// Copyright (c) 2013- PPSSPP Project.

// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, version 2.0 or later versions.

// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License 2.0 for more details.

// A copy of the GPL 2.0 should have been included with the program.
// If not, see http://www.gnu.org/licenses/

// Official git repository and contact information can be found at
// https://github.com/hrydgard/ppsspp and http://www.ppsspp.org/.

#include "../GPUState.h"
#include "../GLES/VertexDecoder.h"

#include "TransformUnit.h"
#include "Clipper.h"

WorldCoords TransformUnit::ModelToWorld(const ModelCoords& coords)
{
	Mat3x3<float> world_matrix(gstate.worldMatrix);
	return WorldCoords(world_matrix * coords) + Vec3<float>(gstate.worldMatrix[9], gstate.worldMatrix[10], gstate.worldMatrix[11]);
}

ViewCoords TransformUnit::WorldToView(const WorldCoords& coords)
{
	Mat3x3<float> view_matrix(gstate.viewMatrix);
	return ViewCoords(view_matrix * coords) + Vec3<float>(gstate.viewMatrix[9], gstate.viewMatrix[10], gstate.viewMatrix[11]);
}

ClipCoords TransformUnit::ViewToClip(const ViewCoords& coords)
{
	Vec4<float> coords4(coords.x, coords.y, coords.z, 1.0f);
	Mat4x4<float> projection_matrix(gstate.projMatrix);
	return ClipCoords(projection_matrix * coords4);
}

ScreenCoords TransformUnit::ClipToScreen(const ClipCoords& coords)
{
	ScreenCoords ret;
	float vpx1 = getFloat24(gstate.viewportx1);
	float vpx2 = getFloat24(gstate.viewportx2);
	float vpy1 = getFloat24(gstate.viewporty1);
	float vpy2 = getFloat24(gstate.viewporty2);
	float vpz1 = getFloat24(gstate.viewportz1);
	float vpz2 = getFloat24(gstate.viewportz2);
	// TODO: Check for invalid parameters (x2 < x1, etc)
	ret.x = (coords.x * vpx1 / coords.w + vpx2) * 16; // 16 = 0xFFFF / 4095.9375;
	ret.y = (coords.y * vpy1 / coords.w + vpy2) * 16; // 16 = 0xFFFF / 4095.9375;
	ret.z = (coords.z * vpz1 / coords.w + vpz2) * 16; // 16 = 0xFFFF / 4095.9375;
	return ret;
}

DrawingCoords TransformUnit::ScreenToDrawing(const ScreenCoords& coords)
{
	DrawingCoords ret;
	// TODO: What to do when offset > coord?
	ret.x = (((u32)coords.x - (gstate.offsetx&0xffff))/16) & 0x3ff;
	ret.y = (((u32)coords.y - (gstate.offsety&0xffff))/16) & 0x3ff;
	return ret;
}

void TransformUnit::SubmitPrimitive(void* vertices, u32 prim_type, int vertex_count, u32 vertex_type)
{
	// TODO: Cache VertexDecoder objects
	VertexDecoder vdecoder;
	vdecoder.SetVertexType(vertex_type);
	const DecVtxFormat& vtxfmt = vdecoder.GetDecVtxFmt();

	static u8 buf[102400]; // yolo
	vdecoder.DecodeVerts(buf, vertices, 0, vertex_count - 1);

	VertexReader vreader(buf, vtxfmt, vertex_type);

	// We only support triangle lists, for now.
	for (int vtx = 0; vtx < vertex_count; vtx+=3)
	{
		VertexData data[3];

		for (unsigned int i = 0; i < 3; ++i)
		{
			float pos[3];
			vreader.Goto(vtx+i);
			vreader.ReadPos(pos);

			if (gstate.textureMapEnable && vreader.hasUV())
			{
				float uv[2];
				vreader.ReadUV(uv);
				data[i].texturecoords = Vec2<float>(uv[0], uv[1]);
			}

			ModelCoords mcoords(pos[0], pos[1], pos[2]);
			data[i].clippos = ClipCoords(ClipCoords(TransformUnit::ViewToClip(TransformUnit::WorldToView(TransformUnit::ModelToWorld(mcoords)))));
			data[i].drawpos = DrawingCoords(TransformUnit::ScreenToDrawing(TransformUnit::ClipToScreen(data[i].clippos)));
		}

		// TODO: Should do lighting here!

		Clipper::ProcessTriangle(data);
	}
}