Render.cpp

/*-----------------------------------------------------------------------------

Render.cpp

2006 Shamus Young

-------------------------------------------------------------------------------

This is the core of the gl rendering functions.  This contains the main
rendering function RenderScene (), which initiates the various
other renders in the other modules.

-----------------------------------------------------------------------------*/

#define RENDER_DISTANCE     2048

#include "precompiled.h"

static	PIXELFORMATDESCRIPTOR pfd = {
	sizeof( PIXELFORMATDESCRIPTOR ),
	1,											  // Version Number
	PFD_DRAW_TO_WINDOW |			// Format Must Support Window
	PFD_SUPPORT_OPENGL |			// Format Must Support OpenGL
	PFD_DOUBLEBUFFER,					// Must Support Double Buffering
	PFD_TYPE_RGBA,						// Request An RGBA Format
	32,										    // Select Our glRgbaDepth
	0, 0, 0, 0, 0, 0,					// glRgbaBits Ignored
	0,											  // No Alpha Buffer
	0,											  // Shift Bit Ignored
	0,											  // Accumulation Buffers
	0, 0, 0, 0,								// Accumulation Bits Ignored
	16,											  // Z-Buffer (Depth Buffer)  bits
	0,											  // Stencil Buffers
	1,											  // Auxiliary Buffers
	PFD_MAIN_PLANE,						// Main Drawing Layer
	0,											  // Reserved
	0, 0, 0										// Layer Masks Ignored
};

static HDC			        hDC;
static HGLRC		        hRC;
static int              render_width;
static int              render_height;
static float            render_aspect;
static unsigned char*   buffer;

/*-----------------------------------------------------------------------------

-----------------------------------------------------------------------------*/

void RenderResize( void )
{

	int     left, top;
	
	if( buffer )
		delete[] buffer;
	render_width = WinWidth();
	render_height = WinHeight();
	left = 0;
	top = 0;
	render_aspect = ( float )render_width / ( float )render_height;
	glViewport( left, top, render_width, render_height );
	glMatrixMode( GL_PROJECTION );
	glLoadIdentity();
	gluPerspective( 45.0f, render_aspect, 0.1f, RENDER_DISTANCE );
	glMatrixMode( GL_MODELVIEW );
	buffer = new unsigned char[WinWidth() * WinHeight() * 4];
	
	
}

/*-----------------------------------------------------------------------------

-----------------------------------------------------------------------------*/

void RenderTerm( void )
{

	if( !hRC )
		return;
	wglDeleteContext( hRC );
	hRC = NULL;
	
}

/*-----------------------------------------------------------------------------

-----------------------------------------------------------------------------*/

void RenderInit( void )
{

	HWND                hWnd;
	unsigned		        PixelFormat;
	
	hWnd = WinHwnd();
	if( !( hDC = GetDC( hWnd ) ) ) {   // Did We Get A Device Context?
		WinPopup( "Can't Create A GL Device Context." );
		return;
	}
	if( !( PixelFormat = ChoosePixelFormat( hDC, &pfd ) ) )	{  // Did Windows Find A Matching Pixel Format?
		WinPopup( "Can't Find A Suitable PixelFormat." );
		return;
	}
	if( !SetPixelFormat( hDC, PixelFormat, &pfd ) )	{ // Are We Able To Set The Pixel Format?
		WinPopup( "Can't Set The PixelFormat." );
		return;
	}
	if( !( hRC = wglCreateContext( hDC ) ) )	{   // Are We Able To Get A Rendering Context?
		WinPopup( "Can't Create A GL Rendering Context." );
		return;
	}
	if( !wglMakeCurrent( hDC, hRC ) )	{ // Try To Activate The Rendering Context
		WinPopup( "Can't Activate The GL Rendering Context." );
		return;
	}
	glViewport( 0, 0, WinWidth(), WinHeight() );
	glClearColor( 0.0f, 0.0f, 0.0f, 1.0f );
	glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT );
	SwapBuffers( hDC );
	RenderResize();
	
}

/*-----------------------------------------------------------------------------

-----------------------------------------------------------------------------*/

void RenderUpdate( void )
{
	vec4	light_vector;
	rgba	light_color;
	rgba	ambient_color;
	rgba	fog_color;
	vec3	pos;
	vec3	angle;
	
	light_vector = WorldLightQuat();
	light_color = WorldLightColor();
	fog_color = WorldFogColor();
	ambient_color = WorldAmbientColor();;
	glViewport( 0, 0, WinWidth(), WinHeight() );
	glHint( GL_PERSPECTIVE_CORRECTION_HINT, GL_NICEST );
	glShadeModel( GL_SMOOTH );
	glCullFace( GL_BACK );
	glDepthFunc( GL_LEQUAL );
	//glEnable (GL_FOG);  //enable this for fog
	glFogi( GL_FOG_MODE, GL_LINEAR );
	glFogf( GL_FOG_START, 484.0f );
	glFogf( GL_FOG_END, 5880.0f );
	glFogfv( GL_FOG_COLOR, &light_color.red );
	glEnable( GL_COLOR_MATERIAL );
	glEnable( GL_DEPTH_TEST );
	glEnable( GL_CULL_FACE );
	glCullFace( GL_BACK );
	glBlendFunc( GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA );
	glPolygonMode( GL_FRONT_AND_BACK, GL_FILL );
	glLoadIdentity();
	pos = CameraPosition();
	angle = CameraAngle();
	glRotatef( angle.x, 1.0f, 0.0f, 0.0f );
	glRotatef( angle.y, 0.0f, 1.0f, 0.0f );
	glRotatef( angle.z, 0.0f, 0.0f, 1.0f );
	glTranslatef( -pos.x, -pos.y, -pos.z );
	//This was part of a failed experiment.  I made a system to allow stuff to
	//fade in over time, like in Grand Theft Auto.  This ius very effective,
	//but since the scene is drawn twice it is quite hard on framerate.
	if( 0 ) {
		glDrawBuffer( GL_AUX0 );
		glFogfv( GL_FOG_COLOR, &fog_color.red );
		glClearColor( 0.0f, 0.0f, 1.0f, 1.0f );
		glClear( GL_DEPTH_BUFFER_BIT );
		EntityRenderFadeIn();
		
		glDrawBuffer( GL_BACK );
		glClearColor( 1.0f, 0.0f, 0.0f, 1.0f );
		glClear( GL_DEPTH_BUFFER_BIT );
		EntityRender();
		
		glEnable( GL_BLEND );
		glDisable( GL_TEXTURE_2D );
		glReadBuffer( GL_AUX0 );
		glDrawBuffer( GL_AUX0 );
		glReadPixels( 0, 0, WinWidth(), WinHeight(), GL_RGBA, GL_UNSIGNED_BYTE, buffer );
		glReadBuffer( GL_BACK );
		glDrawBuffer( GL_BACK );
		glColor4f( 1.0f, 1.0f, 1.0f, 0.1f );
		glPixelTransferf( GL_ALPHA_SCALE, WorldFade() );
		glDisable( GL_FOG );
		glDrawPixels( WinWidth(), WinHeight(), GL_RGBA, GL_UNSIGNED_BYTE, buffer );
		
		glReadBuffer( GL_BACK );
		glDrawBuffer( GL_BACK );
		glPixelTransferf( GL_ALPHA_SCALE, 1.0f );
	} else { //this will just render everything once, with no fancy fade
		glClearColor( 1.0f, 0.0f, 0.0f, 1.0f );
		glClear( GL_DEPTH_BUFFER_BIT );
		EntityRender();
	}
	SwapBuffers( hDC );
	
}