Set((float)width, 0, 0, 1, 0);
	vbo_shadowdata[7].Set((float)width, (float)height, 0, 1, 1);

	// and this is for the postprocessing copy operation
	vbo_shadowdata[8].Set(-1.0f, -1.0f, 0, 0.0f, 0.0f);
	vbo_shadowdata[9].Set(-1.0f, 1.0f, 0, 0.0f, 1.f);
	vbo_shadowdata[10].Set(1.0f, -1.0f, 0, 1.f, 0.0f);
	vbo_shadowdata[11].Set(1.0f, 1.0f, 0, 1.f, 1.f);

	// The next two are the stencil caps.
	vbo_shadowdata[12].Set(-32767.0f, 32767.0f, -32767.0f, 0, 0);
	vbo_shadowdata[13].Set(-32767.0f, 32767.0f, 32767.0f, 0, 0);
	vbo_shadowdata[14].Set(32767.0f, 32767.0f, 32767.0f, 0, 0);
	vbo_shadowdata[15].Set(32767.0f, 32767.0f, -32767.0f, 0, 0);

	vbo_shadowdata[16].Set(-32767.0f, -32767.0f, -32767.0f, 0, 0);
	vbo_shadowdata[17].Set(-32767.0f, -32767.0f, 32767.0f, 0, 0);
	vbo_shadowdata[18].Set(32767.0f, -32767.0f, 32767.0f, 0, 0);
	vbo_shadowdata[19].Set(32767.0f, -32767.0f, -32767.0f, 0, 0);

	mVertexBuffer = screen->CreateVertexBuffer();
	mIndexBuffer = screen->CreateIndexBuffer();

	unsigned int bytesize = BUFFER_SIZE * sizeof(FFlatVertex);
	mVertexBuffer->SetData(bytesize, nullptr, false);

	static const FVertexBufferAttribute format[] = {
		{ 0, VATTR_VERTEX, VFmt_Float3, (int)myoffsetof(FFlatVertex, x) },
		{ 0, VATTR_TEXCOORD, VFmt_Float2, (int)myoffsetof(FFlatVertex, u) }
	};
	mVertexBuffer->SetFormat(1, 2, sizeof(FFlatVertex), format);

	mIndex = mCurIndex = NUM_RESERVED;
	mNumReserved = NUM_RESERVED;
	Copy(0, NUM_RESERVED);
}

//==========================================================================
//
//
//
//==========================================================================

FFlatVertexBuffer::~FFlatVertexBuffer()
{
	delete mIndexBuffer;
	delete mVertexBuffer;
	mIndexBuffer = nullptr;
	mVertexBuffer = nullptr;
}

//==========================================================================
//
//
//
//==========================================================================

void FFlatVertexBuffer::OutputResized(int width, int height)
{
	vbo_shadowdata[4].Set(0, 0, 0, 0, 0);
	vbo_shadowdata[5].Set(0, (float)height, 0, 0, 1);
	vbo_shadowdata[6].Set((float)width, 0, 0, 1, 0);
	vbo_shadowdata[7].Set((float)width, (float)height, 0, 1, 1);
	Copy(4, 4);
}

//==========================================================================
//
//
//
//==========================================================================

std::pair<FFlatVertex *, unsigned int> FFlatVertexBuffer::AllocVertices(unsigned int count)
{
	FFlatVertex *p = GetBuffer();
	auto index = mCurIndex.fetch_add(count);
	auto offset = index;
	if (index + count >= BUFFER_SIZE_TO_USE)
	{
		// If a single scene needs 2'000'000 vertices there must be something very wrong. 
		I_FatalError("Out of vertex memory. Tried to allocate more than %u vertices for a single frame", index + count);
	}
	return std::make_pair(p, index);
}

//==========================================================================
//
//
//
//==========================================================================

void FFlatVertexBuffer::Copy(int start, int count)
{
	Map();
	memcpy(GetBuffer(start), &vbo_shadowdata[0], count * sizeof(FFlatVertex));
	Unmap();
}