/*
===========================================================================
Copyright (C) 1999-2005 Id Software, Inc.

This file is part of Quake III Arena source code.

Quake III Arena source code 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; either version 2 of the License,
or (at your option) any later version.

Quake III Arena source code 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 for more details.

You should have received a copy of the GNU General Public License
along with Quake III Arena source code; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
===========================================================================
*/
#include "tr_local.h"


static void R_IssueRenderCommands()
{
	renderCommandList_t* cmdList = &backEndData->commands;

	// add an end-of-list command
	*(int *)(cmdList->cmds + cmdList->used) = RC_END_OF_LIST;

	// clear it out, in case this is a sync and not a buffer flip
	cmdList->used = 0;

    RB_ExecuteRenderCommands( cmdList->cmds );
}


/*
====================
R_SyncRenderThread

Issue any pending commands and wait for them to complete.
After exiting, the render thread will have completed its work
and will remain idle and the main thread is free to issue
OpenGL calls until R_IssueRenderCommands is called.
====================
*/
void R_SyncRenderThread( void ) {
	if ( !tr.registered ) {
		return;
	}
	R_IssueRenderCommands();
}

/*
============
R_GetCommandBuffer

make sure there is enough command space, waiting on the
render thread if needed.
============
*/
void *R_GetCommandBuffer( int bytes ) {
	renderCommandList_t	*cmdList;

	cmdList = &backEndData->commands;
	bytes = PAD(bytes, sizeof(void *));

	// always leave room for the end of list command
	if ( cmdList->used + bytes + 4 > MAX_RENDER_COMMANDS ) {
		if ( bytes > MAX_RENDER_COMMANDS - 4 ) {
			ri.Error( ERR_FATAL, "R_GetCommandBuffer: bad size %i", bytes );
		}
		// if we run out of room, just start dropping commands
		return NULL;
	}

	cmdList->used += bytes;

	return cmdList->cmds + cmdList->used - bytes;
}


// technically, all commands should probably check tr.registered
// but realistically, only begin+end frame really need to
#define R_CMD(T, ID) T* cmd = (T*)R_GetCommandBuffer( sizeof(T) ); if (!cmd) return; cmd->commandId = ID;


void R_AddDrawSurfCmd( drawSurf_t* drawSurfs, int numDrawSurfs )
{
	R_CMD( drawSurfsCommand_t, RC_DRAW_SURFS );

	cmd->drawSurfs = drawSurfs;
	cmd->numDrawSurfs = numDrawSurfs;

	cmd->refdef = tr.refdef;
	cmd->viewParms = tr.viewParms;
}


// passing NULL will set the color to white

void RE_SetColor( const float* rgba )
{
	R_CMD( setColorCommand_t, RC_SET_COLOR );

	if ( !rgba )
		rgba = colorWhite;

	cmd->color[0] = rgba[0];
	cmd->color[1] = rgba[1];
	cmd->color[2] = rgba[2];
	cmd->color[3] = rgba[3];
}


void RE_StretchPic( float x, float y, float w, float h, float s1, float t1, float s2, float t2, qhandle_t hShader )
{
	R_CMD( stretchPicCommand_t, RC_STRETCH_PIC );

	cmd->shader = R_GetShaderByHandle( hShader );
	cmd->x = x;
	cmd->y = y;
	cmd->w = w;
	cmd->h = h;
	cmd->s1 = s1;
	cmd->t1 = t1;
	cmd->s2 = s2;
	cmd->t2 = t2;
}


void RE_DrawTriangle( float x0, float y0, float x1, float y1, float x2, float y2, float s0, float t0, float s1, float t1, float s2, float t2, qhandle_t hShader )
{
	R_CMD( triangleCommand_t, RC_TRIANGLE );

	cmd->shader = R_GetShaderByHandle( hShader );
	cmd->x0 = x0;
	cmd->y0 = y0;
	cmd->x1 = x1;
	cmd->y1 = y1;
	cmd->x2 = x2;
	cmd->y2 = y2;
	cmd->s0 = s0;
	cmd->t0 = t0;
	cmd->s1 = s1;
	cmd->t1 = t1;
	cmd->s2 = s2;
	cmd->t2 = t2;
}


// if running in stereo, RE_BeginFrame will be called twice for each RE_EndFrame

void RE_BeginFrame( stereoFrame_t stereoFrame )
{
	if (!tr.registered)
		return;

	glState.finishCalled = qfalse;

	tr.frameCount++;
	tr.frameSceneNum = 0;

	//
	// do overdraw measurement
	//
	if ( r_measureOverdraw->integer )
	{
		if ( glConfig.stencilBits < 4 )
		{
			ri.Printf( PRINT_ALL, "Warning: not enough stencil bits to measure overdraw: %d\n", glConfig.stencilBits );
			ri.Cvar_Set( "r_measureOverdraw", "0" );
			r_measureOverdraw->modified = qfalse;
		}
		else
		{
			R_SyncRenderThread();
			qglEnable( GL_STENCIL_TEST );
			qglStencilMask( ~0U );
			qglClearStencil( 0U );
			qglStencilFunc( GL_ALWAYS, 0U, ~0U );
			qglStencilOp( GL_KEEP, GL_INCR, GL_INCR );
		}
		r_measureOverdraw->modified = qfalse;
	}
	else
	{
		// this is only reached if it was on and is now off
		if ( r_measureOverdraw->modified ) {
			R_SyncRenderThread();
			qglDisable( GL_STENCIL_TEST );
		}
		r_measureOverdraw->modified = qfalse;
	}

	//
	// texturemode stuff
	//
	if ( r_textureMode->modified ) {
		R_SyncRenderThread();
		GL_TextureMode( r_textureMode->string );
		r_textureMode->modified = qfalse;
	}

	//
	// gamma stuff
	//
	if ( r_gamma->modified ) {
		r_gamma->modified = qfalse;
		R_SyncRenderThread();
		R_SetColorMappings();
	}

	// check for errors
	if ( !r_ignoreGLErrors->integer ) {
		int err;
		R_SyncRenderThread();
		if ( ( err = qglGetError() ) != GL_NO_ERROR ) {
			ri.Error( ERR_FATAL, "RE_BeginFrame() - glGetError() failed (0x%x)!\n", err );
		}
	}

	//
	// delayed screenshot
	//
	if ( r_delayedScreenshotPending ) {
		r_delayedScreenshotFrame++;
		if ( r_delayedScreenshotFrame >= 2 ) {
			R_CMD( screenshotCommand_t, RC_SCREENSHOT );
			*cmd = r_delayedScreenshot;
			r_delayedScreenshotPending = qfalse;
			r_delayedScreenshotFrame = 0;
		}
	}

	//
	// draw buffer stuff
	//
	R_CMD( beginFrameCommand_t, RC_BEGIN_FRAME );
}


void RE_EndFrame( int* pcFE, int* pc2D, int* pc3D, qbool render )
{
	if (!tr.registered)
		return;

	if (tr.maxFPS > 0) {
		if (Sys_Milliseconds() < tr.nextFrameTimeMS)
			return;
		tr.nextFrameTimeMS += 1000 / tr.maxFPS;
	}

	qbool delayScreenshot = qfalse;
	if ( !render && r_delayedScreenshotPending )
		render = qtrue;

	if ( !render ) {
		screenshotCommand_t* ssCmd = (screenshotCommand_t*)RB_FindRenderCommand( RC_SCREENSHOT );

		if ( ssCmd )
			render = qtrue;

		if ( ssCmd && !ssCmd->delayed ) {
			// save and remove the command so we can push it back after the frame's done
			r_delayedScreenshot = *ssCmd;
			r_delayedScreenshot.delayed = qtrue;
			RB_RemoveRenderCommand( ssCmd, sizeof(screenshotCommand_t) );
			delayScreenshot = qtrue;
		}
	}

	if ( render ) {
		R_CMD( swapBuffersCommand_t, RC_SWAP_BUFFERS );
		if ( delayScreenshot ) {
			R_CMD( screenshotCommand_t, RC_SCREENSHOT );
			*cmd = r_delayedScreenshot;
		}
	} else {
		R_ClearFrame();
	}

	R_IssueRenderCommands();

	R_ClearFrame();

	if (pcFE)
		Com_Memcpy( pcFE, &tr.pc, sizeof( tr.pc ) );

	if (pc2D)
		Com_Memcpy( pc2D, &backEnd.pc2D, sizeof( backEnd.pc2D ) );

	if (pc3D)
		Com_Memcpy( pc3D, &backEnd.pc3D, sizeof( backEnd.pc3D ) );

	Com_Memset( &tr.pc, 0, sizeof( tr.pc ) );
	Com_Memset( &backEnd.pc2D, 0, sizeof( backEnd.pc2D ) );
	Com_Memset( &backEnd.pc3D, 0, sizeof( backEnd.pc3D ) );
}


void RE_TakeVideoFrame( int width, int height, byte *captureBuffer, byte *encodeBuffer, qbool motionJpeg )
{
	R_CMD( videoFrameCommand_t, RC_VIDEOFRAME );

	cmd->width = width;
	cmd->height = height;
	cmd->captureBuffer = captureBuffer;
	cmd->encodeBuffer = encodeBuffer;
	cmd->motionJpeg = motionJpeg;
}