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

	nehe lesson 3 port to GX by WinterMute

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

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <malloc.h>
#include <math.h>
#include <gccore.h>
#include <wiiuse/wpad.h>
 
#define DEFAULT_FIFO_SIZE	(256*1024)
 
static void *frameBuffer[2] = { NULL, NULL};
GXRModeObj *rmode;

//---------------------------------------------------------------------------------
int main( int argc, char **argv ){
//---------------------------------------------------------------------------------
	f32 yscale;

	u32 xfbHeight;

	Mtx view;
	Mtx44 perspective;
	Mtx model, modelview;

    int scissor_mode = 0;

	u32	fb = 0; 	// initial framebuffer index
	GXColor background = {0, 0, 0, 0xff};


	// init the vi.
	VIDEO_Init();
	WPAD_Init();
 
	rmode = VIDEO_GetPreferredMode(NULL);
	
	// allocate 2 framebuffers for double buffering
	frameBuffer[0] = MEM_K0_TO_K1(SYS_AllocateFramebuffer(rmode));
	frameBuffer[1] = MEM_K0_TO_K1(SYS_AllocateFramebuffer(rmode));

	VIDEO_Configure(rmode);
	VIDEO_SetNextFramebuffer(frameBuffer[fb]);
	VIDEO_SetBlack(FALSE);
	VIDEO_Flush();
	VIDEO_WaitVSync();
	if(rmode->viTVMode&VI_NON_INTERLACE) VIDEO_WaitVSync();

	// setup the fifo and then init the flipper
	void *gp_fifo = NULL;
	gp_fifo = memalign(32,DEFAULT_FIFO_SIZE);
	memset(gp_fifo,0,DEFAULT_FIFO_SIZE);
 
	GX_Init(gp_fifo,DEFAULT_FIFO_SIZE);
 
	// clears the bg to color and clears the z buffer
	GX_SetCopyClear(background, 0x00ffffff);
 
	// other gx setup
	GX_SetViewport(0,0,rmode->fbWidth,rmode->efbHeight,0,1);
	yscale = GX_GetYScaleFactor(rmode->efbHeight,rmode->xfbHeight);
	xfbHeight = GX_SetDispCopyYScale(yscale);
	GX_SetScissor(0,0,rmode->fbWidth,rmode->efbHeight);
	GX_SetDispCopySrc(0,0,rmode->fbWidth,rmode->efbHeight);
	GX_SetDispCopyDst(rmode->fbWidth,xfbHeight);
	GX_SetCopyFilter(rmode->aa,rmode->sample_pattern,GX_TRUE,rmode->vfilter);
	GX_SetFieldMode(rmode->field_rendering,((rmode->viHeight==2*rmode->xfbHeight)?GX_ENABLE:GX_DISABLE));
 
	GX_SetCullMode(GX_CULL_NONE);
	GX_CopyDisp(frameBuffer[fb],GX_TRUE);
	GX_SetDispCopyGamma(GX_GM_1_0);
 

	// setup the vertex descriptor
	// tells the flipper to expect direct data
	GX_ClearVtxDesc();
	GX_SetVtxDesc(GX_VA_POS, GX_DIRECT);
 	GX_SetVtxDesc(GX_VA_CLR0, GX_DIRECT);
 
	// setup the vertex attribute table
	// describes the data
	// args: vat location 0-7, type of data, data format, size, scale
	// so for ex. in the first call we are sending position data with
	// 3 values X,Y,Z of size F32. scale sets the number of fractional
	// bits for non float data.
	GX_SetVtxAttrFmt(GX_VTXFMT0, GX_VA_POS, GX_POS_XYZ, GX_F32, 0);
	GX_SetVtxAttrFmt(GX_VTXFMT0, GX_VA_CLR0, GX_CLR_RGBA, GX_RGB8, 0);
 
	GX_SetNumChans(1);
	GX_SetNumTexGens(0);
	GX_SetTevOrder(GX_TEVSTAGE0, GX_TEXCOORDNULL, GX_TEXMAP_NULL, GX_COLOR0A0);
	GX_SetTevOp(GX_TEVSTAGE0, GX_PASSCLR);

	// setup our camera at the origin
	// looking down the -z axis with y up
	guVector cam = {0.0F, 0.0F, 0.0F},
			up = {0.0F, 1.0F, 0.0F},
		  look = {0.0F, 0.0F, -1.0F};
	guLookAt(view, &cam, &up, &look);
 

	// setup our projection matrix
	// this creates a perspective matrix with a view angle of 90,
	// and aspect ratio based on the display resolution
    f32 w = rmode->viWidth;
    f32 h = rmode->viHeight;
	guPerspective(perspective, 45, (f32)w/h, 0.1F, 300.0F);
	GX_LoadProjectionMtx(perspective, GX_PERSPECTIVE);
 
	while(1) {

		WPAD_ScanPads();

		if (WPAD_ButtonsDown(0) & WPAD_BUTTON_HOME) exit(0);
		if (WPAD_ButtonsDown(0) & WPAD_BUTTON_LEFT)
			if (scissor_mode > 0)
				scissor_mode -= 1;
		if (WPAD_ButtonsDown(0) & WPAD_BUTTON_RIGHT)
			if (scissor_mode < 5)
				scissor_mode += 1;


		// do this before drawing
		GX_SetViewport(0,0,rmode->fbWidth,rmode->efbHeight,0,1);

		switch (scissor_mode)
		{
		case 0:
			GX_SetScissor(0,0,rmode->fbWidth,rmode->efbHeight);
			break;
		case 1:
			// "normal" scissor
			GX_SetScissor(150, 150, rmode->fbWidth - 300, rmode->efbHeight - 300);
			break;
		case 2:
			// left/right inverted
			GX_SetScissor(rmode->fbWidth - 150, 150, -(rmode->fbWidth - 300), rmode->efbHeight - 300);
			break;
		case 3:
			// top/bottom inverted
			GX_SetScissor(150, rmode->efbHeight - 150, rmode->fbWidth - 300, -(rmode->efbHeight - 300));
			break;
		case 4:
			// zero width
			GX_SetScissor(150, 150, 0, rmode->efbHeight - 300);
			break;
		case 5:
			// zero height
			GX_SetScissor(150, 150, rmode->fbWidth - 300, 0);
			break;
		}

		guMtxIdentity(model);
		guMtxTransApply(model, model, -1.5f,0.0f,-6.0f);
		guMtxConcat(view,model,modelview);
		// load the modelview matrix into matrix memory
		GX_LoadPosMtxImm(modelview, GX_PNMTX0);

		GX_Begin(GX_TRIANGLES, GX_VTXFMT0, 3);
			GX_Position3f32( 0.0f, 1.0f, 0.0f);		// Top
			GX_Color3f32(1.0f,0.0f,0.0f);			// Set The Color To Red
			GX_Position3f32(-1.0f,-1.0f, 0.0f);	// Bottom Left
			GX_Color3f32(0.0f,1.0f,0.0f);			// Set The Color To Green
			GX_Position3f32( 1.0f,-1.0f, 0.0f);	// Bottom Right
			GX_Color3f32(0.0f,0.0f,1.0f);			// Set The Color To Blue
		GX_End();

		guMtxTransApply(model, model, 3.0f,0.0f,0.0f);
		guMtxConcat(view,model,modelview);
		// load the modelview matrix into matrix memory
		GX_LoadPosMtxImm(modelview, GX_PNMTX0);

		GX_Begin(GX_QUADS, GX_VTXFMT0, 4);			// Draw A Quad
			GX_Position3f32(-1.0f, 1.0f, 0.0f);	// Top Left
			GX_Color3f32(0.5f,0.5f,1.0f);			// Set The Color To Blue
			GX_Position3f32( 1.0f, 1.0f, 0.0f);		// Top Right
			GX_Color3f32(0.5f,0.5f,1.0f);			// Set The Color To Blue
			GX_Position3f32( 1.0f,-1.0f, 0.0f);	// Bottom Right
			GX_Color3f32(0.5f,0.5f,1.0f);			// Set The Color To Blue
			GX_Position3f32(-1.0f,-1.0f, 0.0f);	// Bottom Left
			GX_Color3f32(0.5f,0.5f,1.0f);			// Set The Color To Blue
		GX_End();									// Done Drawing The Quad 

		// do this stuff after drawing
		GX_DrawDone();
		
		fb ^= 1;		// flip framebuffer
		GX_SetZMode(GX_TRUE, GX_LEQUAL, GX_TRUE);
		GX_SetColorUpdate(GX_TRUE);
		GX_CopyDisp(frameBuffer[fb],GX_TRUE);

		VIDEO_SetNextFramebuffer(frameBuffer[fb]);
 
		VIDEO_Flush();
 
		VIDEO_WaitVSync();


	}
	return 0;
}