// Copyright (c) 2012- 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 <algorithm>
#include "Common/Common.h"
#include "GPU/Common/FramebufferCommon.h"
#include "GPU/GPUState.h"

FramebufferManagerCommon::FramebufferManagerCommon() :
	displayFramebufPtr_(0),
	displayStride_(0),
	displayFormat_(GE_FORMAT_565),
	displayFramebuf_(0),
	prevDisplayFramebuf_(0),
	prevPrevDisplayFramebuf_(0),
	frameLastFramebufUsed_(0),
	currentRenderVfb_(0),
	framebufRangeEnd_(0) {
}

FramebufferManagerCommon::~FramebufferManagerCommon() {
}

void FramebufferManagerCommon::SetDisplayFramebuffer(u32 framebuf, u32 stride, GEBufferFormat format) {
	displayFramebufPtr_ = framebuf;
	displayStride_ = stride;
	displayFormat_ = format;
}

// Heuristics to figure out the size of FBO to create.
void FramebufferManagerCommon::EstimateDrawingSize(int &drawing_width, int &drawing_height) {
	static const int MAX_FRAMEBUF_HEIGHT = 512;
	const int viewport_width = (int) gstate.getViewportX1();
	const int viewport_height = (int) gstate.getViewportY1();
	const int region_width = gstate.getRegionX2() + 1;
	const int region_height = gstate.getRegionY2() + 1;
	const int scissor_width = gstate.getScissorX2() + 1;
	const int scissor_height = gstate.getScissorY2() + 1;
	const int fb_stride = std::max(gstate.FrameBufStride(), 4);

	// Games don't always set any of these.  Take the greatest parameter that looks valid based on stride.
	if (viewport_width > 4 && viewport_width <= fb_stride) {
		drawing_width = viewport_width;
		drawing_height = viewport_height;
		// Some games specify a viewport with 0.5, but don't have VRAM for 273.  480x272 is the buffer size.
		if (viewport_width == 481 && region_width == 480 && viewport_height == 273 && region_height == 272) {
			drawing_width = 480;
			drawing_height = 272;
		}
		// Sometimes region is set larger than the VRAM for the framebuffer.
		if (region_width <= fb_stride && region_width > drawing_width && region_height <= MAX_FRAMEBUF_HEIGHT) {
			drawing_width = region_width;
			drawing_height = std::max(drawing_height, region_height);
		}
		// Scissor is often set to a subsection of the framebuffer, so we pay the least attention to it.
		if (scissor_width <= fb_stride && scissor_width > drawing_width && scissor_height <= MAX_FRAMEBUF_HEIGHT) {
			drawing_width = scissor_width;
			drawing_height = std::max(drawing_height, scissor_height);
		}
	} else {
		// If viewport wasn't valid, let's just take the greatest anything regardless of stride.
		drawing_width = std::min(std::max(region_width, scissor_width), fb_stride);
		drawing_height = std::max(region_height, scissor_height);
	}

	// Assume no buffer is > 512 tall, it couldn't be textured or displayed fully if so.
	if (drawing_height >= MAX_FRAMEBUF_HEIGHT) {
		if (region_height < MAX_FRAMEBUF_HEIGHT) {
			drawing_height = region_height;
		} else if (scissor_height < MAX_FRAMEBUF_HEIGHT) {
			drawing_height = scissor_height;
		}
	}

	if (viewport_width != region_width) {
		// The majority of the time, these are equal.  If not, let's check what we know.
		const u32 fb_address = gstate.getFrameBufAddress();
		u32 nearest_address = 0xFFFFFFFF;
		for (size_t i = 0; i < vfbs_.size(); ++i) {
			const u32 other_address = vfbs_[i]->fb_address | 0x44000000;
			if (other_address > fb_address && other_address < nearest_address) {
				nearest_address = other_address;
			}
		}

		// Unless the game is using overlapping buffers, the next buffer should be far enough away.
		// This catches some cases where we can know this.
		// Hmm.  The problem is that we could only catch it for the first of two buffers...
		const u32 bpp = gstate.FrameBufFormat() == GE_FORMAT_8888 ? 4 : 2;
		int avail_height = (nearest_address - fb_address) / (fb_stride * bpp);
		if (avail_height < drawing_height && avail_height == region_height) {
			drawing_width = std::min(region_width, fb_stride);
			drawing_height = avail_height;
		}

		// Some games draw buffers interleaved, with a high stride/region/scissor but default viewport.
		if (fb_stride == 1024 && region_width == 1024 && scissor_width == 1024) {
			drawing_width = 1024;
		}
	}

	DEBUG_LOG(G3D, "Est: %08x V: %ix%i, R: %ix%i, S: %ix%i, STR: %i, THR:%i, Z:%08x = %ix%i", gstate.getFrameBufAddress(), viewport_width,viewport_height, region_width, region_height, scissor_width, scissor_height, fb_stride, gstate.isModeThrough(), gstate.isDepthWriteEnabled() ? gstate.getDepthBufAddress() : 0, drawing_width, drawing_height);
}